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.Clinical Trials Registration ClinicalTrials.gov Identifier: NCT00251576.