Small vessel cerebrovascular disease: the past, present, and future

Spiral time-of-flight magnetic resonance angiography for intracranial vascular imaging: performance compared to conventional Cartesian angiogram

Background

Computed tomography angiography (CTA) and digital subtraction angiography (DSA) usually raise the risk of potential malignancies with cumulative radiation doses. Current time-of-flight magnetic resonance angiography (TOF-MRA) (dubbed as cTOF), which is based on Cartesian sampling mode, may show limited diagnostic conspicuity at sinuous or branching regions. It is also prone to relatively high false positive diagnoses and undesirable display of distal intracranial vessels. This study aimed to use spiral TOF-MRA (sTOF) as a noninvasive alternative to explore possible improvement, such that the application of magnetic resonance angiography (MRA) can be extended to facilitate clinical examination or cerebrovascular disease diagnosis and follow-up studies.

Methods

Initially, 37 patients with symptoms of dizziness or transient ischemic attack were consecutively recruited for suspected intracranial vascular disease examination from Zhongshan Hospital of Xiamen University between July 2020 and April 2021 in this cross-sectional prospective study. After excluding 1 patient with severe scanning artifacts, 1 patient whose scanning scope did not meet the requirement, and 1 patient with confounding tumor lesions, a total of 34 participants were included according to the inclusion and exclusion criteria. Each participant underwent intracranial vascular imaging with both sTOF and cTOF sequences on a 3.0 T MR scanner with a conventional head-neck coil of 16 channels. Contrast CTA or DSA was also performed for 15 patients showing pathology. Qualitative comparisons in terms of image quality and diagnostic efficacy ratings, quantitative comparisons in terms of signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), vessel length, and sharpness were evaluated. Pair-wise Wilcoxon test was performed to evaluate the imaging quality derived from cTOF and sTOF acquisitions and weighted Cohen's Kappa was conducted to assess the rating consistency between different physicians.

Results

Compared to cTOF, sTOF showed better performance with fewer artifacts. It can effectively alleviate false positives of normal vessels being misdiagnosed as aneurysm or stenosis. Improved conspicuity was observed in cerebral distal regions with more clearly identifiable vasculature at finer scales. Quantitative comparisons in selected regions revealed significant improvement of sTOF in SNR (P<0.01 or P<0.001), CNR (P<0.001), vessel length (P<0.001), and sharpness (P<0.001) as compared to cTOF. Besides, sTOF can depict details of M1 and M2 segments of middle cerebral artery (MCA) at metallic implant region, showing its resistance to magnetic susceptibility.

Conclusions

The sTOF shows higher imaging quality and lesion detectability with reduced artifacts and false positives, representing a potentially feasible surrogate in intracranial vascular imaging for future clinic routines.

Prevalence of Stroke-Associated Pneumonia and Its Predictors Among Hyperglycaemia Patients During Acute Ischemic Stroke

BACKGROUND

Hyperglycaemia (HG) during an acute ischemic stroke (AIS) is not only associated with unfavourable functional outcomes but also associated with stroke-associated pneumonia (SAP). This study aimed to determine the prevalence of SAP among Malaysian patients with AIS and the predictors of SAP among patients with HG during AIS.

METHODS

This is a retrospective cross-sectional study that included patients with AIS admitted to Hospital Sultanah Nur Zahirah, Malaysia from 2017 to 2020. SAP was defined as infection with pneumonia during the first seven days after IS. HG was defined as a blood glucose level > 7.8 mmol/L within 72 h after admission. Patients with SAP were divided into two groups according to HG status. Multivariate logistic regression analysis was performed using SPSS software, version 22 (IBM Corp., Armonk, NY) to identify SAP predictors among patients with HG. Kaplan-Meier log-rank test was used to compare the survival rate from unfavourable functional outcomes between hyperglycaemic patients with and without SAP.

