Hypoplastic Left Heart Syndrome with Mitral Stenosis and Aortic Atresia-Echocardiographic Findings and Early Outcomes.

BACKGROUND: Mitral stenosis/aortic atresia (MS/AA) has been reported as a high-risk variant of hypoplastic left heart syndrome (HLHS), potentially related to ventriculocoronary connections (VCCs) or endocardial fibroelastosis (EFE) and myocardial hypoperfusion. We aimed to identify echocardiographic and clinical factors associated with early death or transplant in this group. METHODS: Patients with HLHS MS/AA treated at our center between 2000 and 2020 were included. Pre-stage I palliation echocardiograms were reviewed. Certain imaging factors, such as determination of VCC, EFE, and measurement of tricuspid annular plane systolic excursion were measured from retrospective review of preoperative images; others were derived from clinical reports. Groups were compared according to primary outcome of death or transplant prior to stage II palliation. RESULTS: Of 141 patients included, 39 (27.7%) experienced a primary outcome. Ventriculocoronary connections were identified in 103 (73.0%) patients and EFE in 95 (67.4%) patients. Among imaging variables, smaller ascending aorta size (median, 2.2 [interquartile range (IQR) 1.7-2.8] vs 2.6 [2.2-3.4] mm, P = .01) was associated with primary outcome. There was similar frequency of VCC (74.4% vs 72.5%, P = .83), EFE (59.0% vs 72.5%, P = .19), moderate or greater tricuspid regurgitation (5.1% vs 5.9%, P = 1.00), and similar right ventricular systolic function (indexed tricuspid annular plane systolic excursion 32.5 ± 7.3 vs 31.4 ± 7.2 mm/m2, P = .47) in the primary outcome group compared to other patients. Clinical factors associated with primary outcome included lower birth weight (mean, 2.8 ± SD 0.8 vs 3.3 ± 0.5 kg, P = .0003), gestational age <37 weeks (31.6% vs 4.9%, P < .0001), longer cardiopulmonary bypass time (median, 112 [IQR, 93-162] vs 82 [71-119] minutes, P = .001), longer intensive care unit length of stay (median, 19 [IQR, 10-30] vs 10 [7-15] days, P = .001), and extracorporeal membrane oxygenation following stage I palliation (43.6% vs 8.8%, P < .0001). Presence of VCCs and EFE was not associated with death or transplant after controlling for birth weight and era of stage I palliation. CONCLUSIONS: In one of the largest reported single-center cohorts of HLHS MS/AA, there were few pre-stage I palliation imaging characteristics associated with primary outcome. Imaging findings evaluated in this study, including the presence of VCC and/or EFE as determined using highly sensitive echocardiogram criteria, should not preclude intervention, although impact on long-term outcomes requires further evaluation.

Real-Time Strain-Encoding Cardiovascular MRI for Assessment of Regional Heart Function in Tetralogy of Fallot Patients.

BACKGROUND: Tetralogy of Fallot (ToF) is the most common form of cyanotic congenital heart disease, where right ventricular (RV) function is an important determinant of subsequent intervention. OBJECTIVE: In this study, we evaluate the feasibility of fast strain-encoding (fastSENC; a one-heartbeat sequence) magnetic resonance imaging (MRI) for assessing regional cardiac function in ToF. METHOD: FastSENC was implemented to characterize regional circumferential (Ecc) and longitudinal (Ell) strains in the left ventricle (LV) and RV in post-repair ToF. Data analysis was conducted to compare strain measurements in the RV to those in the LV, as well as to those generated by the MRI Tissue-Tracking (MRI-TT) technique, and to assess the relationship between strain and ejection fraction (EF). RESULTS: Despite normal LVEF (55±8.5%), RVEF was borderline (46±6.4%), but significantly lower than LVEF. RV strains (RV-Ell=-20.2±2.9%, RV-Ecc=-15.7±6.4%) were less than LV strains (LV-Ell=-21.7±3.7%, LV-Ecc=-18.3±4.7%), and Ell was the dominant strain component. Strain differences between fastSENC and MRI-TT were less significant in RV than in LV. There existed moderate and weak correlations for RV-Ecc and RV-Ell, respectively, against RVEF. Compared to LV strain, RV strain showed regional heterogeneity with a trend for reduced strain from the inferior to anterior regions. Inter-ventricular strain delay was larger for Ell (64±47ms) compared to Ecc (36±40ms), reflecting a trend for contraction dyssynchrony. CONCLUSION: FastSENC allows for characterizing subclinical regional RV dysfunction in ToF. Due to its sensitivity for evaluating regional myocardial contractility patterns and real-time imaging capability without the need for breath-holding, fastSENC makes it more suitable for evaluating RV function in ToF.

