B-Type Natriuretic Peptide Predicts Morbidity and Long-Term Mortality in Coronary Artery Bypass Grafting and Valve Surgery

Abstract

Objective To assess whether B-type natriuretic peptide (BNP) levels are a useful predictor of morbidity and mortality as well as long-term survival in patients after coronary artery bypass grafting (CABG) and valve surgery. Methods A retrospective review of CABG and/or valve surgery patients from 2012 to 2015 at a single center was conducted. A total of 432 patients were identified (CABG, 295 patients; valve, 82 patients; and CABG + valve, 55 patients). B-type natriuretic peptide levels were divided into quartiles (Q1-Q4). Mortality data were available for up to 3.4 years after surgery. Results B-type natriuretic peptide quartile was independently associated with any complication on multivariate analysis. Patients in Q4 were at highest risk (adjusted odds ratio, 3.81; P = 0.047 vs Q1). There was a significant association between BNP quartile and time to death (logrank χ2, 8.30; P = 0.04) with greatest association 9 months postoperatively. B-type natriuretic peptide quartile was significantly associated with time to death in Cox regression in Q2 (hazard ratio [HR], 3.73 (1.04–13.44); P = 0.044) and Q4 (HR, 4.33 (1.14–16.44); P = 0.031). Q3 also had a higher risk of death (HR, 3.5 vs Q1); however, this was only significant at a trend level (P = 0.06). Using a risk model generated from logistic regression, we determined that the highest risk group had relative risk of complications 30 times higher than the lowest risk group. Conclusions B-type natriuretic peptide levels are an independent predictor of morbidity after CABG and/or valve surgery regardless of type of procedure or on/off bypass usage. B-type natriuretic peptide levels also correlate with time to death, highlighting the need for sustained follow-up and heart failure management to improve survival in patients with elevated BNP levels presenting for all cardiac surgery.