Mechanical Thrombectomy-A Brief Review of a Revolutionary new Treatment for Thromboembolic Stroke

Hypothermia is Associated with Improved Neurological Outcomes After Mechanical Thrombectomy

BACKGROUND

Acute ischemic stroke (AIS) is the second leading cause of death globally. Mechanical thrombectomy (MT) has improved patient prognosis but expedient treatment is still necessary to minimize anoxic injury. Lower intraoperative body temperature decreases cerebral oxygen demand, but the role of hypothermia in treatment of AIS with MT is unclear.

METHODS

We retrospectively reviewed patients undergoing MT for AIS from 2014 to 2020 at our institution. Patient demographics, comorbidities, intraoperative parameters, and outcomes were collected. Maximum body temperature was extracted from minute-by-minute anesthesia readings, and patients with maximal temperature below 36°C were considered hypothermic. Risk factors were assessed by χ2 and multivariate ordinal regression.

RESULTS

Of 68 patients, 27 (40%) were hypothermic. There was no significant association of hypothermia with patient age, comorbidities, time since last known well, number of passes intraoperatively, favorable revascularization, tissue plasminogen activator use, and immediate postoperative complications. Hypothermic patients exhibited better neurologic outcome at 3-month follow-up (P = 0.02). On multivariate ordinal regression, lower maximum intraoperative body temperature was associated with improved 3-month outcomes (P < 0.001), when adjusting for other factors influencing neurological outcomes. Other significant protective factors included younger age (P = 0.03), better revascularization (P = 0.03), and conscious sedation (P = 0.02).

CONCLUSIONS

Lower intraoperative body temperature during MT was independently associated with improved neurological outcome in this single center retrospective series. These results may help guide clinicians in employing therapeutic hypothermia during MT to improve long-term neurologic outcomes from AIS, although larger studies are needed.

Transauricular nerve stimulation in acute ischaemic stroke requiring mechanical thrombectomy: Protocol for a phase 2A, proof-of-concept, sham-controlled randomised trial

BACKGROUND

Labile blood pressure after acute ischaemic stroke requiring mechanical thrombectomy is independently associated with poor patient outcomes.

OBJECTIVES

This study protocol describes is designed to determine whether transauricular nerve stimulation, improves baroreflex sensitivity, reduces blood pressure variability in the first 24 hours after acute ischaemic stroke requiring mechanical thrombectomy.

DESIGN: PHASE 2A, PROOF-OF-CONCEPT, SHAM-CONTROLLED RANDOMISED TRIAL

Methods and Analysis: 36 individuals undergoing mechanical thrombectomy for acute ischaemic stroke with established hypertension aged >18 years will be randomly allocated to receive bilateral active or sham transauricular nerve stimulation for the duration of the mechanical thrombectomy procedure (AffeX-CT/001 investigational device). The intervention will be repeated for 1h the morning following the mechanical thrombectomy. Non-invasive blood pressure will be measured ≥2h for 24h after mechanical thrombectomy. Holter electrocardiographic monitoring will be recorded during transauricular nerve stimulation. Participants, clinicians and investigators will be masked to treatment allocations. The primary outcome will be the coefficient of variation of systolic blood pressure. Secondary outcomes include additional estimates of blood pressure variability and time/frequency-domain measures of autonomic cardiac modulation An adjusted sample size of 36 patients is required to have a 90% chance of detecting, as significant at the 5% level, a difference in the coefficient of variation in systolic blood pressure of 5±4mmHg between sham and active stimulation [assuming 5% non-compliance rate in each group]. Ethics: confirmed on 16 March 2023 by HRA and Health and Care Research Wales ethics committee (reference 23/WA/0013).

DISCUSSION

This study will provide proof-of-concept data that examines whether non-invasive autonomic neuromodulation can be used to favourably modify blood pressure and autonomic control after acute ischaemic stroke requiring mechanical thrombectomy.

TRIAL REGISTRATION

Trial registration number: NCT05417009.

Angiographic tapering sign as a surrogate marker for large vessel occlusion due to intracranial atherosclerotic stenosis and its clinical implication: a retrospective matched case-control study

BACKGROUND

The purpose of this study was to investigate whether the initial DSA appearance of the occlusion during mechanical thrombectomy (MT) can help distinguish the nature of the underlying lesion and predict radiological and clinical outcomes.

METHODS

We retrospectively reviewed cases of patients with acute ischemic stroke who underwent MT for anterior circulation occlusion between March 2017 and February 2020. Underlying intracranial atherosclerotic stenosis (ICAS) was determined based on the presence of fixed stenosis after endovascular treatment. Patients were categorized based on the appearance of the occlusion observed in the initial DSA as tapering sign (+) or (-) groups. We performed 1:2 propensity score matching to establish a proper control group among the tapering sign (-) group. We analyzed and compared baseline characteristics and clinical outcomes between the two groups.

RESULTS

A total of 293 patients (tapering sign (+), n=47; tapering sign (-), n=246) were included in the analysis. The procedure time of MT was significantly longer for the tapering sign (+) group, and the successful recanalization rate after MT was significantly lower in the tapering sign (+) group than in the tapering sign (-) group. Logistic regression showed that ICAS-related occlusion was strongly associated with a positive angiographic tapering sign, and the angiographic tapering sign was a negative factor for the first-pass effect during MT. However, a 3-month good functional outcome was not significantly associated with the angiographic tapering sign.

CONCLUSIONS

The tapering sign on the initial DSA could be a surrogate marker for ICAS-related occlusion and procedural difficulty. However, its clinical significance remains unclear.

