Prognostic Value of the 6-Min Walk Test After Open-Heart Valve Surgery

Abstract

This single-center retrospective analysis aimed to evaluate the prognostic relevance of 6-min walk test (6MWT) in patients admitted to an in-hospital cardiovascular rehabilitation program after open-heart valve surgery. One hundred one patients able to perform a 6MWT within the first week of admission (time after surgery: 16 ± 8 d) were included (age 68 ± 11 y; 55% female; median left ventricular ejection fraction 55% [interquartile range: 50-60]; 51% after aortic valve surgery). Study endpoints were cardiovascular death and the combined outcome of cardiovascular death/cardiac hospitalization. Univariate and multivariate analyses were performed to analyze predictive value of the 6MWT. After a median follow-up of 27 mo, cardiovascular mortality was 9.9% while combined endpoint occurrence was 33%. Patients experiencing study endpoints had lower left ventricular ejection fraction, higher N-terminal prohormone of brain natriuretic peptide serum levels, and longer in-hospital stay (all P < .05). The 6MWT distance was a significant predictor of cardiovascular death (hazard ratio [HR] = 0.89, 95% CI: 0.81-0.97, P = .007) and cardiac hospitalizations (HR = 0.95, 95% CI: 0.90-0.99, P = .02). Even after adjusting for the relevant confounding variables of cardiovascular death and cardiac hospitalization, the adjusted HR = 0.88, 95% CI: 0.75-0.98, P = .028 and adjusted HR = 0.95, 95% CI: 0.90-0.99, P = .05, respectively. In patients admitted to an in-hospital cardiovascular rehabilitation program after open-heart valve surgery, 6MWT proved to be an independent prognostic tool, potentially allowing identification of high-risk patients for whom a more intensive and tailored in-hospital cardiovascular rehabilitation program should be designed and implemented in order to avoid unfavorable cardiovascular events.