Intravenous ancrod for treatment of acute ischemic stroke: the STAT study: a randomized controlled trial. Stroke Treatment with Ancrod Trial

Beta spending function based on conditional power in group sequential design

Conditional power (CP) serves as a widely utilized approach for futility monitoring in group sequential designs. However, adopting the CP methods may lead to inadequate control of the type II error rate at the desired level. In this study, we introduce a flexible beta spending function tailored to regulate the type II error rate while employing CP based on a predetermined standardized effect size for futility monitoring (a so-called CP-beta spending function). This function delineates the expenditure of type II error rate across the entirety of the trial. Unlike other existing beta spending functions, the CP-beta spending function seamlessly incorporates beta spending concept into the CP framework, facilitating precise stagewise control of the type II error rate during futility monitoring. In addition, the stopping boundaries derived from the CP-beta spending function can be calculated via integration akin to other traditional beta spending function methods. Furthermore, the proposed CP-beta spending function accommodates various thresholds on the CP-scale at different stages of the trial, ensuring its adaptability across different information time scenarios. These attributes render the CP-beta spending function competitive among other forms of beta spending functions, making it applicable to any trials in group sequential designs with straightforward implementation. Both simulation study and example from an acute ischemic stroke trial demonstrate that the proposed method accurately captures expected power, even when the initially determined sample size does not consider futility stopping, and exhibits a good performance in maintaining overall type I error rates for evident futility.

Global trends and research hotspots of stroke and magnetic resonance imaging: A bibliometric analysis

BACKGROUND

In this study, we used CiteSpace and VOSviewer to create a bibliometric visualization of research papers relating to stroke and magnetic resonance imaging (MRI) between 2000 and 2022. To fully understand the trends and hotspots in MRI and stroke research and provide new perspectives for future studies.

METHODS

The Web of Science Core Collection was selected as the source of data for this paper. Using CiteSpace and VOSviewer, publications were analyzed for authors, countries, institutions, journals, references, and keywords.

RESULTS

We found 1423 papers after searching and removing duplicates, which indicated an upward trend over the previous 23 years. Fiebach J.B. is the most published author (21 publications), Hacke W. is the most cited author (213 citations), and the United States (449 publications) and Harvard University (86 publications) are the most prolific nations and institutions. Stroke is the journal with the most co-citations (1275) and the most papers (171) published. The most representative reference was the 1995 article by Marler et al, which received 115 citations and had the top 3 co-occurring keywords: stroke, magnetic resonance imaging, and MRI. The article by Nogueria et al showed the strongest citation burst at the end of 2022 (strength = 17.32). High-frequency keywords in recent years are time, association, functional connectivity, thrombectomy, and rehabilitation.

CONCLUSION

This study provides a scientific perspective on stroke and MRI research, provides valuable information for researchers to understand the current status of research, hotspots, and trends, and guides future research directions.

De Novo Venom Gland Transcriptome Assembly and Characterization for Calloselasma rhodostoma (Kuhl, 1824), the Malayan Pit Viper from Malaysia: Unravelling Toxin Gene Diversity in a Medically Important Basal Crotaline

In Southeast Asia, the Malayan Pit Viper (Calloselasma rhodostoma) is a venomous snake species of medical importance and bioprospecting potential. To unveil the diversity of its toxin genes, this study de novo assembled and analyzed the venom gland transcriptome of C. rhodostoma from Malaysia. The expression of toxin genes dominates the gland transcriptome by 53.78% of total transcript abundance (based on overall FPKM, Fragments Per Kilobase Million), in which 92 non-redundant transcripts belonging to 16 toxin families were identified. Snake venom metalloproteinase (SVMP, PI > PII > PIII) is the most dominant family (37.84% of all toxin FPKM), followed by phospholipase A₂ (29.02%), bradykinin/angiotensin-converting enzyme inhibitor-C-type natriuretic peptide (16.30%), C-type lectin (CTL, 10.01%), snake venom serine protease (SVSP, 2.81%), L-amino acid oxidase (2.25%), and others (1.78%). The expressions of SVMP, CTL, and SVSP correlate with hemorrhagic, anti-platelet, and coagulopathic effects in envenoming. The SVMP metalloproteinase domains encode hemorrhagins (kistomin and rhodostoxin), while disintegrin (rhodostomin from P-II) acts by inhibiting platelet aggregation. CTL gene homologues uncovered include rhodocytin (platelet aggregators) and rhodocetin (platelet inhibitors), which contribute to thrombocytopenia and platelet dysfunction. The major SVSP is a thrombin-like enzyme (an ancrod homolog) responsible for defibrination in consumptive coagulopathy. The findings provide insight into the venom complexity of C. rhodostoma and the pathophysiology of envenoming.

Fibrinogen and Factor XIII in Venous Thrombosis and Thrombus Stability

As the third most common vascular disease, venous thromboembolism is associated with significant mortality and morbidity. Pathogenesis underlying venous thrombosis is still not fully understood. Accumulating data suggest fibrin network structure and factor XIII-mediated crosslinking are major determinants of venous thrombus mass, composition, and stability. Understanding the cellular and molecular mechanisms mediating fibrin(ogen) and factor XIII production and function and their ability to influence venous thrombogenesis and resolution may inspire new anticoagulant strategies that target these proteins to reduce or prevent venous thrombosis in certain at-risk patients. This article summarizes fibrinogen and factor XIII biology and current knowledge of their function during venous thromboembolism.

Utilisation of compounds from venoms in drug discovery

Difficult drug targets are becoming the normal course of business in drug discovery, sometimes due to large interacting surfaces or only small differences in selectivity regions. For these, a different approach is merited: compounds lying somewhere between the small molecule and the large antibody in terms of many properties including stability, biodistribution and pharmacokinetics. Venoms have evolved over millions of years to be complex mixtures of stable molecules derived from other somatic molecules, the stability comes from the pressure to be ready for delivery at a moment's notice. Snakes, spiders, scorpions, jellyfish, wasps, fish and even mammals have evolved independent venom systems with complex mixtures in their chemical arsenal. These venom-derived molecules have been proven to be useful tools, such as for the development of antihypotensive angiotensin converting enzyme (ACE) inhibitors and have also made successful drugs such as Byetta® (Exenatide), Integrilin® (Eptifibatide) and Echistatin. Only a small percentage of the available chemical space from venoms has been investigated so far and this is growing. In a new era of biological therapeutics, venom peptides present opportunities for larger target engagement surface with greater stability than antibodies or human peptides. There are challenges for oral absorption and target engagement, but there are venom structures that overcome these and thus provide substrate for engineering novel molecules that combine all desired properties. Venom researchers are characterising new venoms, species, and functions all the time, these provide great substrate for solving the challenges presented by today's difficult targets.