Real-time tracking of fibrinolysis under constant wall shear and various pulsatile flows in an in-vitro thrombolysis model

A great need exists for the development of a more representative in-vitro model to efficiently screen novel thrombolytic therapies. We herein report the design, validation, and characterization of a highly reproducible, physiological scale, flowing clot lysis platform with real-time fibrinolysis monitoring to screen thrombolytic drugs utilizing a fluorescein isothiocyanate (FITC)-labeled clot analog. Using this Real-Time Fluorometric Flowing Fibrinolysis assay (RT-FluFF assay), a tPa-dependent degree of thrombolysis was observed both via clot mass loss as well as fluorometrically monitored release of FITC-labeled fibrin degradation products. Percent clot mass loss ranged from 33.6% to 85.9% with fluorescence release rates of 0.53 to 1.17 RFU/min in 40 and 1000 ng/mL tPa conditions, respectively. The platform is easily adapted to produce pulsatile flows. Hemodynamics of human main pulmonary artery were mimicked through matching dimensionless flow parameters calculated using clinical data. Increasing pressure amplitude range (4-40 mmHg) results in a 20% increase of fibrinolysis at 1000 ng/mL tPA. Increasing shear flow rate (205-913 s^-1) significantly increases fibrinolysis and mechanical digestion. These findings suggest pulsatile level affects thrombolytic drug activities and the proposed in-vitro clot model offers a versatile testing platform for thrombolytic drug screening.

Common Data Elements Reported in Mechanical Thrombectomy for Acute Ischemic Stroke: A Systematic Review of Active Clinical Trials

BACKGROUND

New trials are planned regularly to provide the highest quality of evidence and invade new occlusion territories, which requires a pre-defined reporting strategy with consistent, common data elements for more straightforward collective evidence synthesis. We sought to review all active endovascular thrombectomy trials to investigate their patient selection criteria, intervention description, and reported outcomes.

METHODS

A literature search was systematically conducted on clinicaltrials.gov for active trials and all intervention, inclusion criteria, and outcomes reported were extracted. A qualitative synthesis of the frequency of study design types and data elements are graphically and narratively presented.

RESULTS

A total of 32 studies were tagged and included in the final qualitative analysis. The inclusion criteria were highly variable, including different cut-offs for the last well-known baseline National Institutes of Health Stroke Scale, Alberta Stroke Program Early CT Score, and modified Rankin scale (mRS). Half of the studies (16/32) mentioned "thrombectomy" without defining which technique or device was used, and the final thrombolysis in cerebral infarction scale was provided in 19 (59.4%) studies. Heterogeneity was also present among the studies reporting a first-pass effect, both in how studies defined the outcome and in used ranges for mRS. Mortality and intracerebral hemorrhage (ICH) were more homogenous in their presentation and follow-up.

CONCLUSIONS

There is a great degree of heterogeneity in the active thrombectomy trials concerning inclusion criteria, interventions used, and how outcomes are being reported.

REACT Aspiration Catheters: Clinical Experience and Technical Considerations

Aspiration catheters are widely used in mechanical thrombectomy procedures to treat acute ischemic stroke due to large vessel occlusion. The key performance requirements for aspiration catheters are ease of navigation and effective aspiration. In this work, we review the clinical experience and in vitro studies of REACT aspiration catheters (Medtronic, Minneapolis, MN, USA). In vitro experiments showed that REACT catheters exhibit solid performance in navigation and aspiration. Previous studies reported that the recanalization capacity of the aspiration catheters can be influenced by the devices’ inner diameter and tip distensibility, the catheter-to-vessel diameter ratio, the negative pressure delivered by the vacuum generator, the cyclical aspiration mode, the proximal flow arrest, and the angle of interaction between catheter and clot. REACT catheters can be navigated through the vasculature without any support from a microcatheter/ microwire in favorable anatomical configurations. In challenging situations, mostly encountered when crossing the ophthalmic segment of the internal carotid artery, the use of the stentriever anchoring technique or delivery assist catheter can facilitate the navigation. Three clinical studies reporting on 299 patients who underwent mechanical thrombectomy with REACT catheters were included in this review. Successful recanalization (modified treatment in cerebral ischemia score 2b–3) was achieved in 89–96% of cases, no procedural complications related to REACT catheters were reported, and functional independence (modified Rankin Scale 0–2) at 90-days was 24–36%. In vitro experimental evaluations and clinical studies support the safety and effectiveness of the REACT catheters.

Trackability of distal access catheters: an in vitro quantitative evaluation of navigation strategies

BACKGROUND

In mechanical thrombectomy (MT), distal access catheters (DACs) are tracked through the vascular anatomy to reach the occlusion site. The inability of DACs to reach the occlusion site has been reported as a predictor of unsuccessful recanalization. This study aims to provide insight into how to navigate devices through the vascular anatomy with minimal track forces, since higher forces may imply more risk of vascular injuries.

METHODS

We designed an experimental setup to monitor DAC track forces when navigating through an in vitro anatomical model. Experiments were recorded to study mechanical behaviors such as tension buildup against vessel walls, DAC buckling, and abrupt advancements. A multiple regression analysis was performed to predict track forces from the catheters' design specifications.

RESULTS

DACs were successfully delivered to the target M1 in 60 of 63 in vitro experiments (95.2%). Compared to navigation with unsupported DAC, the concomitant coaxial use of a microcatheter/microguidewire and microcatheter/stent retriever anchoring significantly reduced the track forces by about 63% and 77%, respectively (p<0.01). The presence of the braid pattern in the reinforcement significantly reduced the track forces regardless of the technique used (p<0.05). Combined coil and braid reinforcement configuration, as compared with coil alone, and a thinner distal wall were predictors of lower track force when navigating with unsupported DAC.

CONCLUSIONS

The use of microcatheter and stent retriever facilitate smooth navigation of DACs through the vascular tortuosity to reach the occlusion site, which in turn improves the reliability of tracking when positioning the DAC closer to the thrombus interface.

