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ObjectiveFontan surgical planning involves designing grafts to perform optimized hemodynamic performance for the patient’s long-term health benefit. The uncertainty of post-operative boundary conditions (BC) and graft anastomisis displacements may significantly affect the optimized graft designs and lead to undesired outcomes, especially for hepatic flow distribution (HFD). We aim to develop a computation framework to automatically optimize patient-specific Fontan grafts with the maximized possibility of keeping the post-operative results within clinical acceptable thresholds.MethodsThe uncertainties of BC and anastomosis displacements were modeled by using Gaussian distributions according to prior research studies. By parameterizing the Fontan grafts, we built surrogate models of hemodynamic parameters by taking the design parameters and BC as inputs. A two-phased reliability-based robust optimization (RBRO) strategy was developed by combining deterministic optimization (DO) and optimization under uncertainty (OUU) to reduce the computation cost.ResultsWe evaluated the performance of the RBRO framework by comparing it with the DO method on four Fontan patient cases. The results showed that the surgical plans computed from the proposed method yield up to 79.2% improvement on the reliability of HFD than those from the DO method (p < 0.0001). The mean values of iPL and %WSS satisfied the clinically acceptable thresholds.ConclusionThis study demonstrated the effectiveness of our RBRO framework to address uncertainties of BC and anastomosis displacements for Fontan surgical planning.SignificanceThe technique developed in this paper demonstrates a significant improvement in the reliability of predicted post-operative outcomes for Fontan surgical planning. This planning technique is immediately applicable as a building block to enable technology for optimal long-term outcomes for pediatric Fontan patients and can also be used to other pediatric and adult cardiac surgeries.

Turner syndrome (TS) is associated with aortic coarctation, dissection and dilation/aneurysm. Predictors of dissection are not well delineated, making decisions regarding prophylactic root replacement challenging. In other disorders, arterial tortuosity is an imaging biomarker associated with increased risk for aortic dissection and adverse cardiovascular events. We aimed to determine if, in TS, arterial tortuosity was associated with aortic dilation or aortic events. We performed a retrospective cohort analysis of unselected women and children with TS who underwent cardiovascular magnetic resonance angiography (MRA) for a prior prospective study. We calculated tortuosity indices including vertebral artery tortuosity index, aortic arch tortuosity index, thoracic aortic tortuosity index (ATI-D), and aortic tortuosity index to the celiac artery (ATI-C). We compared tortuosity in TS patients against age and gender matched controls. We evaluated univariable and multivariable associations between the tortuosity indices and aortic root and ascending aorta size as defined by z-scores, which give a sense of how far a measurement deviates from the mean. We also studied associations between tortuosity and need for aortic root replacement or aortic dissection. Of 184 subjects, with median age 34 years, mean general aortic root z-score was 0.1 ± 1.2 and mean general ascending aortic z-score was 0.4 ± 1.5. Three patients had aortic dissection, and one had prophylactic root replacement, which all occurred prior to first MRA. Vertebral tortuosity index, ATI-D, and ATI-C all increased with age (p 0.0001) for all. ATI-C was associated with larger general ascending z-score. In multivariable analysis, ATI-C remained independently associated with larger ascending aortic z-scores. The relationship between aortic indices and surgery/dissection could not be evaluated since all were collected post-surgery/dissection. Thoracic aortic tortuosity as measured by ATI-C is independently associated with larger ascending aortic dimensions. In this population with only three aortic dissections occurring prior to imaging assessment, we could not assess for associations between aortic tortuosity and dissection. Studies including more patients with aortic dissection are needed to draw further conclusions.

BackgroundPost-operative outcomes of the Fontan operation have been linked to graft shape after implantation. Computational fluid dynamics (CFD) simulations are used to explore different surgical options. The objective of this study is to perform a systematic in vitro validation for investigating the accuracy and efficiency of CFD simulation to predict Fontan hemodynamics.MethodsCFD simulations were performed to measure indexed power loss (iPL) and hepatic flow distribution (HFD) in 10 patient-specific Fontan models, with varying mesh and numerical solvers. The results were compared with a novel in vitro flow loop setup with 3D printed Fontan models. A high-resolution differential pressure sensor was used to measure the pressure drop for validating iPL predictions. Microparticles with particle filtering system were used to measure HFD. The computational time was measured for a representative Fontan model with different mesh sizes and numerical solvers.ResultsWhen compared to in vitro setup, variations in CFD mesh sizes had significant effect on HFD (p = 0.0002) but no significant impact on iPL (p = 0.069). Numerical solvers had no significant impact in both iPL (p = 0.50) and HFD (P = 0.55). A transient solver with 0.5 mm mesh size requires computational time 100 times more than a steady solver with 2.5 mm mesh size to generate similar results.ConclusionsThe predictive value of CFD for Fontan planning can be validated against an in vitro flow loop. The prediction accuracy can be affected by the mesh size, model shape complexity and flow competition.

