Clinical diagnosis of TIA or minor stroke and prognosis in patients with neurological symptoms: A rapid access clinic cohort

Transient ischemic attack and minor stroke as "surgeons affairs": a narrative review

OBJECTIVE

The scope of this paper is to review the subtypes of transient ischemic attack (TIA) and minor stroke (mS) in which a surgical treatment is needed, discussing the importance and the timing of a multidisciplinary approach, in order to achieve an optimized management and prevent major strokes or other critical complications.

MATERIALS AND METHODS

The keywords "transient ischemic attack," "minor stroke," "surgical treatment," "vascular surgery," "heart surgery," "neurosurgery," and "multidisciplinary" were searched using MEDLINE, EMBASE, and Scopus. Relevant search results were discussed by the authors for references inclusion.

RESULTS

Notwithstanding that best medical therapy is usually the first choice for the most part of cases, there are specific but recurrent etiologies that must be properly recognized because of a potential surgical approach, even in urgency. In fact, symptomatic carotid stenosis, or particular cases of hemodynamic cerebrovascular events, should be promptly referred to vascular surgeon, since increasing evidences highlighted a benefit from an early artery revascularization. In addition, beyond arrhythmic causes, cardioembolic events due to bacterial endocarditis and atrial myxoma should be quickly diagnosed, possibly in emergency department, because they are a presumptive urgency for heart surgery. In addition to the above-mentioned conditions, in patients suffering from vertebrobasilar TIA or mS, clinicians should keep in mind the Bow Hunter disease, because surgical artery decompression can represent the only suitable treatment in selected cases.

CONCLUSIONS

TIA and mS require a multidisciplinary in order to discuss therapeutic options, comparing risks and benefits and determining the best timing for an optimized management.

Transient Ischemic Attack Outpatient Clinic: Past Journey and Future Adventure

A transient ischemic attack (TIA), a constellation of temporary neurological symptoms, precedes stroke in one-fifth of patients. Thus far, many clinical models have been introduced to optimize the quality, time to treatment, and cost of acute TIA care, either in an inpatient or outpatient setting. In this article, we aim to review the characteristics and outcomes of outpatient TIA clinics across the globe. In addition, we discussed the main challenges for outpatient management of TIA, including triage and diagnosis, and the system dynamics of the clinics. We further reviewed the potential developments in TIA care, such as telemedicine, predictive analytics, personalized medicine, and advanced imaging.

Clinical Diagnosis and Magnetic Resonance Imaging in Patients With Transient and Minor Neurological Symptoms: A Prospective Cohort Study

BACKGROUND

The utility of magnetic resonance imaging (MRI) brain in patients with transient or minor neurological symptoms is uncertain. We sought to determine the proportion of participants with transient or minor neurological symptoms who had MRI evidence of acute ischemia at different clinical probabilities of transient ischemic attack (TIA) or minor stroke.

METHODS

Cohort of participants with transient or minor neurological symptoms from emergency and outpatient settings. Clinicians at different levels of training gave each participant a diagnostic probability (probable when TIA/stroke was the most likely differential diagnosis; possible when TIA/stroke was not the most likely differential diagnosis; or uncertain when diagnostic probability could not be given) before 1.5 or 3T brain MRI ≤5 days from onset. Post hoc, each clinical syndrome was defined blind to MRI findings as National Institute of Neurological Disorders and Stroke criteria TIA/stroke; International Headache Society criteria migraine aura; non-TIA focal symptoms; or nonfocal symptoms. MRI evidence of acute ischemia was defined by 2 reads of MRI. Stroke was ascertained for at least 90 days and up to 18 months after recruitment.

RESULTS

Two hundred seventy-two participated (47% female, mean age 60, SD 14), 58% with MRI ≤2 days of onset. Most (92%) reported focal symptoms. MR evidence of acute ischemia was found, for stroke/TIA clinical probabilities of probable 23 out of 75 (31% [95% CI, 21%-42%]); possible 26 out of 151 (17% [12%-24%]); and uncertain 9 out of 43, (20% [10%-36%]). MRI evidence of acute ischemia was found in National Institute of Neurological Disorders and Stroke criteria TIA/stroke 40 out of 95 (42% [32%-53%]); migraine aura 4 out of 38 (11% [3%-25%]); non-TIA focal symptoms 16 out of 99 (16% [10%-25%]); and no focal features 1 out of 29 (3% [0%-18%]). After MRI, a further 14 (5% [95% CI, 3-8]) would be treated with an antiplatelet drug compared with treatment plan before MRI. By 18 months, a new ischemic stroke occurred in 9 out of 61 (18%) patients with MRI evidence of acute ischemia and 2 out of 211 (1%) without (age-adjusted hazard ratio, 13 [95% CI, 3-62]; P<0.0001).

