Meta-Analysis of Endovascular Treatment for Acute M2 Occlusion

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Endovascular treatment achieves better outcomes than best medical management in patients with M2 occlusion and high stroke severity: a meta-analysis

BACKGROUND

The lack of randomized evidence makes it difficult to establish reliable treatment recommendations for patients with M2 occlusion. This study aims to compare the efficacy and safety of endovascular treatment (EVT) with best medical management (BMM) in patients with M2 occlusion, and to investigate whether the optimal treatment varies according to stroke severity.

METHODS

Comprehensive literature retrieval was conducted to identify studies that directly compared the outcomes of EVT and BMM. According to stroke severity, the study population were classified into those with moderate-severe stroke and those with mild stroke. National Institute of Health Stroke Scale (NIHSS) scores ≥ 6 was defined as moderate-severe stroke, and NIHSS scores 0-5 as mild stroke. Random-effects meta-analyses were performed to measure the symptomatic intracranial hemorrhage (sICH) within 72 h, and the modified Rankin Scale (mRS) scores 0-2 and the mortality at 90 days.

RESULTS

Totally, 20 studies were identified, including 4358 patients. In the moderate-severe stroke population, the EVT had 82% higher odds for mRS scores 0-2 (OR 1.82, 95% CI 1.34-2.49) and a 43% lower odds for mortality (OR 0.57, 95% CI 0.39-0.82) compared with the BMM. However, no difference was found in the sICH rate (OR 0.88, 95% CI 0.44-1.77). In the mild stroke population, no differences were observed in the mRS scores 0-2 (OR 0.81, 95% CI 0.59-1.10) or mortality (OR 1.23, 95% CI 0.72-2.10) between EVT and BMM, whereas EVT was associated with higher sICH rate (OR 4.21, 95% CI 1.86-9.49).

CONCLUSION

EVT may be only beneficial for patients with M2 occlusion and high stroke severity, but not for those with NIHSS scores 0-5.

Intraarterial urokinase for thrombus migration after mechanical thrombectomy for large vessel ischemic stroke

BACKGROUND

Achieving rapid and complete reperfusion is the ultimate purpose for ischemic stroke with large vessel occlusion (LVO). Although mechanical thrombectomy (MT) had been a proverbially important procedure, medium vessel occlusion (MeVO) with thrombus migration can sporadically occur after MT. Moreover, the safe and effective approach for such had been unknown. We reported thrombolysis with intraarterial urokinase for MeVO with thrombus migration after MT.

METHODS

We included 122 patients who were treated by MT with LVO stroke at our institution between April 2019 and March 2021. Of 26 patients (21.3%) who developed MeVO with thrombus migration after MT, 11 (9.0%) underwent additional MT (MT group) and 15 (12.3%) received intraarterial urokinase (UK group). The procedure time; angiographically modified Treatment in Cerebral Ischemia Scale (mTICI); functional independence, which was defined as modified Rankin Scale 0-2, on day 30 or upon discharge; and symptomatic and asymptomatic intracerebral hemorrhage (ICH) were compared between the UK and MT groups.

RESULTS

The procedure time, mTICI, and asymptomatic ICH did not significantly differ between the groups. In the UK group, 8 of 15 (53.3%) patients obtained functional independence, and the functional independence rate was significantly higher in the UK group than in the MT group (p < 0.05). Symptomatic ICH did not occur in the UK group, and its incidence was significantly smaller than that in the MT group (p < 0.05).

CONCLUSION

The results of this study suggest that intraarterial urokinase for MeVO with thrombus migration after MT may safely improve angiographic reperfusion.

Multicenter investigation of technical and clinical outcomes after thrombectomy for Proximal Medium Vessel Occlusion (pMeVO) by frontline technique

BACKGROUND

Endovascular thrombectomy(EVT) is the standard of care for large vessel occlusion(LVO) stroke. Data on technical and clinical outcome in proximal medium vessel occlusions(pMeVOs) comparing frontline techniques remain limited.

METHODS

We report an international multicenter retrospective study of patients undergoing EVT for stroke at 32 centers between 2015-2021. Patients were divided into LVOs(ICA/M1/Vertebrobasilar) or pMeVOs(M2/A1/P1) and categorized by thrombectomy technique. Primary outcome was 90-day good functional outcome(mRS ≤ 2). Multivariate logistic regressions were used to evaluate the impact of technical variables on clinical outcomes. Propensity score matching was used to compare outcome in patients with pMeVO treated with aspiration versus stent-retriever.

