Anatomic eligibility for transcarotid artery revascularization and transfemoral carotid artery stenting

Abstract

Objective: Transcarotid artery revascularization (TCAR) has emerged as an alternative to transfemoral carotid artery stenting (tfCAS). We investigated the proportion of carotid arteries undergoing revascularization procedures that would be eligible for TCAR based on anatomic criteria and how many arteries at high anatomic risk for tfCAS would be amenable to TCAR.

Methods: We performed a retrospective review of consecutive patients who underwent carotid endarterectomy or carotid stenting between 2012 and 2015. Patients were excluded if computed tomography angiography of the neck was not performed within 6 months of the procedure. We assessed TCAR eligibility on the basis of the instructions for use of the ENROUTE Transcarotid Neuroprotection System (Silk Road Medical, Sunnyvale, Calif) and high anatomic risk for tfCAS on the basis of anatomic factors known to make carotid cannulation more difficult or hazardous.

Results: Of the 118 patients and 236 carotid arteries identified, 12 carotid arteries were excluded for presence of an occluded internal carotid artery (ICA). Of the remaining 224 carotid arteries, 72% were eligible for TCAR on the basis of the instructions for use criteria; 100% had 4- to 9-mm ICA diameters, 100% had ≥6-mm common carotid artery (CCA) diameter, 75% had ≥5-cm clavicle to carotid bifurcation distance, and 96% lacked significant CCA puncture site plaque. In addition, 7% of carotid arteries had bifurcation anatomy unfavorable for stenting; thus, of the entire cohort of arteries examined, 68% were eligible for TCAR. Hyperlipidemia (odds ratio [OR], 6.7; 95% confidence interval [CI], 1.7-26; P < .01), chronic obstructive pulmonary disease (OR, 3.5; 95% CI, 1.5-8.3; P < .01), and older age (OR, 1.1; 95% CI, 1.0-1.1; P < .01) were independently associated with TCAR ineligibility, whereas white race (OR, 0.2; 95% CI, 0.0-1.0; P = .048) and beta-blocker use (OR, 0.3; 95% CI, 0.1-0.7; P < .01) were independently associated with TCAR eligibility. In addition, 24% of carotid arteries were considered to be at high risk for tfCAS for the presence of a type III aortic arch (7.6%), severe aortic calcification (3.3%), tandem CCA lesions (7.1%), moderate to severe stenosis at the carotid ostium (8.9%), and tortuous distal ICA precluding embolic filter placement (4.5%). Active smoking (OR, 4.4; 95% CI, 1.9-10; P < .01), hyperlipidemia (OR, 4.0; 95% CI, 1.2-14; P = .03), and older age (OR, 1.1; 95% CI, 1.0-1.1; P = .02) were independently associated with tfCAS ineligibility, whereas preoperative aspirin (OR, 0.1; 95% CI, 0.0-0.4; P < .001) or clopidogrel (OR, 0.3; 95% CI, 0.1-0.8; P = .01) use was associated with tfCAS eligibility. Of the arteries that were considered to be at high risk for tfCAS, 69% were eligible for TCAR.

Conclusions: The majority of carotid arteries in individuals selected for revascularization meet TCAR eligibility, making TCAR a viable treatment option for many patients.

Keywords: Carotid artery; Eligibility; Transcarotid artery revascularization.

Figure 1:

Inclusion and exclusion criteria for evaluating TCAR and tfCAS eligibility

Figure 2:

Measurements performed for transcarotid artery revascularization. Cla-Bi, clavicle-bifurcation distance; cm, centimeters; LCCA, left common carotid artery.