Long-Term Outcomes of Heart Transplantation in Adults with Congenital Heart Disease: The Impact of Single-Ventricle Versus Biventricular Physiology

Objective Congenital heart disease (CHD) is a risk factor for mortality after orthotopic heart transplantation (OHT); however, the impact of preoperative circulation type and primary CHD diagnosis remains poorly delineated. Methods We retrospectively reviewed adult CHD (ACHD) patients ≥16 years who underwent OHT at our institution between 2008 and 2022. Patients were categorized as having single-ventricle or biventricular circulation. The primary endpoint was 5-year post-transplant survival. Results Sixty-one patients with ACHD (single-ventricle: n=26[42.6%]), biventricular: n=35[57.4%]) underwent OHT at 33.7[IQR,19.1-48.7] years. The most common CHD diagnosis was hypoplastic left heart syndrome (HLHS) (n=11,42.3%) in single-ventricle patients and congenitally corrected transposition of the great arteries (n=7,20.0%) in the biventricular group. Twenty-four patients previously underwent Fontan palliation. At transplant, single-ventricle patients were younger (18.5[IQR,17.6-32.3] vs. 45.0[IQR,33.0-52.2]) years,P<0.001) and were more likely to have biopsy-proven cirrhosis (46.2% vs. 14.3%,P=0.01) and protein losing enteropathy (42.3% vs. 2.9%,P<0.001). Single-ventricle patients also had longer bypass times (223.4±65.3 vs. 187.4±59.5 minutes,P=0.03) and longer durations of mechanical ventilatory support (3.5[IQR,2.0-6.0] vs. 1.0[IQR,1.0-2.0] days,P<0.001). Operative mortality was comparable (11.5% vs. 8.6%,P=1). Median follow-up was 6.0[IQR, 2.4-10.0] years. Five-year survival was worse in the single-ventricle group (66.0±10.0% vs. 91.3±4.8%,P=0.03), as was freedom from major rejection (58.3±10.2% vs. 84.0±6.6%,P=0.02). In univariable analysis, HLHS and Fontan circulation were risk factors for post-transplant mortality (HLHS: HR:5.0,P<0.001; Fontan: HR:3.5,P=0.03). Conclusions ACHD heart transplant recipients with single-ventricle physiology experienced a more complicated post-transplant course, with worse long-term survival and freedom from rejection. Multicenter studies are required to guide OHT decision-making in this complex cohort.