Aims Aspirin is an irreversible cyclooxygenase inhibitor, which prevents the production of thromboxane A2 in platelet. Nevertheless, its efficacy varies from one patient to another. The aim of our studywas to investigate the correlation between urinary 11-dehydro-thromboxane B2 (11dhTxB2) and clinical outcomes in aged patients coronaryartery disease (CAD).

Methods 145 aged patients were enrolled in this study, 108 with CAD, and 37 without CAD were defined as controls. Aspirin response was assessed by urinary 11dhTxB2 measurement and urinary11dhTxB2 >1500 pg/mg was defined as aspirin resistance (AR). All enrolled patients were assigned into AR and Non-AR group according to urinary11dhTxB2 level. The measured clinical outcomes were defined as the occurrence of cardiovascular events and death.

Results The mean age of CAD patients and controls were 83.3 ± 10.5 and 77.4 ± 9.4 years old, separately. The mean baseline urinary 11dhTxB2 of controls (3404 ± 2196 pg/mg) was significantly lower than CAD patients (3463 ± 2465 pg/mg) (p < 0.001). After 100 mg/d aspirin administration, 11dhTxB2 level in CAD patients (1386 ± 1895 pg/mg) and controls (1227 ± 2090 pg/mg) were significantly lower than their baseline level (p < 0.001, respectively). Prevalence of AR was 27.7% and 3.3% in CAD patients and controls. The incidence of clinical outcome in AR patients was much higher than no-AR group in CAD patients (p < 0.05).

Conclusion Both baseline urinary 11dhTxB2 levels and prevalence of AR were significantly higher in CAD patients as compared with controls (p < 0.01, respectively). The incidence of clinical outcome was higher in AR patients with CAD. (p < 0.05).