Acute ischemic stroke patients with large lesion volumes had more favorable outcomes and no greater risk of hemorrhage if they had successful reperfusion with mechanical thrombectomy, a study found.

Researchers used data collected between January 2012 and August 2015 by a prospective clinical registry of consecutive acute ischemic stroke patients receiving mechanical thrombectomy. They focused on patients with large lesions, defined as those with pretreatment diffusion-weighted imaging (DWI)-Alberta Stroke Program Early Computed Tomography Score (ASPECTS) ≤6. All patients had internal carotid artery or middle cerebral artery occlusions. The primary end point was a favorable outcome, defined as a modified Rankin scale score ≤2 at 90 days.

The analysis included 218 patients, of whom 66% had successful reperfusion at the end of mechanical thrombectomy. The successfully reperfused patients had a significantly higher rate of favorable outcomes (38.7% vs. 17.4%; P=0.002) than those without successful reperfusion. They also had lower mortality at three months (22.5% vs. 39.1%; P=0.013). Both groups had similar rates of intracranial hemorrhage (13.0% vs. 14.1%). Results were published by Stroke on Feb. 24.

In the subgroup of patients with particularly large lesions (DWI-ASPECTS <5), favorable outcomes were low and mortality was high, regardless of successful reperfusion (13.0% vs. 9.5% and 45.7% vs 57.1%, respectively). In this group, there was a trend toward better outcomes associated with successful reperfusion, however, the authors noted. They concluded that successful reperfusion is associated with reduced mortality and disability in patients with a score of 5 or 6 and that more data are needed to clarify the potential effects in patients with lower scores.

The findings differ from previous studies, which found increased risks of intracranial hemorrhage and mortality with reperfusion in patients with large strokes, the authors noted. The risk of hemorrhage seems to be associated with initial stroke severity rather than early reperfusion status, according to the study authors, who called for additional research to confirm their conclusion that “large DWI lesion volumes should not preclude patients from reperfusion therapies,” including tissue plasminogen activator and mechanical thrombectomy.