Subcutaneous Unfractionated Heparin for Treatment of Venous Thromboembolism in End-Stage Renal Disease

Abstract

Objective:

To report 3 cases of venous thromboembolism (VTE) in patients with end-stage renal disease (ESRD) treated with subcutaneous unfractionated heparin (UFH) bridged with warfarin.

Case Summaries:

Three patients with ESRD were successfully treated for VTE with unmonitored, fixed-dose subcutaneous UFH every 12 hours and doseadjusted warfarin. The first patient was initiated on continuous infusion UFH for deep-vein thrombosis, but due to poor vascular access, nurses were unable to consistently measure anti-Xa levels. Therefore, subcutaneous UFH 17,500 units (~245 units/kg/dose) every 12 hours was initiated. Oral warfarin 5 mg/day was started the following day. The patient received 4 days of inpatient subcutaneous UFH and then was discharged to complete the bridge as an outpatient. The second patient received subcutaneous UFH 10,000 units (~244 units/kg/dose) every 12 hours and oral warfarin 2.5 mg/day to treat a nonocclusive thrombus along her right femoral vein hemodialysis catheter. The patient received 1 day of inpatient subcutaneous UFH treatment prior to discharge and continued bridge therapy with warfarin as an outpatient. The third patient was initiated on subcutaneous UFH 20,000 units (~223 units/kg/dose) every 12 hours and oral warfarin 7.5 mg/day due to a subtherapeutic INR (1.50) 5 days after receiving fresh frozen plasma to reduce her therapeutic INR for a procedure. The patient received 2 doses of subcutaneous UFH as an inpatient before treatment was discontinued because her INR was therapeutic at 2.3.

Discussion:

Subcutaneous UFH has been used to treat VTE since the early 1980s; however, with the advent of low-molecular-weight heparin (LMWH), subcutaneous UFH use diminished. Several studies comparing the use of subcutaneous UFH to both continuous infusion UFH and LMWH concluded that subcutaneous UFH is a safe and efficacious alternative. The 2008 Chest Guidelines for Antithrombotic Therapy for Venous Thromboembolic Disease support the use of subcutaneous UFH for the treatment of VTE with a Grade 1A recommendation and provide a Grade 2C recommendation for use of UFH over LMWH for patients with VTE and severe renal failure.

Conclusions:

Safe and convenient treatment options for VTE in patients with ESRD are limited. Fixed-dose, unmonitored subcutaneous UFH as a bridge to warfarin therapy is an effective option in patients with ESRD and those with financial restrictions. The pharmacist plays a key role in identifying patients for whom subcutaneous UFH treatment may be a viable alternative, recommending an appropriate dosing regimen, and educating health-care professionals and patients about safe use.