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

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

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

Assessment of Thrombectomy versus Combined Thrombolysis and Thrombectomy in Patients with Acute Ischemic Stroke and Medium Vessel Occlusion

Background The combination of intravenous thrombolysis (IVT) with mechanical thrombectomy (MT) may have clinical benefits for patients with medium vessel occlusion. Purpose To examine whether MT combined with IVT is associated with different outcomes than MT alone in patients with acute ischemic stroke (AIS) and medium vessel occlusion. Materials and Methods This retrospective study included consecutive adult patients with AIS and medium vessel occlusion treated with MT or MT with IVT at 37 academic centers in North America, Asia, and Europe. Data were collected from September 2017 to July 2021. Propensity score matching was performed to reduce confounding. Univariable and multivariable logistic regression analyses were performed to test the association between the addition of IVT treatment and different functional and safety outcomes. Results After propensity score matching, 670 patients (median age, 75 years [IQR, 64-82 years]; 356 female) were included in the analysis; 335 underwent MT alone and 335 underwent MT with IVT. Median onset to puncture (350 vs 210 minutes, P < .001) and onset to recanalization (397 vs 273 minutes, P < .001) times were higher in the MT group than the MT with IVT group, respectively. In the univariable regression analysis, the addition of IVT was associated with higher odds of a modified Rankin Scale (mRS) score 0-2 (odds ratio [OR], 1.44; 95% CI: 1.06, 1.96; P = .019); however, this association was not observed in the multivariable analysis (OR, 1.37; 95% CI: 0.99, 1.89; P = .054). In the multivariable analysis, the addition of IVT also showed no evidence of an association with the odds of first-pass effect (OR, 1.27; 95% CI: 0.9, 1.79; P = .17), Thrombolysis in Cerebral Infarction grades 2b-3 (OR, 1.64; 95% CI: 0.99, 2.73; P = .055), mRS scores 0-1 (OR, 1.27; 95% CI: 0.91, 1.76; P = .16), mortality (OR, 0.78; 95% CI: 0.49, 1.24; P = .29), or intracranial hemorrhage (OR, 1.25; 95% CI: 0.88, 1.76; P = .21). Conclusion Adjunctive IVT may not provide benefit to MT in patients with AIS caused by distal and medium vessel occlusion. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Wojak in this issue.

Endovascular thrombectomy versus medical management for moderate-to-severe anterior cerebral artery occlusion stroke

BACKGROUND

There are no established patient selection criteria for endovascular thrombectomy (EVT) for anterior cerebral artery (ACA) stroke.

METHODS

This was a retrospective cohort study of the 2016-2020 National Inpatient Sample in the United States. Isolated ACA-occlusion stroke patients with moderate-to-severe stroke symptoms (NIH stroke scale [NIHSS] ≥ 6) were included. Primary outcome was hospital discharge to home with self-care. Secondary outcomes include in-hospital mortality and intracranial hemorrhage (ICH). Confounders were accounted for by multivariable logistic regression.

RESULTS

6685 patients were included; 335 received EVT. Compared to medical management (MM), EVT patients were younger (mean 67.2 versus 72.2 years; p = 0.014) and had higher NIHSS (mean 16.0 versus 12.5; p < 0.001). EVT was numerically but not statistically significantly associated with higher odds of home discharge compared to MM (aOR 2.26 [95%CI 0.99-5.17], p = 0.053). EVT was significantly associated with higher odds of home discharge among patients with NIHSS 10 or greater (aOR 3.35 [95%CI 1.06-10.58], p = 0.039), those who did not receive prior thrombolysis (aOR 3.96 [95%CI 1.53-10.23], p = 0.005), and those with embolic stroke etiology (aOR 4.03 [95%CI 1.21-13.47], p = 0.024). EVT was not significantly associated with higher rates of mortality (aOR 1.93 [95%CI 0.80-4.63], p = 0.14); however, it was significantly associated with higher rates of ICH (22.4% vs. 8.5%, p < 0.001).

CONCLUSION

EVT was associated with higher odds of favorable short-term outcomes for moderate-to-severe ACA-occlusion stroke in select patients. Future studies are needed to confirm the efficacy of EVT in terms of longer term neurological outcomes.

Impact of demographic and clinical factors on in-hospital delays in acute ischemic stroke treatment

BACKGROUND

Delays in reperfusion treatment, both intravenous thrombolysis (IVT) and endovascular treatment (EVT), adversely affect outcomes in patients with acute ischemic stroke (AIS). To alleviate these delays, it is essential to comprehend how patients' baseline and stroke characteristics impact in-hospital reperfusion delays. While demographic and socioeconomic factors affect stroke outcomes, their impact on in-hospital delays remains unclear.

METHOD

This is retrospective analysis at a tertiary stroke center, encompassing AIS patients receiving IVT and / or EVT between 2019 and 2022 (re-canalization cohort). Outcomes of interest were time intervals of admission to CT and admission to recanalization. Univariable analyses explored age, gender, baseline functional status, socioeconomic status (SES), ethnicity, vascular risk factors, and stroke characteristics. Subsequently, multivariable logistic regression analyses were performed.

RESULTS

Altogether, 313 patients treated with IVT and 293 with EVT were included in the re-canalization cohort. No demographic variables were found to be associated with stroke treatment time intervals. Following multivariable analysis, stroke severity (low NIHSS, p < 0.01), arrival to the hospital by other means than ambulance (p < 0.01), and atypical stroke symptoms (p < 0.01), were associated with in-hospital delays, both in the EVT and the IVT groups.

CONCLUSION

Our findings indicate that patients with a more severe ischemic stroke, typical stroke symptoms, and arrival by ambulance have shorter stroke treatment time intervals. These results emphasize that, in atypical cases, even a lower suspicion of stroke should promote urgent workup for stroke diagnosis. Our findings do not indicate any influence of demographic or SES on in-hospital reperfusion delays.

Symptomatic intracerebral hemorrhage in proximal and distal medium middle cerebral artery occlusion patients treated with mechanical thrombectomy

BACKGROUND

Acute ischemic stroke (AIS) caused by distal medium vessel occlusions (DMVOs) represents a significant proportion of overall stroke cases. While intravenous thrombolysis (IVT) has been a primary treatment, advancements in endovascular procedures have led to increased use of mechanical thrombectomy (MT) in DMVO stroke patients. However, symptomatic intracerebral hemorrhage (sICH) remains a critical complication of AIS, particularly after undergoing intervention. This study aims to identify factors associated with sICH in DMVO stroke patients undergoing MT.

METHODS

This retrospective analysis utilized data from the Multicenter Analysis of Distal Medium Vessel Occlusions: Effect of Mechanical Thrombectomy (MAD-MT) registry, involving 37 centers across North America, Asia, and Europe. Middle cerebral artery (MCA) DMVO stroke patients were included. The primary outcome measured was sICH, as defined per the Heidelberg Bleeding Classification. Univariable and multivariable logistic regression were used to identify factors independently associated with sICH.

RESULTS

Among 1708 DMVO stroke patients, 148 (8.7%) developed sICH. Factors associated with sICH in DMVO patients treated with MT included older age (adjusted odds ratio (aOR) 1.01, 95% confidence interval (95% CI) 1.00 to 1.03, P=0.048), distal occlusion site (M3, M4) compared with medium occlusions (M2) (aOR 1.71, 95% CI 1.07 to 2.74, P=0.026), prior use of antiplatelet drugs (aOR 2.06, 95% CI 1.41 to 2.99, P<0.001), lower Alberta Stroke Program Early CT Scores (ASPECTS) (aOR 0.75, 95% CI 0.66 to 0.84, P<0.001), higher preoperative blood glucose level (aOR 1.00, 95% CI 1.00 to 1.01, P=0.012), number of passes (aOR 1.27, 95% CI 1.15 to 1.39, P<0.001), and successful recanalization (Thrombolysis In Cerebral Infarction (TICI) 2b-3) (aOR 0.43, 95% CI 0.28 to 0.66, P<0.001).

CONCLUSION

This study provides novel insight into factors associated with sICH in patients undergoing MT for DMVO, emphasizing the importance of age, distal occlusion site, prior use of antiplatelet drugs, lower ASPECTS, higher preoperative blood glucose level, and procedural factors such as the number of passes and successful recanalization. Pending confirmation, consideration of these factors may improve personalized treatment strategies.

Endovascular therapy versus best medical management in distal medium middle cerebral artery acute ischaemic stroke: a multinational multicentre propensity score-matched study

BACKGROUND

The efficacy of endovascular treatment (EVT) in acute ischaemic stroke due to distal medium vessel occlusion (DMVO) remains uncertain. Our study aimed to evaluate the safety and efficacy of EVT compared with the best medical management (BMM) in DMVO.

