Differentiating Carotid Terminus Occlusions into Two Distinct Populations Based on Willisian Collateral Status

Clinical and imaging predictors for hemorrhagic transformation of acute ischemic stroke after endovascular thrombectomy

BACKGROUND AND PURPOSE

Hemorrhagic transformation (HT) is a common complication of endovascular thrombectomy (EVT) in patients with acute ischemic stroke (AIS). Our study aims to investigate the clinical and imaging predictors of HT and symptomatic intracranial hemorrhage (sICH) in patients who underwent EVT.

METHODS

A retrospective analysis of 118 patients undergoing EVT for acute anterior circulation stroke was performed. Potential clinical and imaging predictors of all patients were collected and multivariate logistic regression was performed. The risk prediction system was constructed according to the multivariate logistic regression results.

RESULTS

The incidence of HT and sICH after EVT were 46.6% and 15.3%, respectively. The multivariate logistic regression results showed that Alberta Stroke Program Early CT Score (ASPECTS) (p = .001, odds ratio [OR] = 0.367, 95% [confidence interval] CI, 0.201-0.670), collateral status (p<.001, OR = 0.117, 95% CI, 0.042-0.325), relative cerebral blood flow (CBF) ratio (p = .025, OR = 0.943, 95% CI, 0.895-0.993), and blood glucose on admission (p = .012, OR = 1.258, 95% CI, 1.053-1.504) were associated with HT. While for sICH, collateral circulation (p = .007, OR = 0.148, 95% CI, 0.037-0.589), ASPECTS (p = .033, OR = 0.510, 95% CI, 0.274-0.946), and blood glucose (p = .005, OR = 1.304, 95% CI, 1.082-1.573) were independent factors. The predictive model for HT after EVT was established, and the sensitivity and specificity of it were 90.9% and 79.4%, respectively, with the area under the curve of 90.0% (84.5%-95.4%).

CONCLUSION

Collateral status, ASPECTS, relative CBF ratio, and blood glucose on admission were predictors for HT in AIS patients, while collateral status, ASPECTS, and blood glucose on admission were also predictors for sICH. In addition, the established predictive model showed good diagnostic value for prediction of HT after EVT.

Pre-navigation balloon technique: Distal emboli protection during stent retriever thrombectomy

OBJECTIVE

During stent retriever thrombectomy, a balloon guide catheter reduces distal emboli and consequently improves clinical outcomes. Because balloons are usually used before stent retrieval, these can affect the thrombus including the distal emboli while performing microcatheter navigation. This study aimed to evaluate the usefulness and safety of the pre-navigation balloon technique during microcatheter and microwire navigation.

METHODS

Patients who underwent stent retriever thrombectomy secondary to an anterior circulation large-artery occlusion were retrospectively evaluated. The pre-navigation balloon technique was used, and the number of retrievals, procedure time, final recanalization, presence of distal emboli, first-pass effect (FPE), symptomatic intracranial hemorrhage including procedure-related complications, and clinical outcomes at 3 months were evaluated.

RESULTS

In total 123 patients were analyzed, and occurrence of distal emboli was lesser in the pre-navigation balloon than in the non-preballoon group (4.4% vs. 11.5%, p = 0.02). No statistical difference was found in successful recanalization, mortality, and procedure-related complications. Moreover, the pre-navigation balloon group had a higher FPE than the non-balloon group (37.8% vs. 20.5%, p = 0.004). Although no statistical difference was found in the pre-navigation balloon group, a trend toward a higher rate of good clinical outcomes was observed (mRS 0-2 at 3 months, 55.6% vs. 48.7%, p = 0.09). For ICA occlusion(n = 35), significant effects were seen in decreasing distal embolism (0(0%) vs 3(16%), p = 0.01), increasing FPE (8(50%) vs 6(32%), p = 0.003), and improving clinical outcomes (mRS 0-2 at 3 months, 9(56%) vs 7(37%), p = 0.03) in the pre-navigation balloon group. In the multivariate analysis, lesser distal embolism (0.91 [0.80-1.00], p = 0.02), higher successful recanalization (3.52 [1.11-7.03], p = 0.016), and higher FPE (3.17 [1.83-7.37], p = 0.001) secondary to the procedure was a predictor of favorable clinical outcomes.

CONCLUSIONS

The pre-navigation balloon technique significantly reduced occurrence of distal embolism and increased the FPE.

