Outcomes of the Surgical Management of Atrial Isomerism and Functional Single Ventricle: A Single-Centered Cohort From China

Objectives: The management of atrial isomerism with complex congenital heart disease remains challenging. Experience has been largely obtained in advanced countries. The clinical diversity is greater in China. We evaluated the early- and medium-term outcomes of surgical treatment of these patients.Methods: We reviewed 86 patients of atrial isomerism with complex congenital heart disease undergoing varied surgeries in our center in 2008–2020. Cox regression models were used to analyze the risk factors for mortality.Results: There were 75 cases of right and 11 of left atrial isomerism. Eighty-three (96.5%) patients underwent single-ventricle staged palliation approach, with 10 early and 7 late deaths. The overall 1-, 5-, and 10-year survival rates were 84.7, 79.3, and 79.3%, respectively. Thirty-six (43.4%) patients completed the Fontan procedure with median age of 48 months and freedom from death or Fontan failure at 1-, 5-, and 8-years were 94.4, 87.4, and 80.7%, respectively. Concomitant total anomalous pulmonary venous connection [hazard ratio (HR): 5.15 (1.95–12.94), p = 0.008], more than moderate atrioventricular valve regurgitation [HR: 4.82 (2.42–6.79), p = 0.003], and the need for first-stage palliative surgery [HR: 4.58 (1.64–10.76), p = 0.015] were independent risk factors for mortality.Conclusions: Despite even greater clinical diversity, the surgical outcomes of atrial isomerism with complex congenital heart disease are improving in China. The early and intermediate outcomes are comparable to many previous reports. Concomitant total anomalous pulmonary venous connection, moderate or severe atrioventricular valve regurgitation, and the need for a first-stage palliative surgery are still independent risk factors for mortality.

Myocardial Deformation in Fontan Patients Assessed by Cardiac Magnetic Resonance Feature Tracking: Correlation with Function, Clinical Course, and Biomarkers

Cardiac MR (CMR) is a standard modality for assessing ventricular function of single ventricles. CMR feature-tracking (CMR-FT) is a novel application enabling strain measurement on cine MR images and is used in patients with congenital heart diseases. We sought to assess the feasibility of CMR-FT in Fontan patients and analyze the correlation between CMR-FT strain values and conventional CMR volumetric parameters, clinical findings, and biomarkers. Global circumferential (GCS) and longitudinal (GLS) strain were retrospectively measured by CMR-FT on Steady-State Free Precession cine images. Data regarding post-operative course at Fontan operation, and medication, exercise capacity, invasive hemodynamics, and blood biomarkers at a time interval ± 6 months from CMR were collected. Forty-seven patients underwent CMR 11 ± 6 years after the Fontan operation; age at CMR was 15 ± 7 years. End-diastolic volume (EDV) of the SV was 93 ± 37 ml/m2, end-systolic volume (ESV) was 46 ± 23 ml/m2, and ejection fraction (EF) was 51 ± 11%. Twenty (42%) patients had a single right ventricle (SRV). In single left ventricle (SLV), GCS was higher (p < 0.001), but GLS was lower (p = 0.04) than in SRV. GCS correlated positively with EDV (p = 0.005), ESV (p < 0.001), and EF (p ≤ 0.0001). GLS correlated positively with EF (p = 0.002), but not with ventricular volumes. Impaired GCS correlated with decreased ventricular function (p = 0.03) and atrioventricular valve regurgitation (p = 0.04) at echocardiography, direct atriopulmonary connection (p = 0.02), post-operative complications (p = 0.05), and presence of a rudimentary ventricle (p = 0.01). A reduced GCS was associated with increased NT-pro-BNP (p = 0.05). Myocardial deformation can be measured by CMR-FT in Fontan patients. SLVs have higher GCS, but lower GLS than SRVs. GCS correlates with ventricular volumes and EF, whereas GLS correlates with EF only. Myocardial deformation shows a relationship with several clinical parameters and NT-pro-BNP.

Does Maintenance of Pulmonary Blood Flow Pulsatility at the Time of the Fontan Operation Improve Hemodynamic Outcome in Functionally Univentricular Hearts?

It is unclear whether residual anterograde pulmonary blood flow (APBF) at the time of Fontan is beneficial. Pulsatile pulmonary flow may be important in maintaining a compliant and healthy vascular circuit. We, therefore, wished to ascertain whether there was hemodynamic evidence that residual pulsatile flow at time of Fontan promotes clinical benefit. 106 consecutive children with Fontan completion (1999–2018) were included. Pulmonary artery pulsatility index (PI, (systolic pressure–diastolic pressure)/mean pressure)) was calculated from preoperative cardiac catheterization. Spectral analysis charted PI as a continuum against clinical outcome. The population was subsequently divided into three pulsatility subgroups to facilitate further comparison. Median PI prior to Fontan was 0.236 (range 0–1). 39 had APBF, in whom PI was significantly greater (median: 0.364 vs. 0.177, Mann–Whitney p < 0.0001). There were four early hospital deaths (3.77%), and PI in these patients ranged from 0.214 to 0.423. There was no correlation between PI and standard cardiac surgical outcomes or systemic oxygen saturation at discharge. Median follow-up time was 4.33 years (range 0.0273–19.6), with no late deaths. Increased pulsatility was associated with higher oxygen saturations in the long term, but there was no difference in reported exercise tolerance (Ross), ventricular function, or atrioventricular valve regurgitation at follow-up. PI in those with Fontan-associated complications or the requiring pulmonary vasodilators aligned with the overall population median. Maintenance of pulmonary flow pulsatility did not alter short-term outcomes or long-term prognosis following Fontan although it tended to increase postoperative oxygen saturations, which may be beneficial in later life.