This paper proposes a semi-automatic Fontan surgery planning method for designing and manufacturing hemodynamically optimized patient-specific grafts. Fontan surgery is a palliative procedure for patients with a single ventricle heart defect by creating a new path using a vascular graft for the deoxygenated blood to be directed to the lungs, bypassing the heart. However, designing patient-specific grafts with optimized hemodynamic performance is a complex task due to the variety of patient-specific anatomies, confined surgical planning space, and the requirement of simultaneously considering multiple design criteria for vascular graft optimization. To address these challenges, we used parameterized Fontan pathways to explore patient-specific vascular graft design spaces and search for optimal solutions by formulating a nonlinear constrained optimization problem, which minimizes indexed power loss (iPL) of the Fontan model by constraining hepatic flow distribution (HFD), percentage of abnormal wall shear stress (%WSS) and geometric interference between Fontan pathways and the heart models (InDep) within clinically acceptable thresholds. Gaussian process regression was employed to build surrogate models of the hemodynamic parameters as well as InDep and [Formula: see text] (conduit model smoothness indicator) for optimization by pattern search. We tested the proposed method on two patient-specific models (n=2). The results showed the automatically optimized (AutoOpt) Fontan models hemodynamically outperformed or at least are comparable to manually optimized Fontan models with significantly reduced surgical planning time (15 hours versus over 2 weeks). We also demonstrated feasibility of manufacturing the AutoOpt Fontan conduits by using electrospun nanofibers.

OBJECTIVE: The current total cavopulmonary connection Fontan has competing inflows and outflows, creating hemodynamic inefficiencies that contribute to Fontan failure and complicate placement and efficiency of mechanical circulatory support. We propose a novel convergent cavopulmonary connection (CCPC) Fontan design to create a single, converged venous outflow to the pulmonary arteries, thus increasing efficiency and mechanical circulatory support access. We then evaluate the feasibility and hemodynamic performance of the CCPC in various patient sizes using computational fluid dynamic assessments of computer-aided designs. METHODS: Cardiac magnetic resonance imaging data from 12 patients with single ventricle (10 total cavopulmonary connection, 2 Glenn) physiology (body surface area, 0.5-2.0 m(2)) were segmented to create 3-dimensional replicas of all thoracic structures. Surgically feasible CCPC shapes within constraints of anatomy were created using iterative computational fluid dynamic and clinician input. Designs varied based on superior and inferior vena cava conduit sizes, coronal attachment height, coronal entry angle, and axial entry angle of the superior vena cava to the inferior vena cava. CCPC designs were optimized based on efficiency (indexed power loss), risk of arteriovenous malformations (hepatic flow distribution), and risk of flow stasis (% nonphysiologic wall shear stress). RESULTS: All CCPC designs met hemodynamic performance thresholds for indexed power loss and hepatic flow distribution. CCPC designs showed improvements in reducing % nonphysiologic wall shear stress and balancing HFD. CONCLUSIONS: CCPC is physiologically and surgically feasible in various patient sizes using validated computational fluid dynamic models. CCPC configuration has analogous indexed power loss, hepatic flow distribution, and % nonphysiologic wall shear stress compared with total cavopulmonary connection, and the single inflow and outflow may ease mechanical circulatory support therapies. Further studies are required for design optimization and mechanical circulatory support institution.