RESULTS

Among 412 patients with AIS, 69 (16.74%) had SAP. The prevalence of SAP among patients with HG and normoglycemia during AIS was 20.98%, and 10.65%, respectively. Age above 60 years, leucocytosis, and National Institute of Health Stroke Scale (NIHSS) > 14 on admission were independent predictors of SAP with aOR of 2.08 (95% CI;1.01-4.30), 2.83 (95% CI; 1.41-5.67), and 3.67 (95% CI; 1.53-8.80), respectively. No significant difference in unfavourable functional outcomes survival was found among patients with and without SAP (p = 0.653).

CONCLUSION

This study demonstrated the prevalence of SAP was higher among patients with HG compared to normoglycemia during AIS. The patient being old, leucocytosis and severe stroke upon admission predict the occurrence of SAP among patients with HG during AIS.

Obstructive Sleep apnea and cardiovascular events in Elderly Patients

INTRODUCTION

In recent decades, life expectancy has increased considerably. The cardiovascular effects of Obstructive Sleep Apnea (OSA) in the elderly lead to patient disability and high resource consumption. Intermittent nocturnal hypoxia leads to hemodynamic stress and adrenergic activation, which promotes cardiovascular disease. However, chronic intermittent hypoxia may protect elderly patients from cardiovascular events (CVE) due to biological adaptation.

AREAS COVERED

OSA patients are at increased risk of cardiovascular events. The severity of OSA increases cardiovascular risk, and this association also exists in the elderly. This article reviews the association between OSA, CPAP treatment, and CVE, particularly stroke and coronary heart disease (CHD), in the elderly. MEDLINE and the Cochrane Collaboration databases were searched from inception to July 2021.

EXPERT COMMENTARY

Although a positive association between OSA and the incidence of cardiovascular disease in the elderly has been established, the role of sleep apnea in certain cardiovascular events remains controversial. Most authors agree that untreated OSA is a risk factor for stroke or worse stroke prognosis. However, the association between OSA and CHD is usually less pronounced than between OSA and stroke, especially in the elderly.

Long-term mortality and recurrent vascular events in lacunar versus non-lacunar ischaemic stroke: A cohort study

Introduction

Studies of differences in very long-term outcomes between people with lacunar/small vessel disease (SVD) versus other types of ischaemic stroke report mixed findings, with limited data on myocardial infarction (MI). We investigated whether long-term mortality, recurrent stroke and MI risks differ in people with versus without lacunar/SVD ischaemic stroke.

Patients and methods

We included first-ever strokes from a hospital-based stroke cohort study recruited in 2002–2005. We compared risks of death, recurrent stroke and MI during follow-up among lacunar/SVD versus other ischaemic stroke subtypes using Cox regression, adjusting for confounding factors.

Results

We included 812 participants, 283 with lacunar/SVD ischaemic stroke and 529 with other stroke. During a median of 9.2 years (interquartile range 3.1–11.8), there were 519 deaths, 181 recurrent strokes and 79 MIs. Lacunar/SVD stroke was associated with lower mortality (adjusted HR 0.79, 95% CI 0.65 to 0.95), largely due to markedly lower all-cause mortality in the first year. From one year onwards this difference attenuated, with all-cause mortality only slightly and not statistically significantly lower in the lacunar/SVD group (0.86, 95% CI 0.70 to 1.05). There was no clear difference in risk of recurrent stroke (HR 0.84, 95% CI 0.61–1.15) or MI (HR 0.83, 95% CI 0.52–1.34).

Conclusion

Long-term risks of all-cause mortality, recurrent stroke and MI are similar, or only slightly lower, in patients with lacunar/SVD as compared to other ischaemic stroke. Patients and physicians should be as vigilant in optimising short- and long-term secondary prevention of vascular events in lacunar/SVD as for other stroke types.

