N-Terminal pro-B-type natriuretic peptide for predicting coronary disease and left ventricular hypertrophy in asymptomatic CKD not requiring dialysis

Background: N-Terminal pro-B-type natriuretic peptide (NT-proBNP) level predicts underlying heart disease in the general population. However, because NT-proBNP clearance may depend on renal function, the significance of an elevated level in patients with chronic kidney disease (CKD) without cardiac symptoms is uncertain. We sought to determine whether there is an association between NT-proBNP level and coronary artery disease (CAD) and left ventricular hypertrophy (LVH) in this population. Methods: We enrolled 207 ambulatory patients with CKD not on dialysis therapy. Medical records were reviewed for cardiac history and risk factors. NT-proBNP and troponin T (cTnT) levels were measured. Echocardiograms were analyzed from 99 patients. Results: NT-proBNP levels were elevated in 116 patients (56%), and 67 patients (33%) had experienced prior CAD events (myocardial infarction or revascularization). The prevalence of advanced age, diabetes, prior CAD events, myocardial injury (cTnT > 0.03 ng/mL [>0.03 μg/L]), and LVH increased, whereas glomerular filtration rate decreased, across quartiles of NT-proBNP levels. After adjustment for glomerular filtration rate, cTnT level, age, and diabetes, NT-proBNP remained an independent indicator of prior CAD events compared with quartile 1 (cTnT range, 4 to 116 pg/mL) for quartile 2 (range, 122 to 490 pg/mL): odds ratio, 1.6; 95% confidence interval, 0.5 to 5.0; for quartile 3 (range, 490 to 1,819 pg/mL): odds ratio, 5.3; 95% confidence interval, 1.7 to 16.2; and for quartile 4 (>1,975 pg/mL): odds ratio, 4.1; 95% confidence interval, 1.3 to 13.5. For patients with echocardiograms, NT-proBNP level predicted prior CAD events independent of LVH. Conclusion: NT-proBNP level elevation in asymptomatic patients with CKD reflects underlying ischemic heart disease and hypertrophy independent of renal function in a population with anticipated high cardiac morbidity.