M1 Occlusion Research Articles

FLAIR vascular hyperintensity combined with asymmetrical prominent veins in acute anterior circulation ischemic stroke: prediction of collateral circulation and clinical outcome

BackgroundTo investigate the value of fluid-attenuated inversion recovery vascular hyperintensity (FVH) within asymmetrical prominent veins sign (APVS) on susceptibility-weighted imaging predicting collateral circulation and prognosis in patients with acute anterior circulation ischemic stroke.MethodPatients with severe stenosis or occlusion of ICA or MCA M1, who underwent MRI within 72 h from stroke onset were reviewed. The Alberta Stroke Program Early CT Score was used to evaluate the volume of infarction on DWI, the degree of FVH and APVS. Spearman correlation analysis was used to evaluate the correlation between FVH and APVS. All patients were divided into the good prognosis group and the poor prognosis group according to the score of the modified ranking scale (mRS) 90 days after the stroke. Logistic regression analysis was used to explore the relationship between FVH and APVS and functional prognosis, while receiver operating characteristic (ROC) curves were plotted to assess the value of FVH and APVS in predicting prognosis.ResultsSpearman correlation analysis revealed moderate positive correlations between FVH and APVS (r = 0.586, P < 0.001). The poor prognosis group had a higher rate of a history of atrial fibrillation, a larger cerebral infarction volume, a higher NIHSS score at admission, and a higher FVH and APVS score compared with the good prognosis group (all P < 0.05). A further logistic regression indicated that the NIHSS score, cerebral infarction volume, FVH and APVS were independent risk factors for a poor functional prognosis. In terms of FVH, APVS, alone and their combination for the diagnosis of poor prognosis, the sensitivity, specificity, area under the ROC curve (AUC), and 95% confidence interval (CI) were 86.8%, 83.3%, 0.899 (95% CI 0.830–0.968); 60.5%, 93.7%, 0.818 (95% CI 0.723–0.912); 86.8%, 89.6%, 0.921 (95% CI 0.860–0.981), respectively.ConclusionThe presence of FVH and APVS can provide a comprehensive assessment of collateral circulation from the perspective of veins and arteries, and the correlation between the two is positively correlated. Both of them were independent risk factors for poor prognosis, their combination is complementary and can improve the predictive value.

Cost-Effectiveness of Endovascular Thrombectomy in M2 Occlusion Stroke: Real-World Experience Versus Clinical Trials.

This study sought to establish the cost-effectiveness of endovascular thrombectomy (EVT) in M2 occlusions compared with patients who did not have EVT using both real-world and clinical trial evidence. The effectiveness of EVT in M2 occlusions was informed by the International Stroke Perfusion Imaging Registry (INSPIRE, real-world data for a wide range of strokes) and HERMES collaboration, trial data. Patients who received EVT and non-EVT treatment from INSPIRE were matched according to baseline characteristics. A Markov model with 7 health states defined by the 3-month modified Rankin scale (mRS) was constructed. Endovascular thrombectomy and non-EVT-treated patients in real-world, and clinical trials were run through the Markov model separately to generate the results from a limited societal perspective. National statistics and published literature informed the long-term probability of recurrent stroke, mortality, costs of management post-stroke, non-medical care, and nursing home care. A total of 83 (42 EVT and 41 non-EVT) patients were matched of 278 (45 EVT and 233 non-EVT) patients in INSPIRE who had M2 occlusion stroke at presentation. The long-term simulation estimated that offering EVT to M2 occlusion stroke patients was associated with greater benefits (5.48 EVT vs 5.24 non-EVT quality-adjusted life year [QALY]) and higher costs (A$133 457 EVT vs A$126 127 non-EVT) compared with non-EVT treatment in real-world from a limited societal perspective. The incremental cost-effectiveness ratio (ICER) of EVT in real-world was A$29 981 (€19 488)/QALY. The analysis using the data from HERMES collaboration yielded consistent results for the EVT patients. Comparison with real-world cost-effectiveness analyses of EVT in internal carotid artery/middle cerebral artery-M1 (ICA/MCA-M1) occlusion suggested a potential reduced QALY gains and increased ICER in M2 occlusions. Our study suggested that the benefits gained from EVT in M2 occlusion stroke in the real-world were similar to that derived from the clinical trials. The clinical and cost benefits from EVT appeared to be reduced in M2 compared with that from the ICA/MCA-M1 occlusions. Our study has provided valuable insights into the clinical significance of endovascular therapy (EVT) in the context of M2 occlusion stroke within a real-world setting. It is noteworthy that our findings indicate that the benefits obtained from EVT in M2 occlusion stroke closely align with those observed in controlled clinical trials. However, it is essential to recognize that there is a reduction in the clinical and cost-related advantages when comparing M2 occlusions to more proximal ICA/MCA-M1 occlusions.