Optical measures of cerebral arterial stiffness are associated with white matter signal abnormalities and cognitive performance in normal aging

Decline in fluid abilities in normal aging is associated with increased white matter lesions, measured on T1-weighted images as white matter signal abnormalities (WMSAs). WMSAs are particularly evident in hypertensive older adults, suggesting vascular involvement. However, because hypertension is assessed systemically, the specific role of cerebral arterial stiffening in WMSAs has yet to be demonstrated. In 93 cognitively normal adults (aged 18-87 years), we used a novel method to measure cerebral arterial elasticity (pulse relaxation function [PReFx]) with diffuse optical tomography (pulse-DOT) and investigated its association with WMSAs, age, and cognition. PReFx was associated with WMSAs, with older adults with low PReFx showing the greatest WMSA burden. PReFx in brain regions perfused by the middle cerebral artery showed the largest associations with WMSAs and partially mediated the relationship between age and WMSAs. Finally, WMSAs partially mediated the relationship between PReFx and fluid but not crystallized abilities scores. Taken together, these findings suggest that loss of cerebral arterial elasticity is associated with cerebral white matter lesions and age-related cognitive decline.

Synergistic Anti-Angiogenic Effects Using Peptide-Based Combinatorial Delivery of siRNAs Targeting VEGFA, VEGFR1, and Endoglin Genes

Angiogenesis is a process of new blood vessel formation, which plays a significant role in carcinogenesis and the development of diseases associated with pathological neovascularization. An important role in the regulation of angiogenesis belongs to several key pathways such as VEGF-pathways, TGF-β-pathways, and some others. Introduction of small interfering RNA (siRNA) against genes of pro-angogenic factors is a promising strategy for the therapeutic suppression of angiogenesis. These siRNA molecules need to be specifically delivered into endothelial cells, and non-viral carriers modified with cellular receptor ligands can be proposed as perspective delivery systems for anti-angiogenic therapy purposes. Here we used modular peptide carrier L1, containing a ligand for the CXCR4 receptor, for the delivery of siRNAs targeting expression of VEGFA, VEGFR1 and endoglin genes. Transfection properties of siRNA/L1 polyplexes were studied in CXCR4-positive breast cancer cells MDA-MB-231 and endothelial cells EA.Hy926. We have demonstrated the efficient down-regulation of endothelial cells migration and proliferation by anti-VEGFA, anti-VEGFR1, and anti-endoglin siRNA-induced silencing. It was found that the efficiency of anti-angiogenic treatment can be synergistically improved via the combinatorial delivery of anti-VEGFA and anti-VEGFR1 siRNAs. Thus, this approach can be useful for the development of therapeutic angiogenesis inhibition.

Twenty-and-a-half syndrome: a case report

Background

In the list of named numerical neuro-ophthalmological syndromes, such as one-and-a-half syndrome and others, we report for the first time twenty-and-a-half syndrome, which is characterized by one-and-a-half syndrome with bilateral seventh and right fifth nerve palsy (1.5 + 7 + 7 + 5 = 20.5) in a patient with ischemic stroke.

Case presentation

A 45-year-old Asian Hindu woman presented with vomiting and imbalance of 1 day’s duration. She had left-sided ataxic hemiparesis with one-and-a-half syndrome with bilateral seventh and right fifth nerve palsy. Magnetic resonance imaging of her brain revealed acute non-hemorrhagic infarct in the right posterolateral aspect of pons and medulla, with normal brain vessels angiography. We described her disorder as twenty-and-a-half syndrome. She was put on antiplatelet therapy.

Conclusions

Twenty-and-a-half syndrome is reported for the first time. It is due to posterior circulation stroke; in our case, it was due to lacunar infarcts in the pons and medulla, manifesting as one-and-a-half syndrome with bilateral seventh and right fifth nerve palsy.

