Why we fail: mechanisms and co-factors of unsuccessful thrombectomy in acute ischemic stroke

A Deep Learning Approach to Predict Recanalization First-Pass Effect following Mechanical Thrombectomy in Patients with Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Following endovascular thrombectomy in patients with large-vessel occlusion stroke, successful recanalization from 1 attempt, known as the first-pass effect, has correlated favorably with long-term outcomes. Pretreatment imaging may contain information that can be used to predict the first-pass effect. Recently, applications of machine learning models have shown promising results in predicting recanalization outcomes, albeit requiring manual segmentation. In this study, we sought to construct completely automated methods using deep learning to predict the first-pass effect from pretreatment CT and MR imaging.

MATERIALS AND METHODS

Our models were developed and evaluated using a cohort of 326 patients who underwent endovascular thrombectomy at UCLA Ronald Reagan Medical Center from 2014 to 2021. We designed a hybrid transformer model with nonlocal and cross-attention modules to predict the first-pass effect on MR imaging and CT series.

RESULTS

The proposed method achieved a mean 0.8506 (SD, 0.0712) for cross-validation receiver operating characteristic area under the curve (ROC-AUC) on MR imaging and 0.8719 (SD, 0.0831) for cross-validation ROC-AUC on CT. When evaluated on the prospective test sets, our proposed model achieved a mean ROC-AUC of 0.7967 (SD, 0.0335) with a mean sensitivity of 0.7286 (SD, 0.1849) and specificity of 0.8462 (SD, 0.1216) for MR imaging and a mean ROC-AUC of 0.8051 (SD, 0.0377) with a mean sensitivity of 0.8615 (SD, 0.1131) and specificity 0.7500 (SD, 0.1054) for CT, respectively, representing the first classification of the first-pass effect from MR imaging alone and the first automated first-pass effect classification method in CT.

CONCLUSIONS

Results illustrate that both nonperfusion MR imaging and CT from admission contain signals that can predict a successful first-pass effect following endovascular thrombectomy using our deep learning methods without requiring time-intensive manual segmentation.

Percutaneous Closure Device for the Carotid artery: An integrated review and design analysis

Endovascular thrombectomies (EVTs) are the current standard of care therapy for treating acute ischemic strokes. While access through the femoral or radial arteries is routine, up to 20% of EVTs through these sites are unable to access the cerebral vasculature on the first pass. These shortcomings are commonly due to tortuous vasculature, atherosclerotic arteries, and type III aortic arch, seen especially in the elderly population. Recent studies have shown the benefits of accessing the cerebral vasculature through a percutaneous direct carotid puncture (DCP), which can reduce the time of the procedure by half. However, current vascular closure devices (VCDs) designed for the femoral artery are not suited to close the carotid artery due to the anatomical differences. This unmet clinical need further limits a DCP approach. Thus, to foster safe adoption of this potential approach, a VCD designed specifically for the carotid artery is needed. In this review, we outline the major biomechanical properties and shortcomings of current VCDs and propose the requirements necessary to effectively design and develop a carotid closure device.

Catheter navigation support for mechanical thrombectomy guidance: 3D/2D multimodal catheter-based registration with no contrast dye fluoroscopy

PURPOSE

The fusion of pre-operative imaging and intra-operative fluoroscopy may support physicians during mechanical thrombectomy for catheter navigation from the aortic arch to carotids. Nevertheless, the aortic arch volume is too important for intra-operative contrast dye injection leading to a lack of common anatomical structure of interest that results in a challenging 3D/2D registration. The objective of this work is to propose a registration method between pre-operative 3D image and no contrast dye intra-operative fluoroscopy.

METHODS

The registration method exploits successive 2D fluoroscopic images of the catheter navigating in the aortic arch. The similarity measure is defined as the normalized cross-correlation between a binary combination of catheter images and a pseudo-DRR resulting from the 2D binary projection of the pre-operative 3D image (MRA or CTA). The 3D/2D transformation is decomposed in out-plane and in-plane transformations to reduce computational complexity. The 3D/2D transformation is then obtained by maximizing the similarity measure through multiresolution exhaustive search.

RESULTS

We evaluated the registration performance through dice score and mean landmark error. We evaluated the influence of parameters setting, aortic arch type and 2D navigation sequence duration. Results on a physical phantom and data from a patient who underwent a mechanical thrombectomy showed good registration accuracy with a dice score higher than 92% and a mean landmark error lower than the quarter of a carotid diameter (8-10 mm).

CONCLUSION

A new registration method compatible with no contrast dye fluoroscopy has been proposed to guide the crossing from aortic arch to a carotid in mechanical thrombectomy. First evaluation showed the feasibility and accuracy of the method as well as its compatibility with clinical routine practice.

Rendezvous intervention using combined surgical carotid endarterectomy followed by endovascular thrombectomy in patients with acute tandem occlusions: a proof-of-concept experience at a tertiary care center

BACKGROUND

Endovascular thrombectomy (EVT) is highly effective in acute stroke patients with intracranial large vessel occlusion (LVO), however, presence of concomitant cervical occlusion of the internal carotid artery (ICA) may limit the endovascular access. This study describes feasibility and efficacy of a surgical carotid access (cutdown) to perform interdisciplinary recanalization therapy including carotid endarterectomy (CEA) followed by EVT for recanalization of intracranial LVO in stroke patients with tandem occlusions.

