Purpose: Dual antiplatelet therapy with aspirin and a P2Y12 inhibitor is recommended for patients with acute coronary syndrome and after percutaneous coronary intervention with stenting in stable coronary artery disease to help prevent further thromboembolic events. However, there is limited guidance on appropriate strategies for switching between oral P2Y12 inhibitors. The aim of this study was to evaluate safety of switching modalities at our institution and compare them to the recently published expert consensus recommendations. 

Methods: This was a retrospective, descriptive analysis of patients admitted to Brigham and Women’s Hospital from January 2015 to December 2018. Patients were included if they were at least 18 years of age and had documented administrations of two or more oral P2Y12 inhibitors during the same admission. The major safety endpoint was incidence of major adverse cardiac events (MACE) (cardiovascular death, myocardial infarction, stroke, and non-coronary artery bypass grafting (CABG)-related bleeding) at seven days or until hospital discharge. Minor endpoints included the incidence of in-stent thrombosis, number of patients who received appropriate loading doses (LD) before and after the recently published recommendations, and documented reason for switching between agents. 

Results: There were 253 patients included in the final analysis. Of these, 83 patients were on clopidogrel as the first agent prior to switching, 9 patients were on prasugrel, and 161 were on ticagrelor. There was no incidence of the primary safety endpoint observed in any group. However, the number of patients who received a LD when switching between oral P2Y12 inhibitors increased from 80.0% to 87.0% after publication of the expert consensus paper. The most common reasons for switching from one agent to another were cost/insurance coverage (19.0%), need for triple therapy (16.0%), and bleeding risk (11.0%). 

Conclusion: Different switching modalities were not associated with an increase in MACE at our institution; however, larger randomized controlled trials are warranted.