Endovascular therapy in the distal neurovascular territory: results of a large prospective registry

Endovascular thrombectomy for distal medium vessel occlusions: A literature review

BACKGROUND

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

OBJECTIVE

To summarize the current evidence regarding endovascular thrombectomy for DMVOs.

METHODS

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Multicenter evaluation of mechanical thrombectomy for distal medium vessel occlusions with National Institute of Health Stroke Scale Scores ≥ 6 and ≤ 6

BACKGROUND

While mechanical thrombectomy is considered standard of care for large vessel occlusions, scientific evidence to support treatment for distal and medium vessel occlusions remains scarce.

PURPOSE

To evaluate feasibility, safety, and outcomes in patients with low National Institute of Health Stroke Scale scores undergoing mechanical thrombectomy for treatment of distal medium vessel occlusions.

MATERIALS AND METHODS

Retrospective data review and analysis of prospectively maintained databases at 41 academic centers in North America, Asia, and Europe between January 2017 and January 2022. Characteristics and outcomes were compared between groups with low stroke scale score (≤ 6) versus and higher stroke scale scores (> 6). Propensity score matching using the optimal pair matching method and 1:1 ratio was performed.

RESULTS

Data were collected on a total of 1068 patients. After propensity score matching, there were a total of 676 patients included in the final analysis, with 338 patients in each group. High successful reperfusion rates were seen in both groups, 90.2% in ≤ 6 and 88.7% in the > 6 stroke scale groups. The frequency of excellent and good functional outcome was seen more common in low versus higher stroke scale score patients (64.5% and 81.1% versus 39.3% and 58.6%, respectively). The 90-day mortality rate observed in the ≤ 6 stroke scale group was 5.3% versus 13.3% in the > 6 stroke scale group.

CONCLUSION

Mechanical thrombectomy in distal and medium vessel occlusions, specifically in patients with low stroke scale scores is feasible, though it may not necessarily improve outcomes over IVT.

Feasibility and Clinical Outcome Predictors of Mechanical Thrombectomy in Distal Arterial Occlusion Causing Acute Ischemic Stroke: A Monocentric Retrospective Study

BACKGROUND

The feasibility and clinical outcome predictors of mechanical thrombectomy (MT) for strokes caused by distal arterial occlusion (DAO) remain the subject of debate.

METHODS

A retrospective analysis was conducted of patients with consecutive acute ischemic stroke treated using MT. Clinical and procedural-associated factors were studied to compare the efficacy, safety, and short-term and long-term outcomes of MT between the proximal arterial occlusion (PAO) and DAO groups. The predictors of a good functional outcome in the DAO group were also identified.

RESULTS

A total of 116 patients were included in this study, of whom 23 (19.8%) underwent MT for DAO. A higher complete recanalization rate was independently associated with PAO in adjusted models [adjusted odds ratio, 0.596; 95% CI, 0.377-0.941]. The measures of safety and clinical outcome showed no significant differences between the DAO and PAO groups. The National Institute of Health stroke scale (NIHSS) score on admission, hybrid technique use, and complete recanalization rate emerged as independent predictors of a good functional outcome in the DAO group.

CONCLUSIONS

The efficacy, safety, and short-term and long-term outcomes of DAO thrombectomy were similar to those of PAO thrombectomy. The good functional outcome predictors of MT in DAO included NIHSS on admission, hybrid technique use, and complete recanalization. Overall, the findings lead us to propose that MT may be considered a feasible option for treating DAO after a careful risk-benefit analysis.

Endovascular Versus Medical Management in Distal Medium Vessel Occlusion Stroke: The DUSK Study

BACKGROUND

Endovascular treatment (EVT) is part of the usual care for proximal vessel occlusion strokes. However, the safety and effectiveness of EVT for distal medium vessel occlusions remain unclear. We sought to compare the clinical outcomes of EVT to medical management (MM) for isolated distal medium vessel occlusions.

METHODS

This is a retrospective analysis of prospectively collected data from seven comprehensive stroke centers. Patients were included if they had isolated distal medium vessel occlusion strokes due to middle cerebral artery M3/M4, anterior cerebral artery A2/A3, or posterior cerebral artery P1/P2 segments. Patients treated with EVT or MM were compared with multivariable logistic regression and inverse probability of treatment weighting. The primary outcome was the shift in the degree of disability as measured by the modified Rankin Scale (mRS) at 90 days. Secondary outcomes included 90-day good (mRS score, 0-2) and excellent (mRS score, 0-1) outcomes. Safety measures included symptomatic intracranial hemorrhage and 90-day mortality.