METHODS

We identified stroke patients with tandem occlusions who underwent a combined surgical-endovascular approach over a 5-year period. Surgical cutdown was provided by a cardiovascular surgery team at the angio-suite followed by EVT performed by the neuroradiological team. Demographics, stroke characteristics, treatments including antithrombotic management, procedure times, and clinical follow-up were assessed.

RESULTS

Four patients with acute stroke because of tandem occlusions received CEA followed by EVT (two patients after frustrating femoral catheterization, two as first-line approach). Successful recanalization (TICI ≥ 2b) via endovascular thrombectomy was achieved in all patients at a median of 28 min after successful surgical CEA. Intraprocedural complication was observed in one case (25%; i.e. ICA dissection).

CONCLUSIONS

This small study provides evidence that a combined interdisciplinary approach of CEA followed by EVT in the angio-suite in acute stroke patients with tandem occlusions is a feasible procedure in patients otherwise not accessible to endovascular recanalizing therapy and, therefore, high likelihood of developing large hemispheric infarction. Prospective data are warranted to identify patients who benefit from this combined approach as first-line therapy.

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

BACKGROUND

Mechanical thrombectomy failure (MTF) occurs in approximately 15% of cases.

OBJECTIVE

To investigate factors that predict MTF.

METHODS

This was a retrospective review of prospectively collected data from the Stroke Thrombectomy and Aneurysm Registry. Patients who underwent mechanical thrombectomy (MT) for large vessel occlusion (LVO) were included. Patients were categorized by mechanical thrombectomy success (MTS) (≥mTICI 2b) or MTF (

RESULTS

A total of 6780 patients were included, and 1001 experienced anterior circulation MTF. Patients in the MTF group were older (73 vs 72, P = .044) and had higher poor premorbid modified Rankin Scale (mRS) (10.8% vs 8.4%, P = .017). Onset to puncture time was greater in the MTF group (273 vs 260 min, P = .08). No significant differences were found between the access site, use of balloon guide catheter, frontline technique, or first-pass devices between the MTF and MTS groups. More complications occurred in the MTF group (14% vs 5.8%), including symptomatic intracerebral hemorrhage (9.4% vs 6.1%) and craniectomies (10% vs 2.8%) ( P < .001). On UVA, age, poor pretreatment mRS, increased number of passes, and increased procedure time were associated with MTF. Internal carotid artery, M1, and M2 occlusions had decreased odds of MTF. Poor preprocedure mRS, number of passes, and procedure time remained significant on MVA. A subgroup analysis of posterior circulation LVO revealed that number of passes and total procedure time correlated with increased odds of MTF ( P < .001) while rescue stenting was associated with less odds of MTF (odds ratio 0.20, 95% CI 0.06-0.63). Number of passes remained significant on MVA of posterior circulation occlusion subgroup analysis.

CONCLUSION

Anterior circulation MTF is associated with more complications and worse outcomes. No differences were found between techniques or devises used for the first pass during MT. Rescue intracranial stenting may decrease the likelihood of MTF for posterior circulation MT.

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Key Words Collapse

MESH Headings

• Humans
• Stroke/surgery
• Thrombectomy/methods
• Cerebral Hemorrhage
• Retrospective Studies
• Aneurysm
• Registries
• Treatment Outcome
• Brain Ischemia/therapy

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Affiliation(s)

Matthew Webb Department of Neurosurgery, University of Texas Health Science Center San Antonio, San Antonio , Texas , USA
Muhammed Amir Essibayi Medical University of South Carolina, Charleston , South Carolina , USA
Sami Al Kasab Medical University of South Carolina, Charleston , South Carolina , USA
Ilko L Maier University Medical Center Göttingen, Göttingen , Germany
Marios-Nikos Psychogios University Hospital Basel, Basel , Switzerland
Jonathan A Grossberg Emory University, Atlanta , Georgia , USA
Ali Alawieh Emory University, Atlanta , Georgia , USA
Stacey Quintero Wolfe Wake Forest University, Winston-Salem , North Carolina , USA
Adam Arthur University of Tennessee Health Science Center, Memphis , Tennessee , USA
Travis Dumont Bannner University of Arizona Medical Center, Tucson , Arizona , USA
Peter Kan University of Texas Medical Branch, Galveston , Texas , USA
Joon-Tae Kim Chonnam National University Hospital, Gwangju , South Korea
Reade De Leacy Mount Sinai Health System, New York , New York , USA
Joshua Osbun Washington University in St. Louis, St. Louis , Missouri , USA
Ansaar Rai Department of Neuroradiology, School of Medicine, West Virginia University, Morgantown, West Virginia, USA
Pascal Jabbour Department of Neuroradiology, School of Medicine, West Virginia University, Morgantown, West Virginia, USA
Min S Park Thomas Jefferson University Hospital, Philadelphia , Pennsylvania , USA
Roberto Crosa University of Virginia, Charlottesville , Virginia , USA
Michael R Levitt Centro Endovascular Neurológico, Médica Uruguaya, Montevideo , Uruguay
Adam Polifka University of Washington, Seattle , Washington , USA
Shinichi Yoshimura University of Florida, Gainesville , Florida , USA
Charles Matouk Hyogo College of Medicine, Nishinomiya , Japan
Richard W Williamson Yale School of Medicine, New Haven , Connecticut , USA
Isabel Fragata Allegheny General Hospital, Pittsburgh , Pennsylvania , USA
Shakeel A Chowdhry Centro Hospitalar Universitário de Lisboa Central, Lisboa , Portugal
Robert M Starke NorthShore University Health System, Evanston , Illinois , USA
Edgar A Samaniego University of Miami Health System, Miami , Florida , USA
Hugo Cuellar University of Iowa, Iowa City , Iowa , USA
Alejandro Spiotta Medical University of South Carolina, Charleston , South Carolina , USA
Justin Mascitelli Department of Neurosurgery, University of Texas Health Science Center San Antonio, San Antonio , Texas , USA

