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Pump is a vital component for expelling the perfusate in small animal isolated organ normothermic machine perfusion (NMP) systems whose flexible structure and rhythmic contraction play a crucial role in maintaining perfusion system homeostasis. However, the continuous extrusion forming with the rigid stationary shaft of the peristaltic pumps can damage cells, leading to metabolic disorders and eventual dysfunction of transplanted organs. Here, we developed a novel biomimetic blood‐gas system (BBGs) for preventing cell damage. This system mimics the cardiac cycle and features an adjustable inspiratory‐to‐expiratory (IE) ratio to mitigate acidosis caused by continuous oxygen inhalation. In our study, adipose stem cells (ADSCs) were cultured within the circulatory system for 10 min, 2, and 4 h. Compared to the peristaltic pump, the BBGs significantly reduced cell apoptosis and morphological injury while enhancing cell proliferation and adhesion. Additionally, when the supernatant from ADSCs was introduced to LPS‐induced macrophages for 24 h, the BBGs group demonstrated a more pronounced anti‐inflammatory effect, characterized by reduced M1 macrophage expression. Besides, with isolated rat livers from donation after circulatory death (DCD) perfusion with ADSCs for 6 h by the BBGs, we detected fewer apoptotic cells and a reduced inflammatory response, evidenced by down‐regulated TNF‐α expression. The development of BBGs demonstrates the feasibility of recreating physiological liquid–gas circulation in vitro, offering an alternative platform for isolated organ perfusion, especially for applications involving cell therapy. [ABSTRACT FROM AUTHOR]

Introduction: Ventricular assist devices represent a treatment option for patients with advanced heart failure, offering control over various haemodynamic variables. Similarly, the prescription of exercise within a cardiac rehabilitation programme for heart failure patients is recommended to reduce symptoms, and hospitalisations, improve cardiorespiratory fitness, and increase exercise tolerance. Therefore, exercise prescription can impact those with ventricular assist devices. Given the limited evidence on exercise-based cardiac rehabilitation programmes for this population, this review aims to describe the most commonly used strategies and their health benefits when physical exercise is included in a cardiac rehabilitation programme for patients with ventricular assist devices. Materials and methods: An exploratory review was conducted through searches in the databases: PubMed, SCOPUS, PeDro, and ScienceDirect. The search was limited to studies published between 2013 and 2023. Filters were applied independently by title, abstract, and full text. The included articles were analysed based on the description of the types of cardiac rehabilitation strategies used in patients with ventricular assist devices. Results: Seven articles were included. Each programme employed a cardiopulmonary exercise test before prescribing physical exercise. The most commonly used strategy was aerobic exercise, predominantly high-intensity interval training (HIIT) with intensities close to 90% of peak VO2, followed by continuous moderate-intensity exercise. Limb strength exercises were included in three programmes. Conclusions: The analysed literature suggests that cardiac rehabilitation in patients with ventricular assist devices is safe and can provide benefits in cardiorespiratory fitness and exercise tolerance. High-intensity interval training is identified as an appropriate strategy for achieving results, offering short-term improvements. [ABSTRACT FROM AUTHOR]

A 70-year-old man with dilated cardiomyopathy underwent left ventricular assist device (LVAD) implantation, using a HeartWare ventricular assist device, as a bridge to candidacy. After 26 months, computed tomography (CT) angiography indicated stenosis in the LVAD outflow graft; however, the patient was asymptomatic, prompting a decision to manage his condition with close monitoring. Ten months later, the patient presented with dizziness and low-flow alerts. Subsequent CT angiography revealed a critical obstruction involving the entire LVAD outflow graft. The patient underwent emergency surgery, during which an organized seroma causing the graft obstruction was found between a wrapped expanded polytetrafluoroethylene (ePTFE) graft and a Dacron outflow graft. The covering of the outflow graft was removed, along with the organized seroma. Following removal of the ePTFE wrap and decompression of the outflow graft, normal LVAD flow was reestablished. The practice of wrapping the outflow graft with synthetic material, commonly done to facilitate later redo sternotomy, may pose a risk for outflow graft obstruction.

Abstract Background Values are broadly understood to have implications for how individuals make decisions and cope with serious illness stressors, yet it remains uncertain how patients and their family and friend caregivers discuss, reflect upon, and act on their values in the post-left ventricular assist device (LVAD) implantation context. This study aimed to explore the values elicitation experiences of patients with an LVAD in the post-implantation period. Methods Qualitative descriptive study of LVAD recipients. Socio-demographics and patient resource use were analyzed using descriptive statistics and semi-structured interview data using thematic analysis. Adult (> 18 years) patients with an LVAD receiving care at an outpatient clinic in the Southeastern United States. Results Interviewed patients (n = 27) were 30–76 years, 59% male, 67% non-Hispanic Black, 70% married/living with a partner, and 70% urban-dwelling. Three broad themes of patient values elicitation experiences emerged: 1) LVAD implantation prompts deep reflection about life and what is important, 2) patient values are communicated in various circumstances to convey personal goals and priorities to caregivers and clinicians, and 3) patients leverage their values for strength and guidance in navigating life post-LVAD implantation. LVAD implantation was an impactful experience often leading to reevaluation of patients’ values; these values became instrumental to making health decisions and coping with stressors during the post-LVAD implantation period. Patient values arose within broad, informal exchanges and focused, decision-making conversations with their caregiver and the healthcare team. Conclusions Clinicians should consider assessing the values of patients post-implantation to facilitate shared understanding of their goals/priorities and identify potential changes in their coping.

It is known that examining turbulence effects on medical devices has an important effect in design and optimization of blood-contacting devices. CFD has been commonly used on prosthetic heart valves, stents, and Ventricular Assist Devices (VADs) in both the design process and also on hemodynamics of the flow characteristics. In this study, flows in the FDA nozzle were modeled to examine Reynolds stresses in the whole domain. The flow behavior was determined by applying the Reynolds-Averaged Navier-Stokes model of turbulence (k-ω SST) to simulate five distinctive experimental cases in the nozzle taken from the literature. The Reynolds stress frequencies are determined for the five different experimental conditions. Results showed that the highest velocity case (corresponding throat Reynolds number of 6500) has much higher Reynolds stresses with a high number of frequencies. However, the lowest velocity case has very small Reynolds numbers in a very high frequency. When different parts of the nozzle were examined, the Reynolds stress values showed more fluctuations for the higher velocities and more regular profiles for the lower velocity cases. [ABSTRACT FROM AUTHOR]