Effects of Mitral Valve Prolapse on Quantification of Mitral Regurgitation and Ejection Fraction Using Cardiac MRI.

Purpose: To determine the impact of prolapsed volume on regurgitant volume (RegV), regurgitant fraction (RF), and left ventricular ejection fraction (LVEF) in patients with mitral valve prolapse (MVP) using cardiac MRI. Materials and Methods: Patients with MVP and mitral regurgitation who underwent cardiac MRI from 2005 to 2020 were identified retrospectively from the electronic record. RegV is the difference between left ventricular stroke volume (LVSV) and aortic flow. Left ventricular end-systolic volume (LVESV) and LVSV were obtained from volumetric cine images, with prolapsed volume inclusion (LVESVp, LVSVp) and exclusion (LVESVa, LVSVa) providing two estimates of RegV (RegVp, RegVa), RF (RFp, RFa), and LVEF (LVEFa, LVEFp). Interobserver agreement for LVESVp was assessed using intraclass correlation coefficient (ICC). RegV was also calculated independently using measurements from mitral inflow and aortic net flow phase-contrast imaging as the reference standard (RegVg). Results: The study included 19 patients (mean age, 28 years ± 16 [SD]; 10 male patients). Interobserver agreement for LVESVp was high (ICC, 0.98; 95% CI: 0.96, 0.99). Prolapsed volume inclusion resulted in higher LVESV (LVESVp: 95.4 mL ± 34.7 vs LVESVa: 82.4 mL ± 33.8; P < .001), lower LVSV (LVSVp: 100.5 mL ± 33.8 vs LVSVa: 113.5 mL ± 35.9; P < .001), and lower LVEF (LVEFp: 51.7% ± 5.7 vs LVEFa: 58.6% ± 6.3; P < .001). RegV was larger in magnitude when prolapsed volume was excluded (RegVa: 39.4 mL ± 21.0 vs RegVg: 25.8 mL ± 22.8; P = .02), with no evidence of a difference when including prolapsed volume (RegVp: 26.4 mL ± 16.4 vs RegVg: 25.8 mL ± 22.8; P > .99). Conclusion: Measurements that included prolapsed volume most closely reflected mitral regurgitation severity, but inclusion of this volume resulted in a lower LVEF.Keywords: Cardiac, MRI© RSNA, 2023See also commentary by Lee and Markl in this issue.

Recommendations for Cardiac Point-of-Care Ultrasound in Children: A Report from the American Society of Echocardiography.

Cardiac point-of-care ultrasound has the potential to improve patient care, but its application to children requires consideration of anatomic and physiologic differences from adult populations, and corresponding technical aspects of performance. This document is the product of an American Society of Echocardiography task force composed of representatives from pediatric cardiology, pediatric critical care medicine, pediatric emergency medicine, pediatric anesthesiology, and others, assembled to provide expert guidance. This diverse group aimed to identify common considerations across disciplines to guide evolution of indications, and to identify common requirements and infrastructure necessary for optimal performance, training, and quality assurance in the practice of cardiac point-of-care ultrasound in children. The recommendations presented are intended to facilitate collaboration among subspecialties and with pediatric echocardiography laboratories by identifying key considerations regarding (1) indications, (2) imaging recommendations, (3) training and competency assessment, and (4) quality assurance.

