Mechanical thrombectomy of acute ischemic stroke of Medium Sized Vessels (M2 segment of middle cerebral artery occlusion)

doi:10.21203/rs.3.rs-5253221/v1

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Research Article

Mechanical thrombectomy of acute ischemic stroke of Medium Sized Vessels (M2 segment of middle cerebral artery occlusion)

https://doi.org/10.21203/rs.3.rs-5253221/v1

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Background

Data on mechanical thrombectomy (MT) to treat M2 occlusions of the middle cerebral artery (MCA) are sparse. We report the outcome and safety of MT versus intravenous recombinant tissue plasminogen activator (IV rTPA) versus conventional medical treatment of acute ischemic stroke (AIS) due to occlusion of the M2 segment of the MCA. This prospective study compared the outcomes and safety of MT, rTPA, and conventional medical treatment in M2 occlusion AIS patients. National Institutes of Health Stroke Scale (NIHSS), Modified Rankin Scale (mRS), and recanalization rate assessed outcomes.

Results

74 AIS patients were recruited (23 MT, 23 rTPA, 28 conventional treatments). MT group had significantly higher admission NIHSS (p = 0.037). At 24 hours, NIHSS improved more with MT and rTPA than conventional treatment (p < 0.0001). At 3 months, mRS were better with MT and rTPA versus conventional treatment (p < 0.0001). Successful recanalization occurred in 73.9% of the MT group. 69% of the MT group required stent retrieval plus aspiration thrombectomy and 60.9% required ≥ 3 trials, but outcomes did not differ by technique or number of trials. A good outcome (mRS 0–2) at 3 months was achieved in 69.6% MT versus 65.2% rTPA versus 7.1% conventional treatment (p < 0.0001). Symptomatic intracranial hemorrhage (sICH) rates were slightly, but insignificantly, higher with conventional treatment. Mortality did not significantly differ between groups.

Conclusions

For M2 occlusions, MT and rTPA achieved better early and 3-month outcomes than conventional management, however, MT was not superior to rTPA. MT of M2 is feasible and effective, with a lower hemorrhage rate than rTPA and conventional treatment.

Trial registration

This study was prospectively registered in the clinical trial with ClinicalTrials.gov ID (NCT05091320). The link https//clinicaltrials.gov/study/NCT05091320

Mechanical thrombectomy

rTPA

M2 segment

catheter retrieval

Acute ischemic stroke (AIS) is typically categorized into large-vessel occlusion (LVO) and non-LVO. LVOs occur when the proximal arteries in the anterior circulation are occluded [1]. LVOs account for approximately 35%-40% of AIS cases, while medium-vessel occlusions (MeVOs) are responsible for 25%-40% [2, 3].

MeVOs are defined as occlusions of the M2 and M3 segments of the middle cerebral artery (MCA), A2 and A3 segments of the anterior cerebral artery (ACA), or P2 and P3 segments of the posterior cerebral artery (PCA). Distinguishing between LVOs and MeVOs can be challenging, particularly when M2 occlusions of the dominant branch produce symptoms similar to M1 occlusions [2, 3]. A multidimensional definition considering both morphological aspects and clinical impairments may be preferable due to the heterogeneity in anatomy and clinical presentation [4].

Mechanical thrombectomy (MT) has shown superior efficacy to intravenous thrombolysis using intravenous recombinant tissue plasminogen activator (IV rTPA) for M1 occlusions in recent clinical trials [5, 6]. While M2 occlusions exhibit higher rates of revascularization with IV rTPA compared to proximal occlusions, MT may serve as an effective alternative when rTPA is ineffective or contraindicated [7–9]. Based on recent studies that compared the outcomes of M1 and M2 occlusions treated with MT, MT has emerged as a promising treatment option for M2 occlusion. Bala and colleagues (2023) reported superior clinical outcomes and reduced symptomatic intracranial hemorrhage (sICH) rates for M2 occlusions treated 6–24 hours after symptom onset [10]. Similarly, a meta-analysis by Liyis and colleagues (2023) showed that patients with M2 occlusions had lower baseline NIHSS scores and better functional outcomes at 90 days, albeit with lower recanalization rates than M1 occlusions [11].

