Validation of the extended thrombolysis in cerebral infarction score in a real world cohort

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.

Assessment of automated TICI scoring during endovascular treatment in patients with an ischemic stroke

BACKGROUND

The extended Thrombolysis in Cerebral Infarction (eTICI) score is used in digital subtraction angiography (DSA) to quantify reperfusion grade in patients with an ischemic stroke who undergo endovascular thrombectomy (EVT). A previously developed automatic TICI score (autoTICI), which quantifies the ratio of reperfused pixels after EVT, demonstrates good correlation with eTICI.

OBJECTIVE

To evaluate the autoTICI model in a large multicenter registry of patients with an ischemic stroke, investigate the association with visual eTICI, and compare prediction of functional outcome between autoTICI and eTICI.

METHODS

Patients in the MR CLEAN Registry with an internal carotid artery, M1, and M2 occlusion were selected if both anteroposterior and lateral views were present in pre- and post-EVT DSA scans. The autoTICI score was compared with eTICI in predicting favorable functional outcome (modified Rankin Scale score 0-2), using area under the receiver operating characteristics curve (AUC) with a multivariable logistic regression model including known prognostic characteristics.

RESULTS

In total 421 of 3637 patients were included. AutoTICI was significantly associated with eTICI non-linearly (below 70% cOR=2.3 (95% CI 2.1 to 2.5), above 70% cOR=1.6 (95% CI 1.6 to 1.7) per 10% increment). The AUC of the model predicting favorable functional outcome was similar for autoTICI and eTICI (0.86, 95% CI 0.82 to 0.92 vs 0.86, 95% CI 0.83 to 0.90, P=0.73) and was higher than for a model with prognostic patient characteristics alone (0.86 vs 0.84, P=0.01).

CONCLUSION

Automatic quantitative assessment of reperfusion after EVT is associated with eTICI, and prediction of functional outcome is similar to that with visual eTICI. Therefore, autoTICI could be used as an alternative or additional review for visual reperfusion assessment to facilitate reproducible and uniform reporting.

Treatment of Acute Ischemic Stroke: The Last 30 Years of Trials and Tribulations

The landscape of acute ischemic stroke management has undergone a substantial transformation over the past 3 decades, mirroring our enhanced comprehension of the pathology and progress in diagnostic techniques, therapeutic interventions, and preventive measures. The 1990s marked a pivotal moment in stroke care with the integration of intravenous thrombolytics. However, the most significant paradigm shift in recent years has undoubtedly been the advent of endovascular thrombectomy. This article endeavors to deliver an exhaustive analysis of this revolutionary progression.

Effect of anesthetic strategies on distal stroke thrombectomy in the anterior and posterior cerebral artery

BACKGROUND

Numerous questions regarding procedural details of distal stroke thrombectomy remain unanswered. This study assesses the effect of anesthetic strategies on procedural, clinical and safety outcomes following thrombectomy for distal medium vessel occlusions (DMVOs).

METHODS

Patients with isolated DMVO stroke from the TOPMOST registry were analyzed with regard to anesthetic strategies (ie, conscious sedation (CS), local (LA) or general anesthesia (GA)). Occlusions were in the P2/P3 or A2-A4 segments of the posterior and anterior cerebral arteries (PCA and ACA), respectively. The primary endpoint was the rate of complete reperfusion (modified Thrombolysis in Cerebral Infarction score 3) and the secondary endpoint was the rate of modified Rankin Scale score 0-1. Safety endpoints were the occurrence of symptomatic intracranial hemorrhage and mortality.

