Introduction: To assess the possible role and the interaction of cerebrovascular disease and vascular stenosis on the necessity of shunt insertion during carotid endarterectomy (CEA).
Material and methods: Eighty consecutive patients undergoing CEA under regional anaesthesia were prospectively enrolled. Patients were divided into two groups depending on whether they were shunted or not. The measured end-points were co-morbidities degree of contralateral and carotid stenosis and other intra- and postoperative outstanding parameters. ANOVA, Student’s t and 2 tests were used (p < 0.05). Variables differing significantly between groups and potential confounders were used in backward stepwise logistic regression to estimate the relative risk (RR, 95% CI) of shunt. In addition Wald’s test (p < 0.05) with and without adjustments for potential confounders was used with various different multivariate analysis models.
Results: Contralateral stenosis and cerebral vascular accidents (CVA) were more frequently observed in shunted patients. The RR for patients with contralateral stenosis  50% was 1.3 (95% CI 1.0-1.5) and for patients with previous CVA was 1.2 (95% CI 1.0-1.4). For contralateral stenosis and CVA together the RR increased to 7.7 (95% CI 1.0-14.4). A model based on contralateral stenosis and CVA was found to be statistically significant (p = 0.003) for shunt (RR = 1.1, 95% CI 1.0-2.1). Relative excess risk due to interaction of both factors was 6.2.
Conclusions: The findings suggest that patients with contralateral stenosis  50% and previous CVA have a higher risk of requiring shunt use during CEA than patients with these risk factors separately.