Although MT for MeVO has shown promise as a therapy option, it does include hazards such as vascular perforation and sICH. Dmytriw and colleagues (2024) reported a 4.8% rate of vessel perforation during MT for MeVO, associated with poor functional outcomes and higher mortality [12]. Yedavalli and colleagues. (2024) noted an 8.7% occurrence rate of sICH in MeVO patients treated with MT, identifying several risk factors [13]. These studies underscore the importance of careful patient selection and consideration of individual risk factors when performing MT for MeVO [12, 13].

Several studies comparing MT to IV rTPA best medical management (BMM) for distal medium vessel occlusions (DMVOs) and M2 segment occlusions have yielded mixed results. Sarraj and colleagues (2022) conducted a pooled patient-level analysis of five studies, finding that MT was associated with improved functional independence and lower mortality compared to BMM. This benefit was primarily observed in patients with a perfusion mismatch profile and moderate to severe stroke severity [14]. Recently, Salim and colleagues (2024) found no significant difference in functional independence at 90 days between MT and BMM for DMVOs but noted higher rates of hemorrhagic complications with MT [15]. Similarly, Zhou and colleagues. (2024) reported no statistical difference in favorable outcomes between MT and IV rTPA alone for M2 occlusions, with MT associated with higher rates of subarachnoid hemorrhage and pneumonia [16]. Zhou's subgroup analyses suggested IV rTPA might be preferable for certain occlusion types. These findings highlight the need for careful patient selection and further research to refine treatment strategies for these specific stroke subtypes [16].

To establish MT as standard care for MeVO patients, high-level evidence from randomized controlled trials is necessary. A recent review by Ospel and colleagues (2024) summarizes five ongoing MeVO randomized controlled trials for endovascular treatment. These trials - DISCOUNT, DISTAL, DISTALS, ESCAPE-MeVO, and FRONTIER-AP - collectively aim to evaluate MT efficacy in MeVOs, with sample sizes ranging from 168 to 530 patients. They focus on various distal arterial occlusions, including M2/M3 of MCA, anterior cerebral artery, and posterior cerebral artery branches. Primary outcomes were largely centered on functional independence at 90 days, as measured by the modified Rankin Scale (mRS). The trials also differ in their time windows for intervention (6 to 24 hours from the last known well), imaging criteria, and allowed thrombectomy devices. This review aimed to address the current knowledge gap regarding the optimal management of MeVOs, potentially expanding the indications for endovascular therapy in AIS [17].

Given the current knowledge and the lack of such comprehensive studies comparing all treatment options for M2 occlusions in the Egyptian healthcare context, there is a critical need for region-specific evidence to guide clinical practice. In Egypt, where stroke care resources and practices may differ from those in previously studied populations, a direct comparison of MT, IV rTPA, and conventional medical treatment for M2 occlusions is particularly warranted. This study aims to address this need by comparing the efficacy and the short- and long-term outcomes of MT versus IV rTPA versus conventional medical treatment in AIS patients with occlusion of the M2 division of the MCA.

This interventional study was conducted from December 1, 2021, to November 30, 2023. In this study, patients with AIS were included consecutively as they presented to the emergency departments of [blind] University Hospitals (AIS patients eligible for MT) and [blind] University Hospitals (AIS patients eligible for rTPA or conventional treatment if rTPA was unavailable or patients arrived at the hospital out of the time window for rTPA) due to occlusion of the M2 division of the MCA assessed by CT angiography or MR angiography.

Inclusion criteria were age > 18 years, cerebral infarction due to M2 occlusion of MCA, and eligibility for interventional (MT) or non-interventional reperfusion therapy (IV rTPA) or non-eligible to IV rTPA and received conventional treatment. All eligible patients during this time frame were included in the study, ensuring a representative sample without selection bias. No randomization was employed, as the study aimed to observe outcomes in a real-world setting.

The exclusion criteria included were proven to be proximal MCA occlusion or the cases where the occlusion was initially more proximal and then propagated distally and the refusal to participate in the study.

