Prognostic Accuracy of B-Natriuretic Peptide Measurements and Coronary Artery Calcium in Asymptomatic Subjects (from the Early Identification of Subclinical Atherosclerosis by Noninvasive Imaging Research [EISNER] Study)

Abstract

B-type natriuretic peptide (BNP) has prognostic implications in patients with acute and chronic cardiac symptoms. Its prognostic role in asymptomatic patients with evidence of subclinical disease remains unclear. The population of this study included 2,458 asymptomatic adults (47% women) with an average Framingham risk score of 8.8 +/- 7% who underwent computed tomographic evaluation of coronary artery calcium (CAC). BNP levels were measured using the Triage CardioProfilER panel method. Cox proportional-hazards models were used to estimate time to a cardiovascular (CV) event (n = 84; 16 deaths, 12 myocardial infarctions, 8 cerebrovascular accidents or transient ischemic attacks, and 48 diagnoses of incident symptomatic coronary disease). Relative risk was calculated. The median follow-up time was 3.9 years (25th and 75th percentiles 2.9 and 4.0). The relative hazard for a CV event ranged from 2.2 to 7.5 for BNP values of 40 to 99.9 and > or =100 pg/ml (p <0.0001) compared to BNP <40 pg/ml. Similarly, CAC score was also highly predictive of CV events, with elevated hazard ratios of 2.8- to 48.7-fold for scores of 11 to 100 to > or =1,000 (p <0.0001) compared to no CAC. In a stepwise model, BNP was the second greatest estimator of CV outcomes (p = 0.016) after CAC (p <0.0001), even in models that included blood pressure and age. Hypertension, age > or =65 years, and CAC contained 28.4%, 40.7%, and 56.8%, respectively, of BNP risk. The combination of BNP > or =100 pg/ml and CAC score > or =400 identified 52.4% and 35.7% of CV events in patients with hypertension and in elderly patients beyond the Framingham risk score. In conclusion, BNP and CAC are independently predictive of CV events.