Mechanical Thrombectomy for Acute Stroke: Early versus Late Time Window Outcomes

Background and purpose: Recent trials have shown benefit of thrombectomy in patients selected by penumbral imaging in the late (>6 hours) window. However, the role penumbral imaging is not clear in the early (0-6 hours) window. We sought to evaluate if time to treatment modifies the effect of endovascular reperfusion in stroke patients with evidence of salvageable tissue on CT perfusion (CTP).

Methods: We retrospectively analyzed consecutive patients who underwent thrombectomy in a single center. Demographics, comorbidities, National Institute of Health Stroke Scale (NIHSS), rtPA administration, ASPECTS, core infarct volume, onset to skin puncture time, recanalization (mTICI IIb/III), final infarct volume were compared between patients with good and poor 90-day outcomes (mRS 0-2 vs. 3-6). Multivariable logistic regression analyses were used to identify independent predictors of a good (mRS 0-2) 90-day outcome.

Results: A total of 235 patients were studied, out of which 52.3% were female. Univariate analysis showed that the groups (early vs. late) were balanced for age (P = .23), NIHSS (P = .63), vessel occlusion location (P = .78), initial core infarct volume (P = .15), and recanalization (mTICI IIb/III) rates (P = .22). Favorable outcome (mRS 0-2) at 90 days (P = .30) were similar. There was a significant difference in final infarct volume (P = .04). Shift analysis did not reveal any significant difference in 90-day outcome (P = .14). After adjustment; age (P < .001), NIHSS (P = .01), recanalization (P = .008), and final infarct volume (P < .001) were predictive of favorable outcome.

Conclusions: Penumbral imaging-based selection of patients for thrombectomy is effective regardless of onset time and yields similar functional outcomes in early and late window patients.