Revisiting promising preclinical intracerebral hemorrhage studies to highlight repurposable drugs for translation

Intracerebral hemorrhage is a devastating global health burden with limited treatment options and is responsible for 49% of 6.5 million annual stroke-related deaths comparable to ischemic stroke. Despite the impact of intracerebral hemorrhage, there are currently no effective treatments and so weaknesses in the translational pipeline must be addressed. There have been many preclinical studies in intracerebral hemorrhage models with positive outcomes for potential therapies in vivo, but beyond advancing the understanding of intracerebral hemorrhage pathology, there has been no translation toward successful clinical application. Multidisciplinary preclinical research, use of multiple models, and validation in human tissue are essential for effective translation. Repurposing of therapeutics for intracerebral hemorrhage may be the most promising strategy to help relieve the global health burden of intracerebral hemorrhage. Here, we have reviewed the existing literature to highlight repurposable drugs with successful outcomes in preclinical models of intracerebral hemorrhage that have realistic potential for development into the clinic for intracerebral hemorrhage.

Treatment with Delipid Extracorporeal Lipoprotein Filter from Plasma after Intravenous Thrombolysis for Acute Ischemic Stroke: A Single-Center Experience

Introduction

The delipid extracorporeal lipoprotein filter from plasma (DELP) has been approved for the treatment of acute ischemic stroke (AIS) by the China Food and Drug Administration, but its effectiveness and mechanism are not yet fully determined. The purpose of this study was to evaluate the effect of DELP treatment on AIS patients after intravenous thrombolysis.

Methods

A retrospective study was performed on AIS patients with no improvement within 24 h after intravenous thrombolysis who were subsequently treated with or without DELP. Primary outcome was the proportion with a modified Rankin scale (mRS) of 0–1 at 90 days. Secondary outcomes were changes in National Institute of Health Stroke Scale (NIHSS) score from 24 h to 14 days after thrombolysis, and the rate of improvement in stroke-associated pneumonia (SAP). The main safety outcomes were the rates of symptomatic intracranial hemorrhage and mortality. To investigate its mechanisms, serum biomarkers were measured before and after DELP.

Results

A total of 252 patients were recruited, 63 in the DELP group and 189 matched patients in the NO DELP group. Compared with the NO DELP group, the DELP group showed an increase in the proportion of mRS 0–1 at 90 days (p = 0.042). More decrease in NIHSS from 24 h to 14 days (p = 0.024), a higher rate of improvement in SAP (p = 0.022), and lower mortality (p = 0.040) were shown in DELP group. Furthermore, DELP decreased levels of interleukin (IL)-1β, E-selectin, malondialdehyde, matrix metalloprotein 9, total cholesterol, low-density lipoprotein, and fibrinogen, and increased superoxide dismutase (p< 0.05).

Conclusions

DELP following intravenous thrombolysis should be safe, and is associated with neurological function improvement, possibly through multiple neuroprotective mechanisms. Prospective trials are needed.

Anticancer potential of nanogold conjugated toxin GNP-NN-32 from Naja naja venom

Background:

Cancer is the second most common fatal disease in the world, behind cardiovascular disorders in the first place. It accounts for around 0.3 million deaths per year in India due to the lack of proper diagnostic facilities, prevention and treatment. Current therapeutic methods do not provide adequate protection and affect normal cells along with cancerous ones. Thus, there is a need for some alternative therapeutic strategy, preferably from natural products, which have been traditionally used for treatment of various diseases in the country.

Methods:

In this study, we have conjugated purified NN-32 toxin from Naja naja venom with gold nanoparticles and its anticancer potential was evaluated against human breast cancer cell lines. UV-Vis spectroscopy, dynamic light scattering, transmission electron microscopy, atomic force microscopy and zeta potential analysis were the techniques used for characterization of GNP-NN-32.

Results:

GNP-NN-32 showed dose- and time-dependent cytotoxicity against breast cancer cell lines (MCF-7 and MDA-MB-231). NN-32 and GNP-NN-32 induced apoptosis in both breast cancer cell lines. The results of CFSE cell proliferation study revealed that NN-32 and GNP-NN-32 arrested cell division in both MCF-7 and MDA-MB-231 cell lines resulting in inhibition of proliferation of these cancer cells.

Conclusion:

GNP-NN-32 showed an anticancer potential against human breast cancer cell lines. Analysis of detailed chemical characterization along with its cytotoxic property might help to perceive a new dimension of the anti-cancer potential of GNP-NN-32 that will enhance its biomedical function in near future.

Omics Technologies for Profiling Toxin Diversity and Evolution in Snake Venom: Impacts on the Discovery of Therapeutic and Diagnostic Agents

Snake venoms are primarily composed of proteins and peptides, and these toxins have developed high selectivity to their biological targets. This makes venoms interesting for exploration into protein evolution and structure-function relationships. A single venom protein superfamily can exhibit a variety of pharmacological effects; these variations in activity originate from differences in functional sites, domains, posttranslational modifications, and the formations of toxin complexes. In this review, we discuss examples of how the major venom protein superfamilies have diversified, as well as how newer technologies in the omics fields, such as genomics, transcriptomics, and proteomics, can be used to characterize both known and unknown toxins.Because toxins are bioactive molecules with a rich diversity of activities, they can be useful as therapeutic and diagnostic agents, and successful examples of toxin applications in these areas are also reviewed. With the current rapid pace of technology, snake venom research and its applications will only continue to expand.

Defibrinogen Therapy for Acute Ischemic Stroke: 1332 Consecutive Cases

This study aimed to examine the effectiveness of defibrinogen therapy on functional recovery and safety among 1332 consecutive ischemic stroke patients who had not received intravenous thrombolysis with recombinant tissue plasminogen activator. Stroke patients undergoing conservative and relatively individualized multiple-day dosing regimens of defibrinogen therapy between January 1, 2008 and May 30, 2016 were enrolled. Data were analyzed according to functional success (Barthel Index of 95 or 100, mRS of 0 or 1) and safety variables (intracranial hemorrhage, mortality and stroke recurrence). At 12 months, 18.62% (203/1087) of patients were lost to follow-up. The functional success rates were 39.84% (526/1320) and 42.23% (459/1087) as assessed by BI at 3 months and 12 months, respectively. Fifteen patients had asymptomatic intracranial hemorrhage within 24 hours after the initial defibrase administration. During the 14 days after hospitalization, 12 patients were diagnosed with symptomatic intracranial hemorrhage (sICH) and a total of 12 patients died from all causes. At 3 months, 56 patients were dead and 21 patients had recurrent stroke. The percentage of death and recurrence of stroke at 12 months were 6.81% and 3.22%, respectively. Results from the historical control showed no significant differences of functional success were detected between the patients treated with rt-PA within 6 hours of stroke onset in NINDS II and the patients treated with defibrase within 6 hours after stroke in the present study. The multiple-day dosing regimen of defibrinogen therapy using defibrase applied in the present study could achieve functional improvement among acute ischemic stroke patients, with low risks of mortality when compared with other similar studies. However, the efficacy and safety of such a defibrinogenating therapy is needed to be verified by RCTs with large sample size.

