Outcomes of mechanical thrombectomy with pre-intravenous thrombolysis: a systematic review and meta-analysis

Background and purpose Whether pre-intravenous thrombolysis (IVT) provides any extra benefits to mechanical thrombectomy (MT) remains controversial. We conducted a systematic review and meta-analysis to compare MT with pre-IVT (IVT + MT) and MT without pre-IVT (MT) for acute ischemic stroke of large vessel occlusion. Methods We systematically searched PubMed, EMBASE and Cochrane Library to identify studies comparing outcomes between IVT + MT and MT from inception to Jan 24, 2019. Random effects mode was used to pool relative risk (RR) with confidence intervals (CI) to compare functional independence in terms of modified Rankin Scale (mRS) 0-2, favorable outcome (mRS 0-1) and mortality at three-months, symptomatic intracerebral hemorrhage, successful reperfusion, and complete reperfusion between the two treatments groups. Results We included 30 studies enrolling 8970 patients with acute ischemic stroke of large vessel occlusion. Compared with MT, IVT + MT significantly increased the rate of 3-month functional independence (RR 1.20, 95% CI 1.12-1.30; P < 0.0001) and favorable outcome (RR 1.28; 95% CI 1.16-1.40; P < 0.0001), increased the rate of successful reperfusion (RR 1.04,95% CI 1.01-1.08; P = 0.013) and complete reperfusion (RR 1.10; 95% CI 1.01-1.19; P = 0.024), reduced the rate of mortality (RR 0.74, 95% CI 0.67-0.82; P < 0.0001), without significantly increasing the rate of symptomatic intracerebral hemorrhage (RR 0.98,95% CI 0.82-1.17; P = 0.833). The results remained stable in sensitivity analyses and adjusting for publication bias. Conclusions Pre-IVT provides extra benefits to MT on clinical and imaging outcomes without increasing symptomatic intracerebral hemorrhage in acute ischemic stroke of large vessel occlusion.