Predictors of Occlusion after Carotid Stenting

Carotid artery stent (CAS) occlusion is a rare complication not well studied. We used a national dataset to assess real world CAS experience to determine the rate of stent occlusion. The purpose of this study was to 1) Identify risk factors associated with CAS occlusion on long-term follow-up (LTFU) and 2) Determine the adjusted odds of death/transient ischemic attack (TIA)/stroke (cerebrovascular accident (CVA)) in patients with occlusion.

The national Vascular Quality Initiative CAS dataset (2016-2021) comprised the sample. The primary endpoint was occlusion on LTFU (9-21 months postoperatively as defined by the Vascular Quality Initiative LTFU dataset) with secondary endpoint examining a composite of death/TIA/CVA. Descriptive analyses used chi-square and Wilcoxon tests for categorical and continuous variables respectively. Adjustment variables were selected a priori based on clinical expertise and univariate analyses. Multivariable logistic regression was used to model the odds of occlusion and the odds of death/TIA/CVA. Generalized estimating equations accounted for center level variation.

During the study period, 109 occlusions occurred in 12,143 cases (0.9%). On univariate analyses, symptomatic indication, prior stroke, prior neck radiation, lesion calcification (>50%), stenosis (>80%), distal embolic protection device (compared to flow reversal), balloon size, >1 stent and current smoking at time of LTFU were predictive for occlusion. Age ≥ 65, coronary artery disease (CAD), elective status, preoperative statin, preoperative and discharge P2Y12 inhibitor, use of any protection device intraoperatively and protamine were protective. On multivariable analyses, age ≥ 65, CAD, elective status and P2Y12 inhibitor on discharge were protective for occlusion, while patients with prior radiation and those taking P2Y12 inhibitor on LTFU were at increased odds. The adjusted odds of death/TIA/CVA in patients with occlusion on LTFU were 6.05; 95% confidence interval: 3.61-10.11, P < 0.0001.

This study provides an in-depth analysis of predictors for CAS occlusion on LTFU. On univariate analyses, variables related to disease severity (urgency, degree of stenosis, nature of lesion) and intraoperative details (balloon diameter, >1 stent) were predictive for occlusion. These variables were not statistically significant after risk adjustment. On multivariable analyses, prior neck radiation was strongly predictive of occlusion. Elective status, patient age ≥ 65, CAD, and P2Y12 inhibitor upon discharge (but not on LTFU) were protective for occlusion. Additionally, patients who developed occlusion had high odds for death/TIA/CVA. These findings provide important data to guide clinical decision-making for carotid disease management, particularly identifying high-risk features for CAS occlusion. Closer postoperative follow-up and aggressive risk factor modification in these patients may be merited.