Acetyl salicylic acid resistance in patients with chronic stable angina and the correlation with coronary risk factors

OBJECTIVE: To evaluate acetyl salicylic acid (ASA) resistance in patients with cardiovascular diseases and evaluate correlation with coronary risk factors.

METHODS: One hundred and twenty-four patients with stable coronary artery diseases (CAD) were enrolled in this cross sectional study from the outpatient clinic of the Department of Cardiology, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran, between May 2008 and August 2008. All patients had prior history of cardiovascular disease and were under treatment of 80 mg daily ASA for at least 7 days. Aspirin resistance was measured by urinary 11-dehydro-thromboxane beta-concentrations with an enzyme immunoassay kit.

RESULTS: Approximately 49.2% patients were resistant to ASA, 15.3% borderline response, and 35.5% were sensitive to ASA. Acetyl salicylic acid-resistant patients were more likely to be smokers and older ages (63% versus 45.4%) (37.7% less than 60 years, 53.7% between 60-69 years, and 63.3% aged >/=70 years). Other variables such as gender, diabetes mellitus, hypertension, cholesterol, triglyceride, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and hemoglobin levels were not significantly associated with aspirin resistance.

CONCLUSION: Acetyl salicylic acid resistance was present in a high number of patients with chronic stable angina. Moreover, advanced age and smoking had a direct influence on the aspirin resistance.