RESULTS

Overall, 233 patients were included. The median age was 75 years (range 64-82), 50.6% (n=118) were female, and the baseline National Institutes of Health Stroke Scale score was 8 (IQR 4-12). DMVOs were in the PCA in 59.7% (n=139) and in the ACA in 40.3% (n=94). Thrombectomy was performed under LA±CS (51.1%, n=119) and GA (48.9%, n=114). Complete reperfusion was reached in 73.9% (n=88) and 71.9% (n=82) in the LA±CS and GA groups, respectively (P=0.729). In subgroup analysis, thrombectomy for ACA DMVO favored GA over LA±CS (aOR 3.07, 95% CI 1.24 to 7.57, P=0.015). Rates of secondary and safety outcomes were similar in the LA±CS and GA groups.

CONCLUSION

LA±CS compared with GA resulted in similar reperfusion rates after thrombectomy for DMVO stroke of the ACA and PCA. GA may facilitate achieving complete reperfusion in DMVO stroke of the ACA. Safety and functional long-term outcomes were comparable in both groups.

Collateral Status Modification of the Association Between Blood Pressure Variation Within 72 Hours After Endovascular Treatment and Clinical Outcome in Acute Ischemic Stroke: A Retrospective Cohort Study

Background

Blood pressure variation and collateral status have been reported to be associated with clinical outcome in patients with acute ischemic stroke who received endovascular treatment; however, the relationship between blood pressure variation within 72 hours after EVT and clinical outcome in different collateral status remains unclear.

Methods

Acute ischemic stroke patients due to large vessel occlusion with EVT were retrospectively enrolled. We classified participants into poor collateral (ASITN/SIR grade <2) and good collateral subgroups (ASITN/SIR grade ≥2). The primary outcome was unfavorable neurological outcome defined as a 3-month modified Rankin Scale (mRS) score ≥2. The interactive effect was tested to determine the influence of collateral status on the association between BP variation and clinical outcome.

Results

A total of 545 patients were included. The poor collateral subgroup was detected in 198 patients with an average age of 70.2 years. The association between BP variation and primary outcome did not differ under different collateral status (P for interaction >0.05). However, the association between the mean and coefficient of variation (CV) values of DBP and 3-month mortality was significantly discrepant under different collateral status (P for interaction <0.05). In the good collateral subgroup, higher mean DBP was associated with a lower risk of 3-month mortality (OR 0.95, 95% CI 0.91-1, P = 0.033) compared with the poor subgroup (OR 1.04, 95% CI 0.97-1.1, P = 0.286). In addition, a higher CV of DBP was associated with a higher risk of 3-month mortality (OR 1.24, 95% CI 1.13-1.36, P < 0.01) compared with poor status (OR 1.08, 95% CI 0.94-1.23, P=0.275).

Conclusion

For patients who received EVT with good collateral status, increased CV of DBP was significantly associated with higher 3-month mortality, while higher mean DBP within 72 h after EVT was associated with a decrease in 3-month mortality.

The effect of butylphthalide on improving the neurological function of patients with acute anterior circulation cerebral infarction after mechanical thrombectomy

Butylphthalide can improve blood circulation in patients with acute cerebral infarction. Complement 3a receptor 1 (C3aR1) is involved in the regulation of innate immune response and pathogen monitoring, which is closely related to the pathophysiological processes of breast cancer, neurogenesis and lipid catabolism. Our study explored the therapeutic effect of butylphthalide on improving the neurological function of patients with acute anterior circulation cerebral infarction after mechanical thrombectomy, and evaluated the correlation between serum C3aR1 and butylphthalide on improving the neurological function after mechanical thrombectomy. 288 patients with acute anterior circulation cerebral infarction who were admitted to our hospital from January 2019 to November 2022 and were treated with mechanical thrombectomy for the first time were included in this retrospective study and divided into the butylphthalide group and control group that they received treatment methods. The National Institutes of Health Stroke Scale (NIHSS) scale was used to evaluate the patient neurological function treatment efficacy, and the modified Rankin Scale (mRS) scale was used to measure the patient neurological function status 3 months after surgery. Enzyme-linked immunosorbent assay method was used to determine the content of C3aR1 in serum. Two weeks after thrombus removal, the NIHSS efficacy of the butylphthalide group and the control group were 94.44% and 72.22%, respectively. The butylphthalide group was significantly higher than the control group (P < .001). Three months after the operation, the mRS score of the butylphthalide group was significantly lower than that of the control group (P = .001), and the excellent and good rate was significantly higher than that of the control group (P < .001). The serum C3aR1 level of the butylphthalide group was significantly lower than that of the control group 2 weeks after operation and 3 months after operation (P < .001). The serum C3aR1 was positively correlated with the efficacy of NIHSS (R = 0.815, P = .004), which was positively correlated with mRS score (R = 0.774, P = .007). Butylphthalide can improve the therapeutic effect of neurological function in patients with acute anterior circulation cerebral infarction after mechanical thrombus removal. The patient serum C3aR1 is related to the patient neurotherapy efficacy and neurological function status, and its level can reflect the patient neurological function recovery to a certain extent.