Association between blood pressure and endovascular treatment outcomes differs by baseline perfusion and reperfusion status

We hypothesized that the association between BP and endovascular treatment (EVT) outcomes would differ by baseline perfusion and recanalization status. We identified 388 ICA or M1 occlusion patients who underwent EVT ≤ 24 h from onset with successful recanalization (TICI ≥ 2b). BP was measured at 5-min intervals from arrival and during the procedure. Systolic BPs (SBP) were summarized as dropmax (the maximal decrease over two consecutive measurements), incmax (the maximal increase), mean, coefficient of variation (cv), and standard deviation. Adequate baseline perfusion was defined as hypoperfusion intensity ratio (HIR) ≤ 0.5; infarct proportion as the volume ratio of final infarcts within the Tmax > 6 s region. In the adequate perfusion group, infarct proportion was closely associated with SBPdropmax (β ± SE (P-value); 1.22 ± 0.48, (< 0.01)), SBPincmax (1.12 ± 0.33, (< 0.01)), SBPcv (0.61 ± 0.15 (< 0.01)), SBPsd (0.66 ± 0.08 (< 0.01)), and SBPmean (0.71 ± 0.37 (0.053) before recanalization. The associations remained significant only in SBPdropmax, SBPincmax, and SBPmean after recanalization. SBPincmax, SBPcv and SBPsd showed significant associations with modified Rankin Scale score at 3 months in the pre-recanalization period. In the poor perfusion group, none of the SBP indices was associated with any stroke outcomes regardless of recanalization status. BP may show differential associations with stroke outcomes by the recanalization and baseline perfusion status.

Relevance of NIHSS subitems for best revascularization therapy in minor stroke patients with large vessel occlusion: an observational multicentric study.

The best management of acute ischemic stroke patients with a minor stroke and large vessel occlusion is still uncertain. Specific clinical and radiological data may help to select patients who benefit from Endovascular Therapy (EVT). We aimed to evaluate the relevance of NIHSS subitems for predicting potential benefit of EVT after intravenous thrombolysis (IVT)("bridging treatment") versus IVT alone. We extracted demographic, clinical, risk factor, radiological, revascularization and outcome data from consecutive patients with M1 or proximal M2 middle cerebral artery occlusion and admission NIHSS scores of 0-5 points treated with IVT+/-EVT between May 2005 and March 2021 from nine prospectively-constructed stroke registries from seven French and two Swiss comprehensive stroke centers. Adjusted interaction analyses were performed between admission NIHSS subitems and revascularization modality for two primary outcomes at 3 months: non-excellent functional outcome (mRS 2-6) and difference in NIHSS score between 3 months and admission RESULTS: Of the 533 patients included (median age 68.2 years, 46% women, median admission NIHSS score 3), 136 (25.5%) patients initially received bridging therapy and 397 (74.5%) IVT alone. Adjusted interaction analysis revealed that only facial palsy on admission was more frequently associated with excellent outcome in patients treated by IVT alone versus bridging therapy (OR=0.47, 95%CI=0.24-0.91, p=0.013). Regarding NIHSS-difference at 3 months, no single NIHSS subitems interacted with the type of revascularization. This retrospective multicenter analysis found that NIHSS subitems at admission had little value in predicting patients who might benefit from bridging therapy as opposed to IVT alone. Further research is needed to identify better markers for selecting EVT responders with minor strokes.

Duration and accuracy of automated stroke CT workflow with AI-supported intracranial large vessel occlusion detection

The Automation Platform (AP) is a software platform to support the workflow of radiologists and includes a stroke CT package with integrated artificial intelligence (AI) based tools. The aim of this study was to evaluate the diagnostic performance of the AP for the detection of intracranial large vessel occlusions (LVO) on conventional CT angiography (CTA), and the duration of CT processing in a cohort of acute stroke patients. The diagnostic performance for intracranial LVO detection on CTA by the AP was evaluated in a retrospective cohort of 100 acute stroke patients and compared to the diagnostic performance of five radiologists with different levels of experience. The reference standard was set by an independent neuroradiologist, with access to the readings of the different radiologists, clinical data, and follow-up. The data processing time of the AP for ICH detection on non-contrast CT, LVO detection on CTA, and the processing of CTP maps was assessed in a subset 60 patients of the retrospective cohort. This was compared to 13 radiologists, who were prospectively timed for the processing and reading of 21 stroke CTs. The AP showed shorter processing time of CTA (mean 60 versus 395 s) and CTP (mean 196 versus 243–349 s) as compared to radiologists, but showed lower sensitivity for LVO detection (sensitivity 77% of the AP vs mean sensitivity 87% of radiologists). If the AP would have been used as a stand-alone system, 1 ICA occlusion, 2 M1 occlusions and 8 M2 occlusions would have been missed, which would be eligible for mechanical thrombectomy. In conclusion, the AP showed shorter processing time of CTA and CTP as compared with radiologists, which illustrates the potential of the AP to speed-up the diagnostic work-up. However, its performance for LVO detection was lower as compared with radiologists, especially for M2 vessel occlusions.

