Prognostic value of serial B-type natriuretic peptide testing during follow-up of patients with unstable coronary artery disease

Context: Elevated concentrations of B-type natriuretic peptide (BNP) at presentation in patients with acute coronary syndrome (ACS) are associated with long-term mortality. Few data exist regarding serial assessment of BNP levels during follow-up. Objective: To determine whether concentrations of BNP at study entry (prior to hospital discharge for ACS) and at outpatient follow-up at 4 months and 12 months are associated with subsequent clinical outcomes. Design, Setting, and Patients: Prospective observational substudy of 4497 patients with non-ST-elevation or ST-elevation ACS who were enrolled in phase Z of the A to Z trial, which was conducted in 41 countries at 322 acute care hospitals between 1999 and 2003. Main Outcome Measure: Death from any cause or new onset of congestive heart failure (CHF) through 2 years. Results: Levels of BNP were available in 4266 patients at study entry (prior to hospital discharge), 3618 patients at 4 months, and 2966 patients at 12 months. During follow-up there were 230 deaths and 163 incident cases of CHF. Adjusting for age, sex, index event, renal function, hypertension, prior heart failure, and diabetes, elevated levels of BNP (>80 pg/mL) were associated with subsequent death or new CHF when measured at study entry (111 [21%] vs 246 [7%]; adjusted hazard ratio [HR], 2.5; 95% confidence interval [CI], 2.0-3.3), at 4 months (34 [19%] vs 125 [4%]; adjusted HR, 3.9; 95% CI, 2.6-6.0), and at 12 months (19 [11%] vs 37 [1%]; adjusted HR, 4.7; 95% CI, 2.5-8.9). Patients with newly elevated levels of BNP at 4 months were at increased risk of death or new CHF (10 [15%] vs 105 [3%]); HR, 4.5; 95% CI, 2.3-8.6). Patients with elevated levels of BNP at study entry and with BNP levels lower than 80 pg/mL at 4 months tended to have only modestly increased risk (HR, 1.7; 95% CI, 1.0-2.9) compared with patients with BNP levels lower than 80 pg/mL at both visits. Conclusions: Serial determinations of BNP levels during outpatient follow-up after ACS predict the risk of death or new CHF. Changes in BNP levels over time are associated with long-term clinical outcomes and may provide a basis for enhanced clinical decision making in patients after onset of ACS.