Peri‐operative Anticoagulant Effects of Heparinization for Carotid Endarterectomy

Abstract

The question of whether or not to reverse heparin following carotid endarterectomy is a topic of debate. The potential reduction of the risk of thrombosis at the endarterectomy site with non‐reversal has to be measured against a potential increase in the risk of wound haematoma. This study prospectively followed activated clotting time (ACT) of 42 consecutive patients undergoing carotid endarterectomy. A standard heparin dose of 100 units/kg was used, and heparin reversal was employed only if the wound appeared excessively haemorrhagic at the procedure's completion. Heparin was reversed in 11 patients. Following heparin administration, ACT increased to a mean 2.72 ± 0.09 times baseline (range 1.84–4.07), and fell with time, until at 3 h after heparin administration mean ACT in the non‐reversed patients was 1.48 ± 0.03 times baseline (range 1.1–2.03). There was one postoperative neurological event (2%), a contralateral hemisphere stroke. No patient developed a frank wound haematoma requiring evacuation, although three patients (7% of the total study group, 9% of patients not receiving heparin reversal) developed neck swelling and symptoms of airway compromise, and were intubated. Measurements of ACT suggest that a heparin dose of 100 units/kg achieves an adequate anticoagulant level in the operative and early postoperative phase, when thrombosis is most likely to occur, and is not associated with an increased risk of wound haematoma. If heparin is to be selectively reversed in patients felt to be at high risk of postoperative haematoma, the decision should be based on an objective measurement such as ACT, and not the surgeon's impression of wound haemostasis.

Safety and Efficacy of Fixed-dose Heparin in Carotid Endarterectomy

“…ACT monitoring has been shown to be simple and inexpensive and to correlate reliably with both serum heparin concentration and partial thromboplastin time (11,15). Furthermore, several studies have suggested that the ACT value is more effective than partial thromboplastin time for monitoring the level of intraoperative anticoagulation (9,22). Nonetheless, whereas therapeutic ACT values have been established for cardiac surgery, appropriate anticoagulation for patients undergoing carotid endarterectomy (CEA) is not entirely clear (2,21).…”

Safety and efficacy of intravenous enoxaparin for carotid endarterectomy: A prospective randomized pilot trial

“…It is also not clear which dose is optimal because 70 up to 100 IU/kg are used. 22,23 Most important, for these regimens, antagonization with protamine was recommended, which is a potential cause for significant morbidity. 24 In this respect, however, UFH is superior to LMWH because the at least partial inability to reverse the effect of enoxaparin is frequently regarded as a serious limitation for its use in vascular surgery.…”

No Concluding Evidence on Optimal Activated Clotting Time for Non-cardiac Arterial Procedures

“…23,25e28,36 High ACTs after heparin administration seem to be associated with haematoma formation. 24 In contrast, heparin reversal could increase the risk of periprocedural and immediate post-procedural thrombus formation. 26,27 The number of haemorrhagic and thromboembolic complications in all studies was too small to allow a comparison between the heparin and no heparin reversal groups.…”