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Microsoft Word 3b Tóm t¯t LATS Eng MINISTRY OF EDUCATION AND TRAINING MINISTRY OF HEALTH HANOI MEDICAL UNIVERSITY ======= NGUYEN QUANG ANH EVALUATING THE CHARACTERISTIC OF DIAGNOSTIC IMAGING AND THE R[.]
MINISTRY OF EDUCATION AND TRAINING MINISTRY OF HEALTH THE THESIS HAS BEEN COMPLETED AT HANOI MEDICAL UNIVERSITY ======= HANOI MEDICAL UNIVERSITY Supervisor: Prof Pham Minh Thong Reviewer 1: NGUYEN QUANG ANH Reviewer 2: EVALUATING THE CHARACTERISTIC OF DIAGNOSTIC IMAGING AND THE RESULTS OF MECHANICAL THROMBETOMY IN THE TREATMENT OF ACUTE ISCHEMIC STROKE PATIENTS Reviewer 3: The thesis will be present in front of board of university examiner and Speciality Code : Radiology & Nuclear medicine : 9720111 reviewer level at on ABSTRACT OF DOCTORAL THESIS This thesis can be found at: - National Library - Hanoi Medical University Library HA NOI - 2023 LIST OF PUBLISHED ARTICLES CONCERNING THE THESIS Nguyen Quang Anh Effect of mechanical thrombectomy with vs without intravenous thrombolysis in acute ischemic stroke Clin Ter 2022; 173 (3): 257 - 264 Nguyen Quang Anh Results of mechanical thrombectomy in acuted ischemic stroke patients due to large vessel occlusion at Bach Mai hospital: sharing experiences from 227 cases JMR 2022; 154 E10 (6): 28 - 36 INTRODUCTION Cerebral stroke includes hemorrhage and infarction, in which ischemic stroke accounts for 80-87% of cases The consequences of ischemic stroke, if not detected and treated in time, are severe, leaving a double burden on both families and society Similar to the world, in Vietnam, with the shift of the disease pattern according to the development of modern society, the number of patients with acute ischemic stroke every year tends to increase rapidly while the number of our stroke centers is not enough to meet both quantity and quality With all these reasons, a trial with large sample size in Vietnam to have the overview of imaging characteristics and to analyze the effectiveness of mechanical thrombectomy techniques are needed Therefore, we conduct a study “Evaluating the characteristic of dianostic imaging and the results of mechanical thrombectomy in the treatment of acute ischemic patients”, with two details purposes: Describe CT Scanner and MRI imaging charateristics in patients with acute ischemic stroke due to large vessel occlusion Evaluating effects of mechanical thrombectomy in acute ischemic stroke patient with large vessel occlusion The need of thesis implementation: The number of patients with acute ischemic stroke increased in all hospitals at all levels Timely diagnosis and treatment help to reduce disability rates and improve the patient's chances of recovery and return to a normal life In Vietnam, a lot of studies about this topic were reported in the past years, which have been published both domestic and international journals However, there are still many controversial issues that need to be clarified with a sufficiently large sample size In the diagnosis, CT Scanner is preferred because of its suitability for the patient's urgent situation but the application of multiphase (evaluating collateral circulation) and perfusion imaging (identifying the core, penumbra volume) are still limited In treatment, there have been many trials were conducted and published after the success of randomized controlled trials in 2016 that proved the effect of mechanical thrombectomy treatment Some issues still need to be clarified such as: the role of rt-PA, a different effect between mechanical devices or factors affecting the rate of recanalization and clinical recovery post treatmentn Therefore, conducting a research at a comprehensive stroke center with a large number of patients will help to partially solve some of problems and improve treatment effectiveness in Vietnam Novel contributions of the thesis: - ASPECTS was 7.76 ± 1.20 (median 8) and pc-ASPECTS was 7.55 ± 1.62 (median 8) The highest rate seen in M1 occlusion with 41% of patients The average of collateral score was 3.32 ± 1.44, which seen the most in tandem occlusion group In the perfusion map, the average volume of infarction was 23.5 ± 9.0 cm3, which is smaller in groups with higher ASPECTS (9-10 point) and better collateral score (4-5 point) - Good recanalization (TICI 2b-3) was 84.6% while the rate of successful first-pass was 47.6% The hemorrhagic rate seen in 