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

The current guidelines for acute coronary syndrome (ACS) discourage the use of anticoagulation after percutaneous coronary intervention (PCI) without specific indications, although the recommendation is not well supported by evidence. In this post hoc analysis of the ShorT and OPtimal Duration of Dual AntiPlatelet Therapy-3 (STOPDAPT-3) trial, 30-day outcomes were compared between the 2 groups with and without post-PCI heparin administration among patients with ACS who did not receive mechanical support devices. The co-primary end points were the bleeding end point, defined as the Bleeding Academic Research Consortium type 3 or 5 bleeding, and the cardiovascular end point, defined as a composite of cardiovascular death, myocardial infarction, definite stent thrombosis, or ischemic stroke. Among 4,088 patients with ACS, 2,339 patients (57.2%) received post-PCI heparin. The proportion of patients receiving post-PCI heparin was higher among those with ST-elevation myocardial infarction compared with others (72.3% and 38.8%, p <0.001), and among patients with intraprocedural adverse angiographic findings compared with those without (67.6% and 47.5%, p <0.001). Post-PCI heparin compared with no post-PCI heparin was associated with a significantly increased risk of the bleeding end point (4.75% and 2.52%, adjusted hazard ratio 1.69, 95% confidence interval 1.15 to 2.46, p = 0.007) and a numerically increased risk of the cardiovascular end point (3.16% and 1.72%, adjusted hazard ratio 1.56, 95% confidence interval 0.98 to 2.46, p = 0.06). Higher hourly dose or total doses of heparin were also associated with higher incidence of both bleeding and cardiovascular events within 30 days. In conclusion, post-PCI anticoagulation with unfractionated heparin was frequently implemented in patients with ACS. Post-PCI heparin use was associated with harm in terms of increased bleeding without the benefit of reducing cardiovascular events. Trial identifier: STOPDAPT-3 ClinicalTrials.gov number, NCT04609111