Impact of complete recanalization on clinical recovery in cardioembolic stroke patients with M2 occlusion

Endovascular therapy for acute ischemic stroke with distal medium vessel occlusion: a systematic review and meta-analysis

AIMS

Endovascular therapy (EVT) for distal medium vessel occlusions (DMVOs) is a potential frontier of acute ischemic stroke (AIS) treatment, but its efficacy against best medical therapy (BMT) remains unknown. We performed a systematic review and meta-analysis evaluating the efficacy and safety of EVT versus BMT in primary DMVO.

METHODS

We systematically searched PubMed, Cochrane Library and Embase, from inception to August 14, 2022, for studies comparing EVT with BMT in DMVO-AIS. We adopted the Distal Thrombectomy Summit Group's definition of DMVO. Efficacy outcomes were functional independence (90-day modified Rankin Scale (mRS) 0-2) and excellent functional outcomes (90-day mRS 0-1). Safety outcomes were symptomatic intracranial hemorrhage (sICH) and 90-day mortality.

RESULTS

Fourteen observational and two randomized-controlled studies were included, with 1202 patients receiving EVT and 1267 receiving BMT. After trim-and-fill correction, EVT achieved significantly better odds of functional independence than BMT (adjusted OR 1.61, 95% CI 1.06 to 2.43). There were no significant differences in overall excellent functional outcomes (OR 1.23, 95% CI 0.88 to 1.71), sICH (OR 1.44, 95% CI 0.78 to 2.66), and mortality (OR 1.03, 95% CI 0.73 to 1.45). Stratified by EVT method, mechanical thrombectomy±intra-arterial thrombolysis achieved more excellent functional outcomes than BMT (OR 1.59, 95% CI 1.13 to 2.23). In mild strokes (National Institutes of Health Stroke Scale score <6), EVT caused significantly more sICH (OR 6.30, 95% CI 1.55 to 25.64).

CONCLUSIONS

EVT shows promising efficacy benefit over BMT for primary DMVO-AIS. Further randomized controlled trials are necessary to evaluate the efficacy and safety of EVT in DMVO-AIS.

Thrombectomy in M2 occlusion compared to M1 occlusion: treatment effects of Thrombolysis In Cerebral Infarction (TICI) 2b and TICI 3 recanalization on functional outcome

BACKGROUND

Emerging data suggest that mechanical thrombectomy (MT) might also be safe and efficient for medium and distal occlusions. This study aims to compare average treatment effects on functional outcome of different degrees of recanalization after MT in patients with M2 occlusion and M1 occlusion.

METHODS

All patients enrolled in the German Stroke Registry (GSR) between June 2015 and December 2021 were analyzed. Inclusion criteria were stroke with primary M1 occlusion or M2 occlusion, and availability of relevant clinical data. 4259 patients were included, thereof 1353 with M2 occlusion and 2906 with M1 occlusion. Treatment effects were analyzed using double-robust inverse-probability-weighted regression-adjustment (IPWRA) estimators to control for confounding covariates. Binarized endpoint metrics were defined as good outcome with modified Rankin Scale (mRS) ≤2 at 90 days, and linearized endpoint metrics were defined as mRS shift pre-stroke to 90 days. Effects were evaluated for near complete recanalization (Thrombolysis In Cerebral Infarction scale (TICI) 2b) and complete recanalization (TICI 3).

RESULTS

Treatment effect estimation for TICI ≥2b versus TICI <2b in M2 occlusions showed an increase in the probability of a good outcome from 27% to 47% with a number-needed-to-treat (NNT) of 5. For M1 occlusions the probability of a good outcome increased from 16% to 38% with NNT 4.5. TICI 3 versus TICI 2b increased the probability of a good outcome by 7 percentage points in M1 occlusions; for M2 occlusions the beneficial effect was not significant.

CONCLUSIONS

Results suggest that successful recanalization with TICI ≥2b versus TICI <2b after MT in M2 occlusions provides significant patient benefit with treatment effects comparable to M1 occlusions. The probability of functional independence increased by 20 percentage points (NNT 5) and stroke-related mRS increase was reduced by 0.9 mRS points. In contrast to M1 occlusions, complete recanalization TICI 3 versus TICI 2b had lower additional beneficial effect.

Impact of insufficient recovery of cerebral blood flow due to partial reperfusion on the pathophysiology of ischemic stroke in mice

Recent advances in endovascular treatment (EVT) dramatically changed the outcome of ischemic stroke, but partial reperfusion does not improve the outcome as well as no reperfusion. Although partial reperfusion is estimated to be more potential for therapeutic intervention than permanent occlusion due to some blood supply, their pathophysiological difference is still unknown. To answer the question, we analyzed the difference in mice, which were exposed to distal middle cerebral artery occlusion with 14-min common carotid artery (CCA) occlusion (partial reperfusion) or permanent CCA occlusion (no reperfusion). Although the final infarct volume was same between permanent and partial reperfusion, Fluoro-jade C staining showed that neurodegeneration was inhibited both in the severe and moderate ischemic region 3 h after partial reperfusion. Also, partial reperfusion increased the number of TUNEL-positive cells only in the severe ischemic region. IgG extravasation was suppressed at 24 h only in the moderate ischemic region in partial reperfusion. Injected FITC-dextran was observed in the brain parenchyma with BBB leakage at 24 h in partial reperfusion, but not in permanent occlusion. The expression of il1β and il6 mRNA was inhibited in the severe ischemic region. Thus, partial reperfusion showed region-dependent favorable pathophysiology, such as delayed neurodegeneration, suppressed BBB destruction and inflammation, and potential for drug delivery, when compared to permanent occlusion. Further studies on the molecular differences and effectiveness of drugs will shed light on the development of novel treatments for partial reperfusion in ischemic stroke.

