Clinical Outcomes of Endovascular Treatment within 24 Hours in Patients with Mild Ischemic Stroke and Perfusion Imaging Selection

Clinical effect of successful reperfusion in patients presenting with NIHSS < 6 and large vessel occlusion

PURPOSE

The purpose of this study was to evaluate the impact of reperfusion in patients with large vessel occlusion (LVO) of the anterior circulation and National Institutes of Health Stroke Scale (NIHSS)< 6.

METHODS

It was a retrospective cohort study. The reperfusion grade was determined using the modified thrombolysis in cerebral infarction (TICI) score. The modified Rankin Score (mRS) ≤1 were defined as excellent and (mRS) ≤2 as favorable outcome at 3-month. Meanwhile, the all-cause mortality, intracerebral hemorrhage, and complications were recorded. Multivariate logistic regression analyses were performed to evaluate outcomes.

RESULTS

Seventy-six patients (86.4%) achieved reperfusion (TICI2B/3). Excellent outcome was achieved in 62 (70.5%) and favorable outcome in 69 (78.4%). All-cause death occurred in 2 (2.3%). The rate of excellent outcome in patients with TICI0,1,2A was 41.7%, with TICI2B 69.2%, and with TICI3 78.0% (p < 0.05). In a multivariate logistic regression analysis related to excellent outcome, the OR(95% CI) was 5.68(1.35,23.95) for TICI3; the test for linear trend by entering categorical variables as continuous variables in the adjusted model (p for trend=0.02<0.05), defining TICI0,1,2A as reference. Subgroup analyses showed without intravenous thrombolysis (IVT) (OR, 14.29; 95% CI, 1.76-116.37) and with middle cerebral artery (MCA) occlusion (OR, 7.97; 95% CI,1.26-50.32), the excellent outcome further improved with TICI3. Findings were similar in favorable outcome.

CONCLUSIONS

Our results indicated that successful reperfusion was intensely connected with better functional outcomes for patients with LVO presenting with NIHSS<6 in the anterior circulation, especially MCA occlusion and pretreatment without IVT.

Three Dimensional-Arterial Spin Labeling Evaluation of Improved Cerebral Perfusion After Limb Remote Ischemic Preconditioning in a Rat Model of Focal Ischemic Stroke

Purpose

To investigate the application value of 3D arterial spin labeling (3D-ASL) for evaluating distal limb ischemic preconditioning to improve acute ischemic stroke (AIS) perfusion.

Materials and Methods

A total of 40 patients with AISs treated in our hospital from January 2020 to December 2020 were recruited, and 15 healthy individuals who were examined in our hospital during the same period were included as the control group; all of these participants were scored on the National Institutes of Health Stroke Scale (NIHSS) and examined by MRI. Sequences included conventional sequences, diffusion-weighted imaging (DWI), magnetic resonance angiography (MRA), and 3D-ASL, and cerebral infarct volume and cerebral blood flow (CBF) in the area of the infarct lesion were measured. After 3 months of treatment, patients with AIS were scored on the modified Rankin Scale (mRS) and divided into good prognosis and poor prognosis groups. In total, 55 adult male Sprague–Dawley rats were divided randomly into three groups: 20 in the middle cerebral artery occlusion (MCAO) group, 20 in the MCAO + limb remote ischemic preconditioning (LRP) group, and 15 in the sham group. In total, 48 h after the procedures, conventional MRI, DWI, and 3D-ASL sequence data were collected, and 2,3,5-trphenyltetrazolium chloride monohydrate (TTC) staining and behavioral scoring were performed. CBF was recorded in the infarct lesion area and the corresponding contralateral area, and the affected/contralateral relative values (rCBF) were calculated to compare the differences in rCBF between different groups. The pathological changes in brain tissues were observed by HE staining, and the expression of vascular endothelial growth factor (VEGF) and platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) in brain tissues was detected by immunofluorescence and real-time quantitative polymerase chain reaction (RT-qPCR). The protein expression of VEGF was detected by western blotting.