The M2 segment, or insular segment of the MCA, begins at the genu from the first bifurcation of the main MCA trunk, excluding the anterior temporal branch, and ends at the circular sulcus [1]. It comprises branches coursing along the insula within the Sylvian fissure, ascending vertically towards the distal insular circular sulcus before turning sharply to surround the opercula, marking the transition to the M3 segment [18].

The patients in this study were classified according to treatment modality [19], into three groups: 1) Mechanical thrombectomy (MT) group in which patients were recruited from [blind] University Hospital following AIS. The MT group was exclusively comprised of patients who were ineligible for rTPA due to late arrival but were eligible for MT. 2) The IV rTPA group comprised patients who were recruited from [blind] University Hospital arrived at the emergency unit within the time window (4.5 hours) and were eligible for IV rTPA. 3) The conventional treatment group included patients who were recruited from [blind] University Hospital and arrived at the emergency unit out of the time window for rTPA and received conservative management (Antithrombotic or Antiplatelet) due to unavailability of MT due to lack of equipment or personnel.

A detailed history was taken from all patients including age, sex, and different vascular risk factors (hypertension, diabetes mellitus (DM), atrial fibrillation (AF), hyperlipidemia, smoking, and ischemic heart disease). All patients were assessed at the time of presentation with the National Institutes of Health Stroke Scale (NIHSS), mRS scale, CT scan, and CT angiography or MR angiography (according to availability at the time of admission). All patients were reassessed clinically and with the NIHSS [20], 24 hours after receiving treatment with a final follow-up after 3 months using the mRS scale [21]. Laboratory routine investigations included detailed history and all routine laboratory tests: CBC, lipid profile, electrolyte level, renal function, and ECG.

Imaging: Patients who exhibited symptoms and radiographic evidence indicating medium-sized occlusions and who met the specified clinical criteria for MT underwent a thorough assessment of the arteries in the brain using arterial imaging. The preferred method for this evaluation is computed tomography angiography (CTA), although magnetic resonance angiography can be used as an alternative. Perfusion CT imaging or diffusion-weighted MRI imaging was employed to detect and measure the ischemic penumbra and evaluate patient suitability for MT within the extended time window. These imaging techniques were also used to confirm the M2 segment occlusion.

Interventions: The patients were admitted to stroke/intensive care units. In the IV rTPA group, patients received the rTPA within the 4.5-hour window per guidelines [19]. In the MT group, digital subtraction angiography (DSA) by expert neurointerventionists assessed the occlusion site. MT was performed under local anesthesia with conscious sedation and heparinized flush, using individualized thrombectomy devices (stent retrievers, aspiration, or combined) per FDA guidelines [22]. An 8F soft tip guiding catheter was introduced to the petrous part of ICA, and an intermediate catheter with stent retriever (Solitaire: Medtronic; FR; ev3 Neurovascular, Irvine, CA) and aspiration catheter (Sofia 5F: MicroVention Terumo) were used. Post-procedure Modified Thrombolysis in Cerebral Infarction (mTICI) score was used to evaluate revascularization. Data recorded included procedural time, thrombectomy method, trial number, and post-procedure Modified Thrombolysis in Cerebral Infarction (mTICI) score was used to evaluate revascularization, complications, and reperfusion injury.

Evaluation: All participants underwent clinical and neurological evaluations made at admission (baseline NIHSS and mRS), 24 hours after treatment (NIHSS), and 3 months later (mRS).

National Institutes of Health Stroke Scale (NIHSS)

This is the most frequently used neurological deficit rating scale, which possesses a maximal score of 42 (hypothetical due to the existence of numerous mutually exclusive items). NIHSS encompasses a maximal possible deficit of 42 and a range of 0 (no deficit) [20].

The modified Rankin scale (mRS)

this scale assesses the extent of functional neurological disability following a stroke. It encompasses a spectrum of severity, from no symptoms to mild disability (0–2), moderately severe disability (3–4), and severe/death (5–6) [21].

