Usefulness and predictive value of circulating NT-proBNP levels to stratify patients for referral and priority treatment in a specialized outpatient heart failure center

Background: Serum natriuretic peptide levels are useful diagnostic and prognostic markers in patients with acute decompensated heart failure, but have been little used to stratify urgency of treatment in the outpatient situation. Objectives: To examine the use of natriuretic peptide to guide priority of patient referral to a heart failure center. Methods: We analyzed data from 70 consecutive patients with chronic heart failure (NYHA class 2-4) referred for first evaluation in a specialized outpatient heart failure center. Serum NT-proBNP was measured at the initial patient visit. We examined correlates and predictive value of mid- and upper tertile NT-proBNP for mortality in comparison with other known prognostic indicators using univariate and multivariate logistic regression analysis. Results: Mortality at 6 months was 26.0% in patients with upper tertile (> 1958 pg/ml) NT-proBNP, 8.7% in the middle tertile group and 0% in the lowest tertile (P = 0.017). Patients with upper tertile serum NT-proBNP levels (group 3) had lower left ventricular ejection fraction, were more often in atrial fibrillation (P = 0.04) and more often had renal failure (P = 0.03). Age-adjusted logistic regression analysis identified upper tertile serum NT-proBNP level as the strongest independent pedictor of 6 month mortality with a sixfold rist of early death (adjusted odds ratio 6.08, 95% confidence interval 1.58-47.13, P = 0.04). NT-proBNP was a more powerful predictor of prognosis than ejection fraction and other traditional outcome markers. Conclusions: In heart failure patients referred to an outpatients specialized heart failure center, an upper tertile NT-proBNP level identified patients at high risk for mortality. A single high > 550 pg/ml NT-proBNP measurement appears to be useful for selecting patients for care in a heart failure center, and a level > 2000 pg/ml for assigning patients to high priority management.