Treatment of Human Urinary Kallidinogenase Combined with Maixuekang Capsule Promotes Good Functional Outcome in Ischemic Stroke

Aims: To evaluate the clinical efficacy of Human Urinary Kallidinogenase (HUK) and Maixuekang capsule in the treatment of acute ischemic stroke (AIS) patients.

Methods: In this study, from January 2016 to July 2016, 60 patients with acute ischemic stroke were enrolled and 56 patients with complete information of whom 21 patients received HUK+ basic treatment (HUK group), 16 patients received HUK+ Maixuekang capsule + basic treatment (HUK+ Maixuekang group), 19 patients received basic treatment (control group). 0.15 PNA unit of HUK injection plus 100 ml saline in intravenous infusion was performed in the HUK group and HUK+ Maixuekang group, with once a day for 14 consecutive days. 0.75 g Maixuekang capsules were taken in HUK+ Maixuekang group, with three times a day for 14 consecutive days. The National Institutes of Health Stroke Scale (NIHSS) scores in three groups were analyzed 7 days after treatment. The modified Rankin Scale (mRS) scores in three groups were analyzed 12 month after the treatment.

Results: No difference was found in the NIHSS scores, age, gender, and comorbidities between three groups before treatment (p > 0.05). Seven days after treatment, the NIHSS scores in the HUK group and HUK+ Maixuekang group were significantly decreased than before (p _HUK = 0.001, p _{HUK+Maixuekang} < 0.001), and lower than that in the control group (p _HUK = 0.032; p _{HUK+Maixuekang} < 0.001). Twelve months after treatment, good functional outcome rate (12 month mRS score ≤ 2) in the HUK group and HUK+ Maixuekang group was significantly higher than that in the control group (p _HUK = 0.049, p _{HUK+Maixuekang} = 0.032).

Conclusion: The treatment of HUK or HUK combined with Maixuekang capsule can effectively improve the neurological function and promote long-term recovery for AIS patients.

Acute Ischaemic Stroke: Management, Recent Advances and Controversies

Acute ischaemic stroke is a major cause of death and disability. It may become an enormous burden to the patients themselves, their families as well as the health care systems. Patients at risk of airway, breathing and circulatory compromise should receive prompt resuscitation. Vital parameters and neurological status should be closely monitored. Attentions to blood pressure, temperature and sugar profile are important. The significance of early and correct diagnosis and subsequent treatment cannot be over-emphasised. There have been tremendous recent advances in different treatment modalities in acute stroke management. Various recanalisation modalities include intravenous and/or intra-arterial thrombolysis, acute defibrinogenation, anti-platelet treatment and anticoagulation. Carotid endarterectomy and endovascular strategies are recommended in selected patients. Advanced neuro-imaging techniques and neuroprotectants are being evaluated. Multidisciplinary stroke teams have been shown to improve patient survival and functional outcome. Pre-defined algorithms and protocols should be in place to expedite smooth and effective delivery of stroke service. Future directions should be aimed at exploring safer recanalisation modalities and extending the limit of the current 3-hour treatment window for thrombolysis.

Ancrod revisited: viscoelastic analyses of the effects of Calloselasma rhodostoma venom on plasma coagulation and fibrinolysis

Fibrinogen depletion via catalysis by snake venom enzymes as a therapeutic strategy to prevent or treat thrombotic disorders was utilized for over four decades, with ancrod being the quintessential agent. However, ancrod eventually was found to not be of clinical utility in large scale stroke trial, resulting in the eventual discontinuation of the administration of the drug for any indication. It was hypothesized that ancrod, possessing thrombin-like activity, may have unappreciated robust coagulation kinetics. Using thrombelastographic methods, a comparison of equivalent tissue factor initiated thrombin generation and Calloselasma rhodostoma venom (rich in ancrod activity) on plasmatic coagulation kinetics was performed. The venom resulted in thrombi that formed nearly twice as fast compared to thrombin formed clots, and there was no difference in fibrinolytic kinetics initiated by tissue-type plasminogen activator. In plasma containing iron and carbon monoxide modified fibrinogen, which may be found in patients at risk of stroke, the coagulation kinetic differences observed with venom was still more vigorous than that seen with thrombin. These phenomena may provide insight into the clinical failure of ancrod, and may serve as an impetus to revisit the concept of fibrinogen depletion via fibrinogenolytic enzymes, not those with thrombin-like activity.

Expanding the concept of neuroprotection for acute ischemic stroke: The pivotal roles of reperfusion and the collateral circulation

This review surveys the efforts taken to achieve clinically efficacious protection of the ischemic brain and underscores the necessity of expanding our purview to include the essential role of cerebral perfusion and the collateral circulation. We consider the development of quantitative strategies to measure cerebral perfusion at the regional and local levels and the application of these methods to elucidate flow-related thresholds of ischemic viability and to characterize the ischemic penumbra. We stress that the modern concept of neuroprotection must consider perfusion, the necessary substrate upon which ischemic brain survival depends. We survey the major mechanistic approaches to neuroprotection and review clinical neuroprotection trials, focusing on those phase 3 multicenter clinical trials for acute ischemic stroke that have been completed or terminated. We review the evolution of thrombolytic therapies; consider the lessons learned from the initial, negative multicenter trials of endovascular therapy; and emphasize the highly successful positive trials that have finally established a clinical role for endovascular clot removal. As these studies point to the brain's collateral circulation as key to successful reperfusion, we next review the anatomy and pathophysiology of collateral perfusion as it relates to ischemic infarction, as well as the molecular and genetic influences on collateral development. We discuss the current MR and CT-based diagnostic methods for assessing the collateral circulation and the prognostic significance of collaterals in ischemic stroke, and we consider past and possible future therapeutic directions.

