Category: Professional Posters
The purpose of this patient case is to describe the management of an obese patient on hemodialysis who is being bridged with enoxaparin and warfarin for treatment of a superior vena cava thrombus. The patient’s information was collected from the electronic medical record. The patient is a 45-year-old female admitted to the hospital for a skin graft placement after elective left upper extremity arteriovenous graft infection. The patient has a past medical history of a gastrointestinal bleed, morbid obesity, superior vena cava thrombus (diagnosed two months prior to admission), and end-stage renal disease on hemodialysis. The patient’s actual body weight is 148.8 kg, whereas her ideal body weight is 66.2 kg. During the admission, the patient was on a high dose heparin drip as a bridge therapy with warfarin due to a sub-therapeutic INR. However, the patient lost intravenous access, resulting in discontinuation of the heparin drip and a transition to enoxaparin. Pharmacy was consulted to dose enoxaparin.
Literature provides limited treatment options for subcutaneous or oral agents in a setting of a superior vena cava thrombus treatment in hemodialysis patients. Additionally, there is limited guidance on enoxaparin dosing in obese patients on hemodialysis. The pharmacist initiated the patient on enoxaparin 1mg/kg every 24 hours using an adjusted weight (99.2 kg) with Low Molecular Weight Heparin (LMWH) anti-Xa level monitoring. Per CHEST Guidelines, the therapeutic range for anticoagulation is 0.6-1 units/mL. Literature suggests that LMWH anti-Xa levels should be checked at their peak at four hours after dosing. Enoxaparin is predominately renally cleared. In a setting of renal failure, this may cause enoxaparin’s half-life to be prolonged and lead to an increased risk of bleeding. At the institution, the LMWH anti-Xa level is not done in-house. Because of the prolonged turnaround time of the lab and high risk of bleeding, the LMWH anti-Xa level was drawn four hours after the second dose. The pharmacist monitored for signs of bleeding and thrombosis regularly due to a high risk of both.
The pharmacist also managed the patient’s warfarin by adjusting the dose based on the INR daily. The medical team planned to bridge the patient for five days and until the INR was within goal of 2-3. The LMWH anti-Xa level resulted within goal at 0.6 units/mL and the same dose was continued for a total of four days. While on enoxaparin and warfarin, the pharmacist also counseled the patient on appropriate use of her anticoagulation medications as well as possible side effects. Once intravenous access was re-established, the pharmacist intervened by transitioning the patient back to a high dose heparin drip as soon as possible. The patient was successfully bridged for five days and achieved a therapeutic INR without any complications. Thus, it is the role of a pharmacist to recommend appropriate dosing and monitoring of anticoagulation agents, provide education to the patient, as well as transition the patient to a safer alternative when possible to prevent complications.