Impact of right ventricular systolic function after heart transplantation on exercise capacity

Right ventricular (RV) systolic parameters are difficult to assess in heart transplant recipients (HTRs) compared to healthy people because of discordant data, and their impact on exercise capacity remains undefined. We sought to retrospectively assess the impact of RV systolic function on exercise capacity after heart transplantation.

We analyzed data from 61 HTRs who underwent transthoracic echocardiography (TTE), cardiac magnetic resonance imaging (CMR), and exercise capacity assessment by 6-minute walking test (6MWT) and cardiopulmonary exercise testing (CPET) at 1- and 2-year follow-ups.

Transthoracic echocardiography RV longitudinal systolic function including tricuspid annular plan systolic excursion (TAPSE), peak systolic S' wave tricuspid annular velocity (PSVtdi) and RV free wall longitudinal strain was decreased at 1 year (respectively, 15 ± 3 mm, 10 ± 3 cm/s, and -19 ± 5%) and at 2 years (respectively, 15 ± 3 mm, 10 ± 2 cm/s, and -20 ± 5%) with no significant difference between both evaluations; meanwhile, RV ejection fraction (RVEF) measured by CMR was preserved. Mean percentage of predicted peak oxygen consumption was altered, but improved between the first and second year (55 ± 18 vs 60 ± 18%, P = .038). PSVtdi was weakly correlated with 6MWT distance (r = .426, P = .017) and RVEF with the predicted distance at 6MWT (r = .410, P = .027) at the 1-year follow-up.

Despite decreasing values, RV longitudinal systolic function has a weak impact on exercise capacity of HTRs. PSVtdi and RVEF are the most pertinent parameters to assess the impact of RV systolic function on exercise capacity after heart transplantation. These results should lead to redefine normal RV systolic function thresholds for HTRs.