Successful reperfusion in relation to the number of passes: comparing outcomes of first pass expanded Treatment In Cerebral Ischemia (eTICI) 2B with multiple-pass eTICI 3

BACKGROUND

Higher expanded Treatment In Cerebral Ischemia (eTICI) reperfusion scores after endovascular treatment (EVT) are associated with better outcomes. However, the influence of the number of passes on this association is unclear. We aimed to compare outcomes of single-pass good reperfusion (eTICI 2B) with multiple-pass excellent/complete reperfusion (eTICI 2C/3) in daily clinical practice.

METHODS

We compared outcomes of patients in the MR CLEAN Registry with good reperfusion (eTICI 2B) in a single pass to those with excellent/complete reperfusion (eTICI 2C/3) in multiple passes. Regression models were used to investigate the association of single-pass eTICI 2B versus multiple-pass eTICI 2C/3 reperfusion with 90-day functional outcome (modified Rankin Scale (mRS)), functional independence (mRS 0-2), per-procedural complications and safety outcomes.

RESULTS

We included 699 patients: 178 patients with single-pass eTICI 2B, and 242 and 279 patients with eTICI 2C/3 after 2 and ≥3 passes, respectively. Patients with eTICI 2C/3 after 2 or ≥3 passes did not achieve significantly better functional outcomes compared with patients with single-pass eTICI 2B (adjusted common OR (acOR) 1.06, 95% CI 0.75 to 1.50 and acOR 0.88, 95% CI 0.74 to 1.05 for 90-day mRS, and adjusted OR (aOR) 1.24, 95% CI 0.78 to 1.97 and aOR 0.79, 95% CI 0.52 to 1.22 for functional independence).

CONCLUSIONS

Our results did not show better outcomes for patients who achieved eTICI 2C/3 in multiple, that is, two or more, passes when compared with patients with single-pass eTICI 2B. However, this concerns observational data. Further research is necessary to investigate the per-pass effect in relation to reperfusion and functional outcome.

An Optimal Animal Model of Ischemic Stroke Established by Digital Subtraction Angiography-Guided Autologous Thrombi in Cynomolgus Monkeys

Objective

Ischemic stroke seriously threatens human health, characterized by the high rates of incidence, disability, and death. Developing a reliable animal model that mimics most of the features of stroke is critical for pathological studies and clinical research. In this study, we aimed to establish and examine a model of middle cerebral artery occlusion (MCAO) guided by digital subtraction angiography (DSA) in cynomolgus monkeys.

Materials and Methods

In this study, 15 adult male cynomolgus monkeys were enrolled. Under the guidance of DSA, a MCAO model was established by injecting an autologous venous clot into the middle cerebral artery (MCA) via femoral artery catheter. Thrombolytic therapy with alteplase (rt-PA) was given to eight of these monkeys at 3 h after the occlusion. Blood test and imaging examination, such as computed tomography angiography (CTA), CT perfusion (CTP), brain magnetic resonance imaging (MRI), and brain magnetic resonance angiography (MRA), were performed after the operation to identify the post-infarction changes. The behavioral performance of cynomolgus monkeys was continuously observed for 7 days after operation. The animals were eunthanized on the 8th day after operation, and then the brain tissues of monkeys were taken for triphenyltetrazolium chloride (TTC) staining.

