Contralateral stroke during carotid endarterectomy due to abnormalities in the circle of Willis

Abstract

Approximately 10-20% of patients will not tolerate cross-clamping of the common carotid artery for carotid endarterectomy procedures. The most frequent causes of neurological deficits are either embolization of particulate matter or cerebral hypoperfusion. Insufficient blood flow through primary collaterals of the circle of Willis is the main reason for hypoperfusion that requires immediate shunt placement. Although excessive preoperative imaging is not indicated in many patients undergoing disobliteration of a stenosed internal carotid artery, there are some patients with particular anatomic constellations who would benefit from a more detailed preoperative work-up. In these cases, the specific risk should be evaluated prior to surgery in order to make plans for appropriate intraoperative management regarding neurologic monitoring and shunt insertion. As regional anesthesia permits early detection of ischemic symptoms, it is advantageous in these patients. We report a case where regional anesthesia allowed early detection of rapidly progressing signs of bi-hemispheric brain ischemia in a patient with diabetes and with at that time unknown severe abnormalities of the circle of Willis. Lack of adequate collateralization was detected only after surgery, in a combined perfusion-magnetic resonance imaging study. In symptomatic diabetics with low-grade stenosis of the internal carotid artery, preoperative assessment of the function of the circle of Willis may therefore be helpful in predicting any increased risk for intraoperative cerebral ischemia.

Demographic age-related variation in Circle of Willis completeness assessed by digital subtraction angiography

“…[11] Acute ischemic stroke risk is similarly elevated in individuals with variant CoW configurations. [5,[12][13][14][15][16][17][18] Individuals with good cerebral collateral circulation tend to have smaller infarct size at baseline and higher rates of neurological improvement following acute ischemic stroke. [19,20] A recent work by Zaninovich et al [21] supports the emerging theory that age and gender have a significant effect on the rates of complete CoW, which subsequently impacts these disease states.…”

Hippocampal cellular loss after brief hypotension

“…Maintenance of adequate blood flow to the brain is necessary in the course of general anesthesia in order to assure safe recovery and normal brain function after surgical intervention (Rubio et al 2008; Moritz et al 2007). Predictable models of neuronal loss after progressive low blood pressure insults have been developed (Yamauchi et al 19901991) For instance, Yamauchi and colleagues described selective progressive damage to regions of the brain after two or three minute episodes of profound hypotension (low blood pressure, 25 mmHg) one week after the hypotensive insult (Yamauchi et al 19901991).…”

Internal carotid artery agenesis and contralateral middle cerebral artery infarction

“…The fact that the patient remained asymptomatic until the age of 65 years supports the welldevelopment of collateral circulation in these patients. While collateral flow through the Willis circle is usually sufficient to prevent cerebral ischemia during carotid clamping, an incomplete and dysfunctional circle poses increased risk [9,10]. Agenesis of the ICA is a rare condition that alters the collateral circulation in the circle.…”