Surgical therapy for chronic internal carotid artery occlusion: a systematic review and meta-analysis

Chronic internal carotid artery occlusion (CICAO) significantly increases the risk of recurrent stroke. Given unfavorable outcomes, revascularization procedures are not generally recommended for CICAO. In the last several years, loads of studies reported successful surgical revascularization for CICAO with promising success rate and favorable short-term outcomes. Meanwhile, due to the lack of high-quality evidence, the safety and efficacy of revascularization procedures remain debatable. This systematic review aims to scrutinize current evidence for the applicability of revascularization for CICAO. We also investigated potential predictors of postoperative prognosis. We searched clinical studies on surgical treatment of CICAO on the Medline, Cochrane library, and Embase databases, published from Jan 1990 to Jan 2021. Surgical operation was restricted to bypass surgery, endarterectomy, endovascular therapy, and hybrid surgery. Controlled clinical studies were included for clinical outcomes. Large-sample single-arm studies were supplemented to assess complications and success rate. Co-primary endpoints were technical success rate and neurological function; secondary endpoints were recurrent stroke/cerebrovascular events, complications, and deaths within follow-up. This systematic review has been registered in PROSPERO (CRD42020181250). One RCT and 5 cohort studies with a total of 465 patients were included in this review. Seven single-arm studies were supplemented for assessing success rate and complications. Bypass surgery presented the highest graft patency of 96% and a low incidence of complications, but no benefits on neurological function, recurrent stroke, or deaths. Endovascular therapy (carotid stenting) was characterized by a relatively lower technical success rate, significant neurological function recovery, and nonsignificant reduction of cerebrovascular events and deaths. Hybrid surgery was considered as a potential treatment for CICAO because of a high technical success rate and significant neurological improvement. Endarterectomy is only suitable for short-segment occlusion. Prospective clinical trials should focus on carotid stenting and hybrid surgery for their significant capacity of improving neurologic function and potential capacity of reducing deaths and cerebrovascular events.