Introduction: The use of veno‐arterial extracorporeal membrane oxygenation (VA‐ECMO) as a direct bridge to heart transplantation (BTT) is not common in adults worldwide. BTT with ECMO is associated with increased early/mid‐term mortality compared with other interventions. In low‐ and middle‐income countries (LMIC), where no other type of short‐term mechanical circulatory support is available, its use is widespread and increasingly used as rescue therapy in patients with cardiogenic shock (CS) as a direct bridge to heart transplantation (HT). Objective: To assess the outcomes of adult patients using VA‐ECMO as a direct BTT in an LMIC and compare them with international registries. Methods: We conducted a single‐center study analyzing consecutive adult patients requiring VA‐ECMO as BTT due to refractory CS or cardiac arrest (CA) in a cardiovascular center in Argentina between January 2014 and December 2022. Survival and adverse clinical events after VA‐ECMO implantation were evaluated. Results: Of 86 VA‐ECMO, 22 (25.5%) were implanted as initial BTT strategy, and 52.1% of them underwent HT. Mean age was 46 years (SD 12); 59% were male. ECMO was indicated in 81% for CS, and the most common underlying condition was coronary artery disease (31.8%). Overall, in‐hospital mortality for VA‐ECMO as BTT was 50%. Survival to discharge was 83% in those who underwent HT and 10% in those who did not, p <.001. In those who did not undergo HT, the main cause of death was hemorrhagic complications (44%), followed by thrombotic complications (33%). The median duration of VA‐ECMO was 6 days (IQR 3‐16). There were no differences in the number of days on ECMO between those who received a transplant and those who did not. In the Spanish registry, in‐hospital survival after HT was 66.7%; the United Network of Organ Sharing registry estimated post‐transplant survival at 73.1% ± 4.4%, and in the French national registry 1‐year posttransplant survival was 70% in the VA‐ECMO group. Conclusions: In adult patients with cardiogenic shock, VA‐ECMO as a direct BTT allowed successful HT in half of the patients. HT provided a survival benefit in listed patients on VA‐ECMO. We present a single center experience with results comparable to those of international registries. [ABSTRACT FROM AUTHOR]

OBJECTIVES This study aims to explore characteristics and clinical outcomes of patients with congenital heart disease (CHD) in the European Registry for Patients with Mechanical Circulatory Support (EUROMACS). METHODS This is a retrospective study of EUROMACS participants receiving MCS as bridge-to-transplant, possible bridge-to-transplant, or rescue therapy/bridge-to-recovery from 2011 to 2023 (n  = 5340). Adult and paediatric cohorts were analysed separately. The primary outcome was mortality on MCS; secondary outcomes included recovery, transplant and complications including bleeding, cerebrovascular events, and sepsis. RESULTS Among adult patients, mortality at 1-year was 33.3% among the CHD cohort vs 22.1% in the non-CHD cohort. Adult CHD patients had higher hazards of mortality within the first year after MCS implantation [hazard ratios 1.98, 95% confidence interval (CI) 1.35–2.91, P  < 0.001] and bleeding events (subdistribution hazard ratios 2.10, 95% CI 1.40–3.16, P  < 0.001) compared with non-CHD patients. Both associations remained significant after accounting for multiple mediators. Among paediatric patients, mortality at 1 year was 22.1% in the CHD cohort vs 17.3% in the non-CHD cohort (hazard ratios 1.39, 95% CI 0.83–2.32, P  = 0.213). CONCLUSIONS Adult and paediatric patients with CHD on MCS have higher adverse event risk compared with non-CHD MCS patients, though children did not have greater risk of mortality. As the number of CHD patients requiring advanced heart failure management continues to grow, these findings can enhance informed decision-making. Clinical trial registration number Registry name: EUROMACS. [ABSTRACT FROM AUTHOR]

Despite the high prevalence of sleep disturbance in the heart failure population, information about its consequence on daytime function in patients with left-ventricular assist devices (LVADs) is limited. This study examined the nighttime and daytime sleep patterns and changes from pre-implant to 6 months post-implant. This study included 32 LVAD patients. Demographics, nighttime and daytime sleep variables were collected pre-implant and at 1, 3, and 6 months post-implant. Wrist actigraphy and self-report questionnaires measured objective and subjective sleep, respectively. Objective nighttime sleep data were sleep efficiency (SE), sleep latency (SL), total sleep time (TST), wake after sleep onset (WASO), and sleep fragmentation (SF). Objective daytime sleep data were nap times. Self-reported Subjective Sleep Quality Scale (SSQS) and Stanford Sleepiness Scale (SSS) were subjective measures. Increased SF and WASO scores and decreased TST and SE scores were found pre-LVAD implant, indicative of poor sleep quality. TST, SE, naptime and SSQS scores were higher at 3 and 6 months post-implant compared to baseline. Decreases in TST and SF scores were observed at 3 and 6 months post-implant along with increases in SSS scores. Increasing SSS scores and decreasing overall scores from pre- and up to 6 months post-implant suggest improvement in daytime function. This study provides information on sleep-daytime function in the LVAD patient population. Improvements in daytime sleepiness do not imply "good" sleep quality, consistent with the extant knowledge in LVAD literature. Future investigations should elucidate the mechanism by which sleep-daytime function influences quality of life. [ABSTRACT FROM AUTHOR]

Background: Values are broadly understood to have implications for how individuals make decisions and cope with serious illness stressors, yet it remains uncertain how patients and their family and friend caregivers discuss, reflect upon, and act on their values in the post-left ventricular assist device (LVAD) implantation context. This study aimed to explore the values elicitation experiences of patients with an LVAD in the post-implantation period. Methods: Qualitative descriptive study of LVAD recipients. Socio-demographics and patient resource use were analyzed using descriptive statistics and semi-structured interview data using thematic analysis. Adult (> 18 years) patients with an LVAD receiving care at an outpatient clinic in the Southeastern United States. Results: Interviewed patients (n = 27) were 30–76 years, 59% male, 67% non-Hispanic Black, 70% married/living with a partner, and 70% urban-dwelling. Three broad themes of patient values elicitation experiences emerged: 1) LVAD implantation prompts deep reflection about life and what is important, 2) patient values are communicated in various circumstances to convey personal goals and priorities to caregivers and clinicians, and 3) patients leverage their values for strength and guidance in navigating life post-LVAD implantation. LVAD implantation was an impactful experience often leading to reevaluation of patients' values; these values became instrumental to making health decisions and coping with stressors during the post-LVAD implantation period. Patient values arose within broad, informal exchanges and focused, decision-making conversations with their caregiver and the healthcare team. Conclusions: Clinicians should consider assessing the values of patients post-implantation to facilitate shared understanding of their goals/priorities and identify potential changes in their coping. [ABSTRACT FROM AUTHOR]