Improvement of postoperative cognitive dysfunction and attention network function of patients with ischemic cerebrovascular disease via dexmedetomidine

The protective effect of dexmedetomidine on cognitive dysfunction and decreased attention network function of patients with ischemic cerebrovascular disease after stenting was investigated. Fifty-eight patients with ischemic cerebrovascular disease undergoing stenting in Guizhou Provincial People's Hospital were selected and randomly divided into control group (n=29) and dexmedetomidine group (n=29). The dexmedetomidine group was treated with dexmedetomidine before induced anesthesia, while the control group was given the same dose of normal saline; and the normal volunteers of the same age were selected as the normal group (n=29). At 3 days after operation, the levels of serum S100B and nerve growth factor (NGF) in each group were detected using the enzyme-linked immunosorbent assay, and the level of brain-derived neurotrophic factor (BDNF) was detected via western blotting. Montreal cognitive assessment (MoCA) and attention network test (ANT) were performed. Moreover, the cognitive function and attention network function, and the effects of dexmedetomidine on cognitive function and attention network function were evaluated. The concentrations of serum S100B and NGF in dexmedetomidine group was lower than those in control group (P<0.01). The results of western blotting showed that the levels of serum BDNF in control group and dexmedetomidine group were significantly lower than that in normal group (P<0.01), and it was higher in dexmedetomidine group than that in control group (P<0.01). Besides, both MoCA and ANT results revealed that the visual space and executive function scores, attention scores, delayed memory scores, targeted network efficiency and executive control network efficiency in dexmedetomidine group were obviously higher than those in control group (P<0.01). The cognitive function and attention network function of patients with ischemic cerebrovascular disease have a certain degree of damage, and the preoperative administration of dexmedetomidine can effectively improve the patient's cognitive dysfunction and attention network function after operation.

[Frequency and characteristics of strokes involving the perforating arteries in the Department of Neurology at the Befelatanana General Hospital, Antananarivo]

Introduction

Strokes of the perforating arteries are mainly arteriolopathies. They result in dementia and stroke recurrence. This study aimed to evaluate the frequency and characteristics of these strokes to better prevent these complications.

Methods

We conducted a descriptive, retrospective study in the department of neurology at the Befelatanana general hospital, Antananarivo over the period 01 March-25 September 2015. All patients with abrupt neurological deficit and deep brain involvement on brain scanner were included in the study. The features of strokes involving the perforating arteries were collected. Data were processed with SPSS 20 software.

Results

Out of 172 patients with a stroke, 83(48.25%) had stroke involving the perforating arteries. Stroke involving the perforating arteries affected young people (65.06%) aged less than 65 years and preferentially the male population (61.44%). Haemorrhagic forms accounted for 67.46%. Thirty-one patients (37.34%) had stroke recurrences and, among them, almost a quarter had 2 recurrences (38.70%) in less than a year. All patients with recurrence had dysexecutive disorder (p < 0.0001) and poor antihypertensive medication adherence. Mortality accounted for only 6.02% in patients with onset of these strokes during hospitalization.

Conclusion

Specific neurologic follow-up is necessary after a first stroke involving perforating arteries in order to make an early diagnosis of dementia and to prevent recurrences.

Retinal microvascular network alterations: potential biomarkers of cerebrovascular and neural diseases

Increasing evidence suggests that the conditions of retinal microvessels are indicators to a variety of cerebrovascular, neurodegenerative, psychiatric, and developmental diseases. Thus noninvasive visualization of the human retinal microcirculation offers an exceptional opportunity for the investigation of not only the retinal but also cerebral microvasculature. In this review, we show how the conditions of the retinal microvessels could be used to assess the conditions of brain microvessels because the microvascular network of the retina and brain share, in many aspects, standard features in development, morphology, function, and pathophysiology. Recent techniques and imaging modalities, such as optical coherence tomography (OCT), allow more precise visualization of various layers of the retina and its microcirculation, providing a "microscope" to brain microvessels. We also review the potential role of retinal microvessels in the risk identification of cerebrovascular and neurodegenerative diseases. The association between vision problems and cerebrovascular and neurodegenerative diseases, as well as the possible role of retinal microvascular imaging biomarkers in cerebrovascular and neurodegenerative screening, their potentials, and limitations, are also discussed.