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Piecing Arterial Branching Pattern Together from Non-Contrast and Angiographic Brain Computed Tomography before Endovascular Thrombectomy for Acute Ischemic Stroke

Predicting the unseen arterial course and branching pattern distal to vessel occlusion is crucial for endovascular thrombectomy in acute stroke patients. We investigated whether a comprehensive interpretation of NCT and CTA would enhance arterial course prediction more than either NCT or CTA interpretation alone. Among 150 patients who achieved post-thrombectomy TICI grades ≥ IIb for anterior circulation occlusions, we assessed visualization grade on both NCT and CTA by five scales at the thrombosed and the distal-to-thrombus segment, using DSA as the reference standard. The visualization grades were compared and related to various subgroups. The mean visualization grade of the distal-to-thrombus segment on NCT was significantly larger than that of CTA (mean ± SD, 3.62 ± 0.87 versus 3.31 ± 1.20; p < 0.05). On CTA, visualization grade of distal-to-thrombus segment in the good collateral flow subgroup was higher than that in the poor collateral flow subgroup (mean ± SD, 4.01 ± 0.93 versus 2.56 ± 0.99; p < 0.001). After the comprehensive interpretation of NCT and CTA, seventeen cases (11%) showed visualization grade of distal-to-thrombus segment upgrading. Tracing arterial course and piecing branching patterns together in distal-to-occlusion of stroke patients was feasible on the routine pre-interventional NCT and CTA, which may provide timely guidance during thrombectomy.

Balloon Gliding Technique: A novel use of balloon guiding catheters in accessing challenging circulations when treating acute ischemic stroke

BACKGROUND

Challenging arterial anatomy delays, or prevents timely endovascular treatment (EVT) of acute ischemic stroke (AIS). We introduce a new technique called 'Balloon Gliding Technique (BGT)' to overcome difficult arterial anatomy during EVT of AIS, utilizing flow-assistance to access challenging circulations.

METHODS

Retrospective review of a prospectively collected database of all patients presenting to a single institution with AIS who underwent EVT was performed from January 2021 to June 2021. Patients in whom BGT was performed were assessed. BGT consists of advancing the balloon guide catheter in the cervical carotid artery while its balloon is inflated, and therefore carried by downstream flow.

RESULTS

Of 51 patients presenting with AIS secondary to large vessel occlusion during the study period, five patients underwent BGT. All five patients had anterior circulation large vessel occlusions. Mean age of the BGT patients was 92.2 years, and all patients were females. A type 3 arch was present in all patients. BGT was performed in all cases following initial failure of conventional techniques to cannulate the target circulation. BGT was successful in achieving distal cervical carotid access in 4 out of the 5 patients in whom BGT was attempted. Successful recanalization (modified treatment in cerebral ischemia 2b-3) was obtained in all cases with no complications.

CONCLUSIONS

Balloon Gliding Technique (BGT) is a safe technique that can safely overcome challenging anatomy during endovascular treatment of acute ischemic stroke. Further studies can assist in demonstrating both its safety and effectiveness.

Stenting and Angioplasty in Neurothrombectomy: Matched Analysis of Rescue Intracranial Stenting Versus Failed Thrombectomy

BACKGROUND:

Successful reperfusion is one of the strongest predictors of functional outcomes after mechanical thrombectomy (MT). Despite continuous advancements in MT technology and techniques, reperfusion failure still occurs in ≈15% to 30% of patients with large vessel occlusion strokes undergoing MT. We aim to evaluate the safety and efficacy of rescue intracranial stenting for large vessel occlusion stroke after failed MT.

METHODS:

The SAINT (Stenting and Angioplasty in Neurothrombectomy) Study is a retrospective analysis of prospectively collected data from 14 comprehensive stroke centers through January 2015 to December 2020. Patients were included if they had anterior circulation large vessel occlusion stroke due to intracranial internal carotid artery and middle cerebral artery-M1/M2 segments and failed MT. The cohort was divided into 2 groups: rescue intracranial stenting and failed recanalization (modified Thrombolysis in Cerebral Ischemia score 0–1). Propensity score matching was used to balance the 2 groups. The primary outcome was the shift in the degree of disability as measured by the modified Rankin Scale at 90 days. Secondary outcomes included functional independence (90-day modified Rankin Scale score 0–2). Safety measures included symptomatic intracranial hemorrhage and 90-day mortality.

