Advanced heart failure and heart transplantation in adult congenital heart disease in the current era.

BACKGROUND: Adults with congenital heart disease (ACHD) may undergo heart transplantation (HTx) despite increased risk of poor short-term outcomes due to factors including surgical complexity and antibody sensitization. We assessed the clinical characteristics and outcomes of patients with ACHD in the current era referred for HTx at a single high-volume transplant center. METHODS: From 2010 to 2020, 37 ACHD patients were evaluated for HTx. ACHD HTx recipients were compared to non-ACHD HTx recipients matched for age, sex, listing status, and prior cardiac surgery. RESULTS: Of the 37 patients with ACHD, eight (21.6%) were declined for HTx. Of 29 ACHD patients listed, 19 (65.5%) underwent HTx. Compared with non-ACHD HTx controls, the ACHD HTx recipients had more treated cellular (21.1% vs. 15.8%, P = .010) and antibody-mediated (15.8% vs. 10.5%, P = .033) rejection. There was no difference in hospital readmission or allograft vasculopathy at 1 year. There was a nonsignificant higher 1-year mortality in ACHD HTx recipients (21.1% vs. 7.9%, P = .21). CONCLUSION: At a high-volume transplant center, ACHD patients undergoing HTx appear to have a marginally higher risk of rejection, but no significant increase in 1-year mortality. With careful selection and management, HTx for patients with ACHD may be feasible in the current era.

Pocket proteins critically regulate cell cycle exit of the trabecular myocardium and the ventricular conduction system.

During development, the ventricular conduction system (VCS) arises from the trabecular or spongy myocardium. VCS and trabecular myocytes proliferate at a significantly slower rate than compact zone myocardial cells, establishing a transmural cell cycle gradient. The molecular determinants of VCS/trabecular myocyte cell cycle arrest are not known. Given the importance of pocket proteins (Rb, p107 and p130) in mediating G0/G1 arrest in many cell types, we examined the role of this gene family in regulating cell cycle exit of the trabecular myocardium and ventricular conduction system. Using a combinatorial knockout strategy, we found that graded loss of pocket proteins results in a spectrum of heart and lung defects. p107/p130 double knockout (dKO) hearts manifest dysregulated proliferation within the compact myocardium and trabecular bases, while the remaining trabecular region cell cycle exits normally. Consequently, dKO hearts exhibit defective cardiac compaction, septal hyperplasia and biventricular outflow tract obstruction, while the VCS appears relatively normal. Loss of all three pocket proteins (3KO) is necessary to completely disrupt the transmural cell cycle gradient. 3KO hearts exhibit massive overgrowth of the trabecular myocardium and ventricular conduction system, which leads to fetal heart failure and death. Hearts carrying a single pocket protein allele are able to maintain the transmural cell cycle gradient. These results demonstrate the exquisite sensitivity of trabecular and conduction myocytes to pocket protein function during ventricular chamber development.