Long-term anticoagulation with warfarin is required for patients with left ventricular assist devices (LVADs). There is limited data of time in therapeutic range (TTR) in this population, with reports of 31% to 52%. We sought to evaluate the TTR for an institution-based, pharmacist-managed anticoagulation clinic in the LVAD population.

We retrospectively reviewed adults with an LVAD managed in the anticoagulation clinic from September 1, 2015 through August 31, 2016. Patient characteristics and adverse outcomes including bleeding events (BE) and thrombotic events (TE) as defined by INTERMACS criteria were studied. Included patients were on outpatient warfarin therapy for at least 90 days regardless of LVAD implant date and managed by a pharmacist-managed anticoagulation clinic via a collaborative practice agreement with LVAD providers. The pharmacists were not located within the LVAD clinic, but received appropriate training. TTR was calculated by the Rosendaal method, which assumes a linear relationship between consecutive INR measurements while taking into account changes in the target INR range.

Our study population consisted of 52 patients (mean age 57 years, 71% males, 61% bridge to transplant, 83% received HeartMate II device) with a total of 2143 INRs. The median TTR was 63.8% (IQR = 53.5-74.4%). During the study period 17 patients had 30 BE and 3 patients had 3 TE. No significant difference was identified in TTR between patients with and without thrombotic events (TE 47%±19% vs no TE 64%±15, p=0.1). Patients with a bleeding event did have a significantly lower TTR compared to patients with no bleeding event (BE 57%±16 vs no BE 67%±15, p=0.038). In a proportional hazards (Cox) model with adjustment for relevant covariates, TTR was not associated with BE or TE.

Management of anticoagulation in LVAD patients by an institution-based, pharmacist-managed anticoagulation clinic is effective with achieved TTR similar to and numerically higher than previous studies. This is a service that could be considered at other LVAD centers to expand productivity for LVAD team members.

CITATION INFORMATION: Bibb T., Halder L., McDanel D., Briasoulis A., Alvarez P., Horner K., Bhama J., Larson S. Institution-Based, Pharmacist-Managed Anticoagulation in Patients with a Left Ventricular Assist Device Am J Transplant. 2017;17 (suppl 3).

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