In Vitro Study of a Superhydrophilic Thin Film Nitinol Endograft that is Electrostatically Endothelialized in the Catheter Prior to the Endovascular Procedure

Electrostatic endothelial cell seeding has evolved as an exceptional technique to improve the efficiency of cell seeding in terms of frequency of attached cells and the amount of cell adhesion for the treatment of vascular diseases. In the recent times, both untreated and superhydrophilic thin film nitinol (TFN) have exhibited strong prospects as substrates for creation of small-diameter endovascular grafts due to their hallmark properties of superelasticity, ultra low-profile character, and grown hemocompatible oxide layer with the presence of a uniform endothelial layer on the surface. The purpose of the current study is to understand the effects of endothelial cell seeding parameters (i.e., applied voltage, incubation time, substrate chemistry, and cell suspension solution) to investigate the cell seeding phenomenon and to improve the cell adhesion and growth on the TFN surface under electrostatic transplantation. Both parallel plate and cylindrical capacitor models were used along with the Taguchi Design of Experiment (DOE) methods to design in vitro test parameters. A novel in vitro system for a cylindrical capacitor model was created using a micro flow pump, micro incubation system, and silicone tubings. The augmented endothelialization on thin film nitinol was developed to determine the effect of cell seeding and deployed in a 6 Fr intravascular catheter setup. Cell viability along with morphology and proliferation of adhered cells were evaluated using fluorescent and scanning electron microscopy. Our results demonstrated that the maximum number of cells attached on STFN in the catheter was observed in 5 V with the 2 h exposure of in the cell culture medium (CCM) solution. The condition showed 5 V voltage with 0.68 × 10^-6 µC electrostatic charge and 5.11 V·mm^-1 electric field. Our findings have first demonstrated that the electrostatic endothelialization on the superhydrophilic thin film nitinol endograft within the catheter prior to the endovascular procedure could enhance the biocompatibility for low-profile endovascular applications.

Beyond antiplatelets: The role of glycoprotein VI in ischemic stroke

Background

Platelets are essential to physiological hemostasis or pathological thrombus formation. Current antiplatelet agents inhibit platelet aggregation but leave patients at risk of systemic side-effects such as hemorrhage. Newer therapeutic strategies could involve targeting this cascade earlier during platelet adhesion or activation via inhibitory effects on specific glycoproteins, the thrombogenic collagen receptors found on the platelet surface.

Aims

Glycoprotein VI (GPVI) is increasingly being recognized as the main platelet-collagen receptor involved in arterial thrombosis. This review summarizes the crucial role GPVI plays in ischemic stroke as well as the current strategies used to attempt to inhibit its activity.

Summary of review

In this review, we discuss the normal hemostatic process, and the role GPVI plays at sites of atherosclerotic plaque rupture. We discuss how the unique structure of GPVI allows for its interaction with collagen and creates downstream signaling that leads to thrombus formation. We summarize the current strategies used to inhibit GPVI activity and how this could translate to a clinically viable entity that may compete with current antiplatelet therapy.

Conclusion

From animal models, it is clear that GPVI inhibition leads to an abolished platelet response to collagen and reduced platelet aggregation, culminating in smaller arterial thrombi. There is now an increasing body of evidence that these findings can be translated into the development of a bleeding free pharmacological entity specific to sites of plaque rupture in humans.

Stroke subtypes and factors associated with ischemic stroke in Kinshasa, Central Africa

BACKGROUND AND PURPOSE

Ischemic stroke causes death and disability worldwide. Better understanding and controlling factors associated will improve the prevention of the disease. This study reviews records of patients with ischemic stroke in Central Africa.

MATERIAL AND METHODS

Patients of Bantu ethnicity with clinical diagnosis of stroke and lesion on computed tomography scan from January 2011 to December 2012 were selected. Computed tomographic subtypes of ischemic stroke and factors associated were considered with tropical seasonal variation.

RESULTS

Of the 303 first-ever stroke patients (average age 53 years old, range 3- 84 years old; 62% male) were included in the study. The prevalence of computed tomography stroke subtypes was: lacunar infarct (63%) and non lacunar infarct lesion (37%). Silent brain infarct was seen in 9 % of patients. Prevalence of factors associated with ischemic stroke was: age≥60 years old (55%); male gender (63%), chronic and uncontrolled hypertension (54%) and type 2 Diabetes mellitus (11%). A seasonal high prevalence was observed in warmer season (p < 0.05).