CONCLUSIONS

MRI evidence of acute brain ischemia was found in about 1 in 6 transient or minor neurological symptoms patients with a nonstroke/TIA initial diagnosis or uncertain diagnosis. Methods to determine the clinical and cost-effectiveness of MRI are needed in this population.

Dexmedetomidine exerts its protective effect on cerebral ischemia reperfusion injury in mice by inhibiting ferroptosis

OBJECTIVES

Stroke is one of the major diseases that can threaten human life and health. The incidence of ischemic stroke accounts for more than 70% of stroke. The mechanism of ischemia reperfusion (IR) injury caused by ischemic stroke is extremely complex. In recent years, dexmedetomidine has been increasingly studied in anti-cerebral IR injury as a common clinical anesthetic adjunct, but its specific mechanism is not fully understood. Therefore, this study aims to explore the effects and mechanisms of dexmedetomidine on cerebral IR injury in mice.

METHODS

The mouse middle cerebral artery occlusion (MCAO) model was prepared by modified suture method. Male ICR mice were randomly divided into a sham group, an IR group, an IR+D1 group (IR+administered 25 µg/kg dexmedetomidine), an IR+D2 group(IR+administered 50 µg/kg dexmedetomidine), an IR+D3 group (IR+administered 100 µg/kg dexmedetomidine), and an IR+D2+ML385 group (IR+administered 50 µg/kg dexmedetomidine and 30 mg/kg ML385). The neurologic behavior of mice was evaluated by Longa's five-point method. 2,3,5-triphenyltetrazolium chloride (TTC) staining was used to detect the percentage of cerebral infarct volume in mice. The protein expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), transferrin receptor 1 (TFR1), glutathione peroxidase 4 (GPX4), and solute carrier family 7 member 11 (SLC7A11) in the cerebral tissues of mice were detected by Western blotting.Mitochondrial morphology was observed under the transmission electron microscope. The contents of MDA, Fe2+, and GSH in the cerebral tissues of mice were detected.

RESULTS

Compared with the sham group, neurobehavioral scores, cerebral infarct volume, the contents of MDA and Fe2+, as well as the protein expression of TFR1 were significantly increased; the contents of GSH and the protein expression of SLC7A11 and GPX4 were significantly reduced (all P<0.05); mitochondria in cerebral tissue were wrinkled, cristae were reduced, and membrane density was increased in the IR group. Compared with the IR group, neurobehavioral scores, cerebral infarction volume, MDA and Fe2+ contents, as well as the protein expression of TFR1 were significantly reduced; the contents of GSH and the protein expression of SLC7A11 and GPX4 were significantly increased (all P<0.05); mitochondrial damage in cerebral tissue was significantly relieved with the pre-treatment of dexmedetomidine. Compared with the IR+D2 group, neurobehavioral scores, cerebral infarction volume, MDA and Fe2+ contents, as well as the protein expression of TFR1 were significantly increased; the contents of GSH and the protein expression of SLC7A11 and GPX4 were significantly reduced (all P<0.05);mitochondria reappeared significantly damaged with the ML385 on the basis of dexmedetomidine pre-treatment.

CONCLUSIONS

The protective effect of dexmedetomidine on cerebral IR injury mice is related to its inhibition of ferroptosis, and the mechanism might be related to its regulation of Nrf2 expression.

Stroke risk after ocular cranial nerve palsy - A systematic review and meta-analysis

BACKGROUND

Isolated ischemic ocular cranial nerve palsies (OCNP) involving the 3rd, 4th and 6th cranial nerves (CN) are prevalent conditions in ophthalmic practice. However, it is not clearly established whether such patients are at increased risk of stroke after onset of OCNPs.

METHODS

Medline, PubMed, Embase and Cochrane Central registers were systematically searched for eligible studies comparing isolated ischemic OCNPs against matched controls on the subsequent development of stroke with at least two years of follow up. Case reports and series were excluded. Appropriate studies were entered for meta-analysis to determine hazard ratios. Search and data extraction was completed on 22 Feb 2021. Random effect models were used to generate pooled hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Three studies were suitable for meta-analysis (total n = 2,756 OCNP cases and 21,239 matched controls). The meta-analysis demonstrated a hazard ratio of 5.96 (4.20-8.46 95% CI) of subsequent stroke after isolated OCNP within the first year. The hazard ratio reduced to 3.27 (2.61-4.10 95% CI) after five years although remains raised at 2.49 (1.53-4.06 95% CI) up to 12 years. The highest risk was demonstrated with 3rd cranial nerve palsies. Two additional studies assessed the risk of stroke with newly diagnosed diabetics and compared OCNPs against lacunar stroke. These studies did not demonstrate a significant increased risk of stroke, although they may be statistically underpowered.

