Response to Letter Regarding Article, “N-Terminal Pro–B-Type Natriuretic Peptide Testing Improves the Management of Patients With Suspected Acute Heart Failure: Primary Results of the Canadian Prospective Randomized Multicenter IMPROVE-CHF Study”
We are grateful of the comments provided by Chung et al about the observation in our study1 that N-terminal pro–B-type natriuretic peptide (NT-proBNP) levels were increased in patients with prior history of heart failure and/or left ventricular dysfunction even when dyspnea was not due to heart failure. Our findings were consistent with those from previous studies demonstrating a modest increase in BNP/NT-proBNP levels in these patients compared with those without a history of heart failure.2,3 In the study of Chung et al,4 the performance of BNP as measured by receiver operating characteristic curve was less optimal in patients with prior history of heart failure or left ventricular dysfunction. They did not, however, provide information among the 71 patients with dyspnea not due to heart failure on potential differences in demographic characteristics such as age between their patients with prior heart failure and those without, although for their entire group the receiver operating characteristic curves were similar between those below and those above the median age. Results from the N-terminal Pro-BNP Investigation of Dyspnea in the Emergency Department (PRIDE) study demonstrated improved diagnostic utility if the cut points were stratified by age.2 Previous BNP/NT-proBNP values would be useful but are frequently unavailable. We do concur with Chung et al on the challenge of making a diagnosis of heart failure in elderly patients with comorbid conditions including prior heart failure.
Dr Moe has received a research grant and honoraria from Roche Diagnostics Canada. Dr Januzzi has received research grants, honoraria, and consulting fees from Roche Diagnostics, Dade-Behring, and Ortho Clinical Diagnostics. H. Zowall has received a research grant and consulting fees from Roche Diagnostics Canada.
Moe GW, Howlett J, Januzzi JL, Zowall H. N-terminal pro–B-type natriuretic peptide testing improves the management of patients with suspected acute heart failure: primary results of the Canadian prospective randomized multicenter IMPROVE-CHF study. Circulation. 2007; 115: 3103–3110.
Januzzi JL Jr, Camargo CA, Anwaruddin S, Baggish AL, Chen AA, Krauser DG, Tung R, Cameron R, Nagurney JT, Chae CU, Lloyd-Jones DM, Brown DF, Foran-Melanson S, Sluss PM, Lee-Lewandrowski E, Lewandrowski KB. The N-terminal Pro-BNP investigation of dyspnea in the emergency department (PRIDE) study. Am J Cardiol. 2005; 95: 948–954.
Maisel AS, Krishnaswamy P, Nowak RM, McCord J, Hollander JE, Duc P, Omland T, Storrow AB, Abraham WT, Wu AH, Clopton P, Steg PG, Westheim A, Knudsen CW, Perez A, Kazanegra R, Herrmann HC, McCullough PA. Rapid measurement of B-type natriuretic peptide in the emergency diagnosis of heart failure. N Engl J Med. 2002; 347: 161–167.