There is currently no clear consensus on screening techniques to evaluate the presence or severity of Fontan-associated liver disease (FALD). Cardiac MRI (CMR) is used routinely for post-Fontan surveillance, but CMR-derived measures that relate to the severity of FALD are not yet defined. This was a cross-sectional single-center study of post-Fontan patients who underwent a CMR. CMR exams were re-analyzed by a single pediatric cardiologist. Surrogates of FALD included Gamma-Glutamyl Transferase (GGT), Fibrosis-4 laboratory score (FIB-4), and imaging findings. Findings consistent with cirrhosis on liver ultrasound included increased liver echogenicity and/or nodularity. Statistical analyses were performed to investigate potential relationships between CMR parameters and markers of FALD. Sixty-one patients were included. A larger inferior vena cava cross-sectional area (IVC-CSA) indexed to height was significantly associated with a higher FIB-4 score (Spearman's ρ = 0.28, p = 0.04), a higher GGT level (Spearman's ρ = 0.40, p = 0.02), and findings consistent with cirrhosis on liver ultrasound (OR 1.17, 95% CI: (1.01, 1.35), p = 0.04). None of the other CMR parameters were associated with markers of FALD. A larger indexed IVC-CSA was associated with higher systemic ventricle end-diastolic pressure (EDP) on cardiac catheterization (Spearman's ρ = 0.39, p = 0.018) as well as older age (Spearman's ρ = 0.46, p = 0.001). Indexed IVC-CSA was the only CMR parameter that was associated with markers of FALD. This measure has the potential to serve as an additional non-invasive tool to improve screening strategies for FALD. Visual abstract summarizing the primary findings of this paper.

Introduction:Adolescents with CHD require transition to specialised adult-centred care. Previous studies have shown that adolescents’ knowledge of their medical condition is correlated with transition readiness. Three-dimensional printed models of CHD have been used to educate medical trainees and patients, although no studies have focused on adolescents with CHD. This study investigates the feasibility of combining patient-specific, digital 3D heart models with tele-education interventions to improve the medical knowledge of adolescents with CHD.Methods:Adolescent patients with CHD, aged between 13 and 18 years old, were enrolled and scheduled for a tele-education session. Patient-specific digital 3D heart models were created using images from clinically indicated cardiac magnetic resonance studies. The tele-education session was performed using commercially available, web-conferencing software (Zoom, Zoom Video Communications Inc.) and a customised software (Cardiac Review 3D, Indicated Inc.) incorporating an interactive display of the digital 3D heart model. Medical knowledge was assessed using pre- and post-session questionnaires that were scored by independent reviewers.Results:Twenty-two adolescents completed the study. The average age of patients was 16 years old (standard deviation 1.5 years) and 56% of patients identified as female. Patients had a variety of cardiac defects, including tetralogy of Fallot, transposition of great arteries, and coarctation of aorta. Post-intervention, adolescents’ medical knowledge of their cardiac defects and cardiac surgeries improved compared to pre-intervention (p < 0.01).Conclusions:Combining patient-specific, digital 3D heart models with tele-education sessions can improve adolescents’ medical knowledge and may assist with transition to adult-centred care.

Background Adults with repaired tetralogy of Fallot (rTOF) are at increased risk for ventricular tachycardia (VT) due to fibrotic remodeling of the myocardium. However, the current clinical guidelines for VT risk stratification and subsequent implantable cardioverter-defibrillator deployment for primary prevention of sudden cardiac death in rTOF remain inadequate. Objective The purpose of this study was to determine the feasibility of using an rTOF-specific virtual-heart approach to identify patients stratified incorrectly as being at low VT risk by current clinical criteria. Methods This multicenter retrospective pilot study included 7 adult rTOF patients who were considered low risk for VT based on clinical criteria. Patient-specific computational heart models were generated from late gadolinium enhanced magnetic resonance imaging (LGE-MRI), incorporating the individual distribution of rTOF fibrotic remodeling in both ventricles. Simulations of rapid pacing determined VT inducibility. Model creation and simulations were performed by operators blinded to clinical outcome. Results Two patients in the study experienced clinical VT. The virtual hearts constructed from LGE-MRI scans of 7 rTOF patients correctly predicted reentrant VT in the models from VT-positive patients and no arrhythmia in those from VT-negative patients. There were no statistically significant differences in clinical criteria commonly used to assess VT risk, including QRS duration and age, between patients who did and those who did not experience clinical VT. Conclusion This study demonstrates the feasibility of image-based virtual-heart modeling in patients with congenital heart disease and structurally abnormal hearts. It highlights the potential of the methodology to improve VT risk stratification in patients with rTOF.