AI-support for the detection of intracranial large vessel occlusions: One-year prospective evaluation

PurposeFew studies have evaluated real-world performance of radiological AI-tools in clinical practice. Over one-year, we prospectively evaluated the use of AI software to support the detection of intracranial large vessel occlusions (LVO) on CT angiography (CTA). MethodQuantitative measures (user log-in attempts, AI standalone performance) and qualitative data (user surveys) were reviewed by a key-user group at three timepoints. A total of 491 CTA studies of 460 patients were included for analysis. ResultsThe overall accuracy of the AI-tool for LVO detection and localization was 87.6%, sensitivity 69.1% and specificity 91.2%. Out of 81 LVOs, 31 of 34 (91%) M1 occlusions were detected correctly, 19 of 38 (50%) M2 occlusions, and 6 of 9 (67%) ICA occlusions. The product was considered user-friendly. The diagnostic confidence of the users for LVO detection remained the same over the year. The last measured net promotor score was −56%. The use of the AI-tool fluctuated over the year with a declining trend. ConclusionsOur pragmatic approach of evaluating the AI-tool used in clinical practice, helped us to monitor the usage, to estimate the perceived added value by the users of the AI-tool, and to make an informed decision about the continuation of the use of the AI-tool.

Comparison of the Contour Neurovascular System and Woven EndoBridge device for treatment of wide-necked cerebral aneurysms at a bifurcation or sidewall.

The authors compared the Contour Neurovascular System (Contour) with the Woven EndoBridge (WEB) device for the treatment of wide-necked cerebral aneurysms at a bifurcation or sidewall. Prospective clinical and radiological data were collected for all patients treated with either the Contour or WEB at a tertiary university hospital from May 2018 to June 2022. In patients who had at least 3 months of follow-up data available (median patient age 60.0 [IQR 51.8-67.0] years, male/female ratio 1:1.4), the authors compared 40 aneurysms in 34 patients treated with the Contour and 30 aneurysms in 30 patients treated with the WEB. Overall, 26 middle cerebral artery, 24 anterior communicating artery, 9 basilar artery tip, 4 posterior communicating artery, 4 internal carotid artery, 1 anterior cerebral artery, 1 posterior inferior cerebellar artery, and 1 superior cerebellar artery aneurysm were treated. In the Contour cohort, complete occlusion at last follow-up was achieved for 30 aneurysms (75%) and a small neck remnant was seen in 6 aneurysms (15%), summing up to an adequate occlusion rate of 90%. One aneurysm (2.5%) had to be retreated, and 1 symptomatic thromboembolic event (2.5%) was observed with complete remission at discharge. Three adjunctive stents (10%) had to be used due to branch occlusion. In the WEB cohort, adequate occlusion was also seen in 90% of aneurysms (complete occlusion in 19 [63.3%] and remnant neck in 8 [26.7%], with a retreatment rate of 20%). Four WEBs (13.3%) needed additional stent placement due to device protrusion into a branch, 2 asymptomatic thromboembolic events (6.7%) were noted, and 1 major ischemic event (3.3%) due to M2 occlusion was noted. One patient treated with the WEB died between follow-ups of causes unrelated to the aneurysm, treatment, or device. Time from first measurement to deployment and thus total treatment time was significantly shorter in the Contour group (p = 0.004), regardless of whether a prior angiogram was available for aneurysm measurement and device sizing. Results for the Contour were promising, although longer follow-up is necessary to draw more solid conclusions on the utility and risk profile of this new device compared with the already widely used WEB device. Adequate occlusion at last follow-up was the same for both devices, whereas the probability of complete occlusion at last follow-up was significantly higher for the Contour, and the WEB showed a significantly higher retreatment rate. Median deployment times were significantly shorter with the Contour than the WEB.

Circle of Willis integrity in acute middle cerebral artery occlusion: does the posterior communicating artery matter?

BackgroundCollateral circulation is an important determinant of outcome in people with acute ischemic stroke due to large vessel occlusion (LVO).ObjectiveTo explore the impact of the circle of Willis (CW) anatomical...

