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

Endovascular therapy versus best medical care for acute ischemic stroke with distal medium vessel occlusion: a systematic review and meta-analysis

BACKGROUND

With the refinement of catheter technology, distal medium vessel occlusions (DMVOs) are now viewed as amenable to endovascular treatment (EVT) but its efficacy and safety remains unclear in AIS patients with DMVO.

METHODS

We conducted a systematic search of PubMed, Embase databases and Cochrane Library up to December 2023 using keywords to identify studies comparing EVT versus BMT in AIS with DMVOs. The assessed clinical outcomes were excellent functional outcome, good functional outcome, 90-day mortality, symptomatic intracranial hemorrhage (sICH), and early neurological improvement (ENI) after treatment.

RESULTS

Overall, 31 studies were included. There were no significant differences in excellent functional outcome (OR: 1.21, 95% CI: 0.99-1.47), good functional outcome (OR: 1.03, 95% CI: 0.82-1.30) and 90-day mortality (OR: 1.17, 95% CI: 0.84-1.62). Additionally, EVT led to higher sICH (OR: 1.64, 95% CI: 1.09-2.47) and better ENI (OR: 1.50, 95% CI: 1.02-2.19) compared to BMT. In individuals with M2 occlusion receiving EVT showed better excellent functional outcomes (OR: 1.48, 95% CI: 1.07-2.03). Those patients with PCA occlusion showed no significant difference in functional outcomes. In individuals with ACA occlusion, EVT resulted in reduced functional independence (OR: 0.55, 95% CI: 0.31-0.98). For NIHSS < 6, BMT achieved better functional independence compared to EVT (OR: 0.71, 95% CI: 0.51-0.98) and EVT showed higher sICH (OR: 3.44, 95% CI: 1.42-8.31).

CONCLUSION

For patients with AIS and DMVO occlusion, EVT fails to improve functional prognosis while increasing sICH incidence. More randomized controlled trials are needed in the future to confirm these results.

Flow Diversion for the Treatment of Middle Cerebral Artery Aneurysms

The invention of flow diverting stents (FDS) is a novel milestone in the field of endovascular aneurysm therapy, promoting physiological healing of the vessel segment contrary to prior deconstructive treatment strategies, such as coiling. The effects of FDS are based on changes in flow patterns, segmental wall stabilization, and the growth of a neointima. Although flow diversion is already well established for cerebral aneurysms in proximal segments, peripheral locations remain challenging. Especially the middle cerebral artery (MCA) with its predominance of non-collateralized perforators and functional end arteries that supply the eloquent areas of the brain is of major concern.The literature was reviewed for flow diversion of the MCA and antiplatelet therapy.Resulting from the special anatomical characteristics of the MCA, FDS implantation in this territory is completely different from the proximal vessel segments. Still, flow diversion represents an effective endovascular strategy, especially in otherwise non-accessible or sufficiently treatable lesions. However, the risk of ischemic adverse events might be increased. Special attention to the individual decision regarding device selection, antiplatelet regimen, and exact definition of the proximal and distal landing zone considering the jailed side branches is essential for a good angiographic and clinical outcome. · MCA aneurysms can be sufficiently treated by FDS.. · The anatomic and hemodynamic characteristics of the MCA result in an increased risk of thromboembolism.. · Individual device selection and antiplatelet regimen are essential for treatment success.. · Schüngel M, Wohlgemuth WA, Elolf E et al. Review: Flow Diversion for the Treatment of Middle Cerebral Artery Aneurysms. Rofo 2025; DOI 10.1055/a-2343-0046.

Safety and Efficacy of Thrombectomy for Distal Medium Vessel Occlusions of the Middle Cerebral Artery

PURPOSE

Mechanical thrombectomy (MT) for distal medium vessel occlusions (DMVOs) in the middle cerebral artery (MCA) is less established than for large vessel occlusions. This study evaluates the safety and efficacy of MT in DMVOs, comparing it with M1-segment occlusions.

MATERIALS AND METHODS

This retrospective study analyzed 218 patients who underwent MT for isolated M1 (n=123) or distal M2+M3 (n=35) occlusions between January 2020 and August 2023. Outcomes included procedural complications, hemorrhagic events, reperfusion rates, and clinical severity and disability at admission and discharge. Multivariate logistic regression identified predictors of favorable outcomes (modified Rankin Scale≤2) at discharge.

RESULTS

Median admission National Institutes of Health Stroke Scale (NIHSS) scores were higher in the M1 group (13, interquartile range [IQR]: 8) compared to the distal M2+M3 group (8, IQR: 7; P<0.001), with significant improvements at discharge in both groups (6 [IQR: 8] for M1 and 2.5 [IQR: 5] for M2+M3; P=0.025). Favorable outcomes were more frequent in the M2+M3 group (50.0%) compared to M1 (28.1%; P=0.023). Recanalization rates (modified Thrombolysis in Cerebral Infarction≥2b) were excellent (>90% in both groups; P=0.300). Procedural complications were rare, with vessel perforations occurring infrequently (M1: 1.6%; M2+M3: 2.9%; P=0.531). Symptomatic intracranial hemorrhage rates were similarly low (2.4% vs. 2.9%; P=0.889). Multivariate analysis identified younger age (P=0.045) and lower NIHSS (P=0.061) as predictors of favorable outcomes in distal occlusions.

CONCLUSION

MT is safe and effective for DMVOs of the MCA, demonstrating significant improvements in clinical outcomes and comparable complication rates to MT for M1-segment occlusions. Given the typically less severe presentations in DMVO and similar risk profiles, careful patient selection and individualized treatment remain critical.

Trevo 3 Mm and/or AXS Catalyst 5 for the Treatment of Medium Distal Vessel Occlusion Stroke-results from the ASSIST Registry

BACKGROUND

The effect of endovascular therapy (EVT) on the outcome of stroke patients with a medium distal vessel occlusion (MDVO) is unclear. We report the results of MDVO patients treated with the 3 mm Trevo stent retriever (SR) and/or the AXS Catalyst 5 distal access catheter.

METHODS

Data was derived from a prospective, multicenter global registry (ASSIST registry) which enrolled patients treated with operator preferred EVT technique at 71 sites from January 2019 to January 2022. Three techniques were assessed: SR classic, direct aspiration, and a combined approach. Additional inclusion criteria were (a) EVT performed with the 3 mm Trevo SR and/or AXS Catalyst 5 distal access catheter on the first pass and (b) an occlusion of the M2 segment or M3 segment of the middle cerebral artery or the A1, A2 or A3 segment of the anterior cerebral artery. The primary outcome was achieving an expanded Thrombolysis in Cerebral Infarction (eTICI) score of 2c or 3 on the first pass, with the primary technique as adjudicated by core lab. The primary clinical outcome measure was a 90-day modified Rankin Scale (mRS) score of 0-2.

RESULTS

A total of 155 patients (10.4% of the ASSIST population) were included. Most patients had an M2 occlusion (93.5%). First pass eTICI reperfusion was achieved in 43.1% of the patients. No modifying effect of the frontline technique was found. The rate of mRS 0-2 (overall 65.0%) did not significantly differ between groups.

CONCLUSION

The data suggests that the Trevo 3 mm SR and/or the AXS Catalyst 5 may be an option to treat medium distal vessel occlusion, but more data is needed to demonstrate safety and efficacy in this patient cohort. Further improvements are needed regarding materials and techniques to improve reperfusion results in this patient cohort in the future.

High Hypoperfusion Intensity Ratio Is Independently Associated with Very Poor Outcomes in Large Ischemic Core Stroke

BACKGROUND

Recent advances have highlighted the efficacy of endovascular thrombectomy (EVT) in patients with large ischemic core stroke, yet a significant portion still experience very poor outcomes, defined as a 90-day modified Rankin Score (mRS) of 5-6. This study aims to investigate the hypoperfusion intensity ratio (HIR) as a prognostic imaging parameter for these outcomes.

METHODS

In a multicenter retrospective cohort study, data from consecutive patients undergoing EVT for acute ischemic stroke with large vessel occlusion (AIS-LVO) at two comprehensive stroke centers were analyzed. The study included patients with an Alberta Stroke Program Early CT Score (ASPECTS) of 5 or less and utilized pretreatment perfusion imaging to calculate HIR. The primary outcome was very poor outcomes (90 days mRS 5-6).

RESULTS

Among 102 patients included, 59 (57.8%) had very poor outcome (90 days mRS 5-6). Multivariable logistic regression analysis adjusting for multiple covariates including admission National Institutes of Health Stroke Scale (NIHSS) and EVT revealed that higher admission NIHSS (adjusted odds ratio [aOR] 1.224, 95% CI 1.089-1.374, p = 0.001) and HIR (aOR per 0.1 incremental change, 1.34, 95% CI 1.02-1.82, P = 0.042) were independently associated with very poor outcomes.

CONCLUSION

This study demonstrates that admission NIHSS and HIR are independently associated with very poor outcome (90 days mRS 5-6) in patients with large ischemic core strokes. These findings highlight the importance of collateral status and perfusion imaging in predicting outcomes in this patient population, suggesting a potential role for HIR in the triage and management of large core stroke patients.

Factors Influencing the Association of 24-hour National Institutes of Health Stroke Scale & 90-day Modified Rankin Score

PURPOSE

The modified Rankin Scale (mRS) at 90 days is the primary outcome in most acute stroke studies, but the long follow-up period has disadvantages. The National Institutes of Health Stroke Scale (NIHSS) at 24 h shows a strong, but imperfect, association with 90-day mRS. This study examines the association between 24-hour NIHSS and 90-day mRS and reasons for discrepancies.

METHODS

Data are from the ESCAPE-NA1 thrombectomy patients. To address the non-normality distribution of the NIHSS and include deceased patients, a 7-point ordinal score was generated by grouping 24-hour NIHSS. The association of ordinal 24-hour NIHSS and 90-day mRS was assessed with adjusted ordinal logistic regression. Differences in baseline and treatment/post-treatment variables were compared between patients with discordant and concordant outcomes.

RESULTS

One-thousand-seventy-six patients with available 24-hour NIHSS and 90-day mRS were included (median 24-hour NIHSS 6[IQR: 2-14], median 90-day mRS 2[IQR: 1-4]). Ordinal 24-hour NIHSS was associated with 90-day mRS (adjusted cOR 2.53 [95%CI 2.33-2.74]). Forty-eight (4.5%) patients had discordant outcomes. Of those, 19(1.8%) had 24-hour NIHSS < 6 and 90-day mRS5-6; all of which had ≥ 1 severe adverse event, most commonly pneumonia (6[31.6%]) or recurrent stroke (4[21.1%]). Twenty-nine patients (2.7%) had 24-hour NIHSS > 14 and 90-day mRS 0-2. In these patients, baseline NIHSS and ASPECTS was lower, and collateral status was worse.

CONCLUSION

An ordinal NIHSS score that includes death at 24 h shows a strong association with 90-day mRS, suggesting that it could be used as an alternative outcome. Patients with discrepant outcomes differed from the remaining patients regarding their baseline NIHSS, ASPECTS, collateral status, and post-stroke complications.

