Abstract 3314: The Role of Bridging with Intravenous Thrombolysis in Endovascular Therapy of Acute Ischemic Stroke.
Authors: Kass-Hout Omar , Kass-Hout Tareq , Mokin Maxim , Orion David , Jahshan Shadi , Yashar Perham , Levy Elad , Siddiqui Adnan , Snyder Kenneth 
Published: July 2021

Background:
Large vessel occlusions with a high clot burden are less likely to improve with the FDA-approved IV strategy. Endovascular therapy within the first 3 h of stroke symptom onset provides an effective alternative treatment in patients with large vessel occlusion. It is not clear if combination of IV thrombolysis and endovascular approach is superior to endovascular treatment alone.

Methods:
We retrospectively reviewed all cases of acute ischemic stroke with large vessel occlusion treated within the first 3 h stroke onset during the 2005-2010 period. First group received endovascular therapy within the first 3 h of stroke onset. Second group consisted of patients who received IV thrombolysis within the first 3 h followed by endovascular therapy. We compared the following outcomes: revascularization rates, NIHSS score at discharge, mRS at discharge and 3months, symptomatic hemorrhage rates and mortality.

Results:
Among 104 patients identified, 42 received combined therapy, and 62 received endovascular therapy only. The two groups had similar demographic (age and sex distribution) and vascular risk factors distribution, as well as NIHSS score on admission (14.8±4.7 and 16.0±5.3; p=0.23). We found no difference in TIMI recanalization rates (Thrombolysis in Myocardial Infarction scale score of 2 or 3) following combined or endovascular therapy alone (83.3% and 79.0%; p=0.59). A preferred outcome, defined as a mRS of 2 or less at 90 days also did not differ between the combined therapy group and the endovascular only group (37.5% and 34.5%; p=0.76). There was no difference in mortality rate (22.5% and 31.0%; p=0.36) and the rate of symptomatic intracranial hemorrhage (9.5% and 8.1%; p=0.73). There was a significant difference in mean time from symptom onset to endovascular treatment between the combined group (227±88 min) and endovascular only group (125±40 min; p<0.0001).Patients with good TIMI recanalization rate of 2 or 3 showed a trend of having a better mRS at 90 days in both bridging (16.67% vs. 41.18%, p-value: 0.3813) and endovascular groups (25% vs. 34.78%, p-value: 0.7326).When analyzing the correlation of mRS at 90 days with the site of occlusion, patients in the bridging group showed a trend of a better outcome when the site of occlusion was ICA (33.3% vs 30%) and MCA (66.67% vs. 27.59%) and worse outcome when the site of occlusion was in the posterior circulation (26.32% vs. 50%), however, these results were not statistically significant (p-values: 0.1735& 0.5366).

Conclusion:
Combining IV thrombolysis and endovascular therapy achieves similar rates of clinical outcomes, revascularization rates, complications and mortality rates, when compared with endovascular treatment alone. The combined therapy, however, significantly delays initiation of endovascular treatment. A randomized prospective trial comparing both treatment strategies in acute ischemic stroke is warranted