Circle of Willis Configuration and Thrombus Localization Impact on Ischemic Stroke Patient Outcomes: A Systematic Review

Background and Objectives: The published literature highlights the fact that the integrity of the Circle of Willis has a direct impact on stroke outcome, especially in cases of distal internal carotid T occlusion. The aim of this study was to review the available data on the Circle of Willis configuration and thrombus location impact on patient outcome in cases of ischemic stroke. Materials and Methods: A systematic search according to PRISMA guidelines was performed in PubMed, Cochrane, and EMBASE databases to identify studies investigating the influence of Circle of Willis variants on ischemic stroke outcomes published up to March 2023. The manuscripts were reviewed by three researchers separately and scored on the quality of the research using the MINORS criteria. Results: After screening 157 manuscripts, 11 studies (n = 4643) were included. Circle of Willis integrity plays a vital role in stroke outcome, especially when T-form occlusions are present. Despite this, in the event of M1 occlusion Circle of Willis configuration does not play an important role. In cases of distal internal carotid artery occlusion, the presence of a fully developed contralateral A1 segment and anterior communicating artery is essential for a favorable stroke outcome. Conclusions: The preserved integrity of the Circle of Willis has great significance for collateral flow in the event of ischemic stroke and helps patients to achieve more favorable outcomes, as it determines the affected brain territory. The clinical outcome of the ischemic stroke appears to be significantly better if only one artery territory is affected, compared to two or more.

Higher number of stent-retriever thrombectomy passes significantly increases risk of mass effect, poor functional outcome, and mortality

INTRODUCTION

Endovascular treatment (EVT) is a widely proven method to treat patients diagnosed with intracranial large vessel occlusion (LVO). Through this method of treatment, it has been hypothesized that a lower number of thrombectomy passes is an indicator of higher rates of modified Thrombolysis in Cerebral Infarction 2B-3 (mTICI) reperfusion and favorable outcomes at 90-days defined as modified Rankin Scale 0-2 (mRS).

METHODS

Through the utilization of a prospectively collected endovascular database between 2012-2020, variables such as demographics, co-morbid conditions, intracerebral hemorrhage, mass effect, mortality rate, and good/poor outcomes regarding mTICI score and mRS assessment at 90-days were examined. The outcomes between patients receiving EVT who were treated with < 3 thrombectomy passes or ≥3 passes were compared.

RESULTS

Out of 454 patients treated with mechanical thrombectomy of qualifying intracranial internal carotid artery (ICA) or middle cerebral artery occlusion, site of occlusion (ICA, ICA-T M1, and M2/M3), a total of 372 (81.9%) were treated with < 3 passes (average age 70.34 ± 13.75 years, 46.0% women), and 82 (18.1%) were treated with ≥3 passes (average age 70.30 ± 13.72 years, 48.8% women). Significantly higher rates of mass effect (p = 0.043), mRS score 3-6 (p = 0.029), mortality (p = 0.025), and poor reperfusion (p < 0.0001) were noted in patients treated with ≥3 passes.

CONCLUSION

A higher number of thrombectomy passes, characterized as ≥3 in this study, was associated with significantly worsened patient outcome regarding mRS and mortality. Further research is required to determine whether the number of thrombectomy passes is an accurate predictor of treatment outcome.

The relationship between occlusion patterns and outcomes after thrombectomy in patients with acute internal carotid artery occlusion

BACKGROUND AND PURPOSES

Ischemic stroke caused by acute internal carotid artery occlusions (AICO) is usually associated with high disability and mortality. We aimed to investigate whether occlusion patterns significantly influence clinical outcome in patients receiving endovascular thrombectomy (EVT).

PATIENTS AND METHODS

We performed a retrospective analysis of databases from two comprehensive stroke centers and consecutively investigated patients who had underwent EVT. AICO was defined as acute internal carotid artery occlusions (cervical segment to terminal segment). The clinical characteristics, intervention parameters, and prognosis data were collected. Leptomeningeal collaterals (LMC) were assessed with the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology scale (ASITN/SIRs), graded on a 5-point scale. The occlusion patterns based on Willisian collaterals were categorized into I-type, L-type, and T-type by contralateral carotid artery injections at digital subtraction angiography. Multivariate regression models were applied to evaluate the relationship between occlusion patterns and the prognosis of patients at 90 days after stroke.

RESULTS

A total of 213 patients were included in the study. Of those,142 (66.7%) achieved successful reperfusion and 64 (30.0%) achieved favorable outcomes at 90 days. Overall, 26 (12.2%), 117 (54.9%), and 70 (32.9%) cases respectively suffered from I-type, L-type, and T-type occlusion. In addition, patients with I-type occlusions had a higher percentage of complete LMC compared with L-type or T-type occlusions (88.5% versus 30.8% versus 27.1%, P< 0.0167). In multivariable logistic regression, we found T-type occlusion was no longer an independent predictor of poor functional outcomes in AICO after adjusting LMC (T versus I, OR, 2.555, 95%CI: 0.717-9.103, P = 0.148; L versus I, OR, 0.815, 95%CI: 0.258-2.574, P = 0.727).

CONCLUSIONS

For ACIO, occlusion patterns are still a topic that needs attention. Furthermore, compensatory LMC may affect the association between occlusion patterns and functional prognosis in AICO. Occlusion patterns and LMC status distinguish the nature and impact of AICO on expected EVT and subsequent clinical outcomes.

