Risk of cardiovascular complications depending on the level of platelet aggregation was studied in patients after coronary artery stenting. 100 patients with stable angina of II-IV functional class undergoing coronary artery stenting were included in the study. Platelet aggregation was estimated using optical aggregometry. In case of resistance to clopidogrel its dose was increased up to 150 mg a day. Clinical outcomes were evaluated after 6 and 12 months. It is ascertained that resistance to clopidogrel increases risk for unfavorable cardiovascular outcomes after 6 months by 42% and after 12 months - by 45%. Estimation of platelet aggregation activity is reasonable to perform before coronary angioplasty and in early terms after procedure to evaluate the efficacy of antiaggregant treatment.