Neuroradiological interventions in cerebrovascular disease: Intracranial revascularization

Introduction Intracranial atherosclerotic disease (ICAD), the most common cause of stroke worldwide (1), is characterized by progressive involvement of the major intracranial arteries and is associated with a high risk of new and recurrent strokes (2). In particular, patients with a history of recent transient ischemic attack or stroke and a significant intracranial stenosis (70-99%) have been shown to be prone to recurrent stroke despite treatment with aspirin and management of their vascular risk factors (3). The use of percutaneous angioplasty, with and without stent placement, has been proposed in this patient population as an effort to decrease the incidence of new ischemic events and improve outcomes. Angioplasty alone has a technical success rate of over 80% (4-7). When performed on an elective basis, complication rates as low as 4-6% have been observed (4,8), leading some practitioners to advocate the use of angioplasty only. However, angioplasty followed by stent placement is usually preferred, as it overcomes some of the limitations of angioplasty alone, including immediate elastic recoil, dissection, acute vessel closure, and residual stenosis. Both balloon-expandable and self-expanding stents have been used, with a technical success rate exceeding 90% (9-13). The Stenting versus Aggressive Medical Therapy for Intracranial Arterial Stenosis (SAMMPRIS) trial (13) was the first randomized, prospective trial to compare endovascular treatment with the Wingspan stent system (Boston Scientific, Natick, MA) with best medical management. Enrollment in the trial was stopped after 451 patients because of a stroke or death rate of 14.7% in the stenting group versus 5.8% in the medical management group. The surprising findings in this study were that the risk of stroke with medical management was lower than expected, while the risk of PTAS with the Wingspan system was higher than expected. The principal message of the SAMMPRIS study is that intracranial stenting cannot be considered as the first line therapy of ICAD at this time. However, two important points must be remembered: 1) the SAMMPRIS study investigated a single device (the Wingspan system), and 2) intracranial stenting remains an important tool for patients with ICAD failing optimal medical therapy.