RESULTS

A total of 321 patients were included in the analysis (EVT, 179; MM, 142; 40.8% treated with intravenous thrombolysis). In the inverse probability of treatment weighting model, there were no significant differences between EVT and MM in terms of the overall degree of disability (mRS ordinal shift; adjusted odds ratio [aOR], 1.25 [95% CI, 0.95-1.64]; P=0.110), rates of good (mRS score, 0-2; aOR, 1.32 [95% CI, 0.97-1.80]; P=0.075) and excellent (aOR, 1.32 [95% CI, 0.94-1.85]; P=0.098) outcomes, or mortality (aOR, 1.20 [95% CI, 0.78-1.85]; P=0.395) at 90 days. The multivariable regression model showed similar findings. Moreover, there was no difference between EVT and MM in rates of symptomatic intracranial hemorrhage in the multivariable regression model (aOR, 0.57 [95% CI, 0.21-1.58]; P=0.277), but the inverse probability of treatment weighting model showed a lower likelihood of symptomatic intracranial hemorrhage (aOR, 0.46 [95% CI, 0.24-0.85]; P=0.013) in the EVT group.

CONCLUSIONS

This multicenter study failed to demonstrate any significant outcome differences among patients with isolated distal medium vessel occlusions treated with EVT versus MM. These findings reinforce clinical equipoise. Randomized clinical trials are ongoing and will provide more definite evidence.

Endovascular therapy for posterior cerebral artery occlusion: systematic review with meta-analysis

Endovascular therapy (EVT) is a highly effective stroke treatment, but trials validating this intervention did not include patients with posterior cerebral artery (PCA) occlusion. The aim of this systematic review with meta-analysis was to assess the efficacy and safety of EVT for acute PCA occlusion. PubMed, Scopus, ISI, and CENTRAL were searched for studies assessing EVT in adult patients with PCA occlusion. Outcomes of interest were recanalization, symptomatic intracerebral haemorrhage (sICH), mortality, functional independence, and excellent functional outcome at 90 days. Frequencies and odds ratios (ORs) were pooled using random effect models and heterogeneity was measured using the I2 statistic and explored by means of meta-regression. Fifteen studies were included, all observational. Recanalization rates were high [81%, 95% CI (73-88%)] and sICH rates low [2%, 95% CI (1-4%)]. Heterogeneity was high for recanalization (I2 = 80%) but not for sICH, and not accounted for by any of the moderators tested. Compared to best medical treatment, EVT was associated with higher chances of sICH [OR = 2.04, 95% CI (1.12-3.71)] and no effect in functional independence [OR = 0.98, 95% CI (0.63-1.54)], with a tendency to higher chances of excellent functional outcome [OR = 1.29, 95% CI (0.90-1.86)] and mortality [OR = 1.56, 95% CI (0.84-2.90)]. EVT for acute PCA occlusion is technically feasible but associated with higher chance of sICH. There is no evidence to support this treatment to achieve higher rates of functional independence, but other gains that can impact patients' quality of life cannot be excluded. More studies are required with robust design, better patient selection, and comprehensive outcome evaluation.

Anesthesia modality in endovascular treatment for distal medium vessel occlusion stroke: intention-to-treat propensity score-matched analysis

BACKGROUND

The optimal anesthesia modality during endovascular treatment (EVT) for distal medium vessel occlusion (DMVO) stroke is uncertain. We aimed to evaluate the association of the anesthesia modality with procedural and clinical outcomes following EVT for DMVO stroke.

METHODS

This is a multicenter retrospective analysis of a prospectively collected database. Patients were included if they had DMVO involving the middle cerebral artery-M3/4, anterior cerebral artery-A2/3, or posterior cerebral artery-P1/P2-3, and underwent EVT. The cohort was divided into two groups, general anesthesia (GA) and non-general anesthesia (non-GA), and compared based on the intention-to-treat principle as primary analysis. We used propensity scores to balance the two groups. The primary outcome was the shift in the degree of disability as measured by the 90-day modified Rankin Scale (mRS). Secondary outcomes included successful reperfusion, as well as excellent (mRS 0-1) and good (mRS 0-2) clinical outcomes at 90 days. Safety measures included procedural complications, symptomatic intracerebral hemorrhage (sICH), and 90-day mortality.