Effect of race/ethnicity on arterial recanalization following intravenous thrombolysis in acute ischemic stroke patients

IntroductionSeveral reports have identified that clinical outcomes such as death or disability in acute ischemic stroke (AIS) patients following intravenous (IV) tissue plasminogen activator (tPA) treatment can vary according to race and ethnicities. We determined the effect of race/ethnicity on rates of arterial recanalization in AIS patients with large vessel occlusion (LVO) after IV tPA. MethodsWe analyzed 234 patients with LVO detected on computed tomographic angiography (CTA) who received IV tPA and subsequently underwent angiography for potential thrombectomy. The primary occlusion sites on CTA and digital subtracted angiography (DSA) were compared and a score was given to the level of recanalization with values ranging from 1 (complete recanalization), 2 (partial recanalization), or 3 (no recanalization).The effect of race/ethnicity were assessed for predicting vessel recanalization using the covariates of age, gender, time since stroke onset, tPA dose received, NIHSS (National Institute of Health Stroke Scale) score at baseline, and location of the occlusion, using logistic regression analysis. ResultsFive patients (2.1%) were Hispanic or Latino, 8 (3.4%) Asian, 24 (10.3%) African American, and 197 (84.2%) White. A total of 50% had a distal ICA/proximal M1 occlusion, 20% distal M1 occlusion, and 16% single M2 occlusion. At the primary occlusion site, 44 (18.8%) had complete recanalization on post IV tPA angiogram, 17 (7.3%) had partial recanalization, and 165 (70.5%) had no recanalization. We did not find any association between race/ethnicity and vessel recanalization post IV tPA (Nonwhite combined [OR=1.49, p=0.351]; Asian [OR=1.460, p=0.650]; African American [OR=1.508, p=0.415]; White [OR=0.672, p=0.351]; ethnicity (Hispanic or Latino) [OR= 1.008, p=0.374]); Occlusion location (OR=0.189, p<0.001). Final TICI scores and mRS at 90 days were similar among the different groups. ConclusionApproximately 19% of patients had complete recanalization after IV tPA, but race and ethnicity did not seem to have an effect on arterial recanalization. Arterial recanalization was only affected by location of occlusion.

Thrombectomy for M2 Occlusions: Predictors of Successful and Futile Recanalization.

Patient-specific factors associated with successful recanalization in mechanical thrombectomy (MT) have been evaluated for acute ischemic stroke with large vessel occlusion. However, MT for M2 occlusions is still a matter of debate, and predictors of successful and futile recanalization have not been assessed in detail. We sought to identify predictors of recanalization success in patients with M2 occlusions undergoing MT based on large-scale clinical data. All patients prospectively enrolled in the German Stroke Registry (May, 2015 to December, 2021) were screened (N=13 082). Inclusion criteria for the complete case analysis were isolated M2 occlusions. Standard descriptive statistics and multivariable logistic regression analysis were used to identify factors associated with successful recanalization (Thrombolysis in Cerebral Infarction [TICI]≥2b), complete recanalization (TICI=3) and futile recanalization (TICI≥2b with 90-day modified Rankin Scale [mRS] score >2). One thousand two hundred ninety-four patients were included, thereof 439 (33.9%) with TICI=2b and 643 (49.7%) with TICI=3. Five hundred sixty-nine (44%) patients had good functional outcome (90-day mRS score ≤2). In multivariable logistic regression, general anesthesia (adjusted odds ratio [aOR], 1.47 [95% CI, 1.05-2.09]; P<0.05) was associated with higher probability of TICI≥2b while intraprocedural change from local to general anesthesia (aOR, 0.49 [0.26-0.95]; P<0.05) and higher pre-mRS (aOR, 0.75 [0.67-0.85]; P<0.001) lowered probability of successful recanalization. Futile recanalization was associated with higher age (aOR, 1.05 [1.04-1.07]; P<0.001), higher prestroke mRS (aOR, 3.12 [2.49-3.91]; P<0.001), higher NIHSS at admission (aOR, 1.11 [1.08-1.14]; P<0.001), diabetes (aOR, 1.96 [1.38-2.8]; P<0.001), higher number of passes (aOR, 1.29 [1.14-1.46]; P<0.001), and adverse events (aOR, 1.82 [1.2-2.74]; P<0.01). Higher Alberta Stroke Program Early CT Score (aOR, 0.85 [0.76-0.94]; P<0.01) and IV thrombolysis (aOR, 0.71 [0.52-0.97]; P<0.05) reduced risk of futile recanalization. In patients with M2 occlusions, successful recanalization was significantly associated with general anesthesia and low prestroke mRS, while intraprocedural change from conscious sedation to general anesthesia increased risk of unsuccessful recanalization, presumably caused by difficult anatomy and movement of patients in these cases. Futile recanalization was associated with severe prestroke mRS, comorbidity diabetes, number of passes and adverse events during treatment. IV thrombolysis reduced the risk of futile recanalization.

