Cardiac transplantation in adult congenital heart disease: a narrative review

Background and Objective: As more children with congenital heart disease survive to adulthood, adult congenital heart disease (ACHD) prevalence will increase (currently similar to 1 million US patients). Heart failure (HF) accounts for 26-42% of ACHD deaths. The rate of ACHD heart transplantations (ACHD HTx) is also increasing. We describe the ACHD HTx recipient/candidate cohort, analyze ACHD HTx outcomes, identify ACHD HTx specific challenges, and discuss opportunities to better serve more patients with ACHD HF. Methods: PubMed literature search including articles published from 2010-2023. Reviewed 89 studies, 67 included. Our search focused on the challenges of ACHD HTx and potential solutions. Key Content and Findings: ACHD HTx recipients are young (median age 35 years, IQR 24-46). 87-95% of ACHD HTx recipients had prior cardiac surgery. The most common underlying diagnoses include transposition of the great arteries (31%) and Fontan/Glenn circulation (28%). 63% of listed ACHD HTx candidates received a transplant within one year of listing. Post-transplant 1-year survival is 80%, 5-year survival 74%, and 10-year survival 59%. There are 4 unique ACHD HTx challenges: (I) Difficulty in assessing pulmonary hypertension, resulting in some centers selecting oversized donor hearts. However, selecting oversized hearts does not improve post-operative mortality and could prolong waitlist time. (II) Increased immunologic sensitization, increasing rejection risk. Desensitization therapy has enabled sensitized HTx recipients to enjoy outcomes similar to non-sensitized recipients. (III) Procedural complexity with similar to 30% of cases requiring additional surgical reconstruction. Detailed multidisciplinary planning, extensive imaging, and transferring the patient into the operating room early can help manage the complexities and reduce organ ischemic time. (IV) Increased intraoperative bleeding due to patients' surgical histories and circulatory collaterals. Preoperative collateral coil embolization and select utilization of hypothermic circulatory arrest can help reduce bleeding. Additional Fontan specific challenges include extensive great artery repair, liver failure, plastic bronchitis, and protein loss enteropathy. Finally, given limited donor heart availability, mechanical circulatory support is a promising technology for patients with ACHD HF. Conclusions: The prevalence of ACHD HTx is slowly but steadily increasing. The operational complexity of ACHD HTx can be managed, and the majority of recipients have excellent outcomes (59% 10-year survival).