RESULTS

Among 366 DMVO thrombectomies, 61 matched pairs were eligible for analysis. Median age and National Institutes of Health Stroke Scale score as well as other baseline demographic and clinical characteristics were balanced between both groups. The GA group had no difference in the overall degree of disability (common OR 1.19, 95% CI 0.52 to 2.86, P=0.67) compared with the non-GA arm. Likewise, the GA group had comparable rates of successful reperfusion (OR 2.38, 95% CI 0.80 to 7.07, P=0.12), good/excellent clinical outcomes (OR 1.14, 95% CI 0.44 to 2.96, P=0.79/(OR 0.65, 95% CI 0.24 to 1.81, P=0.41), procedural complications (OR 1.00, 95% CI 0.19 to 5.16, P>0.99), sICH (OR 3.24, 95% CI 0.83 to 12.68, P=0.09), and 90-day mortality (OR 1.43, 95% CI 0.48 to 4.27, P=0.52) compared with the non-GA group.

CONCLUSIONS

In patients with DMVO, our study showed that GA and non-GA groups had similar procedural and clinical outcomes, as well as safety measures. Further larger controlled studies are warranted.

Distal Medium Vessel Occlusion Strokes: Understanding the Present and Paving the Way for a Better Future

Distal medium vessel occlusions (DMVOs) are thought to cause as many as 25% to 40% of all acute ischemic strokes and may result in substantial disability amongst survivors. Although intravenous thrombolysis (IVT) is more effective for distal than proximal vessel occlusions, the overall efficacy of IVT remains limited in DMVO with less than 50% of patients achieving reperfusion and about 1/3 to 1/4 of the patients failing to achieve functional independence. Data regarding mechanical thrombectomy (MT) among these patients remains limited. The smaller, thinner, and more tortuous vessels involved in DMVO are presumably associated with higher procedural risks whereas a lower benefit might be expected given the smaller amount of tissue territory at risk. Recent advances in technology have shown promising results in endovascular treatment of DMVOs with room for future improvement. In this review, we discuss some of the key technical and clinical considerations in DMVO treatment including the anatomical and clinical terminology, diagnostic modalities, the role of IVT and MT, existing technology, and technical challenges as well as the contemporary evidence and future treatment directions.

Reperfusion strategies in stroke with medium-to-distal vessel occlusion: a prospective observational study

INTRODUCTION

Medium vessel occlusion (MeVO) accounts for 30% of acute ischemic stroke cases. The risk/benefit profile of endovascular thrombectomy (EVT) and intravenous thrombolysis (IVT) or the combination of the two (bridging therapy (BT)) is still unclear in MeVO. Here, we compare reperfusion strategies in MeVO for clinical and radiological outcomes.

METHODS

This prospective single center study enrolled consecutive patients with AIS due to primary MeVO undergoing IVT, EVT, or BT at a comprehensive stroke center. Primary outcome was good functional status, defined as modified Rankin Scale (mRS) 0-2 at 3-month follow-up. Additional outcomes included mortality, successful recanalization, defined as mTICI ≥ 2b, stroke severity at discharge, and symptomatic intracerebral hemorrhage (sICH) according to SITS-MOST criteria. Logistic regression was modeled to define independent predictors of the primary outcome.

RESULTS

Overall, 180 consecutive people were enrolled (IVT = 59, EVT = 38, BT = 83), mean age 75. BT emerged as independent predictor of primary outcome (OR = 2.76, 95% CI = 1.08-7.07) together with age (OR = 0.94, 95% CI = 0.9-0.97) and baseline NIHSS (OR = 0.88, 95% CI = 0.81-0.95). BT associated with a 20% relative increase in successful recanalization compared to EVT (74.4 vs 56.4%, p = 0.049). Rates of sICH (1.1%) and procedural complications (vasospasm 4.1%, SAH in 1.7%) were very low, with no difference across groups.

DISCUSSION

BT may carry a higher chance of good functional outcome compared to EVT/IVT only in people with AIS due to MeVO, with marginally higher rates of successful recanalization. Randomized trials are needed to define optimal treatment tailoring for MeVO.

Mechanical thrombectomy for the treatment of primary and secondary distal medium-vessel occlusion stroke: systematic review and meta-analysis

BACKGROUND

There is limited evidence on the indication and role of mechanical thrombectomy (MT) in patients with distal medium-vessel occlusions (DMVOs). The aim of this systematic review and meta-analysis was to evaluate all the evidence available on the efficacy and safety of MT techniques (stent retriever, aspiration) in primary and secondary DMVOs.

