Compared with clopidogrel monotherapy, cardiovascular and bleeding outcomes were similar with aspirin monotherapy beyond one month and up to one year after PCI in patients with acute coronary syndromes (ACS), whether or not they were at high bleeding risk (HBR) or had a STEMI or NSTE-ACS, according to results from the STOPDAPT-3 trial published June 4 in JACC: Cardiovascular Interventions.

In a physician-initiated, multicenter, open-label, adjudicator-blinded clinical trial, Yuki Obayashi, MD, et al., examined the effects of aspirin vs. clopidogrel within one year after PCI in patients with ACS in relation to their bleeding status (HBR or non-HBR) and type of ACS (STEMI or NSTE-ACS). The co-primary cardiovascular endpoint was a composite of cardiovascular death, myocardial infarction (MI), definite stent thrombosis or ischemic stroke. The co-primary bleeding endpoint was major bleeding.

The authors note that patients with HBR were older, less likely to be men, had a lower BMI and presented less often with STEMI. Additionally, patients with HBR more often had comorbidities such as prior MI, prior stroke, prior heart failure, atrial fibrillation and diabetes, among others.

Among the 4,353 patients included in the 30-day landmark analysis, 1,711 had HBR and 2,457 had STEMI. Compared with clopidogrel, the crude hazard ratios (HRs) for aspirin were not statistically significant for cardiovascular endpoints in the HBR or non-HBR groups (0.89 vs. 1.08) or in the STEMI or NSTE-ACS groups (1.01 vs. 0.81). Likewise, there were no significant between-group differences for the bleeding endpoint (HR 0.73 vs. 0.71 for HBR vs. non-HBR; HR 0.96 vs. 0.53 for STEMI vs. NSTE-ACS).

"On the basis of the precise risk stratification, further long-term follow-up studies are warranted to evaluate the effects of aspirin vs. clopidogrel in patients with ACS. Comparisons of aspirin with other P2Y12 inhibitors and comparisons among different P2Y12 inhibitors should also be explored," the authors write.

In an accompanying editorial comment, Antonio Greco, MD, PhD, writes that "The optimal duration of [dual antiplatelet therapy] and the subsequent choice of monotherapy remain subjects of debate. As such, therapeutic decisions must be guided by clinical wisdom to reflect a balance between available evidence, individual patient's characteristics, risk profiles and the unique circumstances of each case."