RESULTS:

A total of 499 patients were included in the analysis. Compared with the failed reperfusion group, rescue intracranial stenting had a favorable shift in the overall modified Rankin Scale score distribution (acOR, 2.31 [95% CI, 1.61–3.32]; P <0.001), higher rates of functional independence (35.1% versus 7%; adjusted odds ratio [aOR], 6.33 [95% CI, 3.14–12.76]; P <0.001), and lower mortality (28% versus 46.5%; aOR, 0.55 [95% CI, 0.31–0.96]; P =0.04) at 90 days. Rates of symptomatic intracerebral hemorrhage were comparable across both groups (7.1% versus 10.2%; aOR, 0.99 [95% CI, 0.42–2.34]; P =0.98). The matched cohort analysis demonstrated similar results. Specifically, rescue intracranial stenting (n=107) had a favorable shift in the overall modified Rankin Scale score distribution (acOR, 3.74 [95% CI, 2.16–6.57]; P <0.001), higher rates of functional independence (34.6% versus 6.5%; aOR, 10.91 [95% CI, 4.11–28.92]; P <0.001), and lower mortality (29.9% versus 43%; aOR, 0.49 [95% CI, 0.25–0.94]; P =0.03) at 90 days with similar rates of symptomatic intracerebral hemorrhage (7.5% versus 11.2%; aOR, 0.87 [95% CI, 0.31–2.42]; P =0.79) compared with patients who failed to reperfuse (n=107). There was no heterogeneity of treatment effect across the prespecified subgroups for improvement in functional outcomes.

CONCLUSIONS:

Acute intracranial stenting appears to be a safe and effective rescue strategy in patients with large vessel occlusion stroke who failed MT. Randomized multicenter trials are warranted.

Predictors of First-Pass Effect in Endovascular Thrombectomy With Stent-Retriever Devices for Acute Large Vessel Occlusion Stroke

Background and Purpose

Successful recanalization after the first pass of the device in endovascular thrombectomy (EVT) can significantly improve patients' prognosis. We aimed to investigate the possible factors that influence achieving the first-pass effect (FPE).

Methods

We retrospectively analyzed the patients who underwent EVT caused by anterior circulation large vessel occlusion stroke (ALVOS) in our center. The FPE was defined as a successful recanalization [modified Thrombolysis in Cerebral Infarction (mTICI) 2b/3 defined as modified FPE (mFPE); mTICI 3 as true FPE (tFPE)] after one pass of the device without rescue therapy. Univariate and multivariate regression analyses were used to explore the predictors of FPE and the relationship between FPE and prognosis.

Results

There were 278 patients (age, 69.3 ± 10.9 years, male, 51.1%) included, 30.2% of them achieved mFPE, while 21.2% achieved tFPE. We found the higher clot burden score (CBS), the truncal-type occlusion, and the favorable anatomy of both extracranial and intracranial segments of the internal carotid artery (ICA) were associated with achieving mFPE. The higher CBS and truncal-type occlusion were statistically significant predictors of tFPE. Moreover, FPE was significantly associated with improved clinical outcomes, regardless of mFPE and tFPE.

Conclusions

The CBS, tortuosity of ICA, and angiographic occlusion type were independent predictors of achieving FPE. The rate of improved clinical and safety outcomes was higher in patients with FPE, which has important clinical significance.

Transcarotid Access for Mechanical Thrombectomy in Acute Ischemic Stroke: A Meta-Analysis and Systematic Review

OBJECTIVES

Despite the success of mechanical thrombectomy in large vessel acute ischemic stroke, recanalization may fail due to difficult anatomic access or peripheral arterial occlusive disease. In these cases, transcarotid access may be used as an alternative, but it has not gained prominence due to safety concerns. Our objective was to assess the efficacy and safety of transcarotid access for mechanical thrombectomy.

MATERIALS AND METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to perform a systematic review with articles published from 2010 to 2020 summarizing pre-intervention characteristics, techniques utilized, and outcomes of patients undergoing mechanical thrombectomy via trans-carotid puncture. We performed a meta-analysis of clinical outcomes, reperfusion times and overall complications rates of trans-carotid approach.

RESULTS

Six studies describing 80 total attempts at carotid access, 72 of which were successful (90% success rate), were included. Direct carotid puncture was most often used as a rescue technique (87% of patients) secondary to failed femoral access. Successful recanalization was achieved in 76% of patients. 90 day modified Rankin Scale ≤ 2 was achieved in 28% of patients. Carotid puncture-reperfusion time was 32 min (CI = 24-40, p < 0.001). Cervical complications occurred at a rate of 26.5% (95% CI = 17%-38%). Only 1.3% (1/80 patients) had a fatal outcome and 96% of complications required no intervention.

CONCLUSIONS

Our results on the safety and efficacy of transcarotid access suggests that this approach is a viable alternative to failed thrombectomy when transfemoral or trans-radial access may be impractical.

Association between CHADS2, CHA2DS2-VASc, ATRIA, and Essen Stroke Risk Scores and Unsuccessful Recanalization after Endovascular Thrombectomy in Acute Ischemic Stroke Patients