25.1% of patients but only 3.1% was symptomatic intracranial hemorrhage There was 2.7% of severe complications After months, good clinical recovery (mRS ≥ 2) was 65.2% and the mortality was 12.8% - There was no significant difference seen both in groups of mechanincal devices (stent, aspiration, solumbra) and in kinds of treatment in the first 4.5 hours (thrombectomy alone vs thrombectomy + intravenonus rt-PA) - Procedural time ≤ 60 mins (OR 5,952; 95% CI 2,755 – 12,821, p = 0,000) was an independent predictor to the successful recanalization (TICI 2b-3) Age < 80 (OR 3,842; 95% CI 1,764 – 8,365; p = 0,011), NIHSS baseline < 18 (OR 4,917; 95% CI 2,524 – 9,580; p = 0,000), good collateral (OR 15,047; 95% CI 7,181 – 31,529; p = 0,000) and good recanalization (OR 3,006; 95% CI 1,439 – 6,276; p = 0,005) were both independent factors in predict the good outcome (mRS 0-2) at 90 days after treatment Thesis layout: The thesis consists of 128 pages Apart from the introduction (2 pages), the conclusion (2 pages), the recommendations (1 page) and the limitation (1 page), it also has four chapters include: Chapter 1: Overview 43 pages; Chapter 2: Materials and methods 18 pages; Chapter 3: Results 25 pages; Chapter 4: Discussion 36 pages The thesis consists of 26 tables, 26 pictures, 10 charts, and 182 references (Vietnamese: 8, English: 174) Chapter OVERVIEW 1.1 Literature review in the world In terms of diagnosis, according to the recommendations of the American Heart Association and Stroke, computed tomography is still preferred while magnetic resonance imaging is recommended for the diagnosis of vertebro - basilar occlusion or wake-up stroke Evaluation of collateral circulation was studied by Menon since 2014 on 140 patients and then showed that this method has good reliability in assessing collateral in ischemic areas (n = 30, k = 0.81 , p 0, 05) The rate of symptomatic hemorrhagic transformation post treatment was 11.8% and good outcome (mRS 0-2) after months was 47.1% 2.2 Methodology 2.2.1 Methodology Prospective clinical intervention study, pre and post treatment evaluation, non-randomized, non-blind and no control group 2.2.2 Number of patient Estimated 227 patients 2.2.3 Data analysis The data were analyzed using SPSS 22.0 software Algorithms used in the study include:: - General descriptive statistics of research variables - Qualitative variables are described by frequency and percentage, using the X2 test (if the standard variable) or the "Fisher exact test" (when the non-standard variable with any expected frequency has a value < 5) - Quantitative variables are described by mean and standard deviation (if standard variable) or median value (if non-standard variable) When comparing means: use T-test with standard variables and Mann-Whitney test with non-standard variables For multiple means, use the ANOVA test with the standard variable and the Kruskal–Wallis test with the non-standard variable - Perform binary comparison to identify significant clinical, imaging, and interventional factors affecting the good revascularization rate (TICI 2b-3) and good clinical recovery (mRS 0-2) after months - Perform multivariable regression analysis to variables with independent prognosis to predict the good recanalization (TICI 2b-3) and good clinical recovery (mRS 0-2) after months follow-up - p was considered as a significant difference when its value ≤ 0,05 Chapter MATERIALS AND METHODS 2.1.Research subjects 2.1.1 Inclusion criteria Based on AHA/ASA 2018 guidelines and recommendation: - Age ≥ 18; NIHSS ≥ - ASPECTS ≥ with anterior occlusion; for posterior occlusion: pc-ASPECTS ≥ or no pons lesion idenntified - Eveidence of large vessel occlusion (ICA, M1, M2, basilar artery) showed in diagnostic imaging - Time from onset to administration not more than 16 hours For late window – 16 hours: criteria based on DEFUSE (core volume ≤ 70ml and ratio of penumbra/ core ≥ 1,8) - Patient’s familly understand about the procedure and agree to sign in a commitment to treatment 2.1.2 Exclusion criteria - Wake-up stroke - Any hemorrhage shown in image - Chornic occlusion (Moya Moya disease…) - Pre - mRS ≥ (before stroke) - Severe condition with other diseases (kidney failure, invasive cancer…) and could not be followed up Chapter RESULTS The study was conducted on 227 patients (N) with acute ischemic stroke who underwent mechanical thrombectomy at the Radiology