Ischemic Lesion Growth in Patients with a Persistent Target Mismatch After Large Vessel Occlusion

BACKGROUND

Failure to reperfuse a cerebral occlusion resulting in a persistent penumbral pattern has not been fully described.

METHODS

We retrospectively reviewed patients with anterior large vessel occlusion who did not receive reperfusion, and underwent repeated perfusion imaging, with baseline imaging < 6 h after onset and follow-up scans from 16-168 h. A persistent target mismatch (PTM) was defined as core volume of < 100 mL, mismatch ratio > 1.2, and mismatch volume > 10 mL on follow-up imaging. Patients were divided into PTM or non-PTM groups. Ischemic core and penumbral volumes were compared between baseline and follow-up imaging between the two groups, and collateral flow status assessed using CT perfusion collateral index.

RESULTS

A total of 25 patients (14 PTM and 11 non-PTM) were enrolled in the study. Median core volumes increased slightly in the PTM group, from 22 to 36 ml. There was a much greater increase in the non-PTM group, from 57 to 190 ml. Penumbral volumes were stable in the PTM group from a median of 79 ml at baseline to 88 ml at follow-up, whereas penumbra was reduced in the non-PTM group, from 120 to 0 ml. Collateral flow status was also better in the PTM group and the median collateral index was 33% compared with 44% in the non-PTM group (p = 0.043).

CONCLUSION

Multiple patients were identified with limited core growth and large penumbra (persistent target mismatch) > 16 h after stroke onset, likely due to more favorable collateral flow.

Triptonide Ameliorates Middle Cerebral Artery Occlusion-induced Cerebral Ischemic Damage in Rats via Regulation of In flammatory Response

Background

Cerebral ischemic stroke is the second major cause of mortality worldwide that results in persisting disability and mental agony. Ischemic stroke is induced by the diminished blood circulation to the brain, which can be due to obstruction by arteriosclerosis, fibromuscular dysplasia, or thrombosis. Triptonide is a diterpene triepoxide, purified out of extracts of Tripterygium wilfordii Hook F, and is an emerging target against, for example, cancers and inflammatory insults.

Materials and Methods

Taking this into consideration, this study was designed to analyze the effect of triptonide on ischemic/reperfusion (I/R) cerebral infarction stroke rats.

Results

Our study showed that triptonide decreased the infarct volume and brain edema produced by I/R. Moreover, triptonide protected the rats from any neurological deficits, which were analyzed using a five-point scoring system, augmented antioxidant enzymes like superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione content, and lowered the activity of acetylcholinesterase. Triptonide also decreased the levels of pro-inflammatory cytokines such as interleukin-1 β (IL-1 β), TNF- α, and IL-6, while it augmented anti-inflammatory cytokines IL-10 and vascular endothelial growth factor. In this study, cerebral infarction stroke rats showed an increase in malondialdehyde levels. Triptonide preserved the normal brain architecture from various neurotoxic effects.

Conclusion

Thus, triptonide can be targeted for drug discovery in the future to protect against cerebral infarction stroke.

Neuroimaging of Acute Ischemic Stroke: Multimodal Imaging Approach for Acute Endovascular Therapy

Advances in acute ischemic stroke (AIS) treatment have been contingent on innovations in neuroimaging. Neuroimaging plays a pivotal role in the diagnosis and prognosis of ischemic stroke and large vessel occlusion, enabling triage decisions in the emergent care of the stroke patient. Current imaging protocols for acute stroke are dependent on the available resources and clinicians' preferences and experiences. In addition, differential application of neuroimaging in medical decision-making, and the rapidly growing evidence to support varying paradigms have outpaced guideline-based recommendations for selecting patients to receive intravenous or endovascular treatment. In this review, we aimed to discuss the various imaging modalities and approaches used in the diagnosis and treatment of AIS.

Posterior Limb of Internal Capsule Infarct Predicts Functional Outcome in Acute Terminal Internal Carotid Artery Occlusion After Thrombectomy

PURPOSES

This study investigated the impact of posterior limb of internal capsule (PLIC) infarct on outcomes of acute internal carotid artery (ICA) occlusion after endovascular thrombectomy (EVT) and the diagnostic accuracy of pretreatment noncontrast computerized tomography (NCCT) and computerized tomography angiography (CTA) findings.

METHODS

Patients who underwent EVT for acute ICA occlusion between September 2014 and August 2020 were included in the study. The patients were dichotomized as PLIC infarct or spared. The risk factors for PLIC infarct were investigated, and the association between infarct patterns and clinical outcomes were assessed using logistic regression analysis. Pretreatment NCCT and CTA findings, including PLIC hypodensity, choroid plexus enhancement (CPE), and posterior cerebral artery (PCA) flow status, were calculated for diagnosis of PLIC infarct.