Effect of Intravenous Alteplase on Functional Outcome and Secondary Injury Volumes in Stroke Patients with Complete Endovascular Recanalization

Intravenous thrombolytic therapy with alteplase (IVT) is a standard of care in ischemic stroke, while recent trials investigating direct endovascular thrombectomy (EVT) approaches showed conflicting results. Yet, the effect of IVT on secondary injury volumes in patients with complete recanalization has not been analyzed. We hypothesized that IVT is associated with worse functional outcome and aggravated secondary injury volumes when administered to patients who subsequently attained complete reperfusion after EVT. Anterior circulation ischemic stroke patients with complete reperfusion after thrombectomy defined as thrombolysis in cerebral infarctions (TICI) scale 3 after thrombectomy admitted between January 2013–January 2021 were analyzed. Primary endpoints were the proportion of patients with functional independence defined as modified Rankin Scale (mRS) score 0–2 at day 90, and secondary injury volumes: Edema volume in follow-up imaging measured using quantitative net water uptake (NWU), and the rate of symptomatic intracerebral hemorrhage (sICH). A total of 219 patients were included and 128 (58%) patients received bridging IVT before thrombectomy. The proportion of patients with functional independence was 28% for patients with bridging IVT, and 34% for patients with direct thrombectomy (p = 0.35). The rate of sICH was significantly higher after bridging IVT (20% versus 7.7%, p = 0.01). Multivariable logistic and linear regression analysis confirmed the independent association of bridging IVT with sICH (aOR: 2.78, 95% CI: 1.02–7.56, p = 0.046), and edema volume (aOR: 8.70, 95% CI: 2.57–14.85, p = 0.006). Bridging IVT was associated with increased edema volume and risk for sICH as secondary injury volumes. The results of this study encourage direct EVT approaches, particularly in patients with higher likelihood of successful EVT.

Mechanical thrombectomy in stroke patients of working age: Real-world outcomes in Sweden

Introduction

Outcomes after mechanical thrombectomy (MT) in young stroke patients remain elusive due to small patient cohorts. We sought to determine outcomes after MT in stroke patients between ages 18 and 64 years and compare with outcomes in older patients in a large national stroke cohort.

Patients and methods

We used the Swedish National Stroke Registry and the Swedish National Endovascular Thrombectomy Registry to identify all patients treated with MT for anterior circulation occlusions. We examined outcome measures in terms of functional independence at 90 days (modified Rankin Scale score of 0–2), symptomatic intracerebral hemorrhage (sICH), and mortality at 90 days with multivariable logistic regression analysis.

Results

Of 2143 patients, 565 were between 18 and 64 years (26.4%) and 1179 (55.0%) were males. Analysis showed that patient aged 18–64 achieved higher rate of functional independence at 90 days (46.2% vs 28.4%, p < .001), had less often sICH (5.5% vs 6.8%, p = .008), and lower 90-day mortality rate (6.9% vs 17.7%, p < .001). Increasing age was associated with a lesser probability of functional independence at 90 days (adjusted odds ratio (aOR), 0.94; [95% confidence intervals (CIs) 0.93–0.95]), higher odds of mortality at 90 days (aOR, 1.05; [95% CIs 1.03–1.06]), and of sICH (aOR 1.03; [95% CIs 1.01–1.05]).

Conclusion

Patients aged 18–64 years demonstrated better outcome after thrombectomy regarding functional independence, sICH, and mortality at 90 days when compared to older ages.

Modeling ischemic stroke in a triculture neurovascular unit on-a-chip

BACKGROUND

In ischemic stroke, the function of the cerebral vasculature is impaired. This vascular structure is formed by the so-called neurovascular unit (NVU). A better understanding of the mechanisms involved in NVU dysfunction and recovery may lead to new insights for the development of highly sought therapeutic approaches. To date, there remains an unmet need for complex human in vitro models of the NVU to study ischemic events seen in the human brain.

METHODS

We here describe the development of a human NVU on-a-chip model using a platform that allows culture of 40 chips in parallel. The model comprises a perfused vessel of primary human brain endothelial cells in co-culture with induced pluripotent stem cell derived astrocytes and neurons. Ischemic stroke was mimicked using a threefold approach that combines chemical hypoxia, hypoglycemia, and halted perfusion.

RESULTS

Immunofluorescent staining confirmed expression of endothelial adherens and tight junction proteins, as well as astrocytic and neuronal markers. In addition, the model expresses relevant brain endothelial transporters and shows spontaneous neuronal firing. The NVU on-a-chip model demonstrates tight barrier function, evidenced by retention of small molecule sodium fluorescein in its lumen. Exposure to the toxic compound staurosporine disrupted the endothelial barrier, causing reduced transepithelial electrical resistance and increased permeability to sodium fluorescein. Under stroke mimicking conditions, brain endothelial cells showed strongly reduced barrier function (35-fold higher apparent permeability) and 7.3-fold decreased mitochondrial potential. Furthermore, levels of adenosine triphosphate were significantly reduced on both the blood- and the brain side of the model (4.8-fold and 11.7-fold reduction, respectively).

CONCLUSIONS

The NVU on-a-chip model presented here can be used for fundamental studies of NVU function in stroke and other neurological diseases and for investigation of potential restorative therapies to fight neurological disorders. Due to the platform's relatively high throughput and compatibility with automation, the model holds potential for drug compound screening.

Study Criteria Applied to Real Life-A Multicenter Analysis of Stroke Patients Undergoing Endovascular Treatment in Clinical Practice

Background

Randomized controlled clinical trials (RCT) have demonstrated the efficacy of endovascular treatment in anterior circulation large vessel occlusions. However, outcome of patients treated in daily practice differs from the results of the clinical trials. We hypothesize that this is attributable to the study criteria and that application of the criteria on patients undergoing endovascular therapy in daily routine would improve their outcome.

Methods and Results

Data from a multicenter prospective registry of GSR‐ET (German Stroke Registry – Endovascular Treatment) was used. Inclusion criteria and selectivity of SWIFT‐PRIME (Solitaire with the Intention for Thrombectomy as Primary Endovascular Treatment trial), MR CLEAN (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands trial), ESCAPE (Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion with Emphasis on Minimizing CT to Recanalization Times trial), DAWN (DWI or CTP Assessment with Clinical Mismatch in the Triage of Wake‐Up and Late Presenting Strokes Undergoing Neurointervention with Trevo trial) and DEFUSE‐3 (Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke trial) trials were analyzed. Baseline characteristics, procedural and outcome data of patients from GSR‐ET before and after selection were compared with the results of the RCTs. Furthermore, outcome of patients who underwent endovascular treatment despite not fulfilling the RCT criteria was analyzed. A total of 2611 patients were included (median age, 75 years; 49.6% women; median National Institute of Health Stroke Scale, 16). A minority of patients met all inclusion criteria, ranging from 3% (DEFUSE‐3 criteria) to 35% (MR CLEAN criteria). Of the patients fulfilling the MR CLEAN criteria, 41% of patients had a good clinical outcome, compared with 34% of patients that did not fulfill MR CLEAN criteria.