Results

Hypertension and internal carotid atherosclerosis are high-risk factors for ischemic stroke, and CBF values in the infarct area are significantly lower than those in the corresponding areas on the contralateral side. NIHSS and mRS scores and CBF values have higher specificity and sensitivity for the prognosis of patients with AIS. LRP significantly reduces the infarct area, improves behavioral deficits in rats with cerebral ischemia, reduces neurological injury and histological damage, protects vascular structures, and promotes neovascularization. In addition, 3D-ASL showed a significant increase in brain tissue perfusion in the ischemic area after LRP, and the expression of VEGF and CD31 showed a significant positive correlation with CBF values.

Conclusion

Three dimensional (3D) ASL can be used to evaluate LRP to improve stroke perfusion, and its protective effect may be closely related to LRP-induced vascular regeneration.

Four Decades of Ischemic Penumbra and Its Implication for Ischemic Stroke

The ischemic penumbra defined four decades ago has been the main battleground of ischemic stroke. The evolving ischemic penumbra concept has been providing insight for the development of vascular and cellular approaches as well as diagnostic tools for the treatment of ischemic stroke. rt-PA thrombolytic therapy to prevent the transition of ischemic penumbra to core has been approved for acute ischemic stroke within 3 h and was later recommended to extend to 4.5 h after symptom onset. Mechanical thrombectomy was introduced for the treatment of acute ischemic stroke with a therapeutic window of up to 24 h after stroke onset. Multiple modalities brain imaging techniques have been developed that provide guidance to define ischemic penumbra for reperfusion therapy in clinical practice. Cellular and molecular dissection of ischemic penumbra has been providing targets for the development of neuroprotective therapy for ischemic stroke. However, the dynamic nature of ischemic penumbra implicates that infarct core eventually expands into penumbra over time without reperfusion, dictating relative short therapeutic windows and limiting the impact of current reperfusion intervention. Entering the 5^th decade since the introduction, ischemic penumbra remains the main focus of ischemic stroke research and clinical practice. In this review, we summarized the evolving ischemic penumbra concept and its implication in the development of vascular and cellular interventions as well as diagnostic tools for acute ischemic stroke. In addition, we discussed future perspectives on expansion of the campaign beyond ischemic penumbra to develop treatment for ischemic stroke.

Dynamic capillary stalls in reperfused ischemic penumbra contribute to injury: A hyperacute role for neutrophils in persistent traffic jams

Ever since the introduction of thrombolysis and the subsequent expansion of endovascular treatments for acute ischemic stroke, it remains to be identified why the actual outcomes are less favorable despite recanalization. Here, by high spatio-temporal resolution imaging of capillary circulation in mice, we introduce the pathological phenomenon of dynamic flow stalls in cerebral capillaries, occurring persistently in salvageable penumbra after reperfusion. These stalls, which are different from permanent cellular plugs of no-reflow, were temporarily and repetitively occurring in the capillary network, impairing the overall circulation like small focal traffic jams. In vivo microscopy in the ischemic penumbra revealed leukocytes traveling slowly through capillary lumen or getting stuck, while red blood cell flow was being disturbed in the neighboring segments under reperfused conditions. Stall dynamics could be modulated, by injection of an anti-Ly6G antibody specifically targeting neutrophils. Decreased number and duration of stalls were associated with improvement in penumbral blood flow within 2-24 h after reperfusion along with increased capillary oxygenation, decreased cellular damage and improved functional outcome. Thereby, dynamic microcirculatory stall phenomenon can be a contributing factor to ongoing penumbral injury and is a potential hyperacute mechanism adding on previous observations of detrimental effects of activated neutrophils in ischemic stroke.

Outcomes after Thrombectomy for Minor Stroke: A Meta-Analysis

PURPOSE

To determine the outcomes after mechanical thrombectomy (MT) versus medical management in patients with minor stroke symptomatology.

METHODS

A meta-analysis was performed for studies reporting outcomes after MT, either as stand-alone therapy or with intravenous thrombolysis in patients with minor stroke and large-vessel occlusion.