RESULTS

Among 72 patients, the mean age was 70.9 years, and the mean stroke scale was 19.4. PLIC infarct was identified in 15 patients (20.8%). PLIC infarct was associated with worse 90-day functional outcome (P = 0.01, shift test). Lack of CPE is the only independent predictor of PLIC infarct (odds ratio: 127.48, P = 0.001). Lack of CPE and impaired PCA flow produce greater diagnostic accuracy for PLIC infarct than does NCCT hypodensity (area under the receiver operating characteristics curve: 0.85 and 0.76, P = 0.0005 and 0.02, respectively).

CONCLUSIONS

In acute ICA occlusion, PLIC infarct is an independent risk factor for worse clinical outcome at 90 days. The lack of CPE was associated with PLIC infarct, and pretreatment CTA can be useful for early diagnosis.

Large Vessel Occlusion Sites Affect Agreement Between Outputs of Three Computed Tomography Perfusion Software Packages

OBJECTIVES

Computed tomography perfusion (CTP) data are important for hyperacute stroke decision making. Available comparisons between outputs of different CTP software packages show variable outcomes. Evaluation for factors associated with agreement between the volume estimates is limited. We assessed for differences in core and penumbra volume estimates of three CTP software packages - AutoMIStar, RAPID, and Vitrea - and analyzed factors associated with agreement between the volume estimates.

MATERIALS AND METHODS

Differences between software estimates of penumbra and core volumes were calculated for each patient with suspected acute ischemic stroke who underwent CTP. Exploratory hierarchical clustering and principal component analysis were performed to identify factors of decreased volume estimate agreement. Two-sample t-tests were performed, stratified by large vessel occlusion (LVO) location.

RESULTS

579 CTP studies were performed; 267 were normal, 139 artifacts, with 172 included in the final analysis. 79/172 had LVO of internal carotid artery (ICA, n = 20), M1 (n = 38) and proximal M2 (n = 21). LVO was the only factor associated with decreased software package agreement, and proximal LVO location was associated with general trend of increasing mean differences and standard deviations between software packages (range of mean differences [SD]: non-LVO, -17-6 [4-33] ml; M2, -40-13 [5-39] ml; M1, -43-26 [16-58] ml; ICA, -76-39 [22-97] ml).

CONCLUSIONS

Core and penumbra volume estimates can be affected by LVO location significantly between CTP software packages.

Functional Aplasia of the Contralateral A1 Segment Influences Clinical Outcome in Patients with Occlusion of the Distal Internal Carotid Artery

Background: The importance of an A1 aplasia remains unclear in stroke patients. In this work, we analyze the impact of an A1 aplasia contralateral to an acute occlusion of the distal internal carotid artery (ICA) on clinical outcomes. Methods: We conducted a retrospective study of consecutive stroke patients treated with mechanical thrombectomy at 12 tertiary care centers between January 2015 and February 2021 due to an occlusion of the distal ICA. Functional A1 aplasia was defined as the absence of A1 or hypoplastic A1 (>50% reduction to the contralateral site). Functional independence was measured by the modified Rankin Scale (mRS ≤ 2). Results: In total, 81 out of 1068 (8%) patients had functional A1 aplasia contralateral to distal ICA occlusion. Patients with functional contralateral A1 aplasia were more severely affected on admission (median NIHSS 18, IQR 15−23 vs. 17, IQR 13−21; aOR: 0.672, 95% CI: 0.448−1.007, p = 0.054) and post-interventional ischemic damage was larger (median ASPECTS 5, IQR 1−7, vs. 6, IQR 3−8; aOR: 1.817, 95% CI: 1.184−2.789, p = 0.006). Infarction occurred more often within the ipsilateral ACA territory (20/76, 26% vs. 110/961, 11%; aOR: 2.482, 95% CI: 1.389−4.437, p = 0.002) and both ACA territories (8/76, 11% vs. 5/961, 1%; aOR: 17.968, 95% CI: 4.979−64.847, p ≤ 0.001). Functional contralateral A1 aplasia was associated with a lower rate of functional independence at discharge (6/81, 8% vs. 194/965, 20%; aOR: 2.579, 95% CI: 1.086−6.122, p = 0.032) and after 90 days (5/55, 9% vs. 170/723, 24%; aOR: 2.664, 95% CI: 1.031−6.883, p = 0.043). Conclusions: A functional A1 aplasia contralateral to a distal ICA occlusion is associated with a poorer clinical outcome.

