Carotid Artery Stenting Outcomes in Comprehensive Stroke Hospitals: A Multicenter Study

Background Carotid artery disease, a major cause of strokes, often results from carotid atherosclerotic stenosis. As previously demonstrated in the CASONI registry, Operator experience plays a crucial role in reducing complications, with fellowship‐trained neurointerventionalists (NIRs) demonstrating proficiency in CAS. NIRs are uniquely positioned to perform CAS, given their expertise in cerebrovascular interventions; yet their outcomes remain underrepresented in large studies. The Carotid Artery Stenting Outcomes in Comprehensive Stroke Hospitals (CASSH) study evaluates real‐world CAS outcomes performed by fellowship‐trained NIRs at comprehensive stroke centers (CSCs). Methods CASSH is a multicenter, prospective observational study across 15 CSCs (January 2023‐December 2024). Adults with symptomatic ≥50% or asymptomatic ≥70% carotid stenosis undergoing CAS by fellowship‐trained NIRs were included. Demographics, comorbidities, procedural variables, and physician training were recorded. The primary endpoint was 30‐day periprocedural death, ischemic or hemorrhagic stroke, or myocardial infarction (MI). Secondary outcomes included nonprocedural mortality, access site complications, stent thrombosis, and other adverse events. Logistic regression identified predictors of outcomes. Results Among 889 patients with mean age 70.3 years (SD, 9.89); 61.4% male, 63.1% were symptomatic and 87.1% hypertensive. The primary outcome occurred in 1.2%, including procedure‐related mortality (0.8%), ischemic stroke (0.3%), hemorrhagic stroke (0.2%), and MI (0.2%). Secondary outcomes occurred in 5.4% of cases, most commonly access site complications (1.7%), non‐procedure‐related mortality (1.5%), and transient ischemic events (0.6%). Independent predictors of adverse outcomes included higher preprocedural mRS (primary: OR 1.42, 95% CI 1.01‐2.00; secondary: OR 1.37, 95% CI 1.16‐1.62; mortality: OR 1.72, 95% CI 1.32‐2.24) and NIHSS (primary: OR 1.09, 95% CI 1.01‐1.18; secondary: OR 1.11, 95% CI 1.07‐1.16; mortality: OR 1.15, 95% CI 1.09‐1.22). Older age (OR 1.05 per year, 95% CI 1.00‐1.11) and lower ejection fraction (OR 0.96, 95% CI 0.92‐1.00) significantly increased mortality risk. Importantly, postprocedural oral antiplatelet therapy significantly reduced both primary complications (OR 0.03, 95% CI 0.00‐0.36) and mortality (OR 0.07, 95% CI 0.01‐0.66). ROC analysis demonstrated optimal thresholds of mRS ≥3 for predicting primary and secondary outcomes. Conclusion CAS performed by fellowship‐trained NIRs at CSCs was associated with low rates of periprocedural stroke, myocardial infarction, and death comparable to or better than prior CAS and CEA reports. Outcomes were primarily driven by preprocedural disability (mRS), stroke severity (NIHSS), and patient age, with ejection fraction also influencing survival, particularly at the clinically relevant threshold of mRS ≥3. These findings highlight the importance of meticulous patient selection and optimization of perioperative management.