Predictors of poor outcome in acute stroke patients with posterior cerebral artery occlusion and medical management

BACKGROUND AND AIMS

The clinical evolution of acute ischemic stroke patients with isolated proximal posterior cerebral artery (PCA) occlusion treated with medical management alone has been poorly described. We aimed to determine the clinical and radiological factors associated with poor functional outcome in this population.

METHODS

We conducted a multicenter international retrospective study of consecutive stroke patients with isolated occlusion of the first (P1) or second (P2) segment of PCA admitted within 6 h from symptoms onset in 26 stroke centers in France, Switzerland, and the United States, treated with the best medical management alone. Poor functional outcome was defined as a modified Rankin scale (mRS) ⩾2 at 3 months or no return to pre-stroke mRS. The associations between pretreatment variables and poor outcome were studied in univariable and then multivariable analyses, as well as the association between poor outcome and key follow-up radiological variables.

RESULTS

Overall, 585 patients were included. The median age was 74 years (interquartile range (IQR) = 63-83), median National Institutes of Health Stroke Scale (NIHSS) was 6 (3-10), 80% received intravenous thrombolysis (IVT), and 22% and 78% had P1 and P2 occlusions, respectively. Poor outcome occurred in 56% of patients. In multivariable analysis focusing on pretreatment variables, age (adjusted odds ratio (OR) = 1.12 per 5-year increase [95% confidence interval (CI) = 1.05-1.20]; p = 0.001), NIHSS score (aOR = 1.12 per each point increase [1.08-1.18]; p < 0.001), infarct volume (aOR = 1.16 per 5 mL increase [1.07-1.25]; p < 0.001), and the lack of IVT use (aOR = 1.79 [1.10-2.94], p = 0.020) were independently associated with poor outcome. Regarding 24-h follow-up radiological variables, complete recanalization (defined as no clot in the vascular tree at or beyond the primary occlusive lesion, aOR = 0.37 [95% CI = 0.21-0.65], p < 0.001) and parenchymal hematoma occurrence (aOR = 2.37 [95% CI = 1.01-5.56], p = 0.048) were independently associated with poor 3-month outcome.

CONCLUSIONS

Poor outcome occurred in more than half of medically treated PCA-related acute stroke patients. Facilitating IVT use may improve functional outcome. Therapeutic approaches aimed at enhancing recanalization and reducing hemorrhagic transformation need to be studied in clinical trials.

A visual journey through medium vessel occlusion strokes: From diagnosis to treatment

Acute ischemic stroke occurs when a blood clot obstructs cerebral blood flow, leading to ischemia and potentially irreversible brain damage. While large vessel occlusions are known for their catastrophic effects, medium vessel occlusions (MeVOs) also contribute significantly to stroke-related disability. These occlusions, which occur in smaller, mid-sized vessels, can result in substantial neurological deficits depending on their location and the availability of collateral circulation. The detection of MeVOs poses unique diagnostic challenges, as their subtle presentations are often overlooked in standard imaging. Timely and accurate identification is critical for initiating appropriate therapies, including intravenous thrombolysis, endovascular thrombectomy, and secondary prevention measures. This editorial takes you on a visual journey through the world of MeVOs, exploring their locations, challenging cases, and the diverse techniques used to identify them. With detailed illustrations, it demonstrates how to recognize these occlusions on both advanced and conventional imaging, including guidance on spotting them on digital subtraction angiography. Finally, it delves into how these strokes are treated, offering a comprehensive and engaging look at the unique challenges and solutions in MeVO management.

Mechanical Thrombectomy for Middle Cerebral Artery Medium Vessel Occlusions Using Single Plane Angiography

BACKGROUND AND PURPOSE

Endovascular thrombectomy is now the standard of care for large vessel occlusion acute ischemic stroke. However, acute stroke due to medium-vessel occlusions often result in unfavorable outcomes, and guidelines for thrombectomy are lacking. Moreover, nearly all clinical data and thrombectomy trials are based on biplane angiography systems. This study aims to compare the safety and efficacy of stroke thrombectomy procedures performed on single-plane versus biplane angiography systems in patients presenting with medium-vessel occlusions of the middle cerebral artery.

MATERIALS AND METHODS

This retrospective study included consecutive patients with acute ischemic stroke due to primary middle cerebral artery medium-vessel occlusions treated with thrombectomy between 7/1/2020 and 8/1/2022 at a single high-volume practice. Patients were dichotomized into those treated on single plane and biplane systems. Demographic, procedural, clinical and follow-up characteristics were compared.

RESULTS

Among the 149 patients included, 44 underwent thrombectomy on single-plane systems, and 93 on biplane systems. No significant differences were detected in rates of good functional outcomes (mRS < 2; SP 54% vs BP 42%, p = 0.19), successful recanalization (TICI ≥ 2B; SP 91% vs BP 86%, p = 0.77), intra-procedural vascular injury (SP 0% vs BP 3%; p = 0.56), or time from groin puncture to reperfusion (SP 25 min vs BP 27 min; p = 0.97). No significant differences were detected in peri-procedural complications, or symptomatic intracerebral hemorrhage.

CONCLUSION

Thrombectomy for middle cerebral artery medium-vessel occlusions performed on single-plane angiography systems is as safe and efficacious as biplane procedures. Our results may have implications for increasing access to care, especially in regions with limited resources.

Inter-proceduralist variability in angiographic outcomes after stroke thrombectomy and the importance of quality over quantity of passes

BACKGROUND

Complete recanalization (CR, modified Treatment in Cerebral Ischemia (mTICI) score of 2c or better) is associated with favorable outcomes after endovascular thrombectomy (EVT) for stroke patients. However, the degree of inter-proceduralist differences in CR rates is unknown, and whether higher CR rates are being achieved by performing more passes or by focusing on first-pass effectiveness is also unclear.

METHODS

This was a multicenter retrospective study of anterior circulation large vessel occlusion stroke patients in the United States from 2016 to 2022. Patients treated by proceduralists with at least 50 cases were included. CR rates for each proceduralist were assessed and proceduralists were divided into tertiles. First-pass effect (FPE, defined as CR after one pass) and the number of passes for patients treated by the top tertile of proceduralists were compared with the bottom tertile. Mediation analyses were conducted to assess causal links between CR rates and number of passes or FPE.

RESULTS

A total of 1096 EVTs performed by 11 proceduralists were identified. CR rates were highly variable across providers (43.1% to 75.3%, p<0.001). Patients treated by the top tertile were more likely to experience FPE (OR 1.99, 95% CI 1.49 to 2.67, p<0.001) and did not undergo more passes (p=0.69) compared with the bottom tertile. Higher rates of FPE among patients was a significant mediator of higher odds of CR among patients treated by the top tertile (p<0.001).

CONCLUSIONS

Angiographic outcomes among EVT proceduralists are highly variable. Proceduralists who achieve higher rates of CR are doing so with higher rates of FPE, not more passes.

Endovascular Treatment of Stroke Due to Medium-Vessel Occlusion

BACKGROUND

Whether the large effect size of endovascular thrombectomy (EVT) for stroke due to large-vessel occlusion applies to stroke due to medium-vessel occlusion is unclear.

METHODS

In a multicenter, prospective, randomized, open-label trial with blinded outcome evaluation, we assigned patients with acute ischemic stroke due to medium-vessel occlusion who presented within 12 hours from the time that they were last known to be well and who had favorable baseline noninvasive brain imaging to receive EVT plus usual care or usual care alone. The primary outcome was the modified Rankin scale score (range, 0 [no symptoms] to 6 [death]) at 90 days, reported as the percentage of patients with a score of 0 or 1.

RESULTS

A total of 530 patients from five countries were enrolled between April 2022 and June 2024, with 255 patients assigned to the EVT group and 275 to the usual-care group. Most patients (84.7%) had primary occlusions in a middle-cerebral-artery branch. A modified Rankin scale score of 0 or 1 at 90 days occurred in 106 of 255 patients (41.6%) in the EVT group and in 118 of 274 (43.1%) in the usual-care group (adjusted rate ratio, 0.95; 95% confidence interval [CI], 0.79 to 1.15; P = 0.61). Mortality at 90 days was 13.3% in the EVT group and 8.4% in the usual-care group (adjusted hazard ratio, 1.82; 95% CI, 1.06 to 3.12). Symptomatic intracranial hemorrhage occurred in 14 of 257 patients (5.4%) in the EVT group and in 6 of 272 (2.2%) in the usual-care group.

CONCLUSIONS

Endovascular treatment for acute ischemic stroke due to medium-vessel occlusion within 12 hours did not lead to better outcomes at 90 days than usual care. (Funded by the Canadian Institutes for Health Research and Medtronic; ESCAPE-MeVO ClinicalTrials.gov number, NCT05151172.).

Mechanical thrombectomy failure in anterior and posterior circulation stroke: current results from a high-volume comprehensive center

BACKGROUND

Mechanical thrombectomy (MT) is an established therapy for acute ischemic stroke (AIS), but recanalization is not always achieved. Common reasons are inadequate removal at the thrombus site and difficulties with the access route. In order to identify risk factors for MT failure we conducted a retrospective study on a high-volume comprehensive stroke center.

METHODS

Evaluation of 552 thrombectomies (2019-23; anterior and posterior circulation, direct aspiration +/- stent retriever [SR]). MT failures (= modified Thrombolysis in Cerebral Infarction score 0 or 1) were analyzed for age, sex, pre- and post-MT modified Rankin Scale, bridging intravenous thrombolysis (IVT), occlusion site (anterior / posterior circulation, proximal / distal), the Kaesmacher classification and time trend results.

RESULTS

MT failure occurred in 56 patients (10.1%; median age 76; 53.6% female). Nineteen (33.9%) patients received IVT (p = 0.326). Logistic regression analysis did not show a significant association of age, sex or occlusion site with MT failure (p = 0.165, p = 0.738, p = 0.838). Distal MT generally demonstrated lower success rates (p < 0.01). According to the Kaesmacher classification SR failure was the most frequent cause of MT failure (category 2B: 48%, p < 0.001). Time trend analysis suggests improving recanalization rates in the further course (4 times in year-on-year comparison; p < 0.01).

CONCLUSION

MT failure occurs in AIS treatment, even in high-volume centers and occurs more frequently in distal occlusions. Improvements in device technology, particularly SR, and ongoing refinements in access route selection offer the prospect of better outcomes in the future.

Advances in the Critical Care of Ischemic Brain Infarction

Acute care for ischemic stroke has dramatically evolved over the last years. Cerebral reperfusion is possible up to 24 h after symptoms onset. Advanced brain imaging allows identifying salvageable ischemic brain tissue, and the development of newer endovascular devices permits access to distal vessels. Monitoring for neurologic deterioration, diagnosis of stroke etiology, and secondary prevention treatments are important after initial treatment. This article reviews the recent advancements in the critical care of acute ischemic stroke.

