Objective To compared the prognosis of patients taking two different antiplatelet drugs, aspirin or clopidogrel 1 year after percutaneous coronary intervention (PCI), and to analyzed the causes of differences.

Methods The clinical data of 168 patients underwent dual antiplatelet therapy for 1 year after implanted drug-coated stents from August to December 2017 were retrospectively analyzed, the patients were divided into the aspirin group (100 mg/d, N=85) and clopidogrel group (75 mg/d, N=83), according to medicine they took 1 year after dual antiplatelet therapy. Then major adverse cardiovascular events (MACEs) and bleeding complications were observed in the two groups for 18 months.

Results There were no statistically significant differences between the two groups in cardiovascular related death, recurrent angina pectoris, stent restenosis, and other endpoint events, and no serious bleeding events occurred in either group. The incidence of mild to moderate bleeding events in the aspirin group was significantly higher than that in the clopidogrel group (16.5% vs 4.8%, P=0.015), which was mainly related to the increase of gastric bleeding events in the aspirin group (8.2% vs 1.2%, P=0.032). Kaplan-Meier survival curve results further confirmed that there was no difference in the incidence of MACE events between the two groups during follow-up (log rank=0.014, P=0.905), but the incidence of mild and moderate bleeding events in the clopidogrel group was significantly lower than that in the aspirin group (log rank=5.986, P=0.014). The proportion of women (61.1% vs 34.0%, P=0.024) and age (71.89±8.37 vs64.75±9.02, P=0.002) in patients with bleeding events were significantly higher than those without bleeding. Logistic regression analysis showed that age (Exp (B)=4.771, 95%CI 1.313-17.344, P=0.018) and gender (Exp (B)=0.361, 95%CI 0.129-1.009, P=0.049) were independent risk factors for the bleeding events.

Conclusions Patients singly taking aspirin or clopidogrel have similar long-term benefits 1 year after PCI, but the risk of mild to moderate bleeding is significantly reduced in patients taking clopidogrel alone, and 75 mg/d clopidogrel is suitable for elderly female patients 1 year after PCI.