Meta-analysis of Vascular Imaging Features to Predict Outcome Following Intravenous rtPA for Acute Ischemic Stroke

The correlation between intracranial arterial calcification and the outcome of reperfusion therapy

OBJECTIVE

Intracranial arterial calcification (IAC) is a risk factor of ischemic stroke. However, the relationship between IAC patterns and clinical outcome of ischemic stroke remains controversial. We aimed to investigate the correlation between IAC patterns and the effects of reperfusion therapy among acute stroke patients.

METHODS

Consecutive acute ischemic stroke patients who underwent reperfusion therapy were included. IAC was categorized as intimal or medial. Based on its involvement, IAC was further classified as diffuse or focal. Neurologic dysfunction was assessed by the National Institute of Health stroke scale (NIHSS). Clinical outcome including favorable neurologic outcome (FNO) and early neurologic deterioration (END) were assessed.

RESULTS

Of 130 patients, 117 had IAC. Intimal IAC was identified in 74.6% of patients and medial IAC was present in 64.6% of patients. Diffuse IAC was present in 31.5% of patients. All diffuse IACs were medial pattern. Diffuse IAC was associated with higher baseline NIHSS (p = 0.011) and less FNO (p = 0.047). Compared with patients with focal or single diffuse IAC, patients with multiple diffuse IAC had higher baseline NIHSS (p = 0.002) and less FNO (p = 0.024). Multivariable linear regression (p < 0.001) and logistic regression (p = 0.027) suggested that multiple diffuse IAC was associated with higher baseline NIHSS and less FNO. No significant association was found between END and different IAC patterns.

INTERPRETATION

Multiple diffuse medial IAC may predict severer neurologic dysfunction and less favorable neurologic outcome after reperfusion therapy in acute stroke patients.

Review of studies on dynamic cerebral autoregulation in the acute phase of stroke and the relationship with clinical outcome

Acute stroke is associated with high morbidity and mortality. In the last decades, new therapies have been investigated with the aim of improving clinical outcomes in the acute phase post stroke onset. However, despite such advances, a large number of patients do not demonstrate improvement, furthermore, some unfortunately deteriorate. Thus, there is a need for additional treatments targeted to the individual patient. A potential therapeutic target is interventions to optimize cerebral perfusion guided by cerebral hemodynamic parameters such as dynamic cerebral autoregulation (dCA). This narrative led to the development of the INFOMATAS (Identifying New targets FOr Management And Therapy in Acute Stroke) project, designed to foster interventions directed towards understanding and improving hemodynamic aspects of the cerebral circulation in acute cerebrovascular disease states. This comprehensive review aims to summarize relevant studies on assessing dCA in patients suffering acute ischemic stroke, intracerebral haemorrhage, and subarachnoid haemorrhage. The review will provide to the reader the most consistent findings, the inconsistent findings which still need to be explored further and discuss the main limitations of these studies. This will allow for the creation of a research agenda for the use of bedside dCA information for prognostication and targeted perfusion interventions.

Distinctive Gut Microbiota Alteration Is Associated with Poststroke Functional Recovery: Results from a Prospective Cohort Study

Objectives

Functional prognosis is potentially correlated with gut microbiota alterations following the dysregulation of the gut-microbiota-brain axis after stroke. This study was designed to explore the poststroke alterations of gut microbiota and potential correlations between gut microbiota and global functions.

Methods

A total of thirty-eight patients with stroke and thirty-five healthy demographics-matched controls were recruited. Their fecal DNAs were extracted, and the V3-V4 regions of the conserved bacterial 16S RNA were amplified and sequenced on the Illumina MiSeq platform. Microbial composition, diversity indices, and species cooccurrence were compared between groups. Random forest and receiver operating characteristic analysis were used to identify potential diagnostic biomarkers. Relationships between discriminant bacteria and poststroke functional outcomes were estimated.

