M1 Segment Of Middle Cerebral Artery Research Articles

Comparing Outcomes of Thrombectomy Versus Intravenous Thrombolysis Based on Middle Cerebral Artery M2 Occlusion Features.

Current evidence provides limited support for the superiority of endovascular thrombectomy (EVT) in patients with M2 segment middle cerebral artery occlusion. We aim to investigate whether imaging features of M2 segment occlusion impact the effectiveness of EVT. We conducted a retrospective cohort study from January 2017 to January 2022, drawing data from the CASE II registry (Computer-Based Online Database of Acute Stroke Patients for Stroke Management Quality Evaluation), which specifically documented patients with acute ischemic stroke presenting with M2 segment occlusion undergoing reperfusion therapy. Patients were stratified into the intravenous thrombolysis (IVT) group (IVT alone) and EVT group (IVT plus EVT or EVT alone). The primary outcome was a modified Rankin Scale score 0 to 2 at 90 days. Secondary outcomes included additional thresholds and distribution of modified Rankin Scale scores, 24-hour recanalization, early neurological deterioration, and relevant complications during hospitalization. Safety outcomes encompassed intracranial hemorrhagic events at 24 hours and mortality at 90 days. Binary logistic regression analyses with propensity score matching were used. Subgroup analyses were performed based on the anatomic site of occlusion, including right versus left, proximal versus distal, dominant/co-dominant versus nondominant, single versus double/triple branch(es), and anterior versus central/posterior branch. Among 734 patients (43.3% were females; median age, 73 years) with M2 segment occlusion, 342 (46.6%) were in the EVT group. Propensity score matching analysis revealed no statistical difference in the primary outcome (odds ratio, 0.860 [95% CI, 0.611-1.209]; P=0.385) between the EVT group and IVT group. However, EVT was associated with a higher incidence of subarachnoid hemorrhage (odds ratio, 6.655 [95% CI, 1.487-29.788]; P=0.004) and pneumonia (odds ratio, 2.015 [95% CI, 1.364-2.977]; P<0.001). Subgroup analyses indicated that patients in the IVT group achieved better outcomes when presenting with right, distal, or nondominant branch occlusion (Pall interaction<0.05). Our study showed similar efficiency of EVT versus IVT alone in acute M2 segment middle cerebral artery occlusion. This suggested that only specific patient subpopulations might have a potentially higher benefit of EVT over IVT alone. URL: https://clinicaltrials.gov; Unique identifier: NCT04487340.

A Case of Severe Lethal Allergic Reaction Caused by Iodixanol After Digital Subtraction Angiography.

Severe lethal allergic reactions triggered by iodixanol following digital subtraction angiography (DSA) are rare. The majority of skin reactions associated with iodixanol were mild, and the prognosis was favorable. Moreover, a case of serious skin adverse events caused by iodixanol has been documented. A 61-year-old woman underwent surgery for a cerebral hemorrhage in another hospital. Upon the surgery, the patient's state of impaired consciousness did not show any improvement. Head computed tomography angiography on admission: right middle cerebral artery M1 segment enlargement, left posterior cerebral artery P2 stenosis. Following undergoing DSA with iodixanol, the patient experienced severe and fatal drug eruptions, which represents a serious and uncommon complication associated with iodixanol. This paper describes the experience in the treatment and nursing of severe allergic reactions. Despite the fact that the patient was discharged automatically and eventually died, there are valuable lessons to be learned from this case that can inform and guide future clinical practices. Iodixanol adverse reactions were rare, and severe fatal adverse reactions were seldom reported. Consequently, the authors conclude that the potential adverse reaction risk of iodixanol contrast agent should be taken into consideration in future endeavors, and the skin and allergy of patients should be monitored following DSA. In an allergy, prompt and proactive treatment is essential to prevent worsening and dissemination.

Rapid identification and prognosis evaluation by dual-phase computed tomography angiography for stroke patients with a large ischemic region in the anterior circulation treated with endovascular thrombectomy.

