Using a prospective database, we studied carotid endarterectomy performed under locoregional anesthesia between January 1, 2003, and December 31, 2010 (n = 1,223). A shunt was used because of clinical intolerance of clamping in 88 cases (group S, 7.2%). Clinical, comorbidities, demographics, and duplex scan data were used to compare group S to a control group (group C, n = 1,135, 92.8%). A multivariable logistic regression was performed to identify predictors of shunt. Coefficients were assigned to each predictor to propose a predictive score.
Patients in group S were significantly older than those in group C (75.6 ± 7.8 years vs. 72.6 ± 9.4 years, P < 0.001). Other factors associated with a carotid shunt were female sex (odds ratio [OR] = 2.41, 95% confidence interval [CI]: 1.54–3.78, P < 0.001), systemic arterial hypertension (OR = 2.478, 95% CI: 1.16–4.46, P = 0.016), occlusion of the contralateral carotid artery (OR = 6.03, 95% CI: 2.91–12.48, P < 0.001), and 1 factor against the likelihood of a carotid shunt, a history of contralateral carotid surgery (OR = 0.34, 95% CI: 0.12–0.93, P = 0.037). The mean flow in the contralateral common carotid artery was 696.5 ± 298.0 mL/sec in group S and 814.7 ± 285.5 mL/sec in group C (P < 0.001). Using those 6 items, we propose a prognostic score validated in our series and allowing to divided risk of intolerance of clamping into low-risk (≤6%), intermediate-risk (6.1%–15%), and high-risk (>15%) groups.
We have established the first version of a score that predicts the need for a shunt by studying factors associated with intolerance to clamping. The relevance of this score, validated in our series, must be confirmed and adjusted by studies based on a larger sample size.