Results

Among the 15 cynomolgus monkeys, 12 of them were successfully modeled, as confirmed by the imaging findings and staining assessment. One monkey died of brain hernia resulted from intracranial hemorrhage confirmed by necropsy. DSA, CTA, and MRA indicated the presence of an arterial occlusion. CTP and MRI showed acute focal cerebral ischemia. TTC staining revealed infarct lesions formed in the brain tissues.

Conclusion

Our study may provide an optimal non-human primate model for an in-depth study of the pathogenesis and treatment of focal cerebral ischemia.

Aspiration Versus Stent Retriever Thrombectomy for Distal, Medium Vessel Occlusion Stroke in the Posterior Circulation: A Subanalysis of the TOPMOST Study

BACKGROUND

The optimal endovascular strategy for reperfusing distal medium-vessel occlusions (DMVO) remains unknown. This study evaluates angiographic and clinical outcomes of thrombectomy strategies in DMVO stroke of the posterior circulation.

METHODS

TOPMOST (Treatment for Primary Medium Vessel Occlusion Stroke) is an international, retrospective, multicenter, observational registry of patients treated for DMVO between January 2014 and June 2020. This study analyzed endovascularly treated isolated primary DMVO of the posterior cerebral artery in the P2 and P3 segment. Technical feasibility was evaluated with the first-pass effect defined as a modified Thrombolysis in Cerebral Infarction Scale score of 3. Rates of early neurological improvement and functional modified Rankin Scale scores at 90 days were compared. Safety was assessed by the occurrence of symptomatic intracranial hemorrhage and intervention-related serious adverse events.

RESULTS

A total of 141 patients met the inclusion criteria and were treated endovascularly for primary isolated DMVO in the P2 (84.4%, 119) or P3 segment (15.6%, 22) of the posterior cerebral artery. The median age was 75 (IQR, 62-81), and 45.4% (64) were female. The initial reperfusion strategy was aspiration only in 29% (41) and stent retriever in 71% (100), both achieving similar first-pass effect rates of 53.7% (22) and 44% (44; P=0.297), respectively. There were no significant differences in early neurological improvement (aspiration: 64.7% versus stent retriever: 52.2%; P=0.933) and modified Rankin Scale rates (modified Rankin Scale score 0-1, aspiration: 60.5% versus stent retriever 68.6%; P=0.4). In multivariable logistic regression analysis, the time from groin puncture to recanalization was associated with the first-pass effect (adjusted odds ratio, 0.97 [95% CI, 0.95-0.99]; P<0.001) that in turn was associated with early neurological improvement (aOR, 3.27 [95% CI, 1.16-9.21]; P<0.025). Symptomatic intracranial hemorrhage occurred in 2.8% (4) of all cases.

CONCLUSIONS

Both first-pass aspiration and stent retriever thrombectomy for primary isolated posterior circulation DMVO seem to be safe and technically feasible leading to similar favorable rates of angiographic and clinical outcome.

Is a picture-perfect thrombectomy necessary in acute ischemic stroke?

BACKGROUND

The benefit of complete reperfusion (modified Thrombolysis in Cerebral Infarction (mTICI) 3) over near-complete reperfusion (≥90%, mTICI 2c) remains unclear. The goal of this study is to compare clinical outcomes between mechanical thrombectomy (MT)-treated stroke patients with mTICI 2c versus 3.

