Relevance of short-term variation of B-type natriuretic peptide in patients with clinically stable heart failure

BACKGROUND: In patients with clinically stable chronic heart failure, circulating B-type natriuretic peptide (BNP) levels may exhibit considerable variation over a period of a few days. The aim of this study was to evaluate the clinical impact of this phenomenon. METHODS: In 23 patients with clinically stable mild-to-moderate systolic heart failure [median (interquartile range) 72 (64-77) years, left ventricular ejection fraction 30 (27-40)%] and a history of previous hospitalization for heart failure, BNP was measured at two time points [T1 and T2, interval 5 (3-7) days] for calculation of the absolute change in BNP concentrations between T1 and T2 (Delta BNP; irrespective of whether there was a decrease or increase). Follow-up for rehospitalization was 436 (407-458) days. RESULTS: In the group overall, Delta BNP was 26 (9-116) pg/ml [19 (10-28)% of the value at T1]. During follow-up, 8/23 (35%) patients were rehospitalized. BNP concentrations at T1 [340 (187-533) vs. 210 (108-606) pg/ml; P = 0.33] and T2 [328 (125-491) vs. 259 (89-536) pg/ml; P = 0.51] were similar in patients who were rehospitalized and those who were not; however, Delta BNP was higher in patients requiring rehospitalization [98 (36-186) vs. 19 (6-93) pg/ml; P = 0.04]. Patients with Delta BNP < 26 pg/ml had a longer rehospitalization-free survival than those with Delta BNP >= 26 pg/ml (log rank P = 0.02). Sensitivity and specificity of Delta BNP >= 26 pg/ml for the prediction of rehospitalization were 88% and 67% respectively. CONCLUSIONS: In this small study among patients with clinically stable heart failure, higher Delta BNP over a period of a few days was associated with a higher likelihood of rehospitalization during follow-up.