A population-based incidence of M2 strokes indicates potential expansion of large vessel occlusions amenable to endovascular therapy

The enhanced reliability of higher national institute of health stroke scale thresholds over the conventional 6-point scale

INTRODUCTION

It is still uncertain if higher thresholds on National Institute of Health Stroke Scale (NIHSS) are better predictors of large infarctions than the conventional 6-point cutoff.

METHODS

We used 6-point and higher NIHSS thresholds including 8, 9, and 10-point to predict relative infarct areas, expressed as percentage of the affected hemisphere on axial brain computed tomography images, beginning at 5% with 5% increments each time until reaching the 40% cutoff for large infarctions, or achieving 100% sensitivity. Results were compared using area under the receiver operating characteristic curves (AUROC).

RESULTS

We enrolled 151 patients of acute ischemic stroke (Mean age: 62.88 years ± 12.71; Female: 48.34%). 77 patients (50.99%) exhibited left hemisphere strokes, while 74 (49%) had right hemisphere involvement. Sensitivity values of the 6-point for infarcts measuring 5%, 10%, 20%, 30%, and 40% were 62%, 64%, 77%, 82%, and 100%, respectively. At 40% infarct-size, 8-point achieved comparable results (52%, 55%, 69%, 76%, 100%), closely aligning with the 9-point (50%, 53%, 69%, 76%, 100%). The10-point was slightly trailing behind in sensitivity at 40% infarct-core (96%). Moreover, higher thresholds exhibited improved false-positive rates (FPR). At 40% infarct size, the FPRs of 6, 8, 9, and 10 points were 39%, 27%, 27%, and 21% respectively. Higher thresholds had augmented AUROC values (0.86, 0.86, 0.89) as compared to the 6-point (0.80). Logistic regression identified 14-point as definitive cutoff for large infarctions.

CONCLUSION

Higher thresholds can better differentiate small and medium infarcts as true-negatives and substantially reduce false-positive referrals for mechanical thrombectomy.

Population-based estimates suggest middle meningeal artery embolization for subdural hematomas could significantly expand the scope of neurovascular therapies

BACKGROUND

This study quantifies the impact of middle meningeal artery embolization (MMAE) for subdural hematomas (SDHs) by estimating a target population.

METHODS

A population-based study at a tertiary hospital, the main SDH facility for a four-county population, used primary ICD-10 codes over 3 years to collate SDH hospitalizations. Clinical and imaging data confirmed traumatic versus non-traumatic and acute versus non-acute (mixed or chronic) SDH. The MMAE-eligible population included patients with non-traumatic, non-acute SDH aged ≥18 years plus patients with 'traumatic' but non-acute SDH aged ≥60 years presenting with a fall. This was contrasted with the rate of large vessel strokes in the same population.

RESULTS

1279 hospitalizations with a primary ICD-10 SDH diagnosis were identified, with 389 from the study population. Excluding repeat admissions, 350 patients were analyzed, 233 (67%) traumatic, and 117 (33%) non-traumatic SDH. Regarding etiology, 'fall ≥60 years' was the most common category in the entire cohort (n=156; 45% (95% CI 39% to 50%)). The SDH rate was 52/100 000 persons/year (95% CI 47 to 57). The rate of all non-traumatic, non-acute SDH in patients aged ≥18 years was 17/100 000 persons/year (95% CI 15 to 20), combining with 'traumatic' but non-acute fall-related SDH in patients aged ≥60 years yielded 41/100 000 persons/year (95% CI 36 to 47). This demographic may represent an MMAE-eligible population, exceeding large vessel stroke rates (31/100 000 persons/year) in the same population, estimating 139 387 potential MMAE cases/year (95% CI 121 517 to 158 168) in the USA.

CONCLUSION

MMAE could transform non-acute SDH management, especially in the elderly, potentially surpassing the impact of large vessel stroke. Clinical trials are essential for validation of its efficacy and safety compared with standard management.

Updated estimates of large and medium vessel strokes, mechanical thrombectomy trends, and future projections indicate a relative flattening of the growth curve but highlight opportunities for expanding endovascular stroke care

BACKGROUND

A study was undertaken to determine the incidence of acute ischemic stroke (AIS) and strokes related to large (LVO) and medium (MVO) vessel occlusions, and to estimate annual mechanical thrombectomy (MT) volume, past trends and future growth.

METHODS

A population-based analysis was performed to estimate the rate of AIS, LVOs (internal carotid artery terminus, M1 branch of the middle cerebral artery, basilar artery) and MVOs (M2 and M3 branches of the middle cerebral artery, anterior and posterior cerebral arteries). MT estimates were determined from multiple governmental data sources. Annual US numbers were adjusted for population growth.

RESULTS

The incidence of AIS is estimated at 216 (95% CI 199 to 238)/100 000 persons/year or 718 191 (95% CI 661 483 to 791 121) AIS/year in the USA. A vascular occlusion was observed in 21% of patients with AIS (95% CI 15 to 29). The rate of LVO was 24/100 000 persons/year (95% CI 19 to 31) or 80 075 (95% CI 62 457 to 104 375) LVOs/year, and the rate of MVO was 20/100 000 persons/year or 65 798 (95% CI 45 555 to 95 110) MVOs/year. MT estimates for 2021 are 39 164 procedures with a flattening of the growth curve from 2019 (9%, 2020-2021; 4%, 2019-2020) as opposed to initial steep growth from 2015 to 2018. Current MT procedures represent 5% of all AIS, 27% of all vascular occlusions (LVO+MVO) and 38% of all LVO and M2 occlusions. The current trajectory indicates a future growth of 5-10%/year for the next several years.

CONCLUSION

A decline in MT growth is observed. The incidence of LVO+MVO is estimated at 44/100 000 persons/year or almost 144 000 large and medium vessel strokes annually. Of these, currently an estimated 27% undergo an MT procedure, indicating an opportunity for growth. Further expansion may require focusing on the elderly, medium vessel strokes and workflow efficiencies from diagnosis to treatment.

Endovascular therapy versus medical management for mild strokes due to medium and distal vessel occlusions

BACKGROUND

Distal and medium vessel occlusion (DMVO) strokes account for up to 40% of all acute ischemic strokes, many of which have a low initial deficit severity. Increasingly, endovascular treatment (EVT) is considered for these patients. However, there is a paucity of data comparing potential safety and efficacy of EVT versus best medical management (BMT) in these patients, particularly when presenting with mild symptoms.

METHODS

We retrospectively analyzed consecutive DMVO patients with NIHSS ≤6 who presented between January 2018 and December 2021 within 24 h from last seen well. We compared early and late clinical outcomes, as well as safety outcomes using multivariable linear and logistic regression analyses to determine whether EVT was independently associated with the outcomes of interest.

