Internal Carotid Artery Tortuosity: Impact on Mechanical Thrombectomy

Abstract

Background: Although tortuosity of the internal carotid artery (ICA) can pose a significant challenge when performing mechanical thrombectomy, few studies have examined the impact of ICA tortuosity on mechanical thrombectomy outcomes.

Methods: In a registry-based hospital cohort, consecutive patients with anterior circulation stroke in whom mechanical thrombectomy was attempted were divided into 2 groups: those with tortuosity in the extracranial or cavernous ICA (tortuous group) and those without (nontortuous group). The extracranial ICA tortuosity was defined as the presence of coiling or kinking. The cavernous ICA tortuosity was defined by the posterior deflection of the posterior genu or the shape resembling Simmons-type catheter. Outcomes included first pass effect (FPE; extended Thrombolysis in Cerebral Infarction score 2c/3 after first pass), favorable outcome (3-month modified Rankin Scale score of 0-2), and intracranial hemorrhage.

Results: Of 370 patients, 124 were in the tortuous group (extracranial ICA tortuosity, 35; cavernous ICA tortuosity, 70; tortuosity at both sites, 19). The tortuous group showed a higher proportion of women and atrial fibrillation than the nontortuous group. FPE was less frequently achieved in the tortuous group than the nontortuous group (21% versus 39%; adjusted odds ratio, 0.45 [95% CI, 0.26-0.77]). ICA tortuosity was independently associated with the longer time from puncture to extended Thrombolysis in Cerebral Infarction ≥2b reperfusion (β=23.19 [95% CI, 13.44-32.94]). Favorable outcome was similar between groups (46% versus 48%; P=0.87). Frequencies of any intracranial hemorrhage (54% versus 42%; adjusted odds ratio, 1.61 [95% CI, 1.02-2.53]) and parenchymal hematoma (11% versus 6%; adjusted odds ratio, 2.41 [95% CI, 1.04-5.58]) were higher in the tortuous group. In the tortuous group, the FPE rate was similar in patients who underwent combined stent retriever and contact aspiration thrombectomy and in those who underwent either procedure alone (22% versus 19%; P=0.80). However, in the nontortuous group, the FPE rate was significantly higher in patients who underwent combined stent retriever and contact aspiration (52% versus 35%; P=0.02).

Conclusions: ICA tortuosity was independently associated with reduced likelihood of FPE and increased risk of postmechanical thrombectomy intracranial hemorrhage.

Registration: URL: https://www.

Clinicaltrials: gov; Unique identifier: NCT02251665.

Keywords: catheters; intracranial hemorrhages; punctures; reperfusion; thrombectomy.

Figures

Figure 1.

Classification of extracranial and cavernous internal carotid artery (ICA) tortuosity. A, Tortuosity of the extracranial ICA was classified into 4 types as follows: straight (angle between the centerlines of the common carotid artery and the ICA was <15°), tortuous (angle between the common carotid artery and the ICA centerlines was >15; or S- or C-shaped course of the ICA), coiled (an exaggerated S-shaped curve or circular configuration of the ICA), and kinked (acute [<90°] angulation associated with stenosis). The extracranial ICA was considered tortuous if it was coiled or kinked. B, Cavernous ICA tortuosity was classified into 4 types based on the geometry of the anterior and posterior genus. Type I has open configurations/angles of anterior and posterior genus (the posterior genu angle [P] ≥90°). Type II is characterized by a closed configuration of the anterior genu (more acute angle of the anterior genu [A] than type I). Type III is defined by posterior deflection of the posterior genu, which gives it a buckled appearance. Type IV is the most tortuous and has a shape characteristic of the Simmons-style angiography catheter where the posterior genu is buckled superiorly compared with the anterior genu. H is the height difference of the anterior and posterior genus, measured from the peak of the posterior genu to the trough of the anterior genu. Types III and IV were considered tortuous cavernous ICA.

Figure 2.

Study flowchart. ICA indicates internal carotid artery; M1, first segment of the middle cerebral artery; M2, second segment of the middle cerebral artery; MT, mechanical thrombectomy; and NCVC, National Cerebral and Cardiovascular Center.

Figure 3.

Procedural outcomes according to the location of internal carotid artery (ICA) tortuosity. Outcomes according to location of ICA tortuosity are shown for (A) reperfusion status after first pass, (B) final reperfusion status, and (C) intracranial hemorrhage. eTICI indicates extended Thrombolysis in Cerebral Infarction.

Figure 4.

First pass effect according to the first-line mechanical thrombectomy strategy. The rate of first pass effect according to the first-line mechanical thrombectomy strategy in the (A) nontortuous and (B) tortuous internal carotid artery groups. CA indicates contact aspiration; NS, nonsignificant; and SR, stent retriever. *Fisher exact test.