METHODS

Five databases were searched from inception to January 2023 for studies of MT in primary and secondary DMVOs. Outcomes of interest included favorable functional outcome (90-day modified Rankin scale (mRS) 0-2), successful reperfusion (modified Thrombolysis in Cerebral Infarction (mTICI) 2b-3), symptomatic intracerebral hemorrhage (sICH), and 90-day mortality. Prespecified subgroup meta-analyses according to the specific MT technique and to the vascular territory (distal M2-M5, A2-A5, P2-P5) were also performed.

RESULTS

A total of 29 studies with 1262 patients were included. For primary DMVOs (n=971 patients), pooled rates of successful reperfusion, favorable outcome, 90-day mortality and sICH were 84% (95% confidence interval (CI) 76 to 90%), 64% (95% CI 54 to 72%), 12% (95% CI 8 to 18%), and 6% (95% CI 4 to 10%), respectively. For secondary DMVOs (n=291 patients), pooled rates of successful reperfusion, favorable outcome, 90-day mortality and sICH were 82% (95% CI 73 to 88%), 54% (95% CI 39 to 69%), 11% (95% CI 5 to 20%), and 3% (95% CI 1 to 9%), respectively. Subgroup analyses by MT technique and by vascular territory showed no differences in primary and secondary DMVOs.

CONCLUSION

Our findings suggest that MT using aspiration or stent retriever techniques appears to be effective and safe in primary and secondary DMVOs. However, given the level of evidence of our results, further confirmation in well-designed randomized controlled trials is needed.

Basilar tip morphology: impact on mechanical thrombectomy for acute distal basilar artery occlusion

BACKGROUND

The morphology of the basilar artery tip (BAT) varies between patients. The morphologic anatomy of the BAT could affect the efficacy of mechanical thrombectomy (MT).

METHODS

108 patients with acute distal basilar artery occlusion (dBAO) who underwent MT from January 2013 to December 2021 were retrospectively analyzed. These patients were divided into two groups based on their BAT morphology: those with symmetrical cranial or caudal fusion of the BAT (symmetric group) and those with asymmetrical fusion of the BAT (asymmetric group). Morphological variables and angiographic and clinical outcomes were compared between the two groups.

RESULTS

Of the 108 enrolled patients, 42 were in the asymmetric group. Compared with the symmetric group, the asymmetric group had significantly larger BAT diameter (mean 3.5±1.0 mm vs 4.3±1.1 mm, P=0.001) and basilar artery tip/trunk ratio (1.2±0.2 vs 1.7±0.2, P<0.001). The asymmetric group showed a significantly lower rate of complete reperfusion (71.2% vs 40.5%, P=0.002) and first pass effect (FPE) (51.5% vs 21.4%, P=0.002) than the symmetric group. The BAT asymmetry was an independent predictor of failed FPE (OR 0.299, 95% CI 0.098 to 0.918, P=0.035) and failed complete reperfusion (OR 0.275, 95% CI 0.087 to 0.873, P=0.029).

CONCLUSIONS

The efficacy of MT for dBAO differs according to the anatomic morphology of the BAT. The asymmetric BAT was frequently encountered in dBAO patients and was independently associated with a reduced likelihood of complete reperfusion and FPE.

Mechanical thrombectomy for the treatment of primary and secondary anterior cerebral artery occlusions: insights from STAR

BACKGROUND

The safety and efficacy of mechanical thrombectomy (MT) for the treatment of acute anterior cerebral artery (ACA) occlusions have not clearly been delineated. Outcomes may be impacted based on whether the occlusion is isolated to the ACA (primary ACA occlusion) or occurs in conjunction with other cerebral arteries (secondary).

METHODS

We performed a retrospective review of the multicenter Stroke Thrombectomy and Aneurysm (STAR) database. All patients with MT-treated primary or secondary ACA occlusions were included. Baseline characteristics, procedural outcomes, complications, and clinical outcomes were collected. Primary and secondary ACA occlusions were compared using the Mann-Whitney U test and Kruskal-Willis test for continuous variables and the χ2 test for categorical variables.

RESULTS

The study cohort comprised 238 patients with ACA occlusions (49.2% female, median (SD) age 65.6 (16.7) years). The overall rate of successful recanalization was 75%, 90-day good functional outcome was 23%, and 90-day mortality was 35%. There were 44 patients with a primary ACA occlusion and 194 patients with a secondary ACA occlusion. When adjusted for baseline variables, the rates of successful recanalization (68% vs 76%, P=0.27), 90-day good functional outcome (41% vs 19%, P=0.38), and mortality at 90 days (25% vs 38%, P=0.12) did not differ between primary and secondary ACA occlusion groups.