Conclusions

The RCTs represent a selected population with higher rates of good clinical outcome compared with daily practice. The good outcomes of RCTs can be reproduced in clinical routine in patients who fulfill the RCT inclusion criteria. Furthermore, patients who did not meet the criteria of the RCT still had substantial rates of good clinical outcome.

Evidence-Based Updates to Thrombectomy: Targets, New Techniques, and Devices

Endovascular thrombectomy (EVT) has been validated in several randomized controlled trials in recent years for its efficacy in the treatment of acute ischemic strokes (AIS) and is now the standard of care according to international guidelines. However, in about 20% of EVT procedures, recanalization is not achieved, and over 50% of patients who undergo EVT still do not have good functional outcome. In this article, we provide an extensive review of the latest evidence and developments in the field of EVT, with particular focus on the factors that improve patient outcomes. These factors include new and adjunctive techniques such as combination of direct aspiration and stent retriever, intra-arterial urokinase or 2b/3a inhibitors, rescue stenting, as well as novel devices including balloon guide catheters and the newer generations of aspiration catheters and stent retrievers. We also examined the latest notion of using first-pass effect (FPE) as the target to achieve during EVT, which has been associated with an improved functional outcome. While the field of EVT has been rapidly evolving, further research is required in specific AIS patient populations such as those with large ischemic core, late presentation beyond 24 h, posterior circulation strokes, and with distal medium vessel occlusion or tandem lesions to better assess its efficacy and safety.

Is Endovascular Therapy for Stroke Cost-Effective Globally? A Systematic Review of the Literature

OBJECTIVES

Cost-effectiveness of endovascular therapy (EVT) is a key consideration for broad use of this approach for emergent large vessel occlusion stroke. We evaluated the evidence on cost-effectiveness of EVT in comparison with best medical management from a global perspective.

MATERIALS AND METHODS

This systematic review of studies published between January 2010 and May 2020 evaluated the cost effectiveness of EVT for patients with large vessel occlusion acute ischemic stroke. The gain in quality adjusted life year (QALY) and incremental cost-effectiveness ratio (ICER), expressed as cost per QALY resulting from EVT, were recorded. The study setting (country, economic perspective), decision model, and data sources used in economic models of EVT cost-effectiveness were recorded.

RESULTS

Twenty-five original studies from 12 different countries were included in our review. Five of these studies were reported from a societal perspective; 18 were reported from a healthcare system perspective. Two studies used real-world data. The time horizon varied from 1 year to a lifetime; however, 18 studies reported a time horizon of >10 years. Twenty studies reported using outcome data from randomized, controlled clinical trials for their models. Nineteen studies reported using a Markov model. Incremental QALYs ranged from 0.09-3.5. All studies but 1 reported that EVT was cost-effective.

CONCLUSIONS

Evidence from different countries and economic perspectives suggests that EVT for stroke treatment is cost-effective. Most cost-effectiveness studies are based on outcome data from randomized clinical trials. However, there is a need to study the cost-effectiveness of EVT based solely on real-world outcome data.

[Remote proctoring in neuroradiological interventions]

Hintergrund

Endovaskuläre Verfahren haben einen festen Platz bei der Behandlung von Hirngefäßerkrankungen, z. B. die Thrombektomie beim Schlaganfall. Die ständige Weiterentwicklung der hierbei verwendeten Materialien (z. B. Katheter und Stents) fordert von den behandelnden Ärzten ein permanentes Lernen.

Fragestellung

Technische Hilfsmöglichkeiten zur Unterstützung bei neuen neuroendovaskulären Verfahren.

Material und Methode

Integration von Streamingtechnologien in das Ausbildungskonzept von Neuroradiologen.

Ergebnisse

Die Übertragung angiographischer Aufnahmen auf einen entfernten Computerarbeitsplatz in Echtzeit ist mittels spezifischer Streamingtechnologie ortsunabhängig möglich. Hierdurch kann ein neuroendovaskulärer Spezialist geographisch entfernte Interventionalisten bei der Durchführung eines Kathetereingriffes am Gehirn beraten, die Handhabung der verwendeten Materialien überblicken und bei Bedarf anleiten (Remote-Proctoring).

Schlussfolgerungen

Insbesondere bei Notfalleingriffen und während Reisebeschränkungen kann durch Zuschaltung eines weiteren neuroendovaskulären Spezialisten per Livestreaming die Patientensicherheit erhöht werden.

Impact of SMTP Targeting Plasminogen and Soluble Epoxide Hydrolase on Thrombolysis, Inflammation, and Ischemic Stroke

Stachybotrys microspora triprenyl phenol (SMTP) is a large family of small molecules derived from the fungus S. microspora. SMTP acts as a zymogen modulator (specifically, plasminogen modulator) that alters plasminogen conformation to enhance its binding to fibrin and subsequent fibrinolysis. Certain SMTP congeners exert anti-inflammatory effects by targeting soluble epoxide hydrolase. SMTP congeners with both plasminogen modulation activity and anti-inflammatory activity ameliorate various aspects of ischemic stroke in rodents and primates. A remarkable feature of SMTP efficacy is the suppression of hemorrhagic transformation, which is exacerbated by conventional thrombolytic treatments. No drug with such properties has been developed yet, and SMTP would be the first to promote thrombolysis but suppress disease-associated bleeding. On the basis of these findings, one SMTP congener is under clinical study and development. This review summarizes the discovery, mechanism of action, pharmacological activities, and development of SMTP.

