Preoperative computed tomography perfusion and angiography predict the need for shunting in carotid endarterectomy: a
Yong Liu1,2, Yongle Sun1, Quanzhi Feng3
1Department of Neurosurgery, Tianjin First Central Hospital, Tianjin, China.
Background:
Although selective shunting placement during carotid endarterectomy (CEA) may reduce the risk of clamp-induced cerebral ischemia, validated quantitative predictors for its requirement are currently unavailable. This study aimed to investigate the predictive value of combining preoperative quantitative computed tomography perfusion (CTP) with computed tomography angiography (CTA) for determining the necessity of intraoperative shunt placement.
Methods:
A total of 283 patients who underwent CEA were retrospectively analyzed at two tertiary medical centers. The two hospitals followed distinct surgical protocols: Hospital I (Tianjin First Central Hospital, n=126) used intraoperative monitoring to guide selective shunting (n=20); Hospital II (Tianjin Huanhu Hospital, n=157) adopted a routine non-shunting approach with pharmacologic blood pressure elevation during clamping. Preoperative relative cerebral blood flow (rCBF) and circle of Willis (CoW) integrity were assessed using combined quantitative CTP and CTA. We performed univariate and multivariate logistic regression to identify independent predictors of shunting (Hospital I) and postoperative cerebral infarction (Hospital II), with model performance evaluated by receiver operating characteristic (ROC) curve analysis. For external validation, predictors from Hospital I were tested in Hospital II to assess generalizability. Subgroup analyses were conducted based on key clinical features, incorporating interaction terms in logistic models and stratified ROC analysis to examine stratum-specific discriminative performance.
Results:
In Hospital I, both lower rCBF [odds ratio (OR) =0.35, 95% confidence interval (CI): 0.12-0.89, P<0.001] and an incomplete CoW (OR =5.47, 95% CI: 1.70-17.59, P=0.04) were identified as independent predictors for shunting necessity. Similarly, in Hospital II, lower rCBF (OR =0.21, 95% CI: 0.10-0.44, P<0.001) and an incomplete CoW (OR =7.22, 95% CI: 1.99-26.24, P=0.003) served as independent risk factors for postoperative cerebral infarction. ROC curve analysis determined the optimal rCBF cutoff to be 53.5%, which yielded an area under the curve (AUC) of 0.82 (95% CI: 0.71-0.93), a sensitivity of 92.5%, and a specificity of 70.0%. Crucially, external validation in Hospital II demonstrated that identical rCBF threshold (≤53.5%) functioned as a robust independent predictor for postoperative cerebral infarction, with a sensitivity of 79.9% and specificity of 83.3%. Subgroup and interaction analyses further confirmed that the predictive performance of this rCBF cutoff was not significantly modified by preoperative symptomatic status (P=0.70) or the severity of contralateral carotid artery stenosis (P=0.84).
Conclusions:
Preoperative quantitative CTP combined with CTA can predict the need for shunt placement during CEA, with the potential to optimize shunt use, improve surgical outcomes, and enhance perioperative patient safety.