METHODS

In this prospectively collected, retrospectively reviewed, multicentre cohort study, we analysed data from the Multicentre Analysis of primary Distal medium vessel occlusions: effect of Mechanical Thrombectomy registry. Patients with acute ischaemic stroke due to DMVO in the M2, M3 and M4 segments who underwent EVT or received BMM were included. Primary outcome measures comprised 10 co-primary endpoints, including functional independence (mRS 0-2), excellent outcome (mRS 0-1), mortality (mRS 6) and haemorrhagic complications. Propensity score matching was employed to balance the cohorts.

RESULTS

Among 2125 patients included in the primary analysis, 1713 received EVT and 412 received BMM. After propensity score matching, each group comprised 391 patients. At 90 days, no significant difference was observed in achieving mRS 0-2 between EVT and BMM (adjusted OR 1.00, 95% CI 0.67 to 1.50, p>0.99). However, EVT was associated with higher rates of symptomatic intracerebral haemorrhage (8.4% vs 3.0%, adjusted OR 3.56, 95% CI 1.69 to 7.48, p<0.001) and any intracranial haemorrhage (37% vs 19%, adjusted OR 2.61, 95% CI 1.81 to 3.78, p<0.001). Mortality rates were similar between groups (13% in both, adjusted OR 1.48, 95% CI 0.87 to 2.51, p=0.15).

CONCLUSION

Our findings suggest that while EVT does not significantly improve functional outcomes compared with BMM in DMVO, it is associated with higher risks of haemorrhagic complications. These results support a cautious approach to the use of EVT in DMVO and highlight the need for further prospective randomised trials to refine treatment strategies.

Reliability assessment of distal occlusion eTICI scoring

BACKGROUND

The eThrombolysis in Cerebral Infarction (eTICI) score has been validated in proximal large artery occlusion (pLAOs). Despite the growing number of distal medium vessel occlusions (DMVOs) mechanical thrombectomies (MT) and the widespread utilization of the eTICI scoring system, its reliability and standardization for more distal occlusions have not been validated. We aim to evaluate the interrater reliability of eTICI scores in primary DMVOs.

METHODS

This was a retrospective analysis of a prospectively maintained database for consecutive patients with pLAO and DMVO MT at a single comprehensive stroke center from 2015 to 2022. Two fellowship-trained neurointerventionalists blindly/independently assessed digital subtraction angiograms for final eTICI, followed by consensus reads for discrepancies.

RESULTS

59 DMVO of 2248 thrombectomies [M3:29(50%)/M4:1(2%)/A1:3(5%)/A2:12(22%)/A3: 5(9%)/P1:7(12%)/P2:1(2%)] and 124 pLAOs of 308 thrombectomies [i-ICA:13(11%)/MCA-M1: 111(90%)] were included. The distribution of final eTICI scores was comparable between pLAO vs DMVOs (p = 0.82). The pLAO final eTICI score assessment between two readers demonstrated moderate reliability with a kappa0.77 (95%CI: 0.67-0.88), while the DMVO eTICI score assessment exhibited almost-perfect agreement with kappa 0.94 (95%CI: 0.90-0.99). The agreement between the consensus read and the original report in DMVOs was 0.86 (95% CI: 0.71-1.00) while for pLAO it was 0.83(95% CI: 0.76-0.90). The performance of eTICI was comparable amongst different DMVO territories as well as for distal vs. very distal occlusions.

CONCLUSION

eTICI score exhibited comparable performance for DMVO as compared to pLAO strokes. Further studies investigating DMVO eTICI grading and clinical outcomes are warranted.

Incidence, Risk Factors, and Clinical Implications of Subarachnoid Hyperdensities on Flat-Panel Detector CT following Mechanical Thrombectomy in Patients with Anterior Circulation Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Flat-panel detector CT immediately after mechanical thrombectomy can detect complications, including early hemorrhagic transformation and subarachnoid hyperdensities. The clinical significance of subarachnoid hyperdensities in patients undergoing mechanical thrombectomy remains unclear.

MATERIALS AND METHODS

We studied 223 patients who underwent mechanical thrombectomy for anterior circulation stroke who had flat-panel detector CT performed immediately after the procedure and had follow-up imaging within 24 hours. Subarachnoid hyperdensity severity was categorized into 5 grades (subarachnoid hyperdensities, 0: absent to subarachnoid hyperdensities, IV: extensive). Baseline and procedural characteristics as well as outcome measures were analyzed using group comparisons and multivariable logistic regression analyses.

RESULTS

Overall, 100/223 (45%) patients showed subarachnoid hyperdensities on immediate postinterventional flat-panel detector CT. The factors associated with an increased subarachnoid hyperdensity risk were the following: medium-vessel occlusion or distal-vessel occlusion compared with a large-vessel occlusion, a more distal device position, a higher number of device passes, a larger volume of contrast applied, worse final reperfusion expanded TICI, and after receiving IV thrombolysis. The occurrence of subarachnoid hyperdensity grades II-IV was independently associated with worse functional outcomes (adjusted OR for mRS, 3-6: 2.2; 95% CI 1.1-4.3), whereas patients with subarachnoid hyperdensity grade I had outcomes similar to those in patients without subarachnoid hyperdensities.

CONCLUSIONS

Our study identified risk factors for subarachnoid hyperdensities, most of which reflect increasingly challenging procedures or more peripheral recanalization attempts. The presence of subarachnoid hyperdensity grades II-IV was associated with poorer outcomes, suggesting the need for personalized strategies to reduce its incidence and severity or potentially improve recovery after subarachnoid hyperdensities.

Endovascular treatment of primary M3 occlusion stroke in clinical practice: analysis of the German Stroke Registry

BACKGROUND

Endovascular treatment (ET) options for acute stroke due to distal middle cerebral artery occlusions are rapidly evolving, but data on outcome and safety are sparse. We therefore performed an analysis of patients undergoing ET for primary M3 occlusions in routine clinical practice in a nationwide registry.

METHODS

Patients enrolled between 01/20 and 12/21 in the prospective, multicenter German Stroke Registry-Endovascular Treatment (GSR-ET) were screened for mechanical thrombectomy performed for primary M3 occlusion. We analyzed neurological deficit as measured by the National Institute of Health Stroke Scale (NIHSS), symptomatic intracranial hemorrhage (sICH), thrombectomy technique, successful reperfusion (modified Thrombolysis in Cerebral Infarction [mTICI] score of 2b-3) and functional outcome as measured by the modified Rankin Scale (mRS) at discharge and 90 days.

RESULTS

Out of 5574 patients, 11 patients (0.2%, median age 80 years, 54.5% female) underwent ET for primary M3 occlusion. All patients had pre-admission mRS ≤ 1, median NIHSS on admission was 8, and successful reperfusion was achieved in 6/11 patients (54.5%). While no vasospasm, dissection or perforation was reported, symptomatic intracranial hemorrhage occurred in 2 patients (18.2%). Favorable outcome (mRS ≤ 2) was achieved in 6/11 patients (54.5%) at 90-day follow-up.

CONCLUSIONS

ET for primary M3 occlusions is rarely performed. While technically feasible, the procedure's potential benefits must be carefully weighed against its associated risks, including clinically relevant complications. Caution and further research is needed to optimize patient selection for this intervention.

TRIAL REGISTRATION

GSR-ET; ClinicalTrials.gov Identifier: NCT03356392; Trial Registration Date: 11/29/2017.

Incidence and outcome of perforations during medium vessel occlusion compared with large vessel occlusion thrombectomy

BACKGROUND

Vessel perforation during thrombectomy is a severe complication and is hypothesized to be more frequent during medium vessel occlusion (MeVO) thrombectomy. The aim of this study was to compare the incidence and outcome of patients with perforation during MeVO and large vessel occlusion (LVO) thrombectomy and to report on the procedural steps that led to perforation.

METHODS

In this multicenter retrospective cohort study, data of consecutive patients with vessel perforation during thrombectomy between January 1, 2015 and September 30, 2022 were collected. The primary outcomes were independent functional outcome (ie, modified Rankin Scale 0-2) and all-cause mortality at 90 days. Binomial test, chi-squared test and t-test for unpaired samples were used for statistical analysis.

RESULTS

During 25 769 thrombectomies (5124 MeVO, 20 645 LVO) in 25 stroke centers, perforation occurred in 335 patients (1.3%; mean age 72 years, 62% female). Perforation occurred more often in MeVO thrombectomy (2.4%) than in LVO thrombectomy (1.0%, p<0.001). More MeVO than LVO patients with perforation achieved functional independence at 3 months (25.7% vs 10.9%, p=0.001). All-cause mortality did not differ between groups (overall 51.6%). Navigation beyond the occlusion and retraction of stent retriever/aspiration catheter were the two most common procedural steps that led to perforation.