Ischemic lesion water homeostasis after thrombectomy for large vessel occlusion stroke within the anterior circulation: The impact of age

The effect of age on lesion pathophysiology in the context of thrombectomy has been poorly investigated. We aimed to investigate the impact of age on ischemic lesion water homeostasis measured with net water uptake (NWU) within a multicenter cohort of patients receiving thrombectomy for anterior circulation large vessel occlusion (LVO) stroke. Lesion-NWU was quantified in multimodal CT on admission and 24 h for calculating Δ-NWU as their difference. The impact of age and procedural parameters on Δ-NWU was analyzed. Multivariable regression analysis was performed to identify significant predictors for Δ-NWU. Two hundred and four patients with anterior circulation stroke were included in the retrospective analysis. Comparison of younger and elderly patients showed no significant differences in NWU on admission but significantly higher Δ-NWU (p = 0.005) on follow-up CT in younger patients. In multivariable regression analysis, higher age was independently associated with lowered Δ-NWU (95% confidence interval: -0.59 to -0.16, p < 0.001). Although successful recanalization (TICI ≥ 2b) significantly reduced Δ-NWU progression by 6.4% (p < 0.001), younger age was still independently associated with higher Δ-NWU (p < 0.001). Younger age is significantly associated with increased brain edema formation after thrombectomy for LVO stroke. Younger patients might be particularly receptive targets for future adjuvant neuroprotective drugs that influence ischemic edema formation.

Predictors of outcome after mechanical thrombectomy for acute ischemic stroke in patients aged ≥90 years

BACKGROUND

Mechanical thrombectomy (MT) has established its role as a first-line treatment of acute ischemic stroke due to large vessel occlusions (LVO). However, patients older than 85 or even 80 years of age are commonly excluded from large randomized controlled stroke studies as this group was found to be associated with significantly poorer clinical outcome and increased mortality compared to younger patients. The aim of this study was to evaluate clinical and procedural factors associated with clinical outcome and mortality among nonagenarians with acute ischemic stroke treated with mechanical thrombectomy.

MATERIALS AND METHODS

This retrospective, single-center study was conducted on 38 patients with LVO treated with MT. Clinical features including baseline results, radiological imaging, procedural details and outcome results were documented and evaluated. Recanalization was assessed according to the TICI score. The clinical condition was evaluated on admission (NIHSS) and after 3 months (mRS).

RESULTS

The rate of successful recanalization (TICI ≥2b) was 84.2 % (32/38). Symptomatic intracranial hemorrhage (sICH) was observed in 3 (7.9 %) patients. After 90 days, the mortality rate was 47.4 %. Favorable clinical outcome (mRs 0-2) was regained in 28.9 % of the patients (11/38). Poor clinical outcome (mRs<2) was observed in 9 patients (23.7 %).

CONCLUSION

Very elderly patients with LVO should not be excluded from MT even if prognosis for good clinical outcome in this age group remains low and the procedure is more challenging. Long-term outcome is predicted by stroke severity (baseline NIHSS and occluded vessel) and hospital arrival time.

Role of B cells and the aging brain in stroke recovery and treatment

As mitigation of brain aging continues to be a key public health priority, a wholistic and comprehensive consideration of the aging body has identified immunosenescence as a potential contributor to age-related brain injury and disease. Importantly, the nervous and immune systems engage in bidirectional communication and can exert profound influence on each other. Emerging evidence supports numerous impacts of innate, inflammatory immune responses and adaptive T cell-mediated immunity in neurological function and diseased or injured brain states, such as stroke. Indeed, a growing body of evidence supports key impacts of brain-resident immune cell activation and peripheral immune infiltration in both the post-stroke acute injury phase and the long-term recovery period. As such, modulation of the immune system is an attractive strategy for novel therapeutic interventions for a devastating age-related brain injury for which there are few readily available neuroprotective treatments or neurorestorative approaches. However, the role of B cells in the context of brain function, and specifically in response to stroke, has not been thoroughly elucidated and remains controversial, leaving our understanding of neuroimmune interactions incomplete. Importantly, emerging evidence suggests that B cells are not pathogenic contributors to stroke injury, and in fact may facilitate functional recovery, supporting their potential value as novel therapeutic targets. By summarizing the current knowledge of the role of B cells in stroke pathology and recovery and interpreting their role in the context of their interactions with other immune cells as well as the immunosenescence cascades that alter their function in aged populations, this review supports an increased understanding of the complex interplay between the nervous and immune systems in the context of brain aging, injury, and disease.

Clinical relevance of asymptomatic intracerebral hemorrhage post thrombectomy depends on angiographic collateral score

Asymptomatic intracerebral hemorrhage (aICH) is a common phenomenon in patients with acute ischemic stroke (AIS) treated with endovascular thrombectomy (ET). However, the impact of aICH on the functional outcome remains widely unclear. In this study, we aimed at identifying predictors for aICH and analyzing its impact on functional outcome. Patients with AIS due to large artery occlusion in the anterior circulation treated with successful ET were enrolled in a tertiary stroke center. Patients with aICH or without intracerebral hemorrhage were included according to post-treatment CT performed within 72 h; 100 consecutive patients fulfilled the inclusion criteria and 30% classified with aICH. In logistic regression analysis, lower collateral score (OR 0.24; 95% CI 0.12-0.46, p < 0.0001) was significantly associated with aICH. Less patients with aICH achieved an independent outcome (mRS 0-2, 16.7% vs. 44.3%, p = 0.007). Poor outcome (mRS 4-6) was significantly higher in patients with aICH (41.4% vs. 70%, p = 0.021). Patients with aICH had a lower ratio of independent outcome (OR 0.23, 95% CI 0.05-0.1.05, p = 0.041) than without ICH. There were no differences concerning poor outcome (p = 0.5). Lower collateral status was a strong independent predictor for aICH. aICH after successful ET may decrease the likelihood of an independent functional outcome without influencing poor outcome.

Mechanical Thrombectomy in Acute Ischemic Stroke Using a Manually Expandable Stent Retriever (Tigertriever) : Preliminary Single Center Experience

OBJECTIVE

The aim of this study was to evaluate the safety and efficacy of a manually expandable stent retriever (Tigertriever, Rapid Medical, Yoqneam, Israel) in the treatment of acute ischemic stroke caused by intracranial large vessel occlusions (LVO).

METHODS

We performed a single center retrospective analysis of all patients treated by mechanical thrombectomy due to LVO using the Tigertriever. The angiographic and clinical success was evaluated by the modified thrombolysis in cerebral infarction score (mTICI) and the modified Rankin score (mRS).

