Evaluation of argatroban to warfarin transition process in heparin-induced thrombocytopenia

The argatroban to warfarin transition in heparin-induced thrombocytopenia (HIT) is complicated as argatroban falsely elevates the international normalized ratio. The evaluation aims were to assess compliance with institutional guidelines for this transition and transition success. This was a retrospective, single-system, observational cohort study of confirmed HIT patients receiving argatroban with the goal of warfarin transition between January-2019 and June-2024. Data collection included demographics, anticoagulant dosing, venous and arterial thromboses, major and clinically relevant non-major bleeding (CRNMB), and laboratory data. The primary endpoint was compliance with all eight steps of institutional guidelines. Secondary endpoints included individual compliance steps and transition success (defined as completion within seven days and absence of bleeding, thrombosis, non-therapeutic international normalized ratios (INRs) and argatroban restarts). A Fisher's Exact test assessed the relationship between compliance and outcomes, significance at p < 0.05. Thirty-two argatroban to warfarin courses were evaluated in 29 patients. Compliance occurred in 10/32 (31.3%) of courses. Non-compliance was often due to failure to perform a two-step argatroban discontinuation process with doses > 2 mcg/kg/min (6/14, 42.9%). Transition success occurred in 50% (16/32) of courses. An extended bridge (argatroban and warfarin co-therapy) beyond seven days was the most common reason for failure in 29% (9/31). Bleeding (major and CRNMB) and thrombosis occurred in 18.8% and 6.3% of courses, respectively. There was no relationship between compliance and outcomes. The process for transitioning HIT patients from argatroban to warfarin is complex. The low rate of compliance and transition success highlights the challenging nature of this transition.