Antiplatelet therapy and prognosis at the onset of stent thrombosis

Abstract Background/Introduction Antiplatelet therapy is the standard therapy after stent implantation. Stent thrombosis (ST) has dramatically decreased by appropriate antiplatelet therapy and advancement in stent technology, but remains a life-threatening event if it occurs. Some patients develop ST even under intensive antiplatelet therapy (dual antiplatelet therapy; DAPT). The association of prognosis of ST and antiplatelet therapy at the onset of ST is unclear. Purpose We aimed to investigate the association of prognosis and antiplatelet therapy at the onset of ST. Methods We used the database of Long-term Outcomes following Occurrence of Stent Thrombosis registry, a multicenter, retrospective, observational study (Long ST registry). Definite ST cases from January 2008 to December 2017 were enrolled, and long-term clinical outcomes were investigated. Results A total of 187 patients (male: 86.1%, median age at the time of ST: 69.0) were eligible. Ninety patients were under DAPT at the onset of ST (DAPT group), whereas 97 patients were under single antiplatelet therapy or no antiplatelet therapy (non-DAPT group). The median follow-up duration was 1054.0 (inter-quartile range, 239.5 – 1850.0) days. Findings of intravascular ultra sounds at the time of ST were similar between two groups. Patients in DAPT group were independently associated with higher incidence of major adverse cardiac events (MACE: a composite of cardiovascular death, nonfatal myocardial infarction, and target lesion revascularization) than in non-DAPT group (adjusted hazard ratio: 2.36, 95% confidence interval [1.27 - 4.34], P value = 0.006). Conclusion Patients who developed ST under DAPT were independently associated with a higher incidence of MACE than patients under single or no antiplatelet therapy.