Prognostic Role of Cardiopulmonary Exercise Testing in Pulmonary Hypertension: A Systematic Review and Meta-Analysis

Introduction: Several studies have evaluated the relation between variables of cardiopulmonary exercise testing (CPET) and major clinical events in pulmonary hypertension (PH) patients, although the results were conflicting. The main objective of this study was to investigate the prognostic value of the CPET derived parameters on all-cause mortality or urgent transplantation in PH patients. Material and Methods: A meta-analysis of time-to-event outcomes were performed from observational studies that evaluated the predictive value of CEPT-related variables [peak oxygen uptake (VO₂) and the ventilation to CO₂ production slope (VE/VCO₂)] in PH patients, reporting data from mortality or urgent transplantation, after searching the PubMed/MEDLINE, Embase, Science Direct, Scopus, Google Scholar, and Cochrane databases. A random-effects meta-analysis model was then applied. Results: Nine eligible studies, including 986 patients, were identified and considered eligible for the quantitative analyses. This meta-analysis showed that high peak VO₂ was associated with a lower mortality or transplant occurrence (HR: 0.81; 95% CI: 0.78–0.85, I² = 29%). In addition, high VE/VCO₂ slope was associated with a higher incidence of the primary endpoint (HR: 1.04; 95% CI: 1.02-1.06, I² = 78%). The sensitivity analysis showed that the results were robust. Conclusions: Our data suggest that in a population with PH the CPET-related variables have predictive capacity regarding mortality and the risk of transplantation. Future studies should establish the best cut-off points for these CPET-related variables.