CONCLUSION

Clinical and procedural outcomes are similar between MT-treated primary and secondary ACA occlusions for select patients. Our findings demonstrate the need for established criteria to determine ideal patient and ACA stroke characteristics amenable to MT treatment.

Outcomes with Endovascular Treatment of Patients with M2 Segment MCA Occlusion in the Late Time Window

BACKGROUND AND PURPOSE

Randomized trials in the late window have demonstrated the efficacy and safety of endovascular thrombectomy in large-vessel occlusions. Patients with M2-segment MCA occlusions were excluded from these trials. We compared outcomes with endovascular thrombectomy in patients with M2-versus-M1 occlusions presenting 6-24 hours after symptom onset.

MATERIALS AND METHODS

Analyses were on pooled data from studies enrolling patients with stroke treated with endovascular thrombectomy 6-24 hours after symptom onset. We compared 90-day functional independence (mRS ≤ 2), mortality, symptomatic intracranial hemorrhage, and successful reperfusion (expanded TICI = 2b-3) between patients with M2 and M1 occlusions. The benefit of successful reperfusion was then assessed among patients with M2 occlusion.

RESULTS

Of 461 patients, 367 (79.6%) had M1 occlusions and 94 (20.4%) had M2 occlusions. Patients with M2 occlusions were older and had lower median baseline NIHSS scores. Patients with M2 occlusion were more likely to achieve 90-day functional independence than those with M1 occlusion (adjusted OR = 2.13; 95% CI, 1.25-3.65). There were no significant differences in the proportion of successful reperfusion (82.9% versus 81.1%) or mortality (11.2% versus 17.2%). Symptomatic intracranial hemorrhage risk was lower in patients with M2-versus-M1 occlusions (4.3% versus 12.2%, P = .03). Successful reperfusion was independently associated with functional independence among patients with M2 occlusions (adjusted OR = 2.84; 95% CI, 1.11-7.29).

CONCLUSIONS

In the late time window, patients with M2 occlusions treated with endovascular thrombectomy achieved better clinical outcomes, similar reperfusion, and lower symptomatic intracranial hemorrhage rates compared with patients with M1 occlusion. These results support the safety and benefit of endovascular thrombectomy in patients with M2 occlusions in the late window.

Complete recanalization predicts favorable outcome in patients with distal M2-M3 middle cerebral artery occlusions following endovascular thrombectomy

BACKGROUND

- scanty articles illustrate the prognostic factors for favorable outcome after endovascular thrombectomy (EVT) in distal vessel occlusion (DMVO). Moreover, the current literature is diversified; conglomerating both primary, secondary, and anterior, posterior circulations embolic strokes in the same shell.

PURPOSE

to identify the association between complete reperfusion and favorable outcome following EVT for DMVO in the middle cerebral artery (MCA) territory.

METHODS

-we performed a retrospective analysis of prospectively maintained EVT registries at two comprehensive stroke centers between January 2015 and December 2019 for consecutive stroke patients with MCA-DMVO. DMVO was defined as an occlusion of distal M2 and M3 segments of the MCA. Only patients with primary isolated occlusions were included. A multivariate logistic regression was utilized to identify clinical and procedural-related factors associated with the 90-day favorable clinical outcome [defined as modified Rankin score (mRS) 0-2] after EVT.

RESULTS

-Out of 1823 within the registries; 66 patients (median age was 72 (60-78) and 59% were males) with primary isolated DMVO of the MCA were eligible for inclusion in the current study. Complete reperfusion was achieved in 56% (37/66) of the patients with no difference among the reperfusion strategies while the favorable outcome was observed in 68% (45/66). In the multivariate analysis, final complete reperfusion [modified Thrombolysis In Cerebral Infarction (mTICI) score 2c-3] was significantly associated with favorable outcome [aOR=7.69; (95% CI 1.73-34.17); p=.01], while higher baseline NIHSS score [aOR=0.82; (95% CI 0.69-0.98); p=.03] and increased imaging to puncture interval [aOR=0.99; (95% CI 0.98, 1.00); p=.01] decreased the probability of the favorable outcome.

CONCLUSION

according to our results, complete reperfusion was the most significant predictor of the favorable outcome, while higher baseline NIHSS and longer imaging to puncture interval decreased the probability of the favorable outcome.