Leptomeningeal anastomoses: Mechanisms of pial collateral remodeling in ischemic stroke

Arterial collateralization, as determined by leptomeningeal anastomoses or pial collateral vessels, is a well‐established vital player in cerebral blood flow restoration and neurological recovery from ischemic stroke. A secondary network of cerebral collateral circulation apart from the Circle of Willis, exist as remnants of arteriole development that connect the distal arteries in the pia mater. Recent interest lies in understanding the cellular and molecular adaptations that control the growth and remodeling, or arteriogenesis, of these pre‐existing collateral vessels. New findings from both animal models and human studies of ischemic stroke suggest a multi‐factorial and complex, temporospatial interplay of endothelium, immune and vessel‐associated cell interactions may work in concert to facilitate or thwart arteriogenesis. These valuable reports may provide critical insight into potential predictors of the pial collateral response in patients with large vessel occlusion and may aid in therapeutics to enhance collateral function and improve recovery from stroke.

This article is categorized under:

Neurological Diseases > Molecular and Cellular Physiology

Factors Contributing to an Efficacious Endovascular Treatment for Acute Ischemic Stroke in Asian Population

Although randomized control trials about endovascular treatment (EVT) of emergent large vessel occlusion (LVO) have demonstrated the success of mechanical thrombectomy as the choice of treatment, a wide range of caveats remain unaddressed. Asian patients were rarely included in the trials, thereby raising the question of whether the treatment could be generalized. In addition, there remains a concern on the feasibility of the method with respect to its application against intracranial atherosclerosis (ICAS)-related LVO, frequently observed in the Asian population. It is important to include evidence on ICAS LVO from Asian countries in the future for a comprehensive understanding of LVO etiology. Besides the issues with EVT, prognostic concerns in diabetes patients, acute kidney injury following EVT, neuroprotective management against reperfusion injury, and other peri-EVT issues should be considered in clinical practice. In the current article, we present an in-depth review of the literature that revises information pertaining to such concerns.

Mechanical Thrombectomy for Acute Intracranial Carotid Occlusion with Patent Intracranial Arteries : The Italian Registry of Endovascular Treatment in Acute Stroke

PURPOSE

Intracranial carotid artery occlusion represents an underinvestigated cause of acute ischemic stroke as well as an indication for mechanical thrombectomy. We investigated baseline and procedural characteristics, outcomes and predictors of outcome in patients with acute ischemic stroke secondary to intracranial carotid artery occlusion.

METHODS

A retrospective analysis of the Italian Registry of Endovascular Treatment in Acute Stroke was performed. Patients with intracranial carotid artery occlusion (infraclinoid and supraclinoid) with or without cervical artery occlusion but with patent intracranial arteries were included. The 3‑month functional independence, mortality, successful reperfusion and symptomatic intracranial hemorrhage were evaluated.

RESULTS

Intracranial carotid artery occlusion with patent intracranial arteries was diagnosed in 387 out of 4940 (7.8%) patients. The median age was 74 years and median baseline National Institute of Health Stroke Scale (NIHSS) was 18. Functional independence was achieved in 130 (34%) patients, successful reperfusion in 289 (75%) and symptomatic intracranial hemorrhage in 33 (9%), whereas mortality occurred in 111 (29%) patients. In univariate analysis functional independence was associated with lower age, lower NIHSS at presentation, higher rate of successful reperfusion and lower rate of symptomatic intracranial hemorrhage. Multivariable regression analysis found age (odds ratio, OR:1.03; P = 0.006), NIHSS at presentation (OR: 1.07; P < 0.001), diabetes (OR: 2.60; P = 0.002), successful reperfusion (OR:0.20; P < 0.001) and symptomatic intracranial hemorrhage (OR: 4.17; P < 0.001) as the best independent predictors of outcome.

CONCLUSION

Our study showed a not negligible rate of intracranial carotid artery occlusion with patent intracranial arteries, presenting mostly as severe stroke, with an acceptable rate of 3‑month functional independence. Age, NIHSS at presentation and successful reperfusion were the best independent predictors of outcome.

Predictors and prognoses of Willisian collateral failure during mechanical thrombectomy

During mechanical thrombectomy in the anterior cerebral circulation, thrombus embolization resulting in Willisian collateral failure may lead to critical stroke outcomes due to a shutdown of leptomeningeal collaterals. We hypothesized that the outcomes of dynamic Willisian collateral failure (DWF), induced during mechanical thrombectomy, would be associated with grave outcomes. We evaluated this hypothesis in consecutive patients, between January 2011 and May 2016, who underwent mechanical thrombectomy for anterior circulation occlusions, with an onset-to-puncture of 24 h. Patients with initial Willisian collateral failure (IWF) were identified first, with remaining patients classified into the DWF and Willisian collateral sparing (WCS) groups. Comparative and multivariable analyses were performed to predict grave outcomes (3-month modified Rankin Scale score of 5–6). Among 567 patients, 37 were in the IWF group, 38 in the DWF group, and 492 in the WCS group. Compared to the WCS and DWF groups, the IWF group had a higher baseline National Institute of Health Stroke Scale score and lower Alberta Stroke Program Early CT Score. The prevalence of grave outcomes was similarly high in the IWF (48.6%) and DWF (47.4%) groups, but lower in the WCS group (22.0%; p < 0.001). IWF and DWF were independent risk factors for a grave outcome.