METHODS

This is a retrospective study from the Stroke Thrombectomy and Aneurysm Registry (STAR) comprising 33 centers. Adults with anterior circulation arterial vessel occlusion who underwent MT yielding mTICI 2c or mTICI 3 reperfusion were included. Patients were categorized based on reperfusion grade achieved. Primary outcome was modified Rankin Scale (mRS) 0-2 at 90 days. Secondary outcomes were mRS scores at discharge and 90 days, National Institutes of Health Stroke Scale score at discharge, procedure-related complications, and symptomatic intracerebral hemorrhage.

RESULTS

The unmatched mTICI 2c and mTICI 3 cohorts comprised 519 and 1923 patients, respectively. There was no difference in primary (42.4% vs 45.1%; p=0.264) or secondary outcomes between the unmatched cohorts. Reperfusion status (mTICI 2c vs 3) was also not predictive of the primary outcome in non-imputed and imputed multivariable models. The matched cohorts each comprised 191 patients. Primary (39.8% vs 47.6%; p=0.122) and secondary outcomes were also similar between the matched cohorts, except the 90-day mRS which was lower in the matched mTICI 3 cohort (p=0.049). There were increased odds of the primary outcome with mTICI 3 in patients with baseline mRS ≥2 (36% vs 7.7%; p=0.011; pinteraction=0.014) and a history of stroke (42.3% vs 15.4%; p=0.027; pinteraction=0.041).

CONCLUSIONS

Complete and near-complete reperfusion after MT appear to confer comparable outcomes in patients with acute stroke.

Heterogeneity of the Relative Benefits of TICI 2c/3 over TICI 2b50/2b67 : Are there Patients who are less Likely to Benefit?

PURPOSE

Incomplete reperfusion after mechanical thrombectomy (MT) is associated with a poor outcome. Rescue therapy would potentially benefit some patients with an expanded treatment in cerebral ischemia score (eTICI) 2b50/2b67 reperfusion but also harbors increased risks. The relative benefits of eTICI 2c/3 over eTICI 2b50/67 in clinically important subpopulations were analyzed.

METHODS

Retrospective analysis of our institutional database for all patients with occlusion of the intracranial internal carotid artery (ICA) or the M1/M2 segment undergoing MT and final reperfusion of ≥eTICI 2b50 (903 patients). The heterogeneity in subgroups of different time metrics, age, National Institutes of Health Stroke Scale (NIHSS), number of retrieval attempts, Alberta Stroke Programme Early CT Score (ASPECTS) and site of occlusion using interaction terms (p_i) was analyzed.

RESULTS

The presence of eTICI 2c/3 was associated with better outcomes in most subgroups. Time metrics showed no interaction of eTICI 2c/3 over eTICI 2b50/2b67 and clinical outcomes (onset to reperfusion p_i = 0.77, puncture to reperfusion p_i = 0.65, onset to puncture p_i = 0.63). An eTICI 2c/3 had less consistent association with mRS ≤2 in older patients (>82 years, p_i = 0.038) and patients with either lower NIHSS (≤9) or very high NIHSS (>19, p_i = 0.01). Regarding occlusion sites, the beneficial effect of eTICI 2c/3 was absent for occlusions in the M2 segments (aOR 0.73, 95% confidence interval [CI] 0.33-1.59, p_i = 0.018).

CONCLUSION

Beneficial effect of eTICI 2c/3 over eTICI 2b50/2b67 only decreased in older patients, M2-occlusions and patients with either low or very high NIHSS. Improving eTICI 2b50/2b67 to eTICI 2c/3 in those subgroups may be more often futile.

Embotrap Extraction & Clot Evaluation & Lesion Evaluation for NeuroThrombectomy (EXCELLENT) Registry design and methods

Background

Relationships between occlusive clot histopathology, baseline characteristics, imaging findings, revascularization rates, and clinical outcomes of stroke patients with large vessel occlusion (LVO) are not well understood. This study will assess the real-world experience on the efficacy and safety of using the EmboTrap device as the first approach in LVO patients and explore the associations between clot histological characteristics, imaging and clinical findings, revascularization rates, and clinical outcomes.

