Long-term outcomes of heart transplantation in adults with congenital heart disease: The impact of single-ventricle versus biventricular physiology

Objective: Congenital heart disease is a risk factor for mortality after orthotopic heart transplantation; however, the impact of preoperative circulation type and primary congenital heart disease diagnosis remains poorly delineated. Methods: We retrospectively reviewed patients with adult congenital heart disease aged 16 years or more who underwent orthotopic heart transplantation at our institution between 2008 and 2022. Patients were categorized as having single-ventricle or biventricular circulation. The primary end point was 5-year post-transplant survival. Results: Sixty-one patients with adult congenital heart disease (single-ventricle: n = 26 [42.6%], % ], biventricular: n = 35 [57.4%]) % ]) underwent orthotopic heart transplantation at 33.7 [interquartile range, 19.1-48.7] years. The most common congenital heart disease diagnosis was hypoplastic left heart syndrome (n = 11, 42.3%) % ) in the single-ventricle group 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, patients in the single-ventricle group were younger (18.5 [interquartile range, 17.6-32.3] years vs 45.0 [interquartile range, 33.0-52.2] years, P <. 001) and more likely to have biopsy-proven cirrhosis (46.2% % vs 14.3%, %, P = . 01) and protein-losing enteropathy (42.3% % vs 2.9%, %, P <. 001). Patients in the single-ventricle group also had longer bypass times (223.4 +/- 65.3 minutes vs 187.4 +/- 59.5 minutes, , P = . 03) and longer durations of mechanical ventilatory support (3.5 [interquartile range, 2.0-6.0] days vs 1.0 [interquartile range, 1.0-2.0] days, , P < . 001). Operative mortality was comparable (11.5% % vs 8.6%, % , P = 1). Median follow-up was 6.0 [interquartile range, 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 = . 03), as was freedom from major rejection (58.3% % +/- 10.2% % vs 84.0% % +/- 6.6%, %, P = . 02). In univariable analysis, hypoplastic left heart syndrome and Fontan circulation were risk factors for post-transplant mortality (hypoplastic left heart syndrome: hazard ratio, 5.0, , P <. 001; Fontan: hazard ratio, 3.5, P = . 03). Conclusions: Adult patients with congenital heart disease undergoing heart transplant 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 orthotopic heart transplantation decision-making in this complex cohort.