RESULTS

We included 80 subjects that fulfilled our study criteria (n = 41 BMT and n = 39 EVT). On adjusted analyses, when comparing EVT and BMT groups, there was no statistical difference in the NIHSS at discharge (Coefficient = -0.6, 95%-CI = -3.45-2.26, p = 0.678) or in the modified Rankin scale (mRS) at discharge (Coefficient = 0.37, 95%-CI = -0.52-1.25, p = 0.408). Furthermore, there was no difference in the 3-month mRS defined as good (mRS 0-2) (OR = 0.56, 95%-CI = 0.17-1.83, p = 0.341) or excellent (mRS 0-1) (OR = 0.45, 95%-CI = 0.15-1.34, p = 0.152). Finally, there was no difference in the incidence of all-type parenchymal hemorrhage (OR = 0.9, 95%-CI = 0.22-3.62, p = 0.879).

CONCLUSIONS

We found that among DMVO patients with low admission NIHSS treatment with EVT versus BMT was associated with similar outcomes. Larger prospective studies are required to confirm these findings.

A review of acute ischemic stroke caused by distal, medium vessel occlusions

Acute ischemic stroke (AIS) due to distal, medium vessel occlusion (DMVO) is increasingly recognized as the next frontier for mechanical thrombectomy. Distal, medium vessel occlusions are typically defined as an occlusion in the following arteries: anterior cerebral artery, M2-M4 segments of the middle cerebral artery, posterior cerebral artery, posterior inferior cerebellar artery, anterior inferior cerebellar artery, and superior cerebellar artery. It is estimated that 25-40% of all AIS is due to DMVO. Because of the large burden of DMVO, the frequency of literature published regarding these occlusions has greatly increased in recent years. Furthermore, treatment modalities have been created specifically for DMVOs. Due to the rapidly evolving literature on this topic, remaining up to date on DMVO definitions, anatomy, management, imaging, and clinical course is difficult. In this review article, we synthesized existing literature regarding the aforementioned topics and discussed future directions.

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

Introduction

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.

Methods

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.

Results

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.

Conclusion

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.

Automated occlusion detection for the diagnosis of acute ischemic stroke: A detailed performance review

INTRODUCTION

Stroke is a leading cause of adult disability and death worldwide. Automated detection of stroke on brain imaging has promise in a time critical environment. We present a method for the automated detection of intracranial occlusions on dynamic CT Angiography (CTA) causing acute ischemic stroke.

METHODS

We derived dynamic CTA images from CT Perfusion (CTP) data and utilised advanced image processing to enhance and display major cerebral blood vessels for symmetry analysis. We reviewed the performance of the algorithm on a cohort of 207 patients from the International Stroke Perfusion Imaging Registry (INSPIRE), with Large Vessel Occlusion (LVO) and non-LVO strokes. Included in the data were images with chronic stroke, various artefacts, incomplete vessel occlusions, and images of poorer quality. All images were annotated by stroke experts. In addition, each image was graded in terms of the difficulty of the task of occlusion detection. Performance was evaluated on the overall cohort, and with respect to occlusion location, collateral grade, and task difficulty. We also evaluated the impact of including additional perfusion data.

RESULTS

Images with a rating of lower difficulty achieved a sensitivity and specificity of 96% and 90%, respectively, while images with a moderate difficulty rating achieved 88% and 50%, respectively. For cases of high difficulty, where more than two experts or additional data were required to reach consensus, sensitivity and specificity was 53% and 11%. The addition of perfusion data to the dCTA images increased the specificity by 38%.

CONCLUSION

We have provided an unbiased interpretation of algorithm performance. Further developments include generalising to conventional CTA and employing the algorithm in a clinical setting for prospective studies.

Comparing Tigertriever 13 to other thrombectomy devices for distal medium vessel occlusion: A systematic review and meta-analysis

BACKGROUND

There is limited evidence on the optimal endovascular strategy for treatment of distal medium-vessel occlusions (DMVO). The low-profile Tigertriever 13 stent-triever shows early promise as an adaptable device that can navigate the distal vasculature without increasing complication risk in DMVO.

METHODS

Using Nested Knowledge, we screened literature for RCTs and cohort studies on the endovascular treatment of DMVO. The primary outcome was reperfusion success, as measured by thrombolysis in cerebral infarction (TICI) ≥ 2b and secondary outcomes included rate of symptomatic intracranial hemorrhage (sICH), mortality at 90 days, and modified Rankin scale (mRS) scores 0-2 at 90 days. A random-effects model was used to compute pooled prevalence rates and their corresponding 95% confidence intervals (CI).

RESULTS

Eleven studies with 1402 patients, 167 patients treated by Tigertriever 13 and 1235 patients treated by other devices, were included in the meta-analysis. The rate of reperfusion success was similar in patients treated by Tigertriever 13 (83.2% [95% CI: 71.5-96.7%]) versus other devices (81.6% [95% CI: 75.3-88.4%], p > 0.05). The rate of sICH was also similar in patients treated by Tigertriever 13 (7.2% [95% CI: 4.1-12.5%]) versus other devices (6.9% [95% CI: 5.5-8.8%]). There was significant heterogeneity in the reporting of mortality and mRS.

CONCLUSIONS

Tigertriever 13 had similar rates of reperfusion success and sICH as other devices used for the treatment of DMVO. Heterogeneity in data element reporting prevented further analyses. Further studies evaluating Tigertriever 13 and other potential devices in DMVO should attempt to harmonize data element reporting.

Endovascular treatment for acute M2 occlusion stroke within 6 hours-a retrospective real-world evidence

Background

We compared the efficacy and safety of endovascular therapy (EVT), intravenous (IV) thrombolysis and conservative treatment in M2 segment occlusion stroke based on a real-world database.

Methods

We retrospectively analyzed the database of admitted patients with M2 segment occlusion between January 2018 and December 2020. The patients who were eligible for reperfusion treatment were assigned to EVT, IV thrombolysis or conservative treatment according to the exact management proceeding. The primary outcome was a score of 0 and 1 on the modified Rankin scale (mRS) at 90 days. The odds ratio (OR) for the primary outcome was adjusted for age, baseline National Institute of Health Stroke Scale score, and door-to-treatment time. The secondary outcomes were based on a mRS score from 0 to 2 at 90 days and the safety outcomes including symptomatic intracranial hemorrhage, and all-cause mortality. The data were analyzed by the logistical regression model, including baseline adjustments.

Results

A total of 109 patients were included. Among them, 42 (38.5%) patients received EVT, 45 (42.5%) received IV thrombolysis and 22 (20.8%) received conservative treatment. The primary outcome based on a mRS score of 0 and 1, occurred in 66.7% of patients in the EVT group and 40% in the IV thrombolysis group (adjusted OR, 1.79; 95% confidence interval [CI], 1.19-2.68; P = 0.01). Symptomatic intracranial hemorrhage occurred in 1 patient (2.3%) in the EVT group and in 2 patients (4.4%) in the IV thrombolysis group (adjusted OR = 0.71, 95% CI: 0.13-4.07).

Conclusion

EVT showed better functional outcomes than IV thrombolysis and conservative treatment in moderate to severe acute stoke patients with M2 occlusion. There was no significant difference in the three groups concerning the incidence of symptomatic intracranial hemorrhage.

