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Introduction: Pulmonary hypertension (PH) is a common and significant comorbidity in patients with low-flow low-gradient (LF-LG) aortic stenosis, impacting prognosis after transcatheter aortic valve replacement (TAVR). Non-invasive tools often fail to capture PH's full clinical impact due to inherent limitations. This study evaluates the prognostic significance of PH measured invasively and explores its implications on post-TAVR outcomes., Methods: This retrospective study analyzed 90 patients with symptomatic LF-LG aortic stenosis who underwent TAVR. Pulmonary artery systolic pressure (PASP) was categorized as mild (<35 mmHg), moderate (35-50 mmHg), or severe (>50 mmHg) using invasive right heart catheterization. Key endpoints included 12-month all-cause mortality and heart failure rehospitalization, assessed via Kaplan-Meier survival analysis and Cox proportional hazards modeling., Results: PH was present in 50% of patients, with moderate-to-severe cases showing higher mortality (25% vs. 8%, p < 0.001) and rehospitalization rates (20% vs. 6%, p = 0.02). Baseline PASP emerged as an independent predictor of mortality (HR 1.07 per mmHg, p < 0.001) and rehospitalization (HR 1.04 per mmHg, p = 0.01). Subgroup analyses revealed that patients with concomitant COPD or advanced diastolic dysfunction exhibited worse outcomes, underscoring the role of systemic disease burden., Conclusion: Invasive hemodynamic assessment provides superior prognostic insight for PH in LF-LG aortic stenosis patients. The findings advocate for targeted PH management strategies to improve post-TAVR outcomes and challenge the sole reliance on non-invasive methods in high-risk cohorts., Competing Interests: Declaration of competing interest The authors have nothing to declare. The authors have no conflicts of interest., (Copyright © 2024. Published by Elsevier B.V.)

Purpose: The impact of donor pulmonary hemodynamics as assessed by mean pulmonary artery pressure (mPAP) and transpulmonary gradients (TPG) on the clinical outcome of heart transplant (HT) recipients is unknown. We compared outcomes of adult HT recipients as stratified by donor pulmonary hemodynamics in the contemporary era in the United States., Methods: We reviewed adult donor hearts (age ≥ 18 years) which were offered for transplantation between January 2010 and March 2023 in the UNOS database with available right heart catheterization (RHC) data. Adjusted Cox regression was performed to evaluate the relationship between 30-day and 1-year mortality after HT and donor mPAP, TPG, and mean arterial pressure (MAP). Each hemodynamic parameter was modeled as a quadratic polynomial to not assume a linear relationship with mortality., Results: 2038 HT recipients with complete donor RHC were included: 58 % were on inotrope support. Elevated mPAP (≥25 mmHg), TPG (≥15), and PVR (≥1.5) were present in 416 (20.4 %), 179 (8.8 %), and 2038 (100 %), respectively. No significant association was found between donor mean PAP (HR 1.47, 95 % CI 0.80-2.67), donor TPG (HR 0.47, 95 % CI 0.20-1.08), and donor PVR (HR 1.69, 95 % CI 0.77-3.72) and 30-day mortality. Similarly, no significant association was found between donor mPAP (HR 1.33, 95 % CI 0.90-1.95), donor TPG (HR 0.65, 95 % CI 0.37-1.12), and donor PVR (HR 1.38, 95 % CI 0.83-2.32) and 1-year mortality., Conclusions: Donor pulmonary pressures did not impact post-heart transplant survival in adult recipients. Donors with abnormal pulmonary hemodynamics remain viable donor hearts for transplantation., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Reduced effective circulating blood volume and impaired peripheral tissue perfusion play an important role in the pathophysiology of shock. However, there have been no studies examining the relationship between Doppler ultrasound of the superior mesenteric artery (SMA) under different shock conditions., Methods: We evaluated a total of 85 patients, including 63 patients with different types of shock and 22 in the control group. we included patients who were diagnosed with shock upon admission or developed shock during their hospital stay. At the same time, patients with stable hemodynamics, no use of vasoactive drugs and normal lactate levels were used as a control group. We collected SMA Doppler ultrasound parameters, including Peak Systolic Velocity (PSV), End Diastolic Velocity (EDV), Resistance Index (RI), pulsatility index (PI), Time-Averaged Mean Velocity (TAMV), and Blood Flow (BF)., Results: In the cardiac shock group, SMA PSV, TAMV, and BF were lower compared to the other groups. There was no significant difference in SMA RI and PI between the different types of shock groups, but both were significantly lower than the control group. Cardiac index (CI) is correlated with SMA PSV (r = 0.487, P = 0.000) and TAMV (r = 0.538, P = 0.000), whereas SVRI is not correlated with SMA RI and PI. Lactate levels was correlation with SMA RI (r = -0.307, P = 0.000) and PI (r = -0.287, P = 0.000). The area under the ROC curve of SMA RI and PI to predict hyperlactatemia was 0.85[0.78-0.91] and 0.83[0.76-0.90]., Conclusions: The velocity parameters of SMA Doppler ultrasound such as TAMV and PSV can reflect cardiac function. The measurements of SMA RI and PI are correlated with lactate levels, having a positive predictive value for hyperlactatemia and provide guidance for fluid resuscitation in patients with shock in the future., Competing Interests: Declaration of competing interest The authors report no conflict of interests, (Copyright © 2024 Southern Society for Clinical Investigation. Published by Elsevier Inc. All rights reserved.)

Background: Infusion therapy is widely used in clinical settings, particularly in intensive care units., Aim: to explore the influence of simulated cardiac output on "bolus" or "backflow" events that can occur during syringe pump changeover, considering several factors that have been previously outlined in published research. Syringe infusion pumps are commonly used for precise continuous intravenous drug delivery. Syringe pump changeover can be a challenging procedure., Methods: Bench-top study in a laboratory setting. An extracorporeal circuit was used to simulate a cardiac output of 5 l/min. The following variables were used: three levels of vertical position of the syringe pump (-50 cm, 0, +50 cm), three levels of Central Venous Pressure (-5, 10, and 15 mmHg), presence/absence of carrier infusion (5 ml/h), and presence/absence of a needle-free connector between the syringe and extension line., Results: A total of 108 syringe pump changes were performed with different combinations of the investigated variables. The mean time for syringe pump changeover was equal to 9.48 ± 2.45 s and the overall fluid displacement was 8 ± 40 µL (microlitres) (range, -262-156 µL). The CVP level and vertical position of the pump always statistically affected the overall displacement during syringe pump changeover. When a second infusion with an equal velocity rate to that of a syringe pump infusion is present in the same lumen, the presence of a needle-free device reduces the overall volume of displacement., Conclusions: Syringe pump changeover can be a critical moment for patients when vasoactive drugs are administered., Implications for Clinical Practice: In a simulated environment with a cardiac output of 5 L/min, the CVP level and vertical position of the syringe pump generated bolus or backflow events during the syringe pump changeover. The application of carrier infusion appeared to intensify these phenomena. Employing a neutral, needle-free system can potentially aid in reducing the development of boluses or backflows., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background & Aims: The optimal timing of measurement and hemodynamic targets of portacaval pressure gradient (PPG) after transjugular intrahepatic portosystemic shunt (TIPS) placement remain unclear. This study aimed to identify the ideal moment for hemodynamic measurements and the optimal target of PPG in patients undergoing covered TIPS for variceal bleeding., Methods: Between May 2018 and December 2021, 466 consecutive patients with recurrent variceal bleeding treated with covered TIPS were prospectively included. Post-TIPS PPG was measured immediately (immediate PPG), 24-72 hours (early PPG), and again 1 month (late PPG) after TIPS placement. The agreement among PPGs measured at different time points was assessed by intra-class correlation coefficient (ICC) and Bland-Altman method. The unadjusted and confounder-adjusted effects of PPGs on clinical outcomes (portal hypertensive complications [PHCs], overt hepatic encephalopathy [OHE], further decompensation, and death) were assessed using Fine and Gray competing risk regression models., Results: The agreement between early PPG and late PPG (ICC: 0.34) was better than that between immediate PPG and late PPG (ICC: 0.23, p <0.001). Early PPG revealed an excellent predictive value for PHCs (early PPG≥ vs. <12 mmHg: adjusted hazard ratio 2.17, 95% CI 1.33-3.55, p = 0.002) and OHE (0.40, 95% CI 0.17-0.91, p = 0.030), while immediate PPG did not. Late PPG showed a predictive value for PHC risk but not OHE. By targeting the lowest risk of further decompensation, we identified an optimal hemodynamic target with early PPG ranging from 11 to 14 mmHg that was associated with a decreased risk of OHE and effective prevention of PHCs., Conclusions: PPG measured 24 to 72 hours after TIPS correlates with long-term PPG and clinical outcomes, and a hemodynamic target PPG of 11-14 mmHg is associated with reduced encephalopathy but not compromised clinical efficacy., Impact and Implications: The optimal timing of measurement and hemodynamic targets of portacaval pressure gradient (PPG) after transjugular intrahepatic portosystemic shunt (TIPS) remain unclear. Here we show that post-TIPS PPG measured at least 24 hours but not immediately after the procedure correlated with long-term PPG and clinical events. Thus, PPG measurements taken at least 24 hours after TIPS should be used to guide decision making in order to improve clinical outcomes. Targeting a post-TIPS PPG of 11-14 mmHg or a 20%-50% relative reduction from pre-TIPS baseline measured 24-72 hours after the procedure was associated with reduced encephalopathy but not compromised clinical efficacy. Thus, these criteria could be used to guide TIPS creation and revision in patients with cirrhosis and variceal bleeding undergoing covered TIPS., Clinical Trial Registration Number: ClinicalTrials.gov, ID: NCT03590288., (Copyright © 2024 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

Background and Objectives: The liver, a vital metabolic organ, is always susceptible to various diseases that ultimately lead to fibrosis, cirrhosis, acute liver failure, chronic liver failure, and even cancer. Optimal and specific medicine delivery in various diseases, hepatectomy, shunt placement, and other surgical interventions to reduce liver damage, transplantation, optimal preservation, and revival of the donated organ all rely on a complete understanding of perfusion and mass transfer in the liver. This study aims to simulate the computational fluid dynamics of perfusion and the temporal-spatial distribution of a medicine in a healthy liver to evaluate the hemodynamic characteristics of flow and medicine transport with the purpose of more effective liver treatment., Methods: Patient-specific geometries of parenchyma and hepatic artery, portal vein, and hepatic vein vessels of a healthy liver were segmented and reconstructed from the abdominal computed tomography scan images. Mesh was generated for the comprehensive combined model using unstructured tetrahedral elements. Transient pressure values were applied as boundary conditions at the portal vein and hepatic artery inlets, and pressure outlet boundary condition was assumed at the hepatic vein outlet. Medicine injection was done through the portal vein. The liver parenchyma was assumed to be a porous medium. Finally, computational fluid dynamics (CFD) simulation was performed to investigate blood perfusion, medicine distribution, and saturation time., Results: The velocity parameter values calculated for the hepatic artery, portal vein, and hepatic vein vessels were consistent with the physiological ranges. The mass flow rate was higher in the portal vein than in the hepatic artery, which was consistent with high perfusion through the portal vein. The portal pressure gradient was 8.53 mmHg. From a pharmacokinetic viewpoint, medicine distribution in porous tissue was a