Methods

Prospective, global, multicenter, single-arm, imaging core laboratory, and clot analysis central laboratory observational registry. Adult patients (>18 years) with LVO, treated with EmboTrap as the first attempted device, will be eligible for study participation.

Results

Up to 1000 subjects at 50 international sites may be enrolled. Occlusive clots will be collected from at least 500 subjects. Independent central and imaging core laboratories will perform clot analysis and image adjudication. Statistical analysis will assess the association between imaging and clinical findings, clot characteristics, subject comorbidities, revascularization, and clinical outcomes. Study endpoints are functional independence (modified Rankin Scale score ≤2 at 90 days), expanded Thrombolysis In Cerebral Infarction (eTICI) score ≥2b50 rate, first-pass effect, number of passes, embolization into new territory, symptomatic intracranial hemorrhage, and 90-day mortality.

Conclusions

The EXCELLENT registry will provide reproducible effectiveness and safety data of EmboTrap for its use for mechanical thrombectomy. Additionally, the study will characterize the blood clots retrieved during mechanical thrombectomy with respect to their composition and histopathological analysis and potential correlations with clinical and imaging findings.

Trial registration number

NCT03685578.

Interobserver Agreement in Scoring Angiographic Results of Basilar Artery Occlusion Stroke Therapy

BACKGROUND AND PURPOSE

The modified TICI Infarction grading system is a metric currently used to evaluate angiographic results of thrombectomy for large-vessel occlusion in ischemic stroke. Originally designed for evaluating MCA territories, it is currently used for other vessel occlusions, including the posterior circulation. We postulate that the modified TICI use for the posterior circulation is not accurate due to the different vascular territories supplied by vertebrobasilar vasculature, making grading more complex.

MATERIALS AND METHODS

We collected angiographic results from 30 patients who presented with acute posterior circulation occlusions between 2015 and 2018 and underwent thrombectomy in our institution. Eight observers were asked to evaluate the TICI scores before and after thrombectomy. The multirater statistics were computed using Fleiss κ analysis. Further data were collected regarding the potential brain territories at risk and the existence of atherosclerotic disease in the basilar artery.

RESULTS

The overall agreement κ reached 0.277 (SD, 0.013), which suggests a "fair" agreement among the raters. On average, 45% of observers achieved a high accuracy in predicting brain areas at risk of ischemia. As for the existence of basilar atherosclerotic disease, a high agreement (defined as at least 5 of 6 observers) was seen in 20 of the 30 patients.

CONCLUSIONS

Despite TICI being ubiquitous in stroke diagnostics, the high variability of posterior circulation TICI scores calls into question its use in these strokes. Other methods should be developed to assess recanalization in the posterior circulation.

Modelling the impact of clot fragmentation on the microcirculation after thrombectomy

Many ischaemic stroke patients who have a mechanical removal of their clot (thrombectomy) do not get reperfusion of tissue despite the thrombus being removed. One hypothesis for this 'no-reperfusion' phenomenon is micro-emboli fragmenting off the large clot during thrombectomy and occluding smaller blood vessels downstream of the clot location. This is impossible to observe in-vivo and so we here develop an in-silico model based on in-vitro experiments to model the effect of micro-emboli on brain tissue. Through in-vitro experiments we obtain, under a variety of clot consistencies and thrombectomy techniques, micro-emboli distributions post-thrombectomy. Blood flow through the microcirculation is modelled for statistically accurate voxels of brain microvasculature including penetrating arterioles and capillary beds. A novel micro-emboli algorithm, informed by the experimental data, is used to simulate the impact of micro-emboli successively entering the penetrating arterioles and the capillary bed. Scaled-up blood flow parameters-permeability and coupling coefficients-are calculated under various conditions. We find that capillary beds are more susceptible to occlusions than the penetrating arterioles with a 4x greater drop in permeability per volume of vessel occluded. Individual microvascular geometries determine robustness to micro-emboli. Hard clot fragmentation leads to larger micro-emboli and larger drops in blood flow for a given number of micro-emboli. Thrombectomy technique has a large impact on clot fragmentation and hence occlusions in the microvasculature. As such, in-silico modelling of mechanical thrombectomy predicts that clot specific factors, interventional technique, and microvascular geometry strongly influence reperfusion of the brain. Micro-emboli are likely contributory to the phenomenon of no-reperfusion following successful removal of a major clot.

