Role of N-terminal pro-B-type natriuretic peptide in risk stratification in patients presenting in the emergency room.

BACKGROUND Natriuretic peptides are promising markers in diagnosing acute and chronic heart failure and assessing prognosis in these patients. Increasing routine use to unselected patients is challenged by false-positive results. The aims of this study were to assess (a) the distributions of N-terminal B-type natriuretic peptide (NT-proBNP) values in various diagnostic groups, (b) factors that influence NT-proBNP, and (c) the value of NT-proBNP in risk stratification in unselected emergency room (ER) patients. METHODS NT-proBNP was measured in 876 unselected consecutive patients [mean (SD) age, 58 (18) years; 53% male] attending the ERs of 2 university hospitals and 1 community hospital. Diagnoses, age, sex, hemoglobin, creatinine (CREA), C-reactive protein (CRP), troponin T, and intensity of care were documented. In a subset consisting of all 417 patients at 1 center, in-hospital follow-up was completed with respect to a complicated clinical course, including intensive care treatment and death. RESULTS NT-proBNP was significantly increased in patients with cardiac diagnoses or histories compared with patients with only pulmonary or other diagnoses. In patients with other diagnoses, NT-proBNP values increased significantly with the number of atherosclerotic risk factors (P=0.044). Age, renal function, CRP, and to a much lesser extent, hemoglobin significantly influenced NT-proBNP values. The amount of care was positively correlated with NT-proBNP (P<0.001). Classification and regression tree analysis showed a superior impact of NT-proBNP for identification of high-risk patients. CONCLUSIONS NT-proBNP is a promising marker for identification of patients with structural heart disease in the ER and a suitable tool for risk stratification. Its use in the ER should be limited to clearly clinically defined patient groups at present to avoid a potential excess of additional diagnostic procedures in positive but asymptomatic patients.