Objective To investigate the influencing factors for acute multiple vessels occlusion(MVO)and its impact on the prognosis of patients with anterior circulation acute large vessel occlusion stroke(ALVOS)who achieved successful recanalization after endovascular treatment(EVT).Methods Patients with anterior circulation ALVOS who received successful EVT at the Yijishan Hospital of Wannan Medical College between July 2015 and April 2023 were retrospectively analyzed.Baseline data,including age,sex,onset-to-puncture time(OTP),onset-to-recanalization time(OTR),medical history(including atrial fibrillation,diabetes,hypertension),alcohol and smoking history,admission blood pressure(systolic and diastolic),Alberta stroke program early CT score(ASPECTS),National Institutes of Health stroke scale(NIHSS)score,trial of Org 10172 in acute stroke treatment(TOAST)classification(atherosclerotic type,cardioembolic type,and other etiology types),and 90-day modified Rankin scale(mRS)score were collected.Collateral circulation was assessed based on the degree of contrast agent reflux observed in the occluded arterial supply area during delayed DSA,and patients were classified into poor and good collateral circulation groups.Malignant cerebral edema was defined as a midline shift of ≥5 mm on the follow-up CT scan performed on day 3 post-surgery.The primary endpoint(efficacy indicator)was the 90-day mRS score,with mRS score≤ 2 considered as a good prognosis and mRS score＞2 considered as a poor prognosis.The secondary endpoint(safety indicator)was the 90-day mortality rate.All patients were divided into MVO and non-MVO groups based on whether they had single or multiple intracranial vessel occlusions.Acute MVO was defined as the detection of acute occlusion of other large or medium vessels,in addition to the main vessels(internal carotid artery or M1/M2 segments of the middle crebral artery[MCA]),in CT angiography,MR angiography,or DSA,resulting in ischemia in brain regions distinct from the main occlusion area.Factors that showed statistically significant differences in univariate analysis were further analyzed using multivariate Logistic regression to identify the risk factors for the occurrence of acute MVO and the factors associated with the prognosis of ALVOS patients.Results A total of 846 patients with ALVOS were included,with ages ranging from 26 to 94 years(mean age[69±11]years).The proportion of male patients was 57.2％(484/846).The median admission ASPECTS was 8(7,9)and the median admission NIHSS score was 14(12,18).The incidence of malignant cerebral edema at 3 days post-surgery was 13.4％(112/835),and the 90-day mortality rate was 19.1％(162/846).(1)Among the 846 ALVOS patients,810(95.7％)were in the non-MVO group and 36(4.3％)were in the MVO group.Univariate analysis showed significant differences between the MVO and non-MVO groups in terms of atrial fibrillation,malignant cerebral edema,admission ASPECTS,admission NIHSS scores,TOAST classification,collateral circulation,rate of complete recanalization,and 90-day poor prognosis rate(all P＜0.05).However,there was no statistically significant difference in 90-day mortality between the two groups(P=0.193).Multivariate Logistic regression analysis showed that TOAST classification of cardioembolic type(OR,16.089,95％CI 1.835-141.061,P=0.012)and other etiology types(OR,9.768,95％CI 1.078-88.540,P=0.043)were associated with the occurrence of MVO.(2)Among the 846 ALVOS patients,445 had a good prognosis at 90days,and 401 had a poor prognosis.Univariate analysis showed that,compared to the good prognosis group,the poor prognosis group had a lower proportion of males and smokers,and a higher proportion of patients with older age,higher baseline systolic blood pressure,hypertension,diabetes,and atrial fibrillation(all P＜0.01).Additionally,the poor prognosis group had higher admission NIHSS scores(P＜0.01),lower admission ASPECTS,lower rates of good collateral circulation and complete recanalization,higher rates of malignant cerebral edema and MVO,and statistically significant differences in TOAST classification distribution(all P＜0.01).Multivariate Logistic regression analysis showed that MVO was associated with poor 90-day prognosis in ALVOS patients after EVT(OR,3.368,95％CI 1.149-9.878,P=0.027).Furthermore,older age(OR,1.045,95％CI 1.025-1.066),diabetes(OR,1.719,95％CI 1.080-2.734),higher baseline systolic blood pressure(OR,1.012,95％CI 1.004-1.019),lower admission ASPECTS(OR,0.746,95％CI 0.674-0.826),higher admission NIHSS score(OR,1.115,95％CI 1.070-1.162),without immediate postoperative complete recanalization(OR,0.413,95％CI 0.290-0.592),poor collateral circulation(OR,0.594,95％CI 0.415-0.851),and malignant cerebral edema(OR,6.191,95％CI 3.026-12.670)were all associated with poor 90-day prognosis after EVT in ALVOS patients(all P＜0.05).Conclusions The TOAST classification of cardioembolic type and other etiology types is associated with MVO.MVO is a risk factor for poor outcomes after successful EVT in ALVOS patients.