Redefining 'success': A systematic review and meta-analysis comparing outcomes between incomplete and complete revascularization

Background: Conventionally, 'successful' endovascular thrombectomy (EVT) had been defined as achieving revascularization of thrombolysis in cerebral infarction (TICI)''2B or greater, rather than as 'complete' (TICI-3) versus 'incomplete' (TICI-2B) revascularization. Purpose: We performed a systematic review and meta-analysis of studies comparing clinical outcomes between patients with TICI-2B and TICI-3 revascularization. Methods: Multiple databases were searched for relevant publications between January 2003 and March 2018. Studies comparing outcomes between the TICI-2B and the TICI-3 group of acute ischemic stroke (AIS) patients treated with EVT were included. Random effects meta-analysis was performed to evaluate outcomes among TICI-2B and TICI-3 groups. The following outcomes were assessed: good neurologic outcome (modified Rankin Scale (mRS)≤2 at day 90), mortality, and intracerebral hemorrhage (ICH). Results: Twenty-one studies comprising 2747 patients were identified. Patients with TICI-2B revascularization had mRS≤2 at day 90 rates of 46% (391/847) compared with 66% (522/791) for TICI-3 patients (OR 0.46, 95% CI 0.37 to 0.57). Mortality rates were significantly higher in the TICI-2B group (78/570, 14%) than in the TICI-3 group (55/709, 8%) (OR 2.00, 95% CI 1.38 to 2.91). The ICH rates were also significantly higher in the TICI-2B group as compared with the TICI-3 group (31% [134/439] vs. 22% [108/490]; OR 2.20, 95% CI 1.47 to 3.30). Conclusions: Differences in all major outcome measures were markedly better in patients with complete versus incomplete but still 'successful' revascularization using prior thresholds, with ORs in the order of those seen in recent definitive trials comparing EVT to an intravenous tissue plasminogen activator.