Background: The CHADS₂, CHA₂DS₂-VASc, ATRIA, and Essen scores have been developed for predicting vascular outcomes in stroke patients. We investigated the association between these stroke risk scores and unsuccessful recanalization after endovascular thrombectomy (EVT). Methods: From the nationwide multicenter registry (Selection Criteria in Endovascular Thrombectomy and Thrombolytic therapy (SECRET)) (Clinicaltrials.gov NCT02964052), we consecutively included 501 patients who underwent EVT. We identified pre-admission stroke risk scores in each included patient. Results: Among 501 patients who underwent EVT, 410 (81.8%) patients achieved successful recanalization (mTICI ≥ 2b). Adjusting for body mass index and p < 0.1 in univariable analysis revealed the association between all stroke risk scores and unsuccessful recanalization (CHADS₂ score: odds ratio (OR) 1.551, 95% confidence interval (CI) 1.198–2.009, p = 0.001; CHA₂DS₂VASc score: OR 1.269, 95% CI 1.080–1.492, p = 0.004; ATRIA score: OR 1.089, 95% CI 1.011–1.174, p = 0.024; and Essen score: OR 1.469, 95% CI 1.167–1.849, p = 0.001). The CHADS₂ score had the highest AUC value and differed significantly only from the Essen score (AUC of CHADS₂ score; 0.618, 95% CI 0.554–0.681). Conclusion: All stroke risk scores were associated with unsuccessful recanalization after EVT. Our study suggests that these stroke risk scores could be used to predict recanalization in stroke patients undergoing EVT.

Higher baseline blood glucose is associated with reduced likelihood for successful recanalization in patients with basilar artery occlusion

Purpose

Evidence regarding the effect of mechanical thrombectomy (MT) of basilar artery occlusion (BAO) stroke is yet sparse. As successful recanalization has been suggested as major determinant of outcome, the early identification of modifiable factors associated with successful recanalization could be of importance to improve functional outcome. Hyperglycemia has been associated with enhanced thrombin generation and unfavorably altered clot features.

Objective

We hypothesized that serum baseline glucose is associated with likelihood of vessel recanalization mediated by collateral quality and clot burden in BAO stroke.

Methods

BAO stroke patients who received multimodal CT on admission were analyzed. The association of vessel recanalization defined using modified Thrombolysis in cerebral infarction scale (mTICI) scores 2b-3, and baseline imaging and clinical parameters were tested in logistic regression analyses. Collateral quality and clot burden were evaluated using the Basilar Artery on CT-Angiography (BATMAN) score.

Results

Out of 117 BAO patients, 91 patients (78%) underwent MT. In 70 patients (77%), successful recanalization could be achieved (mTICI 2b/3). In multivariable logistic regression analysis, only a higher BGL (aOR 0.97, 95% CI 0.96–0.99, p = 0.03) and higher BATMAN score (aOR 1.77, 95% CI 1.11–2.82, p = 0.02) were independently associated with vessel recanalization. Application of alteplase, or time from symptom onset-imaging revealed no independent association with recanalization status.

Conclusion

Higher BGL was significantly associated with reduced likelihood for recanalization success besides BATMAN score as a measure of collateral quality and clot burden. BGL could be tested as a modifiable parameter to increase likelihood for recanalization in BAO stroke, aiming to improve functional outcome.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-021-10948-1.

Carotid artery direct access for mechanical thrombectomy: the Carotid Artery Puncture Evaluation (CARE) study

BACKGROUND

In acute ischemic stroke due to anterior large vessel occlusion (AIS-LVO), accessing the target occluded vessel for mechanical thrombectomy (MT) is sometimes impossible through the femoral approach. We aimed to evaluate the safety and efficacy of direct carotid artery puncture (DCP) for MT in patients with failed alternative vascular access.

METHODS

We retrospectively analyzed data from 45 stroke centers in France, Switzerland and Germany through two research networks from January 2015 to July 2019. We collected physician-centered data on DCP practices and baseline characteristics, procedural variables and clinical outcome after DCP. Uni- and multivariable models were conducted to assess risk factors for complications.

RESULTS

From January 2015 to July 2019, 28 149 MT were performed, of which 108 (0.39%) resulted in DCP due to unsuccessful vascular access. After DCP, 77 patients (71.3%) had successful reperfusion (modified Thrombolysis In Cerebral Infarction (mTICI) score ≥2b) and 28 (25.9%) were independent (modified Rankin Scale (mRS) score 0-2) at 3 months. 20 complications (18.5%) attributed to DCP occurred, all of them during or within 1 hour of the procedure. Complications led to extension of the intubation time in the intensive care unit in 7 patients (6.4%) and resulted in death in 3 (2.8%). The absence of use of a hemostatic closure device was associated with a higher complication risk (OR 3.04, 95% CI 1.03 to 8.97; p=0043).

CONCLUSION

In this large multicentric study, DCP was scantly performed for vascular access to perform MT (0.39%) in patients with AIS-LVO and had a high rate of complications (18.5%). Our results provide arguments for not closing the cervical access by manual compression after MT.

The Q and A-The MIVI Q Catheters for Aspiration Thrombectomy-Initial Experience from London