Predictors of Angiographic Outcome After Failed Thrombectomy for Large Vessel Occlusion: Insights from the Stroke Thrombectomy and Aneurysm Registry.

Mechanical thrombectomy failure (MTF) occurs in approximately 15% of cases. To investigate factors that predict MTF. This was a retrospective review of prospectively collected data from the Stroke Thrombectomy and Aneurysm Registry. Patients who underwent mechanical thrombectomy (MT) for large vessel occlusion (LVO) were included. Patients were categorized by mechanical thrombectomy success (MTS) (≥mTICI 2b) or MTF (<mTICI 2b). Demographics, pretreatment, and treatment information were included in a univariate (UVA) and multivariate (MVA) analysis for prediction of MTF. A total of 6780 patients were included, and 1001 experienced anterior circulation MTF. Patients in the MTF group were older (73 vs 72, P = .044) and had higher poor premorbid modified Rankin Scale (mRS) (10.8% vs 8.4%, P = .017). Onset to puncture time was greater in the MTF group (273 vs 260 min, P = .08). No significant differences were found between the access site, use of balloon guide catheter, frontline technique, or first-pass devices between the MTF and MTS groups. More complications occurred in the MTF group (14% vs 5.8%), including symptomatic intracerebral hemorrhage (9.4% vs 6.1%) and craniectomies (10% vs 2.8%) ( P < .001). On UVA, age, poor pretreatment mRS, increased number of passes, and increased procedure time were associated with MTF. Internal carotid artery, M1, and M2 occlusions had decreased odds of MTF. Poor preprocedure mRS, number of passes, and procedure time remained significant on MVA. A subgroup analysis of posterior circulation LVO revealed that number of passes and total procedure time correlated with increased odds of MTF ( P < .001) while rescue stenting was associated with less odds of MTF (odds ratio 0.20, 95% CI 0.06-0.63). Number of passes remained significant on MVA of posterior circulation occlusion subgroup analysis. Anterior circulation MTF is associated with more complications and worse outcomes. No differences were found between techniques or devises used for the first pass during MT. Rescue intracranial stenting may decrease the likelihood of MTF for posterior circulation MT.

Disconnection of a stent retriever's pushwire caught by an accordion-like deformed aspiration catheter during mechanical thrombectomy: illustrative case.

In mechanical thrombectomy for acute large vessel occlusion, a combined technique of using both a stent retriever and an aspiration catheter has been widely used. The authors report a case in which a stent retriever's pushwire and a microcatheter were caught and disconnected by an accordion-like deformed aspiration catheter. A 74-year-old man underwent mechanical thrombectomy for a left M1 occlusion. A stent retriever was deployed from the left M2 to the left distal M1, and an aspiration catheter was advanced to the left distal M1. When the stent retriever and microcatheter were pulled into the aspiration catheter at the distal M1 without releasing the deflection, traction resistance of the stent retriever occurred, and the aspiration catheter contracted and deformed like an accordion distal to the tip of the guiding catheter. The stent retriever's pushwire and the microcatheter were caught and disconnected. When a stent retriever is pulled into a flexible aspiration catheter in a case with vascular tortuosity, it may be caught by an accordion-like deformed aspiration catheter and disconnected. It is necessary to release the deflection of the aspiration catheter once traction resistance of the stent retriever and deflection of the aspiration catheter occur.

E.2 Predictors of successful endovascular thrombectomy for M2 occlusion in acute ischemic stroke

Background: There remains lack of data in regards to factors influencing successful endovascular reperfusion of isolated occlusion of the M2 segment of the middle cerebral artery (MCA). In this study, we set out to investigate the variables that affect the successful endovascular reperfusion of isolated M2 segment occlusion. Methods: M2 segment occlusion was defined as isolated clot anywhere within the M2 segment of the MCA. A prediction model of successful endovascular reperfusion defined as modified Thrombolysis in Cerebral Ischemia (mTICI) score of 2b, 2c and 3 and unsuccessful endovascular reperfusion defined as mTICI score of 0, 1 and 2a was developed from demographics (age, sex) , clinical factors (NIHSS at the time of presentation to hospital), imaging characteristics (ASPECTS, ICA occlusion, presence of Intracranial arterial disease (ICAD), computed tomography perfusion (CTP)-based ischemic core and mismatch volume estimation), and treatment (alteplase/tenecteplase use and periprocedural complications) variables from 64 patients who underwent endovascular thrombectomy (EVT) at Kingston Health Science Centre between December 24, 2018 and October 18, 2022. Results: The only statistical significant predictor of successful endovascular reperfusion was CTP-based ischemic core volume (smaller core volume) (p&lt;0.05). Conclusions: The CTP-based ischemic core volume is the most important predictor of successful endovascular reperfusion for M2 occlusion.

