Abstract TP42: First Pass Rates Differ Between Anterior and Posterior Circulation During Mechanical Thrombectomy for Emergent Large Vessel Occlusions

Abstract

Background: Patients with vertebrobasilar occlusion were excluded from all major mechanical thrombectomy trials, therefore the evidence regarding the effectiveness of mechanical thrombectomy devices in these patients is limited. First pass effect (FPE) is defined as achieving a TICI 3 recanalization with a single device pass with no use of rescue therapy. We aimed to compare the FPE rates of existing mechanical devices between anterior circulation and vertebrobasilar occlusion and their clinical outcomes from a pooled data of two institutions outside of clinical trial or registry. Methods: Patients were identified from 2 prospectively collected stroke databases from Jan 2015 to March 2018. We compared the FPE rates between anterior circulation and vertebrobasilar occlusions. Other clinical outcomes were favorable functional outcome at hospital discharge (modified Rankin Scale (mRS) score of 0-3), and the rate of intracranial hemorrhage (ICH). Results: A total of 245 patients who underwent thrombectomy were identified. FPE was achieved in total of 97(39.5 %)patients [mean age 68.8 ± 14.1 years, 51 (52.6%) were women]. Overall, 79 (37.2%) of anterior circulation patients had FPE versus 18 (54.5% )with vertebrobasilar occlusions ( p-value<0.001) Since the general protocol was to use ADAPT technique for the first thrombectomy attempt, FPE was achieved in 57(72.2 %) of the cases in the anterior circulation occlusions versus 12 (66.6%) in posterior circulation with aspiration alone (p-value=0.09]. Mean time from symptoms onset to revascularization was significantly longer in posterior circulation compared to anterior circulation [510 ±581.1 vs 302±175.7 ( P <0.001)]. There was no statically significant difference between the 2 groups in good clinical outcome,mRs 0-3 [55.6% versus 55.7% p-value 0.6]. Similarly rate of ICH 2(11.1%) in vertebrobasilar versus 21(26.6%) in anterior circulation were not statistically different (p-value 0.13) Conclusion: In this analysis, vertebrobasilar occlusions had significantly higher percentage of FPE with current thrombectomy devices compared to anterior circulation large vessel occlusions.However, both groups with FPE have similar good functional outcomes and ICH rates.