Center of Bach Mai Hospital: 205 cases (N1) with anterior occlusion and 22 cases (N2) ) with basilar occlusion There were 178 patients (N3) who came to the hospital in the first 4.5 hours and 32 cases came within the 6-16 hour window (that was controlled by perfusion nimaging) 3.1 General characteristics of the patients 3.1.1 Age and gender - Mean was 65±13 (22-90) The age group < 45 years accounted for 5.7%, the middle-aged group (45-69) accounted for 55.5% and the elderly group (>70) accounted for 38.8% Male/female ratio = 1.2% 3.1.2 Clinical and time characteristic at hospital admission - The rate of hypertension was 59.5%, hyperglycemia was 58.6% and atrial fibrillation was 24.7% NIHSS score at admission was 14.27 ± 4.8 - The mean time from onset to hospital admission was 203 ± 153 minutes; from hospital admission to first image was 39 ± 37 minutes; from hospital admission to femoral puncture was 98 ± 55 minutes 3.2 Imaging characteristic of large vessel occlusion 3.2.1 Occlusion site - The rate of M1 middle cerebral artery occlusion was 41.9% (95 patients), internal carotid occlusion was 23.8%, M2 segment occlusion was 13.2% and tandem occlusion was 11.5% There were 9.7% cases (22 patients) of basilar artery occlusion 3.2.2 Non contrast imaging charateristic - The mean ASPECTS and pc-ASPECTS was 7.76 ± 1.20 and 7.55 ± 1.62, respectively The time from onset to the first scan of anterior and posterior occlusion was 241 ± 148 minutes and 243 ± 181 minutes, respectively - For anterior occlusion, there was a significant difference in ASPECTS at different sites (p=0.01): M2 occlusioin had the least parenchymal damage with an average ASPECTS score of 33 ± 1.09 and the time from onset to the first imaging was shortest: 148 ± 130 minutes (p= 0.05) Occlusion of the internal carotid artery and the M1 had more parenchymal damage, respectively the average ASPECTS of 7.69 ± 1.23 and 7.54 ± 1.13 Time from onset to hospital imaging of the tandem group was the longest: 279 ± 227 minutes, p = 0.02 - The group of patients with more severe clinical condition (higher NIHSS) had more parenchymal damage (ASPECTS 6-7) and vice versa, but the difference was not statistically significant (p = 0.09) 3.2.3 Collateral characteristic in CT Scanner multiphase - The mean collateral score was 3.32 ± 1.44 (for anterior occlusion) Tandem group had the best collateral score (3.5 ± 1.3) but the difference was not statistically significant when compared with others (p = 0.95) - The group of patients with good clinical status (lower NIHSS) has a better collateral score (13.1 ± 4.3) and vice versa There was a statistically significant difference between the study groups (p=0.04) 3.2.4 Perfusion imaging characteristic - 32 patients admitted to the hospital with time window > hours underwent cerebral perfusion imaging The mean time was 505 ± 134 (min) and the mean core volume was 23.50 ± 9.00 (cm3) - Less parenchymal lesions (ASPECTS 8-10) have a smaller core volume (20.85 ± 9.35) compared with more parenchymal lesions (ASPECTS 6-7) corresponding to a larger core volume (26.58 ± 7.81) but the difference was not significant (p = 0.07) Time from onset to hospital admission between groups was not significant also (p = 0.61) - Core volume decreased gradually from the group with poor collateral circulation (29.00 ± 5.52) to moderate (23.74 ± 7.76) and good (21.81 ± 10.15) while penumbra volume gradually increased, 2.50 ± 0.75 (poor); 3.57 ± 1.86 (moderate) and 5.11 ± 3.42 (good), respectively The difference was not statistically significant (p = 0.30 and 0.14) The time from onset to hospital admission was different between groups, but not statistically significant (p = 0.27) 10 3.3 Endovascular mechanical thrombectomy effect 3.3.1 Characteristic and general results - Of the 227 patients undergoing mechanical thrombectomy, 80.6% received endotracheal anesthesia and 19.4% received local anesthesia The average intervention time was 40 ± 27 minutes (9 – 150) with an average number of pass was 2.73 ± 1.58 There were 178 patients admitted to the hospital in the first 4.5 hours of which 64 cases (accounting for 28.2%) were treated with rt-PA - The good recanalization (TICI 2b-3) was 84.6% There were patients with severe complications related to the procedure: cases of dissection (1.8% - of which case died, accounting for 0.4%) and cases of perforation (0.9% - leading to both