Results

Higher alpha diversity of gut microbiota was observed in poststroke patients as compared to the healthy controls (p < 0.05). Beta diversity showed that microbiota composition in the poststroke group was significantly different from that in the control group. Relative abundance of nine genera increased significantly in poststroke patients, while 82 genera significantly decreased (p < 0.05). The accuracy, specificity, and susceptibility of the optimal model consisted of the top 10 discriminant species were 93%, 100%, and 86%, respectively. Subgroup analysis showed that bacterial taxa abundant between subacute and chronic stroke patients were overall different (p < 0.05). The modified Rankin scale (mRS) (r = −0.370, p < 0.05), Fugl-Meyer assessment (FMA) score (r = 0.364, p < 0.05), water swallow test (WST) (r = 0.340, p < 0.05), and Barthel index (BI) (r = 0.349, p < 0.05) were significantly associated with alterations of distinctive gut microbiota.

Conclusions

The gut microbiota in patients with stroke was significantly changed in terms of richness and composition. Significant associations were detected between alterations of distinctive gut microbiota and global functional prognosis. It would facilitate novel treatment target selection in the context of stroke while the causal relationships between distinctive gut microbiota alterations and functional variations need to be further verified with well-designed studies.

Eprosartan: A closer insight into its neuroprotective activity in rats with focal cerebral ischemia-reperfusion injury

Eprosartan (EPRO), an angiotensin receptor type-1 (AT-1) blocker, exhibited neuroprotective activities in ischemic stroke resulting from focal cerebral ischemia in rats. The current study aimed to clarify the neuroprotective role of EPRO in middle carotid artery occlusion (MCAO)-induced ischemic stroke in rats. Fifty-six male Wistar rats were divided into four groups (n = 14 per group): sham-operated group, sham receiving EPRO (60 mg/kg/day, po) group, ischemia-reperfusion (IR) group, and IR receiving EPRO (60 mg/kg/day, po) group. MCAO led to a remarkable impairment in motor function together with stimulation of inflammatory and apoptotic pathways in the hippocampus of rats. After MCAO, the AT1 receptor in the brain was stimulated, resulting in activation of Janus kinase 2/signal transducers and activators of transcription 3 signaling generating more neuroinflammatory milieu and destructive actions on the hippocampus. Augmentation of caspase-3 level by MCAO enhanced neuronal apoptosis synchronized with neurodegenerative effects of oxidative stress biomarkers. Pretreatment with EPRO opposed motor impairment and decreased oxidative and apoptotic mediators in the hippocampus of rats. The anti-inflammatory activity of EPRO was revealed by downregulation of nuclear factor-kappa B and tumor necrosis factor-β levels and (C-X-C motif) ligand 1 messenger RNA (mRNA) expression. Moreover, the study confirmed the role of EPRO against a unique pathway of hypoxia-inducible factor-1α and its subsequent inflammatory mediators. Furthermore, upregulation of caveolin-1 mRNA level was also observed along with decreased oxidative stress marker levels and brain edema. Therefore, EPRO showed neuroprotective effects in MCAO-induced cerebral ischemia in rats via attenuation of oxidative, apoptotic, and inflammatory pathways.

Cerebral autoregulation and response to intravenous thrombolysis for acute ischemic stroke

We hypothesized that knowledge of cerebral autoregulation (CA) status during recanalization therapies could guide further studies aimed at neuroprotection targeting penumbral tissue, especially in patients that do not respond to therapy. Thus, we assessed CA status of patients with acute ischemic stroke (AIS) during intravenous r-tPA therapy and associated CA with response to therapy. AIS patients eligible for intravenous r-tPA therapy were recruited. Cerebral blood flow velocities (transcranial Doppler) from middle cerebral artery and blood pressure (Finometer) were recorded to calculate the autoregulation index (ARI, as surrogate for CA). National Institute of Health Stroke Score was assessed and used to define responders to therapy (improvement of ≥ 4 points on NIHSS measured 24–48 h after therapy). CA was considered impaired if ARI < 4. In 38 patients studied, compared to responders, non-responders had significantly lower ARI values (affected hemisphere: 5.0 vs. 3.6; unaffected hemisphere: 5.4 vs. 4.4, p = 0.03) and more likely to have impaired CA (32% vs. 62%, p = 0.02) during thrombolysis. In conclusion, CA during thrombolysis was impaired in patients who did not respond to therapy. This variable should be investigated as a predictor of the response to therapy and to subsequent neurological outcome.

