Safety outcomes of ticagrelor among patients with STE-ACS post streptokinase therapy-a retrospective observational study.

From the restriction of access to primary percutaneous coronary intervention, about 46% of patients with ST-elevation acute coronary syndrome (STE-ACS) received fibrinolytic therapy as a reperfusion strategy; streptokinase is frequently used in Thailand. Despite the guidelines recommending potent P2Y12 inhibitors among these patients, the data are limited, especially among patients with STE-ACS post streptokinase therapy. The study was proposed to describe factors for P2Y12 inhibitors selection and evaluate outcomes of pharmacoinvasively treated STE-ACS receiving ticagrelor compared with clopidogrel in Thailand. We performed a retrospective observational study of patients with STE-ACS post streptokinase therapy followed by percutaneous coronary intervention (PCI) with coronary stent placement and receiving ticagrelor or clopidogrel as P2Y12 inhibitor treatment from January 2017 to June 2021. The primary outcomes described factors for P2Y12 inhibitor selection and evaluated safety outcomes with inverse probability weight (IPW) adjustment. The secondary outcome was a composite of all-cause death, myocardial infarction and stroke. The median time from streptokinase therapy to initiating ticagrelor in the switch group was 25.7 (IQR, 1.9-4.4) hours. The factors related to switching from clopidogrel to ticagrelor included young age, history of coronary artery disease (CAD), dose of streptokinase and use of intravascular imaging. Any bleeding events occurred among 83 patients (41.71%) in the switch group and 83 patients (41.09%) in the no switch group (adjusted HR 1.04, 95% CI 0.75-1.44; p = 0.826). The composite of efficacy outcomes occurred in 6 patients in the switch group (3.02%) and 12 patients (5.94%) in the no switch group (adjusted HR 0.57, 95% CI 0.21-1.57; p = 0.279). Conclusion: In real practice, ticagrelor switching among patients with STE-ACS post streptokinase therapy did not differ regarding safety outcomes and composite of efficacy outcomes compared with clopidogrel.