Optic nerve sheath diameter change in prediction of malignant cerebral edema in ischemic stroke: an observational study

Background

In acute large anterior circulation infarct patients with large core volume, we evaluated the role of optic nerve sheath diameter (ONSD) change rates in prediction of malignant progression.

Methods

We performed a retrospective observational study including patients with anterior circulation acute ischemic stroke with large ischemic cores from January 2010 to October 2017. Primary outcome was defined as undergoing decompressive surgery or death due to severe cerebral edema, and termed malignant progression. Patients were divided into malignant progressors and nonprogressors. Malignant progression was divided into early progression that occurred before D1 CT, and late progression that occurred afterwards. Retrospective analysis of changes in mean ONSD/eyeball transverse diameter (ETD) ratio, and midline shifting (MLS) were evaluated on serial computed tomography (CT). Through analysis of CT at baseline, postprocedure, and at D1, the predictive ability of time based change in ONSD/ETD ratio in predicting malignant progression was evaluated.

Results

A total of 58 patients were included. Nineteen (32.8%) were classified as malignant; 12 early, and 7 late progressions. In analysis of CT_{postprocedure}, A 1 mm/hr. rate of change in MLS during the CT_baseline-CT_{postprocedure} time phase lead to a 6.7 fold increased odds of early malignant progression (p < 0.05). For ONSD/ETD, 1%/hr. change lead to a 1.6 fold increased odds, but this association was trending (p = 0.249). In the CT_D1, 1%/day change of ONSD/ETD in the CT_baseline-CT_D1 time phase lead to a 1.4 fold increased odds of late malignant progression (p = 0.021) while 1 mm/day rate of change in MLS lead to a 1.5 fold increased odds (p = 0.014).

Conclusions

The rate of ONSD/ETD changes compared to baseline at D1 CT can be a predictor of late malignant progression along with MLS. ONSD/ETD change rates evaluated at postprocedure did not predict early malignant progression.

Pseudo-Occlusion of the Internal Carotid Artery in Acute Ischemic Stroke: Clinical Outcome after Mechanical Thrombectomy

Pseudo-occlusion (PO) of the cervical internal carotid artery (cICA) can be caused by distal ICA occlusion. We explored the clinical impact of PO after mechanical thrombectomy (MT). Patients who underwent MT to treat distal ICA occlusions between July 2012 and March 2018 were reviewed. A cICA-PO was defined as when single phase computed tomography angiography (CTA) revealed a gradual decline in contrast above the level of the carotid bulb. We investigated the relationship between a cICA-PO and outcome; we also explored the association between successful recanalization and outcome. Among 71 patients, 40 (56.3%) exhibited cICA-PO and more likely to experience poor outcomes (80.0% vs. 25.8%, P < 0.001), hemorrhagic transformation (32.5% vs. 9.6%, P = 0.01), and a lower rate of successful recanalization (65.0% vs. 90.3%, P = 0.014) than the non-PO group. In binary logistic regression, a cICA-PO was independently associated with a poor outcome (odds ratio, 4.278; 95% CI, 1.080-33.006; P = 0.045). In the cICA-PO group, all patients who failed recanalization (n = 15) experienced poor outcomes, as did 69.2% of patients in whom recanalization was successful (P = 0.018). cICA-POs are common and have worse outcomes than non-PO patients. Patients with cICA-POs are more likely to exhibit poor outcomes after MT, particularly when recanalization fails.

Collateral grade of the Willis' circle predicts outcomes of acute intracranial internal carotid artery occlusion before thrombectomy

BACKGROUND AND PURPOSE

Endovascular mechanical thrombectomy (EVMT) shows significant promise in improving acute ischemic stroke (AIS) with proximal artery occlusion, but outcomes have been variable. We explored the patients treated by thrombectomy to investigate the association between a favorable clinical outcome of EVMT in intracranial internal carotid artery occlusion (iICAO) and a set of predictors.

METHODS

A total of 38 iICAO patients treated by EVMTs were analyzed. Primary collateral grades (PCG) at baseline based on the integrity of Willis' circle were categorized into three degrees. The favorable outcomes, measured by modified Rankin scale (mRS), were defined as ≤2 at 90 days. The reperfusion was one of the most important confounders, defined as modified thrombolysis in cerebral infarction (mTICI) ≥ 2b. The other risk factors included demographic characteristics, vascular risk factors, stroke severity, procedural EVMT, and PCG at baseline was adjusted to reveal the association with favorable outcomes.