mortalities) The mean number of thrombectomy pass was 1.87 times (median 1, range 1-10) - 24 hours follow-up, the mean NIHSS was 10.68 ± 7.76, lower than that at admission with an average reduction of 3.59 ± 4.0 points 130 patients decreased ≥ points and 61 patients decreased ≥ points with 86.9% of them having good clinical recovery after months - 148 patients had a good clinical recovery (mRS 0-2), reaching the rate of 65.2% while 29 cases of death (mRS 6) accounted for 12.8% patients had symptomatic transformation, accounting for 3.1% Asymptomatic hemorrhage seen in 50 patients, accounting for 22% - Good clinical recovery after months (mRS 0-2) seen in occlusion group of internal carotid artery, M2, tandem and M1 were: 59.3%, 63.3%, 69.2% and 73.7%, respectively Occlusion of the middle cerebral artery (M1 and M2 segments) had a lower mortality rate, 6.3% and 6.7%, respectively With posterior circulation, the good clinical recovery rate was only 40.9% while the mortality was highest (45.5%) 11 Figure 3.1 Rate of good recanalization and clinical recovery by number of thrombectomy pass - 47.6% had good revascularization (TICI 2b-3) and 35.2% had good clinical recovery (mRS 0-2) with only pass The cumulative rate of good recanalization increased to 66.1% and 77.1% after the 2nd and 3rd pass After the 4th, the increase was not significant ( 0.05) Good clinical recovery and mortality after months in intervention groups did not show a statistically significant difference (p = 0.32) 3.3.2.2 Based on treatment in the first 4.5 hours - Characteristics at hospital admission between the treatment groups did not differ (p > 0.05) in terms of imaging and most of the clinical features The time from onset to hospital admission in the combined group (IV rt-PA + thrombectomy) was significantly shorter (p < 0.05), but the time variables from hospital admission to femoral artery puncture did not differ between the groups (p > 0.05) Table 3.2 Results comparison between groups of treatment in the first 4.5 hours - Between the groups of device, the occlusion rate at M1, basilar artery and tandem was similar but the stent group had a lower rate in the internal carotid artery (12.9%) and higher in the M2 (22.6%), the difference was significant (p < 0.05) The rate of using combined intravenous rt-PA before thrombetomy in all groups did not differ: 26.7% - 30.1% with p = 0.83 - The mean intervention time in aspiration group was shortest: 35 ± 23 minutes, the difference was not statistically significant (p = 0.21) The average number of pass in the stent group was least (1.61) with significant difference (p = 0.02) The stent group had a significantly lower rate of rescue therapy (using a second device) than the aspiratiion group: 7.52% versus 33.33%, p < 0.05 The rate of good recanalization (TICI 2b-3) achieved at first pass was highest in the stent group: 61.3%, p = 0.04 but the general recanalization was all good post procedure in all groups without statistical difference (p = 0.55) - In the group of thrombectomy alone, the occlusion rate in the internal carotid artery was higher (28.1%) while in the M2 and tandem group, this rate was lower (12.3% and 7.9%) compared with combined group, the difference was statistically significant (p < 0.05) 14 15 Other parameters related to the procedure including time of intervention, number of pass, good recanalization and hemorrhagic transformation rate, there was no difference (p > 0.05) The good clinical outcome after months in the groups of treatment did not show a statistically significant difference (p = 0.60) 3.3.3 Independent factors affecting the good recanalization and good clinical recovery rate after months - Factors affecting the good recanalization were: no extracranial stenosis (p = 0.022) and intervention time ≤ 60 minutes (p = 0.000) In multivariate regression analysis, intervention time ≤ 60 was the most independent factor affecting the good revascularization rate post treatment (OR 5,952; 95% CI 2.755 – 12,821, p = 0.000) - Factors correspondinig to the rate of neurological recovery after months were: age < 80, hypertension, atrial fibrillation, NIHSS admission < 18 points, degree of collateral circulation, degree of revascularization and symptomatic transformation post thrombectomy (p < 0.05) In multivariable regressionn analysis, age 70 years old) accounted for 38.8%, of which the group > 80 years