Improved catheter delivery for aspiration thrombectomy using Tenzing 7 ledge reducing catheter and FreeClimb 70.

Previous comparative mechanical thrombectomy device trials reported a substantial crossover rate from first-line aspiration to stent-retriever thrombectomy. A specialized delivery catheter may help track large-bore aspiration catheters to target occlusions. We report our multicenter experience of aspiration thrombectomy of intracranial large vessel occlusions using the FreeClimbTM 70 and Tenzing® 7 delivery catheter (Route 92, San Mateo, CA). After local Institutional Review Board approval, we retrospectively reviewed the clinical, procedural, and imaging data of patients who underwent mechanical thrombectomy with the FreeClimb 70 and Tenzing 7. FreeClimb 70 was successfully delivered using Tenzing 7 to target occlusion in 30/30 (100%) patients (18 M1, 6 M2, 4 ICA-terminus, and 2 basilar artery occlusions), without the use of a stent-retriever for anchoring. In 21/30 (70%) cases, a leading microwire was not needed to advance the Tenzing 7 to the target. Median (interquartile range) time from groin puncture to first pass was 12 (interquartile range 8-15) minutes. Overall first pass effect, or first pass effect (modified thrombolysis in cerebral ischemia 2C-3), was achieved 16/30 (53%). For M1 occlusions, first pass effect was 11/18 (61%). Successful reperfusion (modified thrombolysis in cerebral ischemia ≥ 2B) was achieved in 29/30 (97%) cases after a median of 1 pass (interquartile range 1-3). Median groin puncture to reperfusion time was 16 (interquartile range 12-26) minutes. There were no procedural complications or symptomatic intracranial hemorrhage. Average improvement in National Institutes of Health Stroke Scale at discharge was 6.6 ± 7.1. There were three patient deaths (renal failure, respiratory failure, and comfort care). Initial data support the use of Tenzing 7 with FreeClimb 70 catheter for reliable access to rapid, effective, and safe aspiration thrombectomy of large vessel occlusions.

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.

Elevated Hypoperfusion Intensity Ratio (HIR) observed in patients with a large vessel occlusion (LVO) presenting in the evening

BackgroundCircadian variability has been implicated in timing of stroke onset, yet the full impact of underlying biological rhythms on acute stroke perfusion patterns is not known. We aimed to describe the relationship between time of stroke onset and perfusion profiles in patients with large vessel occlusion (LVO). MethodsA retrospective observational study was conducted using prospective registries of four stroke centers across North America and Europe with systematic use of perfusion imaging in clinical care. Included patients had stroke due to ICA, M1 or M2 occlusion and baseline perfusion imaging performed within 24h from last-seen-well (LSW). Stroke onset was divided into eight hour intervals: (1) Night: 23:00-6:59, (2) Day: 7:00-14:59, (3) Evening: 15:00-22:59. Core volume was estimated on CT perfusion (rCBF <30%) or DWI-MRI (ADC <620) and the collateral circulation was estimated with the Hypoperfusion Intensity Ratio (HIR = [Tmax>10s]/[Tmax>6s]). Non-parametric testing was conducted using SPSS to account for the non-normalized dependent variables. ResultsA total of 1506 cases were included (median age 74.9 years, IQR 63.0-84.0). Median NIHSS, core volumes, and HIR were 14.0 (IQR 8.0-20.0), 13.0mL (IQR 0.0-42.0), and 0.4 (IQR 0.2-0.6) respectively. Most strokes occurred during the Day (n = 666, 44.2%), compared to Night (n = 360, 23.9%), and Evening (n = 480, 31.9%). HIR was highest, indicating worse collaterals, in the Evening compared to the other timepoints (p = 0.006). Controlling for age and time to imaging, Evening strokes had significantly higher HIR compared to Day (p = 0.013). ConclusionOur retrospective analysis suggests that HIR is significantly higher in the evening, indicating poorer collateral activation which may lead to larger core volumes in these patients.

Assessing the Relationship between LAMS and CT Perfusion Parameters in Acute Ischemic Stroke Secondary to Large Vessel Occlusion.