RESULTS

In the cohort of 5977 LVO and 1287 pMeVO patients, pMeVO did not independently predict good-outcome(p  =  0.55). In pMeVO patients, successful recanalization irrespective of frontline technique(aOR = 3.2,p < 0.05), procedure time ≤ 1-h(aOR = 2.2,p < 0.05), and thrombectomy attempts ≤ 4(aOR =  2.8,p < 0.05) were independent predictors of good-outcomes.In a propensity-matched cohort of aspiration versus stent-retriever pMeVO patients, there was no difference in good-outcomes. The rates of hemorrhage were higher(9%vs.4%,p < 0.01) and procedure time longer(51-min vs. 33-min,p < 0.01) with stent-retriever, while the number of attempts was higher with aspiration(2.5vs.2,p < 0.01). Rates of hemorrhage and good-outcome showed an exponential relationship to procedural metrics, and were more dependent on time in the aspiration group compared to attempts in the stent-retriever group.

CONCLUSIONS

Clinical outcomes following EVT for pMeVO are comparable to those in LVOs. The golden hour or 3-pass rules in LVO thrombectomy still apply to pMeVO thrombectomy. Different techniques may exhibit different futility metrics; SR thrombectomy was more influenced by attempts whereas aspiration was more dependent on procedure time.

Middle Cerebral Artery M2 Thrombectomy: Safety and Technical Considerations in the German Stroke Registry (GSR)

There is ongoing debate concerning the safety and efficacy of various mechanical thrombectomy (MT) approaches for M2 occlusions. We compared these for MT in M2 versus M1 occlusions. Subgroup analyses of different technical approaches within the M2 MT cohort were also performed. Patients were included from the German Stroke Registry (GSR), a multicenter registry of consecutive MT patients. Primary outcomes were reperfusion success events. Secondary outcomes were early clinical improvement (improvement in NIHSS score > 4) and independent survival at 90 days (mRS 0−2). Out of 3804 patients, 2689 presented with M1 (71%) and 1115 with isolated M2 occlusions (29%). The mean age was 76 (CI 65−82) and 77 (CI 66−83) years, respectively. Except for baseline NIHSS (15 (CI 10−18) vs. 11 (CI 6−16), p < 0.001) and ASPECTS (9 (CI 7−10) vs. 9 (CI 8−10, p < 0.001), baseline demographics were balanced. Apart from a more frequent use of dedicated small vessel stent retrievers (svSR) in M2 (17.4% vs. 3.0; p < 0.001), intraprocedural aspects were balanced. There was no difference in ICH at 24 h (11%; p = 1.0), adverse events (14.4% vs. 18.1%; p = 0.63), clinical improvement (62.5% vs. 61.4 %; p = 0.57), mortality (26.9% vs. 22.9%; p = 0.23). In M2 MT, conventional stent retriever (cSR) achieved higher rates of mTICI3 (54.0% vs. 37.7−42.0%; p < 0.001), requiring more MT-maneuvers (7, CI 2−8) vs. 2 (CI 2−7)/(CI 2−2); p < 0.001) and without impact on efficacy and outcome. Real-life MT in M2 can be performed with equal safety and efficacy as in M1 occlusions. Different recanalization techniques including the use of svSR did not result in significant differences regarding safety, efficacy and outcome.

The Feasibility Mechanism of Nerve Interventional Thrombectomy for Occlusion of Cranial Artery M1 and M2 Segments

This study was aimed at exploring the feasibility and clinical efficacy of nerve interventional thrombectomy (NIT) to treat occlusion of cranial artery M1 and M2 segments. 80 patients were selected and rolled into a control group (intravenous thrombolysis) and an experimental group (NIT). Patients' vascular recanalization rates following therapy were compared, and the National Institutes of Health Stroke Scale (NIHSS) was used to measure neurological function. The improvement in hemodynamics and the occurrence of adverse responses were compared. The results showed that the experimental group's recanalization rate was up to 74.23%, which was significantly greater than the control group's (P < 0.05). One week after treatment, the neurological function scores in both groups decreased, and the score in the experimental group was only 15.23, which was much lower than that in the control group (P < 0.05). The peak systolic flow rates of the basilar artery, internal carotid artery, and common carotid artery in the experimental group were 132 cm/s, 147 cm/s, and 114 cm/s, respectively, which were lower greatly than those in the control group (P < 0.05). There was no significant difference in incidence of adverse reactions between the two groups (P > 0.05). In summary, NIT showed a significant therapeutic effect on cranial artery occlusion of M1 and M2 segments, can dredge the occluded blood vessels, and effectively improve the neurological deficits of patients, showing reliable feasibility.