heterogeneous process. Medicine distribution was higher at end-diastolic pressure than at peak-systolic pressure which showed the influence of hepatic artery flow. The tissue was saturated faster at first 40 s and with decreasing porosity, saturation time decreased, and distribution improved., Conclusion: The right lobe included a higher number of vascular terminals due to its larger volume, and the flow rate was higher in this lobe compared to the left lobe. This showed the significant effect of the right lobe on the overall function of the body. Recirculation flow zones along hepatic artery and portal vein branches emphasized the sensitivity of downstream vessels. Rotational flow and potential vortex formation at the hepatic vein outlet may indicate a risk of plaque and clot formation in this region. The heterogeneous distribution of medicine indicated the importance of injection time in treating liver diseases. The percentage of tissue porosity affected the saturation time, so adjusting the medicine dose and injection time could be challenging in treatments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Research on venous hemodynamics is pivotal for unravelling venous diseases, including varicose veins and deep vein thrombosis, essential for clinical management, treatment and artificial valve design. In this study, a three-dimensional (3D) numerical simulation, employing the immersed boundary/finite element method, is constructed to explore the fluid-structure interaction (FSI) between intravenous blood and venous valves. A hyperelastic constitutive model is used to capture the incompressible, nonlinear mechanical response. Our findings reveal the periodic characteristics of valve movement and intravenous blood flow throughout the cardiac cycle, alongside quantified physiological parameters such as blood pressure, flow rate, geometric orifice area, and stress-strain distribution on venous valve surfaces. The study unveils a significant correlation between dynamic valve motion and vortices within the venous sinus. Stress and strain concentrate primarily at the free edge of venous valves, which is in contrast to 2D modelling. Moreover, increased hydrostatic venous pressure is found to be the key to venous vessel dilation. The effects of fibrosis and atrophy of venous valves on venous hemodynamics are compared and analysed. This FSI numerical study introduces a fully 3D framework for modelling the venous system, expected to provide crucial references for understanding the development and mechanism underlying venous diseases, thereby furnishing a scientific underpinning for their prevention, diagnosis, and treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Pulmonary hypertension (pH) and secondary right ventricle dysfunction is present in 20 % of adults with coarctation of aorta (COA) based on echocardiographic studies. There are limited data about invasive hemodynamic characterization of PH in COA. The purpose of this study was to delineate the clinical features, hemodynamics, and outcomes of PH in COA., Method: Retrospective cohort study of adults with repaired COA that underwent right heart catheterization (RHC). PH was defined as pulmonary artery (PA) mean pressure > 20 mmHg, and PH was classified as isolated precapillary PH and combined pre/postcapillary PH., Results: Of 99 COA patients that underwent RHC, 57 (58 %) had PH. Of the patients with PH, 14 (25 %) had isolated precapillary PH while 43 (75 %) had postcapillary PH with or without precapillary disease. The correlates of PH were PA compliance (adjusted OR 0.79, 95 % CI 0.71-0.86 per 1 ml/mmHg), left atrial reservoir strain (adjusted OR 0.95, 95 % CI 0921-0.98 per 1 %), and atrial fibrillation (adjusted OR 2.18, 95 % CI 1.20-13.5). Higher PA mean pressure was associated with risk of cardiovascular events (adjusted HR 1.04, 95 % CI 1.02-1.06 per 1 mmHg) and all-cause mortality (adjusted HR 1.05, 95 % CI 1.02-1.08 per 1 mmHg)., Conclusions: PH was present in over half of adults with COA referred for RHC, and one-quarter of the patients with PH presented with isolated precapillary PH suggesting an underlying PA vascular dysfunction as a contributing mechanism. Further studies are required to determine optimal therapies and strategies for prevention and treatment of PH in this population., Clinical Summary: Of 99 adults with repaired coarctation of aorta (COA) that underwent right heart catheterization, 57 % had pulmonary hypertension (pH). Of the patients with PH, 25 % had isolated precapillary PH while 75 % had combined pre/postcapillary PH. The correlates of PH were pulmonary artery (PA) compliance, left atrial reservoir strain and atrial fibrillation. PH was associated with cardiovascular events and all-cause mortality. These data suggest PA vascular dysfunction in addition to left-sided heart disease as potential etiologies for PH in this population. Further studies are required to determine optimal therapies and strategies for prevention and treatment of PH in this population., Competing Interests: Declaration of competing Interest None., (Copyright © 2024. Published by Elsevier B.V.)

The catheterization of women with congenital heart disease has unique considerations that must be taken into account. Hemodynamic changes secondary to pregnancy, anticoagulation strategies of women in child bearing years, and protection of a fetus during pregnancy require interventions and evidence of current therapies in the treatment of women continues to have more questions than answers in our current era. This review highlights some challenges in the catheterization of women with congenital heart disease., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Purpose: We described clinical outcomes for patients with blunt splenic injuries treated with transarterial embolization (TAE) based on their hemodynamic status., Materials and Methods: This is a retrospective two-center study of adult patients with splenic injuries who underwent emergency TAE between January 2011 and December 2022. Patients were divided into two groups; hemodynamically unstable (HDU) and hemodynamically stable (HDS) patients. HDU patients were defined as transient- or non-responders to fluid resuscitation and HDS as responders. When immediate laparotomy was not possible for HDU patients, angiography and embolization were performed. The primary outcome was the survival discharge rate. Rebleeding and splenectomy rate was also investigated., Results: Of 38 patients underwent emergency TAE for splenic trauma, 17 were HDU patients and 21 were HDS patients. The survival discharge rate was 88.2 % (15/17) in the HDU- and 100 % in HDS patients (p = 0.193). Rebleeding rate was 23.5 % (4/17) in HDU- and 5.0 % (1/21) in HDS patients (p = 0.15). Splenectomy was required for one HDU patient (5.9 %) for rebleeding., Conclusion: The survival discharge rate of TAE for splenic trauma in HDU patients was acceptable with a low rate of splenectomy. Further comparative studies of TAE versus operative management in HDU patients are needed to prove the usefulness of TAE., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Investigating magnetic blood flow characteristics through arteries and micron-size channels for clinical therapies in biomedicine is becoming increasingly important with the rise of point-of-care diagnostics devices. A computational fluid dynamics (CFD) investigation is conducted to explore blood flow within a coronary artery affected by an elliptical stenosis near the artery wall under the influence of a magnetic field. The novelty of our study is the integration of Navier-Stokes and Maxwell's equations to calculate body forces on fluid flow, coupled with the application of magnetic fields both longitudinally and vertically, and the use of the Carreau-Yasuda model to analyse non-Newtonian blood rheology. Blood flow is modelled by solving the incompressible continuity and momentum equations, considering laminar and non-Newtonian properties, with the finite element-based solver COMSOL Multiphysics. The CFD model is validated using previously published analytical and computational data. This study investigates the effects of magnetic fields on blood flow through stenotic arteries with 25 %, 35 %, and 50 % stenosis, examining how the magnetic field and its orientation impact variations in velocity profiles, pressure drop, and wall shear stress (WSS). Our results show that magnetic fields can effectively manipulate blood flow, causing acceleration or deceleration depending on field direction. Significant changes in hemodynamics are observed, particularly at 50 % arterial stenosis, highlighting the profound impact of stenosis on flow characteristics. Compared to healthy arteries, the velocity change in stenosed arteries increased by 16.5 %, 29.4 %, and 62.1 % for 25 %, 35 %, and 50 % stenosis, respectively. The findings advance experimental models of blood flow in magnetic fields, highlighting the critical importance of regulating blood velocity and pressure. These insights are particularly valuable for developing drug delivery systems and magnetic-driven blood pumps., Competing Interests: Declaration of competing interest The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Trauma during pregnancy presents multifaceted risks to both the developing fetus and the expectant mother due to pregnancy-induced physiological adaptations that affect the response to traumatic injuries. The infrequent occurrence of cardiac arrest during pregnancy necessitates interventions such as perimortem cesarean section (PMCS), now termed resuscitative hysterotomy. While early resuscitative hysterotomy focused primarily on fetal survival, more recent literature reports substantial maternal benefits. Resuscitative hysterotomy can lead to the restoration of maternal pulse and blood pressure within minutes and has shown potential to improve maternal outcomes. RH has been demonstrated to aid in fetal and maternal survival in hemodynamic unstable pregnant patients before cardiovascular collapse. The linguistic change from PMCS to resuscitative hysterotomy is a shift towards maternal-centric approaches and survival., Objective: In this series, we evaluate the outcomes of resuscitative hysterotomy performed before or after cardiovascular collapse to maximize maternal survival while concurrently optimizing fetal outcomes., Methods: We performed a retrospective case series review of 4 consecutive pregnant trauma patients who underwent RH due to hemodynamic instability. In addition, we conducted a descriptive analysis of all pregnant patients from 2013 to May 2024 who presented due to a traumatic injury but did not require a RH., Results: The average age of patients undergoing RH was 26.5 ± 6.8 years. All patients were in the third trimester with a mean gestational age of 32.3 ± 0.5 weeks. Fifty percent (50 %) of patients were involved in motor vehicle accidents, one (25 %) pedestrian was hit by a vehicle, and one (25 %) had GSW to the head. The median time to RH was 14.5 min. The mean estimated blood loss (EBL) was 625 mL ±108.9 mL. The maternal survival rate was 50 %, with a fetal survival rate of 100 %. Three patients achieved hemodynamic stability; however, one of the patients progressed to death by neurological criteria. Therefore, we achieved 50 % of maternal survival. A resuscitative hysterotomy was performed due to early signs of maternal hemorrhagic shock and suggestive features of ongoing bleeding (persistent maternal tachycardia despite adequate analgesia and resuscitation, persistent maternal bradycardia, gradual decline of BP, and FHR abnormalities) in three patients. The remaining patient was found to have cardiac arrest at the scene with a brief return of spontaneous circulation and received resuscitative hysterotomy in the ED to restore cardiovascular function., Conclusion: RH in pregnant patients with traumatic injury and impending hemorrhagic shock or cardiovascular collapse may provide maternal survival benefits by supporting circulatory function and promoting resuscitation with no additional risks to fetal outcomes. Quick decision-making is crucial to the implementation of this life-saving procedure. Further research with a more significant number of patients is needed to validate the efficacy of RH in maximizing maternal survival. This case series adds to the evolving literature on RH, shedding light on practical aspects and maternal outcomes to inform ongoing discussions and strategies for maternal cardiopulmonary resuscitation., Competing Interests: Declaration of competing interest None., (Copyright © 2024. Published by Elsevier Ltd.)