To investigate the value of dual-phase head-and-neck computed tomography angiography (CTA) in assessing advantages and risks associated with mechanical thrombectomy for stroke with a large ischemic region in the anterior circulation within 6 h of onset. We retrospectively analyzed the data of patients with acute occlusion of the internal carotid artery or middle cerebral artery-M1 segment. Baseline dual-phase CTA was performed for collateral grading using the 4-point visual collateral score (0, 0% filling; 1, >0% and ≤50% filling; 2, >50 and <100% filling; 3, 100% filling). The rates of modified Rankin score (MRS) ≤ 3 at 90 days, any intracranial hemorrhage (ICH) within 48 h, malignant cerebral edema within 24 h, and all-cause 90-day mortality were analyzed. Among the 69 study patients, 15, 26, 17, and 11 patients had collateral grades of 0, 1, 2, and 3, respectively. At 90 days, the MRS was ≤3 in 0, 8.33, 29.41, and 36.36% of patients with grades 0, 1, 2, and 3, respectively. ICH incidence was 73.33, 57.69, 29.41, and 18.18% for grades 0, 1, 2, and 3, respectively, while the incidence of malignant brain edema was 100, 76.92, 35.29, and 0%, respectively. All-cause 90-day mortality was 53.33% for grade 0 and 30.77% for grade 1; no deaths occurred at grades 2 and 3. Collateral grading based on dual-phase CTA enables simple and rapid preoperative evaluation prior to mechanical thrombectomy for acute anterior-circulation stroke with a large ischemic focus, particularly for patients presenting within the 6-h time window.

Distance to thrombus, ischemic lesion volume and clinical outcome after thrombectomy for M1 middle cerebral artery occlusion.

Stroke resulting from occlusion of the middle cerebral artery (MCA) can have devastating consequences, potentially leading to aloss of independence. This study aimed to investigate the relationship between the distance to the thrombus (DT) and both ischemic lesion volume (ILV) and clinical outcomes. We retrospectively evaluated patients with thromboembolic MCA M1 segment occlusion who underwent neurovascular imaging followed by endovascular thrombectomy (EVT) at two comprehensive stroke centers over a3-year period (2018-2020). Preinterventional computed tomography (CT) or magnetic resonance (MR) angiography was used to measure DT, defined as the distance from the carotid‑T bifurcation to the proximal surface of the M1 occlusion. Postinterventional CT or MR imaging was employed to determine the ILV and clinical outcomes were assessed using the modified Rankin scale (mRS) at 3 months. There were 346 patients evaluated. The median DT was 9.4 mm (interquartile range, IQR 6.0-13.7 mm) and the median ILV was 13.9 ml (IQR 2.2-53.1 ml). After adjustment, an increase in DT was associated with adecrease in odds for a larger ILV (odds ratio, OR 0.96, 95% confidence interval, CI 0.92-0.99, p = 0.041). Through this association, more distal thrombi were associated with good clinical outcome (mRS 0-2; clinical outcome available in 282 patients, p = 0.018). The ILV was inversely associated with better clinical outcome OR 0.52 (95% CI 0.40-0.67). Based on the findings, DT was identified as an independent albeit weak predictor for ILV and clinical outcomes in patients with MCA M1 occlusion who underwent EVT.

Primary Angiitis of Central Nervous System related intracranial aneurysm with spontaneous occlusion after immunomodulatory treatment.

Primary Angiitis of the Central Nervous System (PACNS) is an uncommon disease with kaleidoscopic clinical manifestations. Ischemic strokes are commoner than their hemorrhagic counterpart. Intracranial pseudoaneurysms are rarely reported in PACNS cohorts. We hereby describe the case of a 39-year-old female, who presented for evaluation of acute onset of left middle cerebral artery (MCA) ischemic stroke, with cerebral angiogram showing multifocal stenosis and irregularities in intracranial blood vessels with an aneurysm arising from the lenticulostriate branch of the left MCA M1 segment. A diagnosis of probable PACNS was made and patient initiated on immunomodulatory treatment with corticosteroids. 12 weeks follow up neuroimaging studies revealed resolution of the previously described intracranial aneurysm, thereby postulating the possibility of a pseudoaneurysm related to the underlying angiitis.