[Endovascular thrombectomy of medium vessel occlusions]

BACKGROUND

Acute ischemic stroke is a leading cause of disability and dependency in daily life. While endovascular therapy has become the standard treatment for large vessel occlusions, its benefit for medium vessel occlusions has not yet been clearly established.

OBJECTIVE

This article provides an overview of the current evidence, epidemiology, and clinical challenges of thrombectomy in distal medium vessel occlusions (DMVOs).

Endovascular therapy versus medical management in isolated anterior cerebral artery acute ischemic stroke: a multinational multicenter propensity score-weighted study

BACKGROUND

Isolated anterior cerebral artery occlusions (ACAo) in patients with acute ischemic stroke present significant challenges due to their rarity. The efficacy and safety of endovascular therapy (EVT) in comparison with best medical therapy (BMT) for ACAo remains unclear. This study aimed to assess the outcomes of these treatments.

METHODS

This multinational, multicenter study analyzed data from the MAD-MT registry. Data were collected retrospectively from 37 sites across North America, Asia, and Europe. Inverse probability of treatment weighting (IPTW) was applied to balance confounding variables. The primary outcome was functional independence (modified Rankin Scale (mRS) scores of 0-2) at 90 days. Secondary outcomes included excellent outcomes (mRS 0-1), mortality at 90 days, and NIH Stroke Scale (NIHSS) score on day 1 post treatment.

RESULTS

Of the 108 patients, 36 received BMT and 72 underwent EVT. The median age was 75 years, and 56% were male. At 90 days, 40% of patients achieved mRS 0-2, with no significant difference between EVT and BMT (38% vs 45%, p=0.46). Procedural success (mTICI 2b-3) was 91% in the EVT group, with a sICH rate of 2.9%. IPTW-adjusted analysis showed no significant difference between EVT and BMT for functional independence (OR 1.17, 95% CI 0.23 to 6.02, p=0.85), mortality (25% vs 21%, p=0.71) or day 1 NIHSS scores (Beta 2.2, 95% CI -0.51 to 4.8, p=0.11).

CONCLUSIONS

EVT showed high procedural success but did not significantly improve functional outcomes or mortality compared with BMT in patients with ACAo. Further randomized trials are needed to clarify EVT's role in ACAo.

DOT sign indicates persistent hypoperfusion and poor outcome in patients with incomplete reperfusion following thrombectomy

BACKGROUND

Distal occlusions associated with incomplete reperfusion (expanded Thrombolysis in Cerebral Infarction,

METHODS

Retrospective registry analysis of patients undergoing endovascular therapy between July 2020 and December 2022, with available immediate post-interventional FPDCT and 24 hours follow-up perfusion imaging. Persistent hypoperfusion was defined as a perfusion deficit at 24 hours directly corresponding to the area of incomplete reperfusion on final angiography run. The DOT sign was defined as a punctiform or tubular hyperdense signal increase on FPDCT indicative of a residual occlusion. Association between the DOT sign (present/absent) with the occurrence of persistent hypoperfusion and poor outcome (modified Rankin scale (mRS) score 3-6) was evaluated using logistic regression analysis.

RESULTS

Of 292 patients included (median age 73 years; 47% female), 209 had incomplete reperfusion. Among patients with incomplete reperfusion, 61% had a present DOT sign and 46% had persistent hypoperfusion. In the overall cohort, but also within each eTICI stratum, a present DOT sign was associated with persistent hypoperfusion on 24±12 hours follow-up perfusion imaging (adjusted odds ratio (aOR) 4.8, 95% confidence interval (CI) 2.0 to 12.3 for patients with eTICI 2 a-2c). A present DOT sign was also associated with poor outcome (aOR 2.6, 95% CI 1.1 to 6.2).

CONCLUSION

Patients with Collapse

Key Words

• CT Angiography
• Intervention
• MR perfusion
• Stroke
• Thrombectomy

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MESH Headings Collapse

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Affiliation(s)

Adnan Mujanovic Department of Diagnostic and Interventional Neuroradiology, University Hospital Bern Inselspital, Bern, Switzerland Graduate School for Health Sciences, University of Bern, Bern, Switzerland
Daniel Windecker Department of Diagnostic and Interventional Neuroradiology, University Hospital Bern Inselspital, Bern, Switzerland
Bettina Serrallach Department of Diagnostic and Interventional Neuroradiology, University Hospital Bern Inselspital, Bern, Switzerland
Christoph C Kurmann Department of Diagnostic and Interventional Neuroradiology, University Hospital Bern Inselspital, Bern, Switzerland Graduate School for Health Sciences, University of Bern, Bern, Switzerland Department of Diagnostic, Interventional and Pediatric Radiology, University Hospital Bern Inselspital, Bern, Switzerland
Roman Rohner Department of Diagnostic and Interventional Neuroradiology, University Hospital Bern Inselspital, Bern, Switzerland Graduate School for Health Sciences, University of Bern, Bern, Switzerland
Elias Auer Department of Neurology, Inselspital University Hospital Bern, Bern, Switzerland
Petra Cimflova Department of Diagnostic and Interventional Neuroradiology, University Hospital Bern Inselspital, Bern, Switzerland Department of Neuroradiology, University Hospital Freiburg, Freiburg, Germany Department of Medical Imaging, St. Anne's University Hospital Brno, Brno, Czech Republic
Thomas R Meinel Department of Neurology, Inselspital University Hospital Bern, Bern, Switzerland
Franziska Dorn Department of Neuroradiology, University Hospital Bonn, Bonn, Germany
René Chapot Department of Neuroradiology and Endovascular Therapy, Alfried Krupp Krankenhaus Ruttenscheid, Essen, Germany
David Seiffge Department of Neurology, Inselspital University Hospital Bern, Bern, Switzerland
Eike Immo I Piechowiak Department of Diagnostic and Interventional Neuroradiology, University Hospital Bern Inselspital, Bern, Switzerland
Tomas Dobrocky Department of Diagnostic and Interventional Neuroradiology, University Hospital Bern Inselspital, Bern, Switzerland
Jan Gralla Department of Diagnostic and Interventional Neuroradiology, University Hospital Bern Inselspital, Bern, Switzerland
Urs Fischer Department of Neurology, Inselspital University Hospital Bern, Bern, Switzerland
Sara Pilgram-Pastor Department of Diagnostic and Interventional Neuroradiology, University Hospital Bern Inselspital, Bern, Switzerland
Johannes Kaesmacher Department of Diagnostic and Interventional Neuroradiology, University Hospital Bern Inselspital, Bern, Switzerland Diagnostic and Interventional Neuroradiology, CIC-IT 1415, CHRU de Tours, Tours, France Le Studium Loire Valley Institute for Advanced Studies, Orléans, France

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Efficacy and safety outcomes of endovascular versus best medical treatment in posterior cerebral artery occlusion stroke

BACKGROUND

The management of acute ischemic stroke due to isolated posterior cerebral artery occlusion (iPCAO) remains a topic of debate. This study investigates the efficacy and safety of endovascular treatment (EVT) versus best medical treatment (BMT) in patients with iPCAO.

METHODS

A systematic search was conducted across electronic databases including PubMed, Embase, and the Cochrane Library. Controlled studies comparing EVT and BMT in patients with iPCAO were selected. The primary efficacy outcome assessed was excellent outcome, defined as a modified Rankin Scale (mRS) score of 0-1. The primary safety outcome was symptomatic intracranial hemorrhage (sICH). Secondary outcomes included functional independence (mRS 0-2), early neurological improvement (ENI), and mortality rates. Statistical analyses were conducted using random effects models.

RESULTS

Eleven retrospective cohort studies involving 1811 patients with EVT and 2871 patients with BMT were analyzed. Compared with BMT, EVT was associated with a higher likelihood of an excellent outcome (adjusted OR (aOR) 1.33, 95% CI 1.14 to 1.54) and ENI (aOR 1.66, 95% CI 1.39 to 1.98), but no significant difference in functional independence (aOR 1.02, 95% CI 0.88 to 1.18). Compared with BMT, EVT may not be associated with an increased risk of sICH in patients with iPCAO (aOR 1.34, 95% CI 0.60 to 3.02) or mortality (aOR 1.31, 95% CI 0.83 to 2.08), although heterogeneity was high.

CONCLUSIONS

EVT may improve the likelihood of an excellent outcome and ENI in patients with iPCAO. However, the potential risks of sICH and mortality warrant consideration. Randomized trials are required to establish the definitive efficacy and safety of EVT in this patient population.

Intracranial thrombus composition is associated with occlusion location and endovascular treatment outcomes: results from ITACAT multicenter study

BACKGROUND

The impact of thrombolytics directed towards different thrombus components regarding site of occlusion in combination with mechanical thrombectomy (MT) to achieve endovascular complete recanalization is unclear.

METHODS

Retrospective analysis of a prospective database in two stroke centers. Intracranial thrombi retrieved by MT were analyzed using hematoxylin-eosin staining for fibrin and red blood cell proportions, and CD61 immunostaining for platelets proportion in thrombus (PLTPT) assessment. Thrombi composition, baseline variables, etiology, treatment features and occlusion location were analyzed.

RESULTS

Overall, 221 patients completed the per protocol analysis and 110 cases achieved a final expanded Thrombolysis in Cerebral Infarction (eTICI) 3 (49%) of which 70 were MT (32%) by first pass effect (FPE). Thrombi from medium distal vessel occlusions had higher PLTPT compared with thrombi from proximal large vessel occlusions (68% vs 61%, P=0.026). In particular, middle cerebral artery M2-M3 segment thrombi had the highest PLTPT (70%), and basilar artery thrombi the lowest PLTPT (41%). After logistic regression analysis adjusted for occlusion location and intravenous fibrinolysis, lower baseline National Institutes of Health Stroke Scale score (adjusted OR (aOR) 0.95, 95% CI 0.913 to 0.998) and PLTPT (aOR 0.97, 95% CI 0.963 to 0.993) were independently associated with FPE. Fewer MT passes (aOR 0.67, 95% CI 0.538 to 0.842) and platelet poor thrombus (<62% PLTPT; aOR 2.39, 95% CI 1.288 to 4.440) were independently associated with final eTICI 3.

CONCLUSIONS

Occlusion location might be a surrogate parameter for thrombus composition. Platelet poor clots and fewer MT passes were independently associated with complete endovascular recanalization. Clinical trials testing the benefits of combining selective intra-arterial platelet antagonists with MT to improve endovascular outcomes are warranted.

Tenzing Assisted Delivery of Aspiration (TADA) technique for thrombectomy of medium vessel occlusions using the Freeclimb 54 catheter: multicenter experience

BACKGROUND

Medium vessel occlusions (MeVOs) account for 25-40% of acute ischemic stroke. The Tenzing 5 (Route 92 Medical, San Mateo, California, USA) and FreeClimb 54 (Route 92 Medical, San Mateo, California, USA) catheter is a novel delivery-aspiration catheter combination designed to facilitate aspiration thrombectomy (AT) of MeVOs. We report our clinical experience using the Tenzing assisted delivery of aspiration (TADA) technique with FreeClimb 54 for first-line AT of MeVO.