Data-driven computational models of ventricular-arterial hemodynamics in pediatric pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a complex disease involving increased resistance in the pulmonary arteries and subsequent right ventricular (RV) remodeling. Ventricular-arterial interactions are fundamental to PAH pathophysiology but are rarely captured in computational models. It is important to identify metrics that capture and quantify these interactions to inform our understanding of this disease as well as potentially facilitate patient stratification. Towards this end, we developed and calibrated two multi-scale high-resolution closed-loop computational models using open-source software: a high-resolution arterial model implemented using CRIMSON, and a high-resolution ventricular model implemented using FEniCS. Models were constructed with clinical data including non-invasive imaging and invasive hemodynamic measurements from a cohort of pediatric PAH patients. A contribution of this work is the discussion of inconsistencies in anatomical and hemodynamic data routinely acquired in PAH patients. We proposed and implemented strategies to mitigate these inconsistencies, and subsequently use this data to inform and calibrate computational models of the ventricles and large arteries. Computational models based on adjusted clinical data were calibrated until the simulated results for the high-resolution arterial models matched within 10% of adjusted data consisting of pressure and flow, whereas the high-resolution ventricular models were calibrated until simulation results matched adjusted data of volume and pressure waveforms within 10%. A statistical analysis was performed to correlate numerous data-derived and model-derived metrics with clinically assessed disease severity. Several model-derived metrics were strongly correlated with clinically assessed disease severity, suggesting that computational models may aid in assessing PAH severity.

Cardiac Magnetic Resonance to Predict Coronary Artery Compression in Transcatheter Pulmonary Valve Implantation Into Conduits.

OBJECTIVES: The aim of this study was to evaluate the accuracy of cardiac magnetic resonance (CMR) in predicting coronary artery (CA) compression during transcatheter pulmonary valve implantation (TPVi). BACKGROUND: TPVi is a widely available option to treat dysfunctional right ventricle (RV)-to-pulmonary artery (PA) conduits, but CA compression is an absolute contraindication. CMR can evaluate coronary anatomy, but its utility in predicting CA compression is not well established. METHODS: After Institutional Review Board approval was obtained, all patients at 9 centers with attempted TPVi in RV-PA conduits and recent CMR (≤12 months) were analyzed. A core laboratory reviewed all CMR studies for the shortest orthogonal distance from a CA to the conduit, the shortest distance from a CA to the most stenotic area of the conduit, and subjective assessment of CA compression risk. RESULTS: Among 231 patients, TPVi was successful in 198 (86%); in 24 (10%), balloon testing precluded implantation (documented CA compression or high risk). Distance to the RV-PA conduit ≤2.1 mm (area under the curve [AUC]: 0.70) and distance to most stenotic area ≤13.1 mm (AUC: 0.69) predicted CA compression. Subjective assessment had the highest AUC (0.78), with 96% negative predictive value. Both distances and qualitative assessment remained independently associated with CA compression when controlling for abnormal coronary anatomy or degree of conduit calcification. CONCLUSIONS: CMR can help predict the risk for CA compression during TPVi in RV-PA conduits but cannot completely exclude CA compression. CMR may assist in patient selection and counseling families prior to TPVi, although balloon testing remains essential.

Kommerell Diverticulum: Distinctions Between Arch Side and Evaluation of Morphology, Size, And Risk.