Mechanical circulatory support is an increasingly important strategy for the treatment of a subset of patients with acute heart failure. Use of extracorporeal circuits with pumps and oxygenators to augment cardiac function can be immediately lifesaving, whereas implantable therapies can allow patients, with advanced heart disease, to resume near normal lives. Options for mechanical support are expanding, with long-term prognosis improving as devices become more sophisticated and complication rates fall. The perioperative management of such patients is reliant on complex specialist pathways and effective multidisciplinary decision-making. Critical care considerations for mechanical circulatory support are wide-ranging, and an understanding of the underlying physiology, device circuitry, anticoagulation, haemostasis, invasive monitoring and transoesophageal echocardiography is essential. [ABSTRACT FROM AUTHOR]

Thrombosis is the main reason for the failure of ventricular assist devices (VADs). It has been acknowledged that the platelet activation induced by the nonphysiological blood flow leads to the increased thrombotic risk. However, due to the complicated influence of the VADs' flow field and the difficulty in real‐time in situ observation, the mechanisms and process of thrombus formation in VADs remain unclear. In this work, the process of thrombus formation in VADs in vitro experiments is observed. The thrombus is found to form on the middle of the inlet guide vanes first and it is mainly caused by the immediate activation of platelets induced by the high shear rate of the flow field around the vanes and also affected by the rotation of the impeller. Then, subsequent thrombus is found in the tail of guide vanes and around the axle journal, where the blood flow is stagnated and the platelets are activated by the accumulated bioagonists. These findings clarify that the thrombus formed on the inlet guide vanes and the axle journal are dominated by two different mechanisms. This work provides unique insights into the initial formation of the thrombus on VADs and helps to reduce the thrombotic risk. [ABSTRACT FROM AUTHOR]

Background: The reactivity of blood with non‐endothelial surface is a challenge for long‐term Ventricular Assist Devices development, usually made with pure titanium, which despite of being inert, low density and high mechanical resistance it does not avoid the thrombogenic responses. Here we tested a modification on the titanium surface with Laser Induced Periodic Surface Structures followed by Diamond Like Carbon (DLC) coating in different thicknesses to customize the wettability profile by changing the surface energy of the titanium. Methods: Four different surfaces were proposed: (1) Pure Titanium as Reference Material (RM), (2) Textured as Test Sample (TS), (3) Textured with DLC 0.3μm as (TSA) and (4) Textured with 2.4μm DLC as (TSB). A single implant was positioned in the abdominal aorta of Wistar rats and the effects of hemodynamic interaction were evaluated without anticoagulant drugs. Results: After twelve weeks, the implants were extracted and subjected to qualitative analysis by Scanning Electron Microscopy under low vacuum and X‐ray Energy Dispersion. The regions that remained in contact with the wall of the aorta showed encapsulation of the endothelial tissue. TSB implants, although superhydrophilic, have proven that the DLC coating inhibits the adhesion of biological material, prevents abrasive wear and delamination, as observed in the TS and TSA implants. Pseudo‐ neointimal layers were heterogeneously identified in higher concentration on Test Surfaces. [ABSTRACT FROM AUTHOR]

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The characterization of intraventricular flow is critical to evaluate the efficiency of fluid transport and potential thromboembolic risk but challenging to measure directly in advanced heart failure (HF) patients with left ventricular assist device (LVAD) support. The study aims to validate an in-house mock loop (ML) by simulating specific conditions of HF patients with normal and prosthetic mitral valves (MV) and LVAD patients with small and dilated left ventricle volumes, then comparing the flow-related indices result of vortex parameters, residence time (RT), and shear-activation potential (SAP). Patient-specific inputs for the ML studies included heart rate, end-diastolic and end-systolic volumes, ejection fraction, aortic pressure, E/A ratio, and LVAD speed. The ML effectively replicated vortex development and circulation patterns, as well as RT, particularly for HF patient cases. The LVAD velocity fields reflected altered flow paths, in which all or most incoming blood formed a dominant stream directing flow straight from the mitral valve to the apex. RT estimation of patient and ML compared well for all conditions, but SAP was substantially higher in the LVAD cases of the ML. The benchtop system generated comparable and reproducible hemodynamics and fluid dynamics for patient-specific conditions, validating its reliability and clinical relevance. This study demonstrated that ML is a suitable platform to investigate the fluid dynamics of HF and LVAD patients and can be utilized to investigate heart-implant interactions. [ABSTRACT FROM AUTHOR]

Background: Short‐term continuous flow (STCF) ventricular assist devices (VADs) are utilized in adults with cardiogenic shock; however, mortality remains high. Previous studies have found that high pre‐operative MELD‐XI scores in durable VAD patients are associated with mortality. The use of the MELD‐XI score to predict outcomes in STCF‐VAD patients has not been explored. We sought to determine the relationship between MELD‐XI and outcomes in adults with STCF‐VADs. Methods: This was a retrospective review of adults implanted with STCF‐VADs between 2009 and 2019. Receiver operating characteristic (ROC) analysis was performed to predict outcomes and Kaplan–Meier analysis was done to assess survival. Results: Seventy‐nine patients were included with a median MELD‐XI score of 21.2 (IQR 13.5, 27.0). Patients with an unsuccessful wean from support (p < 0.001) or major post‐operative bleeding (p = 0.03) had significantly higher pre‐implant MELD‐XI scores. The optimal MELD‐XI cut‐point for mortality was 24.9 with 27.8 for major bleeding. Survival was worse among patients in the high‐risk MELD‐XI group, however, not statistically significant (p = 0.09). Prior ECMO support, but not MELD‐XI, was an independent predictor of unsuccessful wean (p = 0.03). Conclusions: Pre‐operative MELD‐XI score was a moderate predictor of unsuccessful wean with limited utility in predicting bleeding in patients on STCF‐VAD support. This scoring system may be useful in the clinical setting for pre‐implant risk stratification and counseling among patients and outcomes. [ABSTRACT FROM AUTHOR]

Abstract Thrombosis is the main reason for the failure of ventricular assist devices (VADs). It has been acknowledged that the platelet activation induced by the nonphysiological blood flow leads to the increased thrombotic risk. However, due to the complicated influence of the VADs’ flow field and the difficulty in real‐time in situ observation, the mechanisms and process of thrombus formation in VADs remain unclear. In this work, the process of thrombus formation in VADs in vitro experiments is observed. The thrombus is found to form on the middle of the inlet guide vanes first and it is mainly caused by the immediate activation of platelets induced by the high shear rate of the flow field around the vanes and also affected by the rotation of the impeller. Then, subsequent thrombus is found in the tail of guide vanes and around the axle journal, where the blood flow is stagnated and the platelets are activated by the accumulated bioagonists. These findings clarify that the thrombus formed on the inlet guide vanes and the axle journal are dominated by two different mechanisms. This work provides unique insights into the initial formation of the thrombus on VADs and helps to reduce the thrombotic risk.