Evolution of Stroke Thrombectomy Techniques to Optimize First-Pass Complete Reperfusion

Since 2015, endovascular therapy (EVT) has become the standard of care for acute ischemic stroke (AIS) due to large vessel occlusion. It is a safe and highly effective treatment, and its number needed to treat of 2.6 is one of the highest throughout medicine. The ultimate goal when performing EVT is to maximize chances of good outcome through achievement of fast first-pass complete reperfusion, as incomplete and delayed reperfusion increases complication rates and negatively affects outcome. Since EVT has been established as standard of care, new devices have been developed and treatment techniques have been refined. This review provides a brief overview about the rationale for and history of EVT, followed by a detailed step-by-step description of how to perform EVT using the BADDASS (BAlloon guide with large bore Distal access catheter with Dual Aspiration with Stent-retriever as Standard approach), a combined technique, which is in our opinion the safest and most effective way to achieve fast first-pass complete reperfusion. We also discuss treatment strategies for patients with simultaneous high-grade carotid stenosis/pseudoocclusion/occlusion and gaining carotid access in challenging arch anatomy, as these are commonly encountered situations in AIS, and conclude with an outlook on new technologies and future directions of EVT.

Effect of Balloon Guide Catheter Utilization on the Incidence of Sub-angiographic Peripheral Emboli on High-Resolution DWI After Thrombectomy: A Prospective Observational Study

Background: Thrombus fragmentation causing distal emboli is a feared complication during mechanical thrombectomy (MT). We aimed to investigate the impact of procedural parameters and thrombus properties on the incidence of peripheral emboli after MT for large vessel occlusions (LVO).

Methods: We performed a prospective analysis of patients with LVO stroke successfully treated with MT, defined as a score of 2b, 2c, or 3 on the thrombolysis in cerebral infarction (TICI) scale. A follow-up MRI including high-resolution diffusion-weighted imaging (DWI) was performed within 24 h following MT. The primary endpoint was the number and volume of peripheral emboli, classified as punctuate DWI lesions distant to the diffusion-restricted core lesion. Further analysis included the influence of baseline characteristics, procedural and outcome parameters, and thrombus properties on peripheral emboli.

Results: Thirty-seven patients with successful MT met the inclusion criteria. Use of a balloon guide catheter (BGC) and TICI were the only independent predictors for a reduced number of peripheral emboli. The use of a BGC led to a significant reduction in the number and volume of peripheral emboli, with a median number/volume of peripheral emboli of 4.5/287 μl (IQR 1.25–8.25/76–569 μl) vs. 12/938 μl (IQR 4–19/242–1,836 μl). In cases where BGC was not employed, the number of peripheral emboli increased with decreasing TICI scores.

Conclusions: BGC-aided MT reduces the number of peripheral emboli in successful but incomplete reperfusion (TICI 2b and 2c). The effectiveness of this strategy therefore goes above and beyond that which can be demonstrated by the TICI score alone.

Optimizing Stroke Care for Patients with Large Vessel Occlusions: Current State of the Art and Future Directions

Acute ischemic stroke (AIS) is a severely disabling disease. Endovascular therapy is a powerful and highly effective treatment option for these patients and has recently become standard of care. The benefits of endovascular treatment (EVT) are tremendous both from a patient and from an economic perspective, since it dramatically improves individual patient outcomes while reducing long-term healthcare costs at the same time. The effect of EVT is highly time-dependent. Thus, the overarching goal in AIS is to quickly transport and diagnose the patient to minimize treatment delays. In this review, we provide an overview about the current state of stroke care, propose a fast and simplified imaging protocol and management approach for AIS patients. We also highlight the challenges we are currently facing in endovascular stroke treatment and suggest possible solutions to overcome these.