Path ahead for ‘low risk’ adolescents living with a Fontan circulation

ObjectiveA high risk of morbidity and mortality is well documented in adults with a Fontan circulation. The difference in outcomes between those with and without significant morbidity at the time of transition to adult care has not been well characterised.MethodsWe analysed clinical outcomes in patients enrolled in the Australian and New Zealand Fontan Registry ≥16 years of age. Low risk (LR) Fontan patients were defined as those without history of sustained arrhythmia, thromboembolic event, transplantation, Fontan conversion, protein-losing enteropathy, plastic bronchitis, New York Heart Association class III/IV and/or moderate/severe atrioventricular valve regurgitation or ventricular dysfunction. Increased risk (IR) patients had one or more risk factor.ResultsInclusion criteria were met in 822 patients; mean age 26±8 years, median follow-up from age 16 was 9 years, 203 had atriopulmonary connection (APC) and 619 had total cavopulmonary connection (TCPC). Survival at 30 years was higher in the LR versus IR; 94% versus 82% (p=0.005), 89% versus 77% (p=0.07) for APC and 96% versus 89% (p=0.05) for TCPC. LR patients experienced less Fontan failure (HR 0.34, 95% CI 0.23 to 0.49, p<0.001) and ventricular dysfunction (HR 0.46, 95% CI 0.29 to 0.71, p=0.001) compared with IR patients. For LR TCPC patients, modelled survival projections at 60 years were 49%–67%.ConclusionsClinical outcomes for adolescents LR at transition to adult care are markedly superior to those who have established risk factors for Fontan failure, which is an important consideration when formulating individualised long-term risk estimates and counselling patients.

Abstract 15892: Reliability of Focused Cardiac Ultrasound in the Post-Operative Assessment of Patients With Congenital Heart Disease: A Single Center Experience

Introduction: Early detection of postoperative complications in children with congenital heart disease (CHD) is crucial. The utility of focused cardiac ultrasound (FoCUS) in the assessment of post-operative congenital cardiac surgical patients is not known. Objective: To evaluate the reliability of FoCUS in the assessment of children with CHD in the early post-operative period. Methods: A prospective observational cross-sectional study was performed in a single pediatric center. All FoCUS studies were performed by one imager within two hours of the paired echocardiographic (ECHO) study performed by a different imager. FoCUS studies were obtained using Philips Lumify R and ECHO studies utilized a high-end ultrasound machine (Philips Affiniti R ). Qualitative ventricular (right and left) function, pericardial effusion, pleural effusion, and degree of mitral regurgitation (MR) and tricuspid regurgitation (TR) were compared. All FoCUS and ECHO studies were sent for review in a random and blinded fashion to two independent noninvasive imaging cardiologists. Weighted k statistics were used to determine the level of agreement between FoCUS and ECHO, and between observers. Results: Twenty-three FoCUS studies were performed in 12 patients with a mean age of 16.6 months (range 0-96 months) within two weeks postoperatively. There was inter-observer agreement for ECHO on all parameters and inter-observer agreement for FoCUS on all parameters except for TR. The intra-observer agreement between FoCUS and ECHO for the two cardiologists was fair to moderate for ventricular function (k= 0.470, p< 0.05 and 0.340, p < 0.05), substantial for pericardial effusion (k = 0.617, p< 0.05 and 0.777, p< 0.05), and fair for MR (0.400, p< 0.05). There was no statistically significant agreement for TR and pleural effusion for both observers and MR for one observer. Conclusions: FoCUS demonstrated acceptable reliability in the assessment of ventricular function and presence of pericardial effusions, with a limited value in the assessment of atrioventricular valve regurgitation. This tool is valuable in the early post-operative evaluation of pediatric patients with congenital heart disease in the cardiac intensive care unit.