Long-term mechanical circulatory support by a left ventricular assist device (LVAD), with or without an additional temporary or long-term right ventricular (RV) support, is a life-saving therapy for advanced heart failure (HF) refractory to pharmacological treatment, as well as for both device and surgical optimization therapies. In patients with chronic non-ischemic cardiomyopathy (NICM), timely prediction of HF's transition into its end stage, necessitating life-saving heart transplantation or long-term VAD support (as a bridge-to-transplantation or destination therapy), remains particularly challenging, given the wide range of possible etiologies, pathophysiological features, and clinical presentations of NICM. Decision-making between the necessity of an LVAD or a biventricular assist device (BVAD) is crucial because both unnecessary use of a BVAD and irreversible right ventricular (RV) failure after LVAD implantation can seriously impair patient outcomes. The pre-operative or, at the latest, intraoperative prediction of RV function after LVAD implantation is reliably possible, but necessitates integrative evaluations of many different echocardiographic, hemodynamic, clinical, and laboratory parameters. VADs create favorable conditions for the reversal of structural and functional cardiac alterations not only in acute forms of HF, but also in chronic HF. Although full cardiac recovery is rather unusual in VAD recipients with pre-implant chronic HF, the search for myocardial reverse remodelling and functional improvement is worthwhile because, for sufficiently recovered patients, weaning from VADs has proved to be feasible and capable of providing survival benefits and better quality of life even if recovery remains incomplete. This review article aimed to provide an updated theoretical and practical background for those engaged in this highly demanding and still current topic due to the continuous technical progress in the optimization of long-term VADs, as well as due to the new challenges which have emerged in conjunction with the proof of a possible myocardial recovery during long-term ventricular support up to levels which allow successful device explantation. [ABSTRACT FROM AUTHOR]

Pulmonary hypertension (PH) is common in advanced heart failure and often improves quickly after left ventricular assist device (VAD) implantation or orthotopic heart transplantation (OHT), but long-term effects and outcomes are not well-described. This study evaluated PH persistence after VAD as destination therapy (VAD-DT), bridge to transplant (VAD-OHT), or OHTalone. The study constituted a retrospective review of patients who underwent VAD-DT (n = 164), VAD-OHT (n = 111), or OHT-alone (n = 138) at a single tertiary-care center. Right heart catheterization (RHC) data was collected pre-, post-intervention (VAD and/or OHT), and 1-year from final intervention (latest-RHC) to evaluate the longitudinal hemodynamic course of right ventricular function and pulmonary vasculature. PH (Group II and Group I) definitions were adapted from expert guidelines. All groups showed significant improvements in mean pulmonary artery pressure (mPAP), pulmonary artery wedge pressure (PAWP), cardiac output, and pulmonary vascular resistance (PVR) at each RHC with greatest improvement at post-intervention RHC (post-VAD or post-OHT). PH was reduced from 98% to 26% in VAD-OHT, 92% -49% in VAD-DT, and 76%-28% in OHT-alone from preintervention to latest-RHC. At latest-RHC mPAP remained elevated in all groups despite normalization of PAWP and PVR. VAD-supported patients exhibited suppressed pulmonary artery pulsatility index (PaPi < 3.7) with improvement only posttransplant at latest-RHC. Posttransplant patients with PH at latest- RHC (n = 60) exhibited lower survival (HR: 2.1 [95% CI: 1.3-3.4], p < 0.001). Despite an overall significant improvement in pulmonary pressures and PH proportion, a notable subset of patients exhibited PH post-intervention. Postintervention PH was associated with lower posttransplant survival. [ABSTRACT FROM AUTHOR]

In the present paper, we investigate how the reductions in shear stresses and pressure losses in microfluidic gaps are directly linked to the local characteristics of cell-free layers (CFLs) at channel Reynolds numbers relevant to ventricular assist device (VAD) applications. For this, detailed studies of local particle distributions of a particulate blood analog fluid are combined with wall shear stress and pressure loss measurements in two complementary set-ups with identical flow geometry, bulk Reynolds numbers and particle Reynolds numbers. For all investigated particle volume fractions of up to 5 % , reductions in the stress and pressure loss were measured in comparison to a flow of an equivalent homogeneous fluid (without particles). We could explain this due to the formation of a CFL ranging from 10 to 20 μ m. Variations in the channel Reynolds number between Re = 50 and 150 did not lead to measurable changes in CFL heights or stress reductions for all investigated particle volume fractions. These measurements were used to describe the complete chain of how CFL formation leads to a stress reduction, which reduces the apparent viscosity of the suspension and results in the Fåhræus–Lindqvist effect. This chain of causes was investigated for the first time for flows with high Reynolds numbers ( R e ∼ 100 ), representing a flow regime which can be found in the narrow gaps of a VAD. [ABSTRACT FROM AUTHOR]

Abstract Pulmonary hypertension (PH) is common in advanced heart failure and often improves quickly after left ventricular assist device (VAD) implantation or orthotopic heart transplantation (OHT), but long‐term effects and outcomes are not well‐described. This study evaluated PH persistence after VAD as destination therapy (VAD‐DT), bridge to transplant (VAD‐OHT), or OHT‐alone. The study constituted a retrospective review of patients who underwent VAD‐DT (n = 164), VAD‐OHT (n = 111), or OHT‐alone (n = 138) at a single tertiary‐care center. Right heart catheterization (RHC) data was collected pre‐, post‐intervention (VAD and/or OHT), and 1‐year from final intervention (latest‐RHC) to evaluate the longitudinal hemodynamic course of right ventricular function and pulmonary vasculature. PH (Group II and Group I) definitions were adapted from expert guidelines. All groups showed significant improvements in mean pulmonary artery pressure (mPAP), pulmonary artery wedge pressure (PAWP), cardiac output, and pulmonary vascular resistance (PVR) at each RHC with greatest improvement at post‐intervention RHC (post‐VAD or post‐OHT). PH was reduced from 98% to 26% in VAD‐OHT, 92%−49% in VAD‐DT, and 76%−28% in OHT‐alone from preintervention to latest‐RHC. At latest‐RHC mPAP remained elevated in all groups despite normalization of PAWP and PVR. VAD‐supported patients exhibited suppressed pulmonary artery pulsatility index (PaPi

