Objective: Endovascular therapy (EVT) within 6 hours from ischemic stroke onset were recommended by 2015 AHA/ASA guideline. Effectiveness and factors for favorable outcome for EVT beyond 6 hours are unclear. We investigated whether onset to puncture time (O2P) beyond 6 hours is associated with outcome at 3 months and what is the favorable factors in patients treated with EVT beyond 6 hours.
Methods: We performed a retrospective, single center analysis of patients with acute ischemic stroke who underwent EVT. The O2P, risk factors, reperfusion success rate and outcome at 3 month were assessed. First, all patients were classified into the two groups with EVT beyond 6 hours or not. Second, we compared any characteristics and favorable outcome between two groups. Finally, we investigated independent factors for favorable outcome in patients treated with EVT beyond 6 hours. Favorable outcome and good reperfusion were defined by modified Rankin scale ≤ 2 and thrombolysis in cerebral infarction (TICI) score ≥ 2B, respectively.
Results: Of the 130 EVT cases, 124 cases with known onset time were enrolled (age; 75 [66-83] and 74 (60.5%) men). 98 (79%) were treated with EVT within 6 hours and 26 (21%) patients were beyond 6 hours. Absence of atrial fibrillation (11[42%] vs. 70[71%], p=0.01), high DWI-ASPECTS (9 [7-10] vs. 7 [6-9], p=0.01), no use of intravenous tissue plasminogen (1[4%] vs. 50[51%], p<0.01) and low achievement of good reperfusion (14[54%] vs. 77[79%], p=0.01) were more frequently observed in beyond 6 hours group than within 6 hours group. However, favorable outcome was not different between two groups (beyond 6 hours group ;10(38%) vs. within 6 hours group; 43(44%), p = 0.66). In beyond 6 hours group, good reperfusion (9[90%] vs. 5[31%], p=0.01) and presence of hyperlipidemia (7[70%] vs. 3, p=0.02) were associated with favorable outcome. On multivariate analysis, only good reperfusion (OR 45.6, 95%CI 3.7-2271.4, p<0.01) was the independent factor associated with favorable outcome.
Conclusions: The frequency of favorable outcome in beyond 6 hours group was not lower than within 6 hours group. Good reperfusion can improve patient outcome in O2P within 6 hours as well as beyond 6 hours.