Abstract 8537: Twice Daily Dosing of Aspirin Ii Biologically More Effective in Patients with Type 2 Diabetes Mellitus and Coronary Artery Disease
Background The efficacy of aspirin in preventing cardiovascular events appears to be lower in DM patients than in general population. We have previously demonstrated a time-dependent aspirin efficacy suggesting that once daily aspirin does not provide 24h stable biological efficacy, mainly in patients with DM, inflammatory markers and active smokers.
Objective: To compare biological efficacy of 150 mg/day aspirin given once daily (OPD) as compared to 150mg/day divided in 75 mg in the morning and 75 mg in the evening (BID) in a cross over study in patients with DM.
Methods: A randomized monocentric prospective study with cross over is realized in 92 patients with DM and previous acute coronary syndrome with high risk of biological aspirin resistance (elevated hsCRP, elevated fibrinogen or current smoking). Blood samples are analyzed the morning just before aspirin intake in a blinded fashion. Primary endpoint is the percentage of aspirin resistant patients measured by light transmission aggregometry using arachidonic acid 0.5mg/mL (LTA-AA). PFA-100 testing, using epinephrine cartridges is also performed. Patients are considered resistant if aggregation is ≥20% with LTA-AA or if PFA-100 epinephrine closure time was ≤193 seconds.
Results: Mean HbA1c is 7.4%±1.2% and 43% of patients are treated with insulin. Mean age is 64±10 y.o., 85% are male, 34% are active smokers and 52% are treated with clopidogrel. There is no difference in mean platelet count (270±78G/L), fibrinogen (3.6±1.0g/L) and hsCRP (5.5±6.9mg/L). Using LTA-AA, mean residual aggregation was 19.7±15.4% on OPD versus 11.9±10.4% on BID (p<0.001). Biological aspirin resistance (residual aggregation ≥ 20%) significantly decrease from 42% on OPD to 17% on BID corresponding to a decrease of 62% (p=0.0005). Interestingly, 24 patients resistant on OPD became sensitive on BID. Inversely, only one patient resistant on BID become sensitive on BID. Based on PFA-100, 41% of patients were resistant on OPD versus 29% on BID (p=0.12). Similar results are found in patients with or without clopidogrel.
Conclusions In diabetic patients with elevated inflammatory markers or active smoking, the same dose of aspirin BID is biologically more effective than OPD.
- © 2011 by American Heart Association, Inc.