Most of the existing hemolysis mechanism studies are carried out on the macro flow scale. They assume that the erythrocyte membranes with different loads will suffer the same damage, which obviously has limitations. Thus, exploring the hemolysis mechanism through the macroscopic flow field information is a tough challenge. In order to further understand the non-physiological shear hemolysis phenomenon at the cell scale, this study used the coarse-grained erythrocytes damage model at the mesoscopic scale based on the transport dissipative particle dynamics (tDPD) method. Combined with computational fluid dynamics the hemolysis of scalarized shear stress (1) in the clearance of "Impella 5.0" was evaluated under the Lagrange perspective and Euler perspective. The results from the Lagrange perspective showed that the change rate of scaled shear stress (...τ) was the most critical factor in damaging RBCs in the rotor region of "Impella 5.0 and other transvalvular micro-axial blood pumps. Then, we propose a dimensionless number Dk with time integration based on ...τ to evaluate hemolysis. The Dissipative particle dynamics simulation results are consistent with the Dk, evaluation results, so ...τ may be an important factor in the hemolysis of VADs. Finally, we tested the hemolysis of 30% hematocrit whole blood in the "Impella 5.0" shroud clearance from the Euler perspective. Relevant results indicate that because of the wall effect, the RBCs near the impeller side are more prone to damage, and most of the cytoplasm is also gathered at the rotor side. [ABSTRACT FROM AUTHOR]

Background: Left ventricular assist device (LVAD) implantation via thoracotomy has many potential advantages compared to conventional sternotomy, including improved inflow cannula (IFC) positioning. We compared the difference in IFC angles, postoperative, and long‐term outcomes for patients with LVADs implanted via thoracotomy and sternotomy. Methods: A single‐center, retrospective analysis of 14 patients who underwent thoracotomy implantation was performed and matched with 28 patients who underwent sternotomy LVAD implantations for a total of 42 patients. Inclusion required a minimum LVAD support duration of 30 days and excluded concomitant procedures. A postoperative CT‐chest was used to measure the angle the between the IFC and mitral valve in two‐dimensions and results were compared with three‐dimensional reconstruction using the same CT chest. Outcome data were extracted from medical records. Results: There was no significant difference in gender, INTERMACS score, BMI, or age between the two groups. Median cardiopulmonary bypass time was longer in the thoracotomy group compared to the sternotomy group, 107 min (86–122) versus 76 min (56–93), p < 0.01. 3D reconstructions revealed less deviation of the IFC away from the mitral valve in devices implanted via thoracotomy compared to sternotomy, median (IQR) angle 16.3° (13.9°–21.0°) versus 23.2° (17.9°–26.4°), p < 0.01. Rates of pump thrombosis, stroke, and gastrointestinal bleeding were not significantly different. Conclusions: Devices implanted via thoracotomy demonstrated less deviation away from mitral valve. However, there was no difference in morbidity between the two approaches. 3D reconstruction of the heart is an innovative technique to measure angulation and is clinically advantageous when compared to 2D imaging. [ABSTRACT FROM AUTHOR]

Objectives: We compared posttransplant outcomes between patients bridged from temporary mechanical circulatory support to durable left ventricular assist device before transplant (bridge-to-bridge [BTB] strategy) and patients bridged from temporary mechanical circulatory support directly to transplant (bridge-to-transplant [BTT] strategy). Methods: We identified adult heart transplant recipients in the Organ Procurement and Transplantation Network database between 2005 and 2020 who were supported with extracorporeal membrane oxygenation, intra-aortic balloon pump, or temporary ventricular assist device as a BTB or BTT strategy. Kaplan-Meier survival analysis and Cox regressions were used to assess 1-year, 5-year, and 10-year survival. Posttransplant length of stay and complications were compared as secondary outcomes. Results: In total, 201 extracorporeal membrane oxygenation (61 BTB, 140 BTT), 1385 intra-aortic balloon pump (460 BTB, 925 BTT), and 234 temporary ventricular assist device (75 BTB, 159 BTT) patients were identified. For patients supported with extracorporeal membrane oxygenation, intra-aortic balloon pump, or temporary ventricular assist device, there were no differences in survival between BTB and BTT at 1 and 5 years posttransplant, as well as 10 years posttransplant even after adjusting for baseline characteristics. The extracorporeal membrane oxygenation BTB group had greater rates of acute rejection (32.8% vs 13.6%; P = .002) and lower rates of dialysis (1.6% vs 21.4%; P

In the United States, about one million people are seen to visit the operating theater for cardiac surgery annually. However, nearly half of these visits result in complications such as renal, neurological, and cardiac injury of varying degrees. Historically, many mechanisms and approaches have been explored in attempts to reduce injuries associated with cardiac surgery and percutaneous procedures. Devices such as cardioplegia, mechanical circulatory support, and other methods have shown promising results in managing and preventing life-threatening cardiac-surgery-related outcomes such as heart failure and cardiogenic shock. Comparably, cardioprotective devices such as TandemHeart, Impella family devices, and venoarterial extracorporeal membrane oxygenation (VA-ECMO) have also been proven to show significant cardioprotection through mechanical support. However, their use as interventional agents in the prevention of hemodynamic changes due to cardiac surgery or percutaneous interventions has been correlated with adverse effects. This can lead to a rebound increased risk of mortality in high-risk patients who undergo cardiac surgery. Further research is necessary to delineate and stratify patients into appropriate cardioprotective device groups. Furthermore, the use of one device over another in terms of efficacy remains controversial and further research is necessary to assess device potential in different settings. Clinical research is also needed regarding novel strategies and targets, such as transcutaneous vagus stimulation and supersaturated oxygen therapy, aimed at reducing mortality among high-risk cardiac surgery patients. This review explores the recent advances regarding the use of cardioprotective devices in patients undergoing percutaneous procedures and cardiac surgery. [ABSTRACT FROM AUTHOR]

