Prognostic Importance of Health Status Versus Functional Status in Heart Failure and Secondary Mitral Regurgitation

Abstract Objectives This study sought to understand the extent to which health status and exercise capacity are independently associated with long-term outcomes in patients with heart failure (HF) and secondary mitral regurgitation (MR). Background Secondary MR in patients with HF leads to impaired health status (Kansas City Cardiomyopathy Questionnaire Overall Summary Score [KCCQ-OS]) and exercise capacity (6-minute walk distance [6MWD]), both of which improve after transcatheter mitral valve repair (TMVr). Methods The study used data from the COAPT trial (N = 604) to examine the association of baseline KCCQ-OS and 6MWD with 2-year mortality and HF hospitalization, adjusting for treatment arm and patient factors. We also examined the association of change in KCCQ-OS and 6MWD from baseline to 1 month with risk of outcomes from 1 month to 2 years. Interactions of KCCQ-OS and 6MWD with treatment assignment were explored. Results Mean baseline KCCQ-OS was 53 ± 23 points, and 6MWD was 240 ± 125 meters. In models including both measures, greater baseline 6MWD (but not KCCQ-OS) was associated with reduced 2-year mortality (HR per 125 meters: 0.75, 95% CI: 0.61-0.92). When stratified by treatment group, both baseline KCCQ-OS and 6MWD were independently associated with HF hospitalization in patients treated with medical therapy, whereas only KCCQ-OS was associated with HF hospitalization in patients treated with TMVr. In separate analyses, 1-month improvements in KCCQ-OS and 6MWD were each associated with lower subsequent risk of mortality and HF hospitalization, independent of treatment group. Conclusions Among patients with HF and severe secondary MR, assessment of both health status and exercise capacity provide complementary prognostic information for patients with HF and severe secondary MR—both before and after TMVr. (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation [The COAPT Trial]; NCT01626079 )