old accounted for 14.1% (32 patients) According to the current data, older age is not a contraindication to mechanical thrombectomy It should be noted that the rate of stroke in young people tends to increase, especially in the 40-45 year old group Our study recorded that young patients with cerebral ischemic stroke accounted for 5.7%, similar to the statistics in the world (from < 5% to 20%) Additionally, the research results showed that men predominate in terms of gender with 55%, 1.2 times higher than women, lower than Vu Viet Lanh study (60.4% male, male/female ratio was 1.5) 4.1.2 Clinical and time characteristic at hospital admission Our study recorded the mean value of NIHSS at the time of admission was 14.27 ± 4.8 (range 8-20), which were both lower than other international studies In an analysis of 1281 patients, Adam et al showed that NIHSS was valuable in predicting clinical outcomes after treatment, with a score of < having a good prognosis while a score of > 16 was often related with high mortality and disability rates In our study, the proportion of patients with hypertension and hyperglycemia predominated, 59.5% and 58.6%, respectively The rate of hypertensive patients was similar to the study by Toyoda (61%) and significantly higher than the study of Mai Duy Ton and Dao Viet Phuong (27.9%) In this study, we discovered atrial fibrillation by electrocardiogram in 56 patients, accounting for 24.7% This result is lower than that of Vu Viet Lanh (26%) and MR CLEAN (28.3%) In our study, the median value of time from onset to hospital admission as 165 minutes Compared with international studies, this was still a long time (1.5-2 times) and would reduce the patient's chance of getting treatment It was noteworthy that the time from imaging to femoral puncture was shortened with a median value of 51 minutes, equivalent to the value in the ESCAPE study and shorter when compared with EXTEND-IA and SWIFT PRIME trials 4.2 Imaging characteristic of large vessel occlusion 4.2.1 Occlusion site The results in our study showed that the distribution of occlusion site was consistent with the general trend of large studies in the world when the anterior circulation accounts for the majority (90.3%) with 16 17 95 cases of M1 occlusioin (41.9%) while the vertebro-basilar occlusion only account for 9.7% 4.2.2 Non contrast imaging charateristic We found that the group of patients with large vessel occlusion (internal carotid artery, M1 and basilar artery) had a higher degree of parenchymal damage, corresponding to an average ASPECTS/ pcASPECTS of 7.69 ± 1.23 , 7.54 ± 1.16 and 7.55 ± 1.62 The M1 group had lower ASPECTS values compared to other sites of the anterior circulation The reason was that the patients in this group had a late admission time (215 ± 136 minutes), so there was more parenchymal damage, the difference was statistically significant (p < 0.05) A special feature was that the tandem group had the time from onset to hospital admission and from onset to imaging was longest (242 ± 221 minutes and 279 ± 227 minutes, respectively), however, the parenchymal lesions according to ASPECTS were not much (only inferior to M2 occlusion group) This was consistent with the progression of chronic vascular stenosis that helped to created good collateral anastomosis Our study did not have a low ASPECTS subgroup (< 6), but the analysis results also showed a concordance between imaging and clinical in patients with ASPECTS 6-7 (moderate parenchymal lesions) had worse clinical status in cobination with higher NIHSS (14.3 ± 4.6) at the time of admission This was similarly to the study of Mai Duy Ton and Dao Viet Phuong 4.2.3 Collateral characteristic in CT Scanner multiphase When assessing collateral circulation in patients with anterior occlusion (205 cases) by CT Scanner multiphase, we recorded an average collateral score of 3.32 ± 1.44, in which 119 cases with good circulation (58%), 60 cases with moderate (29.3%) and 26 cases with poor collaterals (12.7%) The M1 occlusion group had the lowest collateral score (3.27 ± 1.41) while the tandem group had the highest collateral score (3.5 ± 1.3), which was suitable thanks to the presence of surface collateral The study results also showed that, in the group of patients with good collateral circulation, the mean NIHSS at baseline was lower (13.1 ± 4.3) compared with the other two groups (> 14.5), a