(1025) Incidence of Cerebrovascular and Bleeding Events in a Real-world Cohort of Patients with Mechanical Aortic On-x Valves Managed with Warfarin at INR Goals 1.5-2.0 and 2.0-3.0

Objectives: The PROACT Trial found that patients with a mechanical aortic On-X valve managed at international normalized ratio (INR) goals of 1.5-2.0 or 2.0-3.0 had similar incidences of thrombotic events, with a lower incidence of bleeding events in the INR 1.5-2.0 group. As a result, the ACC/AHA guidelines recommend warfarin with an INR goal of 2.0-3.0 for 3 months following placement of a mechanical aortic On-X valve, followed by a reduced INR goal of 1.5-2.0 (with concomitant aspirin) if there are no other indications for anticoagulation. The objective of this analysis was to evaluate the real-world incidence of cerebrovascular and bleeding events in patients with mechanical aortic On-X valves on warfarin managed at INR goals 1.5-2.0 and 2.0-3.0.

Methods: This was a single-center retrospective chart review of all patients with mechanical On-X valves on warfarin who were managed by a centralized anticoagulation management service through July 2023. Patient charts were reviewed for cerebrovascular events including ischemic stroke and transient ischemic attack (TIA), as well as for any documented bleeding events. Other data collected included baseline patient characteristics, date of event in relation to valve placement, INR at time of event, INR goal, and concomitant aspirin.

Results: Of the 111 patients included, 52 (46.8%) were managed with an INR goal of 1.5-2.0, 57 (51.4%) were managed with an INR goal of 2.0-3.0, and 2 (1.8%) were managed with an alternative INR goal of 1.8-2.3.

Cerebrovascular and/or bleeding events occurred in 26 (23.4%) patients. At the time of the event, 6 (23.1%) were managed with an INR goal of 1.5-2.0 and 20 (76.9%) with an INR goal of 2.0-3.0. There were no events in the alternative INR group.

Among patients with an INR goal of 1.5-2.0, 4 (7.7%) had a cerebrovascular event and 3 (5.8%) had a bleeding event. Among patients with an INR goal of 2.0-3.0, 13 (22.8%) had a cerebrovascular event and 11 (19.3%) had a bleeding event. In this cohort, 6 (30%) were also anticoagulation for atrial fibrillation.

For patients with INR goal 1.5-2.0 who experienced a cerebrovascular event, 3 (50%) had their INR goal changed in result.

Of patients with any event, low-dose aspirin was co-prescribed in 4 (66.7%) with an INR goal of 1.5-2.0, 12 (60%) with an INR goal of 2.0-3.0, and 0 (0%) with the alternative INR goals.

Conclusions: In a real-world cohort of patients with mechanical aortic On-X valves managed with an INR goal 1.5-2.0, the incidence of cerebrovascular and bleeding events respectively was similar compared with previously published data. Meanwhile, the incidence of cerebrovascular events in patients managed with an INR goal of 2.0-3.0 was higher and bleeding events was similar compared with previously published data.