Ticagrelor vs. clopidogrel in non-ST-elevation acute coronary syndromes

The aim of this study was to evaluate the bradyarrhythmic events associated with ticagrelor combination therapy in the management of patients presenting with non-ST-segment elevation myocardial infarction (NSTEMI).

The study comprised 300 patients with NSTEMI who were treated via percutaneous coronary intervention (PCI). Patients were randomly assigned to two groups: the clopidogrel group (initial dose of 300 mg and then maintenance dose of 75 mg once daily, n = 151) and the ticagrelor group (initial dose of 180 mg and then maintenance dose of 90 mg twice daily, n = 149). All patients were followed up in the outpatient clinic. Follow-up included 12-lead electrocardiography and 24-h Holter monitoring performed 1, 6, and 12 months after the revascularization procedure.

Of the 300 patients, 112 patients (36.7 %) had a decrease in heart rate at the 12-month follow-up. Of these, 80 patients were in the ticagrelor group (53.3 %) vs. 32 patients in the clopidogrel group (24.7 %; p < 0.05). However, the difference was not statistically significant at the 1-month and 6-month follow-up visits. After adjusting for potential confounders, the reduction in heart rate with ticagrelor combination therapy remained independently associated with a reduced risk of major adverse cardiovascular events (hazard ratio, 2.1; 95 % CI, 1.90-2.23), while ticagrelor therapy reduced the risk to a level equivalent to that of patients in the clopidogrel group.

Ticagrelor can lower the resting heart rate of patients and cause bradyarrhythmias in the 12th month after PCI.