Silent Ischemic Brain Research Articles

Silent brain ischemia within the TAXINOMISIS framework: association with clinical and advanced ultrasound metrics

IntroductionThe relationship between carotid artery stenosis (CAS) and ipsilateral silent brain ischemia (SBI) remains unclear, with uncertain therapeutic implications. The present study, part of the TAXINOMISIS project (nr. 755,320), aimed to investigate SBIs in patients with asymptomatic CAS, correlating them with clinical, carotid ultrasonographic data, and CFD analyses.MethodsThe TAXINOMISIS clinical trial study (nr. NCT03495830) involved six vascular surgery centers across Europe, enrolling patients with asymptomatic and symptomatic CAS ranging from 50 to 99%. Patients underwent carotid ultrasound and magnetic resonance imaging (MRI), including brain diffusion-weighted, T2-weighted/FLAIR, and T1-weighted sequences. Brain MRI scans were analyzed for the presence of SBI according to established definitions. Ultrasound assessments included Doppler and CFD analysis. Only asymptomatic patients were included in this substudy.ResultsAmong 195 asymptomatic patients, the mean stenosis (NASCET) was 64.1%. Of these, a total of 33 patients (16.9%) had at least one SBI detected on a brain MRI scan. Specifically, 19 out of 33 patients (57.6%) had cortical infarcts, 4 out of 33 patients (12.1%) had ipsilateral lacunar infarcts, 6 out of 33 patients had (18.2%) subcortical infarcts, 1 out of 33 patients (3.0%) had both cortical and lacunar infarcts, and 3 out of 33 patients (9.1%) both cortical and subcortical infarcts. Patients with SBIs exhibited significantly higher risk factors, including a higher body mass index (28.52 ± 9.38 vs. 26.39 ± 3.35, p = 0.02), diastolic blood pressure (80.87 ± 15.73 mmHg vs. 80.06 ± 8.49 mmHg, p = 0.02), creatinine levels (93.66 ± 34.61 μmol/L vs. 84.69 ± 23.67 μmol/L, p = 0.02), and blood triglycerides (1.8 ± 1.06 mmol/L vs. 1.48 ± 0.78 mmol/L, p = 0.03). They also had a higher prevalence of cardiovascular interventions (29.6% vs. 13.8%, p = 0.04), greater usage of third/fourth-line antihypertensive treatment (50%vs16%, p = 0.03), and anticoagulant medications (60% vs. 16%, p = 0.01). Additionally, the number of contralateral cerebral infarcts was higher in patients with SBIs (35.5% vs. 13.4%, p < 0.01). Moreover, carotid ultrasound revealed higher Saint Mary’s ratios (15.33 ± 12.45 vs. 12.96 ± 7.99, p = 0.02), and CFD analysis demonstrated larger areas of low wall shear stress (WSS) (0.0004 ± 0.0004 m2 vs. 0.0002 ± 0.0002 m2, p < 0.01).ConclusionThe TAXINOMISIS clinical trial provides valuable insights into the prevalence and risk factors associated with SBIs in patients with moderate asymptomatic carotid stenosis. The findings suggest that specific hemodynamic and arterial wall characteristics may contribute to the development of silent brain infarcts.

Prevalence and risk factors of ischemic monocular vision loss and concurrent brain ischemia.

We performed a retrospective cohort study to identify predictors of concurrent asymptomatic brain ischemia in patients with ischemic monocular vision loss. An inpatient database research of admissions to the Helios University Hospital Wuppertal, Germany between 01/2016 and 12/2020 was conducted. Inclusion criteria were confirmed diagnosis of transient monocular vision loss (MVL), retinal artery occlusion (RAO), and magnetic resonance imaging (MRI) of the brain within 10 days of MVL. Silent brain ischemia (SBI) was defined as diffusion restrictions with corresponding reduced apparent diffusion coefficient in MRI and an absence of neurological deficits besides those complying with MVL in clinical examination. The prevalence and cardiovascular predictors of SBI were analyzed with logistic regression and an artificial neural network. One hundred fourteen out of 475 patients treated with monocular vision loss were included in this study. The mean age was 67.7 ± 13.6 years. 48.2% were male and 47.4% had RAO. MRI scan of the brain was performed after 3.9 ± 2.3 days and detected SBI in 17%. Age ⩾67 years, cardiac etiology of MVL, and cerebral ischemia in medical history were revealed as predictors of SBI in MRI. Patients older than 66 years, with a suspected cardiac embolism as the cause of RAO and previous cerebral ischemia, are more likely to present SBI in cerebral MRI. Therefore, MR imaging, particularly in these patients, can be useful.