New Pathways for Evaluating Potential Acute Stroke Therapies

Pharmacological therapy for acute ischemic stroke remains limited to one successful, approved treatment: tissue plasminogen activator within 3 h of stroke onset. Many neuroprotective drugs and a few other thrombolytics were evaluated in clinical trials, but none demonstrated unequivocal success and were approved by regulatory agencies. The development paradigm for such therapies needs to provide convincing evidence of efficacy and safety to obtain approval by the Food and Drug Administration (FDA). The FDA modernization act of 1997 stated that such evidence could be derived from one large phase III trial with a clinical endpoint and supportive evidence. Drugs being developed for acute ischemic stroke can potentially be approved under this act by coupling a major phase III trial with supportive evidence provided by a phase IIB trial demonstrating an effect on a relevant biomarker such as magnetic resonance imaging or computed tomography assessment of ischemic lesion growth. Statistical approaches have been developed to optimize the design of such an imaging-based phase IIB study, for example approaches that modify randomization probabilities to assign larger proportions of patients to the ‘winning’ strategy (i.e. ‘pick the winner’ strategies) with an interim assessment to reduce the sample size requirement. Demonstrating a treatment effect on a relevant imaging-based biomarker should provide supportive evidence for a new drug application, if a subsequent phase III trial with a clinical outcome demonstrates a significant treatment effect.

Coronary Risk Stratification in Patients with Ischemic Stroke or Transient Ischemic Stroke Attack

Background

The risk of coronary artery disease (CAD) is traditionally considered high in patients who had an ischemic stroke or a transient ischemic attack (TIA). However, few studies have specifically assessed the absolute risk of coronary events in those patients and predictors of such events are not well known.

Summary of review

The overall risks of myocardial infarction and nonstroke vascular death are each around 2% per year. However, those risks are only about 1% per year in patients without CAD (i.e. the only ones who are likely to benefit from specific additional strategies). The prevalence of asymptomatic CAD ranges from 15% to 60%. Although potentially higher, the risk of CAD in patients with stroke/TIA related to atherosclerosis also seems to vary widely depending on the extent of the disease. Given the relatively low CAD risk, a simple systematic reinforcement of medical treatment in all patients may be not relevant. Up to now, there have been only limited ways to stratify the CAD risk in stroke/TIA patients. High-risk patients may be identified using the traditional cardiac scoring systems, but their validity has never been specifically assessed in stroke populations. The relative influence of traditional risk factors may be altered after a first vascular event. Stroke patients could also be screened for asymptomatic CAD. However, there is no simple and valid screening test for asymptomatic CAD that could be applied to all patients. Finally, there is still uncertainty about the potential benefits of treating asymptomatic CAD. Therefore, should the identification of patients with asymptomatic CAD requiring revascularization become feasible, the relevance of this strategy would remain to be evaluated by a randomized clinical trial.

Conclusion

The absolute risk of CAD in stroke/TIA patients is moderately high. More research is needed to identify high risk patients who could benefit from specific strategies.

Neurovascular dysfunction and neurodegeneration in dementia and Alzheimer's disease

Vascular insults can initiate a cascade of molecular events leading to neurodegeneration, cognitive impairment, and dementia. Here, we review the cellular and molecular mechanisms in cerebral blood vessels and the pathophysiological events leading to cerebral blood flow dysregulation and disruption of the neurovascular unit and the blood-brain barrier, which all may contribute to the onset and progression of dementia and Alzheimer's disease (AD). Particularly, we examine the link between neurovascular dysfunction and neurodegeneration including the effects of AD genetic risk factors on cerebrovascular functions and clearance of Alzheimer's amyloid-β peptide toxin, and the impact of vascular risk factors, environment, and lifestyle on cerebral blood vessels, which in turn may affect synaptic, neuronal, and cognitive functions. Finally, we examine potential experimental treatments for dementia and AD based on the neurovascular model, and discuss some critical questions to be addressed by future studies. This article is part of a Special Issue entitled: Vascular Contributions to Cognitive Impairment and Dementia edited by M. Paul Murphy, Roderick A. Corriveau and Donna M. Wilcock.

Changing Management of Acute Ischaemic Stroke: the New Treatments and Emerging Role of Endovascular Therapy

OPINION STATEMENT

Urgent reperfusion of the ischaemic brain is the aim of stroke treatment, and the last two decades have seen a rapid advancement in the medical and endovascular treatment of acute ischaemic stroke. Intravenous tissue plasminogen activator (tPA) was first introduced as a safe and effective thrombolytic agent followed by the introduction of newer thrombolytic agents as well as anticoagulant and antiplatelet agents, proposed as potentially safer drugs with more favourable interaction profiles. In addition to chemo-thrombolysis, other techniques including transcranial sonothrombolysis and microbubble cavitation have been introduced which are showing promising results, but await large-scale clinical trials. These developments in medical therapies which are undoubtedly of great importance due to their potential widespread and immediate availability are paralleled with gradual but steady improvements in endovascular recanalisation techniques which were initiated by the introduction of the MERCI (Mechanical Embolus Removal in Cerebral Ischemia) and Penumbra systems. The introduction of the Solitaire device was a significant achievement in reliable and safe endovascular recanalisation and was followed by further innovative stent retrievers. Initial trials failed to show a solid benefit in endovascular intervention compared with IV-tPA alone. These counterintuitive results did not last long, however, when a series of very well-designed randomised controlled trials, pioneered by MR-CLEAN, EXTEND-IA and ESCAPE, emerged, confirming the well-believed daily anecdotal evidence. There have now been seven positive trials of endovascular treatment for acute ischaemic stroke. Now that level I evidence regarding the superiority of endovascular recanalisation is abundantly available, the clinical challenge is how to select patients suitable for intervention and to familiarise and educate stroke care providers with this recent development in stroke care. It is important for the interventional services to be provided only in comprehensive stroke centres and endovascular interventions attempted by experienced well-trained operators, at this stage as an adjunct to the established medical treatment of IV-tPA, if there are no contraindications.

[Intravenous thrombolysis in ischemic stroke: Therapeutic perspectives]

New therapeutic strategies are under evaluation to improve the treatment of acute ischemic stroke (AIS). Approaches combining intravenous (IV) thrombolysis with recombinant tissue plasminogen activator (rt-PA) and antithrombotic agents are currently evaluated. The combination of IV rt-PA and aspirin showed a high rate of intracranial hemorrhage whereas the association of rt-PA and eptifibatide seems more promising. The results of recent studies evaluating the administration of eptifibatide or argatroban in conjunction with conventional IV thrombolysis with rt-PA are expected to clarify the safety and efficacy of these treatments. More fibrin-specific plasminogen activators, tenecteplase and desmoteplase, are also investigated. These fibrinolytic agents showed a favorable safety profile but their efficacy in AIS remains uncertain. While phase III studies, DIAS-3 and DIAS-4, evaluating IV desmoteplase up to nine hours after stroke onset did not meet the primary endpoint, the results of studies comparing IV tenecteplase and IV rt-PA are expected.