statistical significant difference This was similar to the conclusion of Hwang when evaluating 86 patients with middle cerebral artery occlusion, noting that the group with poor collateral circulation had a severe clinical condition and a higher risk of atrial fibrillation compared with the another group without these factors 4.2.4 Perfusion imaging characteristic There were 32 cases admitted to hospital beyond 6th hour needed to undergo computed tomography perfusion The results showed that although the mean time to hospital admission of this group was 505 ± 134 minutes (equivalent to 6.5 hours), the average ischemic core volume recorded was only 23.5 ± 9.0ml The ratio of the volume between the penumbra and the core was 4.23, consistent with the selection criteria of DEFUSE When comparing in the subgroups based on ASPECTS and collateral score, the results showed that good ASPECTS (8-10) and good collateral score (4-5 points) corresponding to the lower core volume on cerebral perfusion map (20.85 ± 9.35 vs 26.8 ± 21.08 or 21.81 ± 10.15 vs 23.74 ± 7.76 and 29.0 ± 5, respectively) EXTEND-IA was one of the pioneering studies using quantitative assessment based on infarction volume (measured on perfusion map) passes, which was similarly to our results In our study, the average intervention time was 40 ± 27 minutes In the large European studies, ESCAPE had the prominence of early recanalization (median 30 minutes, range 18 - 45.5) This yielded positive results when comparing the clinical recovery after 90 days between the intervention group (52%) and the rt-PA alone group (29%) The good recanalization rate in our study was 84.6%, in which the level of TICI accounted for 53.3% (121 patients) and TICI 2b accounted for 31.3% (71 patients) This was higher when compared with the well-known studies conducted in 2016 with using 2nd generation devices such as MR CLEAN (58%), ESCAPE (72%) or REVASCAT (66%) and thus, outperforming other older studies using 1st generation in 2013 (IMS III: 38% or MR RESCUE: 27%) We recorded cases (2.6%) of severe complications related to the intervention, of which cases resulted in death, accounting for 1.3% This complication rate was similar to other trials such as SWIFT PRIME (4/98 patients with subarachnoid hemorrhage) or EXTENDIA (1/70 patients with perforation) Follow-up after 24 hours, we noticed 50 cases of asymptomatic hemorrhage (22%) and only cases of symptomatiic transformation (3.1%) The rate of transformation in general accounted for 25.1%, higher than that of the REVASCAT (21.4%) but lower than that results from Dao Viet Phuong (29%) The rate of symptomatic intracranial hemorrhage was also higher in the results of Vu Viet Lanh (12.5%) and Dao Viet Phuong (5.8%) compared to ours (3.1%) The mean NIHSS after 24 hours of intervention in our study was 10.68 ± 7.76 (median 8) with an average reduction of 3.59 ± 4.0 compared to the time of hopital admission This rate of Dao Viet Phuong was 70.9%, higher than our result of 57.3% partly due to the sooner window (only 4.5 hour) in the criteria selection If we used the criteria with NIHSS decline points, we had 26.9% of cases at 24 hours while Dao Viet Phuong recorded a rate of 55.8%, all significantly lower compared with the results of the EXTEND-IA study (80%) After months of follow-up, out of 227 patients receiving thrombectomy treatment at Bach Mai hospital, we recorded that 148 cases (65.2%) recovered well with mRS 0-2, 50 cases (22%) ) recovered slowly with mRS 3-5 and 29 cases (12.8%) died (mRS 6) This result was only inferior to that published by Dao Viet Phuong and EXTEND-IA study and similar to SWIFT PRIME but better than most of the ESCAPE, REVASCAT or MR CLEAN trials 4.3.2 Comparison in groups of treatment 4.3.2.1 Based on mechanical device Among 227 patients, 90 cases of initial treatment with stent retriever, 90 cases of aspiration (by large bore catheter), and 44 cases of solumbra technique (the combination of both devices) When comparing the clinical and imaging characteristics at the baseline, there were similarities between the treatment groups in terms of age, gender, comorbidities, NIHSS, ASPECTS/pc-ASPECTS (p > 0.05) Time table anaylysis recorded a trend towards earlier hospital admission in the stent group (193 ± 146 minutes versus 214 ± 154 and 203 ± 265 minutes, p = 0.41) while the time from admission to femoral puncture in the solumbra