Aspirin resistance in patients with acute coronary syndrome. Part 1

Abstract

Aim. To evaluate the prevalence of aspirin resistance, its clinical features, potential solutions, and prognostic role in patients with acute coronary syndrome (ACS). Material and methods. The study included 51 patients with ACS and ST segment elevation (STEACS) and 49 ACS patients without ST segment elevation (non-STEACS). All participants received aspirin in a standard dose of 100 mg/d. Platelet aggregation (PA) was measured with a laser assay method and arachidonic acid (0,5 mg/dl) as an inductor. Aspirin resistance was diagnosed if PA was at least 20% at Day 7 of aspirin treatment. Results. Aspirin resistance was observed in 11% of the patients receiving aspirin in a standard dose of 100 mg/d. The majority of aspirin-resistant patients had STEACS, therefore, the data for this group were analysed in detail. Major clinical characteristics of aspirin-resistant and aspirin-responding patients were similar. After the in vitro test with aspirin, to determine the pharmacokinetic type of aspirin resistance, the medication dose was increased to 300 mg/d. The comparison group included 10 patients with STEACS, receiving aspirin in the dose of 100 mg/d. Thirty days later, PA was significantly reduced in both aspirin-resistant groups, therefore, the aspirin dose increase did not affect PA dynamics. In aspirin-resistant patients, prognosis was slightly worse than in their aspirinresponding peers. Conclusion. Aspirin resistance was more prevalent in STEACS patients. By Day 30, PA was substantially reduced. Increasing aspirin dose to 300 mg/d did not affect PA dynamics.

Keywords

• acetylsalicylic acid
• aspirin resistance
• acute coronary syndrome
• platelet aggregation
• inflammation markers
• genetic polymorphisms