METHODS

We retrospectively reviewed consecutive patients who underwent MeVO first-line AT using TADA with FreeClimb 54 at nine institutions in the USA and one in New Zealand.

RESULTS

94 MeVOs (65 primary, 29 secondary) were treated in 92 patients: median age 71 (IQR 58-81) years; 49/92 (53%) women. FreeClimb 54 was successfully delivered by Tenzing 5 to all 94/94 MeVOs: 26 proximal M2; 44 distal M2; 5 M3; 6 A2; 4 A3; and 8 P2. Median target vessel diameter on DSA was 1.7 (IQR 1.4-1.8) mm. A leading microwire was used to advance Tenzing in 84% of cases. A stent retriever was used for additional thrombectomy passes in 6/94 (6%) patients. For a primary MeVO, final modified expanded Thrombolysis in Cerebral Infarction (meTICI) 2B-3 reperfusion was achieved in 63/65 (97%) patients, after a median of 1 (IQR 1-2) pass, with a first pass effect (FPE, meTICI 2C-3) in 43/65 (66%). Secondary MeVO FPE (eTICI 2C-3) was achieved in 20/29 (69%) patients. Tenzing 5-FreeClimb 54 related complications occurred in 2/94 (2%) patients: one perforation with asymptomatic subarachnoid hemorrhage and one embolus to new territory.

CONCLUSIONS

MeVO first-line AT using the TADA technique with Tenzing 5 and FreeClimb 54 had a high FPE with a low complication rate.

Numerical Cincinnati Stroke Scale Versus Stroke Severity Screening Tools for the Prehospital Determination of Large Vessel Occlusion

OBJECTIVES

Previous research demonstrated that the numerical Cincinnati Prehospital Stroke Scale (CPSS) identifies large vessel occlusion (LVO) at similar rates compared to dedicated LVO screening tools. We aimed to compare numerical CPSS to additional stroke scales using a national emergency medical services (EMS) database.

METHODS

Using the ESO Data Collaborative, the largest EMS database with linked hospital data, we retrospectively analyzed prehospital patient records from 2022. Each EMS record was linked to corresponding emergency department (ED) and inpatient records through a data exchange platform. Prehospital CPSS was compared to the Cincinnati Stroke Triage Assessment Tool (C-STAT), the Field Assessment Stroke Triage for Emergency Destination (FAST-ED), and the Balance Eyes Face Arm Speech Time (BE-FAST). The optimal prediction cut points for LVO screening were determined by intersecting the sensitivity and specificity curves for each scale. To compare the discriminative abilities of each scale among those diagnosed with LVO, we used the area under the receiver operating curve (AUROC).

RESULTS

We identified 17,442 prehospital records from 754 EMS agencies with ≥1 documented stroke scale of interest: 30.3% (n = 5,278) had a hospital diagnosis of stroke, of which 71.6% (n = 3,781) were ischemic; of those, 21.6% (n = 817) were diagnosed with LVO. CPSS score ≥2 was found to be predictive of LVO with 76.9% sensitivity, 68.0% specificity, and AUROC 0.787 (95%CI 0.722-0.801). All other tools had similar predictive abilities, with sensitivity/specificity/AUROC of: C-STAT 62.5%/76.5%/0.727 (0.555-0.899); FAST-ED 61.4%/76.1%/0.780 (0.725-0.836); BE-FAST 70.4%/67.1%/0.739 (0.697-0.788).

CONCLUSIONS

The less complex CPSS exhibited comparable performance to three frequently employed LVO detection tools. The EMS leadership, medical directors, and stroke system directors should weigh the complexity of stroke severity instruments and the challenges of ensuring consistent and accurate use when choosing which tool to implement. The straightforward and widely adopted CPSS may improve compliance while maintaining accuracy in LVO detection.

Successful Mechanical Thrombectomy for Bilateral Anterior Cerebral Artery Occlusions in a Rare Anatomical Variant: A Case Report

Background

Acute ischemic stroke (AIS) is usually caused by acute occlusion of the cerebral artery. Bilateral anterior cerebral arteries (ACAs) originating from the anterior communicating branch of the same internal carotid artery are a rare anatomical variation in clinical practice. Mechanical thrombectomy (MT) of simultaneous acute occlusion of the bilateral ACAs with this variation has rarely been reported.

Case Presentation

A 49-year-old man was referred for sudden onset of right-side weakness and aphasia for almost 55 min. AIS was considered after no bleeding was observed on emergency head computed tomography. Digital subtraction angiography was performed, and bilateral ACAs were found to originate from the anterior communicating branch of the left internal carotid artery and were occluded in their A2 segment. After immediate emergency MT with a stent retriever, the symptoms obviously improved.

Conclusion

Simultaneous acute occlusion of the bilateral ACAs originating from the anterior communicating branch of the same internal carotid artery is rare in clinical practice. For such patients, MT with a stent retriever is feasible even if there is a risk of thrombectomy escape, and a stent retriever with aspiration or a direct aspiration technique may be more appropriate.

Medium vessel occlusions in the drip-and-ship model: Clinical vs. hub CTP-supported decision making

INTRODUCTION

Mechanical thrombectomy (MT) for medium vessel occlusions (MeVO) is emerging as a promising treatment in acute stroke. We aim to evaluate the utility of additional imaging (CTP) in patients with MeVOs who received thrombolysis at a spoke hospital and were transferred to the hub.

METHODS

This was a retrospective review of prospectively collected data from April 2018 to June 2023. Patients were transferred to one of the following destinations: CT scanner for a perfusion scan, directly to the angiography suite, or admitted to the neurological intensive care unit (NICU). We compared baseline characteristics, MT times, radiographic and clinical outcomes between the group that was initially transferred to CTP vs. the group that was not initially transferred to CTP.

RESULTS

Seventy-eight MeVO patients who received IV thrombolysis and were transferred to our comprehensive stroke center were included in the analysis. Forty patients went directly to CTP, thirty went directly to the angiography suite (DTA), and eight were transferred to the NICU. 67.5% of patients presenting to CTP did not subsequently go to the angiography suite. The CTP and non-CTP groups did not differ significantly in terms of demographics, rates of successful recanalization, complications, and clinical outcomes at 90 days. The CTP group had significantly longer median door-to-groin times and median door-to-recanalization times.

CONCLUSION

Mechanical thrombectomy should be considered in stroke patients with confirmed medium vessel occlusions who receive thrombolysis. CTP utilization may lead to lower angiography utilization and longer door-to-procedure times but does not significantly affect long-term outcomes.

Rescue therapy after failed thrombectomy in medium/distal vessel occlusions: A retrospective analysis of an international, multi-center registry

BACKGROUND

There are limited therapeutic options in cases of failed reperfusion (modified thrombolysis in cerebral infarction [mTICI] score < 2b) after stent-retriever and/or aspiration based endovascular treatment (EVT) for acute ischemic stroke. Despite the absence of data supporting its use, rescue therapy (balloon angioplasty and/or stent implantation) is often utilized in such cases. Studies are limited to large vessel occlusions, while the outcomes and complications after rescue therapy in medium/distal vessel occlusions (MDVOs) have not been reported. This study aims to report the outcomes of rescue therapy in MDVO stroke patients.

METHODS

We performed an analysis of the "Blood pressure and Antiplatelet medication management after reScue angioplasty after failed Endovascular treatment in Large and distal vessel occlusions with probable IntraCranial Atherosclerotic Disease" (BASEL ICAD) retrospective registry. All MDVO stroke patients were included in the analysis.

RESULTS

Out of the 718 registry patients, 87 (12.1%) presented with an MDVO. Fifty-six patients (64.4%) showed an occlusion of the M2 segment of the middle cerebral artery. Rescue stenting was performed in 78 patients (89.7%) while balloon angioplasty alone was performed in 9 patients (10.3%). Successful reperfusion (mTICI score ⩾ 2b) was achieved in 73 (83.9%) patients after rescue therapy. Symptomatic intracranial hemorrhage (sICH) occurred in 8 patients (9.2%) and post-treatment stent occlusion in 12 patients (13.8%). Ninety days mortality was 20.7%. Twenty-eight patients (32.2%) achieved functional independence at 90 days (modified Rankin Scale 0-2).

CONCLUSION

Rescue therapy with stenting and/or balloon angioplasty in patients undergoing EVT for isolated MDVO with suspected underlying intracranial atherosclerotic disease is an effective reperfusion strategy but is associated with complications and poor functional outcomes.

Introduction and accuracy assessment of Nicolab's StrokeViewer in a developing stroke thrombectomy UK service. a service development/improvement project

AIM

The aim of this study was to evaluate the implementation of artificial intelligence (AI) software in a quaternary stroke centre as well as assess the accuracy and efficacy of StrokeViewer software in large vessel occlusion detection and its potential impact on radiological workflow.

MATERIALS AND METHODS

Data were collected during two separate three-month periods comparing the accuracy rate of StrokeViewer in detection of large vessel occlusion to that of a junior registrar. During the first three months, 37 cases were identified and during the second leg, 47. The second leg of the study was performed due to a high number of technical failures during the first one and in an attempt to improve those via communication with the manufacturer and co-operation between allied healthcare professionals. Statistical analysis was performed using SPSS software.

RESULTS

Technical failure rate was 25% in the first leg and reduced to 17% in the second leg, showing a trend to statistical significance. Specificity and sensitivity of StrokeViewer were similar in the two legs of the study, measuring 91% and 93% initially and 94% and 93% finally, respectively. Efficacy was comparable to that of the junior registrar with StrokeViewer, demonstrating 92% accuracy during the first leg vs 95% by the junior registrar and 93% in the second leg vs 98% by the junior registrar. These did not show statistical significance.

CONCLUSION

This is a real-life analysis of StrokeViewer efficacy and its potential failures, showing a reduction in failure rate, accuracy rate of a junior registrar, and sensitivity and specificity values close to the advertised ones.

Penumbral Imaging to Guide Endovascular Treatment for M2 Middle Cerebral Artery Stroke

BACKGROUND

A potential benefit of mechanical thrombectomy for patients with distal medium vessel occlusions is currently being investigated in randomized trials. Computed tomography perfusion imaging has not yet been tested as a method to guide mechanical thrombectomy for distal medium vessel occlusions. The purpose of this study was to assess penumbral imaging as an imaging-based method for triaging patients with ischemic stroke and acute M2-middle cerebral artery occlusion.

METHODS

This observational retrospective study of M2-middle cerebral artery patients with ischemic stroke triaged by multimodal computed tomography undergoing mechanical thrombectomy at a high-volume stroke center between January 2015 and January 2023. The effect of recanalization was analyzed according to computed tomography perfusion-derived lesion volumes (defined using relative cerebral blood flow <30% and Tmax >6 seconds) using logistic regression analysis, and interaction terms between the independent variables and recanalization were tested. The primary end point was functional independence at day 90, defined using modified Rankin Scale scores of 0 to 2.

