Outcomes and role of shunting during carotid endarterectomy for symptomatic patients.

Abstract

Shunt placement during carotid endarterectomy (CEA) has often been advocated to protect the ischemic penumbra in patients with symptomatic carotid stenosis. In the present study, we assessed the effect of shunt placement during CEA on postoperative stroke risk in symptomatic patients. We queried the American College of Surgeons National Surgical Quality Improvement Program database (2016-2019) for CEA cases with complete CEA procedure-targeted data available. Symptomatic patients were identified as those with a preoperative diagnosis of stroke on presentation (DS), transient ischemic attack, amaurosis fugax, or temporary monocular blindness. The DS patients were further analyzed according to the severity of their stroke using the modified Rankin scale scores. To better assess the effect of shunt placement on the stroke rate, we compared cases of CEA with the patch angioplasty technique stratified by the use of an intraoperative shunt. Patients who had undergone carotid eversion or primary closure were excluded. The baseline demographics and perioperative outcomes were compared using the χ2 and Mann-Whitney U tests. Multivariate analysis was performed to identify the independent risk factors for postoperative stroke and cranial nerve injury. We identified 4652 cases of CEA with patch angioplasty in symptomatic patients, including 1889 with (40.6%) and 2763 without (59.4%) shunt placement. The distribution of age, race, and sex was similar for both procedures. Compared with patients without a shunt, those with a shunt had significantly higher rates of emergency surgery (9.1% vs 7.0%; P= .010), nonelective surgery (40.3% vs 37.2%; P= .035), general anesthesia (97.0% vs 86.3%; P< .001), and bleeding disorders (27.2% vs 22.7%; P< .001). The 30-day incidence of postoperative stroke was similar between the patients with (3.2%) and without (2.6%) shunt placement (P= .219). Additionally, a subgroup analysis failed to show any benefit from shunt placement on the incidence of postoperative stroke, regardless of the preoperative symptoms or neurologic disability. In contrast, shunt placement was associated with an increased rate of cranial nerve injury (4.1% vs 2.4%; P= .001). Multivariate analysis revealed that nonelective surgery (odds ratio [OR], 1.99; 95% confidence interval [CI], 1.36-2.91; P< .001) and DS (vs transient ischemic attack, amaurosis fugax, or temporary monocular blindness; OR, 1.64; 95% CI, 1.12-2.41; P= .012) were predictive of 30-day postoperative stroke. After adjusting for confounders, shunt placement had no effect on stroke risk at 30days but remained an independent risk factor for cranial nerve injury (adjusted OR, 1.87; 95% CI, 1.32-2.64; P< .001). For symptomatic patients undergoing CEA with patch angioplasty, shunt placement was associated with an increased risk of cranial nerve injury without a reduction in postoperative stroke risk.