The relation between aspirin resistance and mean platelet volume in patients with significant coronary artery stenosis

Objective: Aspirin is the basis of antiplatelet treatment in patients with coronary artery disease, but aspirin resistance is seen in a wide range (0.4%-83.3%) in these patients. Mean platelet volume (MPV) is a parameter of platelet activation. In this study, we aimed to investigate the relation between MPV and aspirin resistance in patients taking aspirin regularly (100 mg or 300 mg per day) and who were found to have significant coronary artery stenosis angiographically. Study Design: 140 patients with angiographically significant coronary stenosis (lesions > % 50) were enrolled to study (77 men, 63 women, mean age: 51.9+/-6.9). Before coronary angiography venous blood samples of patients were taken for MPV measurements. The patients were divided to two groups accordig to their MPV values: group 1, patients with MPV > 10,5 fL and group 2, patients with MPV <= 10,5 fL. The patients' answers to aspirin was determined by PFA-100 (platelet function anayliser) method. In this system patients whose collagen/ epinephrine closing time were under 165 seconds were accepted as resistant to aspirin. Results: 36 patients (25.7%) were found to be resistant to aspirin. When patients were investigated according to their MPV values, there was statistically significant difference between aspirin resistance of two groups (35 % and 13%; p: 0,002). When aspirin resistant and and aspirin sensitive patients were investigated according to their MPV values there was significant difference between the groups (in group A MPV was 9,08+/-1,34 while MPV was 10,3+/-1,89, in group B, p: 0,03). There was also statistically significant relation between two groups in correlation analyses (r: 0,24, p: 0.01). Conclusion: In our study we found out that aspirin resistance rates were higher in patients with significant coronary artery disease who had higher MPV values. We think that we can determine aspirin resistance in patients with sigfinicant coronary artery disease and higher MPV values by PFA-100 device in a short time and so we can give antiaggregan treatments more effectively