Flow-diverter stents in intracranial aneurysm treatment: impact on covered cerebral artery branches.

Flow diverter stents (FDSs) have attracted interest for intracranial aneurysm (IA) treatment; however, occlusion of side branches and related complications have been reported. This study aimed to investigate the effects of FDSs in IA management when different branches of intracranial arteries are covered. A cross-sectional study was conducted using PUBMED, Embase, Web of Science, and Cochrane databases to include randomized or nonrandomized comparative-designed studies from January 2000 to August 2022 which reported outcomes of occlusion/narrowing of branches after IA treatment using FDSs. The PRISMA guidelines were used for our report. A random-effects meta-analysis was conducted to pool the outcomes, which included incidence rates of occlusion/narrowing of FDS-covered branches, branch occlusion-related symptoms, obliteration of IAs, and ideal clinical outcomes (modified Rankin Scale score ≤2). The authors identified 57 studies involving 3789 patients with IA managed by FDSs covering different branches. During the median imaging follow-up at 12 months, the IA obliteration rate was satisfactory (>70%) when covering the ophthalmic artery (OA), posterior communicating artery (PComA), anterior choroidal artery (AChoA) or anterior cerebral artery (ACA), but not the middle cerebral artery-M2 segment (MCA-M2; 69.5%; 95% CI: 60.8-77.5%) and posterior inferior cerebellar artery (PICA; 59.1%, 13/22). The overall ideal clinical outcome was observed in 97.4% of patients (95% CI: 95.5-98.9%). Higher rates of occlusion/narrowing of branches were identified when FDSs covered the ACA (66.6%; 95% CI: 45.1-85.3%), PComA (44.3%; 95% CI: 34.2-54.6%), or MCA-M2 (39.2%; 95% CI: 24.5-54.7%); the risks were lower when covering the OA (11.8%; 95% CI: 8.8-15.1%), PICA (6.8%; 95% CI: 1.5-14.5%), and AchoA (0.5%; 95% CI: 0.0-2.9%). The risk of branch occlusion-related complications was low (incidence rate <5%) for each of the six evaluated branches. Acceptable outcomes were identified following treatment of IAs when FDSs were placed across each of the six studied cerebral arteries. Treatment decisions regarding FDS placement across branch arteries should be made with the risk of complications from branch occlusion in mind.

Angiographic Pattern of M1 Stenosis Predicts Territorial Stroke in Patients Receiving Aggressive Medication without Stenting

To evaluate the relationship between different angiographic patterns of middle cerebral artery M1 segment stenosis and related territorial stroke in patients receiving aggressive medical treatment without stenting. We retrospectively reviewed our patient registry database to identify ICAS patients diagnosed by digital subtraction angiography between January 2017 and December 2020 and identified 3 different angiographic patterns (normal, shift, and dilation) in 124 patients with M1 stenosis. The association between these patterns and recurrent ischemic stroke in the M1 territory was analyzed. The rates of recurrent M1 territorial stroke and transient ischemic attack in the normal group, shift group, dilation group and shift-dilation group were 34.5%, 35.0%, 78.3%, and 44.4% respectively. In patients with the shift pattern, the rate of recurrent stroke is significantly higher at a deflection angle ≥9.32° than at a deflection angle <9.32°(P < 0.05). In patients with dilation pattern, the rate of recurrent stroke is significantly higher than patients with non-dilation pattern (72.3% vs. 36.8%, P < 0.05). Angiographic patterns of M1 stenosis may predict recurrent territorial strokes, thus providing a surrogate marker to identify high-risk patients for potential endovascular treatment.