RESULTS

A total of 68 acute intracranial arterial occlusions in 61 patients (42 female, median age 77 years, range 43-92 years) were treated by mechanical thrombectomy using the Tigertriever. The overall successful reperfusion rate (mTICI 2b-3) was 85.3% (58/68 occlusions) with a first pass effect (mTICI 3) of 23.5% (16/68 occlusions). In 57 of the 68 occlusions the Tigertriever was used on an intention to treat approach with a success rate of 86.0% and in the 11 remaining occlusions where the Tigertriever was used as a bail-out device the success rate was 81.9%. In seven patients a mild subarachnoid hemorrhage occurred (11.5%) and one symptomatic intracerebral hemorrhage was observed (1.6%). At discharge 39.3% of the patients (24/61) had a favorable outcome (mRS 0-2).

CONCLUSION

The Tigertriever offers a safe and effective treatment option in ischemic stroke due to LVOs with reperfusion rates and a safety profile similar to alternative devices. The Tigertriever is a promising bail-out tool in complex cases. Its role as a first line device has to be evaluated in further prospective studies.

Stroke patients treated by thrombectomy in real life differ from cohorts of the clinical trials: a prospective observational study

Background

Randomized controlled trials (RCTs) demonstrated efficacy and safety of endovascular treatment (ET) in anterior circulation large vessel occlusions (LVO). We aimed at investigating how stroke patients treated by thrombectomy in clinical practice and their outcome compare to cohorts and results of thrombectomy trials.

Methods

In a prospective study, we consecutively included stroke patients treated by thrombectomy (2015–2017). Baseline characteristics, procedural and outcome data were analyzed. Outcome was assessed by modified Rankin Scale (mRS) at 90 days. Ordinal regression analysis was performed to identify predictors of outcome.

Results

Thrombectomy was applied in 264 patients (median 75 years, 49.6% female). Median baseline National Institutes of Health Stroke Scale (NIHSS) was 16, 58.0% received concomitant intravenous thrombolysis, 62.1% were referred from external hospitals. Median Alberta Stroke Program Early CT Score (ASPECTS) was 7. Successful recanalization (modified Thrombolysis in Cerebral Infarction Score, mTICI 2b/3) was achieved in 72.0%. Symptomatic intracranial hemorrhage (sICH) occurred in 4.5%. Independent outcome (mRS 0–2) was achieved in 26.2%, poor outcome (mRS 5–6) in 49.2%. Only 33.5% met the stringent enrolment criteria of previous RCTs. Lower age, baseline NIHSS, pre-stroke mRS, higher ASPECTS, and successful recanalization were independent predictors of favourable outcome.

Conclusions

The majority of stroke patients treated by ET in clinical practice would not have qualified for randomization in prior RCTs. Outcome in real-life patient cohorts is worse than in the highly selected cohorts from randomized trials, while rates of successful recanalization, sICH and outcome predictors are the same. Our findings support ET in broader patient populations than in the RCTs and may improve treatment decision in individual stroke patients with LVO in clinical practice.

Endovascular Treatment of Very Elderly Patients Aged ≥90 With Acute Ischemic Stroke

Background

Patients aged ≥90 were excluded or under‐represented in past thrombectomy trials; thus, uncertainty remains whether treatment benefits can be expected regardless of age. This study investigates outcome and safety of thrombectomy in nonagenarians to improve decision making in a real‐world setting.

Methods and Results

All currently available data of patients aged ≥90 enrolled in the GSR‐ET (German Stroke Registry–Endovascular Treatment) were combined with a smaller cohort from 3 tertiary stroke centers. Baseline characteristics, procedural (Thrombolysis in Cerebral Infarction scale) and functional outcomes (modified Rankin Scale; mRS), as well as complications (symptomatic intracranial hemorrhage, serious adverse events; SAEs) were analyzed. Good functional outcome was defined as mRS ≤3 at 90‐days. 203 patients with anterior circulation stroke and prestroke mRS ≤3 were included. The rate of successful recanalization (Thrombolysis in Cerebral Infarction scale ≥2b) was 75.9% (154/203). Good functional outcome (mRS ≤3) was observed in 21.6% (41 of 193) at 90‐days. In‐hospital mortality was 27.1% (55 of 203) and increased significantly at 90 days to 48.9% (93 of 190; P<0.001). Symptomatic intracranial hemorrhage occurred in 3% (6 of 203) of patients. Logistic regression analysis identified Alberta Stroke Program Early CT Score (adjusted odds ratio, 1.93; 95% CI, 1.01–3.70; P=0.046) and initial National Institute of Health Stroke Scale (adjusted odds ratio, 0.85; 95% CI, 0.76–0.97; P=0.014) as independent predictors for good outcome. Patients with successful recanalization had a significant (P=0.001) shift of mRS distribution with higher rates of good functional outcomes (23.8% [34 of 143] versus 14.9% [7 of 47]) and lower mortality at 90‐days (46.8% [67 of 143] versus 55.3% [26 of 47]).

Conclusions

Despite high mortality and less frequent favorable outcome, our data suggest that thrombectomy is still effective and safe for nonagenarians. Decision making for thrombectomy in patients aged ≥90 should be based on a case‐by‐case basis with regard to initial National Institute of Health Stroke Scale and Alberta Stroke Program Early CT Score.

Emergency Conversion to General Anesthesia Is a Tolerable Risk in Patients Undergoing Mechanical Thrombectomy

BACKGROUND AND PURPOSE

Mechanical thrombectomy for acute ischemic stroke is performed with the patient under local anesthesia, conscious sedation, or general anesthesia. According to recent trials, up to 16% of patients require emergency conversion to general anesthesia during mechanical thrombectomy. This study investigated the procedural and clinical outcomes after emergency conversion in comparison with local anesthesia, conscious sedation, and general anesthesia.

MATERIALS AND METHODS

This retrospective study included 254 patients undergoing mechanical thrombectomy for acute large-vessel occlusion. The procedure was started with the patient either under local anesthesia, conscious sedation, or general anesthesia. Emergency conversion was defined as induction of general anesthesia during mechanical thrombectomy. The primary outcomes were successful reperfusion (TICI 2b/3) and functional independence (mRS at 90 days, ≤2).

