A subanalysis of the SAMMPRIS (Stenting vs. aggressive medical therapy for intracranial arterial stenosis) trial found that there were lower outcome events with aggressive medical management than with stenting, even in patients who had failed antithrombotic therapy, who are perceived as being at high-risk.
The subanalysis included the same population as studied SAMMPRIS; transient ischaemic attack, or stroke patients with a 70–99% stenosis of a major intracranial artery who were randomised within 30 days of their qualifying event to aggressive medical therapy alone or aggressive medical therapy plus percutaneous transluminal angioplasty and stenting with the Wingspan stent system (Boston Scientific/Stryker).
Helmi L Lutsep, professor, vice chair, and associate director, Oregon Stroke Center, Oregon Health and Science University, Portland, USA, presented the results at the International Stroke Conference 2012. She said subanalysis results supported the view that the benefit of medical management over stenting was similar in patients whether or not they were receiving antithrombotic therapy at the time of their qualifying event for study enrolment.
The investigators hypothesised that patients who had their qualifying transient ischaemic attack or stroke on antithrombotic therapy (which is considered an antithrombotic failure) in the SAMMPRIS trial have a similar benefit from aggressive medical therapy over percutaneous transluminal angioplasty and stenting compared with patients not on antithrombotic therapy, at the time of their qualifying events.
The researchers randomised 451 patients to either aggressive medical therapy or aggressive medical therapy plus stenting. They were then followed at 30-days after enrolment and over the duration of follow-up. The primary endpoints of the study were stroke or death within 30 days of enrolment or revascularisation or stroke in the treated artery beyond 30 days.
Of the 451 enrolled patients, 286 (63%) had qualifying events on antithrombotic therapy. One hundred and forty five were randomised to the stenting group and 141 to aggressive medical management. The 30-day rates of stroke or death were 15.9% in the stenting arm vs. 4.3% in the medical management arm. The Kaplan-Meier curves are significantly different for these two groups. For the 165 patients who had qualifying events on no antithrombotic therapy, 79 were randomised to stenting and 86 were randomised to medical management. The 30-day rates of stroke or death were 12.7% in the stenting arm and 8.2% in the medical management arm. The Kaplan-Meier curves are not significantly different for these two groups.
Of those receiving an antithrombotic, 95.8% were receiving an antiplatelet, 22.5% were receiving clopidogrel and aspirin, and 1.4% received an anticoagulant at the time of their qualifying event.
“The current SAMMPRIS results indicate that the benefit of aggressive medical therapy is similar in patients on vs. off antithrombotic therapy at the time of their qualifying events, and support the findings from the WASID (warfarin-Aspirin symptomatic intracranial disease) trial that antithrombotic failure does not identify a higher risk subgroup of patients,” said Lutsep.