Abstract 16314: Late Survival After Atrial Switch in Transposition of the Great Arteries: Results From a Multi-institutional Study

Abstract

Background: Although several factors have been cited for risk stratification in patients with simple transposition of the great arteries (dTGA), no single predictor emerges consistently. We aimed to assess survival and determine factors associated with survival in a large cohort of dTGA adults with atrial switch. Methods and Results: We included 1,169 dTGA adults (median age 28.1 years, 38.7% female) under regular follow-up at 28 institutions between 2002 and 2019. The primary outcome was a composite of death, mechanical circulatory support (MCS) and heart transplant. During a median follow-up of 9.2 [IQR 5.5-14.2] years, 67 (5.7%) patients died, six (0.5%) patients underwent MCS and 21 (1.8%) had a heart transplant. Cumulative incidence of composite endpoint at 15 years was 12.8% [95% CI 9.8 - 15.7], see Figure). Median age at time of primary outcome was 39.5 [IQR 33.9 - 45.1] years. Leading causes of death were worsening of heart failure (34%), non-cardiac (21%) and sudden unexplained death (12%). In multivariable Cox analyses for baseline variables, age, VSD, ventricular arrhythmia and heart failure admission were each associated with increased risk of the outcome, whereas prior pacemaker (26% of patients) was not. New pacemaker implantation was performed in 107 (9.1%), ICD in 109 (9.3%), and cardiac surgery in 35 (3%) patients. Patients who died were more likely to develop arrhythmias, be admitted for heart failure or require surgery during follow-up. Conclusion: In this large contemporary cohort of dTGA adults after atrial switch, late survival was excellent and seemed to be determined by arrhythmia and heart failure-related complications. Few patients underwent advanced heart failure therapies. Figure. Cumulative incidence of the composite primary outcome (MCS, heart transplant or death) over a period of 15 years from first visit at an adult congenital heart disease clinic since 2002. Shading represents upper and lower 95% confidence limits.