IntroductionA novel handheld dual-electrode stick is a portable atrial fibrillation (AF) screening device (AFSD). We evaluated AFSD performance in primary care patients referred for echocardiogram (echo).MethodsThe AFSD has a light indication of irregular rhythm and single-lead ECG recording. Patients were instructed to hold the device for 1 min, and AF indication was recorded. A 12-lead ECG was performed for all AFSD-positive patients and 250 patients with negative AFSD screen. Echos were performed based on a clinical risk score: all high-risk patients and a sampling of low-risk patients underwent complete echo. Intermediate risk patients first had a screening echocardiogram, with a follow-up complete study if abnormality was suspected.ResultsIn 5 days, 1518 patients underwent clinical evaluation and cardiovascular risk stratification: mean age 58±16 years, 66% women. The AFSD was positive in 6.4%: 12.6% high risk, 6.1% intermediate risk and 2.2% low risk. Older age was a risk factor (9.3% vs 4.8% in those more than and less than 65 years, p=0.001). AFSD positive was independently associated with heart disease in echo (OR=3.9, 95% CI 2.1 to 7.2, pConclusionAFSD demonstrated high sensitivity for AF detection in primary care patients referred for echo. AF prevalence was substantial and independently associated with structural or functional heart disease, suggesting that AFSD screening could be a useful primary care tool to stratify risk and prioritise echo.

Background Patients with single ventricle heart defects receive 3 stages of operations culminating in the Fontan procedure. During the Fontan procedure, a vascular graft is sutured between the inferior vena cava and pulmonary artery to divert deoxygenated blood flow to the lungs via passive flow. Customizing the graft configuration can maximize the long-term benefits. However, planning patient-specific procedures has several challenges, including the ability for physicians to customize grafts and evaluate their hemodynamic performance. Objective The aim of this study was to develop a virtual reality (VR) Fontan graft modeling and evaluation software for physicians. A user study was performed to achieve 2 additional goals: (1) to evaluate the software when used by medical doctors and engineers, and (2) to explore the impact of viewing hemodynamic simulation results in numerical and graphical formats. Methods A total of 5 medical professionals including 4 physicians (1 fourth-year resident, 1 third-year cardiac fellow, 1 pediatric intensivist, and 1 pediatric cardiac surgeon) and 1 biomedical engineer voluntarily participated in the study. The study was pre-scripted to minimize the variability of the interactions between the experimenter and the participants. All participants were trained to use the VR gear and our software, CorFix. Each participant designed 1 bifurcated and 1 tube-shaped Fontan graft for a single patient. A hemodynamic performance evaluation was then completed, allowing the participants to further modify their tube-shaped design. The design time and hemodynamic performance for each graft design were recorded. At the end of the study, all participants were provided surveys to evaluate the usability and learnability of the software and rate the intensity of VR sickness. Results The average times for creating 1 bifurcated and 1 tube-shaped graft after a single 10-minute training session were 13.40 and 5.49 minutes, respectively, with 3 out 5 bifurcated and 1 out of 5 tube-shaped graft designs being in the benchmark range of hepatic flow distribution. Reviewing hemodynamic performance results and modifying the tube-shaped design took an average time of 2.92 minutes. Participants who modified their tube-shaped graft designs were able to improve the nonphysiologic wall shear stress (WSS) percentage by 7.02%. All tube-shaped graft designs improved the WSS percentage compared to the native surgical case of the patient. None of the designs met the benchmark indexed power loss. Conclusions VR graft design software can quickly be taught to physicians with no engineering background or VR experience. Improving the CorFix system could improve performance of the users in customizing and optimizing grafts for patients. With graphical visualization, physicians were able to improve WSS percentage of a tube-shaped graft, lowering the chance of thrombosis. Bifurcated graft designs showed potential strength in better flow split to the lungs, reducing the risk for pulmonary arteriovenous malformations.

