Use of argatroban as a procedural and bridging anticoagulant in a patient undergoing carotid endarterectomy with concomitant atrial fibrillation.

Objective: To describe the use of argatroban as a procedural and bridging anticoagulant in a patient with a previous history of heparin allergy and atrial fibrillation undergoing carotid endarterectomy.

Case Summary: A 78-year-old female with a history of heparin-induced thrombocytopenia (HIT) and multiple medical comorbidities, including atrial fibrillation requiring chronic anticoagulation with warfarin, was found to have greater than 70% stenosis of her left carotid artery by standard duplex imaging. Her warfarin therapy was discontinued as an outpatient approximately 48 hours prior to an elective left carotid endarterectomy and she was started on argatroban 2 μg/kg/min for bridging therapy. The endarterectomy was successfully performed while the patient was maintained on a continuous argatroban infusion. The dose was adjusted by 0.25-μg/kg/min intervals to achieve and maintain an activated clotting time of greater than 200 seconds during the procedure. Her postoperative course was unremarkable and she was transitioned back to warfarin and subsequently discharged home.

Discussion: HIT poses a challenge for patients in need of vascular surgery. Optimally, one would postpone any surgical intervention until the heparin antibodies are cleared from circulation, which on average takes about 100 days. In theory, it is safe to reexpose these patients to heparin products upon clearance of the antibody; however, there is scant literature available to show its safety. Current guidelines recommend limiting heparin exposure in any patients with a history of HIT, but the optimal alternative anticoagulant in this setting is unclear. There are several direct thrombin inhibitors available, but argatroban seemed to be a logical choice for our patient, especially in the setting of renal insufficiency, given its favorable pharmacokinetics and ease of monitoring with readily available coagulation tests. To our knowledge, this is the second reported case of the systemic use of argatroban in carotid endarterectomy in a patient with a previous history of HIT.

Conclusions: Argatroban may be an effective anticoagulant during carotid endarterectomy in patients with underlying chronic renal disease and a history of HIT. Additional research is needed to determine the ideal anticoagulant in vascular surgery when heparin cannot be utilized.