We aimed to describe recent trends in the use and outcomes of temporary mechanical circulatory support (MCS) as a bridge to heart transplantation (HTx) in Spain. Retrospective case-by-case analysis of 1,036 patients listed for emergency HTx while on temporary MCS in 16 Spanish institutions from January 1st, 2010 to December 31st, 2020. Patients were classified in 3 eras according to changes in donor allocation criteria (Era 1: January 2010/May 2014; Era 2: June 2014/May 2017; Era 3: June 2017/December 2020). Over time, the proportion of candidates listed with intra-aortic balloon pumps decreased (Era 1 = 55.9%, Era 2 = 32%, Era 3 = 0.9%; p < 0.001), while the proportion of candidates listed with surgical continuous-flow temporary VADs (Era 1 = 10.6%, Era 2 = 32%, Era 3 = 49.1%; p < 0.001) and percutaneous VADs (Era 1 = 0.3%, Era 2 = 6.3%; Era 3 = 17.2%; p < 0.001) increased. Rates of HTx increased from Era 1 (79.4%) to Era 2 (87.8%), and Era 3 (87%) (p = 0.004), while rates of death before HTx decreased (Era 1 = 17.7%; Era 2 = 11%, Era 3 = 12.4%; p = 0.037) Median time from listing to HTx increased in patients supported with intra-aortic balloon pumps (Era 1 = 8 days, Era 2 = 15 days; p < 0.001) but remained stable in other candidates (Era 1 = 6 days; Era 2 = 5 days; Era 3 = 6 days; p = 0.134). One-year post-transplant survival was 71.4% in Era 1, 79.3% in Era 2, and 76.5% in Era 3 (p = 0.112). Preoperative bridging with ECMO was associated with increased 1-year post-transplant mortality (adjusted HR=1.71; 95% CI 1.15-2.53; p = 0.008). During the period 2010 to 2020, successive changes in the Spanish organ allocation protocol were followed by a significant increase of the rate of HTx and a significant reduction of waiting list mortality in candidates supported with temporary MCS. One-year post-transplant survival rates remained acceptable. [ABSTRACT FROM AUTHOR]

Ventricular assist devices (VAD) have gained popularity in the pediatric population during recent years, as more and more children require a heart transplant due to improved palliation methods, allowing congenital heart defect patients and children with cardiomyopathies to live longer. Eventually, these children may require heart transplantation, and ventricular assist devices provide a bridge to transplantation in these cases. The FDA has so far approved two types of device: pulsatile and continuous flow (non-pulsatile), which can be axial and centrifugal. Potential eligible studies were searched in three databases: Medline, Embase, and ScienceDirect. Our endeavor retrieved 16 eligible studies focusing on five ventricular assist devices in children. We critically reviewed ventricular assist devices approved for pediatric use in terms of implant indication, main adverse effects, and outcomes. The main adverse effects associated with these devices have been noted to be thromboembolism, infection, bleeding, and hemolysis. However, utilizing left VAD early on, before end-organ dysfunction and deterioration of heart function, may give the patient enough time to recuperate before considering a more long-term solution for ventricular support. [ABSTRACT FROM AUTHOR]

Management of patients with end‐stage heart failure is still challenging. We report a case of idiopathic dilated cardiomyopathy who went through a challenging course. The case was presented as acute heart failure syndrome, which rapidly declined into cardiogenic shock and cardiac arrest that required an extracorporeal membrane oxygenator, then biventricular assist device implantation for circulatory support. The course was complicated with severe gastrointestinal bleeding and multiorgan failure until achieving full cardiac and organ recovery. The left ventricle ejection fraction improved from 10% to 50% at discharge. [ABSTRACT FROM AUTHOR]

Echocardiography (ECHO) is indispensable for evaluation of patients with terminal chronic heart failure (HF) who require transplantation or mechanical circulatory support by a left- or biventricular assist device (LVAD or BiVAD, respectively). In LVAD candidates, ECHO represents the first-line investigation necessary for a timely discovery of heart-related risk factors for potentially life-threatening postoperative adverse events, including identification of patients who necessitate a biventricular support. ECHO is also required for intraoperative guiding of VAD implantation and finding of the most appropriate setting of the device for an optimal ventricular unloading, postoperative surveillance of the VAD support, and monitoring of the RV changes in LVAD recipients. Thanks to the ECHO, which has decisively contributed to the proof that prolonged VAD support can facilitate cardiac reverse remodeling and functional improvement to levels which allow successful weaning of carefully selected patients from LVAD or BiVAD, the previous opinion that chronic nonischemic cardiomyopathy (NICMP) is irreversible could be refuted. In patients with normalized and stable right heart catheter-derived hemodynamic parameters obtained at short-term interruptions of VAD support, ECHO has proved able to predict post-weaning long-term freedom from HF recurrence in patients with pre-implant terminal chronic NICMP. The purpose of this article is to offer an actualized theoretical and practical support for clinicians engaged in this particularly challenging and topical issue especially due to the new practical aspects which have emerged in conjunction with the growing use of long-term ventricular assist devices as bridge-to-transplantation or as destination therapy, as well as the increasing evidence that, in some patients, such VAD can become a bridge-to-recovery, allowing the removal of the device after a longer support time. [ABSTRACT FROM AUTHOR]

• Transvalvular VADs implantation leads to aortic valve insufficiency. • The valve regurgitation caused by VADs implantation is controllable. • The whirling flow in the flow direction optimizes the stress distribution. • The whirling flow has little impact on VADs implantation. The implantation of ventricular assist devices (VADs) has become an important treatment option for patients with heart failure. Aortic valve insufficiency is a common complication caused by VADs implantation. Currently, there is very little quantitative research on the effects of transcatheter micro VADs or the intervention pumps on the aortic valves. In this study, the multi-component arbitrary Lagrange-Eulerian method is used to perform fluid-structure interaction simulations of the aortic valve model with and without intervention pumps. The effects of intervention pumps implantation on the opening area of the aortic valves, the stress distribution, and the flow characteristics are quantitatively analyzed. Statistical results are consistent with clinical guidelines and experiments. The implantation of intervention pumps leads to the valve insufficiency and causes weak valve regurgitation. In the short-term treatment, the valve regurgitation is within a controllable range. The distribution and variation of stress on the leaflets are also affected by intervention pumps. The whirling flow in the flow direction affects the closing speed of the aortic valves and optimizes the stress distribution of the valves. In the models with whirling flow, the effects of intervention pumps implantation on valve motion and stress distribution differ from those without whirling flow. However, the valve insufficiency and valve regurgitation caused by intervention pumps still exist in the models with whirling flow. Conventional artificial bioprosthetic valves have limited effectiveness in treating the valve diseases caused by intervention pumps implantation. This study quantitatively investigates the impact of intervention pumps on the aortic valves, and investigates the effect of blood rotation on the valve behavior, which is a gap in previous research. We suggest that in the short-term treatment, the implantation of intervention pumps has limited impact on aortic valves, caution should be exercised against valve regurgitation issues caused by intervention pumps. [ABSTRACT FROM AUTHOR]