The Los Angeles Motor Scale (LAMS) is a rapid pre-hospital scale used to predict stroke severity which has also been shown to accurately predict large vessel occlusions (LVOs). However, to date there is no study exploring whether LAMS correlates with the computed tomography perfusion (CTP) parameters in LVOs. Patients with LVO between September 2019 and October 2021 were retrospectively reviewed and included if the CTP data and admission neurologic exams were available. The LAMS was documented based on emergency personnel exams or scored retrospectively using an admission neurologic exam. The CTP data was processed by RAPID (IschemaView, Menlo Park, CA, USA) with an ischemic core volume (relative cerebral blood flow [rCBF] < 30%), time-to-maximum (Tmax) volume (Tmax > 6 s delay), hypoperfusion index (HI), and cerebral blood volume (CBV) index. Spearman's correlations were performed between the LAMS and CTP parameters. A total of 85 patients were included, of which there were 9 intracranial internal carotid artery (ICA), 53 proximal M1 branch middle cerebral artery M1, and 23 proximal M2 branch occlusions. Overall, 26 patients had LAMS 0-3, and 59 had LAMS 4-5. In total, LAMS positively correlated with CBF < 30% (Correlation Coefficient (CC): 0.32, p < 0.01), Tmax > 6 s (CC:0.23, p < 0.04), HI (CC:0.27, p < 0.01), and negatively correlated with the CBV index (CC:-0.24, p < 0.05). The relationships between LAMS and CBF were < 30% and the HI was more pronounced in M1 occlusions (CC:0.42, p < 0.01; 0.34, p < 0.01 respectively) and proximal M2 occlusions (CC:0.53, p < 0.01; 0.48, p < 0.03 respectively). The LAMS also correlated with a Tmax > 6 s in M1 occlusions (CC:0.42, p < 0.01), and negatively correlated with the CBV index in M2 occlusions (CC:-0.69, p < 0.01). There were no significant correlations between the LAMS and intracranial ICA occlusions. The results of our preliminary study indicate that the LAMS is positively correlated with the estimated ischemic core, perfusion deficit, and HI, and negatively correlated with the CBV index in patients with anterior circulation LVO, with stronger relationships in the M1 and M2 occlusions. This is the first study showing that the LAMS may be correlated with the collateral status and estimated ischemic core in patients with LVO.

White matter disease and recovery following endovascular thrombectomy after acute ischemic stroke (P11-5.006)

<h3>Objective:</h3> To determine the impact of chronic white matter lesions (WML) on functional outcomes in patients with acute stroke who underwent endovascular thrombectomy (EVT). <h3>Background:</h3> The evidence regarding the impact of chronic WML on functional outcomes after EVT is mixed. <h3>Design/Methods:</h3> A prospective stroke center registry (10/2019–06/2021) of consecutive adult patients with acute stroke was queried for patients with ICA or M1 occlusions who had undergone magnetic resonance imaging (MRI). Multivariable logistic regression was used to estimate the relationship between age, Alberta Stroke Program Early Computed Tomography Scale score, National Institutes of Health Stroke Scale, occlusion location, and successful recanalization (thrombolysis in cerebral infarction score of 2b–3 versus 0–2a or no thrombectomy) on good functional outcome (90-day mRS 0–2). Mediation analysis was used to estimate the effect of WML severity on age as a predictor of good functional outcome following successful recanalization. <h3>Results:</h3> Among the 121 included patients, the median age was 67y (IQR 58–77), 49 (40.5%) were female, and 39 (32.2%) had a Fazekas score of 2 or 3. In unadjusted regression, age was associated with WML severity (step 1: OR 1.03, 95% CI 1.02–1.04, p&lt;0.001), and age was associated with an unfavorable 90-day mRS (step 2: proportional OR 0.98, 95% CI 0.95–0.99, p = 0.027). WML severity was also associated with 90-day mRS (step 3: OR 0.74, 95% CI 0.52–1.06, p=0.096). In multivariable regression, the total effect of age on unfavorable shift in 90-day mRS remained significant (OR 0.96, 95% CI 0.94–0.98, p&lt;0.001), with a trend toward a persistent indirect mediator effect of WML (p=0.084). The mediator WML severity explained 23% of the association of age with 90-day mRS. <h3>Conclusions:</h3> In this single center analysis, WML burden partially mediated the effect of age on functional recovery in acute stroke. <b>Disclosure:</b> Mr. Vigilante has nothing to disclose. Ms. Koneru has nothing to disclose. Ms. Penckofer has nothing to disclose. Mr. Sprankle has nothing to disclose. Dr. Patel has nothing to disclose. Dr. Khalife has nothing to disclose. Dr. Oliveira has nothing to disclose. Scott Kamen has nothing to disclose. An immediate family member of Dr. Thon has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Horizon. An immediate family member of Dr. Thon has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Genentech. An immediate family member of Dr. Thon has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Genentech. Dr. Thon has received personal compensation in the range of $500-$4,999 for serving as a Focus group participant with Alexion. Dr. Siegler has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Ceribell. Dr. Siegler has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for AstraZeneca.