CONCLUSIONS

In our cohort, perforation was approximately twice as frequent in MeVO than in LVO thrombectomy. Efforts to optimize the procedure may focus on navigation beyond the occlusion site and retraction of stent retriever/aspiration catheter. Further research is necessary in order to identify thrombectomy candidates at high risk of intraprocedural perforation and to provide data on the effectiveness of endovascular countermeasures.

Outcomes and differences by occluded vessel after endovascular thrombectomy for isolated medium vessel occlusions

BACKGROUND

The outcomes of endovascular thrombectomy (EVT) for medium vessel occlusions (MeVOs) of specific vascular territories remain unknown. We aimed to investigate EVT outcomes by MeVO locations using the data from an ongoing international multicenter registry.

METHODS

Patients with isolated MeVO who underwent EVT between January 2013 and December 2022 were retrospectively analyzed. Isolated MeVO was defined as an occlusion of the A2 or A3 (A2/A3), M2 or M3, and P2 or P3 (P2/P3). Outcomes included a 90-day modified Rankin score (mRS) of 0-2, successful recanalization (modified Thrombolysis in Cerebral Infarction score ≥ 2b), early neurological deterioration (END) or improvement (ENI), and 90-day mortality. END was defined as a worsening of ≥4 points from the baseline National Institutes of Health Stroke Scale (NIHSS) score within 24 h of EVT, while ENI was defined as an improvement of ≥4 points from the baseline NIHSS score within 24 h of EVT.

RESULTS

1744 MeVOs included. Compared to M2 occlusions (n = 1542, 88.4%), A2/A3 (n = 36, 2.1%) occlusions had lower odds of 90-day mRS 0-2 (adjusted odds ratio [aOR] 0.30, 95% confidence interval [CI] 0.11-0.80), and P2/P3 occlusions (n = 49, 2.8%) had lower odds of successful recanalization (aOR 0.19, 95% CI 0.07-0.50), and higher odds of END (aOR 3.53, 95% CI 1.35-9.25). Other outcomes showed no significant differences.

CONCLUSIONS

A2/A3 occlusions were more likely to have worse outcomes compared to M2 occlusions after EVT for patients with isolated MeVOs.

Review: Flow Diversion for the Treatment of Middle Cerebral Artery Aneurysms

The invention of flow diverting stents (FDS) is a novel milestone in the field of endovascular aneurysm therapy, promoting physiological healing of the vessel segment contrary to prior deconstructive treatment strategies, such as coiling. The effects of FDS are based on changes in flow patterns, segmental wall stabilization, and the growth of a neointima. Although flow diversion is already well established for cerebral aneurysms in proximal segments, peripheral locations remain challenging. Especially the middle cerebral artery (MCA) with its predominance of non-collateralized perforators and functional end arteries that supply the eloquent areas of the brain is of major concern.The literature was reviewed for flow diversion of the MCA and antiplatelet therapy.Resulting from the special anatomical characteristics of the MCA, FDS implantation in this territory is completely different from the proximal vessel segments. Still, flow diversion represents an effective endovascular strategy, especially in otherwise non-accessible or sufficiently treatable lesions. However, the risk of ischemic adverse events might be increased. Special attention to the individual decision regarding device selection, antiplatelet regimen, and exact definition of the proximal and distal landing zone considering the jailed side branches is essential for a good angiographic and clinical outcome. · MCA aneurysms can be sufficiently treated by FDS.. · The anatomic and hemodynamic characteristics of the MCA result in an increased risk of thromboembolism.. · Individual device selection and antiplatelet regimen are essential for treatment success.. · Schüngel M, Wohlgemuth WA, Elolf E et al. Review: Flow Diversion for the Treatment of Middle Cerebral Artery Aneurysms. Fortschr Röntgenstr 2024; DOI 10.1055/a-2343-0046.

Comparative Analysis of Mechanical Thrombectomy Outcomes of Middle Cerebral Artery M1, M2 Superior, and M2 Inferior Occlusion Strokes

BACKGROUND

The M1 middle cerebral artery (MCA) commonly bifurcates into M2 superior and M2 inferior segments. However, MCA anatomy is highly variable rendering classification for mechanical thrombectomy trials difficult. This study explored safety and effectiveness of M2 MCA stroke thrombectomy stratified by M2 MCA anatomy.

METHODS

Cases of large vessel occlusion strokes treated by mechanical thrombectomy between February 2016 and August 2022 were reviewed (N = 784). M1 (n = 431) and M2 (n = 118) MCA occlusions were assessed. Among M2 MCA occlusions, only prototypical MCA bifurcation anatomy cases were included (n = 99). Dominance was assessed based on angiography. Procedural and outcome data were compared between M1, M2 superior, and M2 inferior MCA occlusions.

RESULTS

Baseline demographics and periprocedural criteria of M2 superior (n = 56) and M2 inferior (n = 43) occlusion mechanical thrombectomies were comparable. The occluded branch was dominant in 41/43 (95.3%) M2 inferior cases, but in only 37/56 (66.1%) M2 superior cases (P < 0.001). The 90-day favorable functional outcome (modified Rankin Scale score 0-2) and mortality (modified Rankin Scale score 6) rates were 60.0% and 8.9% in M2 superior, 42.9% and 32.6% in M2 inferior, and 44.1% and 26.0% in M1 (n = 431) cases. Compared with M2 superior cases, in M2 inferior cases, favorable outcome rates were lower (P = 0.094) and mortality rates were higher (P = 0.003) and resembled M1 rates (P = 0.750 and P = 0.355, respectively).

CONCLUSIONS

In the setting of prototypical MCA bifurcation anatomy, thrombectomy of dominant M2 inferior occlusions had outcome rates similar to M1 occlusions. In contrast, M2 superior occlusions had significantly lower mortality rates and a trend toward better favorable functional outcome rates.

Hypoperfusion Intensity Ratio Is Associated with Early Neurologic Deficit Severity and Deterioration after Mechanical Thrombectomy in Large-Vessel Occlusion Ischemic Stroke

BACKGROUND AND PURPOSE

The hypoperfusion intensity ratio is a surrogate marker for collateral status and a predictor of infarct growth, malignant cerebral edema, and hemorrhagic transformation. Its utility to predict a poor NIHSS score and early neurologic deterioration after mechanical thrombectomy for large vessel (LVO) versus distal and medium vessel occlusions (DMVO) has not been investigated. The objective of this study was to determine whether the higher hypoperfusion intensity ratio is associated with a worse NIHSS score at 24 hours post-mechanical thrombectomy and early neurologic deterioration in LVO versus DMVO acute ischemic stroke.

MATERIALS AND METHODS

This was a retrospective study of 231 patients with acute ischemic stroke with LVO or DMVO amenable for mechanical thrombectomy and available CTP for hypoperfusion intensity ratio assessment pre-mechanical thrombectomy. Clinical and imaging characteristics were abstracted from the medical records. The primary outcome was the NIHSS score at 24 hours post-mechanical thrombectomy. The secondary outcome was early neurologic deterioration, defined as a >4-point increase in the NIHSS score between the initial assessment and 24 hours post-mechanical thrombectomy. All analyses were first conducted in the entire cohort and then separately for the LVO versus DMVO groups.

RESULTS

The optimal hypoperfusion intensity ratio threshold to detect early neurologic deterioration was 0.54. A hypoperfusion intensity ratio ≥ 0.54 was more frequently present in LVO versus DMVO (n = 37 [77.1%] versus n = 11 [22.9%]; P < .001). On multivariable linear regression, the hypoperfusion intensity ratio ≥ 0.54 was independently associated with a worse NIHSS score at 24 hours post-mechanical thrombectomy in the entire cohort (β = 0.163; P = .002) and the LVO group (β = 0.210; P = .005), but not in the DMVO group. The early neurologic deterioration occurred in 26 (11.3%) subjects. On multivariable logistic regression, there was no association of the hypoperfusion intensity ratio ≥ 0.54 with early neurologic deterioration in the entire cohort. However, when analyzed separately, a hypoperfusion intensity ratio ≥ 0.54 significantly increased the odds of early neurologic deterioration in subjects with LVO (OR = 5.263; 95% CI, 1.170-23.674; P = .030) but not in the DMVO group.

