China Angioplasty and Stenting for Symptomatic Intracranial Severe Stenosis - CASSISS

Contribution To Literature:

Among patients with TIA or ischemic stroke with severe intracranial atherosclerotic stenosis in the CASSISS trial, percutaneous angioplasty and stenting with medical therapy did not lead to a difference in risk of stroke or death compared with medical therapy alone.


The goal of the trial was to evaluate the efficacy of stenting and medical therapy versus medical therapy alone on mortality and stroke among patients with transient ischemic attack (TIA) or ischemic stroke with severe intracranial atherosclerotic stenosis.

Study Design

CASSISS was a multicenter, randomized, open-label trial of patients with a TIA or nondisabling ischemic stroke with 70-99% stenosis of a major intracranial artery. Patients were randomized in 1:1 fashion to medical therapy plus stenting (n = 188) versus medical therapy alone (n = 192). Medical therapy included aspirin 100 mg and clopidogrel 75 mg daily for 90 days, followed by aspirin or clopidogrel monotherapy, and hypertension and lipid treatment. The Wingspan stent was utilized, and the intervention occurred within 3-5 days after randomization.

  • Total screened: 1,152
  • Total randomized participants: 380
  • Mean patient age: 56 years
  • Percentage male: 73.5%

Inclusion criteria:

  • TIA or nondisabling ischemic stroke
  • Severe stenosis of a major intracranial artery (70-99%)

Exclusion criteria:

  • TIA or ischemic stroke within 3 weeks of screening
  • Brainstem or basal ganglia perforator stroke only
  • Prespecified unfavorable anatomic features
  • Previous endovascular treatment

Other salient features/characteristics:

  • 54.2% with index stroke as qualifying event
  • 59.3% with artery-to-artery embolism as mechanism of stroke
  • Symptomatic qualifying artery: M1 40%, basilar artery 28%, intracranial vertebral 22%
  • Median modified Rankin scale (mRS) score: 0

Principal Findings:

The primary outcome, a composite of stroke or death within 30 days after enrollment or stroke beyond 30 days and 1 year in the territory of the qualifying artery, for medical therapy and stenting versus medical therapy alone, was 8.0% vs. 7.2% (p = 0.82).

Secondary outcomes for medical therapy and stenting vs. medical therapy alone:

  • Stroke in the same territory within 2 years: 9.9% vs. 9.0% (p = 0.80)
  • Death within 3 years: 4.4% vs. 1.3% (p = 0.08)
  • Intracranial hemorrhage within 30 days: 2.3% vs. 0%


The results of this trial show that, among patients with severe intracranial atherosclerotic stenosis and TIA or stroke, treatment with stenting and medical therapy resulted in no significant difference in risk of subsequent stroke or death compared to medical therapy alone. The results of this trial confirm the benefits of medical therapy for symptomatic severe intracranial atherosclerotic stenosis.

Importantly, this trial utilized a strategy of vetting operators and sites, which should have optimized procedural technique and outcomes. Despite this, there was potentially a signal for harm with the stenting group, with a numerically higher death rate at 3 years, and numerically higher 30-day symptomatic intracranial hemorrhage rate. Finally, the 1-year stroke and death risks were lower in both arms compared to previous trials, which is likely due to exclusion of high-risk patients with ischemic symptoms within 3 weeks of trial enrollment. Also, although details of medical therapy in the current trial are not provided, there have been significant advances in this field overall compared with prior years. The current study findings do not support addition of angioplasty and stenting to medical therapy for treatment of symptomatic severe intracranial atherosclerotic stenosis.


Gao P, Wang T, Wang D, et al. Effect of Stenting Plus Medical Therapy vs Medical Therapy Alone on Risk of Stroke and Death in Patients With Symptomatic Intracranial Stenosis: The CASSISS Randomized Clinical Trial. JAMA 2022;328:534-42.

Editorial: Anderson CS, Song L, Liu J. Therapeutic Strategies for Intracranial Atherosclerosis. JAMA 2022;328:529-31.

Clinical Topics: Dyslipidemia, Invasive Cardiovascular Angiography and Intervention, Prevention, Vascular Medicine, Lipid Metabolism, Interventions and Vascular Medicine, Hypertension

Keywords: Angioplasty, Aspirin, Atherosclerosis, Clopidogrel, Constriction, Pathologic, Coronary Stenosis, Embolism, Hypertension, Intracranial Arteriosclerosis, Intracranial Hemorrhages, Ischemic Attack, Transient, Ischemic Stroke, Lipids, Secondary Prevention, Stents, Stroke, Vascular Diseases

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