Distal medium vessel occlusions in acute ischaemic stroke - Stent retriever versus direct aspiration: A systematic review and meta-analysis

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.

Mechanical thrombectomy for middle cerebral artery M2 occlusions

BACKGROUND

The safety and efficacy of mechanical thrombectomy (MT) for proximal large vessel occlusion after acute ischemic stroke (AIS) have been demonstrated. Clinical investigations of endovascular approaches for treating AIS due to M2 occlusions have been ongoing.

PURPOSE

To assess the outcomes of M2 occlusions according to treatment modality and anatomical division.

METHODS

A total of 113 consecutive M2 occlusions treated with endovascular treatment (EVT) at our tertiary stroke center between January 2019 and December 2022 were retrospectively analyzed. Patients were divided into three groups: mechanical thrombectomy (MT); intravenous thrombolysis plus MT (IVT + MT); and IVT alone. The primary outcomes were good prognosis (mRS = 0-2) and mortality (mRS = 6) on day 90. The secondary outcome was to determine the differences in outcomes between lesions in the superior and inferior branches of M2.

RESULTS

In total, 55 (48.7%) patients underwent MT. In 42 (37.2%) patients, bridging IVT was performed with MT, and IVT alone was applied in 16 (14.2%) patients. Neither the prognosis at 90 days nor the mortality rate significantly differed among the groups. The outcomes did not significantly differ between occlusions in the superior and inferior branches of M2.

CONCLUSION

MT was found to be safe and effective for treating M2 occlusions in this series.

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.

Procedural factors associated with successful recanalization in patients with acute ischemic stroke treated with endovascular thrombectomy-a nationwide register-based observational study

INTRODUCTION

Several studies have addressed technical aspects of endovascular thrombectomy (EVT), but it is not well known how procedural factors contribute to technical success in routine healthcare. The aim was to explore factors associated with technically successful EVT on nationwide scale.

METHODS

We did an observational register-based study assessing factors associated with technical success off anterior circulation EVT in Sweden. The main outcome was successful recanalization defined as modified treatment in cerebral ischemia score 2b-3. The association between baseline and treatment variables and successful recanalization were explored using Chi-square(d) test and univariable logistic regression. Multivariable logistic regression was used to define predictors of successful recanalization.

RESULTS

The study included 3211 patients treated during 2015 to 2020. Successful recanalization was achieved in 83.1% (2667) with a gradual improvement in technical outcome over the period. After adjustment for age and occlusion location, thet use of general anesthesia, balloon guide catheter (BGC) and an operator with an overall success rate of >85% were independent predictors of successful recanalization. An overall operator success rate of <80% or 80-85%, and an annual center volume lower than 50 were predicitors of recanalization failure.

CONCLUSION

This study illustrates factors associated with procedural success in endovascular thrombectomy on a nationwide scale including the use of general anesthesia, BGC, annual center volumes >50 cases per year and the overall success rate of the individual operator. It highlights the potential benefit of systematic performance measurements, benchmarking, and continuous training to bring all centers and operators to the highest level of performance.

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.

Safety and efficacy of endovascular thrombectomy for primary and secondary MeVO

BACKGROUND

Medium-vessel occlusions (MeVO) are emerging as a new target for endovascular treatment (EVT). Primary MeVO occur de novo, while secondary MeVO arise from large vessel occlusion (LVO) through clot migration or fragmentation - spontaneously, following intravenous thrombolysis or EVT. We aimed to evaluate efficacy and safety of EVT in primary and EVT-induced secondary MeVO.

METHODS

Retrospective single-center study on consecutive EVT-treated acute ischemic stroke, from 2019-to-2021. We considered: (1) exclusive-LVO, patients with LVO and - in case of residual distal occlusion - no rescue endovascular procedure; (2) primary MeVO: initial A2, A3, M2 non-dominant, M3, P2, P3 occlusions; (3) EVT-induced secondary MeVO, presenting LVO with subsequent (treated) EVT-induced MeVO. We compared (univariable/multivariable logistic regression) EVT efficacy (eTICI≥2b, 3-month modified Rankin Scale [mRS] 0-2) and safety (EVT-complications [vessel dissection, perforation, persistent-SAH], symptomatic ICH) in all MeVO versus exclusive-LVO, primary MeVO versus exclusive-LVO, EVT-induced secondary MeVO versus exclusive-LVO and EVT-induced secondary MeVO versus primary MeVO.

RESULTS

We included 335 patients: 221 (66.0 %) exclusive-LVO and 114 (34.0 %) MeVO (55 [48.2 %] primary, 59 [51.8 %] secondary). Compared to exclusive-LVO, primary MeVO had higher rates of EVT complications (aOR 3.77 [95%CI 1.58-9.00],p=0.003), lower rates of eTICI≥2b (aOR 0.32 [95%CI 0.12-0.88],p=0.027) and mRS 0-2 (aOR 0.28 [95%CI 0.13-0.63],p=0.002). EVT-induced secondary MeVO had no major differences in efficacy and safety outcomes compared to exclusive-LVO, but a better mRS 0-2 (aOR 8.00 [95%CI 2.12-30.17],p=0.002) compared to primary MeVO.

CONCLUSIONS

Primary and EVT-induced secondary MeVO showed different safety/efficacy EVT-related profiles. Dedicated randomized data are needed to identify the best acute reperfusion strategy in the two categories.

Contemporary Methods for Detection and Intervention of Distal Medium and Small Vessel Occlusions

The efficacy of using mechanical thrombectomy for proximal large vessel occlusions has been demonstrated in multiple large-scale trials and has further raised the question of its potential utility for distal medium and small vessel occlusions (DMSVOs). Their longer, more tortuous course and smaller corresponding vascular territories render a significant challenge for detection and intervention. The aim of this study is to provide a comprehensive overview of the current imaging and endovascular intervention options for DMSVOs and review the current works in the literature. Compared with traditional computed tomography angiography (CTA) and CT perfusion, recent advances such as multiphase CTA and maps derived from the time-to-maximum parameter coupled with artificial intelligence have demonstrated increased sensitivity for the detection of DMSVOs. Furthermore, newer generations of mini stent retrievers and thromboaspiration devices have allowed for the access and navigation of smaller and more fragile distal arteries. Preliminary studies have suggested that mechanical thrombectomy using this newer generation of devices is both safe and feasible in distal medium-sized vessels, such as M2. However, endovascular intervention utilizing such contemporary methods and devices must be balanced at the discretion of operator experience and favorable vascular anatomy. Further large-scale multicenter clinical trials are warranted to elucidate the indications for as well as to strengthen the safety and efficacy of this approach.