Association between the TAPSE/PASP ratio and exercise capacity in heart transplant candidates with advanced heart failure

Background Peak oxygen consumption (VO₂) is a key determinant of heart transplant eligibility in advanced heart failure (HF), reflecting integrated cardiopulmonary performance and long-term prognosis. We aimed to evaluate the association between the tricuspid annular plane systolic excursion to pulmonary artery systolic pressure (TAPSE/PASP) ratio—a non-invasive marker of right ventricular–pulmonary arterial (RV–PA) coupling—and exercise capacity, as measured by peak VO₂, in heart transplant candidates. Methods We retrospectively analyzed 384 consecutive patients with advanced HF listed for heart transplantation between 2021 and 2023. All underwent transthoracic echocardiography, cardiopulmonary exercise testing (CPET), and right heart catheterization (RHC). Patients with LVEF >25%, severe pulmonary disease, or contraindications to CPET/RHC were excluded. Participants were stratified into tertiles by TAPSE/PASP ratio. A directed acyclic graph (DAG) guided confounder selection for multivariable linear regression assessing the association between TAPSE/PASP and peak VO₂. Cox proportional hazards models evaluated the relationship between TAPSE/PASP and a composite endpoint of death, left ventricular assist device implantation, or transplantation. Results The mean age of the patients was 50 ± 11 years; 14% were female. Higher TAPSE/PASP tertiles were associated with longer exercise duration, higher peak VO₂, and better ventilatory efficiency. In adjusted regression analysis, TAPSE/PASP was strongly associated with peak VO₂ (effect size: 6.7; 95% CI: 5.1–8.4; p < 0.001). Over a median follow-up of 865 days, higher TAPSE/PASP was independently associated with lower event rates, with an adjusted hazard ratio of 0.78 (95% CI: 0.68–0.90; p < 0.001) per 0.1-unit increase in TAPSE/PASP. Conclusion TAPSE/PASP, beyond its role as a surrogate of RV function, is strongly associated with exercise capacity and, in secondary analyses, with long-term outcomes in advanced HF. Incorporating TAPSE/PASP into transplant evaluation protocols may enhance risk stratification and help identify patients who require closer monitoring and tailored management.