A review of endovascular treatment for medium vessel occlusion stroke

Medium-vessel occlusions (MeVOs), that is, occlusions of the M2/3 middle cerebral artery, A2/3 anterior cerebral artery, and P2/3 posterior cerebral artery segments, account for 25%-40% of all acute ischemic stroke cases. Clinical outcomes of MeVO stroke with intravenous thrombolysis, which is the current standard of care, are moderate at best. With improving imaging technologies and a growing literature, MeVOs are increasingly recognized as a target for endovascular treatment (EVT). For the time being, there is limited but promising evidence for the safety and efficacy of MeVO EVT, and many neurointerventionists are already routinely offering EVT for MeVO stroke, despite the lack of clear guideline recommendations. In this article, we review the evidence on endovascular treatment for MeVO stroke and summarize the available literature on current imaging strategies, commonly used EVT selection criteria, EVT techniques, and outcome assessment for MeVO stroke.

Endovascular treatment versus intravenous thrombolysis alone in isolated M2 occlusion: a meta-analysis

BACKGROUND

Optimal reperfusion strategies for M2 occlusion are still uncertain, with previous studies questioning benefit of mechanical thrombectomy (MT) over intravenous thrombolysis alone (IVT). Here we systematically reviewed and meta-analyzed data from studies comparing IVT alone vs MT with/without previous IVT, to define risk/benefit profile of each paradigm.

METHODS

The study followed PRISMA guidelines. PubMed, EMBASE, and Cochrane Central were searched only for RCTs comparing MT with or without IVT vs IVT alone in adults with acute ischemic stroke and M2 occlusion. Primary endpoint was functional independence at 90 days (modified Rankin Scale<3); secondary endpoints were represented by symptomatic intracranial hemorrhage (sICH) and good recanalization (TICI>2a). Odds ratios for endpoints were pooled with meta-analysis and compared between reperfusion strategies.

RESULTS

Seven studies (n=779) were included, all of high quality. Rate of good functional outcome was similar for MT and IVT (62.4% vs 66.3%; OR=0.73; 95%CI: 0.38-1.41; p_{heterogeneity}=0.008) (Fig. 1).sICH was significantly more frequent in the MT group (8.5%) vs IVT group (3%) (OR 2.76, 95%CI 1.19-6.36, p_{heterogeneity}=0.14). Good recanalization (TICI>2a) rate was higher in MT group vs IVT alone group (81.2% vs 51.4%; OR 3.99; 95%CI: 1.98-8.94; p_{heterogeneity}=0.80).

CONCLUSIONS

IVT alone provides similar clinical benefit compared to MT with/without IVT in cases of M2 occlusion. MT quadruplicates rates of good recanalization, but triplicates risk of sICH. Further trials are needed to define if MT confers any advantage over IVT for M2 occlusion.

Solitary Sign of Third Nerve Palsy in a Conscious Patient With Epidural Hemorrhage

Epidural hematoma is a life-threatening complication of head injury, which often occurs as a result of blunt trauma to the skull. Unregulated hematoma expansion in any setting results in elevated intracranial pressure and may contribute to the compression of the oculomotor nerve among several other adversities culminating in various long-lasting complications in the future. In this case report, we present the findings of a rare, insightful case of a 47-year-old Southeast Asian male with no established prior medical history apart from being a victim of blunt trauma attributable to a fall four days before presenting to the emergency department with abrupt onset of diplopia and drooping of the left eyelid. The initial physical examination helped to establish a diagnosis of third nerve palsy. A non-contrast CT of the head was conducted, and its findings revealed the presence of a right temporal-parietal-occipital epidural hemorrhage, with no mass impact on the cerebral hemisphere. The patient later underwent a successful left temporoparietal craniotomy, during which 100-125 ml of blood was drained out. Post-surgery, a near-full reduction of ptosis was recorded at the end of the first week. This case report summarizes this ingenious depiction of a partial third nerve palsy presenting as the sole sign of the epidural hemorrhage in a cognizant patient.

Neuroanatomy of the middle cerebral artery: implications for thrombectomy

Our perspective on anatomy frequently depends on how this anatomy is utilized in clinical practice, and by which methods knowledge is acquired. The thrombectomy revolution, of which the middle cerebral artery (MCA) is the most common target, is an example of a clinical paradigm shift with a unique perspective on cerebrovascular anatomy. This article reviews important features of MCA anatomy in the context of thrombectomy. Recognizing that variation, frequently explained by evolutionary concepts, is the rule when it comes to branching pattern, vessel morphology, territory, or collateral potential is key to successful thrombectomy strategy.