Safety and efficacy of the Low-Profile Visualized Intraluminal Support stent in treating intracranial atherosclerotic stenosis

PurposeThe performance of the Low-Profile Visualized Intraluminal Support (LVIS) stent deployed following balloon angioplasty is unknown in treating intracranial atherosclerotic stenosis, and this study was to investigate the safety and efficacy of the LVIS stent in treating intracranial atherosclerotic stenosis in the middle cerebral artery M1 segment. MethodsThirty-five patients were enrolled with 35 atherosclerotic stenoses at the M1 segment. The stenosis was about 75% in 16 patients, 80% in 15, and 90% in the rest four. The LVIS stent was used to treat these patients. ResultsThe success rate of stenting was 97.1%. The stenting procedure was failed in one patient because of intraprocedural dissection of the stenotic (75%) segment, resulting in a 30-day periprocedural complication rate of 2.9% (1/35). Before stenting, the stenosis rate ranged 75%–90% (mean 78.9%±4.7%), and after stenting, the diameter of the stented segment was significantly (P<0.0001) increased to 1.5–3.4mm (mean 2.1±0.32mm) ranging 68.2%–100% (mean 94.0%±5.8%) of the normal arterial diameter, with the residual stenosis ranging 0–31.8% (median 4.8%, IQR 2.4%–7.3%). Follow-up was performed at 6–20 months (mean 8.5) after stenting. One patient (2.9%) had occlusion of the stented M1 segment with no symptoms, and two patients (5.7%) had slight asymptomatic instent stenosis (40%) at the M1 segment, with the instent restenosis and occlusion rate of 8.6% (3/35). ConclusionThe braided LVIS stent can be safely applied for treatment of intracranial atherosclerotic stenosis in the middle cerebral artery with good safety and efficacy immediately after stenting and at follow-up.

The effect of distal aspiration catheter position on collateral flow in mechanical thrombectomy - an in vitro study.

Endovascular mechanical thrombectomy for ischaemic stroke is one of the most effective treatments. Despite the devices and techniques that have been developed, thrombi are not always successfully retrieved. The incidence of futile reperfusion after successful clot retrieval also remains a major concern. We hypothesise that simply placing an aspiration catheter in the system compromises collateral flow which may have an impact on functional outcomes. An in vitro study was conducted using a physical pulsatile flow model designed in glass to mimic the anterior cerebral circulation with middle cerebral artery M1 segment occlusion. A 5Fr aspiration catheter was positioned at the supra-clinoid internal carotid (SC-ICA), carotid terminus (T-ICA) and M1. For each catheter position, the flow rate through the model's anterior cerebral (ACA) and posterior communicating (PCOM) arteries was measured (no aspiration applied). Our results showed significant mean percentage flow reductions in the ACA and PCOM with the catheter positioned at the SC-ICA (PCOM 59.14% ± 0.93, ACA 59.52% ± 0.82, p < 0.001), T-ICA (PCOM 81.54% ± 0.55, ACA 85.65% ± 1.54) and M1 (PCOM 75.79% ± 0.98, ACA 84.20% ± 0.43) (Mann-Whitney U Test, p < 0.001). These results indicate a significant reduction in collateral flow following the insertion of a wide bore catheter in an in vitro model. In a clinical setting, this could have an impact on patient outcome, particularly in prolonged procedures and those requiring several passes to achieve recanalisation.

Application of high-resolution magnetic resonance vessel wall image in the treatment of M1 segment stenosis of middle cerebral artery

To investigate the application of high-resolution magnetic resonance vessel wall image (HRMR-VWI) in treating middle cerebral artery (MCA) M1 segment stenosis. We retrospectively analyzed preoperative clinical data, imaging data, preoperative evaluation, stent procedure, and postoperative complications in 35 patients with atherosclerotic stenosis of the MCA M1 segment. And the 30-day postoperative mortality and disability and the 12-month restenosis were followed up. There were 21 males and 14 females, with a median age of 55 and a median duration of 1 month from onset to stenting. DSA confirmed that the stenosis locates in the M1 segment, with a stenosis degree of (75.00±17.15) %, a stenosis length of (4.34±1.51) mm, and a blood vessel diameter of (2.25±0.42) mm. After the operation, there was 1 case of death after a craniotomy to remove hematoma+decompression due to reperfusion hemorrhage. There were two technical complications during the procedure (1 case of asymptomatic occlusion of the A1 segment due to the covering of stent at the initial part of A1, 1 case of intraparenchymal hematoma in the temporal lobe due to penetrating distal small blood vessel with guide wire). HRMR-VWI is of great value in observing plaques' location, morphology, and stability. It can improve the safety and effectiveness of stenting treatment of MCA M1 segment stenosis.