CONCLUSION

Ischemic OCNPs represent a significant risk factor for development of subsequent stroke in a similar magnitude to transient ischemic attack within the first year.

Evaluation of microalbuminuria as a prognostic indicator after a TIA or minor stroke in an outpatient setting: the prognostic role of microalbuminuria in TIA evolution (ProMOTE) study

OBJECTIVE

Transient ischaemic attacks (TIA) and minor strokes are important risk factors for further vascular events. We explored the role of albumin creatinine ratio (ACR) in improving risk prediction after a first event.

SETTING

Rapid access stroke clinics in the UK.

PARTICIPANTS

2202 patients attending with TIA or minor stroke diagnosed by the attending stroke physician, able to provide a urine sample to evaluate ACR using a near-patient testing device.

PRIMARY AND SECONDARY OUTCOMES

Primary outcome was major adverse cardiac events (MACE: recurrent stroke, myocardial infarction or cardiovascular death) at 90 days. The key secondary outcome was to determine whether urinary ACR could contribute to a risk prediction tool for use in a clinic setting.

RESULTS

151 MACE occurred in 144 participants within 90 days. Participants with MACE had higher ACR than those without. A composite score awarding a point each for age >80 years, previous stroke/TIA and presence of microalbuminuria identified those at low risk and high risk. 90% of patients were at low risk (scoring 0 or 1). Their 90-day risk of MACE was 5.7%. Of the remaining 'high-risk' population (scoring 2 or 3) 12.4% experienced MACE over 90 days (p<0.001 compared with the low-risk population). The need for acute admission in the first 7 days was twofold elevated in the high-risk group compared with the low-risk group (3.23% vs 1.43%; p=0.05). These findings were validated in an independent historic sample.

CONCLUSION

A risk score comprising age, previous stroke/TIA and microalbuminuria predicts future MACE while identifying those at low risk of a recurrent event. This tool shows promise in the risk stratification of patients to avoid the admission of low-risk patients.

An International Report on the Adaptations of Rapid Transient Ischaemic Attack Pathways During the COVID-19 Pandemic

Background

This report aims to describe changes that centres providing transient ischaemic attack (TIA) pathway services have made to stay operational in response to the SARS-CoV-2 pandemic.

Methods

An international cross-sectional description of the adaptions of TIA pathways between 30^th March and 6^th May 2020. Experience was reported from 18 centres with rapid TIA pathways in seven countries (Australia, France, UK, Canada, USA, New Zealand, Italy, Canada) from three continents.

Results

All pathways remained active (n = 18). Sixteen (89%) had TIA clinics. Six of these clinics (38%) continued to provide in-person assessment while the majority (63%) used telehealth exclusively. Of these, three reported PPE use and three did not. Five centres with clinics (31%) had adopted a different vascular imaging strategy.

Conclusion

The COVID pandemic has led TIA clinics around the world to adapt and move to the use of telemedicine for outpatient clinic review and modified investigation pathways. Despite the pandemic, all have remained operational.

The role of microglia in ischemic preconditioning

Ischemic preconditioning (IPC) is an experimental phenomenon in which a brief ischemic stimulus confers protection against a subsequent prolonged ischemic event. Initially thought to be due to mechanistic changes in neurons, our understanding of IPC has evolved to encompass a global reprogramming of the Central Nervous System (CNS) after transient ischemia/reperfusion that requires innate immune signaling pathways including Toll-like receptors (TLRs) and Type I interferons. Microglia are the CNS resident neuroimmune cells that express these key innate immune receptors. Studies suggest that microglia are required for IPC-mediated neuronal and axonal protection. Multiple paradigms targeting TLRs have converged on a distinctive Type I interferon response in microglia that is critical for preconditioning-mediated protection against ischemia. These pathways can be targeted through administration of TLR agonists, cytokines including interferon-β, and pharmaceutical agents that induce preconditioning through cross-tolerance mechanisms. Transcriptomic analyses and single cell RNA studies point to specific gene expression signatures in microglia that functionally shift these mutable cells to an immunomodulatory or protective phenotype. Although there are technological challenges and gaps in knowledge to overcome, the targeting of specific molecular signaling pathways in microglia is a promising direction for development of novel and effective pharmacotherapies for stroke. Studies on preconditioning in animal models, including nonhuman primates, show promise as prophylactic preconditioning treatments for selected at risk patient populations. In addition, our growing understanding of the mechanisms of IPC-mediated protection is identifying novel cellular and molecular targets for therapeutic interventions that could apply broadly to both acute stroke and chronic vascular cognitive impairment patients.