Nomogram for Prediction of Postoperative Delirium after Deep Brain Stimulation of Subthalamic Nucleus in Parkinson's Disease under General Anesthesia.

Postoperative delirium can increase cognitive impairment and mortality in patients with Parkinson's disease. The purpose of this study was to develop and internally validate a clinical prediction model of delirium after deep brain stimulation of the subthalamic nucleus in Parkinson's disease under general anesthesia. We conducted a retrospective observational cohort study on the data of 240 patients with Parkinson's disease who underwent deep brain stimulation of the subthalamic nucleus under general anesthesia. Demographic characteristics, clinical evaluation, imaging data, laboratory data, and surgical anesthesia information were collected. Multivariate logistic regression was used to develop the prediction model for postoperative delirium. A total of 159 patients were included in the cohort, of which 38 (23.90%) had postoperative delirium. Smoking (OR 4.51, 95% CI 1.56-13.02, p < 0.01) was the most important risk factor; other independent predictors were orthostatic hypotension (OR 3.42, 95% CI 0.90-13.06, p=0.07), inhibitors of type-B monoamine oxidase (OR 3.07, 95% CI 1.17-8.04, p=0.02), preoperative MRI with silent brain ischemia or infarction (OR 2.36, 95% CI 0.90-6.14, p=0.08), Hamilton anxiety scale score (OR 2.12, 95% CI 1.28-3.50, p < 0.01), and apolipoprotein E level in plasma (OR 1.48, 95% CI 0.95-2.29, p=0.08). The area under the receiver operating characteristic curve (AUC) was 0.76 (95% CI 0.66-0.86). A nomogram was established and showed good calibration and clinical predictive capacity. After bootstrap for internal verification, the AUC was 0.74 (95% CI 0.66-0.83). This study provides evidence for the independent inducing factors of delirium after deep brain stimulation of the subthalamic nucleus in Parkinson's disease under general anesthesia. By predicting the development of delirium, our model may identify high-risk groups that can benefit from early or preventive intervention.

Positive Susceptibility Vessel Sign on SWI-MRI Sequence Imaging Might Differentiate Patients Had Silent Brain Ischemia among Apparently Neurologically-Free Patients

Positive Susceptibility Vessel Sign on SWI-MRI Sequence Imaging Might Differentiate Patients Had Silent Brain Ischemia among Apparently Neurologically-Free Patients

Increased serum level of high sensitivity troponin T even prior to surgery can predict adverse events during carotid endarterectomy.

Perioperative stress affects the outcome of carotid endarterectomy performed under regional anesthesia. Here we aimed to explore the temporal profile of the stress marker cortisol and its relationship to high-sensitivity troponin-T, matrix metalloproteinase-9, tissue inhibitor of metalloproteinase-1, and S100B as an indicator of blood-brain barrier alteration in the systemic circulation. Prospective part of the study: a total of 31 patients with significant carotid stenosis scheduled for carotid endarterectomy in regional anesthesia were enrolled. Follow-up part of the study and retrospective analysis of the outcome: each patient was followed up to five years and morbidity as well as mortality data were collected from an electronic database. Blood samples from each patient were serially taken; prior to surgery (T1), at the time of reperfusion (T2), 24 h (T3) and 72 h later postoperatively (T4), then the plasma concentration of each biomarker was measured. Besides, the clinical and surgical factors and perioperative adverse events were recorded. More positive correlations were found between: the early change of S100B (T2-T1) and late change in plasma cortisol level (T4-T3) (r = 0.403; p < 0.05); the early change of cortisol (T2-T1) and the early postoperative change of plasma matrix metalloproteinase-9 level (T3-T2) (r = 0.432; p = 0.01); the plasma concentration of tissue inhibitor of metalloproteinase-1 at 24 postoperative hours and the late change in plasma high-sensitivity troponin-T level (T4-T3) (r = 0.705; p < 0.001). Five patients needed an intraoperative shunt in whom the high-sensitivity troponin-T was elevated even prior to surgery, but definitive stroke never occurred. Plasma matrix metalloproteinase-9 concentration at reperfusion independently predicted the five-year mortality with a cut-off value of 456 ng/ml (sensitivity: 86%, specificity: 84%, area 0.887, p = 0.002). A higher intraoperative change in S100B level reflecting carotid endarterectomy induced acute silent brain ischemia was associated with more pronounced post-operative change of cortisol. An early elevation of cortisol was found to be associated with a delayed increase of matrix metalloproteinase-9. Importantly, an increased high-sensitivity troponin-T even prior to carotid endarterectomy may predict clamp intolerance, and elevated matrix metalloproteinase-9 at reperfusion suggests a poor outcome.

