Impact of Stenosis Degree on Outcomes of Stenting versus Medical Treatment Alone for Symptomatic Intracranial Stenosis: A Pooled Individual Patient Data Analysis

BACKGROUND AND PURPOSE: This study explores the impact of stenosis degree on outcomes of stenting compared with medical therapy alone in patients with symptomatic intracranial artery stenosis.

MATERIALS AND METHODS: Patients with a transient ischemic attack or nondisabling ischemic stroke, attributed to 70 to 99% stenosis of a major intracranial artery, were included. The patient cohort was drawn from the China Angioplasty and Stenting for Symptomatic Intracranial Severe Stenosis (CASSISS) and the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS). The primary outcome was a composite of stroke or death within 30 days or stroke in the qualifying artery territory beyond 30 days through 1 year.

RESULTS: Out of 806 patients, 92 patients (11%) met the primary outcome. As the degree of stenosis increased, the risk of the primary endpoint was significantly lower in the stenting group (R = -0.886, P = .03). For stenosis below or equal to 85%, stenting is worse than medical therapy given the high perioperative risk [13% vs. 8.0%, HR, 1.67, (95% CI, 1.04-2.67); P = .04]; at stenosis degree above 85%, stenting was preferred over medical therapy given the potential for better long-term prevention [14% vs. 21%, HR, 0.67, (95% CI, 0.29-1.56); P = .36].

CONCLUSIONS: Patients with higher degrees of stenosis are more likely to benefit from stenting. Patients with intracranial artery stenosis exceeding 85% may be the focus of future studies. If innovations in interventional techniques significantly reduce perioperative risk, the critical threshold of 85% as the degree of stenosis might be reconsidered.

ABBREVIATIONS: CASSISS = China Angioplasty and Stenting for Symptomatic Intracranial Severe Stenosis; SAMMPRIS = Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis; ICAS = Intracranial atherosclerotic arterial stenosis; WASID = Warfarin versus Aspirin for Symptomatic Intracranial Disease; VISSIT = Vitesse Intracranial Stent Study for Ischemic Stroke Therapy; PH = proportional hazards; HR = Hazard ratio