Comparison of CT Perfusion Software Packages for Thrombectomy Eligibility.

Computed tomography perfusion (CTP) has played an important role in patient selection for mechanical thrombectomy (MT) in acute ischemic stroke. We aimed to investigate the agreement between perfusion parametric maps of 3 software packages - RAPID (RapidAI-IschemaView), Viz CTP(Viz.ai), and e-CTP(Brainomix) - in estimating baseline ischemic core volumes of near completely/completely reperfused patients. We retrospectively reviewed a prospectively maintained MT database to identify patients with anterior circulation large vessel occlusion strokes (LVOS) involving the internal carotid artery or middle cerebral artery M1-segment and interpretable CTP maps treated during September 2018 to November 2019. A subset of patients with near-complete/complete reperfusion (expanded thrombolysis in cerebral infarction [eTICI] 2c-3) was used to compare the pre-procedural prediction of final infarct volumes. In this analysis of 242 patients with LVOS, RAPID and Viz CTP relative cerebral blood flow (rCBF) < 30% values had substantial agreement (ρ = 0.767 [95% confidence interval [CI] = 0.71-0.81]) as well as for RAPID and e-CTP (ρ = 0.668 [95% CI = 0.61-0.71]). Excellent agreement was seen for time to maximum of the residue function (Tmax ) > 6 seconds between RAPID and Viz CTP (ρ = 0.811 [95% CI = 0.76-0.84]) and substantial for RAPID and e-CTP (ρ = 0.749 [95% CI = 0.69-0.79]). Final infarct volume (FIV) prediction (n = 136) was substantial in all 3 packages (RAPID ρ = 0.744; Viz CTP ρ = 0.711; and e-CTP ρ = 0.600). Perfusion parametric maps of the RAPID, Viz CTP, and e-CTP software have substantial agreement in predicting final infarct volume in near-completely/completely reperfused patients. ANN NEUROL 2023;94:848-855.

Effect of arteriosclerotic intracranial arterial vessel wall enhancement on downstream collateral flow.

The effect of arteriosclerotic intracranial arterial vessel wall enhancement (IAVWE) on downstream collateral flow found in vessel wall imaging (VWI) is not clear. Regardless of the mechanism underlying IAVWE on VWI, damage to the patient's nervous system caused by IAVWE is likely achieved by affecting downstream cerebral blood flow. The present study aimed to investigate the effect of arteriosclerotic IAVWE on downstream collateral flow. The present study recruited 63 consecutive patients at the Second Hospital of Hebei Medical University from January 2021 to November 2021 with underlying atherosclerotic diseases and unilateral middle cerebral artery (MCA) M1-segment stenosis who underwent an magnetic resonance scan within 3 days of symptom onset. The patients were divided into 4 groups according to IAVWE and the stenosis ratio (Group 1, n = 17; Group 2, n = 19; Group 3, n = 13; Group 4, n = 14), and downstream collateral flow was analyzed using three-dimensional pseudocontinuous arterial spin labeling (3D-pCASL) and RAPID software. The National Institutes of Health Stroke Scale (NIHSS) scores of the patients were also recorded. Two-factor multivariate analysis of variance using Pillai's trace was used as the main statistical method. No statistically significant difference was found in baseline demographic characteristics among the groups. IAVWE, but not the stenosis ratio, had a statistically significant significance on the late-arriving retrograde flow proportion (LARFP), hypoperfusion intensity ratio (HIR), and NIHSS scores ( F = 20.941, P <0.001, Pillai's trace statistic = 0.567). The between-subject effects test showed that IAVWE had a significant effect on the three dependent variables: LARFP ( R2 = 0.088, F = 10.899, P = 0.002), HIR ( R2 = 0.234, F = 29.354, P <0.001), and NIHSS ( R2 = 114.339, F = 33.338, P <0.001). Arteriosclerotic IAVWE significantly reduced downstream collateral flow and affected relevant neurological deficits. It was an independent factor affecting downstream collateral flow and NIHSS scores, which should be a focus of future studies. ChiCTR.org.cn, ChiCTR2100053661.