Cranial Magnetic Resonance Imaging as a Screening Tool for Evaluation of Silent Brain Ischemia in Severe Coronary Artery Disease: A Clinical Based Study

Aim: Silent brain ischemia (SBI), defined as ischemic changes and infarcts without neurologic signs, is an established marker of poor survival. Magnetic resonance imaging (MRI) is useful to define SBI and white matter hyperintensities that correspond to microangipathic ischemic disease. This study aimed to investigate the relationship among SBI, white matter lesions and the extent of coronary artery disease (CAD), and to determine possible predictors of SBI.&#x0D; Material and Methods: A total 10640 patients who underwent coronary angiography were retrospectively screened to reveal 312 patients who had been evaluated with a subsequent cranial MRI within 6 months. CAD severity was established with Gensini score and MRIs were evaluated to determine presence of SBI and white matter hyperintensities scored by Fazekas. Finally, 58 patients with SBI and 254 without SBI consisted SBI and non-SBI groups.&#x0D; Results: Patients with SBI were significantly older with higher prevalence of male gender than the non-SBI patients. Both Gensini and Fazekas scores were higher in SBI-group (p

Intraoperative Hypotension is not Correlated to Perioperative Silent Brain Ischemia After Carotid Endarterectomy

Introduction: Periprocedural ischemic brain lesions on diffusion weighted imaging (DWI) after carotid revascularization have increasingly been used as a surrogate marker for cerebral ischemia and are related to a higher chance of recurrent cerebrovascular events. It is hypothesized that patients undergoing carotid endarterectomy with intraoperative hypotension are at risk for development of new silent ischemic lesions as a result of cerebral hypoperfusion. Therefore, the current study aimed to investigate the relation between intraoperative blood pressure (BP) and the presence of silent ischemic lesions on postoperative MR-DWI in patients undergoing carotid endarterectomy. Methods: A retrospective analysis was performed based on prospectively collected data of symptomatic carotid endarterectomy patients within Utrecht Athero-Express (AE) biobank that were also included in the MRI-substudy of the international carotid stenting study (ICSS). Intraoperative hypotension was defined both as a decrease of ≥20% below baseline intraoperative BP and an absolute drop in systolic blood pressure below 80mmHg. Intraoperative hypertension is defined as an increase of ≥20% compared to baseline values. Variation in blood pressure was expressed by it's standard deviation. Intraoperative BP was measured invasively by radial artery cannula. Intraoperative BP was analyzed from time of anesthesia induction until emergence. The occurrence of intraoperative hypo- and hypertension and the duration of these changes in blood pressure were associated to the presence of ischemic lesions on MR-DWI. Results: A number of 55 symptomatic carotid stenosis patients were included in the study of which 71% male patients, with mean age (68.5 ± 9.4) and a median stenosis grade of 70-90%. A total of eight patients had new DWI-lesions (DWI positive) on postoperative MRI (5 ipsilateral and 3 both ipsi- and contralateral). Median lesion volume was 0.37mL (IQR: 0.076-7.81). Baseline characteristics between DWI-negative and DWI-positive patients did not differ. There was no difference in the median duration of intraoperative BP dropping below 80% of baseline in DWI-negative (41 minutes; IQR: 23-82) compared to DWI-positive patients (43 minutes; IQR: 25-81, p=.935). No difference was found in median duration of absolute hypotension (0 minutes; IQR 0-2 vs. 0 minutes; IQR 0-0, p=.224), and intraoperative hypertension (1 minute; IQR 0-2 vs. 1 minute; IQR 0-4, p=.417). The standard deviation of systolic intraoperative BP measurements was also comparable between the groups (24.5; IQR 21.5-28.8 vs 25.7; IQR 22.7-33.6, p=.459). Conclusion: An intraoperative period of relative hypotension compared to baseline occurred frequently. The duration of intraoperative hypotension does not seem to be related to development of perioperative DWI-lesions. Disclosure: Nothing to disclose

