Variability in contemporary heparin prescription and activated clotting time monitoring during percutaneous coronary intervention: call for up-to-date evidence-based guidelines

Background: Unfractionated heparin (UFH) is the preferred anticoagulant agent in percutaneous coronary intervention (PCI) procedures for minimising the risk of thrombotic complications. Because of the narrow therapeutic range of UFH, some society guidelines have advocated the use of the activated clotting time (ACT) test to monitor anticoagulation intensity during PCI to reduce thrombotic and bleeding complications. We aimed to assess the current practice of UFH prescription and its monitoring in Australia and New Zealand (ANZ). Method: We conducted an anonymous voluntary cross-sectional survey of interventional cardiologists (ICs) who were members of the Cardiac Society of Australia and New Zealand in 2022. The survey included 10 questions pertaining to the current practice of anticoagulation during PCI. Results: Of 430 ICs surveyed, 148 responded (response rate, 34.4%). Most ICs (84.4%) prescribed 70–100 IU/kg of UFH for PCI. Over half of ICs (58.7%) routinely measured ACT during PCI, whereas only 22.2% routinely measured ACT after PCI to guide additional UFH prescription. Among ICs who prescribed additional UFH, approximately half (48%) aimed for ACT ≥250 seconds. Factors that influenced post-PCI UFH prescription included vascular access site and concomitant antiplatelet or anticoagulant therapy. Conclusions: The contemporary practice of UFH prescription during PCI and ACT monitoring in ANZ is variable and based on outdated evidence preceding current drug-eluting stents, antiplatelet therapies, and radial-first practice. Current society guideline recommendations lack clarity and agreement, reflecting the quality of the available evidence. Up-to-date clinical trials evaluating UFH prescription and ACT monitoring are needed to optimise clinical outcomes in contemporary PCI procedures.