The incidence of medium vessel occlusions: a population-based study.

The incidence of medium vessel occlusion (MeVO) is not well known. The objective of our study is to perform a population-based assessment to estimate the incidence of MeVOs. Consecutive patients from Olmsted County, Minnesota who presented for acute ischemic stroke seen at Mayo Clinic Hospital from 1/1/2018 to 12/31/2020 who were found to have a MeVO were included in this study. MeVO was defined as occlusion at or beyond the level of the middle cerebral artery M2 segment, anterior cerebral artery A2 segment, posterior cerebral artery P1 segment, and cerebellar arteries. Census data for Olmsted County was obtained from the United States Census Bureau from the year 2020. A total of 1,718 patients were screened for the study, 77 patients fulfilled inclusion criteria to be included in the study. Presenting NIHSS was 9 (± 7). The population of Olmsted County was estimated to be 162,847. The incidence rate for MeVO was 16 cases (95% CI 12-19) per 100,000 people per year. Based on estimates of the US population in 2020 of 331,449,281 people, we estimate there are 52,236 (95% CI 40,635-64,002) new cases of MeVOs per year. As the only stroke center in Olmsted County, we have been able to estimate the incidence of ischemic stroke due to MeVO. While the incidence of MeVOs is less than both large and small vessel occlusions, they still represent a significant proportion of strokes with significant morbidity and mortality that would benefit from further studies in both acute intervention and prevention.

Anatomical distribution and clinical significance of middle cerebral artery M2 segment vessel occlusions and its cortical branches in acute ischaemic stroke patients

BackgroundCharacterisation of anatomical distribution and the clinical impact of middle cerebral artery M2 (MCA-M2) segment occlusion and its subsequent cortical branches (CBs) in acute ischaemic stroke patients (AIS).MethodsRetrospective, monocentric study...

Middle Cerebral Artery Dissection: A Report of Two Cases With Treatments and Outcomes

In the present report, we describe two cases of right-sided M1 segment middle cerebral artery dissection in a 51-year-old Asian female and in a 28-year-old Caucasian male patient with no previous history of ischemic stroke or known intracranial atherosclerosis presenting with acute unilateral headache progressing to severe multifocal hemispheric infarction with nearly complete one-sided motor paralysis. In both patients, a middle cerebral artery dissection was detected on angiography; they were given exclusively medical therapy: patient 1 was not eligible to reperfusive therapies and was treated with a three-month course of acetylsalicylic acid and clopidogrel combined with low-dose enoxaparin, while patient 2 was initially treated with intravenous alteplase with no hemorrhagic complications and was later shifted to single antiplatelet therapy. Despite an initial worsening of clinical severity and an extensive ischemic lesion in both patients, neurologic function improved over time, eventually allowing recovery of unaided gait. Therefore, in the absence of signs of hemorrhage, intravenous thrombolysis or dual antiplatelet regimens could be considered in strokes related to middle cerebral artery dissection.

Functional and technical outcomes in acute ischemic stroke patients with hyperdense middle cerebral artery sign treated with endovascular thrombectomy.

The hyperdense middle cerebral artery sign (HMCAS) is observed in a proportion of patients with acute ischemic stroke (AIS). This sign reflects the presence of an intravascular thrombus rich in red blood cells. Several studies have demonstrated that HMCAS increases the risk of poor outcomes in AIS patients treated with IV thrombolysis or no reperfusion therapy; however, whether HMCAS predicts a poor outcome in patients treated with endovascular thrombectomy (EVT) is less clear. We aimed to evaluate the functional outcome by the modified Rankin scale (mRS) at 90 days and technical challenges in patients with HMCAS undergoing EVT. We studied 143 consecutive AIS patients with middle cerebral artery M1 segment or internal carotid artery + M1 occlusions who underwent EVT. There were 73 patients (51%) with HMCAS. Patients with HMCAS had a higher frequency of cardioembolic stroke (p = 0.038); otherwise, no other baseline difference was observed. No differences in functional outcomes (mRS) at 90 days (p = 0.698), unfavorable outcomes (mRS > 2) (p = 0.929), frequency of symptomatic intracranial hemorrhage (p = 0.924), and mortality (mRS-6) (p = 0.736) were observed between patients with and without HMCAS. In patients with HMCAS, EVT procedures were 9 min longer, requiring a higher number of passes (p = 0.073); however, optimal recanalization scores (modified thrombolysis in cerebral infarction: 2b-3) were equally achieved by both groups. Patients with HMCAS treated with EVT do not have a worse outcome at 3 months compared with no-HMCAS patients. Patients with HMCAS required a greater number of thrombus passes and longer procedure times.