BACKGROUND Patients with single ventricle heart defects receive 3 stages of operations culminating in the Fontan procedure. During the Fontan procedure, a vascular graft is sutured between the inferior vena cava and pulmonary artery to divert deoxygenated blood flow to the lungs via passive flow. Customizing the graft configuration can maximize the long-term benefits. However, planning patient-specific procedures has several challenges, including the ability for physicians to customize grafts and evaluate their hemodynamic performance. OBJECTIVE The aim of this study was to develop a virtual reality (VR) Fontan graft modeling and evaluation software for physicians. A user study was performed to achieve 2 additional goals: (1) to evaluate the software when used by medical doctors and engineers, and (2) to explore the impact of viewing hemodynamic simulation results in numerical and graphical formats. METHODS A total of 5 medical professionals including 4 physicians (1 fourth-year resident, 1 third-year cardiac fellow, 1 pediatric intensivist, and 1 pediatric cardiac surgeon) and 1 biomedical engineer voluntarily participated in the study. The study was pre-scripted to minimize the variability of the interactions between the experimenter and the participants. All participants were trained to use the VR gear and our software, CorFix. Each participant designed 1 bifurcated and 1 tube-shaped Fontan graft for a single patient. A hemodynamic performance evaluation was then completed, allowing the participants to further modify their tube-shaped design. The design time and hemodynamic performance for each graft design were recorded. At the end of the study, all participants were provided surveys to evaluate the usability and learnability of the software and rate the intensity of VR sickness. RESULTS The average times for creating 1 bifurcated and 1 tube-shaped graft after a single 10-minute training session were 13.40 and 5.49 minutes, respectively, with 3 out 5 bifurcated and 1 out of 5 tube-shaped graft designs being in the benchmark range of hepatic flow distribution. Reviewing hemodynamic performance results and modifying the tube-shaped design took an average time of 2.92 minutes. Participants who modified their tube-shaped graft designs were able to improve the nonphysiologic wall shear stress (WSS) percentage by 7.02%. All tube-shaped graft designs improved the WSS percentage compared to the native surgical case of the patient. None of the designs met the benchmark indexed power loss. CONCLUSIONS VR graft design software can quickly be taught to physicians with no engineering background or VR experience. Improving the CorFix system could improve performance of the users in customizing and optimizing grafts for patients. With graphical visualization, physicians were able to improve WSS percentage of a tube-shaped graft, lowering the chance of thrombosis. Bifurcated graft designs showed potential strength in better flow split to the lungs, reducing the risk for pulmonary arteriovenous malformations.

Introduction: Graft rejection is a significant contributor to morbidity and mortality in pediatric heart transplant recipients, despite surveillance by endomyocardial biopsy (EMB). Cardiac Magnetic Resonance (CMR) T1 mapping has shown potential for noninvasive diagnosis of rejection. However, variability in normative T1 values across field strengths, vendors, and individual scanners limits the utility of absolute T1 values to diagnose rejection across institutions. Texture analysis is an emerging method for quantifying spatial distribution of relative voxel intensities rather than using the absolute voxel intensities themselves and may serve as an additional method for evaluating T1 maps. Hypothesis: We hypothesized that T1 maps from patients with rejection would exhibit differences in texture features from patients without rejection. Methods: This study included 19 cases from 17 pediatric transplant patients (mean age 11.8 ± 5 year, graft age 5.9 ± 4.7 years, 41% female) who underwent CMR imaging and EMB. 8 short axis slices of breath-held T1 mapping using Modified Look-Locker Inversion (MOLLI) recovery on 1.5T Siemens scanner were obtained. Left ventricular myocardium was semiautomatically segmented from T1 maps, excluding the blood pool and epicardial myocardium. Image texture analysis was performed on a single mid-ventricular slice from each case. Rejection was defined as acute cellular rejection (biopsy grade 1R or higher) or negative biopsy with decreased function requiring treatment. T-test analysis was performed to compare differences in texture analysis between patients with and without rejection. Results: Analysis of T1 maps showed differences (p-value ≤ 0.10) between patients with and without rejection in texture features of energy (0.062 ± 0.012 vs 0.091 ± 0.051), entropy (4.59 ± 0.23 vs 4.23 ± 0.60), and variance (0.031 ± 0.005 vs 0.025 ± 0.009). Discussion: In this small pilot study, texture analysis identified differences in tissue character between patients with and without graft rejection. Evaluation of tissue character via texture analysis may provide an additional method for diagnosis of rejection, given the variability in normative T1 values across institutions.