group was shorter (85 ± 38 vs 107 ± 58 and 96 ± 58 min, p = 0.04) Intervention time in the aspiration group was shortest (35 ± 23 min) while the stent group and the solumbra group lasted longer, 41 ± 26 and 46 ± 34 min, respectively, p = 0, 21 This was consistent with the study of Turk or Procházka, when the aspiration tube only need to be in contact at the proximal part of thrombus However, the number of pass to remove thrombus was the most in our group using aspiration alone (2.11 passes, 1–10) compared to other two groups (stent: 1.61 passes, 1–10) and Solumbra: 1.93 passes, 1–6), p=0.02 This inconsistency could be explained by the distribution of occlusion sites in the treatment groups in Table 3.1 The impressive final good recanalization resulted 20 21 in the aspirationn group could be explained by the rate of rescue therapy (switching from treatment alone to combination) up to 33.33%, times higher compared with only 7.52% in the initial stent group, p = 0.00 This was similar to that in the ASTER study, with a resuce rate of 33% in the aspiration group but 24% in the stent group, which helped to increase the total good recanalization rate in the aspiration group from 63% → 85.4% and stent group from 68% → 83.1%, p = 0.53 All our groups recorded a relatively high successful outcome rate (mRS 0-2): the stent group was 66.7%, the aspiration group was 65, 6% and the solumbra group was 61.4%, no statitically significant difference, p = 0.32 The mortality rate in the stent group was only 7.6%, much lower than the other groups (respectively 15.5% and 18.2%) which was thought to be consistent with the causes mentioned above: early admission time, lower rates of both internal carotid occlusion and symptomatic intracraninal hemorrhage post treatment This result was similar to the ASTER study where the good clinical recovery rate between the stents and aspiration group was not different (50% and 45.3%, OR 0.83 [95% CI, 0.54-1.26], p = 0.38) while Procházka recorded a better clinical recovery in the groups using stents and aspiration tubes compared to the solumbra group (p < 0.05) 4.3.2.2 Based on treatment in the first 4.5 hours Our comparison of 178 patients admitted at a 4.5-hour window received thrombectomy with intravenous rt-PA (64 patients) versus thrombectomy alone (112 patients) Although not randomized, the characteristics of age, sex, NIHSS or ASPECTS at the baseline were similar between these groups Time from hospital admission to femoral puncture (103 ± 56 minutes vs 95 ± 61 minutes, p = 0.37) was not prolonged in the combined group, and even more urgently with the rate of procedure time ≤ 90 minutes was 57.8% compared to 50.9%, p = 0.37 This suggested that the concern that the use of intravenous rt-PA may slow down the interventional treatment does not seem to be really suitable The rate of good recanalization after rtPA in combination with mechanical thrombectomy was similar to that of intervention alone: 90.6% vs 87.7%, p = 0.56 (table 3.2) This showed that the use of thrombolysis was not necessarily the key factor affecting the outcome of recanalization in large vessel occlusion Additonally, we found that the endovascular time in the group of thrombectomy alone tended to be shorter than the combined group (37 ± 27 minutes and 41 ± 26 minutes, respectively, p = 0.19) was consistent with the less number of pass: 1.79 ± 1.26 times (median 1, range - 6) versus 2.06 ± 1.28 times (median 2, range 10), p = 0.11, respectively The rate of intervention time within 45 minutes also showed a better value in the thrombectomy alone group: 71.1% of cases compared with 68.8%, p = 0.74 The similarity in our results with the study of Weber (good recanalization rates in the two groups were 73.8% and 73.1%, p = 0.95; the time reports around the procedure were similar but shorter in the thrombectomy group alone) again supported the hypothesis that the use of rt-PA tended to fragment the intracranial thrombus, leading to intervention migration The overall rate of intracerebral hemorrhage within 24 hours tended to be higher in the combinend group (28.1% vs 24.6%, p = 0.6) while the rate of symptomatic transformation was higher in the group of thrombectomy alone (5.3% vs 1.6%, p = 0.42) but the difference was not statistically significant Our study and most recent international studies did not show any evidence of association between intravenous