Impact of intravascular imaging guidance on the effects of aspirin-free strategy for percutaneous coronary intervention for acute coronary syndrome: a post-hoc analysis from the STOPDAPT-3 trial
K Takabayashi, H Watanabe, M Natsuaki, T Morimoto, T Yamamoto, T Ichinohe, D Takagi, M Miho, T Kato, H Nakai, H Shimada, K Takenaka, H Takenaka, Y Nakagawa, T KimuraAbstract
Background
Previous studies have demonstrated that intravascular imaging during percutaneous coronary intervention (PCI) improves clinical outcomes after the procedure. However, it remains uncertain whether intravascular imaging modifies the effects of an aspirin-free strategy at the time of PCI in patients with acute coronary syndrome (ACS).
Purpose
To evaluate the interaction between the intravascular imaging guidance and the relative effects of an aspirin-free strategy compared with dual antiplatelet therapy (DAPT) in PCI for ACS patients.
Methods
This is a post-hoc subgroup analysis of the STOPDAPT-3 (Short and Optimal Duration of Dual Antiplatelet Therapy-3) trial, a multicenter, open-label, randomized controlled study conducted in Japan. The participants were randomized to either prasugrel monotherapy without aspirin (no-aspirin group) or the DAPT group just before PCI. ACS patients enrolled in STOPDAPT-3 were stratified by intravascular imaging use (intravascular ultrasound or optical coherence tomography) during index PCI. The two coprimary endpoints were a bleeding endpoint (Bleeding Academic Research Consortium [BARC] type 3 or 5) and a cardiovascular endpoint, comprising death, myocardial infarction, definite stent thrombosis, or ischemic stroke at 30 days.
Results
Among 4,476 ACS patients, intravascular imaging was used in 4,111 patients (91.8%), whereas 365 (8.2%) underwent PCI guided by angiography alone. In the non-imaging subgroup, the 30-day cumulative incidence rates of the coprimary bleeding endpoint were 7.3% in the no-aspirin group and 6.4% in the DAPT group (hazard ratio [HR] 1.16, 95% confidence interval [CI] 0.52–2.54), while in the imaging subgroup, the rates were 4.7% and 5.2%, respectively (HR 0.90, 95% CI 0.68–1.18), with no significant interaction (P interaction=0.56). The 30-day cumulative incidence rates of the coprimary cardiovascular endpoint were 5.2% and 3.5% (HR 1.51, 95% CI 0.55–4.17) in the non-imaging subgroup, and 4.7% and 3.9% in the imaging subgroup (HR 1.20, 95% CI 0.89–1.61), with no significant interaction (P interaction=0.66).
Conclusions
Among patients with ACS undergoing PCI, the clinical effects of an aspirin-free antiplatelet strategy compared with standard DAPT were not significantly affected by intravascular imaging guidance. These findings reinforce the conceptual independence of pharmacologic and procedural optimization strategies and provide important guidance for the global application of contemporary antiplatelet therapy, particularly in regions with limited routine use of intravascular imaging.