Prognostic value of B-type natriuretic peptide in patients with chronic mitral regurgitation undergoing surgery: mid-term follow-up results

OBJECTIVES: The prognostic value of B-type natriuretic peptide (BNP) for surgical outcome in patients with mitral regurgitation (MR) has not been studied. The purpose of this study was to determine the prognostic value of BNP in patients with chronic severe MR, undergoing mitral valve surgery. METHODS: In total, 117 patients with chronic severe MR undergoing surgery were evaluated from the MR registry of Seoul National University Hospital. Patients were excluded if they had acute MR or acutely decompensated heart failure, and significant renal, pulmonary, coronary or other significant valvular heart disease. The plasma BNP level assay and echocardiographic studies were done before surgery. Study endpoint was a composite of cardiac death and cardiac hospitalization during follow-up. RESULTS: The median duration of the follow-up was 4.5 years, and the study endpoint was reached in 11 (9.4%) patients. Receiver-operating characteristic curve analysis yielded an optimal cut-off point of 125 pg/ml for BNP that distinguished patients with poor prognosis. Kaplan-Meier survival analysis with the log-rank test and multivariate Cox proportional hazards model showed that patients with BNP ≥125 pg/ml had a worse clinical outcome after surgery (log rank 7.606, P = 0.006; adjusted hazard ratio = 5.536 [95% confidence interval 1.189-25.788], P = 0.029). CONCLUSIONS: Among patients with chronic severe MR undergoing mitral valve surgery, BNP independently predicts the poor clinical outcome. The BNP measurement should be considered in the risk stratification of these patients.