RESULTS

A total of 140 patients with M2-middle cerebral artery occlusion were included. In multivariable logistic regression analysis, recanalization was not associated with better functional outcome (adjusted odds ratio, 1.85 [95% CI, 0.87-3.90]; P=0.11). After including interaction terms, a significant treatment effect between recanalization and computed tomography perfusion-derived lesion volumes was observed in patients with >150 mL hypoperfusion volume (adjusted odds ratio, 1.02 [95% CI, 1.00-1.03]; P=0.007) or >125 mL penumbral volumes (adjusted odds ratio, 1.02 [95% CI, 1.01-1.03]; P=0.005), as well as for baseline ischemic core volume within the range of 15 to 40 mL (adjusted odds ratio, 1.11 [95% CI, 1.01-1.22]; P=0.03).

CONCLUSIONS

Penumbral imaging might serve as a useful tool for treatment decision-making in distal medium vessel occlusions, particularly in cases of suspected non- or codominant M2-middle cerebral artery vessel occlusions. A hypoperfusion volume threshold of >150 mL emphasizes the potential value of computed tomography perfusion as a standardized tool directly showing the volumetric relevance in distal medium vessel occlusion cases.

Endovascular thrombectomy for distal medium vessel occlusions: A literature review

BACKGROUND

There is a lack of substantial evidence supporting the safety and effectiveness of endovascular thrombectomy in treating distal medium vessel occlusions (DMVOs).

OBJECTIVE

To summarize the current evidence regarding endovascular thrombectomy for DMVOs.

METHODS

We conducted a narrative review of key articles related to the diagnosis and management of DMVOs. We manually searched PubMed and Google Scholar from January 2010 to July 2023, and only included articles published in the English language.

RESULTS

While diagnosing and treating DMVOs is tricky due to access limitations and potential limited benefit from mechanical clot removal, recent improvements in catheter and retrieval technology suggest that endovascular thrombectomy might be a potential treatment option. However, more high-quality research is needed to confirm its effectiveness for DMVOs.

CONCLUSION

Experts disagree on how to classify DMVOs and what the best mode of endovascular treatment is.

Outcomes of mechanical thrombectomy for medium vessel occlusion in acute ischemic stroke patients with ASPECTS 4-5 vs. 6-7: a retrospective, multicenter, and multinational study

INTRODUCTION

Mechanical thrombectomy (MT) efficacy in medium vessel occlusion (MeVO) stroke, particularly in patients with low Alberta Stroke Program Early Computed Tomography Score (ASPECTS), remains less explored.

METHODS

This retrospective study analyzed data from 443 AIS patients treated with MT for MeVO and low ASPECTS (4-7) at 37 centers across North America, Asia, and Europe, from September 2017 to July 2021. Patients were categorized into ASPECTS of 4-5 and 6-7.

RESULTS

Of 443 patients, 51 (12%) had ASPECTS of 4-5, and 392 (88%) had scores of 6-7. The median age was 65 years (IQR: 46-79), with a balanced sex distribution between the groups. The most common site of initial occlusion was M2 branch in both groups (92% in ASPECTS 4-5 and 85% in ASPECTS 6-7) (p = 0.68). The ASPECTS 4-5 group had lower TICI 2c-3 achievement (31% vs. 55%, p = 0.002) and poorer functional outcomes (mRS 0-1 at 90 days: 12% vs. 29%, p = 0.03) compared to the ASPECTS 6-7 group. Intracranial hemorrhagic complications were higher in the ASPECTS 4-5 group (69% vs. 47%, p = 0.007). Multivariable analysis revealed ASPECTS 6-7 to be associated with higher odds of TICI 2c-3 (OR: 2.5; CI: 1.28 to 4.89, p = 0.007) and lower odds of intracranial hemorrhagic complications (OR: 0.4; CI: 0.19 to 0.81, p = 0.012).

CONCLUSION

MT may be associated with improved outcomes in patients with moderate-to-low ASPECTS (6-7), though the lack of a control group limits definitive conclusions about its effectiveness. In patients with very low ASPECTS (4-5), higher rates of hemorrhagic complications and poorer outcomes were observed, but this does not necessarily preclude the use of MT. These findings highlight the need for further research and careful patient selection.

Larger Perfusion Mismatch Volume Is Associated With Longer Hospital Length of Stay in Medium Vessel Occlusion Stroke

BACKGROUND AND PURPOSE

Prolonged length of stay (LOS) following a stroke is associated with unfavorable clinical outcomes. Factors predicting LOS in medium vessel occlusion (MeVO), impacting up to 40% of acute ischemic stroke (AIS) cases, remain underexplored. This study aims to investigate the predictors of LOS in AIS-MeVO.

METHODS

We conducted a retrospective analysis of prospectively maintained stroke databases, comprising AIS cases with MeVO in the anterior circulation, assessed by adequate CT perfusion (CTP). Baseline and clinical data were obtained from electronic health records. Alberta Stroke Program Early CT Scores (ASPECTS) were calculated from non-contrast head CT. The perfusion mismatch volume (time to maximum > 6 s minus relative cerebral blood flow <30%) volume was reported from CTP. Multiple regression was employed to examine the relationship between baseline parameters and hospital LOS.

RESULTS

A total of 133 patients (median age 71 [interquartile range 63-80] years, 59.4% females) were included in the study cohort. The perfusion mismatch volume significantly positively correlated with LOS (r = 0.264, p = 0.004). After adjusting for age, sex, hypertension, diabetes, prior stroke or transient ischemic attack, admission NIHSS, ASPECTS, Tan score, intravenous thrombolysis, mechanical thrombectomy (MT), and hemorrhagic transformation, a larger mismatch volume remained independently associated with longer hospital stays (β = 0.209, 95% confidence interval [CI] 0.006-0.412, p = 0.045). Additional significant determinants of longer hospital stay included admission NIHSS (β = 0.250, 95% CI: 0.060-0.440, p = 0.010) and MT (β = 0.208, 95% CI: 0.006-0.410, p = 0.044). Among patients who underwent MT (n = 83), multiple regression analysis incorporating both perfusion mismatch volume and admission NIHSS revealed that perfusion mismatch volume remained independently associated with LOS (β = 0.248, 95% CI: 0.019-0.471, p = 0.033), while admission NIHSS did not retain significance (β = 0.208, 95% CI: 0.019-0.433, p = 0.071).

CONCLUSIONS

In our cohort of AIS patients with MeVO in the anterior circulation, and particularly in those who underwent MT, the perfusion mismatch volume serves as an independent predictor of LOS. These findings offer critical valuable insights in clinical assessments and decision-making protocols of MT in AIS-MeVO.

Safety and Efficacy of Conscious Sedation Versus General Anesthesia for Distal Vessel Thrombectomy

BACKGROUND AND OBJECTIVES

Anesthesia modality for endovascular thrombectomy (EVT) for distal and medium vessel occlusions remains an open question. General anesthesia (GA) may offer advantages over conscious sedation (CS) because of reduced patient movement facilitating catheter navigation, but concerns persist about potential delays and hypotension affecting collateral circulation.

METHODS

In our prospectively maintained stroke registry from December 2014 to July 2023, we identified patients with distal and medium vessel occlusions defined as M2, M3, or M4 occlusion; A1 or A2 occlusion; and P1 or P2 occlusion, who underwent EVT for acute ischemic stroke. We compared patients who received CS with those who received GA. Primary outcomes were early neurological improvement (ENI), successful reperfusion, first-pass effect, and good outcome at 90 days. Secondary outcomes included intracerebral hemorrhage, subarachnoid hemorrhage, and 90-day mortality.

RESULTS

Of 279 patients, 69 (24.7%) received GA, whereas 193 (69.2%) received CS. CS was associated with higher odds of ENI compared with GA (odds ratio [OR] 2.59, 95% CI [1.04-6.98], P < .05). CS was also associated with higher rates of successful reperfusion (OR 2.33, 95% CI [1.11-4.93], P < .05). CS nonsignificantly trended toward lower rates of mortality (OR 0.51, 95% CI [0.2-1.3], P = .16). No differences in good outcome at 90 days, intracerebral hemorrhage, subarachnoid hemorrhage, or first-pass effect were seen.

CONCLUSION

The use of CS during EVT seems to be safe and feasible with regard to successful recanalization, hemorrhagic complications, clinical outcome, and mortality. In addition, it may be associated with a higher rate of ENI. Further randomized studies in this specific EVT subpopulation are warranted.

Outcomes of mechanical thrombectomy in anticoagulated patients with acute distal and medium vessel stroke

BACKGROUND

Stroke remains a major health concern globally, with oral anticoagulants widely prescribed for stroke prevention. The efficacy and safety of mechanical thrombectomy (MT) in anticoagulated patients with distal medium vessel occlusions (DMVO) are not well understood.

METHODS

This retrospective analysis involved 1282 acute ischemic stroke (AIS) patients who underwent MT in 37 centers across North America, Asia, and Europe from September 2017 to July 2023. Data on demographics, clinical presentation, treatment specifics, and outcomes were collected. The primary outcomes were functional outcomes at 90 days post-MT, measured by modified Rankin Scale (mRS) scores. Secondary outcomes included reperfusion rates, mortality, and hemorrhagic complications.

RESULTS

Of the patients, 223 (34%) were on anticoagulation therapy. Anticoagulated patients were older (median age 78 vs 74 years; p < 0.001) and had a higher prevalence of atrial fibrillation (77% vs 26%; p < 0.001). Their baseline National Institutes of Health Stroke Scale (NIHSS) scores were also higher (median 12 vs 9; p = 0.002). Before propensity score matching (PSM), anticoagulated patients had similar rates of favorable 90-day outcomes (mRS 0-1: 30% vs 37%, p = 0.1; mRS 0-2: 47% vs 50%, p = 0.41) but higher mortality (26% vs 17%, p = 0.008). After PSM, there were no significant differences in outcomes between the two groups.

CONCLUSION

Anticoagulated patients undergoing MT for AIS due to DMVO did not show significant differences in 90-day mRS outcomes, reperfusion, or hemorrhage compared to non-anticoagulated patients after adjustment for covariates.

Second-dose intravenous thrombolysis with tenecteplase in alteplase-resistant medium-vessel-occlusion strokes: A retrospective and comparative study

INTRODUCTION

In intracranial medium-vessel occlusions (MeVOs), intravenous thrombolysis (IVT) shows inconsistent effectiveness and endovascular interventions remains unproven. We evaluated a new therapeutic strategy based on a second IVT using tenecteplase for MeVOs without early recanalization post-alteplase.

PATIENTS AND METHODS

This retrospective, comparative study included consecutively low bleeding risk MeVO patients treated with alteplase 0.9 mg/kg at two stroke centers. One center used a conventional single-IVT approach; the other applied a dual-IVT strategy, incorporating a 1-h post-alteplase MRI and additional tenecteplase, 0.25 mg/kg, if occlusion persisted. Primary outcomes were 24-h successful recanalization for efficacy and symptomatic intracranial hemorrhage (sICH) for safety. Secondary outcomes included 3-month excellent outcomes (modified Rankin Scale score of 0-1). Comparisons were conducted in the overall cohort and a propensity score-matched subgroup.