Outcomes after reperfusion therapies in patients with ACA stroke: A multicenter cohort study from the EVATRISP collaboration

BACKGROUND

Patients with stroke secondary to occlusions of the anterior cerebral artery (ACA) often have poor outcomes. The optimal acute therapeutic intervention for these patients remains unknown.

METHODS

Patients with isolated ACA-stroke were identified from 10 centers participating in the EndoVascular treatment And ThRombolysis in Ischemic Stroke Patients (EVATRISP) prospective registry. Patients treated with endovascular thrombectomy (EVT) were compared to those treated with intravenous thrombolysis (IVT). Odds ratios with 95% confidence intervals (OR; 95%CI) were calculated using multivariate regression analysis.

RESULTS

Included were 92 patients with ACA-stroke. Of the 92 ACA patients, 55 (60%) were treated with IVT only and 37 (40%) with EVT (±bridging IVT). ACA patients treated with EVT had more often wake-up stroke (24% vs. 6%, p = 0.044) and proximal ACA occlusions (43% vs. 24%, p = 0.047) and tended to have higher stroke severity on admission [NIHSS: 10.0 vs 7.0, p = 0.054). However, odds for favorable outcome, mortality or symptomatic intracranial hemorrhage did not differ significantly between both groups. Exploration of the effect of clot location inside the ACA showed that in patients with A1 or A2/A3 ACA occlusions the chances of favorable outcome were not influenced by treatment allocation to IVT or EVT.

DISCUSSION

Treatment with either IVT or EVT could be safe with similar effect in patients with ACA-strokes and these effects may be independent of clot location within the occluded ACA.

3D Turbo Spin-echo MRI-based Mechanical Thrombectomy at Middle Cerebral Artery Bifurcations

We describe three cases with acute middle cerebral artery (MCA) occlusion. From the pre-operative MRI, including three-dimensional turbo spin-echo sequences using T1WI and T2WI, we assessed both thrombus configuration and arterial anatomy at the MCA bifurcations. For efficient endovascular thrombectomy, we identified the applied MCA segment 2 (M2) branch, in which the main thrombus was buried. Sufficient recanalization after a single pass was achieved and the patients made a marked recovery. Although mechanical thrombectomy for M2 occlusion has not been of proven benefit, the endovascular procedure based on three-dimensional turbo spin-echo imaging is useful for more complete thrombus removal at MCA bifurcations.

Distribution of Diagnoses and Clinical and Imaging Characteristics in 1,322 Consecutive Suspected Stroke Patients

Background: Endovascular thrombectomy (EVT) has become the standard of care for large-vessel occlusion strokes, but several barriers for implementing an optimal organization of stroke management remain. Major issues include the lack of reliable data on the percentage of stroke patients potentially eligible for EVT especially in times of expanding indications for EVT. Our aim was therefore to study the frequencies of possible EVT-eligible patients such as patients with medium-vessel occlusions, patients with low Alberta Stroke Program Early Computed Tomography Scores (ASPECTS), patients presenting in an extended time window after onset of symptoms, and patients with mild symptoms at presentation (National Institutes of Health Stroke Scale, NIHSS ≤ 5). We also give detailed imaging and clinical information about the patients presenting with intracranial hemorrhage and other ischemic stroke mimics stratified by symptoms at presentation.

Methods: Cohort study of all consecutive patients with suspected acute stroke presenting to a tertiary care center in Germany between September 1, 2016, and August 31, 2017. Baseline and follow-up clinical and imaging characteristics were collected from patients' medical charts.

Results: Of 1,322 patients with a suspected acute stroke, 592 (44.8%) had ischemic strokes, 221 (16.7%) had hemorrhagic strokes, 190 (10.9%) had transient ischemic attacks (TIAs), and 319 (24.1%) were classified as stroke mimics. Stroke severity was mild (NIHSS ≤ 5) in 866 (65.5%) patients; 15.7% of the patients with an occlusion of the anterior circulation had an ASPECTS ≤ 5, 17.4% of the patients with an ischemic stroke had distal vessel occlusions, and 49% of the patients presented later than 6 h after onset of symptoms.

Conclusion: Our results help to plan resources in thrombectomy-capable centers in times of expanding indications for EVT where resources will have to be adjusted to patients with low-NIHSS, low-ASPECTS, and distal occlusions, and patients presenting in the extended time window, which may altogether account for an additional 20% of all ischemic stroke patients.

Mechanical thrombectomy for acute ischemic stroke with occlusion of the M2 segment of the middle cerebral artery: A literature review

Thanks to new generation devices, mechanical thrombectomy (MT) has substantially evolved and become the standard treatment for patients with acute occlusion of the internal carotid artery or proximal middle cerebral artery (MCA) (M1 segment). However, the role and benefit of MT in patients with distal MCA (M2 segment) occlusion remain unclear. Therefore, there is a need for further studies. To evaluate the efficacy and safety of MT for M2 occlusion, this article reviews the natural course of M2 occlusion, the evidence regarding MT for M2 segment occlusion, clinical outcomes of MT for M2 occlusion, and treatment outcomes according to device type.

Cost-effectiveness of endovascular thrombectomy in patients with acute stroke and M2 occlusion

BACKGROUND

The cost-effectiveness of endovascular thrombectomy (EVT) in patients with acute ischemic stroke due to M2 branch occlusion remains uncertain.

OBJECTIVE

To evaluate the cost-effectiveness of EVT compared with medical management in patients with acute stroke presenting with M2 occlusion using a decision-analytic model.

METHODS

A decision-analytic study was performed with Markov modeling to estimate the lifetime quality-adjusted life years and associated costs of EVT-treated patients compared with no-EVT/medical management. The study was performed over a lifetime horizon with a societal perspective in the Unites States setting. Base case, one-way, two-way, and probabilistic sensitivity analyses were performed.

RESULTS

EVT was the long-term cost-effective strategy in 93.37% of the iterations in the probabilistic sensitivity analysis, and resulted in difference in health benefit of 1.66 QALYs in the 65-year-old age groups, equivalent to 606 days in perfect health. Varying the outcomes after both strategies shows that EVT was more cost-effective when the probability of good outcome after EVT was only 4-6% higher relative to medical management in clinically likely scenarios. EVT remained cost-effective even when its cost exceeded US$200 000 (threshold was US$209 111). EVT was even more cost-effective for 55-year-olds than for 65-year-old patients.

CONCLUSION

Our study suggests that EVT is cost-effective for treatment of acute M2 branch occlusions. Faster and improved reperfusion techniques would increase the relative cost-effectiveness of EVT even further in these patients.

Middle Cerebral Artery M2 Thrombectomy in the STRATIS Registry

BACKGROUND AND PURPOSE

The safety and benefit of mechanical thrombectomy in the treatment of acute ischemic stroke patients with M2 segment middle cerebral artery occlusions remain uncertain. Here, we compare clinical and angiographic outcomes in M2 versus M1 occlusions in the STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) Registry.