CONCLUSIONS

The hypoperfusion intensity ratio ≥ 0.54 was independently associated with a worse 24-hour post-mechanical thrombectomy NIHSS score and early neurologic deterioration in LVO, but not in DMVO acute ischemic stroke. Pending confirmation in future, prospective studies assessing the hypoperfusion intensity ratio may help identify patients at risk of secondary decline to improve peri-thrombectomy care and clinical decision-making.

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.

Endovascular Thrombectomy for Acute Ischemic Stroke : Current Concept in Management

Endovascular thrombectomy (EVT) has been established as the standard of care in the treatment of acute ischemic stroke (AIS) based on landmark randomized controlled trials. Nevertheless, while the strict eligibility of EVT for AIS patients restrict the wide application of EVT, a considerable population still undergoes off-label EVT. Besides, it is important to acknowledge that recanalization is not achieved in approximately 20% of procedures, and more than 50% of patients who undergo EVT still do not experience a favorable outcome. This article reviews the brief history of EVT trials and recent progressions in the treatment of AIS, with focusing on the expanding eligibility criteria, new target for EVT, and the evolution of EVT techniques.

Cervical Dissection in Patients With Tandem Lesions Is Associated With Distal Embolism and Lower Recanalization Success

BACKGROUND

Tandem lesions consist of cervical internal carotid artery (ICA) stenosis or occlusion, most commonly of atherosclerosis or dissection etiology, plus a large vessel occlusion. In this study, we compare outcomes in patients with atherosclerosis versus dissection of the cervical ICA.

METHODS

This multicenter retrospective cohort study includes data from tandem lesion patients who underwent endovascular treatment from 2015 to 2020. Atherosclerosis was defined as ICA stenosis/occlusion associated with a calcified lesion and dissection by the presence of a tapered or flame-shaped lesion and intramural hematoma. Primary outcome: 90-day functional independence (modified Rankin Scale score, 0-2); secondary outcomes: 90-day favorable shift in the modified Rankin Scale score, modified Thrombolysis in Cerebral Infarction score 2b-3, modified Thrombolysis in Cerebral Infarction score 2c-3, symptomatic intracranial hemorrhage, parenchymal hematoma type 2, petechial hemorrhage, distal embolization, early neurological improvement, and mortality. Analysis was performed with matching by inverse probability of treatment weighting.

RESULTS

We included 526 patients (68 [59-76] years; 31% females); 11.2% presented dissection and 88.8%, atherosclerosis. Patients with dissection were younger, had lower rates of hypertension, hyperlipidemia, diabetes, and smoking history. They also exhibited higher rates of ICA occlusion, multiple stents (>1), and lower rates of carotid self-expanding stents. After matching and adjusting for covariates, there were no differences in 90-day functional independence. The rate of successful recanalization was significantly lower in the dissection group (adjusted odds ratio, 0.38 [95% CI, 0.16-0.91]; P=0.031), which also had significantly higher rates of distal emboli (adjusted odds ratio, 2.53 [95% CI, 1.15-5.55]; P=0.021). There were no differences in other outcomes. Acute ICA stenting seemed to increase the effect of atherosclerosis in successful recanalization.

CONCLUSIONS

This study reveals that among patients with acute stroke with tandem lesions, cervical ICA dissection is associated with higher rates of distal embolism and lower rates of successful recanalization than atherosclerotic lesions. Using techniques to minimize the risk of distal embolism may mitigate this contrast. Further prospective randomized trials are warranted to fully understand these associations.

A one-dimensional computational model for blood flow in an elastic blood vessel with a rigid catheter

Strokes are one of the leading causes of death in the United States. Stroke treatment involves removal or dissolution of the obstruction (usually a clot) in the blocked artery by catheter insertion. A computer simulation to systematically plan such patient-specific treatments needs a network of about 105 blood vessels including collaterals. The existing computational fluid dynamic (CFD) solvers are not employed for stroke treatment planning as they are incapable of providing solutions for such big arterial trees in a reasonable amount of time. This work presents a novel one-dimensional mathematical formulation for blood flow modeling in an elastic blood vessel with a centrally placed rigid catheter. The governing equations are first-order hyperbolic partial differential equations, and the hypergeometric function needs to be computed to obtain the characteristic system of these hyperbolic equations. We employed the Discontinuous Galerkin method to solve the hyperbolic system and validated the implementation by comparing it against a well-established 3D CFD solver using idealized vessels and a realistic truncated arterial network. The results showed clinically insignificant differences in steady flow cases, with overall variations between 1D and 3D models remaining below 10%. Additionally, the solver accurately captured wave reflection phenomena at domain discontinuities in unsteady cases. A primary advantage of this model over 3D solvers is its ease in obtaining a discretized geometry of complex vasculatures with multiple arterial branches. Thus, the 1D computational model offers good accuracy and applicability in simulating complex vasculatures, demonstrating promising potential for investigating patient-specific endovascular interventions in strokes.

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.

Imaging features for the identification of atrial fibrillation in cryptogenic stroke patients

BACKGROUND

Whether specific imaging aspects can be used to identify cryptogenic stroke (CS) patients with high risk of underlying atrial fibrillation (AF) remains unclear. The purpose of this study was to evaluate brain-imaging features in CS patients and their utility as AF predictors.

METHODS

The Nordic Atrial Fibrillation and Stroke study was a prospective observational study of CS and transient ischemic attack patients undergoing 12-month cardiac-rhythm monitoring, biomarker and clinical assessments. In this imaging sub-study, brain magnetic resonance imaging and computed tomography scans from 106 patients were assessed for acute and chronic ischemic lesions in relation to AF occurrence and included in a score to predict AF. Receiver operating characteristics (ROC) curve was used to evaluate the discriminative ability of the score and for its dichotomization for predictive model.

RESULTS

Age, periventricular white-matter hyperintensities (PVWMH), acute lesion size, and vessel occlusion were significantly associated with AF. Acute and chronic cortical infarcts as well as chronic cerebellar infarcts were numerically more frequent in the AF group than the non-AF group. A score consisting of six features (0-6 points) was proposed (age ≥ 65 years, chronic cortical or cerebellar lesions, acute cortical lesions, PVWMH ≥ 2 in Fazekas scale, vessel occlusion, and acute lesion size ≥ 10 mm). Area under ROC curve was 0.735 and a score of ≥ 3 points was a predictor of AF.

CONCLUSIONS

The suggested score was shown to identify CS patients with an increased risk of underlying AF.

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

BACKGROUND AND OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Deep Learning-Based High-Resolution Magnetic Resonance Angiography (MRA) Generation Model for 4D Time-Resolved Angiography with Interleaved Stochastic Trajectories (TWIST) MRA in Fast Stroke Imaging

PURPOSE

The purpose of this study is to improve the qualitative and quantitative image quality of the time-resolved angiography with interleaved stochastic trajectories technique (4D-TWIST-MRA) using deep neural network (DNN)-based MR image reconstruction software.

MATERIALS AND METHODS

A total of 520 consecutive patients underwent 4D-TWIST-MRA for ischemic stroke or intracranial vessel stenosis evaluation. Four-dimensional DNN-reconstructed MRA (4D-DNR) was generated using commercially available software (SwiftMR v.3.0.0.0, AIRS Medical, Seoul, Republic of Korea). Among those evaluated, 397 (76.3%) patients received concurrent time-of-flight MRA (TOF-MRA) to compare the signal-to-noise ratio (SNR), image quality, noise, sharpness, vascular conspicuity, and degree of venous contamination with a 5-point Likert scale. Two radiologists independently evaluated the detection rate of intracranial aneurysm in TOF-MRA, 4D-TWIST-MRA, and 4D-DNR in separate sessions. The other 123 (23.7%) patients received 4D-TWIST-MRA due to a suspicion of acute ischemic stroke. The confidence level and decision time for large vessel occlusion were evaluated in these patients.

RESULTS

In qualitative analysis, 4D-DNR demonstrated better overall image quality, sharpness, vascular conspicuity, and noise reduction compared to 4D-TWIST-MRA. Moreover, 4D-DNR exhibited a higher SNR than 4D-TWIST-MRA. The venous contamination and aneurysm detection rates were not significantly different between the two MRA images. When compared to TOF-MRA, 4D-CE-MRA underestimated the aneurysm size (2.66 ± 0.51 vs. 1.75 ± 0.62, p = 0.029); however, 4D-DNR showed no significant difference in size compared to TOF-MRA (2.66 ± 0.51 vs. 2.10 ± 0.41, p = 0.327). In the diagnosis of large vessel occlusion, 4D-DNR showed a better confidence level and shorter decision time than 4D-TWIST-MRA.

CONCLUSION

DNN reconstruction may improve the qualitative and quantitative image quality of 4D-TWIST-MRA, and also enhance diagnostic performance for intracranial aneurysm and large vessel occlusion.