RESULTS

Among 146 patients in the dual-IVT group, 103 failed to achieve recanalization at 1 h and of these 96 met all eligible criteria and received additional tenecteplase. Successful recanalization at 24 h was higher in the 146 dual-IVT cohort patients than in the 148 single-IVT cohort patients (84% vs 61%, p < 0.0001), with similar sICH rate (3 vs 2, p = 0.68). Dual-IVT strategy was an independent predictor of 24-h successful recanalization (OR, 2.7 [95% CI, 1.52-4.88]; p < 0.001). Dual-IVT cohort patients achieved higher rates of excellent outcome (69% vs 44%, p < 0.0001). Propensity score matching analyses supported all these associations.

CONCLUSION

In this retrospective study, a dual-IVT strategy in selected MeVO patients was associated with higher odds of 24-h recanalization, with no safety concerns. However, potential center-level confounding and biases seriously limit these findings' interpretation.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05809921.

EnDovascular therapy plus best medical treatment (BMT) versus BMT alone for medIum distal veSsel occlusion sTroke (DISTAL): An international, multicentre, randomized-controlled, two-arm, assessor-blinded trial

RATIONALE

Whether endovascular therapy (EVT) in addition to best medical treatment (BMT) in people with acute ischemic stroke (AIS) due to a medium distal vessel occlusion (MDVO) is beneficial remains unclear.

AIM

To determine if people experiencing an AIS due to an isolated MDVO (defined as the co- or non-dominant M2 segment, the M3 or M4 segment of the middle cerebral artery, the A1, A2, or A3 segment of the anterior cerebral artery or the P1, P2 or P3 segment of the posterior cerebral artery) will have superior outcome if treated with EVT in addition to BMT compared to BMT alone.

SAMPLE SIZE

To randomize 526 participants 1:1 to EVT plus BMT or BMT alone.

METHODS AND DESIGN

A multicentre, international, prospective, randomized, open-label, blinded-endpoint (PROBE) superiority trial.

OUTCOMES

The primary efficacy endpoint is the distribution of disability levels on the modified Rankin Scale at 90 days. Secondary clinical efficacy outcomes include normalized change in National Institutes of Health Stroke Scale score from baseline to day 1, cognitive outcome at 90 days, and health-related quality of life at 90 days. Safety outcomes include all serious adverse events, symptomatic intracranial hemorrhage within 24 h, and all-cause mortality up to 90 days. Secondary imaging outcomes include successful reperfusion at end of EVT procedure and recanalization of target artery at 24 h.

DISCUSSION

DISTAL will inform physicians whether EVT in addition to BMT in people with AIS due to a MDVO is more efficacious than BMT alone.

Prevalence and Distribution of Intracranial Vessel Occlusion on Angiography and Its Association with Functional Outcome in Patients with Atrial Fibrillation Presenting with Ischemic Stroke

OBJECTIVES

To determine the prevalence and distribution of intracranial vessel occlusion identified on computed tomography (CT) or magnet resonance (MR) angiography and to explore its association with functional outcome in patients with atrial fibrillation (AF) and ischemic stroke.

METHODS

Multicenter cohort study enrolling consecutive patients with AF with imaging-confirmed ischemic stroke who underwent CT- or MR-angiography on admission (2014-2022). Multivariable regression was used to explore the association between intracranial vessel occlusion and poor functional outcome (modified Rankin Scale score 3-6) at 90 days.

RESULTS

The analysis included 10,164 patients (median age 81.5 years, 47.8% female, median National Institutes of Health Stroke Scale score on admission 6; 14.7% on a vitamin K antagonist [VKA], 27.5% on a direct oral anticoagulant [DOAC], 57.8% not receiving oral anticoagulation). Angiography showed intracranial vessel occlusion in 5,190 patients (51.1%), affecting the anterior cerebral circulation in 87.4%. Overall, 29.2% and 29.4% of patients received thrombolysis and mechanical thrombectomy, respectively. The proportion of patients with poor functional outcome at 90 days was 60.6% and 42.7% in those with and without vessel occlusion, respectively. In multivariable analyses, vessel occlusion was associated with poor functional outcome (adjusted odds ratio [aOR]: 1.95, 95% confidence interval [CI]: 1.71-2.22) with consistent results in subgroups according to oral anticoagulation use (VKA, aOR: 1.98, 95% CI: 1.40-2.80; DOAC, aOR: 2.35, 95% CI: 1.83-3.03; none, aOR: 1.76, 95% CI: 1.49-2.09).

INTERPRETATION

Intracranial vessel occlusion is common in patients with AF with ischemic stroke, mainly affects the anterior circulation and is associated with poor functional outcome. ANN NEUROL 2024;96:1115-1123.

Pretreatment predictors of very poor clinical outcomes in medium vessel occlusion stroke patients treated with mechanical thrombectomy

BACKGROUND

Acute ischemic stroke (AIS) from primary medium vessel occlusions (MeVO) is a prevalent condition associated with substantial morbidity and mortality. Despite the common use of mechanical thrombectomy (MT) in AIS, predictors of poor outcomes in MeVO remain poorly characterized.

METHODS

In this prospectively collected, retrospectively reviewed, multicenter, multinational study, data from the MAD-MT (Multicenter Analysis of primary Distal medium vessel occlusions: effect of Mechanical Thrombectomy) registry were analyzed. The study included 1568 patients from 37 academic centers across North America, Asia, and Europe, treated with MT, with or without intravenous tissue plasminogen activator (IVtPA), between September 2017 and July 2021.

RESULTS

Among the 1568 patients, 347 (22.2%) experienced very poor outcomes (modified Rankin score (mRS), 5-6). Key predictors of poor outcomes were advanced age (odds ratio (OR): 1.03; 95% confidence interval (CI): 1.02 to 1.04; p < 0.001), higher baseline National Institutes of Health Stroke Scale (NIHSS) scores (OR: 1.07; 95% CI: 1.05 to 1.10; p < 0.001), pre-operative glucose levels (OR: 1.01; 95% CI: 1.00 to 1.02; p < 0.001), and a baseline mRS of 4 (OR: 2.69; 95% CI: 1.25 to 5.82; p = 0.011). The multivariable model demonstrated good predictive accuracy with an area under the receiver-operating characteristic (ROC) curve of 0.76.

CONCLUSIONS

This study demonstrates that advanced age, higher NIHSS scores, elevated pre-stroke mRS, and pre-operative glucose levels significantly predict very poor outcomes in AIS-MeVO patients who received MT. These findings highlight the importance of a comprehensive risk assessment in primary MeVO patients for personalized treatment strategies. However, they also suggest a need for cautious patient selection for endovascular thrombectomy. Further prospective studies are needed to confirm these findings and explore targeted therapeutic interventions.

Outcomes with General Anesthesia Compared to Conscious Sedation for Endovascular Treatment of Medium Vessel Occlusions: Results of an International Multicentric Study

BACKGROUND

Optimal anesthetic strategy for the endovascular treatment of stroke is still under debate. Despite scarce data concerning anesthetic management for medium and distal vessel occlusions (MeVOs) some centers empirically support a general anesthesia (GA) strategy in these patients.

METHODS

We conducted an international retrospective study of MeVO cases. A propensity score matching algorithm was used to mitigate potential differences across patients undergoing GA and conscious sedation (CS). Comparisons in clinical and safety outcomes were performed between the two study groups GA and CS. The favourable outcome was defined as a modified Rankin Scale (mRS) 0-2 at 90 days. Safety outcomes were 90-days mortality and symptomatic intracranial hemorrhage (sICH). Predictors of a favourable outcome and sICH were evaluated with backward logistic regression.

RESULTS

After propensity score matching 668 patients were included in the CS and 264 patients in the GA group. In the matched cohort, either strategy CS or GA resulted in similar rates of good functional outcomes (50.1% vs. 48.4%), and successful recanalization (89.4% vs. 90.2%). The GA group had higher rates of 90-day mortality (22.6% vs. 16.5%, p < 0.041) and sICH (4.2% vs. 0.9%, p = 0.001) compared to the CS group. Backward logistic regression did not identify GA vs CS as a predictor of good functional outcome (OR for GA vs CS = 0.95 (0.67-1.35)), but GA remained a significant predictor of sICH (OR = 5.32, 95% CI 1.92-14.72).

CONCLUSION

Anaesthetic strategy in MeVOs does not influence favorable outcomes or final successful recanalization rates, however, GA may be associated with an increased risk of sICH and mortality.

Soft partial release of non-aggressive stent retriever technique for very distal arterial occlusion stroke

BACKGROUND

Endovascular thrombectomy (EVT) for very distal vessel occlusion (DVO) stroke is increasingly performed but there is insufficient evidence on the efficacy and safety of distal EVT techniques. We hypothesized that the technique of soft partial release of non-aggressive stent retrievers (SPORNS) reduces friction on the perforating vessels during thrombectomy and thereby reduces bleeding complications.

METHODS

Retrospective study including consecutive DVO patients who were treated with the SPORNS technique between 1 January 2022 and 31 December 2022 at two tertiary stroke centers. DVOs were defined as isolated occlusions of the M3 and M4 segments of the middle cerebral artery, occlusions of the A2 and A3 segments of the anterior cerebral artery, and occlusions of the P2 and P3 segments of the posterior cerebral artery or of the superior cerebellar artery. The technique is described in detail and procedural and clinical outcomes are given.

RESULTS

Twenty-four patients were treated with the SPORNS technique of whom 22 (92%) had complete or near complete recanalization (eTICI 2c/3). National Institutes of Health Stroke Scale (NIHSS) decreased from a median of nine (IQR 7-13) at admission to three (1-5) at discharge and 18 patients (75%) achieved a good outcome (modified Rankin scale 0-2) at day 90 post-stroke. Two patients (8%) had a small subarachnoid hemorrhage and two patients (8%) had a symptomatic intracerebral hemorrhage on follow-up imaging.

CONCLUSION

For the treatment of very distal arterial occlusions, the SPORNS technique employing a soft partial release of a non-aggressive stent retriever is safe and effective for the thrombectomy of small clots. The technique potentially yields a lower rate of subarachnoid hemorrhages while achieving an excellent rate of complete and first-pass recanalization.

A direct aspiration first-pass technique (ADAPT) for acute ischemic stroke thrombectomy: Indications, technique, and emerging devices

To date, the use of the most suitable first-pass technique for Mechanical Thrombectomy is still debated. In last years, several observational studies have suggested noninferiority or superiority of A Direct Aspiration first-Pass Technique (ADAPT) technique to achieve better reperfusion in comparison to stent retriever. While ASA/AHA 2018 guidelines recommend that patients with AIS should receive Mechanical Thrombectomy with a stent retriever, last European Stroke Organization guidelines report no evidence that stent retriever compared with contact aspiration could improve reperfusion rate. ADAPT is based on aspiration alone as the primary mechanism of thrombectomy and, if initially unsuccessful, then incorporating adjunctive alternatives. ADAPT improvement is also related to last generation of aspiration catheters. The purpose of this review is to report ADAPT principles, technique, efficacy, and safety as first-line treatment for acute ischemic stroke with the latest generation of reperfusion devices.