Risk factors of hemorrhagic transformation in acute ischaemic stroke: A systematic review and meta-analysis

Background

Hemorrhagic transformation (HT) following reperfusion therapies for acute ischaemic stroke often predicts a poor prognosis. This systematic review and meta-analysis aims to identify risk factors for HT, and how these vary with hyperacute treatment [intravenous thrombolysis (IVT) and endovascular thrombectomy (EVT)].

Methods

Electronic databases PubMed and EMBASE were used to search relevant studies. Pooled odds ratio (OR) with 95% confidence interval (CI) were estimated.

Results

A total of 120 studies were included. Atrial fibrillation and NIHSS score were common predictors for any intracerebral hemorrhage (ICH) after reperfusion therapies (both IVT and EVT), while a hyperdense artery sign (OR = 2.605, 95% CI 1.212-5.599, I ² = 0.0%) and number of thrombectomy passes (OR = 1.151, 95% CI 1.041-1.272, I ² = 54.3%) were predictors of any ICH after IVT and EVT, respectively. Common predictors for symptomatic ICH (sICH) after reperfusion therapies were age and serum glucose level. Atrial fibrillation (OR = 3.867, 95% CI 1.970-7.591, I ² = 29.1%), NIHSS score (OR = 1.082, 95% CI 1.060-1.105, I ² = 54.5%) and onset-to-treatment time (OR = 1.003, 95% CI 1.001-1.005, I ² = 0.0%) were predictors of sICH after IVT. Alberta Stroke Program Early CT score (ASPECTS) (OR = 0.686, 95% CI 0.565-0.833, I ² =77.6%) and number of thrombectomy passes (OR = 1.374, 95% CI 1.012-1.866, I ² = 86.4%) were predictors of sICH after EVT.

Conclusion

Several predictors of ICH were identified, which varied by treatment type. Studies based on larger and multi-center data sets should be prioritized to confirm the results.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=268927, identifier: CRD42021268927.

Mechanical Thrombectomy for the Treatment of Anterior Cerebral Artery Occlusion: A Systematic Review of the Literature

BACKGROUND

The overall safety and efficacy of mechanical thrombectomy for anterior cerebral artery strokes remain unclear.

PURPOSE

Our aim was to summarize procedural and clinical outcomes in patients who underwent mechanical thrombectomy for treatment of anterior cerebral artery ischemic stroke.

DATA SOURCES

A systematic literature review was performed using PubMed, Ovid MEDLINE, and the Web of Science from inception until March 4, 2022.

STUDY SELECTION

We identified 9 studies with a total of 168 patients with mechanical thrombectomy-treated anterior cerebral artery occlusions.

DATA ANALYSIS

Recanalization, procedural data, and clinical outcome at last follow-up were collected and summarized. Categoric variables were reported as proportions. The χ² test of independence or the Kruskal-Wallis test was performed to assess the relationship between selected variables and the anterior cerebral artery embolus type (ie, primary isolated anterior cerebral artery, primary combined anterior cerebral artery, and secondary anterior cerebral artery occlusion) or the mechanical thrombectomy technique.

DATA SYNTHESIS

For mechanical thrombectomy-treated anterior cerebral artery occlusions, recanalization modified TICI 2b/3 was achieved in 80%, postprocedural complications occurred in 17% of patients, and the 90-day mortality rate was 19%. The rate of symptomatic intracranial hemorrhage varied depending on the anterior cerebral artery embolus type (χ² = 8.45, P = .01).

LIMITATIONS

This analysis did not consider factors such as small-study effects that affect reliability and limit interpretation.

CONCLUSIONS

Mechanical thrombectomy for the treatment of anterior cerebral artery occlusions is safe and efficacious, offering a favorable rate of recanalization and procedural complications. Mechanical thrombectomy-treated anterior cerebral artery occlusions appear to have lower rates of short-term good functional outcomes and an increased risk of symptomatic intracerebral hemorrhage compared with mechanical thrombectomy-treated MCA/ICA occlusions. Single and multicenter studies are needed to further examine the safety and efficacy of mechanical thrombectomy-treated anterior cerebral artery occlusions.

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.

CT Perfusion Maps Improve Detection of M2-MCA Occlusions in Acute Ischemic Stroke

OBJECTIVES

Middle cerebral artery occlusions, particularly M2 branch occlusions are challenging to identify on CTA. We hypothesized that additional review of the CTP maps will increase large vessel occlusion (LVO) detection accuracy on CTA and reduce interpretation time.