RESULTS

Twenty-five patients (9.8%) required emergency conversion to general anesthesia. The time from admission to flow restoration was increased under general anesthesia (median, 137 minutes) and emergency conversion (median, 138 minutes) compared with local anesthesia (median 110 minutes). After adjustment for confounders, emergency conversion to general anesthesia and primary general anesthesia had comparable chances of successful reperfusion (OR = 1.28; 95% CI, 0.31-5.25). Patients with emergency conversion had a tendency toward higher chances of functional independence (OR = 4.48; 95% CI, 0.49-40.86) compared with primary general anesthesia, but not compared with local anesthesia (OR = 0.86; 95% CI, 0.14-5.11) and conscious sedation (OR = 1.07; 95% CI, 0.17-6.53).

CONCLUSIONS

Patients with emergency conversion did not have lower chances of successful reperfusion or functional independence compared those with primary general anesthesia, and time to flow restoration was also similar. We found no evidence supporting the primary induction of general anesthesia in patients at risk for emergency conversion.

Training and Supervision of Thrombectomy by Remote Live Streaming Support (RESS) : Randomized Comparison Using Simulated Stroke Interventions

PURPOSE

Stroke patients are excluded from expeditious thrombectomy in regions lacking neurointerventional specialists. An audiovisual online streaming system was tested, allowing a neurointerventional specialist located at a neurovascular center to supervise and instruct a thrombectomy performed at a distant hospital without being physically present (remote streaming support [RESS]).

METHODS

In total, 36 thrombectomy procedures were performed on a Mentice endovascular simulator by six radiologists not specialized in neurointerventions. Each radiologist was challenged with six different endovascular simulation scenarios under alternating conventional local support (specialist inside the room [LOS]) and RESS, which was performed using an advanced live streaming platform.

RESULTS

Both support modes led to a median of 2 attempts (interquartile range [IQR] 2.0-2.0 each) until successful recanalization. There was no statistically significant difference in time from first catheter insertion to recanalization between LOS (median 24.9 min, IQR 21.0-31.5 min) and RESS (23.9 min, IQR 21.7-28.7 min, p = 0.89). The percentage of thrombi covered by the stent-retriever and average speed when retrieving the stent-retriever (3.7 mm/s, IQR 3.25-5.35 mm/s vs. 3.6 mm/sec, IQR 2.5-4.7) were similar in both groups. Fluoroscopy time did not differ (19.0 min, IQR 16.9-23.5 min vs. 19.9 min, IQR 15.9-23.5 min) with a trend towards increased median amounts of contrast medium used under RESS (62.9 ml vs. 43.1 ml; p = 0.055).

CONCLUSION

This study confirmed the feasibility of RESS for thrombectomy procedures in a simulated environment. This serves as basis for future studies planned to analyze the effectiveness of RESS in a real-world environment and to test if it improves the learning curve of interventionalists with limited thrombectomy experience in remote areas.

S-Nitrosoglutathione Mimics the Beneficial Activity of Endothelial Nitric Oxide Synthase-Derived Nitric Oxide in a Mouse Model of Stroke

BACKGROUND

The nitric oxide (NO)-producing activity of endothelial nitric oxide synthase (eNOS) plays a significant role in maintaining endothelial function and protecting against the stroke injury. However, the activity of the eNOS enzyme and the metabolism of major NO metabolite S-nitrosoglutathione (GSNO) are dysregulated after stroke, causing endothelial dysfunction. We investigated whether an administration of exogenous of GSNO or enhancing the level of endogenous GSNO protects against neurovascular injury in wild-type (WT) and eNOS-null (endothelial dysfunction) mouse models of cerebral ischemia-reperfusion (IR).

METHODS

Transient cerebral ischemic injury was induced by middle cerebral artery occlusion (MCAO) for 60 minutes in male adult WT and eNOS null mice. GSNO (0.1 mg/kg body weight, intravenously) or N6022 (GSNO reductase inhibitor, 5.0 mg/kg body weight, intravenously) was administered 30 minutes before MCAO in preinjury and at the reperfusion in postinjury studies. Brain infarctions, edema, and neurobehavioral functions were evaluated at 24 hours after the reperfusion.

RESULTS

eNOS-null mice had a higher degree (P< .05) of injury than WT. Pre- or postinjury treatment with either GSNO or N6022 significantly reduced infarct volume, improved neurological and sensorimotor function in both WT and eNOS-null mice.

CONCLUSION

Reduced brain infarctions and edema, and improved neurobehavioral functions by pre- or postinjury GSNO treatment of eNOS knock out mice indicate that GSNO can attenuate IR injury, likely by mimicking the eNOS-derived NO-dependent anti-ischemic and anti-inflammatory functions. Neurovascular protection by GSNO/N6022 in both pre- and postischemic injury groups support GSNO as a promising drug candidate for the prevention and treatment of stroke injury.

Modeling the Optimal Transportation for Acute Stroke Treatment: The Impact of the Drip-and-Drive Paradigm

Background and Purpose- Health systems are faced with the challenge of ensuring fast access to appropriate therapy for patients with acute stroke. The paradigms primarily discussed are mothership and drip and ship. Less attention has been focused on the drip-and-drive (DD) paradigm. Our aim was to analyze whether and under what conditions DD would predict the greatest probability of good outcome for patients with suspected ischemic stroke in Northwestern Germany. Methods- Conditional probability models based on the decay curves for endovascular therapy and intravenous thrombolysis were created to determine the best transport paradigm, and results were displayed using map visualizations. Our study area consisted of the federal states of Lower Saxony, Hamburg, and Schleswig-Holstein in Northwestern Germany covering an area of 64 065 km² with a population of 12 703 561 in 2017 (198 persons per km²). In several scenarios, the catchment area, that is, the region that would result in the greatest probability of good outcomes, was calculated for each of the mothership, drip-and-ship, and the DD paradigms. Several different treatment time parameters were varied including onset-to-first-medical-response time, ambulance-on-scene time, door-to-needle time at primary stroke center, needle-to-door time, door-to-needle time at comprehensive stroke center, door-to-groin-puncture time, needle-to-interventionalist-leave time, and interventionalist-arrival-to-groin-puncture time. Results- The mothership paradigm had the largest catchment area; however, the DD catchment area was larger than the drip-and-ship catchment area so long as the needle-to-interventionalist-leave time and the interventionalist-arrival-to-groin-puncture time remain <40 minutes each. A slowed workflow in the DD paradigm resulted in a decrease of the DD catchment area to 1221 km² (2%). Conclusions- Our study suggests the largest catchment area for the mothership paradigm and a larger catchment area of DD paradigm compared with the drip-and-ship paradigm in Northwestern Germany in most scenarios. The existence of different paradigms allows the spread of capacities, shares the cost and hospital income, and gives primary stroke centers the possibility to provide endovascular therapy services 24/7.