Alteplase Reduces Downstream Microvascular Thrombosis and Improves the Benefit of Large Artery Recanalization in Stroke

BACKGROUND AND PURPOSE

Downstream microvascular thrombosis (DMT) is known to be a contributing factor to incomplete reperfusion in acute ischemic stroke. The aim of this study was to determine the timing of DMT with intravital imaging and to test the hypothesis that intravenous alteplase infusion could reduce DMT in a transient middle cerebral artery occlusion (MCAO) rat stroke model.

METHODS

Rats were subjected to 60-minute transient MCAO. Alteplase (10 mg/kg) was administered 30 minutes after the beginning of MCAO. Real-time intravital fluorescence microscopy through a dura-sparing craniotomy was used to visualize circulating blood cells and fibrinogen. Cerebral microvessel patency was quantitatively evaluated by fluorescein isothiocyanate-dextran perfusion.

RESULTS

Immediately after MCAO, platelet and leukocyte accumulation were observed mostly in the venous compartment. Within 30 minutes after MCAO, microthrombi and parietal fibrin deposits were detected in postcapillary microvessels. Alteplase treatment significantly (P=0.006) reduced infarct volume and increased the percentage of perfused vessels during MCAO (P=0.02) compared with saline. Plasma levels of fibrinogen from alteplase-treated rats showed a rapid and profound hypofibrinogenemia. In vitro platelet aggregation demonstrated that alteplase reduced platelet aggregation (P=0.0001) and facilitated platelet disaggregation (P=0.001). These effects were reversible in the presence of exogenous fibrinogen.

CONCLUSIONS

Our data demonstrate that DMT is an early phenomenon initiated before recanalization. We further show that alteplase-dependent maintenance of downstream perfusion during MCAO improves acute ischemic stroke outcome through a fibrinogen-dependent platelet aggregation reduction. Our results indicate that early targeting of DMT represents a therapeutic strategy to improve the benefit of large artery recanalization in acute ischemic stroke.

Advances in medical revascularisation treatments in acute ischemic stroke

Urgent reperfusion of the ischaemic brain is the aim of stroke treatment and there has been ongoing research to find a drug that can promote vessel recanalisation more completely and with less side effects. In this review article, the major studies which have validated the use and safety of tPA are discussed. The safety and efficacy of other thrombolytic and anticoagulative agents such as tenecteplase, desmoteplase, ancrod, tirofiban, abciximab, eptifibatide, and argatroban are also reviewed. Tenecteplase and desmoteplase are both plasminogen activators with higher fibrin affinity and longer half-life compared to alteplase. They have shown greater reperfusion rates and improved functional outcomes in preliminary studies. Argatroban is a direct thrombin inhibitor used as an adjunct to intravenous tPA and showed higher rates of complete recanalisation in the ARTTS study with further studies which are now ongoing. Adjuvant thrombolysis techniques using transcranial ultrasound are also being investigated and have shown higher rates of complete recanalisation, for example, in the CLOTBUST study. Overall, development in medical therapies for stroke is important due to the ease of administration compared to endovascular treatments, and the new treatments such as tenecteplase, desmoteplase, and adjuvant sonothrombolysis are showing promising results and await further large-scale clinical trials.

Reperfusion therapies of acute ischemic stroke: potentials and failures

Over the past 20 years, clinical research has focused on the development of reperfusion therapies for acute ischemic stroke (AIS), which include the use of systemic intravenous thrombolytics (alteplase, desmoteplase, or tenecteplase), the augmentation of systemic intravenous recanalization with ultrasound, the bridging of intravenous with intra-arterial thrombolysis, the use of multi-modal approaches to reperfusion including thrombectomy and thromboaspiration with different available retrievers. Clinical trials testing these acute reperfusion therapies provided novel insight regarding the comparative safety and efficacy, but also raised new questions and further uncertainty on the field. Intravenous alteplase (tPA) remains the fastest and easiest way to initiate acute stroke reperfusion treatment, and should continue to be the first-line treatment for patients with AIS within 4.5 h from onset. The use of tenecteplase instead of tPA and the augmentation of systemic thrombolysis with ultrasound are both novel therapeutical modalities that may emerge as significant options in AIS treatment. Endovascular treatments for AIS are rapidly evolving due to technological advances in catheter-based interventions and are currently emphasizing speed in order to result in timely restoration of perfusion of still-salvageable, infarcted brain tissue, since delayed recanalization of proximal intracranial occlusions has not been associated with improved clinical outcomes. Comprehensive imaging protocols in AIS may enable better patient selection for endovascular interventions and for testing multi-modal combinatory strategies.

Pharmacological and genetic depletion of fibrinogen protects from kidney fibrosis

Fibrinogen (Fg) has been implicated in the pathogenesis of several fibrotic disorders by acting as a profibrotic ligand for a variety of cellular surface receptors and by modulating the provisional fibrin matrix formed after injury. We demonstrated increased renal Fg expression after unilateral ureteral obstruction and folic acid (FA) nephropathy in mice, respectively. Urinary Fg excretion was also increased in FA nephropathy. Using in vitro and in vivo approaches, our results suggested that IL-6 mediates STAT3 activation in kidney fibrosis and that phosphorylated (p)STAT3 binds to Fgα, Fgβ, and Fgγ promoters in the kidney to regulate their transcription. Genetically modified Fg heterozygous mice (∼75% of normal plasma Fg levels) exhibited only 3% kidney interstitial fibrosis and tubular atrophy after FA nephropathy compared with 24% for wild-type mice. Fibrinogenolysis through Ancrod administration after FA reduced interstitial fibrosis more than threefold compared with vehicle-treated control mice. Mechanistically, we show that Fg acts synergistically with transforming growth factor (TGF)-β1 to induce fibroblast proliferation and activates TGF-β1/pSMAD2 signaling. This study offers increased understanding of Fg expression and molecular interactions with TGF-β1 in the progression to kidney fibrosis and, importantly, indicates that fibrinogenolytics like Ancrod present a treatment opportunity for a yet intractable disease.

Mapping individual brains to guide restorative therapy after stroke: Rationale and pilot studies

Some treatments under development to improve motor outcome after stroke require information about organization of individual subject's brain. The current study aimed to characterize normal inter-subject differences in localization of motor functions, and to consider these findings in relation to a potential treatment of motor deficits after stroke. Functional MRI (fMRI) scanning in 14 subjects examined right index finger tapping, shoulder rotation, or facial movement. The largest activation cluster in left sensorimotor cortex was identified for each task, and its center expressed in Talairach stereotaxic coordinates. Across subjects, each task showed considerable variability in activation site coordinates. For example, during finger tapping, the range for center of activation was 7 mm in the x-axis, 19 mm in the y-axis, and 11 mm in the z-axis. The mean value for center of activation was significantly different for all three coordinates for all pairwise task comparisons. However, the distribution of activation site centers for the finger task overlapped with the other two tasks in the x- and y-axes, and with the shoulder task in the z-axis. On average, the center of activation for the three motor tasks were spatially separated and somatotopically distributed. However, across the population, there was considerable overlap in the center of activation site, especially for finger and shoulder movements. Restorative therapies that aim to target specific body segments, such as the hand, in the post-stroke motor system may need to map the individual brain rather than rely on population averages. Initial details are presented of a study using this approach to evaluate such a therapy.