Diagnosis and management of carotid free-floating thrombus: A systematic literature review.

There is no consensus regarding the management of carotid free-floating thrombi in patients with acute ischemic stroke and transient ischemic attack. This systematic review aims to (1) describe the current imaging methods for diagnosis of carotid free-floating thrombi and its associated risk factors, (2) estimate the proportion of carotid free-floating thrombi diagnosed in stroke patients, (3) estimate the proportion of carotid free-floating thrombi patients treated medically and surgically, and (4) evaluate 30-day outcomes. We searched MEDLINE, EMBASE, and manually for references reporting carotid free-floating thrombi from 1960 until June 2017. We estimated the frequency of carotid free-floating thrombi and evaluated 30-day outcomes using Cox regression. We defined the timing of surgical intervention as early (less than 72 h) and delayed (more or equal to 72 h). We retrieved 525 carotid free-floating thrombi cases from 58 case series and 83 case reports. Carotid free-floating thrombi were present in 1.53% of stroke patients. Carotid free-floating thrombi diagnosis was made by digital subtraction angiography (38.1%), carotid duplex ultrasound (29.5%), and computed tomography angiography (29.5%). The 30-day risk of transient ischemic attack, silent brain ischemia, any stroke or death was 17.1%. In multivariate analyses, there were no differences in outcome for any anticoagulation regime or timing of revascularization procedure. The diagnosis of carotid free-floating thrombi is more common due to the increased use of early noninvasive vascular imaging in transient ischemic attack and stroke. It poses a high short-term risk of stroke and death, but there is as yet no established treatment. The low quality of evidence in the carotid free-floating thrombi literature limits the interpretation of our results and warrants a large-scale prospective cohort study in carotid free-floating thrombi.

Cardiovascular magnetic resonance assessment of acute cardiovascular effects of voluntary apnoea in elite divers

BackgroundProlonged breath holding results in hypoxemia and hypercapnia. Compensatory mechanisms help maintain adequate oxygen supply to hypoxia sensitive organs, but burden the cardiovascular system.The aim was to investigate human compensatory mechanisms and their effects on the cardiovascular system with regard to cardiac function and morphology, blood flow redistribution, serum biomarkers of the adrenergic system and myocardial injury markers following prolonged apnoea.MethodsSeventeen elite apnoea divers performed maximal breath-hold during cardiovascular magnetic resonance imaging (CMR). Two breath-hold sessions were performed to assess (1) cardiac function, myocardial tissue properties and (2) blood flow. In between CMR sessions, a head MRI was performed for the assessment of signs of silent brain ischemia. Urine and blood samples were analysed prior to and up to 4 h after the first breath-hold.ResultsMean breath-hold time was 297 ± 52 s. Left ventricular (LV) end-systolic, end-diastolic, and stroke volume increased significantly (p < 0.05). Peripheral oxygen saturation, LV ejection fraction, LV fractional shortening, and heart rate decreased significantly (p < 0.05). Blood distribution was diverted to cerebral regions with no significant changes in the descending aorta. Catecholamine levels, high-sensitivity cardiac troponin, and NT-pro-BNP levels increased significantly, but did not reach pathological levels.ConclusionCompensatory effects of prolonged apnoea substantially burden the cardiovascular system. CMR tissue characterisation did not reveal acute myocardial injury, indicating that the resulting cardiovascular stress does not exceed compensatory physiological limits in healthy subjects. However, these compensatory mechanisms could overly tax those limits in subjects with pre-existing cardiac disease. For divers interested in competetive apnoea diving, a comprehensive medical exam with a special focus on the cardiovascular system may be warranted.Trial registrationThis prospective single-centre study was approved by the institutional ethics committee review board. It was retrospectively registered under ClinicalTrials.gov (Trial registration: NCT02280226. Registered 29 October 2014).

