Carotid Artery Stenting Outcomes in Comprehensive Stroke Hospitals (CASSH): A Prospective Multicenter Study

The CASONI study (Carotid Artery Stenting Outcomes by Neurointerventional Surgeons) showed that proceduralist experience significantly reduces complications in carotid artery stenting. The CASSH study (Carotid Artery Stenting Outcomes in Comprehensive Stroke Hospitals) prospectively evaluates real-world carotid artery stenting outcomes by fellowship-trained neurointerventionalists at comprehensive stroke centers across the United States to validate and expand on CASONI's findings.

CASSH is a multicenter, prospective observational study conducted across 15 US comprehensive stroke centers from January 2023 to December 2024. Adults with symptomatic ≥50% or asymptomatic ≥70% carotid stenosis undergoing carotid artery stenting by fellowship-trained neurointerventionalists were included. The primary outcome was a 30-day composite of procedure-related death, stroke, or myocardial infarction. Secondary outcomes included nonprocedural mortality, access site complications, stent thrombosis, and other adverse events. Logistic regression identified predictors of adverse outcomes.

Among 889 patients (mean age 70.3±9.9 years; 61.4% male), 87.1% had hypertension and 63.1% were symptomatic. The 30-day composite primary outcome occurred in 1.2% (mortality 0.8%, ischemic stroke 0.3%, hemorrhagic stroke 0.2%, myocardial infarction 0.2%). Composite secondary outcome occurred in 5.4%, most commonly access site complications (1.7%) and nonprocedural mortality (1.5%). Higher preprocedural modified Rankin Scale (odds ratio [OR], 1.42), National Institutes of Health Stroke Scale score (OR, 1.09), and longer fluoroscopy times (OR, 1.02) were associated with increased complication risk. Mortality was independently predicted by elevated modified Rankin Scale (OR, 1.72), higher National Institutes of Health Stroke Scale score (OR, 1.15), older age (OR, 1.05 per year), and lower ejection fraction (OR, 0.96). Postprocedural antiplatelet therapy was protective, reducing both complications (OR, 0.03) and mortality (OR, 0.07).

Carotid artery stenting performed by fellowship-trained neurointerventionalists at comprehensive stroke centers is associated with low rates of periprocedural stroke, myocardial infarction, and death. These outcomes align with the landmark CREST-2 trial (Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis Trial), particularly in asymptomatic patients, and are strongly influenced by preprocedural disability, stroke severity, age, and cardiac function, underscoring the importance of patient selection and optimized perioperative care.