Successful mechanical thrombectomy in acute bilateral M1 middle cerebral artery occlusion: a case report and literature review

BackgroundAcute bilateral occlusion of the middle cerebral artery (MCA) is a very rare condition, and most cases are accompanied by a poor prognosis. However, mechanical thrombectomy (MT) for bilateral MCA is challenging. Here, we report a case of acute unilateral MCA occlusion with sequential acute occlusion of the bilateral MCA during intravenous thrombolysis (IVT). We urgently performed bilateral MT of the MCA and effective recanalization.Case presentationThe patient is a 73-year-old man who complained of a sudden adverse influence on speech and an inability to move his left limb for 2 h. He had a history of paroxysmal atrial fibrillation, but had never used any anticoagulants before. Head and neck computed tomography angiography (CTA) showed embolism in the right M1 MCA. During intravenous alteplase thrombolytic therapy, the patient suddenly became unconscious. Cerebral angiography showed occlusion of the M1 segment of the bilateral MCA in the patients. MT of the bilateral MCA was performed using a combination of a stent retriever and an aspiration catheter with mTici 3 revascularization. On the second day, the patient became conscious, although he had remaining symptoms of speech insufficiency and weakness of the left limb. The mRS score was 2 90 days after the operation.ConclusionsAcute bilateral occlusion of the M1 segment of the MCA is extremely rare and is accompanied by high morbidity and high mortality. Intravenous alteplase thrombolysis can increase the risk of atrial thrombus shedding in patients with atrial fibrillation, so patients with acute bilateral MCA occlusion in the M1 segment chose direct MT or bridging therapy, which remains controversial, and the sequence of MT remains to be discussed. Nevertheless, early endovascular treatment can decrease the morbidity and mortality of such patients.

Safety and Efficacy of MCA‐M2 Thrombectomy in Delayed Time Window: A Propensity Score Analysis From the STAR Registry

Background Mechanical thrombectomy of middle cerebral artery M2 segment occlusion of the middle cerebral artery has reported safety and efficacy in recent post‐hoc and observational studies. However, there is no known benefit of mechanical thrombectomy for patients with M2 segment occlusions in the delayed time window (&gt;6 hours). Methods The Stroke Thrombectomy and Aneurysm Registry (STAR) is a prospective, multicenter, nonrandomized observational study registry for acute ischemic stroke thrombectomy and aneurysm treatment. We analyzed all patients who underwent mechanical thrombectomy within the late time window (&gt;6 hours from symptom onset) involving isolated M2 occlusions. We used propensity score matching to select a comparison group of patients who underwent mechanical thrombectomy for M1 occlusion in the same time window. Results Of 1083 consecutive patients analyzed, propensity matching yielded 180 well matched M1 and M2 pairs. Baseline demographics were well balanced between the groups (M1 and M2). Alberta stroke program early CT score (7.6±1.7 versus 8.3±1.5; P &lt;0.001) was higher in the M2 group. There was a trend towards less complete recanalization (Thrombolysis in Cerebral Infarction 3) 46.1% versus 39.9% ( P =0.053) in the middle cerebral artery M2 segment cohort. However, successful recanalization (Thrombolysis in Cerebral Infarction 2b‐3) was better in middle cerebral artery M2 segment cohort (85% versus 90.5%; P =0.053). Postprocedural asymptomatic hemorrhage rates were similar (29.4% versus 27.8%; P =0.816), but symptomatic hemorrhage rates were higher in the M1 group (7.2% versus 2.2%; P =0.047). Rates of good clinical outcome (modified Rankin scale 0–2) were similar at final follow‐up (43.9% versus 46.7%; P =0.672). The overall mortality was also similar between the cohorts (12.8% versus 13.9%; P =0.877). Conclusion In our analysis of the Stroke Thrombectomy and Aneurysm Registry, M2 occlusions not only achieved similar rates of recanalization and good functional outcome compared with M1 occlusions in a delayed time window (6–24 hours from last normal) but also had less symptomatic intracranial hemorrhage.

