The effect of acetylsalicylic acid on thrombin generation in healthy volunteers.

This study assessed the effect of low-dose aspirin (81 mg) on thrombin generation in healthy volunteers using the calibrated automated thrombogram (CAT). This single-center prospective crossover study involved healthy volunteers, each serving as their own control. After Institutional Review Board approval and informed consent, healthy participants were administered aspirin (81 mg daily) for 7 days. Blood samples were collected at baseline, after the 7-day aspirin regimen, and 2 weeks postaspirin discontinuation. Platelet-poor plasma (PPP) samples were analyzed using CAT to measure endogenous thrombin potential (ETP) and other CAT parameters. The primary endpoint was change in ETP from baseline to after 7 days of aspirin. Data were analyzed with paired t tests. Data from 18 participants (ages 27-54) showed no significant change in ETP after aspirin administration (primary endpoint). Specifically, mean (standard deviation) ETP at baseline and on-aspirin were 1750 (237) vs. 1832 (301) nmol/l min, respectively. Secondary CAT parameters (lag time, peak thrombin generation, time to peak, and velocity index) also showed no significant differences. We did not observe a significant effect of low-dose aspirin (81 mg) for 7 days on any measure of thrombin generation in healthy volunteers. This study's controlled design in healthy subjects contrasts with previous studies that focused on patients where confounding effects of comorbidities and concomitant medications may have influenced the results.