Sub-angiographic peripheral emboli in high resolution DWI after endovascular recanalization

Background and aim

To analyze the incidence of peripheral emboli after successful mechanical thrombectomy (MT) of intracranial large vessel occlusions (LVO).

Methods

We performed a prospective analysis of patients with intracranial LVO who underwent successful MT and received a 1.5 T MRI including diffusion-weighted imaging (DWI) in standard- and high-resolution as well as susceptibility-weighted imaging (SWI) on the day following the intervention. Reperfusion grade was assessed on post-thrombectomy digital subtraction angiography (DSA) using the expanded thrombolysis in cerebral infarction (eTICI) scale. Punctuate DWI lesions distal to the DWI core lesion were classified as peripheral emboli. DWI lesions outside the primary affected vascular territory were classified as emboli into new territories. Additionally, SWI and post-thrombectomy DSA were analyzed and correlated to findings on DWI.

Results

Twenty-eight patients undergoing successful MT met the inclusion criteria. In 26/28 patients (93%), a total of 324 embolic lesions were detected in DWI representing 2.1% of the cumulated ischemic core volume. 151 peripheral emboli were detected in standard-resolution DWI, 173 additional emboli were uncovered in high-resolution DWI. Eight out of nine patients with an eTICI 3 reperfusion had embolic lesions (29 DWI lesions). 9.6% (31/324) of peripheral emboli were observed in vascular territories not affected by the LVO. SWI lesions were observed in close proximity to 10.2% (33/324) of DWI lesions.

Conclusions

Peripheral emboli are frequent after MT even after complete reperfusion. These emboli occur rather in the vascular territory of the occluded vessel than in other territories. A large proportion of peripheral emboli is only detected by high-resolution DWI.

Electronic supplementary material

The online version of this article (10.1007/s00415-020-09719-1) contains supplementary material, which is available to authorized users.

True First-Pass Effect

Background and Purpose- It has been hypothesized that in stroke patients, complete reperfusion (modified Thrombolysis in Cerebral Infarction; mTICI 3) after a single thrombectomy pass is a predictor for favorable outcome (modified Rankin Scale score, 0-2), but a true first-pass effect defined as improved clinical outcome after complete reperfusion with one versus multiple passes has not yet been specifically addressed in the literature. Methods- We compared clinical outcome of 164 consecutive patients with occlusions in the anterior circulation and known symptom onset, in whom we achieved complete reperfusion (mTICI 3), depending on whether complete reperfusion was achieved after a single thrombectomy pass (n=62) or multiple thrombectomy passes (n=102). To adjust for confounding factors such as prolonged time spans between symptom onset and reperfusion, additional administration of intra-arterial thrombolysis, and clot localization, we also compared clinical outcome of our first-pass group with a matched cohort (n=54) and a superselective subgroup of first-pass patients (only M1 occlusions, no additional intra-arterial thrombolysis; n=46) with its matched cohort (n=24). Results- Multivariable analysis of our cohort of 164 nonmatched patients revealed that there was a significant association between first-pass complete reperfusion and favorable clinical outcome (P=0.013). This was confirmed in our case-control analyses (P=0.010 and P=0.042). In our matched cohorts, favorable clinical outcome was seen almost twice as often if complete reperfusion was achieved after one pass (62% and 67% versus 36% and 37%), and odds for favorable outcome were 2.4 to 3.2× higher (CIs, 1.1-4.8 and 1.0-9.9). Conclusions- First-pass complete reperfusion is an independent factor for favorable outcome and should be aimed for in mechanical thrombectomy.