Long-Term Impact of Tricuspid Valve Intervention on Survival and Atrioventricular Valve and Ventricular Function After Fontan Completion in Hypoplastic Left Heart Syndrome

J. Moon¹, T. Lancaster¹, V. Sood², J. Romano³, R. Ohye^1
1University of Michigan, Ann Arbor, Michigan ²University of Michigan Mott Children's Hospital, Ann Arbor, Michigan ³University of Michigan Congenital Heart Center, Ann Arbor, Michigan

Purpose: Tricuspid regurgitation (TR) is a significant survival risk in hypoplastic left heart syndrome (HLHS). Optimal surgical techniques, associated long-term valve and ventricular function, and survival outcomes remain unclear.

Methods: A retrospective single institutional study was conducted. The data was collected by chart review, the National Death Index, and the Scientific Registry of Transplant Recipients. This study included HLHS patients, who completed Fontan in our institution from 1985 through 2017. Exclusion criteria were 1) Patients who died or failed their single ventricle palliation before Fontan and 2) Patients who underwent tricuspid valve replacement without attempted repair.
The primary outcomes were Fontan takedown and transplant-free survival. Secondary outcomes were the conditional cumulative incidence of tricuspid valve (TV) failure (≥ moderate TR or surgical TV intervention) and ventricular failure (≥ moderate ventricular dysfunction or mechanical circulatory support) by removing early TV failure (≥moderate TR at the discharge after Fontan) from the original cohort. The outcomes were stratified by the non-TV intervention (Non-TVI) and TV intervention group (TVI).

Results: A total of 485 HLHS were included. Among them, 83 underwent tricuspid valve intervention with 107 procedures (at stage II, 33 subjects; between stage II and Fontan, 15: at Fontan, 49; after Fontan, 11). Surgical techniques included partial annuloplasty with posterior leaflet obliteration (68), commissuroplasty (23), cleft closure (11), ring annuloplasty (9), and other (4). Fifty-seven subjects (13%) had residual ≥moderate TR after the Fontan, regardless of TV intervention.
The transplant and Fontan takedown-free survival was 62% at 20 years. TVI showed significantly lower survival at 15 years than non-TVI (77% vs 60%, P=0.01). However, single TV intervention patients showed comparable survival with the non-TVI (Non: 77% vs. single: 79% vs. repeat: 47%, P< 0.001). By multivariable analysis, repeat TVI (HR 3.2, P=0.03), ventricular dysfunction after Fontan (HR 6.1, P=0.004), and prolonged chest tube drainage (HR 2.1, P=0.002) were significant risk factors for survival.
The conditional cumulative incidence of TV failure was 22.9% at 20 years, which was higher in the TVI than non-TVI (11 % vs 34% at 10 years, P< 0.001). The conditional cumulative incidence of ventricular failure was 12% at 20 years, which was also higher in the TVI cohort (7 % vs 28% at 15 years, P=0.003).

Conclusion: Repeat TVI was associated with inferior survival after Fontan. Although the single TVI group showed comparable survival outcomes to non-TVI, successful single TVI affected adversely the long-term valve and ventricular function after Fontan.

Identify the source of the funding for this research project: None