Mechanical Thrombectomy vs Bridging Therapy for Anterior Circulation Large Vessel Occlusion Stroke: Systematic Review...

Current guidelines recommend the use of mechanical thrombectomy (MT) plus IV thrombolysis (aka bridging therapy [BT]) for patients with anterior circulation large vessel occlusion (LVO) stroke. However, clinical equipoise exists in relation to the use of BT vs MT alone. Our objective is to compare the efficacy and safety of BT and MT for anterior circulation LVO.

A systematic search of biomedical literature databases was performed from inception to October 29, 2021, to identify prospective and retrospective studies comparing the rates for functional independence (modified Rankin Scale score 0-2) and mortality at 90 days, symptomatic intracranial hemorrhage (sICH), and successful recanalization rates for MT and BT. Effect size was represented by odds ratio (OR), and analysis was done with random-effects meta-analysis. Heterogeneity was assessed by I ² and Cochrane Q statistics.

Overall, 41 studies with 14,885 patients were included. Mean ± SD age was 69 ± 11 years for BT and 70 ± 11 years for MT. All studies used alteplase as the thrombolytic agent. The BT group had 29% higher odds for functional independence (OR 1.29, 95% CI 1.16-1.44, I ² = 42%), 25% higher odds of successful reperfusion (OR 1.25, 95% CI 1.08-1.44, I = 42%), and 31% decrease in odds for mortality (OR 0.69, 95% CI 0.60-0.80, I ² = 47%) compared with MT. sICH prevalence was similar between groups (OR 1.10, 95% CI 0.95-1.28, I ² = 0%). Six of the studies were randomized controlled trials (RCTs) with intention-to-treat analysis done in patients presenting directly to MT-capable centers. When analysis was restricted to these 6 RCTs (n = 2,333), no differences were observed in functional independence (OR 1.08, 95% CI 0.91-1.27, I ² = 0%), sICH (OR 1.37, 95% CI 0.95-1.97, I ² = 0%), or mortality (OR 0.93, 95% CI 0.74-1.16, I ² = 0%) between groups. However, successful reperfusion favored the BT group (OR 1.35, 95% CI 1.06-1.73, I ² = 0%).

The odds for functional independence, successful reperfusion, and mortality for the entire dataset favored the use of BT over MT (medium heterogeneity and low quality of evidence). When analysis was restricted to RCTs, both treatments had similar functional and safety outcomes (no heterogeneity), but recanalization rates favored the BT group (no heterogeneity). Because these findings may differ in patients who present to non-MT-capable centers or with the use of other thrombolytic agents, further RCTs are needed.