Medical Therapy Beats Intracranial Stenting Even Over the Long Term

Given the historical inadequacy of medical therapy for symptomatic intracranial atherosclerosis, researchers conducting the SAMMPRIS trial (NEJM JW Neurol Sep 20 2011) enrolled 451 patients with recently symptomatic 70% to 99% stenosis and randomly assigned them to receive aggressive medical therapy with or without intracranial stenting. The trial was stopped early in 2011 because the intervention group experienced significantly more strokes, mostly in the immediate periprocedural period. The original study report covered <1 year of follow-up, arousing concern that the medical therapy group would experience more strokes over the long term, thus offsetting the early harm from stenting. In response, the SAMMPRIS investigators have now published updated results with a minimum of 24 months of follow-up in all patients.

Over a median 32.4 months of follow-up, the medical therapy group had a significantly lower cumulative rate of the primary outcome (14.1% versus 20.6% at the 2-year mark) and of any stroke (17.2% versus 23.3% at the 2-year mark). The early divergence in outcome rates did not narrow over time; the difference in absolute risk for the primary endpoint between groups was 8.9% at 30 days and 9.0% at 3 years. A worst-case scenario analysis assuming that all patients lost to follow-up in the medical arm had a stroke, compared with none in the intervention arm, still indicated no benefit from intracranial stenting. Several subgroup analyses failed to identify any set of patients who benefited from stenting, including patients with multiple infarcts while already on antithrombotic therapy.