Direct Aspiration Versus Combined Technique for Anterior Distal, Medium Vessel Occlusions Stroke: The JET Distal Vessel Occlusion Study

BACKGROUND AND OBJECTIVES

The optimal mechanical thrombectomy technique for distal, medium vessel occlusion (DMVO) stroke remains unknown. We aimed to compare the safety and efficacy of 2 thrombectomy first-line approaches, direct aspiration (DA), and combined technique (CT) in patients with DMVOs.

METHODS

We conducted a retrospective review of a prospectively collected multicenter database of patients with DMVOs (at or distal to M2 and A1), who underwent mechanical thrombectomy with JET D reperfusion catheters between January 2020 and December 2021. The primary end point was the rate of first-pass complete recanalization, defined as modified treatment in cerebral infarction (mTICI) 3. The hemorrhagic complications, the 90 days functional independence rate (modified Rankin Scale 0-2), and mortality were also evaluated.

RESULTS

A total of 171 consecutive patients were enrolled (95 in DA and 76 in CT cohort). The 2 groups had comparable demographics and baseline characteristics. The DA group had a higher rate of first-pass effect (40.0% vs 10.5%, P < .001), final mTICI 2b-3 (89.5% vs 71.1%, P = .003) and final mTICI 3 (58.9% vs 28.9%, P < .001), shorter groin to reperfusion time (65 ± 43 min vs 101 ± 60 min, P < .001), and higher rate of 90-day functional independence (63.7% vs 36.1%; P = .001) compared with the CT group. There were no significant differences in hemorrhagic complications between the 2 groups. The DA group showed a lower rate of 90-day mortality (9.9% vs 27.8%; P = .004).

CONCLUSION

In patients with DMVOs, DA with a distal dedicated reperfusion catheter appears to demonstrate better safety and efficacy when compared with the CT using the same catheter.

Heterogeneous multiple soft millirobots in three-dimensional lumens

Miniature soft robots offer opportunities for safe and physically adaptive medical interventions in hard-to-reach regions. Deploying multiple robots could further enhance the efficacy and multifunctionality of these operations. However, multirobot deployment in physiologically relevant three-dimensional (3D) tubular structures is limited by the lack of effective mechanisms for independent control of miniature magnetic soft robots. This work presents a framework leveraging the shape-adaptive robotic design and heterogeneous resistance from robot-lumen interactions to enable magnetic multirobot control. We first compute influence and actuation regions to quantify robot movement. Subsequently, a path planning algorithm generates the trajectory of a permanent magnet for multirobot navigation in 3D lumens. Last, robots are controlled individually in multilayer lumen networks under medical imaging. Demonstrations of multilocation cargo delivery and flow diversion manifest their potential to enhance biomedical functions. This framework offers a solution to multirobot actuation benefiting applications across different miniature robotic devices in complex environments.

Finding MeVO: Identifying Intracranial Medium-Vessel Occlusions at CT Angiography

The development of methods to detect and treat intracranial large-vessel occlusions (LVOs) has revolutionized the management of acute ischemic stroke. CT angiography (CTA) of the head and neck is effective in depicting LVOs and widely used in the evaluation of patients who have had a stroke. Ongoing efforts are now focused on the potential to detect and treat intracranial medium-vessel occlusions (MeVOs), which by definition are smaller than LVOs and thus more difficult to detect with CTA. The authors review common and variant anatomies of medium-sized cerebral arteries and the appearance of a variety of MeVOs on CT angiograms. Possible pitfalls in MeVO detection include rare anatomic variants, calcified thrombi, and stump occlusions. Current recommendations for performing CTA and ancillary methods that might aid in MeVO detection are discussed. Understanding the relevant anatomy and the variety of appearances of MeVOs aids radiologists in identifying these occlusions, particularly in the setting of urgent stroke. ©RSNA, 2024 See the invited commentary by Ospel and Nguyen in this issue.

Clinical comparison of aspiration to stentriever-mediated aspiration thrombectomy for M2 occlusions

OBJECTIVE

While revascularization for M2 occlusions is generally recommended and considered beneficial, the optimal approach (aspiration vs stentriever/combined) is less well defined in the literature. We sought to compare outcomes after thrombectomy with manual aspiration thrombectomy alone (MAT) or stentriever-mediated aspiration thrombectomy (SMAT) MATERIALS AND METHODS: To circumvent inter-operator technical variability, patients underwent thrombectomy for M2 occlusions by a single operator and were stratified by first pass approach: manual aspiration thrombectomy (MAT/aspiration alone) and stentriever-mediated manual aspiration thrombectomy (SMAT/combination). Efficacy outcomes included good reperfusion (mTICI score ≥2b) and a favorable 90-day functional outcome (mRS score of ≤2). Safety outcomes included 90-day mortality and symptomatic intracranial hemorrhage.

RESULTS

One hundred three patients were identified: 57 underwent MAT whereas 46 underwent SMAT. Good reperfusion (TICI 2b or greater) was comparable between groups (93.5 % vs. 87.7 %, P=0.33). The intracranial hemorrhage rate was higher with SMAT compared to MAT (13 % vs. 1.8 %, P=0.04). Puncture-to-recanalization time was longer in SMAT (34.4 vs. 19.9 minutes, P<0.001). In multivariable analysis, complete or good reperfusion was associated with shorter puncture-recanalization time (adjusted odds ratio [aOR], 0.85) or less total passes (aOR, 0.58), respectively. In a propensity score matched analysis of 66 patients with comparable baseline and technical efficiency, the safety outcomes were not different between SMAT and MAT groups.

CONCLUSIONS

SMAT compared with MAT did not result in an improved revascularization rate or functional outcome, while it was related to more hemorrhagic complications and mortality. Given cost and time savings with manual aspiration alone, this approach may be optimal as first line for M2 occlusions.

First-Line Aspiration Thrombectomy of M2 Occlusions with a Novel Reperfusion Catheter (REDTM 62): Real-World Experience from Two Tertiary Comprehensive Stroke Centers

PURPOSE

The direct aspiration first pass technique (ADAPT) is an effective and safe endovascular treatment for distal medium vessel occlusions (DMVOs). We evaluated technical features and initial results of a novel reperfusion catheter (REDTM 62) used for frontline aspiration thrombectomy of M2 occlusions in acute ischemic stroke patients. Appropriate aspiration catheters are crucial for a successful ADAPT maneuver; however, the selection of catheters suitable for smaller-sized vessels is scarce compared to the ones for large vessel occlusions.

MATERIALS AND METHODS

All patients treated with ADAPT using REDTM 62 as the frontline treatment approach for acute M2 occlusions between December 2022 and February 2024 were retrospectively enrolled. Demographic data, procedural timings and safety, recanalization rates, and outcome data were recorded.

RESULTS

Twenty patients with a median admission National Institutes of Health Stroke Scale (NIHSS) score of 8 were identified. Successful revascularization (DMVO-thrombolysis in cerebral infarction [TICI]≥2b) with REDTM 62 aspiration thrombectomy was obtained in 65.0% (13/20) of cases. The first pass effect was 45.0% (9/20). In 2 cases, the REDTM 62 did not reach the clot due to marked distal vessel tortuosity. Stent retrievers were additionally used in 9 cases and led to an overall DMVO-TICI 2c/3 of 90.0% (18/20). Mean procedural time was 48 minutes. No complications directly related to ADAPT occurred. In-hospital mortality rate was 20.0% (4/20). The median discharge NIHSS score was 2.5. A good functional outcome at discharge (modified Rankin scale 0-2) was achieved in 55.0% (11/20) of cases.

CONCLUSION

Our initial experiences with the novel REDTM 62 reperfusion catheter for treatment of M2 occlusions is in line with published data. ADAPT using this catheter may be considered as a safe and effective first-line treatment option. Further studies are warranted to validate the initial results.

Mechanical Thrombectomy for Treatment of Acute Cerebral Infarction due to Distal Medium Vessel Occlusions: A Retrospective Cohort Study

BACKGROUND

Mechanical thrombectomy (MT) is standard of care for acute cerebral infarction (ACI) due to large vessel occlusions. However, its clinical efficacy in patients with ACI due to distal medium vessel occlusions (DMVOs) remains unclear. This study evaluates the efficacy and safety of MT in patients with ACI due to DMVOs.

METHODS

Totally, 306 patients with ACI at a very early stage were assigned into DMVOs-MT, M1-MT, and DMVOs-intravenous thrombolysis (IVT) groups. These groups were compared regarding baseline data, recanalization rate, location of vessel occlusions, number of thrombectomy, first-pass recanalization, mRS scores, NIHSS scores, 90-day mRS scores, incidence of adverse events, and mortality. Risk factors for poor prognosis of patients with DMVOs following MT were analyzed.

RESULTS

DMVOs-MT and M1-MT groups showed comparable first-pass recanalization rates, recanalization rates, and NIHSS score reduction ratios, with marked differences in location of vessel occlusions. Versus DMVOs-IVT, DMVOs-MT had increased differences between pre- and post-treatment NIHSS scores and between pre-treatment NIHSS scores and NIHSS scores at discharge and elevated NIHSS reduction ratios. The poor prognosis rate of DMVOs-MT group was insignificantly different from that of M1-MT group but lower than that of DMVOs-IVT group. Adverse events and mortality incidences were comparable among the three groups. Diabetes, first-pass recanalization, and pre-treatment NIHSS scores were independent risk factors for poor prognosis in DMVO patients after MT.

CONCLUSION

MT is as effective and safe in patients with DMVOs as in patients with M1 occlusions. In patients with DMVOs, MT has higher efficacy and safety than IVT.

Utility of automated CT perfusion software in acute ischemic stroke with large and medium vessel occlusion

BACKGROUND

Early diagnosis of large vessel occlusion (LVO) in acute stroke often requires CT angiography (CTA). Automated CT perfusion (CTP) software, which identifies blood flow abnormalities, enhances LVO diagnosis and patient selection for endovascular thrombectomy (EVT). This study evaluates the sensitivity of automated CTP images in detecting perfusion abnormalities in patients with acute ischemic stroke (AIS) and LVO or medium vessel occlusion (MeVO), compared to CTA.

METHODS

We screened acute ischemic stroke patients presenting within 24 h who underwent CT, CTA, and CTP as per institutional protocol. RAPID AI software processed CTP images, while neuroradiologists reviewed CTA for intracranial arterial occlusions. Sensitivity, specificity, and accuracy of automated CTP maps in detecting occlusions were assessed.

RESULTS

Of 790 screened patients, 31 were excluded due to lack of RAPID CTP data or poor-quality scans, leaving 759 for analysis. The median age was 71 years (IQR: 61-81), with 47% female. Among them, 678 had AIS, and 81 had AIS ruled out. CTA identified arterial occlusion in 562 patients (74%), with corresponding CTP abnormalities in 537 patients (Tmax > 6 sec). In the 197 without occlusion, CTP was negative in 161. Automated CTP maps had a sensitivity of 95.55% (CI 95: 93.50-97.10%), specificity of 81.73% (CI 95: 75.61-86.86%), negative predictive value of 98.22% (CI 95: 97.39-98.79%), positive predictive value of 63.54% (CI 95: 56.46-70.09%), and overall accuracy of 85.18% (CI 95: 82.45-87.64%).