METHODS

The STRATIS Registry was a prospective, multicenter, nonrandomized, observational study of acute ischemic stroke large vessel occlusion patients treated with the Solitaire stent-retriever as the first-choice therapy within 8 hours from symptoms onset. Primary outcome was defined as functional disability at 3 months measured by dichotomized modified Rankin Scale. Secondary outcomes included reperfusion rates and rates of symptomatic intracranial hemorrhage.

RESULTS

A total of 984 patients were included, of which 538 (54.7%) had M1 and 170 (17.3%) had M2 occlusions. Baseline demographics were well balanced within the groups, with the exception of mean baseline National Institutes of Health Stroke Scale score which was significantly higher in the M1 population (17.3±5.5 versus 15.7±5.0, P≤0.001). No difference was seen in mean puncture to revascularization times between the cohorts (46.0±27.8 versus 45.1±29.5 minutes, P=0.75). Rates of successful reperfusion (modified Thrombolysis in Cerebral Infarction≥2b) were similar between the groups (91% versus 95%, P=0.09). M2 patients had significantly increased rates of symptomatic ICH at 24 hours (4% versus 1%, P=0.01). Rates of good functional outcome (modified Rankin Scale score of 0-2; 58% versus 59%, P=0.83) and mortality (15% versus 14%, P=0.75) were similar between the 2 groups. There was no difference in the association of outcome and onset to groin puncture or onset to successful reperfusion in M1 and M2 occlusions.

CONCLUSIONS

In the STRATIS Registry, M2 occlusions achieved similar rates of successful reperfusion, good functional outcome, and mortality, although increased rates of symptomatic ICH were demonstrated when compared with M1 occlusions. The time dependence of benefit was also similar between the 2 groups. Further studies are needed to understand the benefit of mechanical thrombectomy for M2 occlusions.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02239640.

Advances in mechanical thrombectomy for acute ischaemic stroke from large vessel occlusions

Advances in endovascular treatment of acute ischaemic stroke from intracranial large vessel occlusions have continued in the past decade. Here, we performed a detailed review of all the new trials and studies that had the highest evidence, the guidelines for mechanical thrombectomy, the selection of the particular population outside the guidelines and endovascular therapeutic strategies for acute ischemic stroke from occluded intracranial arteries.

Correlations Between Physician and Hospital Stroke Thrombectomy Volumes and Outcomes: A Nationwide Analysis

[Figure: see text].

Effectiveness and safety of endovascular thrombectomy for large versus medium vessel occlusions: a single-center experience

BACKGROUND

The effectiveness and safety of endovascular thrombectomy (EVT) for medium vessel occlusions (MeVO) in the anterior intracranial circulation for patients with acute ischemic stroke (AIS) has yet to be definitively established. We compared outcomes in patients undergoing EVT for large vessel occlusion (LVO) versus those with MeVO.

METHODS

This retrospective cohort study, using an intention to treat design, compared the 90-day modified Rankin Scale (mRS) score between 43 patients with MeVO and 199 with LVO in the anterior intracranial circulation. Secondary outcome measures included vessel recanalization using the Thrombolysis in Cerebral Infarction (TICI) score, procedural complications, post-EVT intracranial hemorrhage (ICH), and infarct size.

RESULTS

The rate of good functional outcome (90-day mRS 0-2) was higher in patients with LVO than in those with MeVO (32.9% vs 27%), but this was not statistically significant (p=0.19). The rate of EVT procedural complications was also not significantly different between the groups (p=0.10), nor was the rate of ICH (p=0.30). There was also no significant difference in TICI scores between groups (p=0.12). Infarct size was larger in the LVO group (p<0.01). Multivariate analysis showed older age, not receiving recombinant tissue plasminogen activator (r-tPA), and larger infarct size were independent predictors of poor functional outcome at 90 days.

CONCLUSION

The 90-day mRS and rate of periprocedural complications were not significantly different between patients treated for LVO and those treated for MeVO with EVT. Older age, not receiving r-tPA, and larger infarct size were independent predictors of poor outcome at 90 days.

Triage and systems of care in stroke

There has been increasing adoption of endovascular stroke treatment in the United States following multiple clinical trials demonstrating superior efficacy. Next steps in enhancing this treatment include an analysis and development of stroke systems of care geared toward efficient delivery of endovascular and comprehensive stroke care. The chapter presents epidemiological data and an overview of the current state of stroke delivery and potential improvements for the future in the light of clinical data.

Nationwide Analysis of Endovascular Thrombectomy Provider Specialization for Acute Stroke

Background and Purpose:

Determine the extent of cerebrovascular expertise among the specialties of proceduralists providing endovascular thrombectomy (ET) for emergent large vessel occlusion stroke in the modern era of acute stroke among Medicare beneficiaries

Methods:

Retrospective cohort study using validated International Classification of Diseases, Tenth Revision , Clinical Modification codes to identify admissions with acute ischemic stroke and treatment with ET. We identified proceduralist specialty by linking the National Provider Identifier provided by Medicare to the specialty listed in the National Provider Identifier database, grouping into radiology, neurology, neurosurgery, other surgical, and internal medicine. We calculated the number of proceduralists and hospitals who performed ET, ET team specialty composition by hospital, and number of proceduralists who performed ET at multiple hospitals.

Results:

Forty-two percent (n=5612) of ET were performed by radiology-background proceduralists, with unclear knowledge of how many were cerebrovascular specialists. Neurosurgery- and neurology-background interventionalists performed fewer but substantial numbers of cases, accounting for 24% (n=3217) and 23% (n=3124) of total cases, respectively. ET teams included a neurology- or neurosurgery-background proceduralist at 65% (n=407) of hospitals that performed ET and included both in 26% (n=160) of teams.

Conclusions:

Almost two-thirds of ET teams nationwide include a neurology- or neurosurgery-background proceduralist and higher volume centers in urban areas were more likely to have neurology- or neurosurgery-background proceduralists with cerebrovascular expertise on their team. It is unclear how many radiology-background interventionalists are cerebrovascular specialists versus generalists. Significant work remains to be done to understand the impact of proceduralist specialty, training, and cerebrovascular expertise on ET outcomes.

Benefit of endovascular thrombectomy for M2 middle cerebral artery occlusion in the ARISE II study

Background

The benefit of endovascular thrombectomy for acute ischemic stroke with M2 segment middle cerebral artery occlusion remains controversial, with uncertainty and paucity of data specific to this population.

Objective

To compare outcomes between M1 and M2 occlusions in the Analysis of Revascularization in Ischemic Stroke with EmboTrap (ARISE II) trial.

Methods

We performed a prespecified analysis of the ARISE II trial with the primary outcome of 90-day modified Rankin Scale score of 0–2, which we termed good outcome. Secondary outcomes included reperfusion rates and major adverse events. The primary predictor was M2 occlusion, which we compared with M1 occlusion.