BACKGROUND: Kommerell diverticulum (KD) is a dilated proximal aberrant right or left subclavian artery associated with either right or left aortic arches (RAA-ARSA or LAA-ALSA). Although case series suggest that KD may be a liability for vascular complications, the risk, pattern of dilation throughout the life span, and differences between arch sides are not known. METHODS: This study was a single-center retrospective review of patients of all ages with KD on cross-sectional imaging. Maximal short-axis diameter of KD (KDmax), absolute and indexed to descending aortic diameter (DAo), was correlated with age. Comparisons were made between arch sides. Patients with vascular complications were described. RESULTS: A total of 104 patients with KD were included: 68 (65%) with RAA-ALSA, 36 (35%) with LAA-ARSA, 43 (41%) asymptomatic. Although KDmax was correlated with age (RAA-ALSA r = 0.84; [P< .0001]; LAA-ARSA r = 0.51 [P = .001]), KDmax indexed to DAo was not (RAA-ALSA r = 0.14 [P = .27]; LAA-ARSA r = -0.22 [P = .21]). Patients with RAA-ALSA had larger KDmax indexed to DAo (1.02 ± 0.20 mm/mm vs 0.89 ± 0.18 mm/mm; P = .002) and more symptoms (75% vs 28%; P < .0001), and they were younger (median, 9.5 years vs 61.7 years; P < .0001). Six patients (58 to 80 years of age) had vascular complications, and all 6 had LAA-ARSA and risk factors for acquired aneurysms. CONCLUSIONS: In older patients, KDmax indexed to DAo was not larger, thus arguing against isolated KD dilation with age. Diverticula from RAA-ALSA and LAA-ARSA demonstrated different phenotypes, a finding suggesting different disease processes and likely different risk. The incidence of vascular complications was lower than in previous reports, and these complications occurred exclusively in patients with LAA-ARSA and aneurysm risk factors. This finding suggests that conservative management of asymptomatic KD is often reasonable, especially in patients with RAA-ALSA.

Ventricular Function in Physiologically Repaired and Unrepaired Congenitally Corrected Transposition of the Great Arteries.

In patients with congenitally corrected transposition of the great arteries (ccTGA) and hemodynamically significant concomitant lesions, physiologic repair may be undertaken, in which the circulation is septated but the morphologic right ventricle (RV) remains the systemic ventricle. Patients without significant concomitant lesions may be observed without surgery, with a similar physiologic result. We compared cardiovascular magnetic resonance measures of ventricular size and function in patients with physiologically repaired and unrepaired ccTGA. Patients with ccTGA who underwent cardiovascular magnetic resonance at our center between September 2007 and July 2019 were analyzed. In 38 patients identified (12, physiologically repaired; 26, unrepaired; mean age 34.5 [18.7 to 52.0] years), there was a higher proportion of RV ejection fraction ≤45% in physiologically repaired (75% vs unrepaired 35%, p = 0.02). Physiologically repaired patients had worse left ventricle global longitudinal strain (-14.9% ± 5.0% vs unrepaired patients -18.4% ± 2.7%, p = 0.04). The difference in tricuspid regurgitant fraction between groups did not achieve statistical significance (physiologically repaired 27.4 ± 11.1% vs unrepaired patients 19.2 ± 13.0%, p = 0.08). Evaluation for late gadolinium enhancement was more commonly undertaken in physiologically repaired patients (8 of 12 vs unrepaired 7 of 26, p = 0.03) and present more frequently in the left ventricle in physiologically repaired patients in patients evaluated (6 of 8 vs unrepaired 0 of 7, p = 0.01). In conclusion, ventricular function is decreased in patients with ccTGA undergoing physiologic repair compared with those without previous surgery. These cohorts should be considered separately when using ventricular function as an outcome. RV dysfunction is concerning for long-term outcomes following physiologic repair.

Interventional Planning for Endovascular Revision of a Lateral Tunnel Fontan: A Patient-Specific Computational Analysis.