The Modified Thrombolysis in Cerebral Infarction (mTICI) score

this scale evaluates the angiographic outcome in the MT group. It ranges from 0 (indicating no reperfusion) to 3 (indicating full reperfusion in the distribution of the occluded artery). The score assesses both the recanalization of the original primary occlusive lesion and the reperfusion of the distal vasculature of the occluded artery at the end of the angiographic procedure [23]. Recanalization was considered successful if the post-procedure mTICI score was 2b/3[24]

Outcome Measures: The primary outcome was the percentage of patients who achieved a good functional outcome, defined as a Modified Rankin Scale (mRS) score of 2 or less at 90 days (functional independence). The clinical neurological outcome was assessed after 24 hours using the NIHSS. A good outcome was defined as an NIHSS score of 2 or less or a decrease in NIHSS score of 10 points or more after 24 hours. The secondary outcomes were assessed using the presence of symptomatic intracranial hemorrhage (sICH) within 72 hours and the mortality rate at 90 days.

The study received ethical approval from the [blind] University Faculty of Medicine (IRB 17200628 on 17/10/2021). The clinical trial was registered on ClinicalTrials.gov (NCT05091320). The research adhered to the ethical principles outlined in the World Medical Association's Declaration of Helsinki. Written informed consent was obtained from patients or relatives after explaining all aspects of the study and potential risks.

Statistical analysis was performed using SPSS 16.0 (SPSS Inc., Chicago, IL, USA). The Shapiro-Wilk test was used to assess normality, and the data was abnormally distributed. Continuous variables were represented by mean ± standard deviation (SD), median, and interquartile range (IQR), while categorical variables were represented by frequencies and percentages. The chi-square test was employed to compare categorical variables. The Mann-Whitney U test was utilized to compare continuous variables between two groups. The Wilcoxon signed-rank test was used to evaluate pre- and post-treatment changes in NIHSS and mRS scores within groups. The Kruskal-Wallis test was employed to compare continuous variables across the three treatment groups. The Friedman test was used to assess the time × group interaction for changes in NIHSS and mRS scores. A two-tailed p-value < 0.05 was considered statistically significant. All p-values reported in this manuscript were adjusted for multiple comparisons using the False Discovery Rate (FDR) correction method.

A total of 120 patients were initially screened for eligibility in this study. After applying the exclusion criteria, 46 patients were excluded: 20 due to proven proximal MCA occlusion, 15 due to internal carotid artery occlusion, 8 who refused to participate, and 3 had missing data. Consequently, 74 patients met the inclusion criteria and were enrolled in the study. These patients were then allocated into three treatment groups: 23 patients received MT, 23 received IV rTPA, and 28 received conventional treatment. (see Fig. 1, flowchart).

Table 1 shows demographic and risk factor data for the three treatment groups. 74 patients met the inclusion criteria and were enrolled in the study. These patients were then allocated into three treatment groups according to the time window as well as inclusion and exclusion criteria for each group: 23 patients received MT, 23 received IV rTPA, and 28 received conventional treatment (see Fig. 1, flowchart). There were no significant differences in terms of age, sex, and vascular risk factors such as hypertension, ischemic heart disease, and smoking among the three treatment groups. However, there are significant differences observed among the three groups regarding diabetes mellitus (p = 0.004), atrial fibrillation (p = 0.013), hyperlipidemia (p = 0.029), and NIHSS at admission (p = 0.037). In the MT group, the onset-to-groin time was 356.90 ± 79.79 minutes, and the revascularization time ranged from 20 to 80 minutes, with a mean of 45.81 ± 12.43 minutes. In the rTPA group, the onset-to-door time was 136.177 ± 40.57 minutes, and the onset-to-needle time was 56.95 ± 39.43 minutes.

Table 2 compares 24-hour NIHSS and 3-month mRS scores across three treatment groups. Patients who underwent MT and received rTPA showed significant improvements in NIHSS scores from admission to 24 hours following therapy (p < 0.0001), while the medical group showed no change (p = 0.72). The NIHSS scores at 24 hours showed significant differences across the three therapy groups (p < 0.0001), with MT and rTPA outperforming conventional treatment. All three treatment groups showed significant mRS score improvements from admission to 3 months post-treatment (p < 0.0001 for MT and rTPA, p = 0.001 for conventional treatment). Results showed significant differences in mRS scores at 3 months (p < 0.0001), with MT and rTPA achieving better functional outcomes than conventional treatment. The Freidman Measure Analysis showed a significant time x treatment interaction (p > 0.0001) for NIHSS and mRS scores across the three groups.