RESULTS

Of 38 iICAO patients, 65.8% (25 in 38) achieved reperfusion. However, only 31.6% (12/38) achieved favorable outcomes at 90 days. With a PCG3, 61.5% of them achieved favorable outcomes, while only 37.5% of those with PCG2 and PCG1 achieved favorable outcomes (p = .003). In multivariable logistic regression, PCG was revealed as a predictor for favorable outcomes (OR 5.278, p = .019) after adjusting the reperfusion and other factors.

CONCLUSIONS

The PCG based on the integrity of Willis' circle might be an underlying predictor of the prognosis of AIS in patients with iICAO after EVMT. The function of intact anterior communicating artery (AcoA) and ipsilateral posterior communicating artery (PcoA) in favoring prognosis of the iICAO patients might need to be validation in future study.

Genetic and Environmental Contributions to Variation in the Posterior Communicating Collaterals of the Circle of Willis

Variation in blood flow mediated by the posterior communicating collateral arteries (PComs) contributes to variation in the severity of tissue injury in obstructive disease. Evidence in animals and humans indicates that differences in the extent of PComs, i.e., their anatomic lumen diameter and whether they are present bilaterally, unilaterally, or absent, are a major factor. These differences arise during development since they are present at birth. However, the causal mechanisms are unknown. We used angiography after maximal dilation to examine involvement of genetic, environmental, and stochastic factors. The extent of PComs varied widely among seven genetically diverse strains of mice. Like pial collaterals in the microcirculation, aging and hypertension reduced PCom diameter, while in contrast, obesity, hyperlipidemia, metabolic syndrome, and diabetes mellitus had no effect. Naturally occurring intrauterine growth restriction had no effect on extent of PCom or pial collaterals in the adult. The number and diameter of PComs evidenced much larger apparent stochastic-dependent variation than pial collaterals. In addition, both PComs underwent flow-mediated outward remodeling after unilateral permanent MCA occlusion that varied with genetic background and was greater on the ipsilesional side. These findings indicate that variation in the number and diameter of PCom collateral arteries arises from stochastic factors and naturally occurring genetic variants that differ from those that cause variation in pial collateral arterioles. Environmental factors also contribute: aging and hypertension reduce PCom diameter. Our results suggest possible sources of variation of PComs in humans and provide information relevant when studying mouse models of occlusive cerebrovascular disease.

Efficacy and Safety of Endovascular Treatment in Patients with Internal Carotid Artery Occlusion and Collateral Middle Cerebral Artery Flow

Objective

In patients with internal carotid artery (ICA) occlusion, collateral middle cerebral artery (MCA) flow has a protective role against ischemia. However, some of these patients may experience initial major neurological deficits and major worsening on following days. Thus, we investigated the safety and efficacy of endovascular treatment (EVT) for ICA occlusion with collateral MCA flow by comparing clinical outcomes of medical treatment versus EVT.

Methods

The inclusion criteria were as follows : 1) acute ischemic stroke with ICA occlusion and presence of collateral MCA flow on transfemoral cerebral angiography (TFCA) and 2) hospital arrival within 12 hours from symptom onset. The treatment strategy was made by the attending physician based on the patient’s clinical status and results of TFCA.

Results

Eighty-one patients were included (30 medical treatment, 51 EVT). The EVT group revealed a high incidence of intracranial ICA occlusion, longer ipsilesional MCA contrast filling time, and a similar rate of favorable clinical outcome despite a higher mean baseline the National Institutes of Health Stroke Scale (NIHSS) score. By binary logistic regression analysis, intravenous recombinant tissue plasminogen activator and EVT were independent predictors of favorable clinical outcome. In subgroup analysis based on stroke etiology, the non-atherosclerotic group showed a higher baseline NIHSS score, higher incidence of EVT, and a higher rate of distal embolization during EVT in comparison with the atherosclerotic group.

Conclusion

In patients with ICA occlusion and collateral MCA flow, decisions regarding treatment strategy based on TFCA can help achieve favorable clinical outcomes. EVT strategy with respect to etiology of ICA occlusion might help achieve better angiographic outcomes.

Acute Occlusion of the Distal Internal Carotid Artery : Single Center Experience in 46 Consecutive Cases, review of the literature and proposal of a classification

PURPOSE

The acute distal intracranial occlusion of the internal carotid artery (ICA) is a very complex heterogeneous pathology, characterized by various patterns. Aim of this work is to identify the different types and propose a classification.

METHODS

Among the patients admitted for stroke in the anterior circulation from august 2014 to October 2017, 46 (25%) presented with intracranial distal carotid artery occlusion. The mean age of the patients was 71 (SD 13.7), 65,2% female. The protocol included general and specific neurological examinations, CT, CT-Angiography with multiphase CTA, followed by Angiography. The occlusion was treated by aspiration device alone or associated with stent-retriever. NIHSS at the admission, at discharge and modified ranking Scale (mRS) at four months were examined.

