Post-PCI Anticoagulation with Unfractionated Heparin in Acute Coronary Syndrome: Insight from the STOPDAPT-3 Trial

The current guidelines for acute coronary syndrome (ACS) have discouraged the use of anticoagulation after percutaneous coronary intervention (PCI) without specific indications, although the recommendation was not well supported by evidences. As a post-hoc analysis of the STOPDAPT-3 trial, the 30-day outcomes were compared between the two groups with and without post-PCI heparin administration among ACS patients without the use of mechanical support devices. The co-primary endpoints were the bleeding endpoint defined as the Bleeding Academic Research Consortium type 3 or 5 and the cardiovascular endpoint defined as a composite of cardiovascular death, myocardial infarction, definite stent thrombosis, or ischemic stroke. Among 4088 ACS patients, 2339 patients (57.2%) received post-PCI heparin. The proportion of patients receiving post-PCI heparin was higher in ST-elevation myocardial infarction than in the others (72.3% and 38.8%, P<0.001), and in patients with intraprocedural adverse angiographic findings than in those without (67.6% and 47.5%, P<0.001). Post-PCI heparin compared to no post-PCI heparin 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). Higher hourly dose or total doses of heparin were also associated with the higher incidence of both bleeding and cardiovascular events within 30 days. In conclusion, post-PCI anticoagulation with unfractionated heparin was frequently implemented in ACS patients. Post-PCI heparin use was associated with harm in terms of bleeding without a benefit in reducing cardiovascular events.