Management of acute ischemic stroke

Stroke is one of the most common causes of morbidity and mortality in hospitalized patients in the United States. A proper understanding of stroke mechanisms helps to guide specific case management. The only therapy approved by the US Food and Drug Administration for the management of acute ischemic stroke is initiation of intravenous recombinant tissue plasminogen activator within 3 hours of symptom onset. Other treatment options include intra-arterial recombinant tissue plasminogen activator, mechanical thrombectomy, clot retrieval, or a combination of these approaches. In this article, we provide an evidence-based review of the diagnostic approach for acute ischemic stroke, including recognizing common stroke mimics. We detail the initial medical management of acute stroke and the medical and surgical therapeutic interventions for patients who have sustained acute ischemic stroke.

The quest for arterial recanalization in acute ischemic stroke-the past, present and the future

Ischemic stroke is one of the major causes of mortality and long-term disability. In the recent past, only very few treatment options were available and a considerable proportion of stroke survivors remained permanently disabled. However, over the last 2 decades rapid advances in acute stroke care have resulted in a corresponding improvement in mortality rates and functional outcomes. In this review, we describe the evolution of systemic thrombolytic agents and various interventional devices, their current status as well as some of the future prospects. We reviewed literature pertaining to acute ischemic stroke reperfusion treatment. We explored the current accepted treatment strategies to attain cerebral reperfusion via intravenous modalities and compare and contrast them within the boundaries of their clinical trials. Subsequently we reviewed the trials for interventional devices for acute ischemic stroke, categorizing them into thrombectomy devices, aspiration devices, clot disruption devices and thrombus entrapment devices. Finally we surveyed several of the alternative reperfusion strategies available. We also shed some light on the controversies surrounding the current strategies of treatment of acute ischemic stroke. Acute invasive interventional strategies continue to improve along with the noninvasive modalities. Both approaches appear promising. We conducted a comprehensive chronological review of the existing treatments as well as upcoming remedies for acute ischemic stroke.

Plasminogen activators and ischemic stroke: conditions for acute delivery

Appropriate acute treatment with plasminogen activators (PAs) can significantly increase the probability of minimal or no disability in selected ischemic stroke patients. There is a great deal of evidence showing that intravenous recombinant tissue PAs (rt-PA) infusion accomplishes this goal, recanalization with other PAs has also been demonstrated in the development of this treatment. Recanalization of symptomatic, documented carotid or vertebrobasilar arterial territory occlusions have also been achieved by local intra-arterial PA delivery, although only a single prospective double-blinded randomized placebo-controlled study has been reported. The increase in intracerebral hemorrhage with these agents by either delivery approach underscores the need for careful patient selection, dose-appropriate safety and efficacy, proper clinical trial design, and an understanding of the evolution of cerebral tissue injury due to focal ischemia. Principles underlying the evolution of focal ischemia have been expanded by experience with acute PA intervention. Several questions remain open that concern the manner in which PAs can be applied acutely in ischemic stroke and how injury development can be limited.

Coagulant thrombin-like enzyme (barnettobin) from Bothrops barnetti venom: molecular sequence analysis of its cDNA and biochemical properties

The thrombin-like enzyme from Bothrops barnetti named barnettobin was purified. We report some biochemical features of barnettobin including the complete amino acid sequence that was deduced from the cDNA. Snake venom serine proteases affect several steps of human hemostasis ranging from the blood coagulation cascade to platelet function. Barnettobin is a monomeric glycoprotein of 52 kDa as shown by reducing SDS-PAGE, and contains approx. 52% carbohydrate by mass which could be removed by N-glycosidase. The complete amino acid sequence was deduced from the cDNA sequence. Its sequence contains a single chain of 233 amino acid including three N-glycosylation sites. The sequence exhibits significant homology with those of mammalian serine proteases e.g. thrombin and with homologous TLEs. Its specific coagulant activity was 251.7 NIH thrombin units/mg, releasing fibrinopeptide A from human fibrinogen and showed defibrinogenating effect in mouse. Both coagulant and amidolytic activities were inhibited by PMSF. N-deglycosylation impaired its temperature and pH stability. Its cDNA sequence with 750 bp encodes a protein of 233 residues. Indications that carbohydrate moieties may play a role in the interaction with substrates are presented. Barnettobin is a new defibrinogenating agent which may provide an opportunity for the development of new types of anti-thrombotic drugs.

Drug treatment of acute ischemic stroke

Acute ischemic stroke (AIS) is the fourth leading cause of death and the leading cause of adult disability in the USA. AIS most commonly occurs when a blood vessel is obstructed leading to irreversible brain injury and subsequent focal neurologic deficits. Drug treatment of AIS involves intravenous thrombolysis with alteplase (recombinant tissue plasminogen activator [rtPA]). Intravenous alteplase promotes thrombolysis by hydrolyzing plasminogen to form the proteolytic enzyme plasmin. Plasmin targets the blood clot with limited systemic thrombolytic effects. Alteplase must be administered within a short time window to appropriate patients to optimize its therapeutic efficacy. Recent trials have shown this time window may be extended from 3 to 4.5 hours in select patients. Other acute supportive interventions for AIS include maintaining normoglycemia, euthermia and treating severe hypertension. Urgent anticoagulation for AIS has generally not shown benefits that exceed the hemorrhage risks in the acute setting. Urgent antiplatelet use for AIS has limited benefits and should only promptly be initiated if alteplase was not administered, or after 24 hours if alteplase was administered. The majority of AIS patients do not receive thrombolytic therapy due to late arrival to emergency departments and currently there is a paucity of acute interventions for them. Ongoing clinical trials may lead to further medical breakthroughs to limit the damage inflicted by this devastating disease.

Guidelines for the early management of patients with acute ischemic stroke: a guideline for healthcare professionals from the American Heart Association/American Stroke Association

BACKGROUND AND PURPOSE

The authors present an overview of the current evidence and management recommendations for evaluation and treatment of adults with acute ischemic stroke. The intended audiences are prehospital care providers, physicians, allied health professionals, and hospital administrators responsible for the care of acute ischemic stroke patients within the first 48 hours from stroke onset. These guidelines supersede the prior 2007 guidelines and 2009 updates.