RESULTS

Fourteen studies with 2134 patients met the selection criteria and were included. Two studies compared immediate thrombectomy versus best medical management (with rescue thrombectomy) and the odds ratios of excellent outcomes, good outcomes, mortality and incidence of symptomatic intracranial hemorrhage (sICH) after immediate thrombectomy versus best medical management were 1.07 (95% confidence interval [CI] 0.93-1.22%), 1.15 (95% CI 1.05-1.25), 0.65 (95% CI 0.30-1.38), and 2.89 (95% CI 0.82-10.13), respectively. Among the 8 studies that compared MT outcomes versus medical management (without thrombectomy), odds ratios of excellent outcomes, good outcomes, mortality, and incidence of sICH after MT versus medical management were 0.98 (95% CI 0.89-1.07), 0.94 (95% CI 0.89-1.00), 1.61 (95% CI 1.08-2.41), and 2.59 (95% CI 1.35-4.96), respectively. Among all 14 studies, pooled proportions of excellent outcomes, good outcomes, mortality, and sICH after thrombectomy were 58.7%, 76.2%, 6.82%, and 3.23%, respectively.

CONCLUSIONS

Our study shows significant selection bias and heterogeneity in the literature with differences in baseline characteristics (age, stroke severity, prestroke modified Rankin Scale score, side of infarct, vessel and site of occlusion, use of intravenous thrombolysis, criteria for clinical deterioration, and selection bias for rescue MT and rates of reperfusion), emphasizing the need for a randomized controlled trial.

More expansive horizons: a review of endovascular therapy for patients with low NIHSS scores

While the landmark 2015 stroke trials demonstrated that endovascular therapy (EVT) was superior to medical management for the treatment of acute ischemic stroke due to large vessel occlusion, the efficacy of EVT for patients presenting with a low NIHSS score remains undetermined. We conducted a review of the EVT low National Institutes of Health Stroke Scale (NIHSS) stroke literature, identifying 24 quantitative and six qualitative publications. Details of study designs and outcome were extracted and critically discussed.All identified qualitative studies were retrospective. There was significant study design heterogeneity, with 18 unique study designs between the 24 identified quantitative manuscripts. Study investigations included low NIHSS EVT feasibility (n=6), EVT versus best medical management (BMM; n=10), EVT versus intravenous therapy (IVT, n=3), and low NIHSS score versus high NIHSS score (n=3). From single-arm EVT feasibility studies, the reported ranges of modified Thrombolysis in Cerebral Infarction and symptomatic intracranial hemorrhage were 78-97% and 0-10%, respectively. The EVT versus BMM literature had heterogeneous results with 40% reporting benefit with EVT and 60% reporting neutral findings. None of the studies comparing EVT with IVT reported a difference between the two revascularization therapies. The four identified meta-analyses had incongruent inclusion criteria and conflicting results. Two randomized trials are currently investigating EVT in patients with a low NIHSS score. Selected meta-analyses do suggest a potential benefit of EVT over BMM; however, current and future randomized clinical trials will better elucidate the efficacy of EVT in this patient population.

Thrombectomy vs medical management in low NIHSS acute anterior circulation stroke

OBJECTIVE

To undertake an effectiveness and safety analysis of EVT in patients with LVO and NIH Stroke Scale (NIHSS) score ≤6 using datasets of multicenter and multinational nature.

METHODS

We pooled patients with anterior circulation occlusion from 3 prospective international cohorts. Patients were eligible if presentation occurred within 12 hours from last known well and baseline NIHSS ≤6. Primary outcome was modified Rankin Scale (mRS) score 0-1 at 90 days. Secondary outcomes included neurologic deterioration at 24 hours (change in NIHSS of ≥2 points), mRS 0-2 at 90 days, and 90-day all-cause mortality. We used propensity score matching to adjust for nonrandomized treatment allocation.

RESULTS

Among 236 patients who fit inclusion criteria, 139 received EVT and 97 received medical management. Compared to medical management, the EVT group was younger (65 vs 72 years; p < 0.001), had more proximal occlusions (p < 0.001), and less frequently received concurrent IV thrombolysis (57.7% vs 71.2%; p = 0.04). After propensity score matching, clinical outcomes between the 2 groups were not significantly different. EVT patients had an 8.6% (95% confidence interval [CI] -8.8% to 26.1%) higher rate of excellent 90-day outcome, despite a 22.3% (95% CI, 3.0%-41.6%) higher risk of neurologic deterioration at 24 hours.

CONCLUSIONS

EVT for LVO in patients with low NIHSS score was associated with increased risk of neurologic deterioration at 24 hours. However, both EVT and medical management resulted in similar proportions of excellent clinical outcomes at 90 days.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that for patients with acute anterior circulation ischemic strokes and LVO with NIHSS < 6, EVT and medical management result in similar outcomes at 90 days.