Results

We included 183 patients, of whom 126 (69%) had M1 occlusion and 57 (31%) had M2 occlusion. There was no difference in the reperfusion rates or adverse events between M2 and M1 occlusions. The rate of good outcome was not different in M2 versus M1 occlusions (70.2% vs 69.7%, p=0.946). In a logistic regression model adjusted for age, sex, and baseline National Institutes of Health Stroke Scale score, M2 occlusions did not have a significantly different odds of good outcome compared with M1 occlusions (OR 0.94, 95% CI 0.47 to 1.88, p=0.87).

Conclusion

In ARISE II, M2 occlusions achieved a 70.2% rate of good outcome at 90 days, which is above published rates for untreated M2 occlusions and superior to prior reports of M2 occlusions treated with endovascular thrombectomy. We also report similar rates of good outcome, successful reperfusion, death, and other adverse events when comparing the M1 and M2 occlusions.

Performance of Automated Attenuation Measurements at Identifying Large Vessel Occlusion Stroke on CT Angiography

PURPOSE

Computed tomography angiography (CTA) is routinely used to detect large-vessel occlusion (LVO) in patients with suspected acute ischemic stroke; however, visual analysis is time consuming and prone to error. To evaluate solutions to support imaging triage, we tested performance of automated analysis of CTA source images (CTASI) at identifying patients with LVO.

METHODS

Stroke patients with LVO were selected from a prospectively acquired cohort. A control group was selected from consecutive patients with clinically suspected stroke without signs of ischemia on CT perfusion (CTP) or infarct on follow-up. Software-based automated segmentation and Hounsfield unit (HU) measurements were performed on CTASI for all regions of the Alberta Stroke Program Early CT score (ASPECTS). We derived different parameters from raw measurements and analyzed their performance to identify patients with LVO using receiver operating characteristic curve analysis.

RESULTS

The retrospective analysis included 145 patients, 79 patients with LVO stroke and 66 patients without stroke. The parameters hemispheric asymmetry ratio (AR), ratio between highest and lowest regional AR and M2-territory AR produced area under the curve (AUC) values from 0.95-0.97 (all p < 0.001) for detecting presence of LVO in the total population. Resulting sensitivity (sens)/specificity (spec) defined by the Youden index were 0.87/0.97-0.99. Maximum sens/spec defined by the specificity threshold ≥0.70 were 0.91-0.96/0.77-0.83. Performance in a small number of patients with isolated M2 occlusion was lower (AUC: 0.72-0.85).

CONCLUSION

Automated attenuation measurements on CTASI identify proximal LVO stroke patients with high sensitivity and specificity. This technique can aid in accurate and timely patient selection for thrombectomy, especially in primary stroke centers without CTP capacity.

Thrombectomy for Distal, Medium Vessel Occlusions: A Consensus Statement on Present Knowledge and Promising Directions

Endovascular thrombectomy (EVT) is well established as a highly effective treatment for acute ischemic stroke (AIS) due to proximal, large vessel occlusions (PLVOs). With iterative further advances in catheter technology, distal, medium vessel occlusions (DMVOs) are now emerging as a promising next potential EVT frontier. This consensus statement integrates recent epidemiological, anatomic, clinical, imaging, and therapeutic research on DMVO-AIS and provides a framework for further studies. DMVOs cause 25% to 40% of AISs, arising as primary thromboemboli and as unintended consequences of EVT performed for PLVOs, including emboli to new territories (ENTs) and emboli to distal territories (EDTs) within the initially compromised arterial field. The 6 distal medium arterial arbors (anterior cerebral artery [ACA], M2–M4 middle cerebral artery [MCA], posterior cerebral artery [PCA], posterior inferior cerebellar artery [PICA], anterior inferior cerebellar artery [AICA], and superior cerebellar artery [SCA]) typically have 25 anatomic segments and give rise to 34 distinct arterial branches nourishing highly differentiated, largely superficial cerebral neuroanatomical regions. DMVOs produce clinical syndromes that are highly heterogenous but frequently disabling. While intravenous fibrinolytics are more effective for distal than proximal occlusions, they fail to recanalize one-half to two-thirds of DMVOs. Early clinical series using recently available, smaller, more navigable stent retriever and thromboaspiration devices suggest EVT for DMVOs is safe, technically efficacious, and potentially clinically beneficial. Collaborative investigations are desirable to enhance imaging recognition of DMVOs; advance device design and technical efficacy; conduct large registry studies using harmonized, common data elements; and complete formal randomized trials, improving treatment of this frequent mechanism of stroke.

Incidence of Acute Ischemic Stroke With Visible Arterial Occlusion

Background and Purpose:

Because of several methodological limitations, previous studies focusing on the prevalence of large vessel occlusion in ischemic stroke (IS) patients provided conflicting results. We evaluated the incidence of IS with a visible arterial occlusion using a comprehensive population-based registry.

Methods:

Patients with acute IS were prospectively identified among residents of Dijon, France, using a population-based registry (2013–2017). All arterial imaging exams were reviewed to assess arterial occlusion. Annual incidence rates of IS (first-ever and recurrent events) and IS with a visible occlusion were calculated.

Results:

One thousand sixty cases of IS were recorded (mean age: 76.0±15.8 years, 53.9% women). Information about arterial imaging was available in 971 (91.6%) of them, and only preexisting dementia was independently associated with having missing information (odds ratio=0.34 [95% CI, 0.18–0.65], P =0.001). Among these patients, 284 (29.2%) had a visible arterial occlusion. Occlusion site was the anterior circulation in 226 patients (23.3% of overall patients with available data) and the posterior circulation in 58 patients (6.0%). A proximal occlusion of the anterior circulation was observed in 167 patients (17.2%). The crude annual incidence rate of total IS per 100 000 was 138 (95% CI, 129–146). Corresponding standardized rates were 66 (95% CI, 50–82) to the World Health Organization and 141 (95% CI, 118–164) to the 2013 European populations. The crude annual incidence rate of IS with a visible arterial occlusion per 100 000 was 37 (95% CI, 33–41) and that of IS with a proximal occlusion of the anterior circulation was 22 (95% CI, 18–25). Corresponding standardized rates were 18 (95% CI, 10–26) and 10 (95% CI, 8–13) to the World Health Organization population, and 38 (95% CI, 26–50) and 23 (95% CI, 19–26) to the 2013 European population, respectively.

Conclusions:

These results will be helpful to plan the need for thrombectomy-capable stroke center resources.

Increased Rate of Successful First Passage Recanalization During Mechanical Thrombectomy for M2 Occlusion

BACKGROUND

Mechanical thrombectomy (MT) is the standard of care for the treatment of acute ischemic stroke (AIS) caused by anterior circulation large-vessel occlusion. However, the true safety and efficacy of MT in medium-size vessel occlusions such as the M2 segment of the middle cerebral artery have yet to be completely defined. In this study, we analyze the safety and efficacy of MT in M2 occlusions compared with M1 occlusions.

METHODS

A retrospective analysis was performed of patients with AIS secondary to M1 and M2 occlusions between 2011 and 2018. The inclusion criteria were 1) AIS secondary to M1 or M2 occlusion, 2) MT performed by stentrieval technique alone, aspiration technique, or combined stentrieval-aspiration techniques. Basic patient characteristics, number of passages, first passage recanalization success (≥TICI [Thrombolysis in Cerebral Ischemia] grade 2b), total recanalization success, hemorrhagic complications (including intracerebral hemorrhage [ICH] and subarachnoid hemorrhage), and clinical outcomes were compared between both groups.