CONCLUSIONS

This study shows a high prevalence of lacunar infarct than non lacunar in Bantu of Central Africa.

Ultrasound-enhanced protective effect of tetramethylpyrazine against cerebral ischemia/reperfusion injury

In traditional Chinese medicine, Ligusticum wallichii (Chuan Xiong) and its bioactive ingredient, tetramethylpyrazine (TMP), have been used to treat cardiovascular diseases and to relieve various neurological symptoms, such as those associated with ischemic injury. In the present study, we investigated whether ultrasound (US) exposure could enhance the protective effect of TMP against cerebral ischemia/reperfusion (I/R) injury. Glutamate-induced toxicity to pheochromocytoma (PC12) cells was used to model I/R injury. TMP was paired with US to examine whether this combination could alleviate glutamate-induced cytotoxicity. The administration of TMP effectively protected cells against glutamate-induced apoptosis, which could be further enhanced by US-mediated sonoporation. The anti-apoptotic effect of TMP was associated with the inhibition of oxidative stress and a change in the levels of apoptosis-related proteins, Bcl-2 and Bax. Furthermore, TMP reduced the expression of proinflammatory cytokines such as TNF-α and IL-8, which likely also contributes to its cytoprotective effects. Taken together, our findings suggest that ultrasound-enhanced TMP treatment might be a promising therapeutic strategy for ischemic stroke. Further study is required to optimize ultrasound treatment parameters.

Outdoor air pollution, subtypes and severity of ischemic stroke--a small-area level ecological study

Background

Evidence linking outdoor air pollution and incidence of ischemic stroke subtypes and severity is limited. We examined associations between outdoor PM₁₀ and NO₂ concentrations modeled at a fine spatial resolution and etiological and clinical ischemic stroke subtypes and severity of ischemic stroke.

Methods

We used a small-area level ecological study design and a stroke register set up to capture all incident cases of first ever stroke (1995–2007) occurring in a defined geographical area in South London (948 census output areas; population of 267839). Modeled PM₁₀ and NO₂ concentrations were available at a very fine spatial scale (20 meter by 20 meter grid point resolution) and were aggregated to output area level using postcode population weighted averages. Ischemic stroke was classified using the Oxford clinical classification, the Trial of Org 10172 in Acute Stroke Treatment (TOAST) etiological classification, National Institutes of Health Stroke Scale (NIHSS) score and a pragmatic clinical severity classification based on Glasgow coma score, ability to swallow, urinary continence and death <2 days of stroke onset.

Results

Mean (SD) concentrations were 25.1 (1.2) ug/m³ (range 23.3-36.4) for PM₁₀ and 41.4 (3.0) ug/m³ (range 35.4-68.0) for NO₂. There were 2492 incident cases of ischemic stroke. We found no evidence of association between these pollutants and the incidence of ischemic stroke subtypes classified using the Oxford and TOAST classifications. We found no significant association with stroke severity using NIHSS severity categories. However, we found that outdoor concentrations of both PM₁₀ and NO₂ appeared to be associated with increased incidence of mild but not severe ischemic stroke, classified using the pragmatic clinical severity classification. For mild ischemic stroke, the rate ratio in the highest PM₁₀ category by tertile was 1.20 (1.05-1.38) relative to the lowest category. The rate ratio in the highest NO₂ category was 1.22 (1.06-1.40) relative to the lowest category.

Conclusions

We found no evidence of association between outdoor PM₁₀ and NO₂ concentrations and ischemic stroke subtypes but there was a suggestion that living in areas with elevated outdoor PM₁₀ and NO₂ concentrations might be associated with increased incidence of mild, but not severe, ischemic stroke.

