Efficacious and Safe Use of Recombinant Activated Factor VII (rFVIIa) in Patients with Enoxaparin (ENOX)-Induced Bleeding and Pre-Existing Hypercoagulable States.

Introduction: rFVIIa has been touted as a pancoagulant to reverse untoward hemorrhage in various clinical situations. We describe 3 hypercoagulable patients with enox-induced bleeding treated successfully and safely with rFVIIa.

Case Summaries: Patient 1, a 58 year old female, received enox 60mg SQ q12 h for a left femoral DVT. On day 2, a bleeding right femoral pseudoaneurysm was detected. On day 3, the patient’s hematocrit fell from 37.5% to 22%, as swelling and pain ensued in the right thigh 4h after receiving her AM dose of enox. The concurrent PT, INR and aPTT were 18.1, 1.72 and 34.2 sec respectively. rFVIIa (20μg/kg) was administered intravenously with rapid cessation of bleeding. Patient 2, a 42 year old male, with a history of SLE, antiphospholipid antibody syndrome, and a distant history of a distal DVT was admitted for acute renal failure (creatinine of 4.2) secondary to lupus nephritis. One day after a kidney biopsy, the patient was placed on coumadin 5mg and continuous infusion of unfractionated heparin which was then changed to enox 70 mg SQ q 12. Both coumadin and enox were held after 4 d, once his PT, INR and aPTT reached 30, 3.97 and 56.2 sec respectively. The next day, a CT scan to evaluate a new abdominal pain revealed a large bleed at the kidney biopsy site. Despite transfusions of 6 bags of red blood cells, 4 bags of fresh frozen plasma, and 10mg of SQ vitamin K₁, his hematocrit dropped to 19% and his PT, INR, and aPTT remained elevated at 28, 3.49, and 60.8 sec respectively. Thromboembolization was achieved to terminate bleeding from 2 of his 3 renal biopsy sites, the last of which was technically inaccessible. rFVIIa (30μg/kg) was administered as an intravenous bolus with immediate cessation of active bleeding. The next day, the antifactor Xa level was 0.12 anti-Xa U/ml and the PT, INR, and aPTT were 13.7, 1.09 and 45.1 sec, respectively and remained at these levels for the next 4 days. Patient 3, a 56 year old female with a prior history of multiple PEs and proximal DVTs due to protein S deficiency, was admitted for total knee arthroplasty. Admission labs were all within normal limits. Enox 80mg sq was initiated 24 h post-operatively for DVT prophylaxis. Four h later, brisk bleeding developed acutely from the surgical site. The simultaneous antifactor Xa level was 0.49 anti-Xa U/ml. rFVIIa (20μg/kg) was administered as an intravenous bolus and bleeding from the JP drain ceased instantly. All 3 patients stabilized within hours following administration of rFVIIa for their acute bleeding events; all required multiple transfusions of FFP and packed RBCs before rFVIIa; and all resumed anticoagulation without further bleeding.

Discussion: Many clinicians fear that the rare untoward hemorrhage associated with any low molecular weight heparin (LMWH) preparation cannot be efficiently or rapidly reversed as there is no specific or reliable antidote. rFVIIa concentrate has reversed the anti-Xa properties of LMWH in ex vivo plasma-spiking experimental models but experience with use of rFVIIa to reverse LMWH-induced bleeding in vivo is lacking.

Conclusion: This report suggests that rFVIIa administered in low doses (20–30μg/kg) reverses clinically significant LMWH-induced bleeding complications effectively, rapidly, and safely and should be considered as an adjunct in the treatment of LMWH-induced bleeding in patients with either hypercoagulable conditions or acute VTE. Clinical trials are needed to confirm the effectiveness of rFVIIa in this clinical scenario.