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.

Which is the most effective rescue treatment after the failure of mechanical thrombectomy for acute basilar artery occlusion?

Objective

The aim of this study was to evaluate the effectiveness and safety of rescue therapy, a therapy in which rescue devices such as balloon angioplasty, Apollo stent, Wingspan stent, Solitaire stent, or other self-expanding stents are used after the failure of mechanical thrombectomy (MT) and to determine the most effective rescue measure for acute basilar artery occlusion (BAO) after the failure of MT.

Methods

For this study, we recruited patients from the BASILAR registry. All participants were divided into three groups: the recanalized with rescue therapy group, the recanalized without rescue therapy group, and the non-recanalized group. Clinical outcomes at 90 days and 1 year were compared. The association of rescue measures with favorable outcomes (modified Rankin Scale [mRS] score of 0–3) in patients achieving successful recanalization via rescue therapy was estimated using multivariate logistic regression analyses.

Results

Among the participants, recanalization failure was found in 112 patients and successful recanalization in 473 patients, with 218 patients receiving rescue therapy and 255 patients without rescue therapy. Of these, 111 (43.5%) patients in the recanalized without rescue therapy group, 65 (29.8%) patients in the recanalized with rescue therapy group, and nine (8.0%) patients in the non-recanalized group achieved favorable outcomes at 90 days. Both the recanalization with rescue therapy and the recanalization without rescue therapy groups were associated with favorable outcomes at 90 days and 1 year compared with the non-recanalized group. Moreover, in patients receiving rescue therapy, Wingspan stents, Apollo stents, and balloon angioplasty were associated with higher rates of favorable outcomes at 90 days and 1 year than Solitaire stents.

Conclusion

Whether rescue therapy is administered or not, recanalization leads to favorable outcomes in patients with acute BAO. For acute BAO after MT failure, balloon angioplasty, Wingspan stenting, and Apollo stenting could be considered effective and safe rescue options but not Solitaire stenting.

Fluid-Attenuated Inversion Recovery May Serve As a Tissue Clock in Patients Treated With Endovascular Thrombectomy

[Figure: see text].

The Natural History and Reperfusion Therapy Outcomes of Acute Ischemic Stroke due to Isolated M2 Occlusions

Objective

Currently, the standard treatment modality for patients with acute ischemic stroke (AIS) presenting with isolated M2 occlusions is not specific. We therefore assessed the difference in treatment outcomes for patients with isolated M2 occlusions.

Methods

We retrospectively analyzed consecutive patients with AIS presenting with isolated M2 occlusions from October 1, 2018, to June 30, 2020. Patients were divided into 3 groups based on the treatments they received: no reperfusion therapy (NRT), intravenous thrombolysis treatment (IVT), and endovascular intervention (EVT), which comprised IVT in conjunction with EVT or EVT alone. The primary outcomes were improvements in modified Rankin Scale (mRS) scores at 90 days and National Institutes of Health Stroke Scale (NIHSS) scores at 24 hours after treatment compared with the baseline. The secondary efficacy outcome comprised a good outcome rate defined as a 90 − day mRS score ≤ 2, final infarct volume (FIV), 90-day mortality rate, and successful recanalization rate, which was defined as a modified thrombolysis in cerebral infarction score ≥ 2b. Safety outcomes included symptomatic intracerebral hemorrhage and procedure-related complications.

Results

Seventy patients were enrolled and divided into 3 groups: the NRT group (n = 25), IVT group (n = 27), and EVT group (n = 18). Twenty-four-hour posttreatment NIHSS scores were substantially decreased by EVT compared with NRT (adjusted β -4.01, 95% confidence interval [CI] -6.60 to -1.43; P = 0.003) or IVT (adjusted β, -3.61 [95% CI, -6.45 to -0.77]; P = 0.013). Compared with the outcomes observed after NRT, patients who received EVT were more likely to achieve lower 90-day mRS scores (adjusted β, -1.42 [95% CI, -2.66 to -0.63]; P = 0.007), higher good outcome rates (adjusted odds ratio, 8.73 [95% CI, 1.43-53.24]; P = 0.019), and smaller FIVs (adjusted β, -29.66 [95% CI, -59.73 to 0.42]; P = 0.048). The recanalization rate of EVT was high (88.89%), and procedure-related complications were rare (5.56%).

Conclusions

For acute, isolated M2 occlusions, EVT could dramatically and rapidly improve neurological deficits with high safety and effectiveness. These changes were observed at 24 hours after treatment and were maintained over the long term.

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.