Abstract 14508: Vorapaxar for Secondary Prevention after Myocardial Infarction According to Aspirin Dose - Insights from the TRA2°P-TIMI 50 Trial
Background: In patients with a recent MI, aspirin (ASA) dose varies considerably depending on local practice patterns. Vorapaxar inhibits thrombin-mediated platelet activation by blocking the protease-activated receptor (PAR)-1. The risk and benefit of adding vorapaxar according to different ASA dose for long-term secondary prevention in stable patients with prior MI are unknown.
Methods: TRA2P-TIMI 50 trial patients with history of MI within the prior 2 weeks to 12 months as the qualifying event (N=17,779) were randomized to vorapaxar or placebo. Event rates are presented as 3-yr KM estimates. Baseline ASA dose was categorized as <100 mg daily, 100-162 mg, and >162 mg. The 331 pts not receiving ASA were excluded.
Results: 6988 pts (40%) received <100 mg ASA daily, 7704 pts (44%) 100-162 mg, and 2755 (16%) > 162 mg. The majority of patients on >162 mg were from N. America (80.6%), though most patients from N. America (56%) were on a dose <=162g daily. Pts receiving >162 mg were younger, but more likely to have peripheral vascular disease or prior revascularization. The beneficial effect of vorapaxar was similar across ASA dose groups with ~20% reductions in the risk of CV death/MI/stroke and CV Death/MI (p for interaction 0.98 and 0.94, respectively). The increase in bleeding risk among pts treated with voraxapar was also similar across ASA groups (moderate/severe bleeding [p for interaction=0.38]), with no increase in bleeding risk for patients receiving >100 mg daily. (Figure)
Conclusions: In patients with a recent MI, there remains considerable variability in the ASA dose selected for secondary prevention. Regardless of baseline ASA dose, vorapaxar reduced the risk of major cardiovascular events by ~20%. The relative risk of bleeding was not higher with vorapaxar in the higher ASA doses.
- © 2012 by American Heart Association, Inc.