Background: Aspiration thrombectomy is a widely accepted treatment option for large vessel occlusion (LVO). The MIVI aspiration system has a novel design to maximize the lumen size. We present the results of our initial experience with this innovative aspiration thrombectomy system. Materials and Methods: Retrospectively, we reviewed our database to find all cases of LVO treated with the MIVI Q system (February 2019 and July 2020). In addition, we recorded the baseline demographics, NIHSS, ASPECT, mTICI scores, procedural time, complications, and 90 day mRS. Results: Herein, we identified 25 patients with an average age of 65.3 ± 19.3 years (range 19–89), majority of whom were female (n = 14, 56%). The average NIHSS was 16.9 ± 6.7 (range 6–30), and the average CT ASPECT was 7.9 ± 1.4 (range 5–10). The most common clot location was the M1 segment of the MCA (n = 16, 64%). Four of the patients had tandem lesions (16%). The average clot length was 21.7 ± 31 mm (range 2–130 mm). Of the 23 cases where the Q catheter reached the proximal clot face, mTICI ≥ 2b was achieved on the first pass in 11 cases (44%), and at the end of the ‘Q aspiration’ only the procedures with 16 patients achieved mTICI ≥ 2b recanalization (64%). Stent-retrievers were used in 13 cases (52%). At the end of the procedure, 24 patients (96%) achieved mTICI ≥ 2b with 18 patients (72%) achieving mTICI ≥ 2c. The average number of passes with the Q catheter, including when it was used for SOLUMBRA, was 2.1 ± 2.2 (range 1–10). The mean procedure time was 69 ± 32 mins (range 7–116 mins). No complications were associated with the MIVI Q. Conclusions: The MIVI aspiration system is a novel technology with regards to aspiration mechanical thrombectomy. The system is easy to use with early results comparable to other large-bore catheter systems. However, further studies are needed.

Statistical shape model of vessel centerline for endovascular paths comparison in mechanical thrombectomy

Endovascular interventions are experiencing an important development. Despite many advantages of this type of intervention, catheter navigation is still a cause of difficulties or failure. Mechanical thrombectomy is one of these interventions where navigation difficulties are related to the ability to navigate the aortic arch and access the carotid. These difficulties are due to the selection of adequate catheters and guides for a specific anatomy and to the technical gesture to operate. The objective of this work is to propose a method to find similar endovascular navigation paths from pre-existing patients to support intervention in mechanical thrombectomy. For each patient, iso-centerlines of the aortic arch and supra-aortic trunks are extracted from pre-operative magnetic resonance angiography volume. A statistical shape model is computed from these vascular structure iso-centerlines. Euclidean distance between vectors of statistical shape model modes is used to compare endovascular navigation paths. A set of 6 patient cases was used to compute the statistical shape model. For validation, an additional set of 5 patient cases was considered to generate new iso-centerlines.Retrieval of closest iso-centerlines were correct in more than 95% of cases with the proposed method while this percentage goes down to 43% with Euclidean distance between 3D points of iso-centerlines.Clinical relevance-The presented method allows physicians to retrieve past navigation paths similar to a new one. Used in planning, this could allow to anticipate navigation difficulties in mechanical thrombectomy.

Systematic Review on Endovascular Access to Intracranial Arteries for Mechanical Thrombectomy in Acute Ischemic Stroke

PURPOSE

In acute ischemic stroke for large vessel occlusions, delayed or failed access to intracranial occlusions has a negative impact on procedural and clinical outcomes. The aim of this review is to identify and quantify access failures and challenges in mechanical thrombectomy.

METHODS

A systematic literature review of PubMed and Scopus databases from January 2014 to October 2020 was performed. Articles reporting consecutive patients were used to calculate a crude failure rate of femoral and alternative accesses.

RESULTS

A total of 50 articles met the inclusion criteria, totalling 12,838 interventions. Failure to access the occlusion through transfemoral access occurred in 4.4% of patients, most commonly due to challenging supra-aortic vessel anatomy, decreasing to 3.6% when all alternative access routes were attempted. Failed access from alternative routes (direct carotid, radial and brachial approaches) attempted first-line or after failed femoral attempt were reported in 7.3% of patients. The occurrence rate of potentially challenging features (anatomical, diseases or others) ranged from 4.7% to 47.4%, primarily impacting the access time, procedure time, recanalization and clinical outcomes.

CONCLUSION

Failure to access the occlusion is a significant contributor to failed recanalization, regardless of access routes. Challenging, but eventually successful access is also a relevant factor in procedural and clinical outcomes; however challenging access requires a universal definition to enable quantification, so that methods for procedural optimization can be critically assessed.

Preclinical testing platforms for mechanical thrombectomy in stroke: a review on phantoms, in-vivo animal, and cadaveric models

Preclinical testing platforms have been instrumental in the research and development of thrombectomy devices. However, there is no single model which fully captures the complexity of cerebrovascular anatomy, physiology, and the dynamic artery-clot-device interaction. This article provides a critical review of phantoms, in-vivo animal, and human cadaveric models used for thrombectomy testing and provides insights into the strengths and limitations of each platform. Articles published in the past 10 years that reported thrombectomy testing platforms were identified. Characteristics of each test platform, such as intracranial anatomy, artery tortuosity, vessel friction, flow conditions, device-vessel interaction, and visualization, were captured and benchmarked against human cerebral vessels involved in large-vessel occlusion stroke. Thrombectomy phantoms have been constructed from silicone, direct 3D-printed polymers, and glass. These phantoms represent oversimplified patient-specific cerebrovascular geometry but enable adequate visualization of devices and clots under appropriate flow conditions. They do not realistically mimic the artery-clot interaction. For the animal models, arteries from swine, canines, and rabbits have been reported. These models can reasonably replicate the artery-clot-device interaction and have the unique value of evaluating the safety of thrombectomy devices. However, the vasculature geometries are substantially less complex and flow conditions are different from human cerebral arteries. Cadaveric models are the most accurate vascular representations but with limited access and challenges in reproducibility of testing conditions. Multiple test platforms should be likely used for comprehensive evaluation of thrombectomy devices. Interpretation of the testing results should take into consideration platform-specific limitations.

