Aims Aspirin, a widely used antiplatelet agent, irreversibly inhibits platelet cyclooxygenase-1 and reduce thromboxane-mediated platelet activation. Although it has been proved that aspirin played an important role in the primary and secondary prevention of cardiovascular diseases, its efficacy varies. The aim of our studywas to investigate the relationship betweenurinary 11-dehydro-thromboxane B2 (11dhTxB2) and clinical outcome in aged patients with coronaryartery disease (CAD).

Methods 108 aged CAD patients on 100 mg/d aspirin administration at least 12 month were enrolled in this study. Aspirin response was assessed using urinary11-DehydrothromboxaneB2 (11dhTxB2) measurement. Urinary11dhTxB2 >1500 pg/mg was defined as Aspirin Resistance (AR). The measured clinical outcomes were defined as the occurrence of cardiovascular events and death.

Results The mean age of all enrolled patients was 83.3 ± 10.5 years old. Baseline and post-treatment urinary 11-dhTXB2 levels are 3463 ± 2465 pg/mg and 1386 ± 1895 pg/mg, respectively. Prevalence of AR was 27.7% according to the defined criterion Urinary11dhTxB2 >1500 pg/mg. Within a mean follow-up time of 12 months, the outcomesoccurred more frequently in AR group as compared with no-AR patients (p < 0.05). After adjustment for the conventional risk factors for CAD, there still exists a significant association between AR based on urinary 11dhTxB2 level and clinical outcome (p < 0.05).

Conclusion Our research showed that 27.7% enrolled CAD patients meet the criterion of AR using urinary 11dhTxB2measurement. It’s noteworthy that AR status was significantly associated with higher incidence of cardiovascular events and death than no-AR patients (p < 0.05).