Territorial Stroke in SAMMPRIS: Critical Analyses of Stroke Prevention in Intracranial Atherosclerosis

Current guidelines do not support the addition of stenting to maximal medical therapy (MMT) for severe symptomatic intracranial atherosclerotic disease as first-line treatment. This is largely due to the SAMMPRIS trial (Stenting and Aggressive Medical Management Therapy for Preventing Recurrent Stroke in Intracranial Arterial Stenosis) results, which featured a high periprocedural stroke rate. In this study, we examined the rates of ischemic stroke in the territory of the qualifying artery (stroke in territory [SIT]) over time between MMT alone and stent+MMT.

The primary outcome was SIT. Periprocedural stroke was considered <7 days from stent placement. Log-rank analysis, Cox proportional hazards models, and Kaplan-Meier survival curves compared time to SIT between MMT and stent+MMT (day of stenting considered day 0).

In total, 435 patients were included (MMT: n=227; stent+MMT: n=208). The SIT event rate was 15.6% (68 events-MMT: n=31/227 (13.7%); stent+MMT: n=37/208 (17.8%). Twenty of the 37 stented patients had periprocedural SIT (7 early; 13 delayed). When periprocedural SIT was excluded, there were zero SIT events in the stent+MMT arm at 30 and 60 days, which was significantly lower than the MMT arm (P<0.01). Similarly, at 1 year, stent+MMT had a significantly lower rate of SIT (hazard ratio, 0.47 [95% CI, 0.23-0.98]; P=0.04). The difference in SIT between MMT and stent+MMT was not significant (P=0.2) over the entire follow-up period (1626 days), with 31 strokes in MMT and 17 nonperiprocedural strokes in stent+MMT (P=0.1). Thirteen patients with SIT were stented early (<7 days from qualifying ischemic event) with similar time of stent insertion to SIT compared to delayed stenting (P=0.9). Of patients with stent+MMT and SIT, there was no difference in periprocedural SIT based on early versus delayed stenting (P=0.9). No significant difference in total SIT was seen over time when compared between early and delayed stenting (P=0.6).

Contrary to Food and Drug Administration recommendations, periprocedural SIT rates did not vary by time of stenting after qualifying ischemic event. Most SIT was periprocedural, and the rate of SIT over the study period was higher in MMT when excluding periprocedural strokes. These findings are exploratory but may suggest that MMT alone may not be the most effective treatment for intracranial atherosclerotic disease and that with improvements in periprocedural safety, intracranial stenting may remain a viable treatment option.

URL: https://www.clinicaltrials.gov; Unique identifier: NCT00576693.