Circulating Cytokines and Growth Factors in Acute Cerebral Large Vessel Occlusion-Association with Success of Endovascular Treatment

Mechanical thrombectomy (MT) is a highly efficient treatment in patients with acute ischemic stroke due to large vessel occlusion (LVO). However, in a relevant proportion of LVO, no sufficient recanalization can be achieved. The composition of cerebral thrombi is highly heterogeneous and may constitute a relevant factor for insufficient reperfusion. We hypothesized that circulating cytokines and growth factors involved in thromboinflammation and platelet activation may be associated with reperfusion status and thrombus composition in patients undergoing MT. An according biomarker panel was measured in plasma specimens taken prior to MT and at a 7-day follow-up. The reperfusion status was categorized into sufficient or insufficient. The composition of retrieved thrombi was histologically analyzed. Differences of baseline biomarker concentrations between insufficient and sufficient reperfusions were highest for interferon (IFN)-γ, epidermal growth factor, platelet-derived growth factor (PDGF)-AB/BB, and IFN-γ-induced protein 10 (IP-10/CXCL10). After applying correction for multiple comparisons and logistic regression analysis adjusting for stroke etiology, intravenous thrombolysis, and vascular risk factors, PDGF-AB/BB was identified as an independent predictor of reperfusion status (odds ratio: 0.403; 95% confidence interval: 0.199-0.819). Histological analysis revealed that the majority of thrombi had a mixed composition. In conclusion, this study provides the first evidence that cytokines and growth factors are potential effectors in patients undergoing MT for the treatment of acute ischemic stroke.

The Columbus steerable guidewire in neurointerventions: early clinical experience and applications

Objective

To report our early experience in using the steerable ‘Columbus’ guidewire, also known as ‘Drivewire’ in the USA, and its potential applications in neurovascular interventions.

Methods

Neurointerventions in 36 patients (20 female, 16 male) using the steerable Columbus guidewire were recorded from August 2019 to December 2020 and included a variety of neurovascular procedures: Treatment of aneurysms (n=17), thrombectomy in acute ischemic stroke (n=12), and others (n=7), such as treatment of stenosis and embolization procedures. Immediate follow-up with digital subtraction angiography and tracking of each patient’s clinical outcome was performed.

Results

In 35 out of 36 cases, the target vessel was reached with Columbus, including advancement of the appropriate microcatheter. In 14 cases, additional wires were used, mainly because of the nature of the procedures (eg, use of multiple wires/buddy wires or exchange maneuvers). In five cases, the Columbus wire was damaged by the operator and had to be replaced. Peri-interventional complications occurred in two patients, neither attributed to the Columbus guidewire.

Conclusions

The new Columbus neurovascular guidewire has the unique ability to be shaped within the patient. Currently available versions lack torquability compared with other available guidewires but offer tremendous support at the tip, allowing maneuvers which are impossible with other wires on the market.

Vascular tortuosity in endovascular mechanical thrombectomy

Endovascular mechanical thrombectomy effectively removes occlusive thrombi from the arterial lumen; however, there is little literature supporting the relevance of vascular geometry on surgical outcomes. Critical vessel characteristics including the degree of angulation and tortuosity influence the ability to advance stent retriever devices toward the site of occlusion. Therefore, it is crucial to evaluate the impact of carotid artery catheter pathway accessibility on the thrombectomy outcomes in acute ischemic stroke (AIS) patients. Traditional imaging modalities generate incomplete pictures of the vascular tortuosity and are prone to clinical judgment errors. Recent three-dimensional computed tomography angiography image analysis techniques circumvent these limitations to calculate accurate tortuosity and angulation measurements. These novel images facilitate classifying common anatomical variant patients into groups that may be treated with specially designed catheter devices. Importantly, this image analysis method reveals significant angulation in the common carotid artery and extracranial internal carotid artery that correlates with delays in reaching the occlusion site. Increased age, which is associated with increased risk of stroke, also increases the incidence of severe tortuosity. The semi-automated measurements technique also demonstrate that full 360° arterial loops are present in nearly 3% of catheter pathways and that the overall degree of angulation differs bilaterally. In this review, we examine the utility of this novel image analysis procedure and evaluate the recent literature relevant to neuroendovascular thrombectomy in AIS patients. Three literature databases – PubMed, Embase, and Web of Science were queried for original articles investigating both preclinical and clinical thrombectomy applications.

Inter-facility transfer for patients with acute large vessel occlusion stroke receiving mechanical thrombectomy

BACKGROUND

Mechanical thrombectomy (MT) is the preferred treatment for large vessel occlusion (LVO) ischemic stroke, and neurological outcome improves with earlier treatment. Patients with LVO frequently require inter-facility transfer to access MT but delays at transferring EDs may worsen neurological outcomes.

METHODS

We conducted a retrospective observational study to evaluate the association of time spent and transferring EDs with 90-day neurological outcomes among patients who were transferred from an outside ED to the Comprehensive Stroke Center and received MT. Time intervals at transferring EDs were examined descriptively, and multivariable logistic regression modeling was used to examine the association of time spent in the ED with 90-day neurologic outcome (modified Rankin Scale; good ≤2, poor ≥3).

