Post-PCI anticoagulation with unfractionated heparin in acute coronary syndrome: insight from the STOPDAPT-3 trial

Abstract Background The guidelines recommend the post-procedural anticoagulation should be discontinued after percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS) except for the specific indications.(1) However, these guideline recommendations were not well supported by data, and therefore, post-PCI parental anticoagulation has been commonly implemented in patients with ACS in the previous studies.(2-5) Purpose To clarify the preference and clinical situations of post-PCI unfractionated heparin (UFH) in ACS patients and to explore the influence of post-PCI UFH on cardiovascular and bleeding outcomes. Methods STOPDAPT-3 trial is a randomized controlled trial to demonstrate the efficacy and safety of the aspirin-free prasugrel monotherapy strategy compared to the conventional dual antiplatelet therapy after PCI in patients with high-bleeding risk or ACS.(6) Data on periprocedural heparin use and its doses were vigorously collected. The current study population was the ACS patients enrolled in the STOPDAPT-3 without use of mechanical circulatory support devices. The two co-primary endpoints were the bleeding outcome defined as the BARC 3 or 5 criteria and the cardiovascular outcome defined as a composite of cardiovascular death, myocardial infarction, definite stent thrombosis, or ischemic stroke. Outcomes were assessed at 30 days from index PCI. Results Among 4088 ACS study patients, 2339 (57.2%) patients received post-PCI UFH. Median dose of UFH was 7.1 (IQR 6.0-8.8) units/kg/hour and the median duration was 25 (IQR 24-48) hours. As many as 57.7% of patients received 10000 units/day of heparin after PCI irrespective of body weight. STEMI patients more frequently received post-PCI UFH compared to NSTE-ACS (72.3% and 38.8%, P<0.001) and the patients with intraprocedural adverse angiographic findings such as thrombus, slow-flow, no-reflow, or final TIMI flow <=2 also more frequently received post-PCI UFH than those without (67.6% and 47.5%, P<0.001). Post-PCI UFH was associated with a significantly increased risk of bleeding endpoint (4.75% and 2.52%, adjusted HR 1.69 [95%CI 1.15-2.46], P=0.007) and a numerically increased risk of cardiovascular endpoint (3.16% and 1.72%, adjusted HR 1.56 [95%CI 0.98-2.46], P=0.06). Even in the patients with intraprocedural adverse angiographic findings, post-PCI UFH did not show a clear benefit for cardiovascular endpoint (3.15% and 1.72%, adjusted HR 1.73 [95%CI 0.88-3.41]. P=0.11). Conclusion(s) Post-PCI anticoagulation with UFH was frequently implemented in ACS patients enrolled in the latest large Japanese clinical trial. Post-PCI UFH use was associated with harm in terms of bleeding without a benefit in reducing cardiovascular events.