Impact of the history of congestive heart failure on the utility of B-type natriuretic peptide in the emergency diagnosis of heart failure: results from the Breathing Not Properly Multinational Study.

Purpose: B-type natriuretic peptide is known to correlate with hemodynamic state, presence and severity of congestive heart failure, and prognosis. Although low-range B-type natriuretic peptide less than 100 pg/mL has a high negative predictive value (90%), and high-range B-type natriuretic peptide greater than 500 pg/mL has a high positive predictive value (87%), there remains some ambiguity in the interpretation of results in the medium range (100-500 pg/mL). We hypothesized that taking into account the history of congestive heart failure along with other clinical variables would be helpful in this range of B-type natriuretic peptide levels.

Method: The Breathing Not Properly Multicenter Study was an international, 7-center, prospective study including 1475 patients with a mean age of 63 years (57% were male, and 54% were female); 35% of patients with a history of congestive heart failure were enrolled, and a final diagnosis of congestive heart failure was made in 46%. The index criteria was defined as positive if any 2 index findings (ie, history of coronary artery disease, lower extremity edema, pulmonary edema, cephalization of the pulmonary arteries, and cardiomegaly) were present.

Results: The interval likelihood ratios (LR) for low, medium, and high B-type natriuretic peptide ranges are 0.13, 1.85, and 8.1, respectively. For medium B-type natriuretic peptide levels a positive history of congestive heart failure makes the diagnosis of congestive heart failure more probable with a cumulative LR of 4.3. Also in this range a positive index criterion was strongly indicative of congestive heart failure even in the absence of a history of congestive heart failure (LR 3.3). Where there are both a positive history of congestive heart failure and a positive index criteria for the medium B-type natriuretic peptide group, the cumulative LR (10.2) is similar to that of a high B-type natriuretic peptide level (8.1).

Conclusion: Even in the medium range (100-500 pg/mL), when using the history of congestive heart failure and index criteria, B-type natriuretic peptide can be a powerful diagnostic tool in the hands of clinicians in the emergency department.