Use of low molecular weight heparin in patients with heparin-induced thrombocytopenia undergoing carotid endarterectomy

CAROTID endarterectomy (CEA) is a common vascular surgical procedure for patients with severe carotid stenosis. Heparin therapy, widely used during CEA, is not without risks and sometimes may be associated with a decrease in platelet count or thrombosis, a condition called heparin-induced thrombocytopenia (HIT)2.This condition is believed to be immunology mediated an involves the formation of heparin-dependent platelet antibodies (HDPS)3 that recognize a complex of heparin and platelet factor 4. The estimated prevalence of HDPA in patients receiving heparin is 7.8%. In patients with HIT who are candidates for CEA, a substitute for unfractionated heparin (UFH) should be used. Low molecular weight heparins (LMWHs) have a favorably high anti-factor Xa-to-anti-factor IIa activity ratio, which implies an improved antithrombotic potential with fewer bleeding side effects. The antithrombotic intravenous dose of LMWH (enoxapirin) during CEA has not been established. We report the intraoperative use (dose and monitoring) of enoxaparin (Lovenox, Rhone-Poulene Rorer Pharmaceuticals, Collegeville, PA) in three patients with documented HIT and HDPA who underwent four CEAs.