Risk Factors Associated with Outcomes of Recombinant Tissue Plasminogen Activator Therapy in Patients with Acute Ischemic Stroke

Ischemic stroke is the most common type of stroke, and early interventional treatment is associated with favorable outcomes. In the guidelines, thrombolytic therapy using recombinant tissue-type plasminogen activator (rt-PA) is recommended for eligible patients with acute ischemic stroke. However, the risk of hemorrhagic complications limits the use of rt-PA, and the risk factors for poor treatment outcomes need to be identified. To identify the risk factors associated with in-hospital poor outcomes in patients treated with rt-PA, we analyzed the electronic medical records of patients who were diagnosed with acute ischemic stroke and treated for rt-PA at Chang Gung Memorial Hospitals from 2006 to 2016. In-hospital death, intensive care unit (ICU) stay, or prolonged hospitalization were defined as unfavorable treatment outcomes. Medical history variables and laboratory test results were considered variables of interest to determine risk factors. Among 643 eligible patients, 537 (83.5%) and 106 (16.5%) patients had favorable and poor outcomes, respectively. In the multivariable analysis, risk factors associated with poor outcomes were female gender, higher stroke severity index (SSI), higher serum glucose levels, lower mean corpuscular hemoglobin concentration (MCHC), lower platelet counts, and anemia. The risk factors found in this research could help us study the treatment strategy for ischemic stroke.

Acute symptomatic extracranial internal carotid occlusion - natural course and clinical impact

Background: To assess the vascular and clinical course of acute symptomatic extracranial internal carotid artery (ICA) occlusion. Patients and methods: Patients with an acute ischemic event in the anterior circulation and corresponding extracranial ICA occlusion at CT angiography and/or color-coded duplex sonography underwent recurrent duplex follow-up for detection of spontaneous recanalization. Stroke recurrence and functional outcome 4.5 months after the ischemic index event assessed by modified Rankin scale served as secondary outcome parameters. Results: 133 patients (91 men, mean age 62.3 years, SD 10.8) demonstrated symptomatic occlusion of the extracranial ICA with open intracranial ICA and open middle cerebral artery and were followed-up for spontaneous recanalization. Twenty-eight recanalized spontaneously, 25 to high-grade focal stenosis within 12 days, revealing an early cumulative recanalization rate of 23 %. Detection of recanalization was independently associated with de novo dual anti-platelet therapy (adjusted odds ratio [OR], 3.24; 95 % confidence interval [CI], 1.34 to 7.80). Ischemic recurrence occurred in 16 patients, of which 10 deemed to be embolic and 5 hemodynamic. Spontaneous ICA recanalization and an exhausted cerebrovascular reserve in the hemisphere distal to the occluded ICA were both independently associated with the occurrence of a recurrent ischemic event at Cox regression. An increasing NIHSS score at admission, a decreasing middle cerebral artery flow velocity and an ischemic recurrence independently predicted poor outcome (modified Rankin scale 3 to 6) in multivariate analysis. Conclusions: Acute symptomatic extracranial ICA occlusion is an unstable condition with frequent spontaneous recanalization to severe stenosis and early embolic stroke recurrence, demanding appropriate prevention especially in those patients with only mild deficit.

Carotid duplex parameters to predict long term outcomes of ischemic stroke patients receiving intra-arterial thrombectomy treatment