METHODS

Members of the writing committee were appointed by the American Stroke Association Stroke Council's Scientific Statement Oversight Committee, representing various areas of medical expertise. Strict adherence to the American Heart Association conflict of interest policy was maintained throughout the consensus process. Panel members were assigned topics relevant to their areas of expertise, reviewed the stroke literature with emphasis on publications since the prior guidelines, and drafted recommendations in accordance with the American Heart Association Stroke Council's Level of Evidence grading algorithm.

RESULTS

The goal of these guidelines is to limit the morbidity and mortality associated with stroke. The guidelines support the overarching concept of stroke systems of care and detail aspects of stroke care from patient recognition; emergency medical services activation, transport, and triage; through the initial hours in the emergency department and stroke unit. The guideline discusses early stroke evaluation and general medical care, as well as ischemic stroke, specific interventions such as reperfusion strategies, and general physiological optimization for cerebral resuscitation.

CONCLUSIONS

Because many of the recommendations are based on limited data, additional research on treatment of acute ischemic stroke remains urgently needed.

Biochemistry of envenomation

Venoms and toxins are of significant interest due to their ability to cause a wide range of pathophysiological conditions that can potentially result in death. Despite their wide distribution among plants and animals, the biochemical pathways associated with these pathogenic agents remain largely unexplored. Impoverished and underdeveloped regions appear especially susceptible to increased incidence and severity due to poor socioeconomic conditions and lack of appropriate medical treatment infrastructure. To facilitate better management and treatment of envenomation victims, it is essential that the biochemical mechanisms of their action be elucidated. This review aims to characterize downstream envenomation mechanisms by addressing the major neuro-, cardio-, and hemotoxins as well as ion-channel toxins. Because of their use in folk and traditional medicine, the biochemistry behind venom therapy and possible implications on conventional medicine will also be addressed.

Fibrinogen depleting agents for acute ischaemic stroke

BACKGROUND

Fibrinogen depleting agents reduce fibrinogen in blood plasma, reduce blood viscosity and hence increase blood flow. This may help remove the blood clot blocking the artery and re-establish blood flow to the affected area of the brain after an ischaemic stroke. The risk of haemorrhage may be less than with thrombolytic agents. This is an update of a Cochrane review first published in 1997 and last updated in 2003.

OBJECTIVES

To assess the effect of fibrinogen depleting agents in patients with acute ischaemic stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (July 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 7), the Chinese Stroke Trials Register (September 2011), MEDLINE (1950 to July 2011), EMBASE (1980 to July 2011) and Web of Science Conference Proceedings (1990 to July 2011). In addition, we searched six Chinese databases, four ongoing trials registers (July 2011) and relevant reference lists. For previous versions of the review, we handsearched journals and contacted researchers in China and Japan and relevant drug companies.

SELECTION CRITERIA

Randomised trials of fibrinogen depleting agents started within 14 days of stroke onset, compared with control in patients with definite or possible ischaemic stroke.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed trial quality and extracted the data. We resolved disagreement by discussion.

MAIN RESULTS

We included eight trials involving 5701 patients. Six trials tested ancrod and two trials tested defibrase (patients were treated for less than three hours to less than 48 hours). Allocation concealment was adequate in seven trials. Fibrinogen depleting agents marginally reduced the proportion of patients who were dead or disabled at the end of follow-up (risk ratio (RR) 0.95, 95% confidence Interval (CI) 0.90 to 0.99, 2P = 0.02). There was no statistically significant difference in death from all causes during the scheduled treatment or follow-up period. There were fewer stroke recurrences in the treatment group than in the control group (RR 0.67, 95% CI 0.49 to 0.92, 2P = 0.01). However, symptomatic intracranial haemorrhage was about twice as common in the treatment group compared with the control group (RR 2.42, 95% CI 1.65 to 3.56, 2P < 0.00001).

AUTHORS' CONCLUSIONS

The current evidence is promising but not yet sufficiently robust to support the routine use of fibrinogen depleting agents for the treatment of acute ischaemic stroke. Further trials are needed to determine whether there is worthwhile benefit, and if so, which categories of patients are most likely to benefit.

Adjunctive and alternative approaches to current reperfusion therapy

BACKGROUND AND PURPOSE

Current ischemic stroke reperfusion therapy consists of intravenous thrombolysis given in eligible patients after review of a noncontrast CT scan and a time-based window of opportunity. Rapid clot lysis has a strong association with clinical improvement but remains incomplete in many patients. This review appraises novel adjunctive or alternative approaches to current reperfusion strategies being tested in all trial phases. Summary of Review- Alternative approaches to current reperfusion therapy can be separated into 4 main categories: (1) combinatory approaches with other drugs or devices; (2) novel systemic thrombolytic agents; (3) endovascular medical or mechanical reperfusion treatments; and (4) noninvasive or minimally invasive methods to augment cerebral blood flow and alleviate intracranial blood flow steal.

CONCLUSIONS

Reperfusion treatments must be provided as fast as possible in patients most likely to benefit. Patients who fail to rapidly reperfuse may benefit from other strategies that maintain collateral flow or protect tissue at risk.

Guidelines for the treatment of acute ischaemic stroke

INTRODUCTION

Update of Acute Ischaemic Stroke Treatment Guidelines of the Spanish Neurological Society based on a critical review of the literature. Recommendations are made based on levels of evidence from published data and studies.

DEVELOPMENT

Organized systems of care should be implemented to ensure access to the optimal management of all acute stroke patients in stroke units. Standard of care should include treatment of blood pressure (should only be treated if values are over 185/105 mmHg), treatment of hyperglycaemia over 155 mg/dl, and treatment of body temperature with antipyretic drugs if it rises above 37.5 °C. Neurological and systemic complications must be prevented and promptly treated. Decompressive hemicraniectomy should be considered in cases of malignant cerebral oedema. Intravenous thrombolysis with rtPA should be administered within 4.5 hours from symptom onset, except when there are contraindications. Intra-arterial pharmacological thrombolysis can be considered within 6 hours, and mechanical thrombectomy within 8 hours from onset, for anterior circulation strokes, while a wider window of opportunity up to 12-24 hours is feasible for posterior strokes. There is not enough evidence to recommend routine use of the so called neuroprotective drugs. Anticoagulation should be administered to patients with cerebral vein thrombosis. Rehabilitation should be started as early as possible.

CONCLUSION

Treatment of acute ischaemic stroke includes management of patients in stroke units. Systemic thrombolysis should be considered within 4.5 hours from symptom onset. Intra-arterial approaches with a wider window of opportunity can be an option in certain cases. Protective and restorative therapies are being investigated.