Introduction: The use of z scores to describe growth of normal structures is necessary in the management of pediatric cardiac disorders, particularly in babies and toddlers. Z score calculators for cardiac magnetic resonance (CMR) have traditionally relied on a convenience sample given complexity of the test. A recently published, novel z score calculator from prospectively-imaged, awake, healthy children ages 0-12 years may add value to assessments of ventricular size compared to traditional calculators. Hypothesis: A novel z score calculator (“Olivieri et al”) with robust prediction in younger, smaller children may reclassify right and left ventricular end diastolic volumes and mass (RVEDV, LVEDV, LVM) compared to the traditional calculator (“Buechel et al”). Methods: A retrospective cohort of subjects less than 12 years of age who underwent clinical CMR imaging on a 1.5T scanner (n=96; median age 5.5 years (IQR 3.7-7.6 years); 42% female) was studied. Z scores were calculated using both novel and traditional models for RVEDV, LVEDV and LVM. Subjects were categorized into the agreement group (both calculators agree) or disagreement groups, where novel calculator reclassified to normal (z< ± 2) or abnormal (z> ±2). Reclassified subject characteristics were compared with ANOVA and t-test. Results: Novel and traditional z scores agreed for 77%, 58% and 62% of cases for RVEDV, LVEDV and LVM, respectively. Amongst disagreements, subjects reclassified from abnormal to normal by the novel calculator had significantly lower age, BSA and RV size (Table 1). Reclassified subjects showed no association with specific diagnoses. Conclusion: The novel z score calculator reclassifies younger, smaller children away from severe z scores into more normal z scores. Ventricular volume assessment is highly relevant to critical decision-making in the first years of life in borderline lesions.

Introduction: Cardiac magnetic resonance (CMR) now allows for time-resolved three-dimensional phase-contrast (4D flow) analysis of congenital heart disease (CHD). In infants with small vessels, the influence of contrast agent type (ferumoxytol vs. gadolinium) on 4D flow has not been investigated. Thus, we investigated the accuracy of 4D flow measurements in ferumoxytol vs. gadolinium-enhanced CMR of small CHD patients. Methods: This was a retrospective study consisting of CMR studies from CHD patients less than 20 kg who had ferumoxytol or gadolinium-enhanced 4D flow and standard phase contrast (2D-PC) flow collected. 4D flow clinical software (Arterys) was used to measure flow in great vessels, systemic veins and pulmonary veins. 4D flow accuracy was defined as % difference or correlation against conventional measurements from (2D-PC) of the same vessels. Subgroup analysis was performed on two-ventricular (2V) vs. single ventricular (1V) CHD, as well as low flows (defined as < 1.5 L/min) in 1V CHD. Results: Twenty-one ferumoxytol-enhanced and 23 gadolinium-enhanced CMR studies were included, with no difference in age (2.1 ± 1.5 vs. 2.3 ± 1.8 years, p = 0.7), patient size (0.49 ± 0.18 vs. 0.51 ± 0.16 m 2 , p = 0.67), or vessel diameter (11.4 ± 5.2 vs. 12.4 ± 5.6, p = 0.22). 10 CMR studies with 1V CHD were included. Overall, ferumoxytol-enhanced 4D flow measurements demonstrated less % difference to 2D-PC when compared to gadolinium-enhanced studies (Figure 1A). In subgroup analysis of low flows in 1V CHD, ferumoxytol-enhanced 4D flow measurements had stronger correlation to 2D-PC (Figure 1B). Conclusions: In infants, ferumoxytol-enhanced 4D flow has improved accuracy when compared to gadolinium, particularly for small vessels in 1V CHD.

Introduction: Cardiac Magnetic Resonance (CMR) is an emerging tool for cardiac graft assessment in heart transplant recipients, with native T1 mapping directed at identifying both rejection and graft fibrosis to predict and guide management of graft dysfunction. Hypothesis: CMR native T1 values may identify acute rejection, predict graft dysfunction, and in secondary analysis, correlate with fibrosis percentage from right ventricle (RV) endomyocardial biopsy (EMB). Methods: Pediatric subjects (n=34, age 12.4±4.9 y, graft age 5.4±4.3 y, LVEF 62.9±5.6%) underwent simultaneous EMB and 1.5T CMR with breath-held T1 mapping via Modified Look-Locker Inversion recovery in 8 short-axis slices, from which global mean and peak native T1 values were quantified. EMB analyzed for histopathological fibrosis% using digital analysis of Maisson’s trichrome stained slides. Patients were stratified into three groups by decision to treat: acute rejection with new treatment initiated, ongoing treatment modified, or no change in treatment. In patients without acute rejection, linear regression was used to compare T1 values with clinical markers of right atrial (RA) mean pressure and brain natriuretic peptide (BNP). Results: Mean T1 values were higher in patients with acute rejection compared to those without, with stratified groups demonstrating a monotonic trend; peak T1 values trended towards significance. In patients without acute rejection, peak T1 values correlated with BNP (r=0.53, p=0.004) and RA mean pressure (r=0.39, p=0.046). Fibrosis% from random RV EMB did not correlate with native T1 values or clinical markers of graft dysfunction. Conclusion: In pediatric heart transplant patients, T1 values from comprehensive CMR identified acute rejection requiring initiation of treatment and graft dysfunction, with regional analysis key to capturing correlation with clinical markers. CMR shows promise as an important tool for evaluation of graft health in children.