Early treatment of acute ischemic stroke with intravenous thrombolysis therapy (ITT) followed by intra-arterial thrombectomy (IAT) is a promising new treatment option for improving functional outcomes. Identifying patients who will benefit from this treatment combination is important.A total of 92 acute ischemic stroke patients who received ITT and IAT with a minimum of 1-year follow-up were included in the study. All parameters of clinical and imaging examinations at baseline were examined which parameters were significantly correlated with the 1-year functional outcomes (modified Rankin scale [mRS], National Institute of Health Stroke Scale [NIHSS], and Barthel Index) after stroke. Receiver-operating characteristic (ROC) curves analysis was performed to estimate the diagnostic performance of each significantly related parameter. Youden index was used to determine the optimal threshold value. Multivariate logistic regression model analyses were applied to verify the results of predicting the favorable functional outcomes.Immediate postoperation outcome with modified thrombolysis in cerebral infarction grading showed that total of 62 patients qualified for satisfactory result (2b or 3). In predicting NIHSS improvement, ROC curve analysis showed that a cutoff point of vertebral artery pulsatility index (VA PI)-ipsilateral ≤2.3 yields the best diagnostic performance (area under the ROC curve [AUC] = 0.728); in predicting mRS improvement, VA PI-ipsilateral ≤1.92 and internal carotid artery resistance index (ICA RI)-ipsilateral ≤0.71 yield good diagnostic performance (AUC = 0.697 and 0.672, respectively); and ICA RI-contralateral ≤0.70 or plaque index-ipsilateral ≤2 had better diagnostic accuracy (AUC = 0.764 and 0.689, respectively) than other indices to predict Barthel index improvement. The multivariate analysis also showed that these 5 indices were those more powerful and highly significant favorable functional outcomes predictors.Parameters of pulsatility and resistance index from carotid duplex could be easily accessed and noninvasive. The outcome of ischemic stroke patients receiving ITT followed by IAT can be forecasted by these 2 crucial predictors that hint the patients' functional outcomes as well as guiding first line in-charge clinician in terms of decision making.

Notch signaling and neuronal death in stroke

Ischemic stroke is a leading cause of morbidity and death, with the outcome largely determined by the amount of hypoxia-related neuronal death in the affected brain regions. Cerebral ischemia and hypoxia activate the Notch1 signaling pathway and four prominent interacting pathways (NF-κB, p53, HIF-1α and Pin1) that converge on a conserved DNA-associated nuclear multi-protein complex, which controls the expression of genes that can determine the fate of neurons. When neurons experience a moderate level of ischemic insult, the nuclear multi-protein complex up-regulates adaptive stress response genes encoding proteins that promote neuronal survival, but when ischemia is more severe the nuclear multi-protein complex induces genes encoding proteins that trigger and execute a neuronal death program. We propose that the nuclear multi-protein transcriptional complex is a molecular mediator of neuronal hormesis and a target for therapeutic intervention in stroke.

Outcome After Reperfusion Therapies in Patients With Large Baseline Diffusion-Weighted Imaging Stroke Lesions

Background and Purpose—

Stroke patients with large diffusion-weighted imaging (DWI) volumes are often excluded from reperfusion because of reckoned futility. In those with DWI volume >70 mL, included in the THRACE trial (Mechanical Thrombectomy After Intravenous Alteplase Versus Alteplase Alone After Stroke), we report the associations between baseline parameters and outcome.

Methods—

We examined 304 patients with anterior circulation stroke and pretreatment magnetic resonance imaging. Variables were extracted from the THRACE database, and DWI volumes were measured semiautomatically.

Results—

Among 53 patients with DWI volume >70 mL, 12 had favorable outcome (modified Rankin Scale score, ≤2) at 3 months; they had less coronary disease (0/12 versus 12/38; P =0.046) and less history of smoking (1/10 versus 12/31; P =0.013) than patients with modified Rankin Scale score >2. None of the 8 patients >75 years of age reached modified Rankin Scale score ≤2. Favorable outcome occurred in 12 of 37 M1-occluded patients but in 0 of 16 internal carotid-T/L–occluded patients ( P =0.010). Favorable outcome was more frequent (6/13) when DWI lesion was limited to the superficial middle cerebral artery territory than when it extended to the deep middle cerebral artery territory (6/40; P =0.050).

Conclusions—

Stroke patients with DWI lesion >70 mL may benefit from reperfusion therapy, especially those with isolated M1 occlusion or ischemia restricted to the superficial middle cerebral artery territory. The benefit of treatment seems questionable for patients with carotid occlusion or lesion extending to the deep middle cerebral artery territory.

Successful Reperfusion With Intravenous Thrombolysis Preceding Mechanical Thrombectomy in Large-Vessel Occlusions

BACKGROUND AND PURPOSE

Although current guidelines advocate pretreatment with intravenous thrombolysis (IVT) in all eligible patients with acute ischemic stroke with large-vessel occlusion before mechanical thrombectomy, there are observational data questioning the efficacy of this approach. One of the main arguments in favor of IVT pretreatment is the potential for tissue-type plasminogen activator-induced successful reperfusion (SR) before the onset of endovascular procedure.

