Endovascular Treatment of Acute Ischemic Stroke May Be Safely Performed With No Time Window Limit in Appropriately Selected Patients

Background and Purpose-The traditional time window for acute ischemic stroke intra-arterial therapy (IAT) is <6 hours, which is based on pharmacological thrombolysis without penumbral imaging. This study was conducted to determine the safety of patient selection for IAT based on perfusion mismatch rather than time. Methods-A cohort of consecutive patients treated with IAT was identified by database review. Patients were selected for IAT based on the presence of perfusion mismatch using CT perfusion or MRI regardless of stroke duration. Thrombolytics were minimized after 6 hours in favor of mechanical embolectomy or angioplasty +/- stenting. Outcomes (National Institutes of Health Stroke Scale, modified Rankin Scale) were assessed by independent examiners. A multivariate analysis was performed to compare those treated <6 hours (early) with those treated >6 hours (late). Results-Fifty-five patients (mean National Institutes of Health Stroke Scale=19.7 +/- 5.7) were treated, 34 early and 21 late, with mean time-to-intervention of 3.4 +/- 1.6 hours and 18.6 +/- 16.0 hours, respectively. Thrombolysis In Myocardial Ischemia 2 or 3 recanalization was achieved in 82.8% early and 85.7% late patients (P=1.0). Intracerebral hemorrhage occurred in 25.5% overall, but symptomatic intracerebral hemorrhage occurred in 8.8% of the early and 9.5% of the late patients (P=1.0). Thirty-day mortality was similar (29.4% versus 23.8%, P=0.650). At 3 months, 41.2% and 42.9%, respectively, achieved a modified Rankin Scale <= 2 (P=0.902). Only presenting National Institutes of Health Stroke Scale was a predictor of modified Rankin Scale <= 2 (OR 0.794[95% CI 0.68 to 0.92], P=0.009) and death (adjusted OR 1.29[95% CI 1.04 to 1.59], P=0.019). Conclusions-In appropriately selected patients, IAT for acute ischemic stroke can be performed safely regardless of stroke duration. The concept of an acute ischemic stroke treatment window for IAT should be re-evaluated with a clinical trial selecting patients with perfusion mismatch. (Stroke. 2010; 41:1996-2000.)