INTRODUCTION: A 2-year-old female with hypoplastic left heart syndrome (HLHS)-variant, a complex congenital heart defect (CHD) characterized by the underdevelopment of the left ventricle, presented with complications following single ventricle palliation. Diagnostic work-up revealed elevated Fontan pathway pressures, as well as significant dilation of the inferior Fontan pathway with inefficient swirling flow and hepatic venous reflux. Due to the frail condition of the patient, the clinical team considered an endovascular revision of the Fontan pathway. In this work, we performed a computational fluid dynamics (CFD) analysis informed by data on anatomy, flow, and pressure to investigate the hemodynamic effect of the endovascular Fontan revision. METHODS: A patient-specific anatomical model of the Fontan pathway was constructed from magnetic resonance imaging (MRI) data using the cardiovascular modeling software CardiovasculaR Integrated Modeling and SimulatiON (CRIMSON). We first created and calibrated a pre-intervention 3D-0D multi-scale model of the patient's circulation using fluid-structure interaction (FSI) analyses and custom lumped parameter models (LPMs), including the Fontan pathway, the single ventricle, arterial and venous systemic, and pulmonary circulations. Model parameters were iteratively tuned until simulation results matched clinical data on flow and pressure. Following calibration of the pre-intervention model, a custom bifurcated endograft was introduced into the anatomical model to virtually assess post-intervention hemodynamics. RESULTS: The pre-intervention model successfully reproduced the clinical hemodynamic data on regional flow splits, pressures, and hepatic venous reflux. The proposed endovascular repair model revealed increases of mean and pulse pressure at the inferior vena cava (IVC) of 6 and 29%, respectively. Inflows at the superior vena cava (SVC) and IVC were each reduced by 5%, whereas outflows at the left pulmonary artery (LPA) and right pulmonary artery (RPA) increased by 4%. Hepatic venous reflux increased by 6%. CONCLUSION: Our computational analysis indicated that the proposed endovascular revision would lead to unfavorable hemodynamic conditions. For these reasons, the clinical team decided to forgo the proposed endovascular repair and to reassess the management of this patient. This study confirms the relevance of CFD modeling as a beneficial tool in surgical planning for single ventricle CHD patients.

Improving MR Image Quality in Patients with Metallic Implants.

The number of implanted devices such as orthopedic hardware and cardiac implantable devices continues to increase with an increase in the age of the patient population, as well as an increase in the number of indications for specific devices. Many patients with these devices have or will develop clinical conditions that are best depicted at MRI. However, implanted devices containing paramagnetic or ferromagnetic substances can cause significant artifact, which could limit the diagnostic capability of this modality. Performing imaging with MRI when an implant is present may be challenging, and there are numerous techniques the radiologist and technologist can use to help minimize artifacts related to implants. First, knowledge of the presence of an implant before patient arrival is critical to ensure safety of the patient when the device is subjected to a strong magnetic field. Once safety is ensured, the examination should be performed with the MRI system that is expected to provide the best image quality. The selection of the MRI system includes multiple considerations such as the effects of field strength and availability of specific sequences, which can reduce metal artifact. Appropriate patient positioning, attention to MRI parameters (including bandwidth, voxel size, and echo), and appropriate selection of sequences (those with less metal artifact and advanced metal reduction sequences) are critical to improve image quality. Patients with implants can be successfully imaged with MRI with appropriate planning and understanding of how to minimize artifacts. This improves image quality and the diagnostic confidence of the radiologist. ©RSNA, 2021.

Characterization of Post-Operative Hemodynamics Following the Norwood Procedure Using Population Data and Multi-Scale Modeling.

Children with hypoplastic left heart syndrome (HLHS) must undergo multiple surgical stages to reconstruct the anatomy to a sustainable single ventricle system. Stage I palliation, or the Norwood procedure, provides circulation to both pulmonary and systemic vasculature. The aorta is reconstructed and attached to the right ventricle and a fraction of systemic flow is redirected to the pulmonary arteries (PAs) through a systemic-to-PA shunt. Despite abundant hemodynamic data available 4-5 months after Norwood palliation, data is very scarce immediately following stage I. This data is critical in determining post-operative success. In this work, we combined population data and computational fluid dynamics (CFD) to characterize hemodynamics immediately following stage I (post-stage I) and prior to stage II palliation (pre-stage II). A patient-specific model was constructed as a baseline geometry, which was then scaled to reflect population-based morphological data at both time-points. Population-based hemodynamic data was then used to calibrate each model to reproduce blood flow representative of HLHS patients. The post-stage I simulation produced a PA pressure of 22 mmHg and high-frequency oscillations within the flow field indicating highly disturbed hemodynamics. Despite PA mean pressure dropping to 14 mmHg, the pre-stage II model also produced high-frequency flow components and PA wall shear stress increases. These suboptimal conditions may be necessary to ensure adequate PA flow throughout the pre-stage II period, as the shunt becomes relatively smaller compared to the patient's somatic growth. In the future, CFD can be used to optimize shunt design and minimize these suboptimal conditions.

