Prevalence of Aspirin Resistance among Jordanian Patients with Cardiovascular Disease

Introduction: Despite the wide range of aspirin indications, there is a considerable amount of patients do not respond to aspirin, who also are referred to as aspirin non-responders or aspirin resistant patients. Aims and objectives: This study was carried out to prospectively evaluate the prevalence of aspirin resistance in Jordanian patients with cardiovascular disease and further clarify the clinical predictors of aspirin resistance. Materials and methods: Biochemical aspirin response was assessed based on the measurements of urinary11-dehydro thromboxane B2 (11-dhTxB2) levels using FDA approved diagnostic kit. Patients taking aspirin (75-325mg) for at least 7 days were prospectively enrolled from all stable cardiac patients presenting at Jordan University hospital outpatient clinics. Results: Eighty six (86) patients were enrolled in this study. Another twenty four healthy individuals were enrolled to function as a control group. The mean urinary levels of 11- dhTxB2/creatinine were significantly lower almost 3- times in patients in the primary and secondary aspirin prevention group compared with the control group (1567.58 vs. 4236.19 pg/mg, p-value >0.005). Thirty-one patients were found to be aspirin resistant with a prevalence of 36%. Conclusion: Our findings of aspirin resistance are particularly important given the large number of patients using this medication for prevention of atherothrombotic events. These results indicate that aspirin resistance should be diagnosed so that individuals with no response to aspirin can receive an alternative or an additional antiplatelet therapy.