Abstract DP303: Effect of IAT plus MT versus MT alone on excellent functional outcome (mRS 0-1) at 90 days

Background: After a successful mechanical thrombectomy (MT), acute ischemic stroke (AIS) due to large vessel occlusion (LVO) often experience a “recanalization -outcome gap” due to factors such as distal embolus obstruction and microcirculation hypoperfusion. Adjunctive intra-arterial thrombolysis (IAT) is performed to enhance microvascular reperfusion. However, the overall clinical advantage remains uncertain. Methods: We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing IAT + MT versus MT alone in adult AIS patients after MT. We searched PubMed, Embase, and Cochrane Central from inception to July 2025, following the PRISMA approach and a protocol registered in PROSPERO. The primary endpoint was excellent functional outcome (modified Rankin scale [mRS] 0-1 at 90 days). Secondary outcomes include good functional outcome (mRS 0-2), all-cause mortality, any intracranial hemorrhage (ICH), and symptomatic ICH (sICH). Subgroup analyses were conducted based on the type of thrombolytic agent used and the severity of stroke. Results: Seven RCTs (n = 4,017) met inclusion criteria. IAT + MT significantly increased the likelihood of achieving the excellent functional outcome (RR = 1.23, 95% CI 1.11 – 1.36), with consistent benefit for tenecteplase and alteplase, and among the individuals with varying stroke severity. There was no significant effect on good functional outcome (RR = 1.06, 95% CI 0.98 – 1.15), mortality (RR = 0.98, 95% CI 0.82 – 1.18), or sICH (RR = 1.14, 95% CI 0.76 – 1.70). Any ICH risk showed a non-significant trend (RR = 1.16, 95% CI 0.98 – 1.37), reaching significance in sensitivity analysis by excluding a trial with a low baseline ASPECTS score (RR = 1.21, 95% CI 1.03 – 1.42). Conclusion: Outcomes suggest that adjunctive IAT after MT improves the likelihood of complete functional recovery without increasing mortality or symptomatic hemorrhage, although there is a slight increase in total ICH risk that might be noted. Additional risk-benefit analysis is necessary for the refinement of candidate, agent, and dose selection.