Intraoperative Assessment of the Technical Adequacy of Carotid Endarterectomy

Angiography

Blaisdell and colleagues were the first to recognize the potential of intraoperative testing to decrease the morbidity of carotid endarterectomy. They found a 26% incidence of technical error using completion arteriography, with most of the defects being strictures. Others have also found technical errors following carotid endarterectomy, and the rate of reoperation when completion arteriography has been used has ranged from 2.4% to 26%.

Owing to the relatively low stroke rate associated with carotid endarterectomy, it has been difficult to demonstrate that the use of intraoperative arteriography actually decreases the complication rate because of the large number of patients required to assure a statistically reliable result. An exception is the report by Scott’s group, which showed a significant difference in the stroke rate when 146 procedures in which intraoperative arteriography was not used were compared with 137 endarterectomies in which intraoperative arteriography was used. These authors found that the stroke rate was reduced from 6.8% to 3.8%, and the mortality rate was reduced from 4.8% to 1.5% when intraoperative completion arteriography was employed. However, the groups were concurrent rather than randomized.

Another potential benefit of using intraoperative arteriography is the prevention of recurrent disease. Courbier and colleagues demonstrated that defects that were seen on intraoperative arteriography and that were not corrected led to a higher than usual incidence of recurrent disease. By performing arteriography a mean of 19.2 months postoperatively, Courbier and colleagues documented disease recurrence in only 3% of internal carotid arteries that had normal intraoperative arteriographic studies. This rate was considerably less than the 28% recurrence rate of when residual defects were left uncorrected.

Intraoperative completion carotid arteriography is performed before reversing the heparin effect, so that any defect that requires correction can be repaired without the need to administer heparin to the patient again. An x-ray cassette is placed under the patient’s head and neck. The head is maintained in the turned position to allow optimal separation of the internal and external carotid arteries in the anteroposterior view. The common carotid artery is punctured with a 19-gauge needle attached to a long extension tubing and a 25-mL syringe. It is most important to be sure that no air bubbles or other debris are present in the line. Just before injection, the common carotid artery is clamped as far proximal as the wound edge allows. The surgeon, standing behind a lead shield, injects 12 mL of full-strength contrast medium, and the film is exposed. The common carotid artery clamp is then removed. The needle is usually left in place until a satisfactory film has been obtained. A figure-of-eight suture is placed at the needle base, and the needle is removed as the suture is tied. Numerous variations of the technique have been described, most of which give satisfactory results. The use of a dental film placed within the wound also has been shown to be satisfactory.