Improving adherence to echocardiogram reporting guidelines in patients with repaired tetralogy of fallot: A quality improvement initiative.

BACKGROUND: In patients with repaired tetralogy of Fallot (TOF), key echocardiogram report elements have been identified, but poor adherence has been demonstrated, particularly for quantitative assessment. We report a quality improvement effort to improve adherence at our institution, with a focus on increasing quantitative assessment of right ventricular (RV) function. METHODS: Baseline compliance was established by a 3-month retrospective review of outpatient echocardiogram reports. Intervention 1 included presenting baseline data and reviewing the guidelines with echocardiogram laboratory staff (physicians and sonographers). Intervention 2, chosen to focus on quantitative assessment of RV function, involved recommending measurement of tricuspid annular plane systolic excursion (TAPSE) for all echocardiograms. Reporting rates were prospectively analyzed for 1 month after each intervention. To evaluate sonographer versus physician compliance, both study images (acquisition of TAPSE images) and reports were reviewed. RESULTS: At baseline, adherence was poor (median 65% of elements reported), with lower rates for measurements versus descriptive elements (median 40% vs 78%, p<.0001). Following intervention 1, total reported elements improved (median 71% vs 65%, p=0.02) due to increase in measurements (median 50% vs 40%, p=0.02). Reports of quantitative RV function did not significantly change after either intervention, but sonographer compliance improved after intervention 1 (33% vs 14%, p=0.03), with further improvement after intervention 2 (53% vs 14%, p=0.001). CONCLUSION: While education on lesion-specific guidelines may modestly improve adherence, standardization has a greater effect. However, interventions may have differential impact on sonographers versus attendings, and iterative interventions may be required to change practice patterns.

Echocardiographic Findings Associated with Transplantation-Free Survival and Left Ventricular Systolic Function at Midterm Follow-Up after Ross Procedure in Infants with Critical Aortic Stenosis.

BACKGROUND: The Ross operation is an important option for children with critical aortic stenosis with residual disease, but operation in infancy is associated with significant morbidity and mortality. The aim of this study was to evaluate echocardiographic correlates of transplantation-free survival, reintervention, and left ventricular (LV) function in midterm follow-up. METHODS: This retrospective, single-center study included all infants with critical aortic stenosis who underwent Ross by 1 year of age from January 2000 to September 2018. Serial echocardiograms were analyzed for LV ejection fraction (LVEF) and systolic and diastolic longitudinal strain. The primary outcome was mortality or transplantation; secondary outcomes were reintervention and abnormal LVEF (≤55%). RESULTS: Among 40 infants (30 male [75%]; median age at Ross, 51 days) with median follow-up duration of 3.3 years (interquartile range, 1.0-9.4 years), the primary outcome was met in 11 (28%). Rates of transplantation-free survival was 79%, 77%, and 69% at 1, 5, and 10 years after Ross. Predictors of transplantation or death included neonatal surgery, cross-clamp time, and preoperative left atrial dilatation and lower LVEF. Median freedom from reintervention was 7.1 years after Ross, with no identified associations. LV longitudinal strain improved 1 year after Ross (-21.1 ± 3.8% vs -17.4 ± 5.1%, P = .02), although LVEF did not reach significance. Lower LVEF at 1 year was related to pre-Ross left atrial dilatation (P = .02), abnormal LVEF (P = .04), and lower early diastolic longitudinal strain rate (P = .03). LVEF remained stable 3 years after Ross. CONCLUSIONS: Both transplantation-free survival and normalization of LV function after Ross in infancy are associated with preoperative LV systolic and diastolic measures, highlighting the prognostic value of echocardiography in this population. Further data are necessary in a larger, multicenter cohort to allow more precise risk stratification.

Emerging 3D technologies and applications within congenital heart disease: teach, predict, plan and guide.