Table 3 compares the neurological and functional outcomes, measured by the NIHSS at 24 hours and the mRS at 3 months, among the three treatment groups. Regarding NIHSS scores at 24 hours, the MT group had significantly higher scores (indicating worse neurological outcomes) compared to the rTPA group (p = 0.035), but both were significantly better than the conventional medical treatment (p < 0.0001 for both comparisons). At 3 months, MT and rTPA groups had comparable mRS scores with no significant difference (p = 0.102), but both were significantly better than the medical treatment group (p < 0.0001 for both comparisons).

Table 4 summarizes the safety outcomes, including sICH rates and mortality. There was no significant difference in hemorrhage (p = 0.314) or mortality (p = 0.837) rates across groups. However, the MT (69.6%) and rTPA (65.2%) groups had significantly higher good functional outcomes (mRS ≤ 2 at 3 months) than the conventional treatment group (7.1%) (p < 0.0001).

Table 5 lists details of the MT procedure, including thrombectomy mode, trial number, and mTICI score. Mixed procedures combining stent retrieval and aspiration were used in 69% of cases. Most procedures (60.9%) required three or more trials. Successful recanalization (mTICI 2b/ 3) was achieved in 73.9% (Figs. 2 and 3).

This observational study aims to contribute to our understanding of the comparative effectiveness and safety of MT, IV rTPA, and conventional medical management for treating M2 MCA occlusions. Our analysis suggests several potential trends: 1) Patients treated with MT and IV rTPA appeared to have better 24-hour NIHSS scores compared to those receiving conventional treatment; 2) MT and IV rTPA groups showed a tendency towards improved 3-month mRS scores (≤ 2) relative to the conventional treatment group; 3) Successful recanalization after MT (73.9%) was associated with numerically, though not statistically significant, better NIHSS and mRS outcomes; 4) The observed safety profiles, including rates of sICH and mortality were comparable across the three treatment modalities.

In the current study, the baseline characteristics of the MT group were comparable to the other treatment groups (IV rTPA and conventional medical treatment) in terms of age and sex distribution. However, the MT group had a higher frequency of DM and hyperlipidemia, while the conventional treatment group had a higher frequency of AF. These observations highlight the importance of optimal management of stroke risk factors and suggest that MT could be advantageous for individuals ineligible for rTPA due to certain risk factors. The increased frequency of AF in the conventional group is likely because many were on anticoagulant therapy, making them ineligible for rTPA. The MT group had a higher NIHSS at admission than the other groups, which is similar to the findings of Miura and colleagues (2019) [25], who reported that the MT group had a higher baseline score than the rTPA group. Thus, MT may be a second-line treatment for AIS, offering revascularization to high-NIHSS patients ineligible for IV rTPA.

In this study, we did not measure admission glucose levels. However, the high incidence of diabetes, hypertension, and hyperlipidemia among the studied groups may partially explain the poor outcomes. This is supported by Bruno and colleagues (1999), who found that higher admission blood glucose levels were associated with worse outcomes at 3 months, according to multivariate logistic regression analysis adjusted for stroke severity, diabetes mellitus, and other vascular risks [26].

In the present study, despite MT's higher baseline NIHSS, the MT and IV rTPA groups showed significantly greater improvements in NIHSS scores 24 hours following therapy than the conventional group. Also, the MT (69.6%) and IV rTPA (65.2%) groups had better functional outcomes (mRS 0–2) at 3 months compared to the conventional treatment group (7.1%). These findings suggest that MT and IV rTPA interventions may be equally efficacious treatments for M2 occlusions, achieving comparable neurological outcomes in terms of 24-hour NIHSS or 3-month mRS scores. These results corroborate previous research indicating potential long-term advantages of MT for M2 occlusion patients [25, 27–31].