RESULTS

Two hundred and sixty patients met the inclusion criteria; 171 patients had M1 occlusion versus 89 with M2 occlusion. First passage recanalization success rate was significantly higher in the M2 group (55.1% vs. 39.2%; P = 0.015). Total recanalization success rate was higher in the M2 group but did not reach significance (83% vs. 75%; P = 0.128). Subarachnoid hemorrhage rate was significantly higher in the M2 group (25% vs. 12%; P = 0.010) but there was no difference for ICH complications (14.6% vs. 16.4%; P = 0.711).

CONCLUSIONS

MT for M2 occlusions has similar overall efficacy to that for M1 occlusions, but with higher first-pass successful recanalization rates. MT for M2 occlusions has a higher risk of associated subarachnoid hemorrhage.

Radiology workload in clinical implementation of thrombectomy for acute ischemic stroke: experience from The Netherlands

PURPOSE

To investigate the number of acute stroke patients undergoing CT angiography (CTA) for suspected large vessel occlusion (LVO) and those eligible for thrombectomy in relation to the population.

METHODS

Consecutive patients in a Western population who underwent CTA for suspected LVO of the proximal anterior circulation between January and August 2019 were included. The date and time of CTA and the number of patients eligible for thrombectomy were assessed. Our hospital's service area population was estimated using the Central Bureau for Statistics data. One-way analysis of variance with post-hoc tests and chi-squared tests were used for statistical analyses.

RESULTS

Of 520 patients (49% males, mean age of 72 years) undergoing CTA, 84 (16.2%) were eligible for thrombectomy. Our hospital's service area population was estimated at 420,000. Therefore, 3.6 CTA scans were performed and 0.6 patients were eligible for thrombectomy per 100,000 people per week. The number of patients undergoing CTA and the number of patients eligible for thrombectomy both did not significantly differ between any days of the week (P > 0.05). A total of 236 (45%) and 284 patients (55%) underwent CTA during office and on-call hours, respectively. The percentage of patients eligible for thrombectomy did not significantly differ between office and on-call hours (P = 0.834).

CONCLUSION

Our study estimated the number of stroke patients undergoing CTA for suspected LVO and those eligible for thrombectomy in relation to the population. Numbers were essentially the same throughout the week, and during office and on-call hours. Our data can be used to make adequate staffing plans.

Neuroanatomy of the middle cerebral artery: implications for thrombectomy

Our perspective on anatomy frequently depends on how this anatomy is utilized in clinical practice, and by which methods knowledge is acquired. The thrombectomy revolution, of which the middle cerebral artery (MCA) is the most common target, is an example of a clinical paradigm shift with a unique perspective on cerebrovascular anatomy. This article reviews important features of MCA anatomy in the context of thrombectomy. Recognizing that variation, frequently explained by evolutionary concepts, is the rule when it comes to branching pattern, vessel morphology, territory, or collateral potential is key to successful thrombectomy strategy.

Endovascular Treatment Decisions in Patients with M2 Segment MCA Occlusions

BACKGROUND AND PURPOSE

Endovascular therapy in acute ischemic stroke is rapidly evolving. We explored physicians' treatment attitudes and practice in patients with acute ischemic stroke due to M2 occlusion, given the absence of Level-1 guidelines.

MATERIALS AND METHODS

We conducted an international multidisciplinary survey among physicians involved in acute stroke care. Respondents were presented with 10 of 22 case scenarios (4 with proximal M2 occlusions and 1 with a small-branch M2 occlusion) and asked about their treatment approach under A) current local resources, and B) assumed ideal conditions (no monetary or infrastructural restraints). Overall treatment decisions were evaluated; subgroup analyses by physician and patient baseline characteristics were performed.

RESULTS

A total of 607 physicians participated. Most of the respondents decided in favor of endovascular therapy in M2 occlusions, both under current local resources and assumed ideal conditions (65.4% versus 69.6%; P = .017). Under current local resources, older patient age (P < .001), longer time since symptom onset (P < .001), high center endovascular therapy volume (P < .001), high personal endovascular therapy volume (P = .005), and neurosurgeons (P < .001) were more likely to favor endovascular therapy. European respondents were less likely to favor endovascular therapy (P = .001). Under assumed ideal conditions, older patient age (P < .001), longer time since symptom onset (P < .001), high center endovascular therapy volume (P = .041), high personal endovascular therapy volume (P = .002), and Asian respondents were more likely to favor endovascular therapy (P = .037). Respondents with more experience (P = .048) and high annual stroke thrombolysis treatment volume (P = .001) were less likely to favor endovascular therapy.

CONCLUSIONS

Patients with M2 occlusions are considered appropriate candidates for endovascular therapy by most respondents in this survey, especially by those performing endovascular therapy more often and those practicing in high-volume centers.

Large Vessel Occlusion in Acute Ischemic Stroke Patients: A Dual-Center Estimate Based on a Broad Definition of Occlusion Site

BACKGROUND

Accurate assessment of the frequency of large vessel occlusion (LVO) is important to determine needs for neurointerventionists and thrombectomy-capable stroke facilities. Current estimates vary from 13% to 52%, depending on acute ischemic stroke (AIS) definition and methods for AIS and LVO determination. We sought to estimate LVO prevalence among confirmed and suspected AIS patients at 2 comprehensive US stroke centers using a broad occlusion site definition: internal carotid artery (ICA), first and second segments of the middle cerebral artery (MCA M1,M2), the anterior cerebral artery, vertebral artery, basilar artery, or the proximal posterior cerebral artery.

METHODS

We analyzed prospectively maintained stroke databases of patients presenting to the centers between January and December 2017. ICD-10 coding was used to determine the number of patients discharged with an AIS diagnosis. Computed tomography angiography (CTA) or magnetic resonance angiography (MRA) was reviewed to determine LVO presence and site. Percentages of patients with LVO among the confirmed AIS population were reported.

RESULTS

Among 2245 patients with an AIS discharge diagnosis, 418 (18.6%:95% confidence interval [CI] 17.3%-20.0%) had LVO documented on CTA or MRA. Most common occlusion site was M1 (n=139 [33.3%]), followed by M2 (n=114 [27.3%]), ICA (n=69[16.5%]), and tandem ICA-MCA lesions (n=44 [10.5%]). Presentation National Institutes of Health Stroke Scale scores were significantly different for different occlusion sites (P=.02).

CONCLUSIONS

The LVO prevalence in our large series of consecutive AIS patients was 18.6% (95% CI 17.3%-20.0%). Despite the use of a broad definition, this estimate is less than that reported in most previous studies.

Outcomes associated with endovascular treatment among patients with acute ischemic stroke in the USA

BACKGROUND

Few studies have examined the trends in clinical and economic outcomes of patients with acute ischemic stroke (AIS) who receive endovascular therapy (ET) in the real-world setting.

