Should heparin be reversed after carotid endarterectomy? A randomised prospective trial

Objective: To investigate whether heparin reversal after carotid endarterectomy reduces the incidence of haemorrhagic complications. Design: A randomised prospective trial. Methods: Sixty-four patients randomised to reversal of heparin or no reversal, of whom 31 received protamine titrated to the residual circulating heparin at closure of arteriotomy. Measurements included serial activated clotting times (ACTs), wound drainage, neck swelling using duplex Doppler imaging to measure the depth from skin to carotid bifurcation, and the recording of all complications. Results: Wound drainage volumes were significantly reduced by protamine reversal (68.5 ml compared to 35 ml, p<0.0001), but neck swelling was not (72 mm compared to 70 mm, p=0.77). Two patients who were not reversed developed neck haematomas requiring evacuation. More importantly, two patients receiving protamine, thrombosed the operated internal carotid artery (ICA) postoperatively and died despite urgent thrombectomy. A further patient who was not randomised in this study who received protamine also developed ICA thrombosis within the same 3 month period. Conclusions: Reversing heparin with protamine reduces postoperative wound drainage after carotid surgery but may predispose to ICA thrombosis and stroke. This is in keeping with a previous retrospective study published during our trial.(7)