Abstract TP44: First Pass Effect in Mechanical Thrombectomy for Emergent Large Vessel Occlusion Outside Clinical Trials: Combined Report From a University and a Community Hospital

Abstract

Background: First pass effect (FPE) is defined as achieving a TICI 3 recanalization with a single pass with no use of rescue therapy. We aimed to compare the clinical and radiological outcomes of patient who had FPE versus those who didn’t outside a clinical trial or registry in a community setting. Methods: Patients were identified from two prospectively collected stroke databases from Jan 2015 to March 2018. We compared clinical and radiological outcomes of all endovascular treated who had FPE to those who didn’t. Primary outcomes were favorable functional outcome at hospital discharge (modified Rankin Scale (mRS) score of 0-3), and the rate of intracranial hemorrhage (ICH). Early neurological improvement, angiographic recanalization, time to recanalization, and mortality at 30 days were used as secondary outcomes. Results: We identified 238 patients who underwent thrombectomy [mean age 68 ± 14 years, 121 (51%) were women]. FPE was achieved in 91(38%) patients. More middle cerebral artery occlusions (59% versus 41%) were present in the FPE group. Mean time from symptoms onset to revascularization was significantly shorter in the FPE group (336 ± 288 minutes vs 438± 364 minutes; P=0.003). Since the general protocol of both institutions was to use ADAPT technique for the first thrombectomy attempt when feasible, 75% of the cases with first pass success were performed with aspiration alone. FPE was an independent predictor of good clinical outcome (mRS score ≤3 56 % in FPE versus 35 % in non-FPE cohort; P=2.601 [odds ratio 2.60 (95% confidence interval 1.25-4.99)]. Similarly lower rate of ICH was observed among FPE group (23% versus 46%; P= 0.40 [(odds ratio 0.4 (95% confidence interval 0.20 -0.79)]. Conclusion: In this analysis from a community setting outside of clinical trials or registries, FPE was associated with significantly improved functional outcomes and lower ICH rates and was more frequently achieved in MCA occlusions. More studies are required in order to determine the most efficient technique to achieve FPE.