CONCLUSIONS

Automated CTP maps demonstrated high sensitivity and negative predictive value for LVOs and MeVOs, suggesting their usefulness as a rapid diagnostic tool, especially in settings without expert neuroradiologists.

Impact of deep Learning-enhanced contrast on diagnostic accuracy in stroke CT angiography

PURPOSE

To examine the impact of deep learning-augmented contrast enhancement on image quality and diagnostic accuracy of poorly contrasted CT angiography in patients with suspected stroke.

METHODS

This retrospective single-centre study included 102 consecutive patients who underwent CT imaging for suspected stroke between 01/2021 and 12/2022, including whole brain volume perfusion CT (VPCT) and, specifically, a poorly contrasted CT angiography (defined as < 350HU in the proximal MCA). CT angiography imaging data was reconstructed using i.) an iterative reconstruction kernel (conventional CTA, c-CTA) as well as ii.) an iodine-based contrast boosting deep learning model (Deep Learning-enhanced CTA, DLe-CTA). For quantitative analysis, the slope, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) were determined. Qualitative image analysis was conducted by three readers, rating image quality and vessel-specific parameters on a 4-point Likert scale. Readers evaluated both datasets for cerebral vessel occlusion presence. VPCT served as the reference standard for calculating sensitivity and specificity.

RESULTS

102 patients were evaluated (mean age 69 ± 13 years; 70 men). DLe-CTA outperformed c-CTA in quantitative (all items p < 0.001) and qualitative image analysis (all items p < 0.05). VPCT revealed 58/102 patients with vascular occlusion. DLe-CTA resulted in significantly higher sensitivity compared to c-CTA (p < 0.001); (all readers put together: c-CTA: 142/174 [81.6 %; 95 % CI: 75.0 %-87.1 %] vs. DLe-CTA 163/174 [94 %; 95 % CI: 89.0 %-96.8 %]). One false positive finding occurred on DLe-CTA (specificity 1/132) [99.2 %; 95 % CI: 95.9 %-100 %].

CONCLUSIONS

Deep learning-augmented contrast enhancement improves the image quality and increases the sensitivity of detection vessel occlusions in poorly contrasted CTA.

Endovascular therapy versus medical management in isolated posterior cerebral artery acute ischemic stroke: A multinational multicenter propensity score-weighted study

BACKGROUND

Despite the proven effectiveness of endovascular therapy (EVT) in acute ischemic strokes (AIS) involving anterior circulation large vessel occlusions, isolated posterior cerebral artery (PCA) occlusions (iPCAo) remain underexplored in clinical trials. This study investigates the comparative effectiveness and safety of EVT against medical management (MM) in patients with iPCAo.

METHODS

This multinational, multicenter propensity score-weighted study analyzed data from the Multicenter Analysis of primary Distal medium vessel occlusions: effect of Mechanical Thrombectomy (MAD-MT) registry, involving 37 centers across North America, Asia, and Europe. We included iPCAo patients treated with either EVT or MM. The primary outcome was the modified Rankin Scale (mRS) at 90 days, with secondary outcomes including functional independence, mortality, and safety profiles such as hemorrhagic complications.

RESULTS

A total of 177 patients were analyzed (88 MM and 89 EVT). EVT showed a statistically significant improvement in 90-day mRS scores (OR = 0.55, 95% CI = 0.30-1.00, p = 0.048), functional independence (OR = 2.52, 95% CI = 1.02-6.20, p = 0.045), and a reduction in 90-day mortality (OR = 0.12, 95% CI = 0.03-0.54, p = 0.006) compared to MM. Hemorrhagic complications were not significantly different between the groups.

CONCLUSION

EVT for iPCAo is associated with better neurological outcomes and lower mortality compared to MM, without an increased risk of hemorrhagic complications. Nevertheless, these results should be interpreted with caution due to the study's observational design. The findings are hypothesis-generating and highlight the need for future randomized controlled trials to confirm these observations and establish definitive treatment guidelines for this patient population.

The Vecta 46 intermediate catheter for mechanical thrombectomy of distal medium vessel occlusions: A single-center experience

INTRODUCTION

With emerging evidence supporting the clinical efficacy and safety of mechanical thrombectomy (MT) for distal medium vessel occlusions (DMVOs), MT devices specifically designed to navigate through smaller caliber and more delicate tortuous distal cerebrovasculature are required. This study describes our single-center experience using the AXS Vecta 46 intermediate catheter for first-line thromboaspiration of DMVOs.

METHODS

We identified all patients who underwent MT using the Vecta 46 for first-line thromboaspiration for primary or secondary DMVOs. We collected baseline clinical data, angiographic and clinical outcomes, as well as procedural complications. The primary outcome in question was the rate of successful recanalization, which was defined as a modified Thrombolysis in Cerebral Infarction score of ≥2b.

RESULTS

We identified 43 patients who underwent MT using the Vecta 46 catheter for thromboaspiration of 54 DMVOs. Intervened vessels included the M2 (23/54), M3 (19/54), and M4 (6/54) branches of the middle cerebral artery, A2 (1/54), A3 (1/54), and A4 (1/54) branches of the anterior cerebral artery, and P1 (1/54), P2 (1/54), and P4 (1/54) branches of the posterior cerebral artery. The median number of passes for primary DMVOs was 2 (IQR: 1-3) and 1 (IQR: 1-1.25) for secondary DMVOs. The rate of successful recanalization was 100% (18/18) for primary DMVOs and 80.6% (29/36) for secondary DMVOs. First-pass effect (FPE) was noted in 55.6% (30/54) of all primary and secondary DMVO cases. Improved short-term clinical outcomes were observed in both the primary (National Institute of Health Stroke Scale [NIHSS] shift: -5 [IQR: -14.25 to -0.25]) and secondary (NIHSS shift: -5 [IQR: -10 to -2]) DMVO groups. A total of six patients died during their hospitalization, though none were deemed procedural-related.

CONCLUSIONS

Our study demonstrates the safety and efficacy of the Vecta 46 intermediate catheter for thromboaspiration of both primary and secondary DMVOs, achieving high rates of successful recanalization and FPE.

Comprehensive analysis of the impact of procedure time and the 'golden hour' in subpopulations of stroke thrombectomy patients

OBJECTIVE

To evaluate the effect of procedure time on thrombectomy outcomes in different subpopulations of patients undergoing endovascular thrombectomy (EVT), given the recently expanded indications for EVT.

METHODS

This multicenter study included patients undergoing EVT for acute ischemic stroke at 35 centers globally. Procedure time was defined as time from groin puncture to successful recanalization (Thrombolysis in Cerebral Infarction score ≥2b) or abortion of procedure. Patients were stratified based on stroke location, use of IV tissue plasminogen activator (tPA), Alberta Stroke Program Early CT score, age group, and onset-to-groin time. Primary outcome was the 90-day modified Rankin Scale (mRS) score, with scores 0-2 designating good outcome. Secondary outcome was postprocedural symptomatic intracranial hemorrhage (sICH). Multivariate analyses were performed using generalized linear models to study the impact of procedure time on outcomes in each subpopulation.

RESULTS

Among 8961 patients included in the study, a longer procedure time was associated with higher odds of poor outcome (mRS score 3-6), with 10% increase in odds for each 10 min increment. When procedure time exceeded the 'golden hour', poor outcome was twice as likely. The golden hour effect was consistent in patients with anterior and posterior circulation strokes, proximal or distal occlusions, in patients with large core infarcts, with or without IV tPA treatment, and across age groups. Procedures exceeding 1 hour were associated with a 40% higher sICH rate. Posterior circulation strokes, delayed presentation, and old age were the variables most sensitive to procedure time.

CONCLUSIONS

In this work we demonstrate the universality of the golden hour effect, in which procedures lasting more than 1 hour are associated with worse clinical outcomes and higher rates of sICH across different subpopulations of patients undergoing EVT.

Mechanical thrombectomy practices in Europe: Insights from a survey of European neuroradiologists from the ESMINT

BACKGROUND AND PURPOSE

Mechanical thrombectomy (MT) has revolutionized the prognosis of acute ischemic stroke. Indications for MT are constantly expanding across countries, presenting healthcare professionals, and institutions with the challenge of offering MT to the entire population despite geographic constraints, while also training enough interventional neuroradiologists (INR) for this highly technical-level procedure. We aimed to provide an overview of current European MT practices and organizations in 2021.

MATERIALS AND METHODS

Members of the European Society of Minimally Invasive Neurological Therapy (ESMINT) were invited to complete two different online surveys from March to November 2021 to collect data on MT practice.

RESULTS

A total of 240 individual responses from INR (from 33 European countries) were received. These included information from 56 thrombectomy-capable stroke centers (TCSC) data (across 26 European countries). The mean number of INR per center was 3.8 ± 1.43, median 4 (IQR, 3-4.5). Half of the centers (28/56, 50.00%) performed less than 150 MT per year. Most INR used a balloon guide catheter in less than 50% of cases (160/240, 66.67%), and limited the number of recanalization attempts to six passes to restore flow (209/240, 87.08%). Additionally, 37.92% of the respondents (91/240, 37.92%) indicated that they already performed MT for distal occlusions (M3, M4) as part of their routine practice. Other details of the MT procedure, anesthetic management, and patient selection are also presented and discussed.

CONCLUSIONS

This European survey emphasizes the differences between TCSC and INR in modern thrombectomy practices. Even if most centers remain understaffed to meet current and future MT needs, most European TCSCs are actively training young INR.

Flow reduction due to arterial catheterization during stroke treatment - A computational study using a distributed compartment model

The effectiveness of various stroke treatments depends on the anatomical variability of the cerebral vasculature, particularly the collateral blood vessel network. Collaterals at the level of the Circle of Willis and distal collaterals, such as the leptomeningeal arteries, serve as alternative avenues of flow when the primary pathway is obstructed during an ischemic stroke. Stroke treatment typically involves catheterization of the primary pathway, and the potential risk of further flow reduction to the affected brain area during this treatment has not been previously investigated. To address this clinical question, we derived the lumped parameters for catheterized blood vessels and implemented a corresponding distributed compartment (0D) model. This 0D model was validated against an experimental model and benchmark test cases solved using a 1D model. Additionally, we compared various off-center catheter trajectories modeled using a 3D solver to this 0D model. The differences between them were minimal, validating the simplifying assumption of the central catheter placement in the 0D model. The 0D model was then used to simulate blood flows in realistic cerebral arterial networks with different collateralization characteristics. Ischemic strokes were modeled by occlusion of the M1 segment of the middle cerebral artery in these networks. Catheters of different diameters were inserted up to the obstructed segment and flow alterations in the network were calculated. Results showed up to 45% maximum blood flow reduction in the affected brain region. These findings suggest that catheterization during stroke treatment may have a further detrimental effect for some patients with poor collateralization.