Identifying the Sylvian Triangle on CT angiography: A technique for detecting distal middle cerebral artery occlusions

Medium vessel occlusions (MeVOs), defined as occlusion of the M2/M3 and A2/A3 segments of the middle cerebral artery (MCA) and anterior cerebral artery, can be challenging to visualize on CT angiography (CTA) and MR angiography (MRA), given the anatomic complexity of the mid- and distal intracranial vasculature and smaller vessel caliber (Leary MC, Kidwell CS, Villablanca JP, et al. Validation of computed tomographic MCA "dot" sign: an angiographic correlation study. Stroke 2003; 34: 2636-2640; Luijten SPR, Wolff L, Duvekot MHC, et al. Diagnostic performance of an algorithm for automated large vessel occlusion (LVO) detection on CTA. J Neurointerv Surg 2022; 14: 794-798). In turn, the appearance of a sudden vessel cutoff in these vascular distributions on CTA or MRA is not always straightforward and may represent true occlusion, variant anatomy, and/or artifact (Leary MC, Kidwell CS, Villablanca JP, et al. Validation of computed tomographic MCA "dot" sign: an angiographic correlation study. Stroke 2003; 34: 2636-2640; Luijten SPR, Wolff L, Duvekot MHC, et al. Diagnostic performance of an algorithm for automated LVO detection on CTA. J Neurointerv Surg 2022; 14: 794-798). Given the importance of rapidly establishing an accurate diagnosis in the setting of stroke, combined with recent clinical trials and movements promoting the efficacy of endovascular therapeutic approaches to treat MeVOs, it remains imperative to detect such occlusions accurately and quickly on imaging. In turn, we present five imaging patterns of the Sylvian Triangle on sagittal reformatted images from CTA Head examinations, which our practice has utilized to assess patency of the M2 and M3 divisions. This approach is rapidly deployable and can be utilized by radiology and non-radiology healthcare providers alike, thus facilitating rapid and accurate diagnosis of MeVO, timely evaluation of candidacy for endovascular therapy, and ultimately supporting favorable door-to-intervention time and successful patient outcomes.

Distal mechanical thrombectomy using beveled tip aspiration zoom catheters: A preliminary study

INTRODUCTION

Distal medium vessel occlusion (DVO) thrombectomy has been shown to be efficacious with safety profiles comparable to large vessel occlusion (LVO) thrombectomy. A novel, highly-trackable, bevel-tipped Zoom 35 catheter can be used as an aspiration catheter for DVO thrombectomy.

METHODS

This is a retrospective, single-arm, multi-institutional observational study evaluating the efficacy and safety of aspiration thrombectomy for DVO using the Zoom 35 catheter. Patient demographics, presenting and discharge NIHSS, primary and rescue thrombectomy, site of occlusion, TICI score, and intracranial hemorrhage were chart abstracted. Descriptive statistics were used to evaluate the efficacy and safety of thrombectomy.

RESULTS

Fourteen patients (mean age 66.64 ± 13.75 years) were included. The mean NIHSS at presentation was 10.79 ± 5.48, and the mean ASPECTS was 9.00 ± 0.89. Nine patients (64.3%) received tPA. Primary occlusion location was M3 in nine cases (64.3%), M2/M3 junction in two cases (14.3%), A2 in one case (7.1%), A3 in one case (7.1%), and P1 in one case (7.1%). TICI scores were 3 in seven cases (50.0%), 2C in three cases (21.4%), and 2B in four cases (28.6%). There was one postoperative SAH (7.1%) and one asymptomatic ICH (7.1%). Mean discharge NIHSS was 3.38 ± 4.44, with a mean decrease of 7.31 from presentation (p < 0.0001, t-test).

CONCLUSION

Zoom 35 beveled-tip aspiration microcatheters are highly trackable and associated with improved radiographic and clinical outcomes for the treatment of DVO with a good safety profile.

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

INTRODUCTION

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05809921.

Pretreatment CTP Collateral Parameters Predict Good Outcomes in Successfully Recanalized Middle Cerebral Artery Distal Medium Vessel Occlusions

BACKGROUND/PURPOSE

Distal medium vessel occlusions (DMVOs) account for a large percentage of vessel occlusions resulting in acute ischemic stroke (AIS) with disabling symptoms. We aim to assess whether pretreatment quantitative CTP collateral status (CS) parameters can serve as imaging biomarkers for good clinical outcomes prediction in successfully recanalized middle cerebral artery (MCA) DMVOs.

METHODS

We performed a retrospective analysis of consecutive patients with AIS secondary to primary MCA-DMVOs who were successfully recanalized by mechanical thrombectomy (MT) defined as modified thrombolysis in cerebral infarction (mTICI) 2b, 2c, or 3. We evaluated the association between the CBV index and HIR independently with good clinical outcomes (modified Rankin score 0-2) using Spearman rank correlation, logistic regression, and ROC analyses.

RESULTS

From 22 August 2018 to 18 October 2022 8/22/2018 to 10/18/2022, 60 consecutive patients met our inclusion criteria (mean age 71.2 ± 13.9 years old [mean ± SD], 35 female). The CBV index (r = -0.693, p < 0.001) and HIR (0.687, p < 0.001) strongly correlated with 90-day mRS. A CBV index ≥ 0.7 (odds ratio, OR, 2.27, range 6.94-21.23 [OR] 2.27 [6.94-21.23], p = 0.001)) and lower likelihood of prior stroke (0.13 [0.33-0.86]), p = 0.024)) were independently associated with good outcomes. The ROC analysis demonstrated good performance of the CBV index in predicting good 90-day mRS (AUC 0.73, p = 0.003) with a threshold of 0.7 for optimal sensitivity (71% [52.0-85.8%]) and specificity (76% [54.9-90.6%]). The HIR also demonstrated adequate performance in predicting good 90-day mRS (AUC 0.77, p = 0.001) with a threshold of 0.3 for optimal sensitivity (64.5% [45.4-80.8%]) and specificity (76.0% [54.9-90.6%]).

CONCLUSION

A CBV index ≥ 0.7 may be independently associated with good clinical outcomes in our cohort of AIS caused by MCA-DMVOs that were successfully treated with MT. Furthermore, a HIR < 0.3 is also associated with good clinical outcomes. This is the first study of which we are aware to identify a CBV index threshold for MCA-DMVOs.

Diagnostic accuracy of large and medium vessel occlusions in acute stroke imaging by neurology residents and stroke fellows: A comparison of CT angiography alone and CT angiography with CT perfusion

INTRODUCTION

Neurology senior residents and stroke fellows are first to clinically assess and interpret imaging studies of patients presenting to the emergency department with acute stroke. The aim of this study was to compare the diagnostic accuracy of brain CT angiography (CTA) with and without CT perfusion (CTP) between neurology senior residents and stroke fellows.

METHODS

In this neuroimaging study, nine practitioners (four senior neurology residents (SNRs) and five stroke fellows (SFs)) clinically assessed and interpreted the imaging data of 50 cases (15 normal images, 21 large vessel occlusions (LVOs) and 14 medium vessel occlusions (MeVOs) in two sessions, 1 week apart in comparison to final diagnosis of experienced neuroradiologist and experienced stroke neurologist consensus. Interrater agreement of CTA alone and CTA with CTP was quantified using kappa statistics, sensitivity, specificity and overall accuracy.

RESULTS

Overall, arterial occlusions were correctly identified in 221/315 (70.1%) with CTA alone and in 266/315 (84.4%) with CTA and CTP (p < 0.001). The sensitivity of overall arterial occlusions detection with CTA alone was 94.2% (95% CI: 90.8%-96.6%) while with addition of CTP was 98% (95% CI: 95.6%-99.3%), The specificity of CTA alone was 74.7% (95% CI: 67.2%-81.3%) which increased with CTP to 84.4% (95% CI: 77.7%-89.8%). The likelihood of correct identification with CTA alone was 156/189 (82.54%) for LVOs and 65/126 (51.59%) for MeVOs. This increased to 169/189 (89.42%; p = 0.054) for LVOs and 97/126 (76.98%; p < 0.001) for MeVOs when the CTA images with CTP were viewed. There was good overall interrater agreement between readers when using CTA alone (k 0.71, 95% CI, 0.62-0.80) and almost perfect (k 0.85, 95% CI, 0.76-0.94) when CTP was added to the image for interpretation. CTA and CTP had a significantly lower median interquartile range (IQR) interpretation time than CTA alone (114 [IQR, 103-120] s vs 156 [IQR, 133-160] s, p < 0.001).