METHODS

We performed a systematic review and meta-analysis of randomized controlled clinical trials and observational cohorts providing rates of SR with IVT in patients with large-vessel occlusion before the initiation of mechanical thrombectomy. We also performed subgroup analyses according to study type (randomized controlled clinical trials versus observational) and according to the inclusion per protocol of patients with tandem (intracranial/extracranial) occlusions.

RESULTS

We identified 13 eligible studies (7 randomized controlled clinical trials and 6 observational cohorts), including 1561 patients with acute ischemic stroke (median National Institutes of Health Stroke Scale score, 17) with large-vessel occlusion. SR following IVT and before mechanical thrombectomy was documented in 11% (95% confidence interval, 7%-16%), with no difference among cohorts derived from randomized controlled clinical trials and observational studies. There was significant heterogeneity across included studies both in the overall analysis and among subgroups (I²>84%; P for Cochran Q, <0.001). Higher tissue-type plasminogen activator-induced SR rates were documented in studies reporting the exclusion of tandem occlusions (17%; 95% confidence interval, 11%-23%) compared with the rest (7%; 95% confidence interval, 4%-11%; P for subgroup differences, 0.003).

CONCLUSIONS

Pretreatment with systemic thrombolysis in patients with large-vessel occlusion eligible for mechanical thrombectomy results in SR in 1 of 10 cases, negating the need for additional endovascular reperfusion. Tandem occlusions seem to be the least responsive to IVT pretreatment.

Recanalisation therapy in patients with acute ischaemic stroke caused by large artery occlusion: choice of therapeutic strategy according to underlying aetiological mechanism?

Various mechanisms underlie causative large artery occlusion (LAO) in patients with acute ischaemic stroke. Cardioembolic and atherosclerotic occlusions are the two most common types. The pathophysiological changes and responses to mechanical thrombectomy (MT) and antithrombotic treatments including thrombolysis, antiplatelet and anticoagulation therapy may vary among patients with different aetiological mechanisms of occlusion. Atherosclerotic occlusion is inclined to have relatively abundant collaterals and larger area of penumbra, hence a relatively wider time window for reperfusion therapy, while poor response to medical thrombolysis and MT. Severe residual stenosis and reocclusion occurred frequently after MT in atherosclerotic LAO. Angioplasty and stenting as rescue or the first-line therapy and more intensified antiplatelet therapy beyond related recommendations in the current guidelines are sometimes used in managing acute causative LAO because of poor recanalisation after recommended standard thrombolysis or MT therapy, which are usually based on individual experience. Standard protocol to establish emergent aetiological diagnosis of causative LAO and individualised aetiology-specific treatment strategy is needed.

Impact of leukoaraiosis on parenchymal hemorrhage in elderly patients treated with thrombolysis

INTRODUCTION

Severity of vascular damage of white matter may predict hemorrhagic transformation (HT). We assess the relationship between leukoaraiosis (LA) severity and the type of hemorrhagic transformation in elderly patients treated with thrombolysis.

METHODS

We retrospectively analyzed the clinical data and pretreatment magnetic resonance imaging (MRI) of 180 consecutive ischemic stroke patients aged over 75 years. LA severity was graded according to the Fazekas scale, and acute diffusion-weighted-imaging (DWI) lesion volumes were semi-automatically outlined. Predictors of hemorrhagic infarction (HI) and parenchymal hemorrhage (PH) were identified using logistic regression analysis and exact multinomial logistic analysis.

RESULTS

HT occurred in 31 patients (17 %). Baseline National Institute of Health Stroke Score (NIHSS; p = 0.008), severe LA (p = 0.02), and diffusion lesion volume (p = 0.02) were predictors of HT in univariable logistic regression. Adjusted to lesion volume and baseline NIHSS score, exact multinomial logistic analysis showed that severe LA was the only independent predictor of parenchymal hemorrhage (p = 0.03).

CONCLUSION

In elderly patients, LA severity better predicts parenchymal hemorrhage than infarct size.