rt-PA and the risk of hemorrhage after treatment, which was consistent with the results of Mai Duy Ton and Dao Viet Phuong The rates of good clinical recovery (mRS 0-2) and mortality (mRS = 6) observed after follow-up in the two groups of patients were similar (65.6% and 17.2% in the combined group versus 66.7% and 12.2% in the thrombectomy alone group, p = 0.60) 4.3.3 Independent factors affecting the good recanalization and good clinical recovery rate after months - When analyzing factors related to recanalization level, we found that clinical factors such as: age (< 80), gender (male), atrial fibrillation, occlusion site did not affect the recanalization efficiency (p > 0.05) More interestingly, intravenous rt-PA did not play any siginificant role in this results also (p > 0.05) Of the two factors 22 23 related to good recanalization (TICI 2b-3), we concluded that the procedural time within 60 minutes (90.6% vs 61.7%, p = 0.000) played a more important role than non-extracranial stenosis factor (86.6% vs 69.2%, p = 0.022) This was shown in multivariate regression analysis, when intervention time ≤ 60 was an independent predictor of good recanalization (OR 5,952; 95% CI 2.755 – 12,821, p = 0.000) compared with non-extracranial stenosis (OR 2.890; 95% CI 1.131 – 7.353, p = 0.068) The results were consistent with Vanacker's study on 439 patients showing that extracranial stenosis combined with intracranial thrombosis (tandem occlusion) reduces > 50% of good revascularization (ROC value is 0.72) and mechanical thrombectomy was the most important factor promoting revascularization in acute ischemic stroke - Regarding to the level of neurological recovery after months, we evaluated based on clinical factors (age, comorbidities, NIHSS, time), imaging factors (ASPECTS, collateral grade, occlusion site) and interventional-related factors (combined extracraninal stenosis, recanalization grade, first-pass effect, symptomatic intracraninal hemorrhage) Multivaria regression analysis results for factors including: age 0.05) - Based on with versus without rt-PA in combination with thrombectomy: there was no significant difference in the number of pass, the good recanalization rate, the hemorrhagic rate post treatment as well as the rate of neurological recovery or death at the time of follow-up after months (p > 0, 05) * Evaluate relevant factors: CONCLUSION Through a study on 227 acute ischemic patients with large vessel occlusion who underwent mechanical thrombectomy at the Radiology Center of Bach Mai hospital from January 2018 to June 2019, we concluded that: 24 - Intervention time ≤ 60 (OR 5,952; 95% CI 2.755 – 12,821, p = 0.000) was an independent predictor of good revascularization (TICI 2b-3) Meanwhile, age < 80 (OR 3.842; 95% CI 1.764 – 8.365; p = 0.011), NIHSS admission < 18 points (OR 4.917; 95% CI 2.524 – 9,580; p = 0.000), good collateral circulation (OR 15,047; 95% CI 7.181 – 31,529; p = 0.000) and good revascularization (OR 3.006; 95% CI 1.439 – 6.276; p = 0.005) were independent prognostic factors for good clinical recovery (mRS 0) -2) at 90 days after treatment RECOMMENDATION In the diagnosis of acute ischemic stroke, CT multiphase should be done to evaluate the grade of collateral circulation More studies with a larger number of patients are needed to conduct in Vietnam in order to confirm the role of cerebral perfusion imaging technique in the selection of stroke treatment in late window time (≥ hours) Mechanical thrombectomy has been again shown to be effective with good revascularization and clinical recovery rates, and very low related -complications The comparison showed no difference in outcomes between groups of treatment with different device selections (stent, suction, combination) or treatment methods (with/ without rtPA) within the first 4.5h However, more studies with randomized controlled design are needed to overcome the limitations of our study LIMITATION Despite the large sample size, we have not been able to perform a randomized or controlled study as expected Therefore, the subgroup analyzes when comparing the treatment effectiveness between choices of devices or intervention methods still had biases This is also an inherent weakness when conducting research in Vietnam compared to international ones, but it is also an expectation that further studies will have better design with best support and effort