DISCUSSION

In cerebral arterial occlusions, the rate of LVO and MeVOs detections increases when adding CTP to CTA. The accuracy and time for diagnosing arterial occlusion can be significantly improved if CTP is added to CTA. As MeVOs are commonly missed by front-line neurology senior residents or stroke fellows, cases with significant deficits and no apparent arterial occlusions need to be reviewed with neuroradiological expertise.

Trends and predictors of decompressive craniectomy in acute ischemic stroke, 2011-2020

INTRODUCTION

Rates of decompressive craniectomy (DC) in acute ischemic stroke (AIS) have been reported to decline over time, attributed to an increase in endovascular therapy (EVT) preventing the development of malignant cerebral edema. We sought to characterize trends in DC in AIS between 2011 and 2020.

MATERIAL AND METHODS

We performed a retrospective observational study of U.S. AIS hospitalizations using the National Inpatient Sample, 2011 to 2020. We calculated rates of DC per 10,000 AIS among all AIS hospitalizations, as well as AIS hospitalizations undergoing invasive mechanical ventilation (IMV). A logistic regression to determine predictors of DC was performed.

RESULTS

Of ∼4.4 million AIS hospitalizations, 0.5 % underwent DC; of ∼300,000 AIS with IMV, 5.8 % underwent DC. From 2011 to 2020, the rate of DC increased from 37.4 to 59.1 per 10,000 AIS (p < 0.001). The rate of DC in patients undergoing IMV remained stable at ∼550 per 10,000 (p = 0.088). The most important factors predicting DC were age (OR 4.88, 95 % CI 4.53-5.25), hospital stroke volume (OR 2.61, 95 % CI 2.17-3.14), hospital teaching status (OR 1.54, 95 % CI 1.36-1.75), and transfer status (OR 1.53, 95 % CI 1.41-1.66); EVT status did not predict DC.

CONCLUSIONS

The rate of DC in AIS has increased between 2011 and 2020. Our findings are contrary to prior reports of decreasing DC rates over time. Increasing EVT rates do not seem to be preventing the occurrence of DC. Future research should focus on the decision-making process for both clinicians and surrogates regarding DC with consideration of long-term outcomes.

Follow-up infarct volume on fluid attenuated inversion recovery (FLAIR) imaging in distal medium vessel occlusions: the role of cerebral blood volume index

BACKGROUND

Distal medium vessel occlusions (DMVOs) contribute substantially to the incidence of acute ischemic strokes (AIS) and pose distinct challenges in clinical management and prognosis. Neuroimaging techniques, such as Fluid Attenuation Inversion Recovery (FLAIR) imaging and cerebral blood volume (CBV) index derived from perfusion imaging, have significantly improved our ability to assess the impact of strokes and predict their outcomes. The primary objective of this study was to investigate relationship between follow-up infarct volume (FIV) as assessed by FLAIR imaging in patients with DMVOs.

METHODS

This prospectively collected, retrospective reviewed cohort study included patients from two comprehensive stroke centers within the Johns Hopkins Medical Enterprise, spanning August 2018-October 2022. The cohort consisted of adults with AIS attributable to DMVO. Detailed imaging analyses were conducted, encompassing non-contrast CT, CT angiography (CTA), CT perfusion (CTP), and FLAIR imaging. Univariable and multivariable linear regression models were employed to assess the association between different factors and FIV.

RESULTS

The study included 79 patients with DMVO stroke with a median age of 69 years (IQR, 62-77 years), and 57% (n = 45) were female. There was a negative correlation between the CBV index and FIV in a univariable linear regression analysis (Beta =  - 16; 95% CI,  - 23 to  - 8.3; p < 0.001) and a multivariable linear regression model (Beta =  - 9.1 per 0.1 change; 95% CI,  - 15 to  - 2.7; p = 0.006). Diabetes was independently associated with larger FIV (Beta = 46; 95% CI, 16 to 75; p = 0.003). Additionally, a higher baseline ASPECTS was associated with lower FIV (Beta =  - 30; 95% CI,  - 41 to  - 20; p < 0.001).

CONCLUSION

Our findings underscore the CBV index as an independent association with FIV in DMVOs, which highlights the critical role of collateral circulation in determining stroke outcomes in this patient population. In addition, our study confirms a negative association of ASPECTS with FLAIR FIV and identifies diabetes as independent factor associated with larger FIV. These insights pave the way for further large-scale, prospective studies to corroborate these findings, thereby refining the strategies for stroke prognostication and management.

Incidence and clinical outcomes of perforations during mechanical thrombectomy for medium vessel occlusion in acute ischemic stroke: A retrospective, multicenter, and multinational study

BACKGROUND

Mechanical thrombectomy (MT) has revolutionized the treatment of acute ischemic stroke (AIS) due to large vessel occlusion (LVO), but its efficacy and safety in medium vessel occlusion (MeVO) remain less explored. This multicenter, retrospective study aims to investigate the incidence and clinical outcomes of vessel perforations (confirmed by extravasation during an angiographic series) during MT for AIS caused by MeVO.

METHODS

Data were collected from 37 academic centers across North America, Asia, and Europe between September 2017 and July 2021. A total of 1373 AIS patients with MeVO underwent MT. Baseline characteristics, procedural details, and clinical outcomes were analyzed.

RESULTS

The incidence of vessel perforation was 4.8% (66/1373). Notably, our analysis indicates variations in perforation rates across different arterial segments: 8.9% in M3 segments, 4.3% in M2 segments, and 8.3% in A2 segments (p = 0.612). Patients with perforation had significantly worse outcomes, with lower rates of favorable angiographic outcomes (TICI 2c-3: 23% vs 58.9%, p < 0.001; TICI 2b-3: 56.5% vs 88.3%, p < 0.001). Functional outcomes were also worse in the perforation group (mRS 0-1 at 3 months: 22.7% vs 36.6%, p = 0.031; mRS 0-2 at 3 months: 28.8% vs 53.9%, p < 0.001). Mortality was higher in the perforation group (30.3% vs 16.8%, p = 0.008).

CONCLUSION

This study reveals that while the occurrence of vessel perforation in MT for AIS due to MeVO is relatively rare, it is associated with poor functional outcomes and higher mortality. The findings highlight the need for increased caution and specialized training in performing MT for MeVO. Further prospective research is required for risk mitigation strategies.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Mechanical thrombectomy with Embolus Retriever with Interlinked Cages device for medium vessel occlusions: First pass results and safety profile

BACKGROUND

Reperfusion of medium vessel occlusions is correlated with good outcomes. However, optimal techniques and medical devices are still unclear. In this study, we sought to evaluate the safety and efficacy of mechanical thrombectomy with Embolus Retriever with Interlinked Cages (ERIC™) retrieval device in patients with acute ischemic stroke due to distal medium vessel occlusions.

METHODS

A retrospective review of the prospectively collected mechanical thrombectomy database revealed 50 patients who had fulfilled the inclusion criteria. The data collected includes clinical patient characteristics, procedural measures, timestamps at each stage, and patient outcomes. Intravenous thrombolytics application, pre- and post-intervention imaging findings, device-related adverse events and any type of intracranial hemorrhage were recorded.

RESULTS

There were 25 men (50%) and 25 women (50%) with a median of 67 years (interquartile range (IQR) 41-84). Median presenting NIHSS was 14 (IQR, 3-23). First pass rates were: eTICI3 in 16 cases (32%), eTICI-2c in eight cases (16%), eTICI-2B67 in nine cases (10%), eTICI2B50 in three cases (6%) and mTICI 0-2A in 18 cases (36%). Final recanalization rate of mTICI 2b-3 was 90% and 2c-3 was 70%.

CONCLUSION

In conclusion, the ERIC thrombectomy device offers a high rate of first-pass success along with a favorable safety profile. Larger series and multi-center studies are needed for further investigation.

Mechanical thrombectomy in medium vessel occlusions using the novel aspiration Q catheters: an international multicenter experience

BACKGROUND

Medium vessel occlusions (MeVOs) comprise a large proportion of all stroke events. We performed a multicenter study of MIVI Q catheters, a novel design that optimizes suction forces without an increase in lumen diameter, for the treatment of MeVOs, aiming to evaluate its efficacy and safety.

METHODS

Databases of two US and two UK centers were retrospectively reviewed for MeVO patients (M2-M3, anterior cerebral artery (ACA), or posterior cerebral artery (PCA)) treated with Q catheters. Outcomes were assessed as successful recanalization (modified Thrombolysis in Cerebral Infarction (mTICI) score ≥2b), first pass effect (FPE), and modified FPE (mFPE) as single pass achieving mTICI ≥2c and mTICI≥2b, respectively, and 90 day modified Rankin Scale (mRS) score.