MATERIALS AND METHODS

Two readers (R1 and R2) retrospectively reviewed the CT studies in 99 patients (27 normal, 26 M1-MCA, 46 M2-MCA occlusions) who presented with suspected acute ischemic stroke (AIS). The time of interpretation and final diagnosis were recorded for the CTA images (derived from CTP data), both without and with the CTP maps. The time for analysis for all vascular occlusions was compared using McNemar tests. ROC curve analysis and McNemar tests were performed to assess changes in diagnostic performance with the addition of CTP maps.

RESULTS

With the addition of the CTP maps, both readers showed increased sensitivity (p = 0.01 for R1 and p = 0.04 for R2), and accuracy (p = 0.02 for R1 and p = 0.004 for R2) for M2-MCA occlusions. There was a significant improvement in diagnostic performance for both readers for detection of M2-MCA occlusions (AUC R1 = 0.86 to 0.95, R2 = 0.84 to 0.95; p < 0.05). Both readers showed reduced interpretation time for all cases combined, as well as for normal studies (p < 0.001) when CTP images were reviewed along with CTA. Both readers also showed reduced interpretation time for M2-MCA occlusions, which was significant for one of the readers (p < 0.02).

CONCLUSION

The addition of CTP maps improves accuracy and reduces interpretation time for detecting LVO and M2-MCA occlusions in AIS. Incorporation of CTP in acute stroke imaging protocols may improve detection of more distal occlusions.

Endovascular Therapy versus No Endovascular Therapy in Patients receiving Best Medical Management for Acute Isolated Occlusion of the Posterior Cerebral Artery: Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Endovascular therapy (EVT) is increasingly reported for treatment of isolated posterior cerebral artery (PCA) occlusions although its clinical benefit remains uncertain. This study-level meta-analysis investigated functional outcome and safety of EVT and best medical management (BMM) compared to BMM for treatment of PCA occlusion stroke.

METHODS

We conducted a literature search in PubMed, Web of Science and Embase for articles reporting patients with isolated PCA occlusion stroke treated with EVT+BMM or BMM including intravenous thrombolysis. There were no randomized trials and all studies were retrospective. Primary outcome was a modified Rankin Scale score of 0-2 at 3 months; safety outcomes included mortality rate and incidence of symptomatic intracranial hemorrhage.

RESULTS

Twelve articles with a total of 679 patients were included in the meta-analysis consisting of 338 patients with EVT+BMM and 341 patients receiving BMM alone. Good functional outcome at 3 months was achieved in 58.0% [95% confidence interval (CI) 43.83-70.95] of patients with EVT+BMM and 48.1% [95% CI 40.35-55.92] of patients with BMM with respective mortality rates of 12.6% [7.30-20.93] and 12.3% [8.64-17.33]. Symptomatic intracranial hemorrhage occurred in 4.2% [95% CI 2.47-7.03] of patients with EVT+BMM and 3.2% [95% CI 1.75-5.92] of patients with BMM. Comparative analyses were performed of publications reporting both treatments and demonstrated no significant differences.

CONCLUSIONS

The results demonstrate that EVT represents a safe treatment for patients with isolated PCA occlusion stroke. There were no differences in clinical or safety outcomes between treatments, supporting randomization of future patients into distal vessel occlusion trials.

Endovascular Thrombectomy for Distal Medium Vessel Occlusions of the Middle Cerebral Artery: A Safe and Effective Procedure

BACKGROUND

Distal medium vessel occlusions (DMVOs) are increasingly recognized as a next target for endovascular thrombectomy (EVT). Our objective was to investigate safety and clinical outcomes of EVT for DMVO of the middle cerebral artery (MCA).

METHODS

We analyzed data of the Lille Reperfusion Registry from January 2017 to September 2020. Patients with a primary or secondary DMVO of the MCA seen on pretreatment angiogram were included. Only patients with a eTICI score 2b50-2b67 on initial angiogram were considered. Baseline characteristics, angiographic clinical, and safety outcomes were compared between patients treated with EVT or standard medical treatment (no-EVT).

RESULTS

Of the 171 patients included, 96 received EVT (46.9% male, 68.7 ± 15.8 years) and 75 received standard medical treatment (44% male, 73.9 ± 13.1 years). EVT patients had a better improvement of the NIHSS score at discharge (adjusted mean difference: 3.71; 95% CI: 1.18-6.24). In the distal M2 occlusions subgroup, EVT was significantly associated with a higher rate of early neurologic improvement (adjusted OR: 3.62 95% CI: 1.31-10.03), NIHSS improvement at discharge (adjusted mean difference: 5.23; 95% CI: 2.18-8.29), and improved modified Rankin Scale score at 3 months (adjusted common OR for 1 point improvement: 3.06; 95% CI: 1.30 to 7.23). Symptomatic intracranial hemorrhage occurred in 3.1% in the EVT group and in 9.5% in the no-EVT group.