Objective: This study aims to investigate the micro-hemodynamic effects of strut malapposition in patient-specific stented coronary bifurcations., Methods: Using the mapping-back technique, three-dimensional reconstructions of clinical post-stenting artery bifurcations with strut malapposition were accurately generated from optical coherence tomography scans of 9 patients. Computational fluid dynamics (CFD) simulations were then conducted with these models to examine the impact of strut malapposition on various fluid dynamic parameters, including flow patterns, vorticity, strain rates, viscosity, and wall shear stress (WSS). For statistical analysis, virtually apposed models were created to evaluate WSS metrics. Additionally, follow-up data for 5 out of the 9 patients were reviewed to assess evidence of late thrombosis and restenosis., Results: Malapposed struts induce significant alterations in flow dynamics, including the formation of recirculation regions and the transition from laminar to disturbed flow. The local curvature of the lumen also affects the development of these recirculation regions. Our study demonstrates, for the first time, that the vorticity on the abluminal side of malapposed struts exhibits an opposite sign compared to the surrounding region. The strain rate around these struts shows a distinct transition, with high values at the stent surface that rapidly diminish within the strut-lumen gap. This transition is accompanied by an increase in viscosity within these regions. Furthermore, as the malapposition distance increases, strain rates on the malapposed struts increase while viscosity decreases. Significant differences in WSS metrics were observed between clinically malapposed and virtually apposed scenarios. In clinical follow-up cases, no evidence of thrombosis was found despite the complex micro-hemodynamics in these patients., Conclusion: There is complex interplay between stent malapposition and hemodynamics within a patient-specific bifurcation. The significant impact of local lumen curvature on flow dynamics underscores the limitations of idealized artery models. Moreover, the absence of thrombosis in subsequent clinical follow-up cases suggests that additional factors, such as antiplatelet medication, may play a significant role in mitigating these risks., Competing Interests: Declaration of competing interest Yiannis S. Chatzizisis: Speaker honoraria, advisory board fees, and research grant from Boston Scientific Inc.; Advisory board fees and research grant from Medtronic Inc.; Issued U.S. patent (No. 11,026,749) and international patent pending (application No. PCT/US2020/057304) for the invention entitled “Computational simulation platform for the planning of interventional procedures”; Co-founder of ComKardia Inc. All other authors have no relevant conflict of interests to disclose. This does not alter our adherence to Computers in Biology and Medicine's policies on sharing data and materials., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Reduced-order models allow for the simulation of blood flow in patient-specific vasculatures. They offer a significant reduction in computational cost and wait time compared to traditional computational fluid dynamics models. Unfortunately, due to the simplifications made in their formulations, reduced-order models can suffer from significantly reduced accuracy. One common simplifying assumption is that of continuity of static or total pressure over vascular bifurcations. In many cases, this assumption has been shown to introduce significant errors in pressure predictions. We propose a model to account for this pressure difference, with the ultimate goal of increasing the accuracy of cardiovascular reduced-order models. Our model successfully uses a structure common in existing reduced-order models in conjunction with machine-learning techniques to predict the pressure difference over a vascular bifurcation. We analyze the performance of our model on steady and transient flows, testing it on three bifurcation cohorts representing three different bifurcation geometric types. We find that our model makes significantly more accurate predictions than other models for approximating bifurcation pressure losses commonly used in the reduced-order cardiovascular modeling community. We also compare the efficacy of different machine-learning techniques and observe that a neural network performs most robustly. Additionally, we consider two different model modalities: one in which the model is fit using both steady and transient flows, and one in which it is optimized for performance in transient flows. We discuss the trade-off between the physical interpretability associated with the first option and the improved accuracy in transient flows associated with the latter option. We also demonstrate the model's ability to generalize by testing it on a combined dataset containing two different bifurcation types. This work marks a step towards improving the accuracy of cardiovascular reduced-order models, thereby increasing their utility for cardiovascular flow modeling., Competing Interests: Declaration of competing interest None Declared., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objectives: False lumen (FL) thrombosis status for Stanford type B aortic dissection (TBAD) after thoracic endovascular aortic repair (TEVAR) is critical for evaluating aortic remodeling and long-term prognosis. This study aimed to monitor the morphology evolution of partial FL thrombosis (PFLT) and its hemodynamic conditions through an innovative approach, providing a re-intervention strategy from both morphologic and hemodynamic perspectives., Methods: Three-dimensional geometries are extracted from a five-year follow-up of CTA images for TBAD after TEVAR. The morphology and hemodynamics of PFLT are comprehensively analyzed based on patient-specific reconstructions and computational fluid dynamics (CFD). The impact of various strategies treating risk factors of PFLT, including proximal entry closure, left renal artery stenting, or accessory renal artery embolism on hemodynamics is assessed., Results: The introduced morphologic approaches appropriately reflected the evolution of PFLT. Gradual dilation of FL (surface area from 82.63cm 2 to 98.84cm 2 , volume from 45.12 mL to 63.40 mL, increase in distal tear (from 3.72 cm to 4.32 cm), and fluctuation of thrombosis-blood lumen boundary are observed. For further surgical preparation in the absence of unanimously recognized re-intervention indicators, velocity and wall shear stress distributions reveal different simulated re-interventions have distinctly suppressive effects on hemodynamic conditions within the PFLT, providing valuable insights for further surgical preparation., Conclusions: The present study demonstrates a re-intervention strategy for PFLT in TBAD patients after TEVAR utilizing morphologic and hemodynamic analyses. Acknowledging the deterioration of PFLT may result in adverse long-term outcomes, this strategy might offer an alternative approach for clinical monitoring and management of related patients., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Pulmonary arterial hypertension (PAH) is a major concern in patients with Down syndrome (DS) and congenital heart disease (CHD). Understanding the unique characteristics of PAH in these populations is essential for developing tailored management strategies. This review examines differences in PAH between DS and non-DS (nDS) patients with CHD, focusing on pathophysiology, clinical presentation, hemodynamic profiles, and treatment outcomes., Methods: A retrospective analysis of 93 adults with PAH was conducted, including 18 with DS and 75 with CHD but without DS (nDS). Data on demographics, clinical presentations, comorbidities, and hemodynamic parameters were collected using echocardiography and right heart catheterization. Statistical analyses included Mann-Whitney U tests, Student's t-tests, and Kaplan-Meier survival analysis to compare the DS and nDS groups., Results: DS patients presented with PAH at a younger age (mean age 25.06 years) compared to nDS patients (mean age 42.4 years; p < 0.001). Hypothyroidism was more prevalent in DS patients (61.1 %) than in nDS patients (29.3 %; p = 0.012). Hemodynamic assessments showed lower mean arterial pressure (MAP) in DS patients (76.24 ± 11.6 mmHg) versus nDS patients (93.95 ± 15 mmHg; p < 0.001), and a higher TAPSE/PASP ratio (0.41 vs. 0.23; p = 0.009), suggesting less severe right ventricular dysfunction. DS patients had a significant survival advantage over nDS patients (p = 0.043)., Conclusions: DS patients have distinct clinical and hemodynamic profiles in PAH, requiring personalized management. Early detection and tailored treatment are crucial for improving outcomes. Further research should refine these strategies and explore new therapies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Introduction: The complex arborization of the feto-placental vasculature is crucial for optimal fetal nutrition, waste exchange and ultimately, development. Ethical and experimental limitations constrain research into the human placenta, hence experimental animal models such as mice and rats, are crucial to understand placental function. It is unclear how well the mouse and rat feto-placental vascular structure emulates human. Moreover, the implications of differences in vascular structure, especially in arborization, for placental function remain unclear., Methods: We use micro-computed tomography imaging, high frequency Doppler ultrasound and computational fluid dynamics to characterize feto-placental vasculature structure and haemodynamics in mice, rats, and human., Results: Our data suggest that despite structural differences between rat and mouse placenta, haemodynamics are similar and that both hold applicability to investigating feto-placental structure and function. We show that human cotyledons demonstrate vascularity-dependent haemodynamic behaviour (including flow deceleration and oxygen exchange) similar to rodents and can be analysed in the same spectrum as rodents. Finally, we show strong structure-function relationships when interspecies datasets are combined; notably, we demonstrate that surrogate measures such as vascularity, can be used to estimate placental oxygen exchange function., Discussion: Pre-clinical placental research utilising rat and mouse placentae to understand the impact of feto-placental arborization on placental function and fetal development can inform the human context., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Anaesthesiologists overwhelmingly favour pulse wave analysis techniques as their primary method to monitor cardiac output during high-risk noncardiac surgery. In patients with a radial arterial catheter in place, pulse wave analysis techniques have the advantage of instantly providing non-operator-dependent and continuous haemodynamic monitoring information. Green pulse wave analysis techniques working with any standard pressure transducer are as reliable as techniques requiring dedicated pressure transducers. They have the advantage of minimising plastic waste and related carbon dioxide emissions, and also significantly reducing hospital costs. The future integration of pulse wave analysis algorithms into multivariable bedside monitors, obviating the need for standalone haemodynamic monitors, could lead to wider use of haemodynamic monitoring solutions by further reducing their cost and carbon footprint., (Copyright © 2024 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.)

