c l i n i c a l f o l i o s : d i s c u s s i o n

Carotid Endarterectomy



Related narratives: Carotid Endarterectomy, Carotid Endarterectomy (Video)

Near total occlusion of the internal carotid artery poses diagnostic and therapeutic questions. Ultimately, angiogram is still the gold standard for the most sensitive assessment of the situation. In this case, it corrected the impression on ultrasound and MRA that there was total occlusion and retrograde distal filling. In addition, critical information about this patient's negligible collateral cerebral circulation was obtained. The surgeons were alerted to the increased risk of occluding the right external carotid in the course of the endarterectomy since this was the primary source of right middle cerebral inflow.

The use of the shunt, local anesthesia, EEG and cerebral oxygen monitoring all decreased the chance of cerebral compromise during surgery. The cerebral oxygen monitoring shows promise for establishing the need for a shunt in carotid surgery, as well as for intraoperative monitoring of neurosurgical patients. The atheromatous plaque starts as subintimal lipid deposits and ultimately destroys the intima and partial thickness of the media. Dissection of the plaque from the remaining vessel wall leaves a shell of media and adventitia, so separation must be meticulous and careful.

Most of the time, the distal plaque feathers smoothly when the plaque is slowly pulled. In such cases, tacking sutures may not be necessary. In this case, despite ample distal exposure beyond the plaque, the distal end failed to feather, and it was elected to cleanly transect it and tack the distal cut edge. If further exposure is necessary for the distal internal carotid, maneuvers such as mandibular subluxation can be used.

Dr. Valentine comments:

The authors used a number of techniques to monitor the patient in this operation. The most sensitive technique is to monitor the patient in the awake state, as was done in this case. The addition of EEG monitoring and cerebrovascular oxygenation monitoring are costly and do not add anything to the safety of the procedure (the latter is experimental).

Since the authors planned to use a shunt in this procedure regardless of intraoperative changes, there were few advantages of using local vs. general anesthesia in this case. Please discuss.

Why did the authors patch the carotid, and why did they use Dacron over vein or PTFE. Please discuss. These are important points in the literature.

Dr. Rothstein replies:

The use of the EEG and the cerebral oxygenation monitoring were used to gather information on their ability to predict cerebral ischemia and allowed the opportunity to use and learn about other monitoring devices. Indeed at one point in the procedure after deshunting there was a decrease in the cerebral oximetry and a change in the EEG waveforms while the patient remained asymptomatic. These objective findings preceded any clinical symptomatology and their relevance is debatable. They both subsequently returned to baseline following restoration of cerebral blood flow.

The surgeons in this procedure routinely shunt all carotid endarterectomies. Local anesthesia was used in this case because the differential of carotid dissection was considered upon reviewing the angiogram. If this was the situation and the dissection extended into the skull base, the options at that time would be ligation vs. intracranial extracranial bypass. This would depend on the patient's response to carotid clamping.

A dacron patch was used because the authors have experienced less bleeding from needle holes than with the PTFE. I do not routinely use vein patches because there have been previous reports of aneurysmal dilation (although more so when the vein is taken from the lower leg.) Also these patients have a systemic disease of atherosclerosis and may very well need that vein at another time and it is a limited commodity. There is no convincing and consistent literature that supports preferential use of vein patches.

The author routinely drains the carotid endarterectomies for 24 hours while virtually never reversing heparinization. Very minimal morbidity, cost, or cosmetic difference. A matter of training.

This page was last modified on 18-Nov-2000.