Effect of intravenous alteplase on ischaemic lesion water homeostasis

BACKGROUND AND PURPOSE

Intravenous (IV) lysis with alteplase is known to increase biomarkers of blood-brain barrier breakdown and has therefore been associated with secondary injuries such as hemorrhagic transformation. The impact of alteplase on brain edema formation, however, has not been investigated yet. The purpose was to examine the effects of IV alteplase on ischaemic lesion water homeostasis differentiated from final tissue infarct in patients with and without successful endovascular therapy (sET).

METHODS

In all, 232 middle cerebral artery stroke patients were analyzed. 147 patients received IV alteplase, of whom 106 patients received subsequent sET. Out of 85 patients without IV alteplase, 50 received sET. Ischaemic brain edema was quantified at admission and follow-up computed tomography using quantitative lesion net water uptake (NWU) and its difference was calculated (ΔNWU). The relationship of alteplase on ΔNWU and edema-corrected final infarct volume was analyzed using univariate and multivariate linear regression models.

RESULTS

The mean ΔNWU was 11.8% (SD 7.9) in patients with alteplase and 11.5% (SD 8.3) in patients without alteplase (P = 0.8). Alteplase was not associated with lowered ΔNWU whilst being associated with reduced edema-corrected tissue infarct volume [-27.4 ml, 95% confidence interval (CI) -49.4 to -5.4 ml; P = 0.02], adjusted for the Alberta Stroke Program Early Computed Tomography Score and recanalization status. In patients with sET, ΔNWU was 10.5% (95% CI 6.3%-10.5%) for patients with IV alteplase and 8.4% (95% CI 9.1%-12.0%) for patients without IV alteplase.

CONCLUSION

The application of IV alteplase did not significantly alter ischaemic lesion water homeostasis but was associated with reduced edema-corrected tissue infarct volume, which might be directly linked to improved functional outcome.

Functional Outcome Following Stroke Thrombectomy in Clinical Practice

Background and Purpose—

Endovascular treatment for large vessel occlusion in ischemic stroke has proven to be effective in large clinical trials. We aimed to provide real-world estimates of endovascular treatment reperfusion rates and functional outcome on a countrywide scale.

Methods—

Two thousand seven hundred ninety-four patients with large vessel occlusion were included into an investigator-initiated, industry-independent, prospective registry in 25 sites in Germany between June 2015 and April 2018. The primary outcome was the score on the modified Rankin Scale ranging from zero (no symptoms) to 6 (death) at 3 months. Secondary analyses included the prediction of a good outcome (modified Rankin Scale, 0–2). Dichotomized analyses of predictors were performed using logistic regression adjusted for potential confounders.

Results—

Median age was 75 years (interquartile range, 64–82); median National Institutes of Health Stroke Scale score was 15 (interquartile range, 10–19). Vessel occlusion was in the anterior circulation in 2265 patients (88%) and in the posterior circulation in 303 patients (12%). Intravenous alteplase before endovascular treatment was given in 1457 patients (56%). Successful reperfusion was achieved in 2143 subjects (83%). At 3 months, 854 patients (37%) showed a good outcome; mortality was 29%. There was no difference between anterior and posterior circulation occlusions ( P =0.27). Significant predictors for a good outcome were younger age (odds ratio [OR], 1.06; 95% CI, 1.05–1.07), no interhospital transfer (OR, 1.39; 95% CI, 1.03–1.88), lower stroke severity (OR, 1.10; 95% CI, 1.08–1.13), smaller infarct size (OR, 1.26; 95% CI, 1.15–1.39), alteplase use (OR, 1.49; 95% CI, 1.08–2.06), and reperfusion success (OR, 1.69; 95% CI, 1.45–1.96).

Conclusions—

High rates of favorable outcome can be achieved on a countrywide scale by endovascular treatment. Mortality appears to be greater in the daily routine than otherwise reported by authors of large randomized trials. There were no outcome differences between the anterior and posterior circulation.

Clinical Trial Registration—

URL: https://www.clinicaltrials.gov . Unique identifier: NCT03356392.

Mechanical thrombectomy in nonagenarians with acute ischemic stroke

Background

Mechanical thrombectomy (MT) is a safe and effective therapy for ischemic stroke. Nevertheless, very elderly patients aged ≥90 years were either excluded or under-represented in previous trials. It remains uncertain whether MT is warranted for this population or whether there should be an upper age limit.

Methods

We retrospectively reviewed 79 patients with stroke aged ≥90 years from three neurointerventional centers who underwent MT between 2013 and 2017. Good functional outcome was defined as modified Rankin scale (mRS) ≤2 and assessed at 90-day follow-up. Successful recanalization was graded by Thrombolysis in Cerebral Infarction Scale (TICI) ≥2 b. Feasibility and safety assessments included unsuccessful recanalization attempts (TICI 0), time from groin puncture to recanalization, symptomatic intracranial hemorrhage (sICH), mortality, and intervention-related serious adverse events.

Results

Only occlusions within the anterior circulation were included. Median time from groin puncture to recanalization was 39 min (IQR 25–57 min). The rate of successful recanalization (TICI ≥2 b) was 69.6% (55/79). Good functional outcome (mRS ≤2) at 90 days was observed in 16% (12/75) of patients. In-hospital mortality was 29.1% (23/79) and increased significantly at 90 days (46.7%, 35/75; p<0.001). sICH occurred in 5.1% (4/79) of patients. No independent predictor for good functional outcome (mRS ≤2) at 90 days was identified through logistic regression analysis.

Conclusion

MT in nonagenarians leads to high mortality rates and less frequently good functional outcome compared with younger patient cohorts in previous large randomized trials. However, MT appears to be safe and beneficial for a certain number of very elderly patients and therefore should generally not be withheld from nonagenarians.