Subtle cerebral damage after shunting vs non shunting during carotid endarterectomy. Carotid endarterectomy: to shunt or not to shunt.
To compare the extent of subtle cerebral damage (SCD) in patients undergoing carotid endarterectomy with or without shunt placement.
                Prospective, randomised study.
                We assessed a consecutive series of 96 patients undergoing endarterectomy for severe unilateral left carotid stenosis who had been randomly assigned to receive a shunt (48) or not (48). Eligibility criteria included age up to 80 years and Mini-Mental State Examination score >24 points. Patients underwent neuropsychological testing before surgery. Serum concentrations of S100 protein, neuron-specific enolase (NSE) and interleukin-6 (IL-6) were measured intraoperatively before and after carotid clamping. Finally, each patient underwent neuropsychological testing 3 weeks after surgery.
                Patients with and without shunt had similar serum concentrations of S100 protein, NSE and IL-6 as well as similar neuropsychological test scores, all p>0.05.
                There was no difference in subtle cerebral damage between patients randomized to receive a shunt or not. Because of controversies in the cerebrovascular literature regarding the use of an intraluminal shunt in carotid endarterectomy, we report a randomized prospective study of 118 consecutive symptomatic patients receiving surgery within a single neurosurgical practice. Over 4 years, 138 carotid endarterectomies were performed in the 118 patients, 63 operations with intraluminal shunting and 75 without. Standard rationale for surgery included ipsilateral cerebral infarction in 38% of the operations and ipsilateral transient ischemic attacks in 36%. Unilateral angiographic stenosis of greater than 90% was seen in 58% of the operations; there were no ipsilateral occlusions. Surgery was performed under general anesthesia with barbiturate induction and mild blood pressure elevation. The 30-day complication rate included a mortality rate of 0.7% with a 5.1% incidence of postoperative neurologic deficit and a 1.4% rate of myocardial infarction. In the 24 hours after surgery there were no cerebral infarctions in the shunted group and six in the unshunted group. This 8% rate in the unshunted group compared with 0% in the shunted group was significant at p = 0.023 with a power of 0.95 by Fisher's exact test and chi 2 analysis. This suggests that in our neurosurgical practice (resident training program) the use of an intraluminal shunt during carotid endarterectomy significantly reduces the risk of intraoperative neurologic deficit without increasing the incidence of other complications.
This review concluded that the data available were too limited to either support or refute the use of routine or selective shunting in carotid endarterectomy. It was suggested that large scale randomised trials between routine shunting versus selective shunting were required. No one method of monitoring in selective shunting has been shown to produce better outcomes.