Amino Terminal Pro–B-Type Natriuretic Peptide, Secondary Stroke Prevention, and Choice of Antithrombotic Therapy
Background and Purpose—Because of its association with atrial fibrillation and heart failure, we hypothesized that amino terminal pro–B-type natriuretic peptide (NT-proBNP) would identify a subgroup of patients from the Warfarin–Aspirin Recurrent Stroke Study, diagnosed with inferred noncardioembolic ischemic strokes, where anticoagulation would be more effective than antiplatelet agents in reducing risk of subsequent events.
Methods—NT-proBNP was measured in stored serum collected at baseline from participants enrolled in Warfarin–Aspirin Recurrent Stroke Study, a previously reported randomized trial. Relative effectiveness of warfarin and aspirin in preventing recurrent ischemic stroke or death over 2 years was compared based on NT-proBNP concentrations.
Results—About 95% of 1028 patients with assays had NT-proBNP below 750 pg/mL, and among them, no evidence for treatment effect modification was evident. For 49 patients with NT-proBNP >750 pg/mL, the 2-year rate of events per 100 person-years was 45.9 for the aspirin group and 16.6 for the warfarin group, whereas for 979 patients with NT-proBNP ≤750 pg/mL, rates were similar for both treatments. For those with NT-proBNP >750 pg/mL, the hazard ratio was 0.30 (95% confidence interval: 0.12–0.84; P=0.021) significantly favoring warfarin over aspirin. A formal test for interaction of NT-proBNP with treatment was significant (P=0.01).
Conclusions—For secondary stroke prevention, elevated NT-proBNP concentrations may identify a subgroup of ischemic stroke patients without known atrial fibrillation, about 5% based on the current study, who may benefit more from anticoagulants than antiplatelet agents.
Clinical Trial Registration—This trial was not registered because enrollment began before 2005.
- Received September 3, 2012.
- Accepted December 6, 2012.
- © 2013 American Heart Association, Inc.