Background: The Fontan operation, a palliative procedure for single ventricle patients, has evolved to improve outcomes and reduce complications. While extracardiac conduit (ECC) is favored for its simplicity and potential hemodynamic benefits, concerns arise about conduit size adequacy over time. Undersized ECC conduits may cause hemodynamic inefficiencies and long-term complications, while oversizing can lead to flow disturbances, stagnation, and thrombosis, necessitating surgical revision or upsizing to optimize hemodynamics., Objectives: The study aimed to predict the impact of upsizing by developing a patient-specific workflow using cardiac magnetic resonance-based imaging and computational fluid dynamics to assess Fontan hemodynamic changes and determine the most optimal conduit size., Methods: We simulated upsizing in patient-specific models, computing reduction in power loss (PL), and analyzed pressure gradients, wall shear stress (WSS), and other local flow dynamic parameters such as vorticity and viscous dissipation that influence PL in a Fontan. Additionally, we quantified the impact of upsizing on hepatic flow distribution (HFD)., Results: Across the patient cohort, upsizing resulted in a PL reduction of 16 %-63 %, with the greatest reduction observed in patients with the smallest pre-existing conduit sizes (14 mm). The optimal conduit size for minimizing PL was highly patient-specific. For instance, a 20 mm conduit reduced PL by 63 % in one patient, while another patient showed 16 % reduction with upsizing. Pressure gradients decreased by 15 %-35 %, correlating with the reduction in PL, while WSS decreased consistently with upsizing. Vorticity and viscous dissipation exhibited more variability but followed the overall trend of reduced PL. HFD changes were modest with a maximum variation of 30 %., Conclusions: Our findings underscore the importance of individualized approaches in Fontan conduit upsizing. CFD-based quantitative evaluations of PL, pressure gradients, HFD, and WSS can guide optimal conduit sizing, improving long-term outcomes for patients., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:VG reports research funding from the AHA (19TPA34860013), the NHLBI/NIH (R01HL161507) and in-kind research support from NSF (high-performance computing resources from TACC). AS, EE, DH, PEH, and RR report research funding from the NHLBI/NIH (R01HL161507)., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Significant volume is pooled in veins in humans and the amount is dramatically altered by various physiological stresses and diseases. Several animal and human studies demonstrated that limb venous distension evoked significant increases in blood pressure and sympathetic nerve activity (venous distension reflex, VDR). VDR has attracted much attention because of its potential to explain the still unknown mechanism of autonomic dysfunction in several diseases, which would lead to a new treatment approach. This mini review discusses accumulated evidence of VDR at this point and what should be investigated in the future to apply the current understanding of VDR in clinical practice., Competing Interests: Declaration of competing interest The authors declare that there are no competing interests associated with the manuscript., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Pulmonary hypertension (PH) frequently complicates the evaluation of kidney transplantation (KT) candidates, and is associated with increased adverse outcomes (mortality, delayed graft function [DGF], and major adverse cardiovascular event) following KT., Research Question: What is the relationship between cardiopulmonary hemodynamics and post-KT outcomes?, Study Design and Methods: We conducted a multicenter retrospective cohort study of adults undergoing KT between October 1, 2011 and October 1, 2021, who underwent right heart catheterization (RHC) to assess cardiopulmonary hemodynamics within 1 year of transplantation. Frailty models and logistic regression models were used to evaluate the association between cardiopulmonary hemodynamics and outcomes (mortality, DGF, major adverse cardiovascular event) following KT., Results: A total of 117 patients were included in the final analysis, predominantly male (72%), with a median age of 57 years. PH, defined as mean pulmonary artery pressure (mPAP) > 20 mm Hg, was present in most of the cohort (n = 93; 79%). The cohort was monitored for a median of 29.9 months post-KT, during which about one-fourth experienced mortality (23%) or DGF (25%) events, and approximately one-third (34%) experienced major adverse cardiovascular event. Although echocardiographic measures of pulmonary artery pressure failed to identify post-KT outcomes, a mPAP of ≥ 30 mm Hg on RHC was associated with post-KT major adverse cardiovascular event (hazard ratio, 2.60; 95% CI, 1.10-6.10) and more prevalent in those experiencing post-KT mortality (63% vs 32%; P = .001). Precapillary pulmonary hypertension was also associated with post-KT mortality (hazard ratio, 3.71; 95% CI, 1.07-12.90)., Interpretation: Precapillary pulmonary hypertension and an mPAP of ≥ 30 mm Hg on RHC, but not echocardiographic evidence of PH, was associated with mortality and major adverse cardiovascular event following KT. These data suggest that RHC hemodynamics are superior to echocardiographic measures of PH in association with outcomes following KT, and RHC-derived mPAP in particular may have value in predicting major adverse cardiovascular event and mortality post-KT., Competing Interests: Financial/Nonfinancial Disclosures The authors have reported to CHEST the following: A. J. reports investigator-initiated research supported by United Therapeutics. S. S. K. has received research grant support from Edwards Life Sciences, Hemosonics, and PCORI. R. G. A. has received research grant support and served on the consultant or advisory board of United Therapeutics. N. M. B. is the site principal investigator for a clinical trial sponsored by Rednvia. J. M. E. has received research grant support from Janssen, United Therapeutics, Liquidia, Phase Bio, Gossamer Bio, Bayer, Merck, Altavant, Aerovate, Tenax, and Pharmosa, and serves on the consultant or advisory board of United Therapeutics, Altavant, Aerovate, Bayer, Gossamer Bio, Liquidia, Merck, and Janssen. None declared (L. G., S. H. F., A. S. F., D. S., M. V., N. J. D., A. P., C. J.)., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Hemodynamic factors play an important role in the formation and rupture of intracranial aneurysms. Blood viscosity has been recognized as a potential factor influencing the hemodynamics of aneurysms. Computational fluid dynamics (CFD) is one of the main methods to study aneurysm hemodynamics. However, current CFD studies often set the viscosity to a standard value, neglecting the effect of individualized viscosity on hemodynamics. We investigate the impact of blood viscosity on hemodynamics in large intracranial aneurysm (IA) and assess the potential implications for aneurysm growth and rupture risk., Methods: CFD simulations of 8 unruptured large internal carotid artery aneurysms were conducted using pulsatile inlet conditions. For each aneurysm, CFD simulations were performed at 5 different viscosity levels (0.004, 0.006, 0.008, 0.010, and 0.012 Pa·s). Differences in hemodynamic parameters across viscosity levels were compared using paired t-tests, and the correlation between viscosity and hemodynamic parameters was analyzed., Results: Increasing blood viscosity leads to significant decrease in blood flow velocity within aneurysms. Time-averaged wall shear stress (WSS) showed significant positive correlation with viscosity, particularly at the aneurysm neck. Oscillatory shear index (OSI) showed general decreasing trend with increased viscosity, while it displayed an irregular pattern in a few cases., Conclusions: Variations in viscosity markedly influence velocity, WSS, and OSI in aneurysms, suggesting a role in modulating aneurysm growth and rupture risk. Incorporating patient-specific viscosity values in CFD simulations is vital for accurate and reliable outcomes., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Invasive cardiopulmonary exercise testing (iCPET) combines traditional cardiopulmonary exercise testing with invasive hemodynamic measurements to assess exercise intolerance, which can be caused by preload insufficiency (PI), characterized by low ventricular filling pressures and reduced cardiac output during exertion. We hypothesize that plasma catecholamine levels at rest and during exercise correlate with hemodynamic parameters in PI., Methods: We included adult patients who underwent iCPET for exercise intolerance and had plasma catecholamines measured at rest and peak exercise., Results: Among 84 patients, PI was identified in 57 (67.8 %). Compared to patients without PI, those with PI were younger [median (IQR) 37 (28, 46) vs 47 (39,55) years, p = 0.005] and had lower workload at peak exercise [81 (66, 96) vs 95 (83.5, 110.50) Watts, p = 0.006]. Patients with PI had higher heart rates at rest and peak exercise [87 (78, 97) vs 79 (74, 87) bpm, p = 0.04; and 167 (154, 183) vs 156 (136, 168) bpm, p = 0.01, respectively]. In all patients, epinephrine and norepinephrine at peak exercise directly correlated with peak workload (r:0.41, p < 0.001 and r:0.47, p < 0.001, respectively). Resting epinephrine was higher in patients with PI [136 (60, 210) vs 77 (41, 110) pg/mL, p = 0.02]. There was no significant difference in the change in catecholamines from rest to peak exercise between patients with or without PI., Conclusion: PI patients exhibited elevated heart rate and epinephrine at rest, indicating increased sympathetic activity. We did not find strong associations between catecholamines and cardiac filling pressures, suggesting that catecholamine levels are predominantly influenced by peak workload., Competing Interests: Declaration of competing interest The authors have no significant conflicts of interest with any companies or organizations whose products or services may be discussed in this article., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Exercise hemodynamics are recommended for early detection of pulmonary arterial hypertension (PAH) and have been suggested to be predictive of future development of PAH in high-risk populations such as BMPR2 mutation carriers. However, the optimal exercise hemodynamic screening parameter remains to be determined. Recent data suggest that pulmonary vascular distensibility (α) may serve as a useful parameter for early detection of PAH., Research Question: What is the value of exercise hemodynamics, including α, for predicting the occurrence of PAH during long-term follow-up in BMPR2 mutation carriers?, Study Design and Methods: Fifty-two asymptomatic BMPR2 mutation carriers who underwent symptom-limited exercise hemodynamic assessment were followed up for a median of 10 years. The impact of hemodynamics at rest and exercise, presence of exercise pulmonary hypertension, and α on occurrence of PAH during long-term follow-up were assessed., Results: During long-term follow-up, five patients developed PAH. Patients who developed PAH showed a significantly lower α (0.8 ± 0.4%/mm Hg) than patients without PAH (1.8 ± 0.8%/mm Hg; P = .008). The only hemodynamic parameter that predicted the occurrence of PAH during long-term follow-up at regression analysis was α. Receiver operating characteristic analysis showed that α ≤ 1.5%/mm Hg predicted PAH occurrence with a specificity of 75% and sensitivity of 100%., Interpretation: The results of this study indicate that before development of PAH in BMPR2 mutation carriers, α is reduced markedly and may serve as a useful parameter in the setting of early disease detection. Given the low event rate, caution is warranted in interpreting these results, highlighting the need for validation studies., Competing Interests: Financial/Nonfinancial Disclosures The authors have reported to CHEST the following: C. G. has received compensation for scientific symposia from AstraZeneca, AOPHealth, Cordis, Janssen, and MSD; speaker fees from AOPHealth, AstraZeneca, Janssen, and Ferrer; and an educational grant from OrphaCare. A. Beurnier has received speaker fees from AstraZeneca and Sanofi Aventis. X. J. has received speaker fees from Janssen and MSD and research grants from Acceleron, Bayer, Janssen, and MSD. E. M. T. L. has received speaker fees from Janssen and GlaxoSmithKline and research grants from Janssen and has served as an advisory board member for Janssen. M. J. has received speaker fees from Janssen. A. Boucly