CONCLUSIONS

EVT for DMVO of the MCA appears to be safe and may lead to improved clinical outcomes. This effect was especially pronounced in patients with distal M2 occlusions, warranting randomized trials to validate this result.

Mechanical Thrombectomy for Distal Occlusions: Efficacy, Functional and Safety Outcomes: Insight from the STAR Collaboration

BACKGROUND

Mechanical thrombectomy (MT) is the standard of care for the treatment of proximal anterior circulation large vessel occlusions. However, little is known about its efficacy and safety in the treatment of distal intracranial occlusions.

METHODS

This is a multicenter retrospective study of patients treated with MT at 15 comprehensive centers between January 2015 and December 2018. The study cohort was divided into 2 groups based on the location of occlusion (proximal vs. distal). Distal occlusion was defined as occlusion of M3 segment of the middle cerebral artery, any segment of the anterior cerebral artery, or any segment of the posterior cerebral artery. Only isolated distal occlusion was included. Good outcome was defined as 90-day modified Rankin scale score 0-2.

RESULTS

A total of 4710 patients were included in this study, of whom 189 (4%) had MT for distal occlusions. Compared with the proximal occlusion group, distal occlusion group had a higher rate of good outcome (45% vs. 36%; P = 0.03) and a lower rate of successful reperfusion (78% vs. 84%; P = 0.04). However, the differences did not retain significance in adjusted models. Otherwise there was no difference in the rate of hemorrhagic complications, mortality, or procedure-related complications between the 2 groups. Successful reperfusion, age, and admission stroke severity emerged as predictors of good functional outcome in the distal occlusion group.

CONCLUSIONS

Thrombectomies of distal vessels achieve high rate of successful reperfusion with similar safety profile to those in more proximal locations.

New Class of Radially Adjustable Stentrievers for Acute Ischemic Stroke: Primary Results of the Multicenter TIGER Trial

Supplemental Digital Content is available in the text.

Background and Purpose:

The Tigertriever is a novel, radially adjustable, fully visible, stentriever that permits the operator to align radial expansion with target vessel diameters. This multicenter trial compared the Tigertriever’s effectiveness and safety compared with established stent retrievers.

Methods:

Single arm, prospective, multicenter trial comparing the Tigertriever to efficacy and safety performance goals derived from outcomes in 6 recent pivotal studies evaluating the Solitaire and Trevo stent-retriever devices with a lead-in and a main-study phase. Patients were enrolled if they had acute ischemic stroke with National Institutes of Health Stroke Scale score ≥8 due to large vessel occlusion within 8 hours of onset. The primary efficacy end point was successful reperfusion, defined as core laboratory-adjudicated modified Thrombolysis in Cerebral Ischemia score 2b-3 within 3 passes of the Tigertriever. The primary safety end point was a composite of 90-day all-cause mortality and symptomatic intracranial hemorrhage. Secondary efficacy end points included 3-month good clinical outcome (modified Rankin Scale score 0–2) and first-pass successful reperfusion.

Results:

Between May 2018 and March 2020, 160 patients (43 lead-in, 117 main phase) at 17 centers were enrolled and treated with the Tigertriever. The primary efficacy end point was achieved in 84.6% in the main-study phase group compared with the 63.4% performance goal and the 73.4% historical rate (noninferiority P<0.0001; superiority P<0.01). The first pass successful reperfusion rate was 57.8%. After all interventions, successful reperfusion (modified Thrombolysis in Cerebral Ischemia score ≥2b) was achieved in 95.7% and excellent reperfusion (modified Thrombolysis in Cerebral Ischemia score 2c-3) in 71.8%. The primary safety composite end point rate of mortality and symptomatic intracranial hemorrhage was 18.1% compared with the 30.4% performance goal and the 20.4% historical rate (noninferiority P=0.004; superiority P=0.57). Good clinical outcome was achieved in 58% at 90 days.

Conclusions:

The Tigertriever device was shown to be highly effective and safe compared with Trevo and Solitaire devices to remove thrombus in patients with large-vessel occlusive stroke eligible for mechanical thrombectomy.

Registration:

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03474549.