Comparing Pharmacist‐Managed Warfarin Versus Usual Care in HeartMate 3 Patients: A Multicenter Retrospective Observational Study

BACKGROUND: Limited literature has evaluated strategies to maximize time in therapeutic range (TTR) in patients with left ventricular assist devices (LVADs) maintained on warfarin therapy. In non-LVAD populations, pharmacist-managed warfarin results in higher TTR and improved clinical outcomes. No study has evaluated the impact of pharmacist-managed outpatient warfarin exclusively in HeartMate 3 (HM3, Abbott Medical, Pleasanton, CA) LVAD patients. METHODS: This multicenter, retrospective cohort study included patients implanted with HM3 LVADs across six medical centers in the United States from January 2019 to May 2023. The study compared pharmacist-managed (RPH) warfarin therapy with usual warfarin care (UC), which was managed by any nonpharmacist clinician. The primary end point was TTR over 1 year using Rosendaal's method. RESULTS: Overall, 277 patients were included, 191 in the RPH group and 86 in the UC group. The TTR was 65.6% in the RPH group and 45.8% in the UC group (p < 0.001). This significant difference persisted after adjusting for confounding variables. There was no significant difference in thromboembolic events between groups. There was no difference in bleeding outcomes between groups when Mechanical Circulatory Support-Academic Research Consortium Type 1 bleeding was excluded (RPH 19.3% vs. UC 12.4%, p = 0.17). CONCLUSION: In patients with HM3 LVADs receiving warfarin, pharmacist-managed warfarin led to a higher TTR compared with UC.