Modified treatment in cerebral ischemia 1 versus modified treatment in cerebral ischemia 0 before endovascular stroke treatment in middle cerebral artery’s M1-occlusion: Predictor for revascularization success and outcome?

Background Little is known about the implications for revascularization success of target vessel occlusions (TVOs) with persisting antegrade perfusion before initiation of endovascular stroke treatment (EST) (modified treatment in cerebral ischemia (mTICI 1)) compared to a complete occlusion (mTICI 0). Here, we compared these two states of TVO. Methods Retrospective, single-center analysis of patients treated for M1-segment middle cerebral artery (MCA) occlusion with EST from January 2015 until May 2020 in a tertiary stroke center. Primary study endpoint was successful recanalization (mTICI 2c-3) after one thrombectomy attempt. Secondary endpoints were clinical outcome (modified Rankin Scale (mRS) 90 days after stroke onset), complication rate, and rate of underlying atherosclerotic disease. The two study groups were compared in univariate analysis including patient characteristics and procedural details. Results In this study, 422/581 patients (72.6%) presented with complete M1-occlusion compared to 159/581 (27.4%) with incomplete M1-occlusion. Neither did the recanalization success rate differ between the study groups nor the rate of complications (mTICI 0: 2.4%, mTICI 1: 0.6%, p = 0.304) or underlying atherosclerotic disease. Patients with incomplete initial occlusion showed a lower mRS at discharge (median interquartile range (IQR) mTICI 0: 4 (3–5) vs. mTICI 1: 3 (2–6), p = 0.014), but a comparable mRS 90 days after stroke onset (mTICI 0: 3 (2–6) vs. mTICI 1: 4 (2–6), p = 0.479). Conclusion Complete M1-occlusions (mTICI 0) and incomplete occlusions (mTICI 1) show the same recanalization success, comparable complication rate, and clinical outcome as well as the same rate of underlying atherosclerotic disease. Thus, incomplete M1-occlusions do not allow for an individualized interventional approach.

The diagnostic performance of artificial intelligence algorithms for identifying M2 segment middle cerebral artery occlusions: A systematic review and meta-analysis

BackgroundArtificial intelligence (AI)-based algorithms have been developed to facilitate rapid and accurate computed tomography angiography (CTA) assessment in proximal large vessel occlusion (LVO) acute ischemic stroke, including internal carotid artery and M1 occlusions. In clinical practice, however, the detection of medium vessel occlusion (MeVO) represents an ongoing diagnostic challenge in which the added value of AI remains unclear. PurposeTo assess the diagnostic performance of AI platforms for detecting M2 occlusions. MethodsStudies that report the diagnostic performance of AI-based detection of M2 occlusions were screened, and sensitivity and specificity data were extracted using the semi-automated AutoLit software (Nested Knowledge, MN) platform. STATA (version 16 IC; Stata Corporation, College Station, Texas, USA) was used to conduct all analyses. ResultsEight studies with a low risk of bias and significant heterogeneity were included in the quantitative and qualitative synthesis. The pooled estimates of sensitivity and specificity of AI platforms for M2 occlusion detection were 64% (95% CI, 53 to 74%) and 97% (95% CI, 84 to 100%), respectively. The area under the curve (AUC) in the SROC curve was 0.79 (95% CI, 0.74 to 0.83). ConclusionThe current performance of the AI-based algorithm makes it more suitable as an adjunctive confirmatory tool rather than as an independent one for M2 occlusions. With the rapid development of such algorithms, it is anticipated that newer generations will likely perform much better.