May endovascular thrombectomy without CT perfusion improve clinical outcome?

BACKGROUND

DAWN and DEFUSE-3 trials demonstrated the benefit of endovascular thrombectomy in late-presenting acute ischemic strokes due to anterior circulation large vessel occlusion. The aim of our study is to evaluate results of endovascular thrombectomy in large intracranial vessel occlusion without perfusion CT patient selection.

METHODS

we reviewed our prospectively collected endovascular databases for patients with an acute stroke from March 2016 to October 2018, treated after 6 h from stroke onset, without perfusion CT selection. Baseline characteristics, procedural data, and outcomes were evaluated. A good outcome was defined as a 90-day modified Rankin Scale score of 0-2. The association between clinical and procedural parameters and functional outcome was assessed.

RESULTS

out of 212 patients 55 were treated after 6 h from stroke onset, 49 of which for an anterior circulation occlusion. 18/49 were functional independent at 90 days (mRS 0-2), Successful recanalization (mTICI 2b to 3) was achieved in 38/49 patients (77 %). Multivariate logistic regression indicated that a low baseline NIHSS was associated with favorable outcome (OR 0.66, 95 % CI 0.52-0.83, p-value 0.001).

CONCLUSIONS

in our retrospective analysis, baseline NIHSS is the only parameter that can predict good outcome (90-days mRS 0-2). We confirm data from recent papers assessing that perfusion CT can provide a better patients' selection compared to mCTA for large vessels occlusion treated beyond six hours from symptom onset.

Endovascular versus medical therapy for large-vessel anterior occlusive stroke presenting with mild symptoms

Background

Acute ischemic stroke patients with a large-vessel occlusion but mild symptoms (NIHSS ≤ 6) pose a treatment dilemma between medical management and endovascular thrombectomy.

Aims

To evaluate the differences in clinical outcomes of endovascular thrombectomy-eligible patients with target-mismatch perfusion profiles who undergo either medical management or endovascular thrombectomy.

Methods

Forty-seven patients with acute ischemic stroke due to large-vessel occlusion, NIHSS ≤ 6, and a target-mismatch perfusion imaging profile were included. Patients underwent medical management or endovascular thrombectomy following treating neurointerventionalist and neurologist consensus. The primary outcome measure was NIHSS shift. Secondary outcome measures were symptomatic intracranial hemorrhage, in-hospital mortality, and 90-day mRS scores. The primary intention-to-treat and as-treated analyses were compared to determine the impact of crossover patient allocation on study outcome measures.

Results

Forty-seven patients were included. Thirty underwent medical management (64%) and 17 underwent endovascular thrombectomy (36%). Three medical management patients underwent endovascular thrombectomy due to early clinical deterioration. Presentation NIHSS ( P = 0.82), NIHSS shift ( P = 0.62), and 90-day functional independence (mRS 0–2; P = 0.25) were similar between groups. Endovascular thrombectomy patients demonstrated an increased overall rate of intracranial hemorrhage (35.3% vs. 10.0%; P = 0.04), but symptomatic intracranial hemorrhage was similar between groups ( P = 0.25). In-hospital mortality was similar between groups ( P = 0.46), though all two deaths in the medical management group occurred among crossover patients. Endovascular thrombectomy patients demonstrated a longer length of stay (7.6 ± 7.2 vs. 4.3 ± 3.9 days; P = 0.04) and a higher frequency of unfavorable discharge to a skilled-nursing facility ( P = 0.03) rather than home ( P = 0.05).

Conclusions

Endovascular thrombectomy may pose an unfavorable risk-benefit profile over medical management for endovascular thrombectomy-eligible acute ischemic stroke patients with mild symptoms, which warrants a randomized trial in this subpopulation.

Efficacy and safety of endovascular thrombectomy in mild ischemic stroke: results from a retrospective study and meta-analysis of previous trials

Background

Mechanical thrombectomy has been proven as a standard care for moderate to severe ischemic stroke with anterior large vessel occlusion (LVO); however, whether it is equally effective in mild ischemic stroke (MIS) is controversial.

Methods

In this retrospective study, a total of 177 Chinese patients presenting with MIS (NIHSS ≤8) and LVO between January 2014 and September 2017 from seven comprehensive stroke centers were identified. Odds of good outcome with endovascular thrombectomy versus medical treatment were obtained by logistic regression analysis and propensity-score matching method, and a meta-analysis pooled results from six studies (n = 733).

