Takeshi Yoshimoto ^1,2 Hiroshi Yamagami ^1,3,4* Nobuyuki Sakai ⁵ Kazutaka Uchida ⁶ Manabu Shirakawa ⁶ Mikiya Beppu ⁶ Kazunori Toyoda ⁷ Yuji Matsumaru ^1,8 Yasushi Matsumoto ⁹ Kenichi Todo ¹⁰ Mikito Hayakawa ^1,11 Seigo Shindo ¹² MAASAFUMI MORIMOTO ¹³ Masataka Takeuchi ¹⁴ Hirotoshi Imamura ¹⁵ Hiroyuki Ikeda ¹⁶ Kanta Tanaka ^17,7 Hideyuki Ishihara ¹⁸ Hiroto Kakita ⁶ Takanori Sano ^19,20 Hayato Araki ²¹ Tatsufumi Nomura ²² Fumihiro Sakakibara ⁶ Shinichi Yoshimura ⁶

• ¹ Department of Stroke and Cerebrovascular Diseases, University of Tsukuba Hospital, Tsukuba, Japan
• ² Department of Neurology, National Cerebral and Cardiovascular Center (Japan), Suita, Ôsaka, Japan
• ³ Division of Stroke Prevention and Treatment, University of Tsukuba, Tsukuba, Ibaraki, Japan
• ⁴ Department of Stroke Neurology, Osaka National Hospital (NHO), Osaka, Japan
• ⁵ Department of Neurosurgery, Shimizu Hospital, Kyoto, Kyōto, Japan
• ⁶ Department of Neurosurgery, Hyogo Medical University, Kobe, Hyōgo, Japan
• ⁷ Department of Cerebrovascular Medicine, National Cerebral and Cardiovascular Center (Japan), Suita, Ôsaka, Japan
• ⁸ Department of Neurosurgery, University of Tsukuba, Tsukuba, Ibaraki, Japan
• ⁹ Division of Development and Discovery of Interventional Therapy, Tohoku University Hospital, Sendai, Japan
• ¹⁰ Stroke Center, Osaka University Graduate School of Medicine, Suita, Miyagi, Japan
• ¹¹ Department of Neurology, University of Tsukuba, Tsukuba, Ibaraki, Japan
• ¹² Department of Neurology, Japanese Red Cross Kumamoto Hospital, Kumamoto, Kumamoto, Japan
• ¹³ Department of Neurosurgery, Yokohamashintoshi Neurosurgical Hospital, Yokohama, Kanagawa, Japan
• ¹⁴ Department of Neurosurgery, Seisho Hospital, Odawara, Kanagawa, Japan
• ¹⁵ Department of Neurosurgery, National Cerebral and Cardiovascular Center (Japan), Suita, Ôsaka, Japan
• ¹⁶ Department of Neurosurgery, Kurashiki Central Hospital, Kurashiki, Okayama, Japan
• ¹⁷ Stroke Center, Kindai University Hospital, Osakasayama, Osaka, Japan
• ¹⁸ Department of Neurosurgery, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi, Japan
• ¹⁹ Department of Neurosurgery, Ise Red Cross Hospital, Ise, Mie, Japan
• ²⁰ Department of Neurosurgery, Mie Prefectural Mental Medical Center, Tsu, Mie, Japan
• ²¹ Department of Neurosurgery, Araki Neurosurgical Hospital, Hiroshima, Hiroshima, Japan
• ²² Department of Neurosurgery, Ohkawara Neurosurgical Hospital, Muroran, Hokkaidō, Japan

We aimed to clarify the association between intraoperative P2Y12 inhibitor administration during EVT and clinical outcomes in patients with anterior circulation TO stroke.Methods: Among consecutive patients with acute ischemic stroke (AIS) enrolled in the Recovery by Endovascular Salvage for Cerebral Ultra-acute Embolic and Atherothrombotic Stroke with Large Vessel Occlusion Registry from 2016 to 2019, those with anterior circulation TOs who underwent EVT were analyzed. These patients were categorized into the following groups: those who received P2Y12 inhibitors during the perioperative period and those who did not receive P2Y12 inhibitors. The outcomes included good functional outcomes, as indicated by a modified Rankin Scale score of 0-2 at 90 days, and the incidence of symptomatic intracranial hemorrhage (SICH) was compared between the two groups. Multivariate logistic regression models were used to assess the association of outcomes with perioperative P2Y12 inhibitor administration. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using the group that did not receive P2Y12 inhibitors as the reference. The perioperative period included the period in which antithrombotic therapy was administered immediately before EVT and during the operative period.We enrolled 242 patients with AIS with anterior circulation TOs (42 females [17.4%]; median age, 76 [interquartile range, 69-81] years). Patients who received P2Y12 inhibitors during the perioperative period (n=131) showed a higher frequency of carotid artery stenting than those who did not receive perioperative P2Y12 inhibitors (n=111) (86.3% vs. 42.3%, P < 0.01). Furthermore, patients who received perioperative P2Y12 inhibitors during the perioperative period had a higher incidence of good functional outcomes than those who did not receive perioperative P2Y12 inhibitors (42.0% vs. 32.4%; adjusted OR: 6.65, 95% CI: 1.88-23.53), with no significant differences between the groups in the incidence of SICH (5.3% vs. 8.1%; OR: 0.44; 95% CI: 0.09-2.09).Perioperative administration of P2Y12 inhibitors may be associated with a higher frequency of good functional outcomes in patients undergoing EVT for AIS with anterior circulation TOs. However, since several confounding factors are involved in this sub-analysis of EVT for anterior circulation TOs, further studies are warranted.