3D visualization technologies have evolved to become a mainstay in the management of congenital heart disease (CHD) with a growing presence within multiple facets. Printed and virtual 3D models allow for a more comprehensive approach to educating trainees and care team members. Computational fluid dynamics can take 3D modeling to the next level, by predicting post-procedural outcomes and helping to determine surgical approach. 3D printing and extended reality are developing resources for pre-procedural planning and intra-procedural guidance with the potential to revolutionize decision-making and procedural success. Challenges still remain within existing technologies and their applications to the CHD field. Addressing these gaps, both by those within and outside of CHD, will transform education and patient care within our field.

Neo-aortic Root Dilatation, Aortic Stiffness, and Ventricular interactions in Long-Term Follow-Up After the Ross Procedure in Childhood.

Patients after the Ross procedure are at risk for right (RV) and left ventricular (LV) dysfunction due to neo-aortic and pulmonary dysfunction. While neo-aortic root dilatation has been related to LV dysfunction, the potential contributions of aortic stiffness and ventricular interactions have not been evaluated. Patients status post Ross procedure up to age 18 years with cardiac magnetic resonance (CMR) exam from 2007 to 2018 were retrospectively reviewed. Aortic pulse wave velocity (PWV) was calculated from phase contrast and angiogram images. RV and LV peak global longitudinal (GLS) and circumferential strain (GCS) were measured using tissue tracking software. Multivariable regression was performed for variables associated with parameters of LV function. In 58 patients (median age 20.5 years at CMR exam), male gender, longer time since Ross procedure, aortic root dilatation, and lower RV ejection fraction (EF) were associated with decreased LV EF. There was no association with LV late gadolinium enhancement or neo-aortic or conduit regurgitation. LV GCS and GLS also correlated with RV GCS, RV GLS and PWV. In multivariable analysis, the relation of RV and LV systolic function, but not aortic measurements, remained significant. In conclusion, in long-term follow-up after pediatric Ross procedure, RV function rather than aortic root size or aortic stiffness most closely relates to LV function. Ventricular interactions may impact decision-making on timing of conduit intervention, which could differ from established criteria in populations with only aortic or pulmonary valve disease. Further study is warranted to evaluate possible association with clinical outcome.

Differences in Pulmonary and Systemic Flow Measurements by Cardiac Magnetic Resonance vs Cardiac Catheterization and Relation to Collateral Flow in Single Ventricle Patients.

Both cardiac magnetic resonance (CMR) and cardiac catheterization (cath) may assess patients with single ventricle physiology prior to stage II or Fontan palliation. However, development of significant aortopulmonary collaterals may invalidate assumptions of the Fick method. We compared CMR and cath flow measurements and evaluated the relation to collateral flow. This single-center study included all pre-stage II and pre-Fontan patients between 2010 and 2017 with CMR and cath within 1 month. Pulmonary (Qp) and systemic flow (Qs) by cath were calculated by Fick method. CMR Qp was calculated by total pulmonary venous flow, and Qs by total vena caval flow. Collateral flow by CMR was the difference of pulmonary vein and pulmonary artery flow. In 26 studies (16 pre-stage II and 10 pre-Fontan) in 21 patients, collateral flow was higher in pre-Fontan patients (1.8 ± 0.6 vs 0.9 ± 0.8 L/min/m2, p = 0.01). Overall, CMR and cath had good agreement for Qs and Qp:Qs, with moderate correlation (r = 0.44, p = 0.02 for Qs, r = 0.48, p = 0.02 for Qp:Qs). In pre-Fontan but not in pre-stage II patients, CMR had higher Qp (mean difference - 1.71 L/min/m2) and Qp:Qs (mean difference - 0.36). The underestimation of cath Qp correlated with amount of collateral flow (r = - 0.47, p = 0.02). Neither cath nor CMR flow measurements correlated with outcomes in this small cohort. In conclusion, collaterals lead to systematically higher Qp and Qp:Qs measurements by CMR vs cath in single ventricle patients. Measurements may not be used interchangeably, with potential clinical significance in estimating pulmonary vascular resistance. Further study is necessary to evaluate possible relation to clinical outcomes.