O-004 the first pass effect: a new measure for stroke thrombectomy devices (2015)

<h3>Background</h3> Advances in acute ischemic stroke mechanical thrombectomy devices have led to increased expectations of their safety and efficacy results. <h3>Objective</h3> To describe a new measure for the newer generation stroke thrombectomy devices, the First Pass Effect (FPE), defined as achieving thrombolysis in cerebral ischemia (TICI) score of 3 from the first pass, without the use of rescue therapy. In addition, a second objective was to assess if achieving TICI2b only with FP (FPE-TICI2b only) yielded similar results as FPE-TICI3 or non-FPE-TICI3 or non-FPE-TICI2b. The influence of FPE on clinical outcome, and its frequency and predictors was evaluated in the North American Solitaire Acute stroke (NASA) registry. <h3>Methods</h3> The FPE group was identified from the NASA multicenter registry database. Baseline features and clinical outcomeswere compared between the FPE group and the rest of the cohort. Subsequently, two multivariate analyzes were performed to identify if FPE is an independent predictor of clinical outcome and to identify the predictors of FPE. Furthermore, we assessed the difference between FPE and achieving other revascularization grades such as non-FPE-TICI3, FPE-TICI2b, and non-FPE-TICI2b scores. Clinical outcomes were mRS0–2 at 90 days, NIH stroke severity scale, mortality, and symptomatic intracranial hemorrhage (sICH). <h3>Results</h3> A total of 354 patients from 24 US centers were included in the NASA registry. The FPE was achieved in 89/354 (25.1%). Baseline demographics were comparable between FPE and the rest of the cohort, except that the FPE population had less octogenarians (34.6% vs. 65.4%), more woman (60.7% vs. 47.2%), and more Caucasians (83% vs. 71.2%). Baseline NIHSS and time from onset to groin puncture did not differ among the two groups. Angiographic features demonstrated more MCA occlusion (64% vs. 52.7%) and less ICA occlusion (10.1% vs. 27.7%) in the FPE group. Technical factors associated with FPE were limited to BGC use (64.8% vs. 36.8%), with no difference with use of IV-tPA, IA-tPA, or General Anesthesia. Multivariate analysis demonstrated use of BGC, no ICA occlusion, MCA occlusion, female gender, and white race as independent  predictors of FPE. Clinical outcome measured with mRS 0–2 at 90 days was seen in 61.3%, 52.4%, 44.7%, and 39.1% with FPE-TICI3, FPE-TICI 2b, non-FPE-TICI3, and non-FPE-TICI2b, respectively. sICH was seen less frequently in FPE (5.6%,11.6%, 9.6%, and 12.9% in FPE-TICI3, FPE-TICI2b, non-FPE-TICI3,and non-FPE-TICI2b, respectively). Ninety days mortality was 16.3%, 31.0%, 27.7%, and 29.7% with FPE-TICI3, FPE-TICI2b, non-FPE-TICI3, and non-FPE-TICI2b, respectively. <h3>Conclusions</h3> The First Pass Effect was seen in 25.1% of NASA post-marketing registry patients and is the most powerful predictor of clinical outcome with best safety results. FPE is more commonly seen in white patients, MCA occlusion, and balloon guide catheter use; however, ICA terminus occlusion seems to be resistant to FPE. The FPE may also be related to gender, race, and age. Further research is needed to better understand the FPE and to guide future technical advances. <h3>Disclosures</h3> O. Zaidat: 1; C; Covidien, Stryker. 2; C; Covidien, Stryker. A. Castonguay: None. R. Gupta: None. C. Sun: None. C. Martin: None. W. Holloway: None. N. Mueller-Kronast: None. J. English: None. I. Linfante: None. G. Dabus: None. T. Malisch: None. F. Marden: None. H. Bozorgchami: None. A. Xavier: None. A. Rai: None. M. Froehler: None. A. Badruddin: None. T. Nguyen: None. M. Taqi: None. M. Abraham: None. V. Janardhan: None. H. Shaltoni: None. R. Novakovic: None. A. Yoo: None. A. Abou-Chebl: None. P. Chen: None. G. Britz: None. R. Kaushal: None. A. Nanda: None. R. Nogueira: None.