Optimal Duration of Dual Antiplatelet Therapy After Carotid Artery Stenting: A Nationwide Cohort Study

Carotid artery stenting (CAS) is an alternative treatment for patients with carotid artery stenosis who are not eligible for carotid endarterectomy. Dual antiplatelet therapy (DAPT) after CAS aims to prevent ischemic stroke. However, its optimal duration remains unclear. We aimed to determine the optimal duration of DAPT by identifying the differences in clinical events that occur depending on the DAPT maintenance period. Data were obtained from the nationwide database of the Korean Health Insurance Review and Assessment Service between 2007 and 2019. Patients who received CAS, as identified by procedure codes, were divided into 2 groups according to the duration of DAPT (aspirin and clopidogrel): those who maintained DAPT for at least 90 days but for <6 months (short-DAPT group) and those who maintained it for longer (long-DAPT group). The primary outcome was a composite of ischemic stroke, gastrointestinal bleeding, and intracranial hemorrhage within 12 months of switching to single antiplatelet therapy. Statistical analyses used inverse probability of treatment weighting to balance baseline characteristics, with Cox regression and Fine and Gray competing risk models used to assess outcomes. Of the 12 034 patients who underwent CAS, 2529 and 9505 were assigned to the short-DAPT and long-DAPT groups, respectively. In the short-DAPT group, ischemic stroke, gastrointestinal bleeding, and intracranial hemorrhage occurred in 41 (1.6%), 22 (0.9%), and 4 (0.2%) patients, respectively. In the long-DAPT group, ischemic stroke, gastrointestinal bleeding, and intracranial hemorrhage occurred in 108 (1.1%), 87 (0.9%), and 4 (0.04%) patients, respectively. The primary outcome did not differ significantly between the groups (2.5% versus 2.1%; adjusted hazard ratio of long-DAPT to short-DAPT, 0.869 [95% CI, 0.652-1.158]; P=0.337). Short-duration DAPT can be recommended, as it does not differ from long-duration DAPT in terms of clinical efficacy and adverse events after CAS.