Introduction: Left ventricular assist device (LVAD) insertion is an increasingly common intervention for patients with advanced heart failure; however, published literature on the emergency department (ED) presentation of this population is limited. The objective of this study was to characterize ED presentations of patients with LVADs with a focus on device-specific complications to inform provider education and preparation initiatives. Methods: This was a retrospective chart review of all patients with LVADs followed at an urban academic medical center presenting to the ED over a five-year period (July 1, 2009, to June 30, 2014). Two abstractors reviewed 45 randomly selected charts to standardize the abstraction process and establish a priori categories for reason for presentation to the ED. Remaining charts were then divided evenly for review by one of the two abstractors. Primary outcomes for this study were (1) frequency of and (2) reason for presentation to the ED by patients with LVADs. Results: Of 349 patients with LVADs identified, 143 (41.0%) had ED encounters during the study period. There were 620 total ED encounters, (range 1 to 32 encounters per patient, median=3, standard deviation=5.3). Among the encounters, 431 (69.5%) resulted in admission. The most common reasons for presentation were bleeding (e.g., gastrointestinal, epistaxis) (182, 29.4%); infection (127, 20.5%); heart failure exacerbation (68, 11.0%); pain (56, 9.0%); other (45, 7.3%); and arrhythmias (40, 6.5%). Fifty-two encounters (8.4%) were device-specific; these patients frequently presented with abnormal device readings (37, 6.0%). Interventions for device-specific presentations included anticoagulation regimen adjustment (16/52, 30.8%), pump exchange (9, 17.3%), and hardware repair (6, 11.5%). Pump thrombosis occurred in 23 cases (3.7% of all encounters). No patients required cardiopulmonary resuscitation or died in the ED. Conclusion: This is the largest study known to the investigators to report the rate of ED presentations of patients with LVADs and provide analysis of device-specific presentations. In patients who do have device-specific ED presentations, pump thrombosis is a common diagnosis and can present without device alarms. Specialized LVAD education and preparation initiatives for ED providers should emphasize the recognition and management of the most common and critical conditions for this patient population, which have been identified in this study as bleeding, infection, heart failure, and pump thrombosis.

A 55-year-old woman who had received an implantable left ventricular assist device 3 months earlier presented with dyspnea and a low-flow alarm of the device. Computed tomography and log-file analysis of the device system suggested inflow cannula obstruction. Since the patient had cardiogenic shock due to pump failure, venoarterial extracorporeal membrane oxygenation (ECMO) was initiated. With ECMO, surgical exchange of the pump was considered. However, the obstruction spontaneously resolved without surgical intervention. It turned out that an obstructive thrombus was washed out by rebooting the pump. Moreover, the thrombus was embolized in the patient’s left subclavian artery. The patient underwent heart transplantation 4 months after the pump obstruction accident and continued to do well.

Frailty is becoming an important component of health care outcomes in patients with a diagnosis of heart failure. A literature search was completed to determine whether a best practice guideline existed to assess frailty in patients who were considering ventricular assist device placement. The literature search revealed that best practice guidelines did not exist. A second comprehensive literature search was completed specifically for frailty including the definition, criteria, assessment, and outcomes. The studies revealed that there were challenges with defining frailty, the age of frailty, assessments tools, and study designs. Cardiologists are primarily interested in screening for frailty, but other physician specialty practices are interested in a frailty screening tool as well. This article discusses the inconsistent research studies and the need for a valid and reliable tool to assess for frailty. It is important that nurse leaders and those working with heart failure patients determine the best practice guidelines for assessing frailty. [ABSTRACT FROM AUTHOR]

Millions of American adults suffer from right heart failure (RHF), a condition associated with high rates of hospitalization, organ failure, and death. There is a multitude of etiologies and mechanisms that lead to RHF, often in a feedforward spiral of decline. The management of advanced cases of RHF can be particularly difficult. For patients who are refractory to the medical optimization of volume status, hemodynamic and pharmacologic support, and rhythm control, mechanical therapies may be warranted. Currently available mechanical assist devices for RHF include venoarterial extracorporeal oxygenation and right ventricular assist devices, both surgical and percutaneous. Each advanced therapy has its own potential advantages and limitations, and often is appropriate in different clinical contexts. In this review, the authors describe the pathophysiology and medical therapies for RHF and then focus on the different types of advanced therapies that currently exist to help inform medical decision-making for this complicated patient cohort. [ABSTRACT FROM AUTHOR]

We sought to characterize strokes in children with ventricular assist devices. Of 407 patients in the ACTION registry (4/1/18–5/3/2021), 45 (11%) experienced 52 strokes (45 ischemic and 7 hemorrhagic). Median time to stroke was 23.5 days and 19/52 (37%) occurred ≤ 10 days. Stroke rate was 0.09 and 0.63 strokes per patient-year for implantable continuous and paracorporeal devices, respectively. Patients with stroke were younger, more likely to have congenital heart disease and have been on extracorporeal membrane oxygenation at time of VAD. Based on these data, ACTION is now focused on decreasing strokes in these higher-risk patients with particular attention to the peri-implant period. [ABSTRACT FROM AUTHOR]

Ventricular assist device (VAD) infections are frequent causes of hospital readmission. The risk factors and optimal preventive strategies for such, including chronic suppressive antibiotics (CSA), remain uncertain. We performed a single-center, retrospective, observational cohort study assessing continuous flow VAD recipients who underwent implantation between 2008 and 2018 in Japan. From primary VAD infection (VADI), we followed the patients for recurrent infection, defined as relapsing VAD-specific (e.g., localized infections) or VAD-related (e.g., bacteremia) infections requiring hospital readmission. CSA was defined as the use of oral antimicrobial agents continued beyond initial antibiotic use until transplantation, VAD withdrawal, VADI recurrence, or death. Survival analysis was performed to identify risk factors for recurrent infection accounting for competing risks (e.g., deaths and transplants). Among 163 eligible patients, 76 patients had VADIs. The main causative organism in primary VADI was Staphylococcus aureus (63%, 48/76). Among them, 41 had recurrent infections, whereas 35 had none during the follow-up period (median, 335 days). Thirty-six patients received CSA for a median of 478 days. Although CSA was associated with a decreased risk of recurrent infection [adjusted sub-distribution hazard ratio (SHR), 0.40; 95% confidence interval (CI), 0.18-0.89; P = 0.03], this protective effect was observed only after primary VAD-specific infection (SHR, 0.28; 95% CI, 0.12-0.64; P < 0.01) but not after VAD-related infection. Surgical procedures during primary VADI were associated with an increased risk (SHR, 2.00; 95% CI, 1.10-3.66; P = 0.02). One patient had an adverse drug reaction. CSA may be an effective approach to limit relapsing VADIs following a primary VAD-specific infection with minimal adverse events., Importance: Ventricular assist device infections (VADIs) are a significant complication leading to hospital readmissions. However, the risk factors and optimal preventive strategies for VADI remain unclear. This study investigated the effectiveness of chronic suppressive antibiotic therapy in patients with VADI. We found that the use of chronic suppressive antibiotic therapy was associated with a reduction in the risk of VADI recurrence with few adverse reactions. Our findings suggest the potential benefit of chronic suppressive antibiotics in preventing infections in selected cases. Our findings are relevant for the management of patients with ventricular assist devices awaiting heart transplantation, providing valuable insights for clinical practice.