OBJECTIVE

To evaluate characteristics and trends in clinical and economic outcomes among commercially insured patients with AIS undergoing ET between 2011 and 2017.

METHODS

Patients with AIS undergoing ET from January 1, 2011 to June 30, 2017 were identified from administrative claims contained in the IBM MarketScan Commercial and Medicare Supplemental databases. The Mann-Kendall trend test was performed to examine clinical and economic trends.Between 2011 and 2017, 3411 patients (mean age 62.85±15 years) with a primary diagnosis of AIS underwent ET (coverage: Commercial 59%, n=2008; Medicare Supplemental 41%, n=1403). In the Commercial cohort, discharge to home increased significantly (from 29.54% to 39.18%, p<0.05). Length of stay declined significantly among the overall cohort (from 10.96 to 9.05 days, p<0.01) and the Medicare Supplemental cohort (from 10.03 to 8.43 days, p<0.05). All-cause 365-day readmission decreased significantly among the overall cohort (from 47.5% to 36.7%, p<0.05) and the Commercial cohort (from 51.54% to 36.43%, p<0.05) but remained unchanged in the Medicare Supplemental cohort. While index procedure cost did not change significantly ($93 955 to $87 906, p=0.8806), total cost significantly declined in the overall cohort (from $166 922 to $130 678, p<0.05).

CONCLUSIONS

Although with some variation across the samples studied, outcomes including discharge to home, length of stay, readmission, and total cost associated with endovascular stroke therapy seemed to have improved between 2011 and 2017. Index admission cost remained unchanged.

Effect of definition and methods on estimates of prevalence of large vessel occlusion in acute ischemic stroke: a systematic review and meta-analysis

Introduction

Accurate estimation of the incidence of large vessel occlusion (LVO) is critical for planning stroke systems of care and approximating workforce requirements. This systematic review aimed to estimate the prevalence of LVO among patients with acute ischemic stroke (AIS), with emphasis on definitions and methods used by different studies.

Methods

A systematic literature review was performed to search for articles on the prevalence of LVO and AIS. All articles describing the frequency of LVO frequency among AIS patients were included. Studies without consecutive recruitment or confirmation of LVO with CT angiography or MR angiography were excluded. Heterogeneity of the studies was assessed; meta-regression was performed to estimate the effect of LVO definition and study methods on LVO prevalence.

Results

18 articles met the inclusion criteria: 5 studies presented population based estimates; 13 provided single hospital experiences (5 prospective, 8 retrospective). The AIS denominator (number of all AIS) from which LVO rates were generated was variable. Nine different definitions were used, based on occlusion site. Significant heterogeneity existed among the studies (I2=99%, P<0.001). The prevalence of LVO among patients with suspected AIS ranged from 13% to 52%. Overall prevalence was 30.0% (95% CI 25.0% to 35.0%). Pooled prevalence of LVO among suspected AIS patients was 21% (95% CI 19% to 30%). Based on meta-regression, the method of AIS denominator determination significantly influenced heterogeneity (P=0.018).

Conclusion

The heterogeneity of LVO estimates was remarkably high. The method of AIS denominator determination was the most significant predictor of LVO estimates. Studies with a standardized LVO definition and methods of AIS estimation are necessary to estimate the true prevalence of LVO among patients with AIS.

National trends in endovascular therapy for acute ischemic stroke: utilization and outcomes

Objective

Following widespread acceptance of endovascular therapy (ET) for large vessel occlusion stroke in 2015, we assessed nationwide utilization of revascularization for acute ischemic stroke (AIS).

Methods

We utilized the 2013–2016 Healthcare Cost and Utilization Project Nationwide Readmissions Database. We identified AIS admissions, treatment with intravenous thrombolysis (IVT), ET, and vascular risk factors using International Classification of Disease Clinical Modification codes. Main predictor of outcome was the time period of index admission (‘pre-endovascular era (pre-EA)’ January 2013–January 2015 and ‘endovascular era (EA)’ February 2015– December 2016). We calculated the proportion of AIS admissions in which, first, VT and second, ET was performed. Among patients treated with ET, we examined the association between era and discharge disposition, in-hospital mortality during index admission, and 30-day readmission.

Results

There were 925 363 index AIS admissions before the EA and 857 347 during. A higher proportion of AIS patients received IVT (8.4% vs 7.8%) and ET (2.6% vs 1.3%) in the EA. Although length of stay (LOS) was shorter in the EA (5.70 vs 6.80 days), total charges were greater ($56 691 vs $53 878), and admissions were more often to a metropolitan hospital (65.2% vs 57.2%). Among those treated with ET, a smaller proportion received IVT (29.7% vs 44.9%), LOS was substantively shorter (9.75 vs 12.76 days), and patients had a lower odds of discharge home.

Conclusions

The utilization of ET has doubled in the EA but ET remains underutilized. ET is predominantly provided at metropolitan teaching hospitals and associated with higher charges despite shorter LOS and unchanged in-hospital mortality.

A comparative analysis of 3MAX aspiration versus 3 mm Trevo Retriever for distal occlusion thrombectomy in acute stroke

Background

Although aspiration and stent retriever thrombectomy perform similarly in proximal occlusions, no comparative series are available in distal occlusions. We aimed to compare the 3 mm Trevo Retriever against the 3MAX thromboaspiration catheter in distal arterial occlusions.

Methods

A single-center retrospective review of a prospectively maintained databank for patients treated with the 3 mm Trevo stent retriever or 3MAX thromboaspiration as the upfront approach for distal occlusions (middle cerebral artery mid/distal M2/M3, anterior cerebral artery A1/A2/A3 or posterior cerebral artery P1/P2) from January 2014 to July 2018 was performed. The primary outcome was the rate of distal occlusion first-pass reperfusion (modified Thrombolysis in Cerebral Infarction (mTICI) 2b–3).

Results

Of 1100 patients treated within the study period, 137 patients/144 different arteries were treated with the 3 mm Trevo (n=92) or 3MAX device (n=52). The groups had comparable demographics and baseline characteristics. There was a higher rate of first-pass mTICI 2b–3 reperfusion (62% vs 44%; p=0.03), a trend towards a higher rate of final mTICI 2b–3 reperfusion (84% vs 69%; p=0.05), and lower use of adjuvant therapy (15% vs 31%; p=0.03) with the 3 mm Trevo compared with the 3MAX. The median number of passes (p=0.46), frequency of arterial spasm (p=1.00), rates of parenchymal hematomas (p=0.22)/subarachnoid hemorrhage (p=0.37) in the territory of the approached vessel were similar across the two groups. The 90-day rate of good outcomes (45% vs 46% in the 3 mm Trevo and 3MAX groups, respectively; p=0.84) was comparable. Multivariable regression identified baseline NIH Stroke Scale (NIHSS) score (OR 0.9; 95% CI 0.8 to 0.97; p<0.01) and use of 3 mm Trevo (OR 2.2; 95% CI 1.1 to 4.6; p=0.02) independently associated with first-pass mTICI 2b–3 reperfusion.