has received compensation for scientific symposia from Janssen and MSD, speaker fees from Janssen, MSD, AOPHealth and Ferrer, and research grants from Acceleron, Janssen and MSD. H. J. B. has received speaker fees and research grants from Janssen, MSD, and Ferrer and consultancy fees from Novartis and was supported by the Dutch Cardiovascular Alliance [Grant 01-001-2017-B010, DOLPHIN-GENESIS]. G. S. has received speaker and consultancy fees from Janssen, Bayer, GlaxoSmithKline, MSD, and Pfizer and research grants from Janssen and has served as a steering committee member for Janssen. O. S. has received speaker fees from AOPHealth, Janssen, Ferrer, and MSD; consultancy fees from Acceleron, Altavant, AOPHealth, Ferrer, Gossamer Bio, Janssen, and MSD; and research grants from Acceleron, AOPHealth, Janssen, and MSD; and has served as an advisory board member for Altavant, Gossamer Bio, Janssen, and MSD. L. S. has received compensation for scientific symposia from Janssen and MSD and speaker fees from Janssen and has served as an advisory board member for Janssen. M. H. has received speaker fees from Janssen and MSD; consultancy fees from Acceleron, Aerovate, Altavant, AOPHealth, Bayer, Chiesi, Ferrer, Janssen, MSD, MorphogenIX, Shou Ti, Tiakis, and United Therapeutics; and research grants from Acceleron, AOPHealth, Janssen, MSD, and Shou Ti; and has served as an advisory board member for Acceleron, Altavant, Janssen, MSD, and United Therapeutics. D. M. has received speaker fees from Bayer, Janssen, and MSD; consultancy fees from Acceleron, Janssen, and MSD; and research grants from Acceleron, Janssen, and MSD. None declared (P. H., B. G., S. G., A. Bouchachi, D. C.)., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objective: This study undertook neuropharmacological research on the clinical course of controlled medication discontinuation to guide practitioners who are considering stopping medications for youths with attention-deficit hyperactivity disorder (ADHD)., Methods: This study analyzed the data for 14 ADHD children (12 male and 2 female) in two datasets: The children prescribed methylphenidate (MPH) were at an initial mean age of 7.5 years (SD = 1.70, range: 6-11) with a mean ADHD-Rating Score (ADHD-RS) of 26.6 (SD = 8.64, range 15-40). The children who discontinued MPH based on clinical judgment were at a mean age of 12.21 years (SD = 2.12, range: 8-15) with a mean ADHD-RS of 15.9 (SD = 6.86, range 5-27). The go/no-go task was used to assess response inhibition, while functional near-infrared spectroscopy (fNIRS) was used to measure cerebral hemodynamics. Oxygenated hemoglobin (Oxy-Hb) values from fNIRS data were analyzed for each subject, focusing on past and current measurements. Baseline was set at 10 s pre-task, with interval means from 4 to 24 s analyzed. One-sample t-tests were used to evaluate brain activity magnitude., Results: The results of the study demonstrate that the children who had discontinued the medication exhibited activation in specific brain regions including the frontopolar cortex and the right ventrolateral prefrontal cortex. Activation (t = 2.363, p = 0.034, Cohen's d = 0.632) was found especially in the right dorsolateral prefrontal cortex during the performance of the go/no-go task. These activated areas were consistent with those observed in a previous study comparing brain activity during a go/no-go task between children with ADHD and healthy children., Conclusion: The present study showed differences in cerebral hemodynamics before and after discontinuation of MPH in ADHD children whose ADHD symptoms did not recur after MPH was discontinued. In the near future, further investigations that include control groups will be conducted to demonstrate the effects of MPH prior to discontinuation based on the changes in cerebral blood flow in the right prefrontal cortex, which is involved in behavioral inhibition, as observed in this study. This and future research will facilitate the development of criteria for discontinuing treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have influenced or appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Objectives: The objective of this study was to assess the clinical, hemodynamic characteristics and immediate outcomes of Percutaneous Balloon Mitral Valvotomy (PBMV) in low gradient severe rheumatic mitral stenosis (LGMS) with normal cardiac index., Background: The optimal management of LGMS remains incompletely understood., Methods: We examined 200 consecutive patients with severe rheumatic mitral stenosis (MS) who underwent PBMV between January 2014 and March 2020., Results: Of the 149 patients (who satisfied inclusion criteria), 51 (34.2 %) had LGMS. The mean diastolic pressure gradient (DPG) was 8.70 ± 1.34 mm of Hg in LGMS as compared to 16.2 ± 4.3 mm of Hg in HGMS (p < 0.001). Patients of LGMS were older (39.5 ± 9.7 vs.34.9 ± 11.0 years, p = 0.012), had lower baseline heart rate (76.8 ± 9.5 vs 81.9 ± 12.5, p = 0.010), higher Mitral valve area (MVA) (1.16 ± 0.19 vs 0.99 ± 0.21 cm 2 ,p < 0.001),higher Wilkins score (5.8 ± 1.7 vs 4.9 ± 1.5, p = 0.002) and elevated left ventricular end diastolic pressure (LVEDP) (9.2 ± 2.8 vs 5.8 ± 1.2 mm of Hg,p=<0.001) but lower Pulmonary artery systolic pressure (PASP) (53.1 ± 14.5 vs 62.6 ± 17.8 mm of Hg, p = 0.001) and left atrial (LA) pressure (18.0 ± 3.1vs 22.0 ± 4.4 mm of Hg,p=<0.001). Although, the procedural success rate of PBMV was comparable between LGMS and HGMS (92.2 % vs 96.9 % p = 0.231) but increment in MVA and fall in DPG were significantly higher in HGMS in comparison to LGMS (p-value<0.05)., Conclusions: Significant MS may have "low" gradients during catheterization and yet be symptomatic, and thus low gradients cannot be alone used as a marker of disease severity. LGMS with normal CI is characterized by unique clinical and hemodynamic features. The immediate outcome of PBMV is comparable to HGMS but the hemodynamic parameters to monitor the success of PBMV are significantly different., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Cardiological Society of India. Published by Elsevier, a division of RELX India, Pvt. Ltd. All rights reserved.)

Accurate prenatal diagnosis of coarctation of the aorta (CoA) is challenging due to high false positive rate burden and poorly understood aetiology. Despite associations with abnormal blood flow dynamics, fetal arch anatomy changes and alterations in tissue properties, its underlying mechanisms remain a longstanding subject of debate hindering diagnosis in utero. This study leverages computational fluid dynamics (CFD) simulations and statistical shape modelling to investigate the interplay between fetal arch anatomy and blood flow alterations in CoA. Using cardiac magnetic resonance imaging data from 188 fetuses, including normal controls and suspected CoA cases, a statistical shape model of the fetal arch anatomy was built. From this analysis, digital twin models of false and true positive CoA cases were generated. These models were then used to perform CFD simulations of the three-dimensional fetal arch haemodynamics, considering physiological variations in arch shape and blood flow conditions across the disease spectrum. This analysis revealed that independent changes in the shape of. the arch and the balance of left-to-right ventricular output led to qualitatively similar haemodynamic alterations. Transitioning from a false to a true positive phenotype increased retrograde flow through the aortic isthmus. This resulted in the appearance of an area of low wall shear stress surrounded by high wall shear stress values at the flow split apex on the aortic posterior wall opposite the ductal insertion point. Our results suggest a distinctive haemodynamic signature in CoA characterised by the appearance of retrograde flow through the aortic isthmus and altered wall shear stress at its posterior side. The consistent link between alterations in shape and blood flow in CoA suggests the need for comprehensive anatomical and functional diagnostic approaches in CoA. This study presents an application of the digital twin approach to support the understanding of CoA mechanisms in utero and its potential for improved diagnosis before birth., Competing Interests: Declaration of competing interest None declared., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: The efficacy of balloon pulmonary angioplasty (BPA) in patients with chronic thromboembolic disease (CTEPD) without pulmonary hypertension (PH) remains unknown. Exercise PH (Ex-PH) is associated with impaired exercise capacity, even when pulmonary hemodynamics are normal at rest. We hypothesized that patients with Ex-PH could be the candidates for BPA. This study aimed to determine the prevalence and clinical profiles of Ex-PH and the effect of BPA on oxygenation and Ex-PH in patients with CTEPD and mean pulmonary arterial pressure (mPAP) ≤ 20 mmHg., Methods: We retrospectively reviewed 23 patients (median age 65 years) with CTEPD and mPAP ≤20 mmHg at rest who underwent cardiopulmonary exercise testing with right heart catheterization. Patients were divided into two groups: Ex-PH, defined by an mPAP/cardiac output (CO) slope (mPAP/CO slope) > 3.0, and non-Ex-PH., Results: Overall, 12 and 11 patients were identified as Ex-PH and non-Ex-PH groups, respectively. There were no significant differences in clinical parameters, including hemodynamics at rest, and blood gas analysis between Ex-PH and non-Ex-PH groups. Among 9 patients with Ex-PH, BPA improved World Health Organization-functional class and PaO 2 at rest and was associated with a decrease in the mPAP/CO slope. All 3 patients discontinued LTOT after BPA. There were no significant complications during each BPA session., Conclusions: Ex-PH was common among patients with CTEPD without PH. BPA could improve symptoms, oxygenation, and exercising hemodynamics in patients with CTEPD and Ex-PH., Competing Interests: Declaration of competing interest We have nothing to declare., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: This study seeks to quantify the effects of upper body veno-arterial extracorporeal membrane oxygenation (VA ECMO) on the anatomical distribution of oxygen delivery in the setting of hypoxic respiratory failure and provide new insights that will guide clinical use of this support strategy to bridge patients to lung transplant., Methods: Employing a patient-specific vascular geometry and a quantitative model of oxygen transport, computational simulations were performed to determine hemodynamics and oxygen delivery in the ascending and descending aorta, left and right coronary arteries, and great vessels during upper body VA ECMO support. Oxygen content in ECMO circuit blood flow was varied while considering different degrees of lung failure severity. Using lumped parameter models to dynamically apply perfusion boundary conditions, hemodynamic parameters and oxygen content were analyzed to assess the effect of ECMO supply titration., Results: The results emphasize the importance of anatomical distribution for tissue oxygen delivery in severe lung failure, with ECMO-derived flow primarily augmenting oxygen content in specific vascular beds. They also demonstrate that although cannulating the subclavian artery can enhance cerebral oxygen delivery, its ability to ensure sufficient oxygen delivery to the coronary circulation seems to be comparatively restricted., Conclusions: The oxygen delivery to a specific vascular area is primarily determined by the oxygen content in the source of perfusion. Caution is advised with upper body VA ECMO for patients with hypoxic respiratory failure and right ventricle dysfunction, due to potential coronary ischemia. Management of these patients is challenging due to disease progression and organ availability uncertainties., Competing Interests: Declaration of competing interest Hamed Moradi denies any competing interests. Raghu Seethala denies any competing interests. Elazer Edelman is the primary investigator of an educational grant to the Massachusetts Institute of Technology (MIT) from Abiomed, Inc. that investigates use of mechanical circulatory support devices. He has developed intellectual property that is licensed to Abiomed, Inc. through MIT. This work is in the related field of mechanical support but is not directly related to the submitted work. Farhad Nezami denies any competing interests. Steven Keller is a co-inventor of intellectual property with Dr. Edelman that is licensed to Abiomed, Inc. through MIT. This work is not directly related to the submitted work., (Copyright © 2024. Published by Elsevier Ltd.)