RESULTS

The occlusions presented with various patterns. Depending on its site (located at the distal ICA bifurcation or more proximal at the level of the ophthalmic segment of ICA, with or without extent to ICA bifurcation) taking also into account the various involvement of the cerebral vessels and anatomic variations of Circle of Willis, three groups of occlusion types could be identified (T1, T2 and T3). The collateral circulation, and the possibilities of the endovascular revascularization important for the final outcome, were clearly connected with the type of occlusion. NIHSS at admission was 19.1 (Range from 8 to 30, SD 4.4). Good outcome defined as mRS 0-2 at for months was obtained in 17 patients (37%).

CONCLUSIONS

The proposed classification reproduces more precisely the complexity and heterogeneity of this pathology, being useful in the diagnosis and treatment of these patients.

Prognosis of Acute Intracranial Atherosclerosis-Related Occlusion after Endovascular Treatment

Background and Purpose

Little is known about prognosis after endovascular therapy (EVT) for acute large artery occlusion (LAO) caused by underlying intracranial atherosclerotic stenosis (ICAS). Therefore, we investigated the prognosis following EVT according to the underlying etiology of LAO.

Methods

Patients from the Acute Stroke due to Intracranial Atherosclerotic occlusion and Neurointervention-Korean Retrospective (ASIAN KR) registry (n=720) were included if their occlusion was in the intracranial anterior circulation and their onset-to-puncture time was <24 hours. Occlusion was classified according to etiology as follows: no significant stenosis after recanalization (Embolic group), and fixed significant focal stenosis in the occlusion site with flow impairment or re-occlusion observed during EVT (ICAS group). Patients were excluded when significant extracranial carotid lesions existed, and when the intracranial occlusion was intractable to EVT so that the etiology was undetermined. The effect of angiographic etiologic classification on outcomes was evaluated using multivariable analysis that was adjusted for potential confounders.

Results

Among eligible patients (n=520), 421 and 99 were classified in the Embolic and ICAS groups, respectively. Patients in the Embolic and ICAS groups had similar successful reperfusion rates with EVT (79.6% vs. 76.8%, P=0.537) and 3-month functional independence (54.5% vs. 45.5%, P=0.104). In multivariable analysis, ICAS-related occlusion (odds ratio, 0.495; 95% confidence interval, 0.269 to 0.913; P=0.024) showed poorer 3-month functional independence compared to embolic occlusion.

Conclusions

After EVT, patients with acute ICAS-related occlusion have relatively poor functional outcomes compared to those with embolic occlusion. Novel strategies need to be developed to improve EVT outcomes for ICAS occlusion.

Cerebral infarct volume measurements to improve patient selection for endovascular treatment

Patients who have large cerebral infarctions may not be good candidates for endovascular treatment. Various methods for determining infarct volume have been used in clinical studies. We evaluated the effectiveness of several methods for measuring infarct volume, especially regarding futile outcomes despite endovascular treatment.Patients with acute ischemic stroke in unilateral anterior circulation territory who were treated with intra-arterial thrombectomy were included. For assessing infarct volume, the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) scoring system was applied to images obtained by noncontrast computed tomography (NCCT), postcontrast CT (PCCT), and diffusion-weighted imaging (DWI). DWI stroke volume was semiquantitatively measured with the manually outlined hyperintense lesion. Infarct core volume was calculated with a threshold apparent diffusion coefficient value of 600 × 10 mm/s. Intraclass correlation coefficients (ICC) were estimated to assess inter-reader reliability for ASPECTS scoring and DWI stroke volume. Receiver operating characteristic (ROC) curve analyses, and univariable and multivariable comparative analyses, were performed with each evaluation method to predict futile outcome (modified Rankin Scale score 5-6).The mean age of the included 79 patients was 65.1 ± 15.7 years. Among them, 55 (69.6%) patients demonstrated successful reperfusion after intra-arterial thrombectomy, but 34 (43.0%) patients had futile outcomes. Inter-reader agreement was excellent for measurement of the DWI stroke volume (ICC, 0.973), DWI ASPECTS (0.940), and PCCT ASPECTS (0.859), but was moderate for NCCT ASPECTS (0.694). Regarding prediction of futile outcomes, area under ROC curve was 0.551 on NCCT ASPECTS and it was significantly smaller than that in PCCT ASPECTS (area under ROC 0.651, P = 0.030), DWI ASPECTS (0.733, P = 0.003), DWI stroke volume (0.702, P = 0.022), and infarct core volume (0.702, P = 0.021). Besides old age and high National Institutes of Health Stroke Scale score on admission, MRI parameters such as DWI ASPECTS and infarct core volume indicating large volumes were independently associated with futile outcomes in multivariable analyses.DWI ASPECTS can be a good parameter predicting futility, which is easily measured and has high prediction power.