RESULTS

69 patients were included (median age 71 years, IQR 56-82.5; 52.2% men). Median National Institutes of Health Stroke Scale (NIHSS) score at admission was 14, and Alberta Stroke Program Early CT Score (ASPECTS) was 9. Primary (without large vessel occlusion (LVO)) and secondary (with LVO) MeVOs represented 47.8% and 52.2% of cases, respectively. Q catheters used were Q3 (47.8%), Q4 (33.3%), Q5 (10.1%), and Q6 (8.7%). mTICI≥2b was achieved in 92.8% of patients, with FPE in 47.8%, and mFPE in 68.1%. Two (2.9%) intraprocedural complications (symptomatic intracranial hemorrhage) occurred. 50% (27/54) achieved an mRS score of ≤2 at the 90 day follow-up. The median NIHSS at admission was significantly higher in secondary than in primary MeVOs (19.5 vs 12, P=0.009). The rate of mRS ≤2 at 90 days was significantly higher in primary than in secondary MeVOs (77.3% vs 31.3%, P=0.002).

CONCLUSIONS

Treatment of MeVO patients with Q catheters resulted in optimal angiographic and clinical outcomes. Although angiographic results were similar between primary and secondary MeVOs, the former had less severe presenting NIHSS and better outcomes at 90 days than the latter.

Comparison of balloon guide catheter versus non-balloon guide catheter for mechanical thrombectomy in patients with distal medium vessel occlusion

BACKGROUND

Several studies have established the safety and efficacy of balloon guide catheters (BGCs) for large vessel occlusions. However, the utility of BGCs remains largely unexplored for distal medium vessel occlusions (DMVOs). In this study, we aim to compare the outcomes of BGC vs. Non-BGC in patients undergoing mechanical thrombectomy (MT) for DMVO.

METHOD

This retrospective study from the Stroke Thrombectomy and Aneurysm Registry (STAR) encompassed adult patients with acute anterior cerebral artery, posterior cerebral artery, and middle cerebral artery-M2-3-4 occlusions. Procedure times, safety, recanalization, and neurological outcomes were compared between the two groups, with subgroup analysis based on first-line thrombectomy techniques.

RESULTS

A total of 1508 patients were included, with 231 patients (15.3%) in the BGC group and 1277 patients (84.7%) in the non-BGC group. The BGC group had a lower modified Thrombolysis in Cerebral Infarction (mTICI) score ≥2C (43.2% vs 52.7%, P=0.01), longer time from puncture to intracranial access (15 vs 8 min, P<0.01), and from puncture to final recanalization (97 vs 34 min, P<0.01). In the Solumbra subgroup, the first pass effect (FPE) rate was lower in the BGC group (17.4% vs 30.7%, P=0.03). Regarding clinical outcomes, the BGC group had a lower rate of distal embolization (8.8% vs 14.9%, P=0.03).

CONCLUSION

Our study found that use of BGC in patients with DMVO was associated with lower mTICI scores, decreased FPE rates, reduced distal embolization, and longer procedure times.

Mechanical Thrombectomy for Pediatric Arterial Ischemic Stroke from Acute M2 Occlusion

Pediatric large-vessel occlusion has a poor natural history. Recent retrospective studies have demonstrated the potential benefits, feasibility, and safety profile of mechanical thrombectomy in children. However, the role of thrombectomy in pediatric M2 occlusions remains uncertain. In this clinical report, we present a multicenter series of 6 pediatric patients with acute M2 occlusion (female = 1, male = 5; age range, 0.9-16.0 years, mean = 9.2). All 6 patients having undergone thrombectomy had excellent clinical outcomes (pediatric mRS = 0-1) at 3 months and final available follow-up (median, 12 months; range, 3-72 months). Factors relevant to treatment decision-making in pediatric M2 occlusions are discussed, including the important role of multidisciplinary team discussions during acute management.

EnDovascular Therapy Plus Best Medical Treatment (BMT) Versus BMT Alone for MedIum distal VeSsel Occlusion sTroke (DISTAL): An international, multicentre, randomized-controlled, two-arm, assessor-blinded trial

RATIONALE

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

AIM

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

SAMPLE SIZE

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

METHODS AND DESIGN

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

OUTCOMES

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

DISCUSSION

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

Thrombectomy vs Medical Management for Posterior Cerebral Artery Stroke: Systematic Review, Meta-Analysis, and Real-World Data

BACKGROUND AND OBJECTIVES

There is a paucity of high-level evidence for endovascular thrombectomy (EVT) in posterior cerebral artery (PCA) strokes.

METHODS

The MEDLINE, Embase, and Web of Science databases were queried for well-conducted cohort studies comparing EVT vs medical management (MM) for PCA strokes. Outcomes of interest included 90-day functional outcomes, symptomatic intracranial hemorrhage (sICH), and death. The level of evidence was determined per the Oxford Centre for Evidence-Based Medicine criteria. We also conducted a propensity score matched (PSM) analysis of the 2016-2020 National Inpatient Sample (NIS) to provide support for our findings with real-world data.

RESULTS

A total of 2,095 patients (685 EVT and 1,410 MM) were identified across 5 well-conducted cohort studies. EVT was significantly associated with higher odds of no disability at 90 days (odds ratio [OR] 1.25, 95% CI 1.04-1.50, p = 0.015) but not functional independence (OR 0.87, 95% CI 0.72-1.07, p = 0.18). EVT was also associated with higher odds of sICH (OR 2.48, 95% CI 1.55-3.97, p < 0.001) and numerically higher odds of death (OR 1.32, 95% CI 0.73-2.38; p = 0.35). PSM analysis of 95,585 PCA stroke patients in the NIS showed that EVT (n = 1,540) was associated with lower rates of good discharge outcomes (24.4% vs 30.7%, p = 0.037), higher rates of in-hospital mortality (8.8% vs 4.9%, p = 0.021), higher rates of ICH (18.2% and 11.7%, p = 0.008), and higher rates of subarachnoid hemorrhage (3.9% vs 0.6%, p < 0.001). Among patients with moderate to severe strokes (NIH Stroke Scale 5 or greater), EVT was associated with significantly higher rates of good outcomes (21.7% vs 13.8%, p = 0.023) with similar rates of mortality (7.6% vs 6.6%, p = 0.67) and ICH (17.8% vs, 13.1%, p = 0.18).

DISCUSSION

Our meta-analysis revealed that while EVT may be effective in alleviating disabling deficits due to PCA strokes, it is not associated with different odds of functional independence and may be associated with higher odds of sICH. These findings were corroborated by our large propensity score matched analysis of real-world data in the United States. Thus, the decision to pursue PCA thrombectomies should be carefully individualized for each patient. Future randomized trials are needed to further explore the efficacy and safety of EVT for the treatment of PCA strokes.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that in patients with acute PCA ischemic stroke, treatment with EVT compared with MM alone was associated with higher odds of no disabling deficit at 90 days and higher odds of sICH.

Tenecteplase Versus Alteplase in Medium Vessel Occlusion Ischemic Stroke: A Secondary Analysis of the Alteplase Compared to Tenecteplase Randomized Trial

BACKGROUND AND PURPOSE

The safety and efficacy of tenecteplase in patients with ischemic stroke due to medium vessel occlusion (MeVO) are not well studied. We aimed to compare tenecteplase with alteplase in stroke due to MeVO.

METHODS

Patients with baseline M2-middle cerebral artery (MCA), M3/M4-MCA, P2/P3/P4-posterior cerebral artery (PCA), A2/A3/A4-anterior cerebral artery (ACA) occlusions from the Alteplase Compared to Tenecteplase (AcT) trial were included. Primary outcome was the proportion of 90-day modified Rankin Scale (mRS) 0-1. Secondary outcomes were 90-day mRS 0-2, ordinal mRS, mortality, quality of life measures (EuroQol 5-Dimension 5-Level, EuroQol visual analog scale), and symptomatic intracerebral hemorrhage (sICH). Initial and final successful reperfusion were reported in patients undergoing endovascular thrombectomy (EVT).

RESULTS

Among 1,558 patients with available baseline computed tomography angiography; 455 (29.2%) had MeVO of which 27.5% (125/455) were proximal M2; 16.3% (74/455) were distal M2; 35.2% (160/455) were M3/M4; 7.5% (34/455) were A2/A3/A4; and 13.6% (62/455) were P2/P3/P4 occlusions. EVT was performed in 87/455 (19.1%) patients. mRS 0-1 at 90 days was achieved in 37.9% in the tenecteplase versus 34.7% in the alteplase group (adjusted risk ratio [aRR] 1.07; 95% confidence interval [CI] 0.91-1.25). Rates of 90-day mRS 0-2, sICH, and mortality were similar in both groups. No statistical difference was noted in initial successful reperfusion rates (13.0% vs. 7.5%) among the 87 patients who underwent endovascular thrombectomy. However, final successful reperfusion was higher in the tenecteplase group (71.7% vs. 60.0%, aRR 1.29, 95% CI 1.04-1.61).