Results

Good outcome (mRS: 0–1) was 58.2% (46/79) in the thrombectomy and 46.9% (46/98) in the medical group, which showed no statistical significance before adjustment (P = 0.13; OR = 1.57, 95% CI: 0.86 to 2.86). The adjusted ORs of thrombectomy versus medical group were 3.23 (95% CI, 1.35 to 7.73; P = 0.008) by multivariable logistic analysis, 2.78 (1.12 to 6.89; P = 0.02) by propensity score matching analysis, and 3.20 (1.22 to 8.37; P = 0.01) by propensity score matching analysis with additional adjustments, respectively. Thrombectomy treatment did not result in excessive mortality or symptomatic intracranial hemorrhage after adjustments. The meta-analysis did not confirm the associations between good outcome and endovascular treatment.

Conclusions

The current study indicates that endovascular thrombectomy is associated with good functional outcome in MIS patients with LVO, and without additional risk of symptomatic intracranial hemorrhage and mortality. Although the meta-analysis failed to demonstrate its superiority compared to medical treatment, randomized clinical trials are needed.

Electronic supplementary material

The online version of this article (10.1186/s12883-019-1372-9) contains supplementary material, which is available to authorized users.

[Reperfusion therapy in patients with minor or mild ischemic stroke]

A significant number of patients with minor or mild stroke symptoms on initial presentation subsequently develop neurological deterioration and poor clinical outcomes at hospital discharge. The presence of an underlying large vessel occlusion is a strong predictor of both clinical worsening and poor outcome. Although patients with a low baseline National Institutes of Health Stroke Scale (NIHSS) could have been included in some randomized controlled trials, the benefits of the mechanical thrombectomy for patients with a low NIHSS score are unknown. The causes of neurological deterioration in patients with underlying large vessel occlusion are heterogeneous, but include collateral failure, and no straightforward mechanisms are found in the majority of cases. Patients with internal carotid artery occlusion, but with a patent middle cerebral artery (MCA), can occasionally have good collateral circulation and develop only minor or mild stroke. These patients exhibit collateral MCA flow via the circle of Willis despite ipsilateral internal carotid artery occlusion. However, thrombus migration may cause occlusion of collateral MCA flow, leading to dramatic neurological deterioration. Careful observation and detailed assessment are required for the management of these patients. Recent studies have examined the efficacy and optimal timing of thrombolysis or mechanical thrombectomy for patients with minor or mild stroke. Herein, we review the mechanisms of neurological deterioration, and the efficacy of reperfusion therapy, for patients with minor or mild stroke.

Thrombectomy for Stroke at 6-24 hours without Perfusion CT Software for Patient Selection

BACKGROUND

Although, thrombectomy for stroke more than 6 hours after onset supported by automated perfusion computed tomography (CT) software (RAPID, iSchemaView) is effective, this software is not available in Japan. This study aimed to elucidate the efficacy of thrombectomy 6-24 hours after onset in our patient cohort using conventional imaging mismatch.

METHODS

Of 586 ischemic stroke patients who underwent thrombectomy registered from January 2015 to December 2017, patients with occlusion of the intracranial internal carotid artery or middle cerebral artery, who had last been known to be well 6-24 hours earlier and who had a prestroke modified Rankin scale (mRS) score 0 or 1 were enrolled. Clinical outcomes were the scores of the utility-weighted (UW) mRS, which ranges from 0 (death) to 10 (no symptom or disability), and the rate of functional independence (mRS score of 0-2) at 90 days.

RESULTS

This study sample included 31 patients. The median baseline National Institutes of Health Stroke Scale score was 17 (interquartile range [IQR], 13-20), and the median Diffusion-Weighted Imaging-Alberta Stroke Program Early CT Score was 7 (IQR, 5-8). The median interval between the time that the patient was last known well and revascularization was 741 (IQR, 641-818) minutes. The mean UW mRS score at 90 days was 5.3, the rate of functional independence was 32%, and the 90-day mortality rate was 13%.

CONCLUSIONS

Thrombectomy 6-24 hours after onset which can be performed with conventional imaging mismatch might be secured for improving functional independence in stroke patients.