Late outcome, therapy and systemic ventricular function in patients with a systemic right ventricle: data of the German National Register for Congenital Heart Defects

Background: Adults with systemic right ventricle have a significant risk for long-term complications such as arrhythmias or heart failure. Methods: A nationwide retrospective study based on the German National Register for Congenital Heart Disease was performed. Patients with transposition of the great arteries after atrial switch operation or congenitally corrected TGA were included. Results: Two hundred and eight-five patients with transposition of the great arteries after atrial switch operation and 95 patients with congenitally corrected transposition of the great arteries were included (mean age 33 years). Systolic function of the systemic ventricle was moderately or severely reduced in 25.5 % after atrial switch operation and in 35.1% in patients with congenitally corrected transposition. Regurgitation of the systemic atrioventricular valve was present in 39.5% and 43.2% of the cases, respectively. A significant percentage of patients also had a history for supraventricular or ventricular arrhythmias. However, polypharmacy of cardiovascular drugs was rare (4.5%) and 38.5 % of the patients did not take any cardiovascular medication. The amount of cardiovascular drugs taken was associated with NYHA class as well as systemic right ventricular dysfunction. Patients with congenitally corrected transposition were more likely to receive pharmacological treatment than patients after atrial switch operation. Conclusion: A significant portion of patients with systemic right ventricle suffer from a relevant systemic ventricular dysfunction, systemic atrioventricular valve regurgitation, and arrhythmias. Despite this, medication for heart failure treatment is not universally used in this cohort. This emphasises the need for randomised trials in patient with systemic right ventricle.

A Comprehensive Functional Analysis in Patients after Atrial Switch Surgery

Background Long-term course after atrial switch operation is determined by increasing right ventricular (RV) insufficiency. The aim of our study was to investigate subtle functional parameters by invasive measurements with conductance technique and noninvasive examinations with cardiac magnetic resonance imaging (CMR). Methods We used invasive (pressure–volume loops under baseline conditions and dobutamine) and noninvasive techniques (CMR with feature tracking [FT] method) to evaluate RV function. All patients had cardiopulmonary exercise testing (CPET). Results From 2011 to 2013, 16 patients aged 28.2 ± 7.3 (22–50) years after atrial switch surgery (87.5% Senning and 12.5% Mustard) were enrolled in this prospective study. All patients were in New York Heart Association (NYHA) class I to II and presented mean peak oxygen consumption of 30.1 ± 5.7 (22.7–45.5) mL/kg/min. CMR-derived end-diastolic volume was 110 ± 22 (78–156) mL/m2 and RV ejection fraction 41 ± 8% (25–52%). CMR-FT revealed lower global systolic longitudinal, radial, and circumferential strain for the systemic RV compared with the subpulmonary left ventricle. End-systolic elastance (Ees) was overall reduced (compared with data from the literature) and showed significant increase under dobutamine (0.80 ± 0.44 to 1.89 ± 0.72 mm Hg/mL, p ≤ 0.001), whereas end-diastolic elastance (Eed) was not significantly influenced (0.11 ± 0.70 to 0.13 ± 0.15 mm Hg/mL, p = 0.454). We found no relevant relationship between load-independent conductance indices and strain or CPET parameters. Conductance analysis revealed significant mechanical dyssynchrony, higher during diastole (mean 30 ± 4% baseline, 24 ± 6% dobutamine) than during systole (mean 17 ± 6% baseline, 19 ± 7% dobutamine). Conclusions Functional assessment of a deteriorating systemic RV remains demanding. Conductance indices as well as the CMR-derived strain parameters showed overall reduced values, but a significant relationship was not present (including CPET). Our conductance analysis revealed intraventricular and predominantly diastolic RV dyssynchrony.

Validation and Feasibility of Echocardiographic Assessment of Systemic Right Ventricular Function: Serial Correlation With MRI

Background: Inherent to its geometry, echocardiographic imaging of the systemic right ventricle (RV) is challenging. Therefore, echocardiographic assessment of systemic RV function may not always be feasible and/or reproducible in daily practice. Here, we aim to validate the usefulness of a comprehensive range of 32 echocardiographic measurements of systemic RV function in a longitudinal cohort by serial assessment of their correlations with cardiac magnetic resonance (CMR)-derived systemic RV ejection fraction (RVEF).Methods: A single-center, retrospective cohort study was performed. Adult patients with a systemic RV who underwent a combination of both CMR and echocardiography at two different points in time were included. Off-line analysis of echocardiographic images was blinded to off-line CMR analysis and vice versa. In half of the echocardiograms, measurements were repeated by a second observer blinded to the results of the first. Correlations between echocardiographic and CMR measures were assessed with Pearson's correlation coefficient and interobserver agreement was quantified with intraclass correlation coefficients (ICC).Results: Fourteen patients were included, of which 4 had congenitally corrected transposition of the great arteries (ccTGA) and 10 patients had TGA late after an atrial switch operation. Eight patients (57%) were female. There was a mean of 8 years between the first and second imaging assessment. Only global systemic RV function, fractional area change (FAC), and global longitudinal strain (GLS) were consistently, i.e., at both time points, correlated with CMR-RVEF (global RV function: r = −0.77/r = −0.63; FAC: r = 0.79/r = 0.67; GLS: r = −0.73/r = −0.70, all p-values < 0.05). The ICC of GLS (0.82 at t = 1, p = 0.006, 0.77 at t = 2, p = 0.024) was higher than the ICC of FAC (0.35 at t = 1, p = 0.196, 0.70 at t = 2, p = 0.051) at both time points.Conclusion: GLS appears to be the most robust echocardiographic measurement of systemic RV function with good correlation with CMR-RVEF and reproducibility.

