Intra-arterial thrombolysis within three hours of stroke onset in middle cerebral artery strokes

The Prolyse in Acute Cerebral Thromboembolism II (PROACT II) trial showed improved outcomes in patients with proximal middle cerebral artery (MCA) occlusions treated with intra-arterial (IA) thrombolysis within 6 h of stroke onset. We analyzed outcomes of patients with proximal MCA occlusions treated within 3 h of stroke onset in order to determine the influence of time-to-treatment on clinical and angiographic outcomes in patients receiving IA thrombolysis.

Thirty-five patients from three academic institutions with angiographically demonstrated proximal MCA occlusions were treated with IA thrombolytics within 3 h of stroke onset. Outcome measures included outcomes at 30-90 day follow-up, recanalization rates, incidence of symptomatic intracranial hemorrhage, and mortality in the first 90 days. The endpoints were compared to the IA treated and control groups of the PROACT II trial.

The median admission National Institutes of Health Stroke Scale (NIHSS) score was 16 (range 4-24). The mean time to initiation of treatment was 106 min (range 10-180 min). Sixty-six percent of patients treated, had a modified Rankin Scale (mRS) score of 2 or less at 1-3 month follow-up compared to 40% in the PROACT II trial. The recanalization rate was 77% (versus 66% in PROACT II). The symptomatic intracranial hemorrhage rate was 11% (versus 10% in PROACT II) and the mortality rate was 23% (versus 25% in PROACT II).

Time-to-treatment is just as important in IA thrombolysis as it is in IV thrombolysis, both for improving clinical outcomes and recanalization rates as well.