Linking inflammation and coagulation: novel drug targets to treat organ ischemia

PURPOSE OF REVIEW

Activation of the coagulation system during ischemia/reperfusion injury is an unavoidable event and even further augmented during cardiovascular surgery. Clotting not only leads to disturbance of blood rheology but also enhances the inflammatory response. We aim to highlight the inflammatory properties of the coagulation system and novel potential therapeutic approaches targeting both features.

RECENT FINDINGS

Heparin, a thrombin inhibitor, is still the drug of choice for preventing coagulation following, for example, cardiovascular surgery. On the contrary, much effort is done to evaluate the utilization of direct thrombin inhibitors to prevent ischemia/reperfusion injury. Furthermore, targeting the inflammatory potential of the coagulation system seems to be very promising. Fibrin(ogen) and its degradation products modulate the inflammatory response, especially by inducing leukocyte migration. Inhibiting these pro-inflammatory effects, for example, by administration of Bβ15-42 was recently shown to be beneficial under various inflammatory conditions.

SUMMARY

Ischemia and reperfusion are common activators of coagulation that is also accompanied by inflammation. Therefore, targeting this well orchestrated system might be of therapeutic benefit, as its mode of action is dual: clotting inhibition and anti-inflammation. This novel therapeutic approach might at least be of benefit in the treatment of systemic inflammatory syndromes following, that is, cardiovascular surgery.

Ancrod and fibrin formation: perspectives on mechanisms of action

BACKGROUND AND PURPOSE

Ancrod, derived from Malayan pit viper venom, has been tested as ischemic stroke treatment in clinical trials with inconsistent results. We studied the actions of ancrod on fibrinolysis pathways in patient plasma samples and endothelial cell culture systems.

METHODS

We analyzed fibrinogen levels during the first 6 hours of ancrod infusion in patients entered in the Stroke Treatment with Ancrod Trial. For the in vitro study, human brain microvascular endothelial cells incubated with plasminogen or with human brain microvascular endothelial cell-conditioned medium were co-incubated with ancrod and fibrinogen under normal or oxygen-glucose deprivation conditions over 6 hours.

RESULTS

Fibrinogen levels decreased both in vivo and in vitro. Ancrod generated fibrinopeptide A, caused visible clot formation, and reduced levels of tissue-type plasminogen activator antigen in the human brain microvascular endothelial cell system and in a cell-free system with conditioned media.

CONCLUSIONS

The in vitro results indicate that ancrod causes local fibrin formation and secondary depletion of tissue-type plasminogen activator by binding to fibrin clot. Ancrod-induced fibrin formation could result in cerebral microvascular occlusion and may explain the suboptimal clinical effects of ancrod in human stroke trials.

Fibrinolysis and Beyond: Bridging the Gap between Local and Systemic Clot Removal

Recanalization methods in ischemic stroke have been progressively expanded over the past years. In addition the continuous development of specialized mechanical devices for thrombectomy a broad spectrum of new drugs has been tested: Both options, novel drugs as well as new devices, can be employed independently of each other, but in most cases a combination of the two with the standard treatment of intravenous fibrinolysis is applied. Until recently, a large number of case series have been performed to investigate the effects of various drugs and interventions, but only a few trials have been conducted to determine the optimal conditions for combining both procedures. This review surveys the different systemic and endovascular vessel reopening practices and their major bridging techniques.

Thermal detoxification of the venom from Daboia russelli russelli of Eastern India with restoration of fibrinolytic activity

The fibrinolytic components of venom have been evaluated for long in the enzymatic treatment of thrombosis. Russell's viper venom has fibrinolytic activity that is associated with hemorrhagic activity. Here it has been investigated whether the crude venom could be detoxified by thermal denaturation retaining fibrinolytic activity. The venom at 0.05 mg/ml in 20 mM K-phosphate, pH 7.5 when exposed to 100 °C for 5 min followed by cooling at 25 °C for 1 h led to its detoxification, while 80-85% of the fibrinolytic activity was recovered. Assessment of toxicity of the renatured venom in mice after injection at 5 fold excess of the lethal dose showed no lethality including hemorrhage, myotoxicity, cytotoxicity and liver toxicity. This simple method for preparation of fibrinolytic component for therapeutic use may be developed.

Incidence of subclinical coronary atherosclerosis in patients with suspected embolic stroke using cardiac computed tomography

The purpose of this study was to investigate the incidence of subclinical coronary artery disease (CAD) in patients with suspected acute embolic stroke or transient ischemic attack (TIA) using 64-row multi-slice computed tomography (MSCT) and to examine its association with conventional risk stratification. We consecutively enrolled 175 patients (66 ± 13 years, 50% men) suspected to have had embolic stroke/TIA clinically or radiologically, and underwent 64-row MSCT to evaluate for a possible cardiac source of embolism. Both coronary artery calcium scoring (CACS) and coronary CT angiography (CCTA) were concurrently performed based on standard scanning protocols. Patients with a history of angina or documented CAD, and those with significant carotid stenosis were excluded. Atherosclerotic plaques were indentified in 105 (60%) individuals; 37 (21%) had occult CAD of ≥50% diameter stenosis on CCTA. Subjects with and without ≥50% occult CAD on CCTA had similar prevalence of cardiovascular risk factors. Thirty out of 175 (17%) individuals with ≥50% occult CAD would have missed further cardiac testing based on the American Heart association and the American Stroke Association guideline. However, these numbers would be reduced to 2% (4/175) using CACS. In logistic regression analysis, only CACS independently predicted the presence ≥50% occult CAD evidenced by CCTA. Subclinical CAD, including ≥50% stenotic disease, is highly prevalent in patients who had suffered a suspected embolic stroke. The current guideline for further cardiac testing may have limited value to identify patients with ≥50% CAD in this patient population, which can be improved by adopting CACS.

Hyperacute therapies for childhood stroke: a case report and review of the literature

Objective. The optimal management of pediatric patients with arterial ischemic stroke (AIS) is not known. Despite this, goal-oriented, time-sensitive therapies geared to rapid reestablishment of arterial blood flow are occasionally applied with beneficial effects. The inconsistent approach to AIS is in part due to a lack of knowledge and preparedness. Methods. Case report of a 12-year-old male with right middle cerebral artery (MCA) occlusion resulting in dense left hemiplegia and mutism and review of the literature. Intervention(s). Mechanical thrombectomy, intra-arterial administration of rt-PA, vasodilators, and platelet inhibitors, and systemic anticoagulation and subsequent critical care support. Results. Restoration of right MCA blood flow and complete resolution of neurologic deficits. Conclusion. We report the gratifying outcome of treatment of a case of AIS in a pediatric patient treated with hyperacute therapies geared to arterial recanalization and subsequent neurologic critical care and review the pertinent literature. Guidelines for the emergency room management of pediatric AIS from prospective, randomized trials are needed.