Clinical Course Long After Atrial Switch: A Novel Risk Score for Major Clinical Events

Background Patients with transposition of the great arteries corrected by an atrial switch operation experience major clinical events during adulthood, mainly heart failure (HF) and arrhythmias, but data on the emerging risks remain scarce. We assessed the risk for events during the clinical course in adulthood, and provided a novel risk score for event‐free survival. Methods and Results This multicenter study observed 167 patients with transposition of the great arteries corrected by an atrial switch operation (61% Mustard procedure; age, 28 [interquartile range, 24–36] years) for 13 (interquartile range, 9–16) years, during which 16 (10%) patients died, 33 (20%) had HF events, defined as HF hospitalizations, heart transplantation, ventricular assist device implantation, or HF‐related death, and 15 (9%) had symptomatic ventricular arrhythmias. Five‐year risk of mortality, first HF event, and first ventricular arrhythmia increased from 1% each at age 25 years, to 6% (95% CI, 4%–9%), 23% (95% CI, 17%–28%), and 5% (95% CI, 2%–8%), respectively, at age 50 years. Predictors for event‐free survival were examined to construct a prediction model using bootstrapping techniques. A prediction model combining age >30 years, prior ventricular arrhythmia, age >1 year at repair, moderate or greater right ventricular dysfunction, severe tricuspid regurgitation, and mild or greater left ventricular dysfunction discriminated well between patients at low (<5%), intermediate (5%–20%), and high (>20%) 5‐year risk (optimism‐corrected C‐statistic, 0.86 [95% CI, 0.82–0.90]). Observed 5‐ and 10‐year event‐free survival rates in low‐risk patients were 100% and 97%, respectively, compared with only 31% and 8%, respectively, in high‐risk patients. Conclusions The clinical course of patients undergoing atrial switch increasingly consists of major clinical events, especially HF. A novel risk score stratifying patients as low, intermediate, and high risk for event‐free survival provides information on absolute individual risks, which may support decisions for pharmacological and interventional management.

Abstract 16879: Utility of Transthoracic Echocardiography in Adult Patients With D-Transposition of the Great Arteries and Atrial Switch Operation

Introduction: Per 2018 ACC AHA adult congenital heart disease guidelines, routine transthoracic echocardiography (TTE) is recommended for follow-up in patients with d-transposition of the great arteries (dTGA) after atrial switch operation at least annually. Little data are available to suggest utility in clinical management with frequent surveillance, either with or without symptoms. Hypothesis: We hypothesized that frequent TTEs would not lead to significant clinical changes in management and that TTEs performed for symptoms would lead to more detection of pathology and clinically relevant management decisions. Methods: We conducted a retrospective review of all echocardiograms performed for dTGA patients corrected with the atrial switch procedure at Texas Children’s Hospital from 2000-2009 to obtain baseline TTEs and 2010-2019 to analyze for changes in clinical management, associated with TTE performance. Results: We identified 50 patients with dTGA and atrial switch operation with 54% Mustard operation. A total of 333 echocardiograms were performed (6.7/person), 30% (100) with symptoms. The average age at time of all TTEs was 35 +/- 11 years. Most frequent symptoms were palpitations (n=39), dyspnea (n=30), and fatigue (n=27). Changes in management occurred after 9% of studies (10/100 of symptomatic, 21/233 asymptomatic patients, p = NS). Most of these were medication changes (n=18, 11 asymptomatic) and advanced imaging (n=12, 9 asymptomatic). Invasive management after TTE was rare (1 baffle stenting in asymptomatic patient) but after advanced imaging included 4 baffle stent implantations (3 asymptomatic). The interval between TTEs was 1.2 +/- 0.9 years, regardless of symptoms. Conclusions: In dTGA patients after atrial switch operation, routine screening TTEs and symptomatic TTEs had similar yield in detecting pathology leading to a clinical change in management. TTE and subsequent advanced imaging preceded invasive intervention (baffle stenting) in 10% of patients, mostly asymptomatic. Less frequent surveillance TTEs in asymptomatic and advanced imaging in symptomatic dTGA patients with atrial switch operation is cost-effective and should be considered .