The spleen constantly clears altered red blood cells (RBCs) from the circulation, tuning the balance between RBC formation (erythropoiesis) and removal. The retention and elimination of RBCs occur predominantly in the open circulation of the spleen, where RBCs must cross submicron-wide inter-endothelial slits (IES). Several experimental and computational studies have illustrated the role of IES in filtrating the biomechanically and morphologically altered RBCs based on a rigid wall assumption. However, these studies also reported that when the size of IES is close to the lower end of clinically observed sizes (less than 0.5 μm), an unphysiologically large pressure difference across the IES is required to drive the passage of normal RBCs, sparking debates on the feasibility of the rigid wall assumption. In this work, We propose two deformable IES models, namely the passive model and the active model, aiming to explore the impact of the deformability of IES on the filtration function of the spleen. In the passive model, we implement the worm-like string model to depict the IES's deformation as it interacts with blood plasma and allows RBC to traverse. In contrast, the active model involved regulating the IES deformation based on the local pressure surrounding the slit. To demonstrate the validity of the deformable model, we simulate the filtration of RBCs with varied size and stiffness by IES under three scenarios: (1) a single RBC traversing a single slit; (2) a suspension of RBCs traversing an array of slits, mimicking in vitro spleen-on-a-chip experiments; (3) RBC suspension passing through the 3D spleen filtration unit known as'the splenon'. Our simulation results of RBC passing through a single slit show that the deformable IES model offers more accurate predictions of the critical cell surface area to volume ratio that dictate the removal of aged RBCs from circulation compared to prior rigid-wall models. Our biophysical models of the spleen-on-a-chip indicate a hierarchy of filtration function stringency: rigid model > passive model > active model, providing a possible explanation of the filtration function of IES. We also illustrate that the biophysical model of 'the splenon' enables us to replicate the ex vivo experiments involving spleen filtration of malaria-infected RBCs. Taken together, our simulation findings indicate that the deformable IES model could serve as a mesoscopic representation of spleen filtration function closer to physiological reality, addressing questions beyond the scope of current experimental and computational models and enhancing our understanding of the fundamental flow dynamics and mechanical clearance processes within in the human spleen., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Ltd.)

The etiology of spaceflight-associated neuro-ocular syndrome (SANS) remains unclear. Recent murine studies indicate there may be a link between the space environment and retinal endothelial dysfunction. Post-fixed control (N = 4) and 14-day tail-suspended (TS) (N = 4) mice eye samples were stained and imaged for the vessel plexus and co-located regions of endothelial cell death. A custom workflow combined whole-mounted and tear reconstructed three-dimensional (3D) spherical retinal plexus models with computational fluid dynamics (CFD) simulation that accounted for the Fåhræus-Lindqvist effect and boundary conditions that accommodated TS fluid pressure measurements and deeper capillary layer blood flow distribution. TS samples exhibited reduced surface area (4.6 ± 0.5 mm 2 vs. 3.5 ± 0.3 mm 2 , P = 0.010) and shorter lengths between branches in small vessels (<10 μm, 69.5 ± 0.6 μm vs. 60.4 ± 1.1 μm, P < 0.001). Wall shear stress (WSS) and pressure were higher in TS mice compared to controls, particularly in smaller vessels (<10 μm, WSS: 6.57 ± 1.08 Pa vs. 4.72 ± 0.67 Pa, P = 0.034, Pressure: 72.04 ± 3.14 mmHg vs. 50.64 ± 6.74 mmHg, P = 0.004). Rates of retinal endothelial cell death were variable in TS mice compared to controls. WSS and pressure were generally higher in cell death regions, both within and between cohorts, but significance was variable and limited to small to medium-sized vessels (<20 μm). These findings suggest a link may exist between emulated microgravity and retinal endothelial dysfunction that may have implications for SANS development. Future work with increased sample sizes of larger species or spaceflight cohorts should be considered., Competing Interests: Declaration of competing interest The authors have no competing interests to declare., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Liver fibrosis has been recognized as a long-term morbidity associated with Fontan circulation (Fontan-associated liver disease, FALD). The pathophysiology of FALD is not completely understood and abnormal flow dynamics may be associated with this condition. Liver hemodynamics can be quantitatively evaluated with four-dimensional phase-contrast flow magnetic resonance imaging (4D PC flow MRI). The study aimed to evaluate suitability of liver 4D PC flow MRI in Fontan patients and relate flow measurements to normal values and FALD severity., Patients and Methods: Twenty-two Fontan patients were examined by 4D PC flow MRI at 1.5 Tesla to assess mesenteric, portal, splenic, and hepatic venous blood flow. Severity of FALD was graded based on routine screening, including abdominal ultrasound and laboratory tests., Results: Median age was 18.5 (interquartile range, IQR 15.5-20.2) years. FALD was graded as "none or mild" in 16 and as "moderate to severe" in six cases. Ten patients presented at least one feature of portal hypertension (ascites, splenomegaly, or thrombocytopenia). For the entire cohort, blood flow in the superior mesenteric, splenic, and portal vein was lower than reported in the literature. No significant differences were observed in relation to FALD severity. Features of portal hypertension were associated with a higher splenic vein blood flow (0.34 ± 0.17 vs. 0.20 ± 0.07 l/min, p = 0.046). Splenic vein blood flow was negatively correlated to platelet count (r = -0.590, p = 0.005)., Conclusions: 4D PC flow MRI appears suitable to assess liver hemodynamics in Fontan patients and integration into clinical follow-up might help to improve our understanding of FALD., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Giant intracerebral aneurysms (GIA) comprise up to 5 % of all intracranial aneurysms. The indirect surgical strategy, which leaves the GIA untouched but reverses the blood flow by performing a bypass in combination with proximal parent artery occlusion is a useful method to achieve spontaneous aneurysm occlusion. The goal of this study was to assess the utility of computational fluid dynamics (CFD) in preoperative GIA treatment planning. We hypothesise that CFD simulations will predict treatment results. A fluid-structure interaction (FSI) CFD investigation was performed for the entire arterial brain circulation. The analyses were performed in three patient-specific CT angiogram models. The first served as the reference geometry with a C6 internal carotid artery (ICA) GIA, the second a proximal parent artery occlusion (PAO) and virtual bypass to the frontal M2 branch of the middle cerebral artery (MCA), and the third a proximal PAO in combination with a temporal M2 branch bypass. The volume of "old blood", flow residence time (FRT), dynamic viscosity and haemodynamic changes were also analysed. The "old blood" within the aneurysm in the bypass models reached 41 % after 20 cardiac cycles while in the reference model it was fully washed out. In Bypass 2 "old blood" was also observed in the main trunk of the MCA after 20 cardiac cycles. Extrapolation of the results yielded a duration of 4 years required to replace the "old blood" inside the aneurysm after bypass revascularization. In both bypass models a 7-fold increase in mean blood viscosity in the aneurysm region was noted. Bypass revascularization combined with proximal PAO favours thrombosis. Areas prone to thrombus formation, and subsequently the treatment outcomes, were accurately identified in the preoperative model. Virtual surgical operations can give a remarkable insight into haemodynamics that could support operative decision-making., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Accurate imaging reports of the aortic valve indicate that the diameter of the aortic annulus changes regularly during a cardiac cycle. Most of these studies aim to demonstrate the proper method for estimating the aortic annulus diameter before performing TAVR surgery, revealing that the aortic annulus is dynamic and not constant throughout the cardiac cycle. This raises the question of how fixing the aortic annulus might affect valve function, which is a question that still needs to be addressed. Therefore, the present study seeks to address this question and elucidate the dynamic impact of the aortic annulus on aortic valve hemodynamics. Two computational models based on this hypothesis were created and solved, and then their results were compared. Both models are identical, except for the intrinsic dynamic nature of the aortic annulus. One model consists of the dynamic behavior, and the other simulates a fixed annulus, resembling the effect of a TAVR operation, SAVR, or any phenomenon that eliminates the dynamic nature of the annulus. Our research findings indicate that the dynamic nature of the annulus enhances blood flow (+2.7 %), increases mean velocity (+11.9) and kinetic energy density (+34 %), prolongs momentum retention during systole, stabilizes the flow jet at the end of systole, reduces the required pressure to keep the leaflets open (-40.9 % at 0.3s), and sustains ventricular pressure superiority (+9.4 %) over the aorta for a longer duration (+17.7 % of systole), a crucial factor in preventing backflow during aortic valve closure. Based on these results, more attention should be paid to the dynamic nature of the annulus., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests related to this article. The authors have not received any funding or support from any organization or institution that could influence the analysis, or interpretation of the study. The authors have no personal, professional, or academic affiliations that could bias their work or compromise their integrity. The authors have no other relevant interests to declare., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Despite the known interplay between blood flow and function, to our knowledge, there is currently no minimally invasive method to monitor diaphragm hemodynamics. We used contrast-enhanced ultrasound to quantify relative diaphragm blood flow (Q˙ DIA ) in humans and assessed the technique's efficacy and reliability during graded inspiratory pressure threshold loading. We hypothesized that: (1) Q˙ DIA would linearly increase with pressure generation, and (2) that there would be good test-retest reliability and interanalyzer reproducibility., Research Question: Can we validate what is, to our knowledge, the first minimally invasive method to measure relative diaphragm blood flow in humans?, Study Design and Methods: Quantitative contrast-enhanced ultrasound of the costal diaphragm was performed in healthy participants (10 male participants, 6 female participants; mean age 28 ± 5 years; BMI 22.8 ± 2.0 kg/m) during unloaded breathing and three stages of loaded breathing on two separate days. Gastric and esophageal balloon catheters measured transdiaphragmatic pressure. Ultrasonography was performed during a constant-rate IV infusion of lipid-stabilized microbubbles following each stage. Ultrasound images were acquired after a destruction-replenishment sequence and diaphragm specific time-intensity data were used to determine Q˙ DIA by two individuals., Results: Transdiaphragmatic pressure for unloaded and each loading stage were 15.2 ± 0.8, 26.1 ± 0.8, 34.6 ± 0.8, and 40.0 ± 0.8 percentage of the maximum, respectively. Q˙ DIA increased with each stage of loading (3.1 ± 3.1, 6.9 ± 3.6, 11.0 ± 4.9, and 13.5 ± 5.4 acoustic units/s; P < .0001). The linear relationship between diaphragmatic flow and pressure was reproducible from day to day. Q˙ DIA had good to excellent test-retest reliability (0.86 [0.77, 0.92]; P < .0001) and excellent interanalyzer reproducibility (0.93 [0.90, 0.95]; P < .0001) with minimal bias., Interpretation: Relative Q˙ DIA measurements had valid physiological underpinnings, were reliable day-to-day, and were reproducible analyzer-to-analyzer. This study indicated that contrast-enhanced ultrasound is a viable, minimally invasive method for assessing costal Q˙ DIA in humans and may provide a tool to monitor diaphragm hemodynamics in clinical settings., Competing Interests: Financial/Nonfinancial Disclosures None declared., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Introduction: Subaxial cervical spine injuries (SCSI) can lead to disastrous consequences such as quadriplegia, with/without respiratory paralysis (RP) and hemodynamic instability (HDI). Till date, there is no literature available for reporting outcomes of SCSI patients specifically pertaining to those presenting with RP/HDI and ours is the first study to document the same., Methods: Retrospective 6-year study from a tertiary trauma centre database including patients >/= 18 years of operated SCSI. Only patients with ASIA A grade with admission RP/HDI and unstable injuries (fractures, subluxations) were included. Patients with ASIA grade B and above, patients with non-osseous injuries (such as disc herniation, central cord syndrome etc.) were excluded., Results: 24 cases were analysed. C5 and C6 levels were the commonest. Vertebral listhesis/subluxation was the predominant radiological finding. The mean age was 47.4 years (22-79 years) and all, except one were males. Fall from height and road traffic accident (RTA) were the most common mechanisms of injury. The most common surgery was anterior discectomy and fusion followed by corpectomy. The overall mortality rate was 22/24 (92)%. Cord edema and hemorrhage had significant association with survival. None of the grade A survivors with HDI/RP showed improvement. The mean FU duration was 18.5 months (range, 16.5-20.5 months)., Conclusions: Subaxial ASIA A cervical spine injuries with pre-operative RP/HDI is an indicator for non-improvement. This is the first study documenting outcome in such patients. The mortality rate in these patients is very high and is an extremely poor prognostic factor for recovery. Hence, surgery in such patients need to be decided judiciously, especially in developing countries that has a significant financial impact on the family members., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Introduction: Identification of severe blood loss and hemorrhagic shock in polytrauma patients poses a key challenge for trauma teams across the world, as there are just a few objective parameters, on which clinicians can rely. We investigated the relationship between exhaled air methane (CH 4 ) concentration and blood loss in a polytrauma patient. Decreased blood flow in the superior mesenteric artery (SMA) is one of the first compensatory responses to blood loss. Gases produced by the anaerobic flora of the intestinal segment supplied by the SMA are the primary source of exhaled CH 4 , which diffuses through the intestinal microvessels into the circulation and is finally eliminated through the lungs. We hypothesized that diminution of exhaled CH 4 indicates blood loss and tested our theory in a severely injured patient., Methods: Exhaled CH 4 concentrations of a severely injured patient were measured using a photoacoustic spectroscope (PAS) attached to the exhalation side of the breathing circuit. The primary objective was to investigate the relationship between exhaled CH 4 and conventional indicators of hemorrhage including hemoglobin (Hb) levels, base deficit (BD) values and vital parameters (heart rate and systolic blood pressure) in the early phase of in-hospital care (first 4 h)., Results: A severely injured patient was admitted with unstable hemodynamic parameters and incomplete left lower limb amputation, (Injury Severity Score: 38, 74/36 mmHg, 76 bpm). At the time of arrival, considerably lower CH 4 levels were detected (22,800 PAU) in the exhaled air. During the first 4 h fluid and massive blood resuscitation, the exhaled CH 4 levels were continuously rising in parallel with Htc and Hb values. Corresponding to these changes, BD values displayed a decreasing tendency., Discussion: Our study was conducted to characterize the changes in exhaled air CH 4 concentration in response to hemorrhagic shock and to provide data on a viable clinical use of an experimental technique. According to our results, the real-time detection of exhaled air CH 4 concentration is an applicable and promising technique for the early detection of bleeding and hemorrhagic shock in severely injured patients. Further research on large sample size and refinement of the PAS technique is required., Competing Interests: Declaration of competing interest None., (Copyright © 2024. Published by Elsevier Ltd.)

Background: There are limited data comparing hemodynamic valve function in mechanical aortic valve prostheses. This study compared the hemodynamic function of 2 commonly used mechanical aortic valve (AV) prostheses, the On-X (Artivion) and Top Hat (CarboMedics Inc) valves., Methods: This study was a retrospective analysis of 512 patients who underwent AV replacement with the On-X (n = 252; 49%) or Top Hat (n = 260; 51%) mechanical valves between 2011 and 2019. Patients were matched on the basis of selected variables. Echocardiographic data were collected preoperatively and postoperatively over a median follow-up of 1.39 years., Results: A total of 320 patients were matched, 160 patients in each group. Despite being matched for left ventricular outflow tract diameter, patients in the Top Hat group received a greater prevalence of smaller tissue annulus diameter valves (≤21 mm) (83% vs 38%; P < .001). Patients in the On-X group had longer aortic cross-clamp times (78 minutes vs 64 minutes; P < .001) during isolated aortic valve replacement. Discharge echocardiography showed no difference in the AV area index between both groups (1.00 cm 2 /m 2 vs 1.02 cm 2 /m 2 ; P = .377). During longer-term echocardiographic follow-up, the AV area index remained stable for both valves within their respective tissue annulus diameter groups (P = .060)., Conclusions: There was no difference between the 2 valves with respect to the AV area index at discharge, and hemodynamic function was stable during longer-term follow-up. The longer aortic cross-clamp time observed in the On-X group may indicate increased complexity of implantation compared with the Top Hat group., Competing Interests: Disclosures The authors have no conflicts of interest to disclose., (Copyright © 2024 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Left ventricular (LV) unloading by Impella, an intravascular microaxial pump, has been shown to exert dramatic cardioprotective effects in acute clinical settings of cardiovascular diseases. Total Impella support (no native LV ejection) is far more efficient in reducing LV energetic demand than partial Impella support, but the manual control of pump speed to maintain stable LV unloading is difficult and impractical. We aimed to develop an Automatic IMpella Optimal Unloading System (AIMOUS), which controls Impella pump speed to maintain LV unloading degree using closed-feedback control. We validated the AIMOUS performance in an animal model., Methods: In dogs, we identified the transfer function from pump speed to LV systolic pressure (LVSP) under total support conditions (n = 5). Using the transfer function, we designed the feedback controller of AIMOUS to keep LVSP at 40 mmHg and examined its performance by volume perturbations (n = 9). Lastly, AIMOUS was applied in the acute phase of ischemia-reperfusion in dogs. Four weeks after ischemia-reperfusion, we assessed LV function and infarct size (n = 10)., Results: AIMOUS maintained constant LVSP, thereby ensuring a stable LV unloading condition regardless of volume withdrawal or infusion (±8 ml/kg from baseline). AIMOUS in the acute phase of ischemia-reperfusion markedly improved LV function and reduced infarct size (No Impella support: 13.9 ± 1.3 vs. AIMOUS: 5.7 ± 1.9%, P < 0.05)., Conclusions: AIMOUS is capable of maintaining optimal LV unloading during periods of unstable hemodynamics. Automated control of Impella pump speed in the acute phase of ischemia-reperfusion significantly reduced infarct size and prevented subsequent worsening of LV function., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Introduction: Coexistence of chronic obstructive pulmonary disease(COPD) and heart failure(HF) is associated with systemic inflammation, myocardial injury, and arterial stiffening, impacting cardiovascular risk and prognosis in patients. Arterial stiffness, reduced nitric oxide synthesis, and altered cardiac autonomic control further link COPD and HF pathophysiology, emphasizing the need for comprehensive cardiovascular assessment., Objective: To investigate a cardiovascular profile in patients hospitalized with exacerbation COPD(ECOPD) in coexistence with HF compared with isolated diseases., Methods: A cross-sectional study including patients diagnosed with ECOPD and decompensated HF, approached between 24 and 48 h after hospital admission. Assessments included: endothelial function by brachial artery flow-mediated vasodilation(FMD); hemodynamic through analysis of pulse wave and arterial stiffness by carotid-femoral pulse wave velocity(cfPWV) and cardiac autonomic modulation(CAM) by heart rate variability(HRV)., Results: The mean FMD was 4.45 %, indicating endothelial dysfunction in all patients. Date is present in mean(confidence interval) sequency COPD(n = 12), COPD-HF(n = 21) and HF(n = 21). FMD: 5.47(3.96-6.91); 2.66(0.09-3.48); 4.60(2.30-6.43) p < 0.01. However, COPD-HF had worse FMD. Arterial stiffens (AIx: 29.0(19.0-42.6); 34.6(24.3-43.2); 14.5(8.0-24.0)p < 0.01; cfPWV: (6.5(5.4-7.2); 7.7(7.0-8.5); 6.0(5.0-6.5)); COPD-HF also showed greater activation of the sympathetic nervous system compared to patients with isolated diseases (PNS: 1.32(-2.53 to -0.62); -2.33(-2.60 to -2.12); -1.32(-1.42 to -1.01) p < 0.01; SNS: 3.50(1.40-8.55); 7.11(5.70-8.29); 2.32(1.78-5.01) p < 0.01). In addition, rMSSD, NN 50 , pNN 50 , and TINN also indicate worse CAM in the COPD-HF group compared to isolated diseases., Conclusion: During hospitalization, the worst impairment in vascular function and cardiac autonomic modulation were found in patients with COPD and HF comorbidity compared to the isolated diseases(HF or COPD)., Competing Interests: Declaration of competing interest All authors declare no conflicts of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Flow-diverter stents offer clinicians an effective solution for treating intracranial aneurysms, especially in cases where other devices may be unsuitable. However, strongly deviating success rates among different centres, manufacturers, and aneurysm phenotypes highlight the need for better in-situ studies of these devices. To support research in this area, virtual stenting algorithms have been proposed that, combined with computational fluid dynamics, provide insights into the hemodynamic alterations induced by the device. Yet, many existing algorithms rely on uncertain parameters, such as the forces applied during operation, fail to predict the length of the device after deployment, or lack robust validation steps, raising concerns about their reliability. Therefore, we developed a robust deployment technique that builds upon the geometrical features of the vessel and includes advancements from previous works. The algorithm is detailed and validated against literature examples, in-vitro experiments, and patient data, achieving a mean angular error below 5° in the latter. Furthermore, we describe and demonstrate how the deployed device can be embedded in a computational mesh using open-source tools and anisotropic meshing routines., Competing Interests: Declaration of competing interest None declared., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: The effective management of trauma patients necessitates efficient triaging, timely activation of Massive Blood Transfusion Protocols (MTP), and accurate prediction of in-hospital outcomes. Machine learning (ML) algorithms have emerged as up-and-coming tools in the domains of optimizing triage decisions, improving intervention strategies, and predicting clinical outcomes, consistently outperforming traditional methodologies. This study aimed to develop, assess, and compare several ML models