Association of B-Type Natriuretic Peptide With Survival in Patients With Degenerative Mitral Regurgitation

Background Studies suggesting that B-type natriuretic peptide (BNP) may predict outcomes of mitral regurgitation (MR) are plagued by small size, inconsistent etiologies, and lack of accounting for shifting normal BNP ranges with age and sex. Objectives This study assessed the effect of BNP activation on mortality in a large, multicenter cohort of patients with degenerative MR. Methods In 1,331 patients with degenerative MR, BNP was prospectively measured at diagnosis and expressed as BNPratio (ratio to upper limit of normal for age, sex, and assay). Initial surgical management was performed within 3 months of diagnosis in 561 patents. Results The cohort had a mean age of 64 ± 15 years, was 66% male, and had a mean ejection fraction 64 ± 9%, mean regurgitant volume 67 ± 31 ml, and low mean Charlson comorbidity index of 1.09 ± 1.76. Median BNPratio was 1.01 (25th and 75th percentiles: 0.42 to 2.36). Overall, BNPratio was a powerful, independent predictor of mortality (hazard ratio: 1.33 [95% confidence interval: 1.15 to 1.54]; p < 0.0001), whereas absolute BNP was not (p = 0.43). In patients who were initially treated medically (n = 770; 58%), BNPratio was a powerful, independent, and incremental predictor of mortality after diagnosis (hazard ratio: 1.61 [95% confidence interval: 1.34 to 1.93]; p < 0.0001). Higher BNP activation was associated with higher mortality (p < 0.0001). All subgroups, particularly severe MR, incurred similar excess mortality with BNP activation. After initial surgical treatment (n = 561, 42%) BNP activation did not impose excess long-term mortality (p = 0.23). Conclusions In patients with degenerative MR, BNPratio is a powerful, independent, and incremental predictor of long-term mortality under medical management. BNPratio should be incorporated into the routine clinical assessment of patients with degenerative MR.