The aim of the research was to evaluate impact of adding clopidogrel to aspirin therapy in patients with acute coronary syndrome (ACS) without ST segment elevation with aspirin resistance (AR), diagnosed by means of
aggregation with arachidonic acid on indices of platelet aggregation with different inductors and clinical course of disease. We included 74 patients with ACS without ST segment elevation which received aspirin 75–160 mg
daily at the time of hospitalization for at least 6 months. As a result of platelet aggregation induction with arachidonic acid patients were allocated to groups of existing AR (n=26) and without it (n=49), which subsequently were divided into subgroups according to the treatment. To analyze the clinical course within 21 days or at the time of discharge we estimated frequency of severe complications of ACS: paroxysmal or
persistent atrial fibrillation, sustained ventricular tachycardia or ventricular fibrillation and non-fatal (re-)infarction. It was established that in patients with biochemical AR dual antiplatelet therapy, compared with aspirin monotherapy, contributes to more pronounced reduction of spontaneous aggregation, which is associated with decrease in total frequency of non-fatal (re-)infarction or death within 21 days by 27.7 %.
Efficiency of dual aspirin and clopidogrel therapy in patients with ACS may be due to the influence of the latter on several platelet receptors, other than adenosindiphosphate.