Small vessel disease and memory loss: what the clinician needs to know to preserve patients' brain health

Small vessel disease (SVD) in the brain manifests in the periventricular and deep white matter and radiographically is described as "leukoaraiosis". It is increasingly recognized as a cause of morbidity from middle age onward and this clinical relevance has paralleled advances in the field of neuroradiology. Overall, SVD is a heterogenous group of vascular disorders that may be asymptomatic, or a harbinger of many conditions that jeopardize brain health. Management and prevention focuses on blood pressure control, lifestyle modification, and symptomatic treatment.

Angiotensin-converting enzyme gene insertion/deletion polymorphism and small vessel cerebral stroke in Indian population

Background. Hypertension is an established risk factor for small-vessel cerebral stroke and the renin-angiotensin system plays an important role in the maintenance of blood pressure. We aimed at evaluating the contribution of the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism to the risk of small-vessel stroke in south Indian population. Materials and Methods. We investigated 128 patients diagnosed with small-vessel stroke and 236 age, and gender-matched healthy controls. ACE I/D polymorphism was detected by polymerase chain reaction. Results. Hypertension was significantly more prevalent in the patient group and was associated with 6-fold increase in risk for stroke. ACE genotypes were in Hardy-Weinberg equilibrium in both patients and controls. Prevalence of DD, ID, and II genotypes in cases (34.4%, 43.7%, and 28%) did not differ significantly from controls (31.8%, 43.2%, and 25%). The polymorphism was not associated with small-vessel stroke (OR: 1.34; 95% CI: 0.52–1.55). However, diastolic blood pressure was associated with the ACE I/D genotypes in the patients. (DD; 90.2 ± 14.2> ID; 86.2 ± 11.9> II; 82.3 ± 7.8 mm Hg,  P = 0.047). Conclusion. Our study showed that hypertension, but not ACE I/D polymorphism, increased the risk of small-vessel stroke.

Significance of Haemodynamic and Haemostatic Factors in the Course of Different Manifestations of Cerebral Small Vessel Disease: The SHEF-CSVD Study-Study Rationale and Protocol

Rationale. This paper describes the rationale and design of the SHEF-CSVD Study, which aims to determine the long-term clinical and radiological course of cerebral small vessel disease (CSVD) and to evaluate haemostatic and haemodynamic prognostic factors of the condition. Design. This single-centre, prospective, non-interventional cohort study will follow 150 consecutive patients with different clinical manifestations of CSVD (lacunar ischaemic stroke, vascular dementia, vascular parkinsonism or spontaneous deep, intracerebral haemorrhage) and 50 age- and sex-matched controls over a period of 24 months. The clinical and radiological course will be evaluated basing on a detailed neurological, neuropsychological and MRI examinations. Haemodynamic (cerebral vasoreactivity, 24 h blood pressure control) and haemostatic factors (markers of endothelial and platelet dysfunction, brachial artery flow-mediated dilatation test) will be determined. Discussion. The scheduled study will specifically address the issue of haemodynamic and haemostatic prognostic factors and their course over time in various clinical manifestations of CSVD. The findings may aid the development of prophylactic strategies and individualised treatment plans, which are critical during the early stages of the disease.

The vascular neural network--a new paradigm in stroke pathophysiology

The concept of the neurovascular unit as the key brain component affected by stroke is controversial, because current definitions of this entity neglect mechanisms that control perfusion and reperfusion of arteries and arterioles upstream of the cerebral microcirculation. Indeed, although definitions vary, many researchers consider the neurovascular unit to be restricted to endothelial cells, neurons and glia within millimetres of the cerebral capillary microcirculation. This Perspectives article highlights the roles of vascular smooth muscle, endothelial cells and perivascular innervation of cerebral arteries in the initiation and progression of, and recovery from, ischaemic stroke. The concept of the vascular neural network-which includes cerebral arteries, arterioles, and downstream neuronal and glial cell types and structures-is introduced as the fundamental component affected by stroke pathophysiology. The authors also propose that the vascular neural network should be considered the main target for future therapeutic intervention after cerebrovascular insult.