An 8-year-old with a known diagnosis of an asymptomatic coronary artery fistula (CAF) presented with exertional syncope and haemopericardium due to contained rupture of CAF. A transcatheter closure was attempted, but the fistula ruptured again prompting emergency surgical repair. Spontaneous rupture is a catastrophic complication of CAF and warrants a high index of suspicion, timely diagnosis and team management.

Background The interventional cardiac magnetic resonance imaging suite combines a cardiac catheterization x-ray laboratory with a magnetic resonance imaging suite. At the study institution, interventional cardiac magnetic resonance imaging procedures (ie, magnetic resonance imaging–guided cardiac catheterizations) have been performed under institutional review board–approved research protocols since 2015. Because the workplace incorporates x-ray and magnetic resonance imaging in a highly technical environment, education about the importance of magnet safety is crucial to ensure the safety of patients and staff. Objective To promote magnetic resonance imaging safety and staff preparedness to respond in emergency situations in a specialized interventional cardiac magnetic resonance imaging environment. Methods Quarterly in situ evacuation drills with a live volunteer were implemented. A retrospective participant survey using a Likert scale was conducted. Evacuations were timed from the cardiac arrest code alert to safe evacuation or defibrillation if appropriate. Results Over 4 years, 14 drills were performed. Twenty-nine of 48 participants responded to the survey, a 60% response rate. Most participants agreed or strongly agreed that the drills were a positive experience (90%) and that the drills increased their confidence in their ability to perform in an evacuation scenario (100%). Room evacuation times improved from 71 to 41 seconds. No patient or staff safety events occurred in the interventional cardiac magnetic resonance imaging environment. Conclusion Magnetic resonance imaging–guided cardiac catheterization evacuation drills promote preparedness, ensure patient and staff safety, and improve evacuation time in the interventional cardiac magnetic resonance imaging environment.

Background The global effect of chronic pulmonary regurgitation (PR) on right ventricular (RV) dilation and dysfunction in repaired Tetralogy of Fallot (rTOF) patients is well studied by cardiovascular magnetic resonance (CMR). However, the links between PR in the RV outflow tract (RVOT), RV dysfunction and exercise intolerance are not clarified by conventional measurements. Not all patients with RV dilation share the same intracardiac flow characteristics, now measurable by time resolved three-dimensional phase contrast imaging (4D flow). In our study, we quantified regional vorticity and energy loss in rTOF patients and correlated these parameters with RV dysfunction and exercise capacity. Methods rTOF patients with 4D flow datasets were retrospectively analyzed, including those with transannular/infundibular repair and conduit repair. Normal controls and RV dilation patients with atrial-level shunts (Qp:Qs > 1.2:1) were included for comparison. 4D flow was post-processed using IT Flow (Cardioflow, Japan). Systolic/diastolic vorticity (ω, 1/s) and viscous energy loss (VEL, mW) in the RVOT and RV inflow were measured. To characterize the relative influence of diastolic vorticity in the two regions, an RV Diastolic Vorticity Quotient (ωRVOT-Diastole/ωRV Inflow-Diastole, RV-DVQ) was calculated. Additionally, RVOT Vorticity Quotient (ωRVOT-Diastole/ωRVOT-Systole, RVOT-VQ) and RVOT Energy Quotient (VELRVOT-Diastole/VELRVOT-Systole, RVOT-EQ) was calculated. In rTOF, measurements were correlated against conventional CMR and exercise stress test results. Results 58 rTOF patients, 28 RV dilation patients and 12 controls were included. RV-DVQ, RVOT-VQ, and RVOT-EQ were highest in rTOF patients with severe PR compared to rTOF patients with non-severe PR, RV dilation and controls (p 2-max (− 0.587, p = 0.008 and − 0.617, p = 0.005) and % predicted VO2-max (− 0.678, p = 0.016 and − 0.690, p = 0.001). Conclusions In rTOF patients, vorticity and energy loss dominate the RVOT compared to tricuspid inflow, correlating with RV dysfunction and exercise intolerance. These 4D flow-based measurements may be sensitive biomarkers to guide surgical management of rTOF patients.