Abstract 15099: Limitations of Predicting Postoperative Left Atrioventricular Valve Regurgitation by Transesophageal Echocardiography

Introduction: After atrioventricular septal defect (AVSD) repair, the degree of post-repair left atrioventricular valve regurgitation (LAVVR) at discharge is associated with need for re-intervention. Knowledge of the relationship between post-repair transesophageal echocardiogram (TEE) and discharge transthoracic echocardiogram (TTE) LAVVR could influence intraoperative decision-making. At present, this relationship has not been well-defined and to assess it, we undertook a retrospective study of a large cohort of AVSD patients. Methods: Between 11/2012-12/2018, 96 AVSD patients underwent surgical repair. Data included patient demographics, clinical characteristics, preoperative LAVV anomalies, surgical procedure and outcomes. LAVVR was graded as less than moderate or moderate and greater with statistical blinding techniques employed. Cohen’s kappa statistics were calculated to measure interobserver variability. Association between parameters was tested using univariate analysis. Results: Median age and weight at surgery for complete AVSD patients (68%) was 5 months and 5.6 kg respectively; for partial AVSD (32%), median age and weight was 27 months and 11.9 kg respectively. The median interval between echo studies was 6 days (IQR 4-12 days) with median length of stay of 8 days (IQR 5-16 days). There were no deaths. Post-repair TEE revealed less than moderate LAVVR in 86 patients (90%) and moderate or greater in 10 (10%). Overall, there was a discrepancy in LAVVR seen at discharge in 25 patients (26%) with 23/25 (92%) demonstrating a higher grade of LAVVR. Two patients underwent reoperation before discharge due to severe LAVVR. In univariate analysis, significant predictors for LAVVR discrepancy were younger age (p=0.032) and lower weight (p=0.032) at repair; preoperative LAVVR grade was a significant predictor for worsening LAVVR (p=0.038). Conclusions: Discrepancy between LAVVR grade on post-repair TEE and discharge TTE was present in 26% of AVSD patients with the vast majority changing to a higher grade. This important finding with implications for intraoperative decision-making should prompt further investigations into preoperative LAVV anomalies, surgical technique and postoperative factors influencing valvar function.

Prevalence of pulmonary hypertension in adults after atrial switch and role of ventricular filling pressures

ObjectiveTo assess the prevalence of elevated systemic right ventricular (sRV) end-diastolic pressure and pulmonary arterial hypertension in adults with transposition of the great arteries (TGA) who have undergone atrial switch operation.MethodsForty-two adults (aged ≥18 years) with complete TGA and atrial switch palliation undergoing cardiac catheterisation between 2004 and 2018 at Mayo Clinic, MN, were identified. Clinical, echocardiographic and invasive haemodynamic data were abstracted from the medical charts and procedure logs.ResultsMean age was 37.6±7.9 years; 28 were male (67%). The Mustard operation was performed in 91% of individuals. Mean estimated sRV ejection fraction by echocardiography was 33.3%±10.9% and ≥moderate tricuspid (systemic atrioventricular valve) regurgitation was present in 15 patients (36%). Mean sRV end-diastolic pressure was 13.2±5.4 mm Hg. An sRV end-diastolic pressure >15 mm Hg was present in 35% of individuals whereas a pulmonary artery wedge pressure (PAWP) >15 mm Hg was seen in 59%. Mean pulmonary artery pressure ≥25 mm Hg was seen in 47.5% of patients with PAWP being >15 mm Hg in all but one patient.ConclusionIn adults after atrial switch, elevated sRV end-diastolic pressure was present in only one-third of patients whereas increased PAWP was seen in almost 60%. These findings are most likely related to a combination of decreased pulmonary atrial (functional left atrium) compliance and, in a subset of patients, pulmonary venous baffle obstruction. Elevation in pulmonary pressures was highly prevalent with concomitant elevation in PAWP being present in essentially all patients.

Mid-Term Follow-Up of Neonatal Neochordal Reconstruction of Tricuspid Valve for Perinatal Chordal Rupture Causing Severe Tricuspid Valve Regurgitation

Background: Papillary muscle rupture in the perinatal period is a rare event that leads to severe mitral or tricuspid insufficiency due to a flail leaflet. Neonatal tricuspid chordal reconstruction for this condition is rarely reported. Early recognition and treatment have the potential to be lifesaving. We present our surgical experience with five such patients, along with their midterm follow-up. Methods: Between August 2010 and November 2012, five neonates (aged 1-30 days) underwent surgery for severe atrioventricular valve regurgitation. All neonates had severe tricuspid regurgitation due to ruptured chordae. In addition, two had moderate mitral regurgitation; one due to ruptured chordae of the posterior mitral leaflet and the other due to prolapse of the anterior mitral leaflet. All underwent emergent surgery where the ruptured chordae to the anterior tricuspid leaflet were replaced with neochordae made with expanded polytetrafluoroethylene (ePTFE) suture. The mitral valve was repaired in two patients. Results: All patients survived surgery without the need for postoperative mechanical circulatory assist. Predischarge echocardiograms showed good coaptation of tricuspid and mitral leaflets with minimal regurgitation in all. At follow-up between 75 months to 102 months, four patients had excellent outcomes with less than mild tricuspid regurgitation. One child with flail tricuspid and mitral leaflets developed progressive tricuspid and mitral regurgitation requiring surgical re-repair at 20 months following the initial surgery. Conclusion: Repair of chordal rupture of the tricuspid valve in neonates using e PTFE neo-chordae can provide acute salvage and gratifying midterm results in the management of this potentially fatal condition.