Objective: To evaluate the comparative safety and efficacy of direct endovascular thrombectomy(dEVT) compared to bridging therapy(BT:IV-tPA+EVT) and assess if BT potential benefit relates to stroke severity, size and initial presentation to EVT vs. non-EVT center.

Methods: In a prospective multicenter cohort-study of imaging selection for endovascular thrombectomy[SELECT], anterior-circulation large vessel occlusion (LVO) patients presenting to EVT-capable centers within 4.5hours from last-known-well were stratified into BT vs. dEVT. The primary outcome was 90-day functional independence[modified Rankin Scale(mRS)=0-2]. Secondary outcomes included a shift across 90-day mRS grades, mortality, symptomatic intracranial hemorrhage. We also performed subgroup-analyses according to initial presentation to EVT-capable center (direct versus transfer), stroke severity and baseline infarct core volume.

Results: We identified 226 LVOs (54%:men, mean age:65.6±14.6years, median NIHSS-score: 17, 28% received dEVT). Median time from arrival to groin-puncture did not differ in BT-patients when presenting directly[dEVT:1.43 (IQR=1.13-1.90) hours vs. BT:1.58(IQR=1.27-2.02)hours,p=0.40] or transferred to EVT-capable centers[dEVT:1.17 (IQR: 0.90-1.48) hours vs. BT:1.27 (IQR: 0.97-1.87) hours,p=0.24]. BT was associated with higher odds of 90-day functional independence (57% vs. 44%,aOR=2.02,95%CI:1.01-4.03,p=0.046) and functional improvement (adjusted cOR=2.06,95%CI:1.18-3.60,p=0.011), and lower likelihood of 90-day mortality (11% vs. 23%,aOR: 0.20,95%CI:0.07-0.58,p=0.003). No differences in any other outcomes were detected. In subgroup-analyses, BT patients with baseline NIHSS-scores<15 had higher functional independence likelihood compared to dEVT (aOR=4.87,95%CI:1.56-15.18,p=0.006); this association was not evident for patients with NIHSS-scores≥15 (aOR=1.05,95%CI:0.40-2.74,p=0.92). Similarly, functional outcomes improvements with BT were detected in patients with core volume strata (Ischemic core <50cc: aOR: 2.10, 95% CI:1.02-4.33, p=0.044 vs ischemic core ≥50cc: aOR: 0.41,95% CI:0.01-16.02,p=0.64) and transfer status (transferred: aOR: 2.21,95% CI:0.93-9.65,p=0.29 vs direct to EVT center: aOR:1.84,95%CI:0.80-4.23,p=0.15). 

Conclusions: Bridging therapy appears to be associated with better clinical outcomes, especially with milder NIHSS-scores, smaller presentation core volumes and those who were “dripped and shipped”.

Classification of Evidence: This study provides Class III evidence that for patients with ischemic stroke from anterior-circulation LVO within 4.5 hours from last-known-well, bridging therapy compared to direct endovascular thrombectomy leads to better 90-day functional outcomes.