Magnetic resonance imaging-based endovascular versus medical stroke treatment for symptom onset up to 12 h.

Background: Recent trials have shown a clear benefit of endovascular therapy for stroke patients presenting within 6 h after stroke onset. Imaging-based selection may identify a cohort with a favorable response to endovascular therapy, in an even later time window.

Aims: We performed an indirect comparison between outcomes seen in DEFUSE 2, a prospective cohort study of patients who received a baseline MRI before endovascular therapy, and a control group from AXIS 2 receiving standard medical care up to 12 h after symptom onset.

Methods: Patients from AXIS 2 with a confirmed large vessel occlusion were selected as a control group for DEFUSE 2-patients. The primary endpoint was good functional outcome at day 90 (Modified Rankin Score 0-2). We performed a stratified analysis based on the presence of the target mismatch for both studies and reperfusion status in DEFUSE 2.

Results: We compared good functional outcome in 108 patients from AXIS 2 and 99 patients from DEFUSE 2. In DEFUSE 2-patients with the target mismatch profile in whom reperfusion was achieved, the rate of good functional outcome was increased compared to target mismatch patients in AXIS 2, 54% versus 29% (OR 3.2, 95% CI 1.1-9.4). In target mismatch patients treated between 6 and 12 h after stroke onset, this association between study and good functional outcome remained present (OR 9.0, 95% CI 1.1-75.8).

Conclusions: This indirect comparison suggests that endovascular treatment resulting in substantial reperfusion is associated with improved outcome in target mismatch patients even beyond 6 h after stroke onset. Confirmation is needed from future clinical trials that randomize patients beyond the 6 h time window.