Prognostic Impact of Plasma Brain Natriuretic Peptide for Cardiac Events in Elderly Patients with Congestive Heart Failure

Abstract

Background: Plasma brain natriuretic peptide (BNP) has been reported to be useful in determining the prognosis of patients with ischemic heart disease and cardiomyopathy. However, aging increases the level of plasma BNP; therefore, the prognostic impact of plasma BNP in elderly patients with congestive heart failure has not been fully established. Objective: We sought to determine whether plasma BNP could predict recurrent cardiac events in elderly patients with congestive heart failure. Methods: Forty-eight consecutive elderly patients (>65 years old) were enrolled in the present study. All patients were admitted with their first episode of congestive heart failure. Clinical characteristics, plasma BNP, left ventricular ejection fraction, and left ventricular mass index were compared between patients with and those without recurrent cardiac events. Results: During the follow-up period, twelve cardiac events were observed. The New York Heart Association functional class was signi- ficantly higher in patients with cardiac events than in those without (p < 0.05). The plasma BNP level in pa- tients with cardiac events was significantly higher than in those without (521.0 ± 156.0 vs. 126.8 ± 20.1 pg/ml, p < 0.001), despite more frequent treatment with angiotensin-converting enzyme inhibitors (75 vs. 28%, p < 0.05). The left ventricular ejection fraction was significantly lower and the left ventricular mass index higher in patients with cardiac events as compared with those without (38.1 ± 5.0 vs. 49.2 ± 2.4%, p < 0.05; 193.8 ± 14.3 vs. 132.6 ± 7.8 g/m², p < 0.001, respectively). The plasma BNP was selected as an independent factor associated with cardiac events besides New York Heart Association functional class, left ventricular ejection fraction, and left ventricular mass index using multivariate Cox proportional-hazards regression analysis (hazard ratio = 2.656, p < 0.05). The cardiac event rate was significantly higher in patients with a plasma BNP concentration >132 pg/ml using Kaplan-Meier analysis (p < 0.001). Moreover, the plasma BNP level correlated inversely with the length of time from hospital discharge to a cardiac event (r = –0.575, p < 0.05). Conclusion: Measuring the plasma BNP level before hospital discharge in elderly patients with congestive heart failure was more useful than other conventional examinations for predicting the recurrence of cardiac events.