Conclusions

In the setting of distal arterial occlusions, the 3 mm Trevo may lead to higher rates of first-pass reperfusion than direct 3MAX thromboaspiration. Lower NIHSS was found to be associated with improved reperfusion rates as observed in more proximal lesions. Further studies are warranted.

A national economic and clinical model for ischemic stroke care development in Saudi Arabia: A call for change

BACKGROUND

Stroke is a significant burden in Saudi Arabia and the Saudi Ministry of Health's stroke committee has identified an urgent need to improve care.

AIM

The purpose of this study was to undertake a health-economic analysis to quantify the impact of developing stroke care in the country.

METHODS

An economic model was developed to assess the costs and clinical outcomes associated with an ischemic stroke care development program compared with current stroke care. Based on Saudi epidemiological data, cohorts of ischemic stroke patients enter the model each year for the first 10 years based on increasing incidence. Four treatment options were modeled including reperfusion and non-reperfusion treatments. The development scenario estimates the impact of gradually increasing uptake of more effective treatments over 10 years. Changes in the stroke care organization are considered along with resources required to increase capacity, allowing more patients to be admitted to stroke hospitals and access effective treatments.

RESULTS

The stroke care development program is associated with an increase in functionally independent patients and a decrease in disabling strokes compared with current stroke care. Additionally, the development program is associated with estimated cost savings of $602 million over 15 years ($255 million direct costs, $348 million indirect costs).

CONCLUSIONS

The model predicts that the stroke care development program is associated with improved patient outcomes and lower overall costs compared with the current stroke care program.

Thrombectomy for M2 occlusions and the role of the dominant branch

INTRODUCTION

The benefits of thrombectomy for occlusion of M2 segments remain controversial. The aim of this study is to assess thrombectomy's efficacy and safety in patients with M2 segment occlusion and associations between occlusion sites and anatomic variations of M1 division.

MATERIALS AND METHODS

A prospective series of 30 patients with acute ischemic stroke (AIS) resulting from M2 segment occlusion of the middle cerebral artery (MCA) who underwent thrombectomy was analyzed. The primary endpoint was assessed by the Extended Treatment in Cerebral Infarction scale (eTICI). The secondary endpoints were the incidence of symptomatic hemorrhagic transformation (sICH), mortality and good functional outcome at three months.

RESULTS

The mean patient age was 69.2 years. The mean National Institutes Health Stroke Scale score (NIHSS) upon hospital admission was 16. The recanalization rates were eTICI 2b/3 in 90% and 2c/3 in 60% of the patients. Total recanalization of the M2 branch was achieved in 53% of patients. sICH incidence was 6.6%, the mortality rate was 30%, and a good functional outcome (mRS ≤2) was observed in 50% of the patients. Twenty-seven patients (90%) had a dominant M2 branch and all were occluded. Regarding the site of M2 occlusions, 74% of patients had proximal M2 occlusions.

CONCLUSIONS

Thrombectomy appears to be a safe and effective method for the treatment of acute M2 segment occlusions of the MCA. Most of the cases had a dominant M2 branch, and all of them were occluded. Larger studies are needed to verify the benefits of thrombectomy for different settings of M2 occlusions.

Endovascular therapy for middle cerebral artery M2 segment occlusion: subanalyses of RESCUE-Japan Registry 2

OBJECTIVE

To compare the efficacy of endovascular therapy (EVT) with that of medical treatment in 'real-world 'patients with M2 occlusion.

METHODS

This was a post hoc analysis of the Recovery by Endovascular Salvage for Cerebral Ultra-acute Embolism Japan Registry 2. Among 2420 patients in the registry, we evaluated patients with isolated M2 occlusion and those with functional independence before the stroke. Multivariable logistic regression analysis was used to evaluate and compare clinical outcomes between EVT and medical treatment. Additional propensity score-matched (PSM) analyses were performed. We performed subgroup analyses of the primary outcome (modified Rankin Scale score 0-2 at 90 days) using forest plots of treatment effects.

RESULTS

Overall, 372 patients with M2 occlusion (n=184 EVT; n=188, medical treatment) were evaluated. The EVT group had a higher baseline National Institutes of Health Stroke Scale score (median (IQR), 15 [9-19] vs 10 [5-16]) and earlier onset to hospital door time (110 [50-258] vs 150 [60-343] min) than the medical treatment group. After adjustment, EVT was significantly associated with higher odds of primary outcome (adjusted OR=2.09; 95% CI 1.26 to 3.47) and lower odds of mortality at 90 days (adjusted OR= 0.27; 95% CI 0.08 to 0.93). After PSM analyses (184 patients were 1:1 matched with each group), EVT was effective and safe relative to medical treatment. Effects favoring EVT were present in several subgroups of interest.

CONCLUSION

In patients with M2 occlusion, our registry suggests that EVT is effective and safe.

Burden of large vessel occlusion stroke and the service gap of thrombectomy: A population-based study using a territory-wide public hospital system registry

Background

Ischemic stroke due to large vessel occlusion can be effectively treated with thrombectomy but access to this treatment is limited in many parts of the world. Local incidence of large vessel occlusion is critical in determining the development of thrombectomy service, but reliable data from Asian countries are lacking.

Aims

We performed a population-based study to estimate the burden of large vessel occlusion and the service gap for thrombectomy in Hong Kong.

Methods

All acute ischemic stroke patients admitted in 2016 to the public healthcare system, which provided 90% of the emergency healthcare in the city, was identified from the Hong Kong Hospital Authority’s central electronic database. The diagnosis of large vessel occlusion was retrospectively verified by two independent cerebrovascular specialists in a randomly sampled cohort based on clinical and neuroimaging data. The incidence of large vessel occlusion in the population was estimated through weighting the sample results and compared with the thrombectomy data in the same period.

Results

There were 6859 acute ischemic stroke patients treated in the public health system in 2016. Amongst the 300 patients randomly sampled according to diagnosis coding, 130 suffered from anterior circulation large vessel occlusion. This translated to 918 patients (95% CI 653–1180) and 13.3% of all ischemic stroke patients. The estimated incidence of anterior circulation large vessel occlusion was 12.5 per 100,000 persons per year (95% CI 11.7–13.4). Large vessel occlusion stroke patients were more commonly female than male (67.4% vs. 31.6%, p = 0.003), and were older than non-large vessel occlusion stroke patients (mean of 80.5 years vs. 71.4 years, p = < 0.001). They also had higher 30-day mortality rate (31.1% vs. 4.6%, p = < 0.001), and longer hospital stay (mean 38.6 vs. 21.1 days, p = 0.003) than non-large vessel occlusion stroke. In the same period, 83 thrombectomies for large vessel occlusion were performed, representing 9.1% of the estimated large vessel occlusion incidence.

Conclusion

The estimated incidence of anterior circulation large vessel occlusion in the Hong Kong Chinese population is lower than that in the West. There is however a substantial service gap for endovascular thrombectomy with less than 10% of large vessel occlusion patients receiving thrombectomy.