Frequency and Reasons of Dual Antiplatelet Therapy Discontinuation and Switching of P2Y12 Inhibitors in Patients with Acute Coronary Syndrome Treated with Stent Implantation

Background: Incidence and reasons of dual antiplatelet therapy (DAPT) discontinuation and switching between P2Y12 inhibitors in acute coronary syndrome (ACS) patients treated with a stent have been poorly studied. Methods and Results: In a prospective single-center study, 283 consecutive patients presenting with ACS were treated with stent implantation between July 2015 and January 2016. Follow-up was achieved at 12 months in 273 patients using the electronic patient file and telephone interview. Switching from clopidogrel to a new antiplatelet agent (ticagrelor or prasugrel) or vice versa occurred in 60 (21.2%) patients. The most frequent reasons for switching were medical decisions not associated with bleeding events and concomitant use of chronic oral anticoagulation. Among the patients with a 1-year follow-up, 42 (15.4%) prematurely discontinued DAPT; 25 of them did so due to the need for an invasive procedure. DAPT premature discontinuation was not significantly associated with an increased 1-year risk of cardiovascular death or serious cardiac ischemic events (HR 2.08 [CI 95%: 0.88–4.94, p = 0.099]). Conclusions: DAPT discontinuation and switching between P2Y12 inhibitors are not uncommon in patients with ACS treated with a stent. The most frequent reasons were the need for an invasive procedure and medical decisions.