Marchal and colleagues (2022) found that MT improved neurological and functional results for distal M2 occlusions compared to medical management [28]. A recent meta-analysis by Barchetti and colleagues (2020) revealed an overall good functional outcome rate of 58.8% at the 3-month follow-up for MT in distal locations [32]. Vidale and colleagues (2021) conducted a systematic review and meta-analysis, comparing the risk-benefit profiles of MT with or without IV rTPA versus IV rTPA alone in adults with AIS and M2 occlusion. They found similar rates of good functional outcome (mRS < 3) at 90 days between the two strategies, MT versus IV rTPA (62.4% versus 66.3%, respectively) [31]. Moreover, Waqas and colleagues (2021), in their meta-analysis of patients who underwent MT for distal circulation strokes, found that 54.7% of patients who had MT achieved a favorable outcome at 3 months, which was comparable to the 54.5% of IV rTPA [33]. Furthermore, Guo and colleagues (2023) demonstrated in their meta-analysis that MT was associated with better functional outcomes (mRS 0–2) than best medical management in patients with M2 occlusion and moderate-to-severe stroke [27].

The current result suggests the potential benefits of MT in improving functional outcomes and reducing long-term disability in patients with DMVOs, which are often associated with poor prognosis when treated with conventional medical management alone. These findings lie in alignment with those of Menon and colleagues (2019), who reported improved functional independence in patients with M2 segment occlusion who received MT at 90 days compared to those who received the best medical treatment [29]. Similar effects were reported by Sarraj and colleagues. (2016) and Miura and colleagues (2019), underscore the superiority of MT management for M2 occlusions [25, 30].

sICH is the most feared complication of MT [34] especially in smaller vessels that are more vulnerable when treated endovascularly. Saber and colleagues (2018) conducted a meta-analysis of 1080 patients who underwent M2 thrombectomy, comparing them to those with M1 occlusions. The analysis suggests that M2 thrombectomy may carry an increased risk of sICH risk [35]. In the current study, the sICH rates across the three treatment groups appeared to show no notable differences. This observation is consistent with findings from previous studies [28–30, 36]. Menon and colleagues (2019) found no sICH in patients treated with MT for M2 occlusions compared with a 7.9% rate in the best medical management group (IV-tPA) [29]. Marchal and colleagues (2022), reported that sICH occurred in 3.1% of the MT group and 9.5% of the non-MT group [28]. Conversely, Vidale and colleagues (2021) found a higher sICH rate in the MT group (8.5%) compared to the IVT group (3%) [31]. Waqas and colleagues (2021) reported that 5.8% of patients who underwent MT for strokes in the distal locations experienced sICHs, comparable to 2.5% of patients treated with IV tPA [33].

In the present study, the mortality rate in the MT group appeared to be comparable with that of the other treatment groups, supporting the safety of this treatment modality, as shown in previous studies [25, 27, 36]. Miura and colleagues (2019) reported that MT was associated with lower mortality compared to medical management in a real-world cohort of patients with M2 occlusions [25]. However, Waqas and colleagues (2021) reported a 16.5% mortality rate for MT, comparable to 12.4% for IV tPA in treating strokes in distal locations [33]. It is important to consider the potential for susceptibility bias, as patients selected for MT were likely “sicker” and thus had a higher risk of mortality. Residual confounding may also influence these outcomes. Conducting RCTs is essential for more definitive conclusions.

Regarding the procedural aspects of MT, in this study, the subgroup analysis of the MT group suggests potential insights into the technical aspects of MT for M2. Most cases required a combination of stent retrieval and aspiration techniques, reflecting the complexity of these distal occlusions. Furthermore, multiple thrombectomy attempts were often required, with nearly 61% of cases requiring three or more passes. This may highlight some of the challenges associated with navigating and recanalizing these small intracranial vessels. However, given the limited sample size, these observations should be interpreted cautiously and may warrant further investigation in larger studies.