for the triaging processes, activation of MTP, and mortality prediction., Methods: In a 10-year retrospective study, the predictive capabilities of seven ML models for trauma patients were systematically assessed using on-admission patients' hemodynamic data. All patient's data were randomly divided into training (80 %) and test (20 %) sets. Employing Python for data preprocessing, feature scaling, and model development, we evaluated K-Nearest Neighbors (KNN), Logistic Regression (LR), Decision Tree (DT), Support Vector Machines (SVM) with RBF kernels, Random Forest (RF), Extreme Gradient Boosting (XGBoost), and Artificial Neural Network (ANN). We employed various imputation techniques and addressed data imbalance through down-sampling, up-sampling, and synthetic minority for the over-sampling technique (SMOTE). Hyperparameter tuning, coupled with 5-fold cross-validation, was performed. The evaluation included essential metrics like sensitivity, specificity, F1 score, accuracy, Area Under the Receiver Operating Curve (AUC ROC), and Area Under the Precision recall Curve (AUC PR), ensuring robust predictive capability., Result: This study included 17,390 adult trauma patients; of them, 19.5 % (3385) were triaged at a critical level, 3.8 % (664) required MTP, and 7.7 % (1335) died in the hospital. The model's performance improved using imputation and balancing techniques. The overall models demonstrated notable performance metrics for predicting triage, MTP activation, and mortality with F1 scores of 0.75, 0.42, and 0.79, sensitivities of 0.73, 0.82, and 0.9, and AUC ROC values of 0.89, 0.95 and 0.99 respectively., Conclusion: Machine learning, especially RF models, effectively predicted trauma triage, MTP activation, and mortality. Featured critical hemodynamic variables include shock indices, systolic blood pressure, and mean arterial pressure. Therefore, models can do better than individual parameters for the early management and disposition of patients in the ED. Future research should focus on creating sensitive and interpretable models to enhance trauma care., Competing Interests: Declaration of competing interest All the authors have nothing to disclose and no conflict of interest. The Authors did not use AI and AI-assisted technologies in the writing process of this manuscript., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objectives: Cerebral arteriovenous malformations (AVMs) present complex neurovascular challenges, characterized by direct arteriovenous connections that disrupt normal brain blood flow dynamics. Traditional lumped parameter models (LPMs) offer a simplified angioarchitectural representation of AVMs, yet often fail to capture the intricate structure within the AVM nidus. This research aims at refining our understanding of AVM hemodynamics through the development of patient-specific LPMs utilizing three-dimensional (3D) medical imaging data for enhanced structural fidelity., Methods: This study commenced with the meticulous delineation of AVM vascular architecture using threshold segmentation and skeletonization techniques. The AVM nidus's core structure was outlined, facilitating the extraction of vessel connections and the formation of a detailed fistulous vascular tree model. Sampling points, spatially distributed and derived from the pixel intensity in imaging data, guided the construction of a complex plexiform tree within the nidus by generating smaller Y-shaped vascular formations. This model was then integrated with an electrical analog model to enable precise numerical simulations of cerebral hemodynamics with AVMs., Results: The study successfully generated two distinct patient-specific AVM networks, mirroring the unique structural and morphological characteristics of the AVMs as captured in medical imaging. The models effectively represented the intricate fistulous and plexiform vessel structures within the nidus. Numerical analysis of these models revealed that AVMs induce a blood shunt effect, thereby diminishing blood perfusion to adjacent brain tissues., Conclusion: This investigation enhances the theoretical framework for AVM research by constructing patient-specific LPMs that accurately reflect the true vascular structures of AVMs. These models offer profound insights into the hemodynamic behaviors of AVMs, including their impact on cerebral circulation and the blood steal phenomenon. Further incorporation of clinical data into these models holds the promise of deepening the theoretical comprehension of AVMs and fostering advancements in the diagnosis and treatment of AVMs., Competing Interests: Declaration of competing interest The authors would like to declare on behalf of the co-authors that the work described was original research that has not been published previously, and not under consideration for publication elsewhere, in whole or in part. No conflict of interest exists in the submission of this manuscript, and the manuscript is approved by all authors for publication., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Introduction: Early mobilization benefits critically ill patients, but concerns persist, especially in neurologic intensive care unit patients with acute brain injuries. This study assesses early mobility's impact on cerebrovascular autoregulation (CA) and systemic hemodynamics., Methods: This single-center retrospective study focused on adult neurologic intensive care unit patients undergoing passive cycle ergometry. Data were collected from December 2020 to April 2022. Physical therapists conducted sessions using a standardized protocol, monitoring mean arterial blood pressure (MAP) and intracranial pressure (ICP). The Pressure Reactivity Index (PRx) was calculated as a measure of CA. Statistical analysis included mixed models and repeated measures ANOVA., Results: Eleven patients undergoing continuous physiologic monitoring and early mobility were included, primarily with subarachnoid hemorrhage or intracranial hemorrhage. Median time to protocol initiation was 4 days, with two patients discontinuing due to hemodynamic disturbances. Over a total of 11-hours of neuromonitoring data, passive cycling demonstrated a significant reduction in heart rate (HR), MAP, and ICP across different rotations per minute (RPM) settings compared to baseline. No significant alterations in PRx or cerebral perfusion pressure (CPP) were noted at various RPM levels. However, a significant difference in PRx emerged between patients who completed the protocol and those who did not, particularly at 10 RPM., Discussion: This study offers preliminary insights into the impact of early mobility on CA in acute brain injured patients. While passive cycling demonstrates promise in preserving cerebral hemodynamics, its tolerability may not be uniform across all brain-injured patients. These findings highlight the need to determine optimal early mobilization timing and intensity in this population, emphasizing the necessity for larger prospective studies to validate these findings and inform clinical practice., Details: This manuscript complies with all instructions to the authors. All coauthors meet the authorship requirements and have reviewed and approved the contents of the manuscript. The manuscript has not been published totally or partly, accepted for publication, or under editorial review for publication elsewhere. We have no conflicts of interest to disclose. STROBE checklist was reviewed prior to the submission of this paper. The manuscript adheres to ethical guidelines and was approved by Cleveland Clinic's institutional research board for retrospective study. There is no funding to disclose for this study., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: The authors aim to investigate the effect of music on hemodynamic fluctuations during induction of general anesthesia and reducing preoperative anxiety for women who underwent elective non-cardiac surgery., Methods: It is a multicenter, double-blind, randomized, parallel-group clinical trial. Patients were randomized 1:1 to either a Music Intervention group (MI) or a Control group (Control). The MI participants listened to their preferred music for more than 30 minutes in the waiting area. The State-Trait Anxiety Inventory (STAI) was used to measure anxiety levels in the groups, and hemodynamic parameters (Heart Rate [HR], Mean Arterial Pressure [MAP]) were continuously recorded before induction (T0), at loss of consciousness (T1), immediately before intubation (T2), and after intubation (T3). Intubation-related adverse events were also recorded. The primary outcome was the incidence of MAP changes more than 20 % above baseline during T0-T2., Results: A total of 164 patients were included in the final analyses. The incidence of MAP instability during T0-T2 was lower in the MI, and the 95 % Confidence Interval for the rate difference demonstrated the superiority of MI. HR instability was less frequent in MI participants both in T0-T2 and T2-T3. The overall incidence of preoperative anxiety was 53.7 % (88/164). After the music intervention, the mean score of STAI was significantly lower in the MI than in the Control, with a between-group difference of 8.01., Conclusions: Preoperative music intervention effectively prevented hemodynamic instability during anesthesia induction and significantly reduced preoperative anxiety in women undergoing elective non-cardiac surgery., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2024. Published by Elsevier España, S.L.U.)

Background: Physics-informed neural networks (PINNs) have emerged as a powerful tool for solving inverse problems, especially in cases where no complete information about the system is known and scatter measurements are available. This is especially useful in hemodynamics since the boundary information is often difficult to model, and high-quality blood flow measurements are generally hard to obtain., Methods: In this work, we use the PINNs methodology for estimating reduced-order model parameters and the full velocity field from scatter 2D noisy measurements in the aorta. Two different flow regimes, stationary and transient were studied., Results: We show robust and relatively accurate parameter estimations when using the method with simulated data, while the velocity reconstruction accuracy shows dependence on the measurement quality and the flow pattern complexity. Comparison with a Kalman filter approach shows similar results when the number of parameters to be estimated is low to medium. For a higher number of parameters, only PINNs were capable of achieving good results., Conclusion: The method opens a door to deep-learning-driven methods in the simulations of complex coupled physical systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objective: High-resolution magnetic resonance imaging (HR-MRI) can provide valuable insights into the evaluation of vascular pathological conditions, and 3D digital subtraction angiography (3D-DSA) offers clear visualization of the vascular morphology and hemodynamics. This study aimed to investigate the potential of a multimodal method to treat unruptured vertebral artery dissection aneurysms (u-VADAs) by fusing image data from HR-MRI and 3D-DSA., Methods: This observational study enrolled 5 patients diagnosed with u-VADAs, who were scheduled for interventional treatment. The image data of HR-MRI and 3D-DSA were merged by geometry software, resulting in a multimodal model. Quantified values of aneurysm wall enhancement (AWE), wall shear stress (WSS), neck velocity, inflow volume, intra-stent flow velocity (ISvelocity), and intra-aneurysmal velocity (IAvelocity) were calculated from the multimodal method., Results: We found the actual lengths of u-VADAs in the multimodal model were longer than the 3D-DSA model. We formulated surgical plannings based on the WSS, IA velocity, and neck velocity. The post-operative value of IAvelocity, neck velocity, and follow-up quantified values of AWE were decreased compared with the pre-operative condition. After that, u-VADAs were complete occlusion in four patients and near-complete occlusion in one patient during the 6th-month follow-up after surgery., Conclusion: The multidimensional method combining HR-MRI with 3D-DSA may provide more valuable information for treating VADAs, with the potential to develop effective surgical planning., (Copyright © 2024. Published by Elsevier B.V.)