Acute Ischemic Stroke Large Vessel Occlusion treated with Mechanical Thrombectomy in the Pediatric Populatio (P8-5.015)

<h3>Objective:</h3> We sought to assess the safety and efficacy of mechanical thrombectomy performed in children at our institution for acute ischemic stroke (AIS) due to large vessel occlusion (LVO). <h3>Background:</h3> AIS due to large vessel occlusion (LVO) is relatively rare in the pediatric population, and evidence supporting thrombectomy in children is limited. The use of thrombectomy in the pediatric population is extrapolated from data in the adult stroke literature. <h3>Design/Methods:</h3> We performed a retrospective chart review of pediatric patients (age &lt; 18 years) with AIS due to LVO who underwent thrombectomy at our comprehensive academic stroke center from January 2019 to June 2022. <h3>Results:</h3> We identified 4 cases of pediatric AIS with LVO treated with thrombectomy. The mean age was 12 years old (range, 9–17), 3 were males. The mean National Institutes of Health Stroke Scale was 16 (range, 10 to 28). One patient received partial thrombolysis (aborted with 20% of dose received). Prior to thrombectomy, 1 patient had CT brain perfusion which showed MCA mismatch favorable for thrombectomy, whereas the remaining 3 patients had MRI brain showing acute infarct in the territory of LVO. LVO sites included M1 occlusion (2), carotid T occlusion (1), and M2 occlusion (1). All 4 patients had successful revascularization including 3 patients with thrombolysis in cerebral infarction (TICI) 3 and 1 patient with TICI 2b. There were no symptomatic hemorrhages. The mean time from last known normal to groin puncture was 5.7 hours (range, 2.9 to 9.2). The clinical outcomes included 2 patients with modified rankin scores (mRS) 1 and 2 patients with mRS 3. <h3>Conclusions:</h3> In our case series of pediatric AIS cases with LVO, thrombectomy was feasible and associated with successful revascularization. There were no safety concerns. The majority of cases were diagnosed by MRI brain, highlighting the difficulty in diagnosis of LVO in the pediatric population. <b>Disclosure:</b> Mrs. Glenn has nothing to disclose. Dr. Lee has nothing to disclose. Shahid Nimjee has nothing to disclose. The institution of Dr. Lo has received research support from NIH. Dr. Lo has received publishing royalties from a publication relating to health care. Mrs. Forrest has nothing to disclose. Randheer Yadav has stock in Quest Recovery Center LLC. Patrick Youssef has nothing to disclose.

Real World Experience with Viz.ai Automated Large Vessel Occlusion in CT Angiogram (P8-5.010)

<h3>Objective:</h3> To determine the accuracy of Viz.AI LVO at our large academic comprehensive stroke center. <h3>Background:</h3> Viz.AI LVO is an artificial-intelligence platform which analyzes brain computed tomography angiography (CTA) images in patients with suspected acute ischemic stroke (AIS) and sends an automated alert for suspected large vessel occlusions (LVO). Viz.AI reports high sensitivity and specificity (96.3% and 93.8%); we report our experience with Viz.AI LVO detection. <h3>Design/Methods:</h3> We performed a retrospective review of suspected stroke patients who had CTA ordered as a stroke code from September 2020–May 2021. Data was collected on sex, age, Viz.AI LVO alert, and CTA radiologist review (considered gold standard). True negative was defined as Viz negative, Radiology negative, False positive as Viz positive, Radiology negative, false negative as Viz negative, Radiology positive, and true positive as Viz positive, Radiology positive. LVO was defined as occlusion of the intracranial carotid (ICAT) or MCA (M1 or M2). Data collected included performance of Viz.AI LVO alert, sensitivity, specificity, positive predictive value, and negative predictive value. <h3>Results:</h3> Among 980 consecutive suspected AIS patients with CTA analyzed by Viz.AI, the mean age was 64.2 years (range 19–99) and 531 (54.3%) were female. Viz LVO autodetection alerted for 161 patients (16.4%). Radiologist review reported 85 patients (8.7%) with LVO as follows: 33 (38.8%) M2, 36 (42.4%) M1, and 16 (18.8%) ICAT. The following were adjudicated: 805 true negatives, 90 false positives, 14 false negatives, and 71 true positives. Sensitivity was 83.5%, specificity 89.9%, PPV 44.1%, and NPV 98.3%. All 14 false negatives were M2 occlusions. The median time to alert (TTA) was 11 min (range 6–656). <h3>Conclusions:</h3> In our series of AIS patients evaluated with CTA at an academic CSC, Viz.AI automated LVO detection performed well with a sensitivity of 83.5%, specificity of 89.9%, and a median TTA of 11 minutes. <b>Disclosure:</b> Dr. Mannix has nothing to disclose. Ms. Penhos has nothing to disclose. Shahid Nimjee has nothing to disclose. Mohammad Taimur Shujaat has nothing to disclose. Ms. Hammond-Heaton has nothing to disclose. Dr. Vitellas has nothing to disclose. Dr. Lee has nothing to disclose.