CONCLUSION

Intravenous tenecteplase had comparable safety, functional outcomes and quality of life compared to intravenous alteplase among patients with MeVO. Among those treated with EVT, tenecteplase was associated with higher successful reperfusion rates than alteplase.

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.

Endovascular Thrombectomy Versus Intravenous Thrombolysis of Posterior Cerebral Artery Occlusion Stroke

BACKGROUND AND PURPOSE

Posterior cerebral artery occlusion (PCAo) can cause long-term disability, yet randomized controlled trials to guide optimal reperfusion strategy are lacking. We compared the outcomes of PCAo patients treated with endovascular thrombectomy (EVT) with or without intravenous thrombolysis (IVT) to patients treated with IVT alone.

METHODS

From the multicenter retrospective Posterior cerebraL ArTery Occlusion (PLATO) registry, we included patients with isolated PCAo treated with reperfusion therapy within 24 hours of onset between January 2015 and August 2022. The primary outcome was the distribution of the modified Rankin Scale (mRS) at 3 months. Other outcomes comprised 3-month excellent (mRS 0-1) and independent outcome (mRS 0-2), early neurological improvement (ENI), mortality, and symptomatic intracranial hemorrhage (sICH). The treatments were compared using inverse probability weighted regression adjustment.

RESULTS

Among 724 patients, 400 received EVT+/-IVT and 324 IVT alone (median age 74 years, 57.7% men). The median National Institutes of Health Stroke Scale score on admission was 7, and the occluded segment was P1 (43.9%), P2 (48.3%), P3-P4 (6.1%), bilateral (1.0%), or fetal posterior cerebral artery (0.7%). Compared to IVT alone, EVT+/-IVT was not associated with improved functional outcome (adjusted common odds ratio [OR] 1.07, 95% confidence interval [CI] 0.79-1.43). EVT increased the odds for ENI (adjusted OR [aOR] 1.49, 95% CI 1.05-2.12), sICH (aOR 2.87, 95% CI 1.23-6.72), and mortality (aOR 1.77, 95% CI 1.07-2.95).

CONCLUSION

Despite higher odds for early improvement, EVT+/-IVT did not affect functional outcome compared to IVT alone after PCAo. This may be driven by the increased risk of sICH and mortality after EVT.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Design, Modeling, and Experimental Validation of an Active Microcatheter Driven by Shape Memory Effects

Microcatheters capable of active guidance have been proven to be effective and efficient solutions to interventional surgeries for cardiovascular and cerebrovascular diseases. Herein, a novel microcatheter made of two biocompatible materials, shape memory alloy (SMA) and polyethylene (PE), is proposed. It consists of a reconfigurable distal actuator and a separate polyethylene catheter. The distal actuator is created via embedding U-shape SMA wires into the PE base, and its reconfigurability is mainly dominated by the shape memory effect (SME) of SMA wires, as well as the effect of thermal mismatch between the SMA and PE base. A mathematical model was established to predict the distal actuator's deformation, and the analytical solutions show great agreement with the finite element results. Structural optimization of such microcatheters was carried out using the verified analytical model, followed by fabrication of some typical prototypes. Experimental testing of their mechanical behaviors demonstrates the feasibility of the structural designs, and the reliability and accuracy of the mathematical model. The active microcatheter, together with the prediction model, will lay a solid foundation for rapid development and optimization of active navigation strategies for vascular interventions.

Technical and clinical outcomes of thrombectomy in patients with acute medium vessel occlusion and large vessel occlusion; sub-analyses of Japan Trevo registry

BACKGROUND

Little is known about endovascular therapy (EVT) for patients with medium vessel occlusion (MeVO) and more work is needed to establish its efficacy and to understand hemorrhagic complications.

METHODS

We analyzed the Japan Trevo Registry, which enrolled patients with acute stroke who underwent EVT using Trevo Retriever alone or in combination with an aspiration catheter. The primary outcome was effective reperfusion, and the secondary outcome was modified Rankin scale 0-2 at 90 days. Safety outcomes, including intracranial hemorrhage (ICH), were evaluated using a subgroup analyses focused on any ICH.

RESULTS

Among 1041 registered patients, 1025 patients were analyzed. 253 patients had MeVOs, and the majority (89.3%) had middle cerebral artery segment 2 (M2). The median National Institutes of Health Stroke Scale scores at admission were 15 and 19 for the MeVO and LVO groups (p < 0.0001). The primary outcome was 88.9% in MeVO vs. 91.8% in LVO group: adjusted odds ratio (aOR) [95% confidence interval (CI)] 0.60 [0.35-1.03], p = 0.07, and the secondary outcome was 43.2% vs. 42.2%, and the aOR [95%CI] was 0.70 [0.48-1.002], p = 0.051. However, the incidence of any ICH was more prominent in MeVO than in LVO group (35.7% vs. 28.8%, aOR [95%CI] 1.54 [1.10-2.15], p = 0.01). In subgroup analyses, the incidences of any ICH in MeVO group were generally higher than those in LVO group.

CONCLUSIONS

The effective reperfusion rate did not differ significantly between MeVO and LVO groups. Future development of devices and treatments for MeVO with fewer hemorrhagic complications is desirable.

Endovascular treatment of distal medium vessel occlusions using microcatheter aspiration thrombectomy

BACKGROUND AND PURPOSE

Recent studies suggest that endovascular treatment (EVT) in distal medium vessel occlusion (DMVO) stroke is beneficial even beyond middle cerebral artery (MCA) - M2 segment. However, data about aspiration thrombectomy of DMVOs is scarce since common state-of-the-art aspiration catheters are usually too large for small distal intracranial arteries. We report our initial experiences using the microcatheter aspiration thrombectomy (MAT) technique as frontline therapy for acute DMVOs in the MCA territory.

METHODS

We retrospectively analyzed all acute ischemic stroke (AIS) patients that underwent MAT of a primary or secondary DMVO in the M3 or M4 segment between January 2019 and October 2021. Recanalization rates, procedural safety and outcome data were recorded.

RESULTS

MAT of acute M3 and M4 occlusions was performed in 19 patients with AIS. Six had isolated DMVO strokes, 13 had secondary DMVOs during EVT of a proximal large vessel occlusion. Successful revascularization to DMVO TICI ≥ 2b was achieved in 58% (11/19) with a single pass in all of them. The median National Institutes of Health Strokes Scale (NIHSS) score at admission and discharge was 12 and 3, respectively. 68% (13/19) of the patients had a good clinical outcome at discharge (modified Rankin Scale 0-2). No symptomatic complications related to MAT occurred.

CONCLUSIONS

MAT of DMVOs in the MCA territory is technically feasible and effective. Compared to stent retriever-based thrombectomy in DMVOs the hemorrhagic complication rate appears notably lower. Further studies are needed to validate the benefit of mechanical thrombectomy in the distal intracranial vasculature.

Pretreatment parameters associated with hemorrhagic transformation among successfully recanalized medium vessel occlusions

Although pretreatment radiographic biomarkers are well established for hemorrhagic transformation (HT) following successful mechanical thrombectomy (MT) in large vessel occlusion (LVO) strokes, they are yet to be explored for medium vessel occlusion (MeVO) acute ischemic strokes. We aim to investigate pretreatment imaging biomarkers representative of collateral status, namely the hypoperfusion intensity ratio (HIR) and cerebral blood volume (CBV) index, and their association with HT in successfully recanalized MeVOs. A prospectively collected registry of acute ischemic stroke patients with MeVOs successfully recanalized with MT between 2019 and 2023 was retrospectively reviewed. A multivariate logistic regression for HT of any subtype was derived by combining significant univariate predictors into a forward stepwise regression with minimization of Akaike information criterion. Of 60 MeVO patients successfully recanalized with MT, HT occurred in 28.3% of patients. Independent factors for HT included: diabetes mellitus history (p = 0.0005), CBV index (p = 0.0071), and proximal versus distal occlusion location (p = 0.0062). A multivariate model with these factors had strong diagnostic performance for predicting HT (area under curve [AUC] 0.93, p < 0.001). Lower CBV indexes, distal occlusion location, and diabetes history are significantly associated with HT in MeVOs successfully recanalized with MT. Of note, HIR was not found to be significantly associated with HT.