Artificial muscles enable the design of soft implantable devices which are poised to transform the way we mechanically support the heart today. Heart failure is a prevalent and deadly disease, which is treated with the implantation of rotary blood pumps as the only alternative to heart transplantation. The clinically used mechanical devices are associated with severe adverse events, which are reflected here in a comprehensive list of critical requirements for soft active devices of the future: low power, no blood contact, pulsatile support, physiological responsiveness, high cycle life, and less-invasive implantation. In this review, prior art in artificial muscles for their applicability in the short and long term is investigated and critically evaluated. The main challenges regarding the effectiveness, controllability, and implantability of recently proposed actuators are highlighted and the future perspectives for attachment, physiological responsiveness, durability, and biodegradability as well as equitable design considerations are explored., (© 2023 The Authors. Advanced Materials published by Wiley‐VCH GmbH.)

Dilated cardiomyopathy (DCM) is a prevalent heart muscle disease characterized by ventricular dilation and systolic dysfunction, leading to severe heart failure (HF) and often requiring heart transplantation (HTx). This systematic review aimed to synthesize information regarding the role of ventricular assist devices (VADs) in managing HF patients due to DCM. A comprehensive search was conducted across PubMed, Embase, Scopus, Web of Science, and Cochrane databases for studies published between 2014 and 2024. Inclusion criteria were studies involving adult patients with HF due to DCM treated with VADs. Exclusion criteria included non-human studies, pediatric populations, and non-peer-reviewed articles. Thirty-one studies met the inclusion criteria. The included studies demonstrated that the use of VADs in patients with DCM resulted in significant improvements in left ventricular ejection fraction (LVEF), myocardial fibrosis reduction, and reverse ventricular remodeling. Studies reported enhanced survival rates, reduced symptoms, and better quality of life. VADs served as a critical bridge to HTx and, in some cases, as long-term destination therapy. However, complications such as thrombus formation, anemia, and kidney failure were noted, emphasizing the need for vigilant monitoring and management. Continuous advancements in VAD technology and patient management protocols were found to be essential for optimizing outcomes. We conclude that VADs play a crucial role in managing advanced HF due to DCM by providing mechanical circulatory support, improving cardiac function, and enhancing patient survival and quality of life. Despite associated complications, VADs are invaluable for patients with severe HF, offering both immediate and long-term therapeutic benefits. Future research should focus on minimizing complications and further improving VAD technology to enhance patient outcomes., Competing Interests: Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, McBenedict et al.)

Medical advancements, particularly in ventricular assist devices (VADs), have notably advanced heart failure (HF) treatment, improving patient outcomes. However, challenges such as adverse events (strokes, bleeding and thrombosis) persist. Computational fluid dynamics (CFD) simulations are instrumental in understanding VAD flow dynamics and the associated flow-induced adverse events resulting from non-physiological flow conditions in the VAD.This study aims to validate critical CFD simulation parameters for accurate VAD simulations interacting with the cardiovascular system, building upon the groundwork laid by Hahne et al. A bidirectional coupling technique was used to model dynamic (pulsatile) flow conditions of the VAD CFD interacting with the cardiovascular system. Mesh size, time steps and simulation method (URANS, LES) were systematically varied to evaluate their impact on the dynamic pump performance (dynamic H - Q curve) of the HeartMate 3, aiming to find the optimal simulation configuration for accurately reproduce the dynamic H - Q curve. The new Overlapping Ratio (OR) method was developed and applied to quantify dynamic H - Q curves.In particular, mesh and time step sizes were found to have the greatest influence on the calculated pump performance. Therefore, small time steps and large mesh sizes are recommended to obtain accurate dynamic H - Q curves. On the other hand, the influence of the simulation method was not significant in this study. This study contributes to advancing VAD simulations, ultimately enhancing clinical efficacy and patient outcomes., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Thromboembolic complications still arise on blood contacting surfaces. Surface charge and topography influence the subsequent deposition of proteins and platelets, potentially leading to thrombi. Research showed a correlation of surface charge and nanoscale roughness, and a negative surface charge as well as a smooth surface finish are associated with lower thrombogenicity. The aim of this study was to compare the platelet adhesion on titanium with different nanoscale roughnesses and to examine if those roughness variations caused a change in surface charge. Titanium samples were polished and roughened to four different nanoscale roughness levels. Platelet adhesion (covered surface area (CSA), N  = 8) was tested in flow chambers with human whole blood using fluorescence imaging. ζ-potential was measured over a broad range of pH-values and interpolated to obtain the ζ-potential for pH Blood (7.4). Platelet adhesion tests were evaluated in terms of p -values and the Wilcoxon test effect size and the trend of the ζ-potential at pH Blood and the CSA was compared. R a -values ranged between 35 (polished) and 156 nm. Regarding platelet adhesion, the polished sample showed the lowest mean CSA with a medium or strong effect size compared to the roughened samples. The interpolated ζ-potentials for pH Blood follow a similar trend as the CSA, with the lowest ζ-potential measured for the polished surface. These findings suggest that the decreasing ζ-potential due to lower nanoscale roughness might be an additional explanation for the improved hemocompatibility besides the smoother topography., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Installing and developing a sophisticated control system to optimize left ventricular assist device (LVAD) pump speed to meet changes in metabolic demand is essential for advancing LVAD technology. This paper aims to design and implement a physiological control method for LVAD pumps to provide optimal cardiac output. The method is designed to adjust the pump speed by regulating the pump flow based on a predefined set point (operating point). The Frank–Starling mechanism technique was adopted to control the set point within a safe operating zone (green square), and it mimics the physiological demand of the patient. This zone is predefined by preload control lines, which are known as preload lines. A proportional–integral (PI) controller was utilized to control the operating point within safe limits to prevent suction or overperfusion. In addition, a PI type 1 fuzzy logic controller was designed and implemented to drive the LVAD pump. To evaluate the design method, rest, moderate, and exercise scenarios of heart failure (HF) were simulated by varying the hemodynamic parameters in one cardiac cycle. This evaluation was conducted using a lumped parameter model of the cardiovascular system (CVS). The results demonstrated that the proposed control method efficiently drives an LVAD pump under accepted clinical conditions. In both scenarios, the left ventricle pressure recorded 112 mmHg for rest and 55 mmHg for exercise, and the systematic flow recorded 5.5 L/min for rest and 1.75 L/min for exercise. [ABSTRACT FROM AUTHOR]