While providing initial insights into MT for the M2 segment of MCA occlusions, this study has several limitations. First, the limited sample size constrains the statistical power and generalizability of our findings. Second, the non-randomized, observational design introduces potential selection bias and confounding variables. Third, there is a possibility that patients selected for more aggressive interventions like mechanical thrombectomy had different baseline clinical characteristics, potentially influencing outcomes independently of the treatment effect. Fourth, the absence of perfusion imaging, due to resource constraints, limits our ability to assess cerebral blood flow comprehensively. Fifth, the study lacks a direct comparison to intra-arterial thrombolysis and does not explore the impacts of precise lesion location, collateral circulation, or time to revascularization. Finally, the absence of long-term follow-up beyond three months restricts our understanding of the sustained effects of the treatments. These limitations underscore the need for cautious interpretation of our findings and highlight the importance of future randomized controlled trials to establish causal relationships and more effectively control for potential confounding factors.

To address these limitations, future large-scale, multicentre, randomized controlled trials with perfusion imaging, particularly perfusion mismatching are recommended to validate findings, compare endovascular treatment modalities, identify predictors of successful recanalization and favorable outcomes, refine patient selection criteria, and optimize treatment strategies for M2 occlusions to help in improving patient outcomes. Such trials would provide more robust evidence to guide clinical decision-making in the management of M2 MCA occlusions.

This study suggests that MT and IV tPA are safe and effective treatments for M2 occlusions of MCA, with better neurological and functional outcomes than medical management. MT may be beneficial for this subset of stroke patients who are ineligible or unresponsive to standard rTPA. However, larger RCTs are needed to validate the findings and explore optimal treatment strategies, considering factors like lesion location, time to revascularization, and adjunctive therapies.

ACA

Anterior Cerebral Artery

Atrial Fibrillation

AIS

Acute Ischemic Stroke

CBC

Complete Blood Count

Computed Tomography

CTA

Computed Tomography Angiography

Diabetes Mellitus

DSA

Digital Subtraction Angiography

ECG

Electrocardiogram

FDA

Food and Drug Administration

HTN

Hypertension

ICA

Internal Carotid Artery

IV rTPA

Intravenous Recombinant Tissue Plasminogen Activator

LVO

Large Vessel Occlusion

MCA

Middle Cerebral Artery

MeVO

Medium Vessel Occlusion

mRS

Modified Rankin Scale

Mechanical Thrombectomy

NIHSS

National Institutes of Health Stroke Scale

PCA

Posterior Cerebral Artery

sICH

Symptomatic Intracranial Hemorrhage

mTICI

Modified Thrombolysis in Cerebral Infarction.

Ethical Approval and Consent to participate:

was approved by the Assiut University, Faculty of Medicine’s ethical committee and registered with the Institutional Review Board (IRB no: 17200628). The clinical trial was registered on ClinicalTrials.gov (NCT05091320). The research adhered to the ethical principles outlined in the World Medical Association's Declaration of Helsinki. Written informed consent was obtained from patients or relatives after explaining all aspects of the study and potential risks.

Consent for publication:

Not applicable.

Figures:

The authors confirm that all used figures in the current manuscript are original and they are from our research work.

Funding:

The authors received no financial support for this article’s research, authorship, and/or publication.

Author Contribution

EMK: Study conceptualization and design, data analysis, manuscript reviewing & editing. AEB: Study conceptualization and design, methodology, manuscript reviewing & editing. MN: Data collection, methodology, manuscript reviewing & editing. AA: Preparing figures 2 & 3, original draft writing, manuscript reviewing & editing. KOM: Study conceptualization and design, manuscript reviewing & editing.NAH: Data analysis, preparing figure 1, original draft writing, manuscript reviewing & editing. All authors have read and approved the final version of the manuscript to be published.

Acknowledgement

The authors are grateful to all participants in this study. Also, the authors thank Professor John C. Rothwell for his manuscript editing and input to improve English language use. Professor Rothwell works in the Sobell Department of Motor Neuroscience and Movement Disorders at the National Hospital for Neurology and Neurosurgery in Queen Square, London, UK.

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Tables 1 to 4 are available in the Supplementary Files section.

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Mechanical thrombectomy of acute ischemic stroke of Medium Sized Vessels (M2 segment of middle cerebral artery occlusion)

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