Low-intensity heparin infusion compared to high-intensity heparin infusion dosing in patients with mechanical mitral valves: a retrospective cohort study

Abstract: Patients with a mechanical mitral valve have an increased risk of thrombosis, and guidelines recommend a higher international normalized ratio (INR) goal for vitamin K antagonists (VKA) based anticoagulation. Guidelines provide recommendations for bridging with unfractionated heparin; however, there is no clear guidance on the heparin infusion intensity that should be utilized. This study was a retrospective, single-center, cohort study of patients aged ≥ 18 years of age or older with a mechanical mitral valve admitted from June 2019 to September 2022 who were maintained on a singular heparin infusion intensity nomogram for at least 48 hours. The patients were stratified into either a low- or high-intensity heparin infusion nomogram. The exclusion criteria included non-nomogram heparin infusions and patients within 30 days of valve implantation. The primary outcome of this study was a composite of all bleeding events (major, clinically significant non-major, and minor bleeding). The secondary outcomes included bleeding events, analyzed individually, and thrombotic events. Seven total bleeding events were observed between the two groups, with one minor bleeding event in the low-intensity group and six bleeding events in the high-intensity group. One thrombotic event occurred in the high-intensity group. No statistically significant differences were found between the primary and secondary outcomes. Future studies are necessary to guide heparin infusion intensity selection in patients with mechanical mitral valves.