The results of prematurely terminated stenting and aggressive medical management for preventing recurrent stroke in intracranial stenosis (SAMMPRIS) due to excessively high rate of stroke and death in patients randomized to intracranial stent placement is expected to affect the practice of endovascular therapy for intracranial atherosclerotic disease. The purpose of this report is to review the components of the designs and methods SAMMPRIS trial and to describe the influence of those components on the interpretation of trial results.
A critical review of the patient population included in SAMMPRIS is conducted with emphasis on “generalizability of results” and “bias due to cherry picking phenomenon.” The technical aspects of endovascular treatment protocol consisting of intracranial angioplasty and stent placement using the Gateway balloon and Wingspan self-expanding nitinol stent and credentialing criteria of trial interventionalists are reviewed. The influence of each component is estimated based on previous literature including multicenter clinical trials reporting on intracranial angioplasty and stent placement.
The inclusion criteria used in the trial ensured that patients with adverse clinical or angiographic characteristics were excluded. Self-expanding stent as the sole stent, technique of prestent angioplasty, periprocedural antiplatelet treatment, and intraprocedural anticoagulation are unlikely to adversely influence the results of intracranial stent placement. A more permissive policy toward primary angioplasty as an acceptable treatment option may have reduced the overall periprocedural complication rates by providing a safer option in technically challenging lesions. The expected impact of a more rigorous credentialing process on periprocedural stroke and/or death rate following intracranial stent placement in SAMMPRIS such as the one used in carotid revascularization endarterectomy versus stenting trial remains unknown.
The need for developing new and effective treatments for patients with symptomatic intracranial stenosis cannot be undermined. The data support modification but not discontinuation of our approach to intracranial angioplasty and/or stent placement for intracranial stenosis. There are potential patients in whom angioplasty and/or stent placement might be the best approach, and a new trial with appropriate modifications in patient selection and design may be warranted.