Efficacy and safety of switching from ticagrelor to clopidogrel during the early and late phase in acute coronary syndrome patients after percutaneous coronary intervention.

In patients with acute coronary syndrome (ACS), treatment using ticagrelor demonstrated significant ischemic benefits over clopidogrel; however, it was associated with increased bleeding complications leading to frequent de-escalation to clopidogrel. The objective of the present study was to investigate the efficacy and safety of de-escalation in early and late phase after percutaneous coronary intervention (PCI). We performed a retrospective study of 4678 ACS patients from March 2016 to April 2017 who initially received ticagrelor then de-escalated to clopidogrel and categorized them into Group 1: early phase (1-30 days) and Group 2: late phase (>30 days-1 year) switching groups. The primary efficacy endpoints included cardiovascular death, definite/probable stent thrombosis, myocardial infarction, unplanned revascularization, and stroke. The safety endpoint was Bleeding Academic Research Consortium classification 3 or 5 bleeding events within 1 year after PCI. The incidence of switching occurred in 1019 patients; 380 (37.3%) in Group 1 (median 14 days, interquartile range 4-30 days) versus 639 (62.7%) in Group 2 (median 180 days, interquartile range 90-270 days). The ischemic endpoints occurred in 53 (13.9%) patients in Group 1 versus 35 (5.4%) in Group 2 (HR 1.93,95%CI 1.22-3.08, p < .0001). There were no significant differences of major bleeding events (HR 0.91; 95%CI, 0.58-1.43, p = .90) seen between the groups. The main cause for switching between the two groups was due to BARC 1 or 2 bleeding types. Early de-escalation from ticagrelor to clopidogrel during the initial 30 days after ACS was associated with higher risk of ischemic events when compared with switching beyond 30 days.