RESULTS

Among 111 patients transferred to a stroke center for MT between 2013 and 2017, the time between CT scan and the stroke center transfer request was 44 (IQR 27,65) minutes, or 47% of transferring ED total duration. Duration at the transferring ED was not significantly associated with 90-day outcome. Only NIH Stroke Scale at the time of arrival to the stroke center was associated with good 90-day neurological outcome (aOR 0.84, 95%CI 0.77, 0.92, p < 0.0001).

CONCLUSIONS

Among LVO patients transferred for MT, the total time spent at transferring EDs was not associated with 90-day neurologic outcome in patients with LVO. As therapies and their associated effectiveness improves over time, future investigations should further characterize the time between CT and transfer request to identify targets for process improvement and clinical outcomes.

Optimizing Patient Selection for Interhospital Transfer and Endovascular Therapy in Acute Ischemic Stroke: Real-World Data From a Supraregional, Hub-and-Spoke Neurovascular Network in Germany

Background: Interhospital transfer for endovascular treatment (EVT) within neurovascular networks might result in transfer of patients who will not undergo EVT (futile transfer). Limited evidence exists on factors associated with the primary patient selection for interhospital transfer from primary stroke centers (PSCs) to comprehensive stroke centers (CSCs), or EVT-workflow parameters that may render a transfer futile.

Methods: A prospective, registry-based study was performed between July 1, 2017 and June 30, 2018, at a hub-and-spoke neurovascular network in southwest Germany, comprising 12 referring PSCs and one designated CSC providing round-the-clock EVT at the University Hospital Tübingen. Patients with acute ischemic stroke due to suspected large artery occlusion (LAO) were included upon emergency interhospital transfer inquiry (ITI).

Results: ITI was made for 154 patients, 91 (59%) of whom were transferred to the CSC. Non-transferred patients (41%) had significantly higher premorbid modified Rankin scale scores (mRS) compared to transferred patients [median (IQR): 2 (1–3) vs. 0 (0–1), p < 0.001]. Interhospital transfer was denied due to: distal vessel occlusion (44.4%), or non-verifiable LAO (33.3%) in computed tomography angiography (CTA) upon teleconsultation by CSC neuroradiologists; limited Stroke-Unit or ventilation capacity (9.5%), or limited neuroradiological capacity at the CSC (12.7%). The CT-to-ITI interval was significantly longer in patients denied interhospital transfer [median (IQR): 43 (29–56) min] compared to transferred patients [29 (15–55), p = 0.029]. No further differences in EVT-workflow, and no differences in the 3-month mRS outcomes were noted between non-transferred and transferred patients [median (IQR): 2 (0–5) vs. 3 (1–4), p = 0.189]. After transfer to the CSC, 44 (48%) patients underwent EVT. The Alberta stroke program early CT score [ORadj (95% CI): 1.786 (1.573–2.028), p < 0.001] and the CT-to-ITI interval [0.994 (0.991–0.998), p = 0.001] were significant predictors of the likelihood of EVT performance.

Conclusion: Our findings show that hub-and-spoke neurovascular network infrastructures efficiently enable access to EVT to patients with AIS due to LAO, who are primarily admitted to PSCs without on-site EVT availability. As in real-world settings optimal allocation of EVT resources is warranted, teleconsultation by experienced endovascular interventionists and prompt interhospital-transfer-inquiries are crucial to reduce the futile transfer rates and optimize patient selection for EVT within neurovascular networks.

Vessel diameter and catheter-to-vessel ratio affect the success rate of clot aspiration

BACKGROUND

A direct aspiration first pass technique (ADAPT) is an efficient, safe, cost-effective, and fast thrombectomy technique.

OBJECTIVE

To evaluate anatomical and clot characteristics associated with success of the aspiration component as part of ADAPT.

METHODS

106 cases of acute carotid-T, basilar, and middle cerebral artery occlusion undergoing endovascular treatment with ADAPT were retrospectively assessed for successful catheter-clot contact and successful primary aspiration, defined as a Thrombolysis in Cerebral Infarction score ≥2b after primary aspiration with 5F or 6F aspiration catheters. Patient age, National Institutes of Health Stroke Scale (NIHSS) score, time from symptom onset to groin puncture, time from groin puncture to revascularization, aortic arch type, access vessel tortuosity, vessel diameter at the proximal end of the thrombus, catheter-to-vessel ratio (CVR), clot density, length, and perviousness were determined.

RESULTS

Successful clot contact with the aspiration catheter was achieved in 76 cases (72%); these patients were younger (67.7±15.2 vs 73.7±11.4 years; p=0.05) and had less tortuous access vessels (1 vs 2 reverse curves; p=0.004) than those in whom clot contact failed. Successful primary aspiration occurred in 36 of these cases (47%) and was associated with significantly smaller vessel diameter at the proximal thrombus end (2.5±0.7 mm vs 3.1±1.3 mm; p=0.01) and higher CVR (CVR outer diameter: 0.85±0.2 vs 0.68±0.2; p=0.01 and CVR inner diameter: 0.72±0.2 vs 0.58±0.2; p<0.001). No significant differences were seen in aortic arch type, radiographic clot features, and NIHSS score.

CONCLUSION

With ADAPT, patient age and vessel tortuosity affect the ability to deliver the aspiration catheter and achieve clot contact, whereas vessel diameter and CVR at the aspiration site seem to affect the effectiveness of clot aspiration. Strategies aimed at improving catheter deliverability and increasing CVR may increase the efficacy of ADAPT.