Baseline Patient Characteristics by Whether the Patient Was Taking an Antithrombotic Medication at the Time of the Qualifying Event Characteristic Taking Antithrombotic

B efore the publication of the results of the stenting versus aggressive medical therapy for intracranial arterial ste-nosis (SAMMPRIS) trial, the Wingspan stent was being used in clinical practice as a rescue treatment to prevent recurrent stroke in patients with 50% to 99% intracranial arterial steno-sis who had a transient ischemic attack or stroke when on anti-thrombotic therapy (AT). The rationale for this approach was uncertain because the preceding warfarin aspirin symptomatic intracranial disease (WASID) trial had shown similar rates of recurrent stroke on medical treatment alone in patients whose qualifying event (QE) for that trial occurred on versus off AT. 1 SAMMPRIS showed that patients with a transient ischemic attack or stroke within 30 days before enrollment that was attributed to a high grade, 70% to 99%, stenosis of a major intracranial artery had greater benefit from aggressive medical management alone (AMM) than with percutaneous trans-luminal angioplasty and stenting with the Wingspan stent plus aggressive medical management (PTAS). 2,3 SAMMPRIS did not require patients to be refractory to AT to be enrolled in the trial, which provided us with the opportunity to determine whether stenting is a rescue therapy for patients with a transient ischemic attack or stroke when on AT (so-called anti-thrombotic failures) and to compare the outcomes between patients whose QE for SAMMPRIS occurred on versus off AT. We report the results of these prespecified analyses in this article. Background and Purpose—Stenting has been used as a rescue therapy in patients with intracranial arterial stenosis and a transient ischemic attack or stroke when on antithrombotic therapy (AT). We determined whether the stenting versus aggressive medical therapy for intracranial arterial stenosis (SAMMPRIS) trial supported this approach by comparing the treatments within subgroups of patients whose qualifying event (QE) occurred on versus off of AT. Methods—The primary outcome, 30-day stroke and death and later strokes in the territory of the qualifying artery, was compared between (1) percutaneous transluminal angioplasty and stenting plus aggressive medical therapy (PTAS) versus aggressive medical management therapy alone (AMM) for patients whose QE occurred on versus off AT and between (2) patients whose QE occurred on versus off AT separately for the treatment groups. Results—Among the 284/451 (63%) patients who had their QE on AT, the 2-year primary end point rates were 15.6% for those randomized to AMM (n=140) and 21.6% for PTAS (n=144; P=0.043, log-rank test). In the 167 patients not on AT, the …