Semi-automatic measuring of arteriovenous relation as a possible silent brain infarction risk index in hypertensive patients

Abstract Objective To evaluate the usefulness of a semiautomatic measuring system of arteriovenous relation (RAV) from retinographic images of hypertensive patients in assessing their cardiovascular risk and silent brain ischemia (ICS) detection. Methods Semi-automatic measurement of arterial and venous width were performed with the aid of Imedos software and conventional fundus examination from the analysis of retinal images belonging to the 976 patients integrated in the cohort Investigating Silent Strokes in Hypertensives: a magnetic resonance imaging study (ISSYS), group of hypertensive patients. All patients have been subjected to a cranial magnetic resonance imaging (RMN) to assess the presence or absence of brain silent infarct. Results Retinal images of 768 patients were studied. Among the clinical findings observed, association with ICS was only detected in patients with microaneurysms (OR 2.50; 95% CI : 1.05–5.98) or altered RAV ( Conclusions The results show that the semiautomatic analysis of the retinal vasculature from retinal images has the potential to be considered as an important vascular risk factor in hypertensive population.

Medición semiautomática de la relación arteriovenosa retiniana como posible marcador de riesgo de infarto cerebral silente en pacientes hipertensos

ObjectiveTo evaluate the usefulness of a semiautomatic measuring system of arteriovenous relation (RAV) from retinographic images of hypertensive patients in assessing their cardiovascular risk and silent brain ischemia (ICS) detection. MethodsSemi-automatic measurement of arterial and venous width were performed with the aid of Imedos software and conventional fundus examination from the analysis of retinal images belonging to the 976 patients integrated in the cohort Investigating Silent Strokes in Hypertensives: a magnetic resonance imaging study (ISSYS), group of hypertensive patients. All patients have been subjected to a cranial magnetic resonance imaging (RMN) to assess the presence or absence of brain silent infarct. ResultsRetinal images of 768 patients were studied. Among the clinical findings observed, association with ICS was only detected in patients with microaneurysms (OR 2.50; 95% CI: 1.05-5.98) or altered RAV (<0.666) (OR: 4.22; 95% CI: 2.56-6.96). In multivariate logistic regression analysis adjusted by age and sex, only altered RAV continued demonstrating as a risk factor (OR: 3.70; 95% CI: 2.21-6.18). ConclusionsThe results show that the semiautomatic analysis of the retinal vasculature from retinal images has the potential to be considered as an important vascular risk factor in hypertensive population.

Acetazolamide Stress SPECT Test on Cerebral Blood Flow in Patients with Depressive Disorder

The regional cerebral blood flow (rCBF) and the cerebral vasoreactivity of the patients with depressive disorder were observed by SPECT and acetazolamide stress SPECT test respectively. Eighteen unmedicated depressed patients and nineteen healthy control subjects were included. Baseline SPECT was performed in both patients and control subjects. Acetazolamide stress SPECT test was performed two days later in patients two hours after taking 2g acetazolamide orally. It was found that there was significant difference between the untreated depressed patients and the controls, because there was relatively reduced perfusion in frontal lobe, temporal lobe, left parietal lobe and right basal ganglia in depressed patients. After acetazolamide stress SPECT test, the perfusion of decreased regions in baseline step was increased. No potential ischemic lesion was found. The perfusion of some specific regions of the depressed patients decreased. Acetazolamide stress SPECT test could not reveal silent brain ischemia in the depressed patients. The perfusion of decreased regions in the baseline imaging was increased in acetazolamide stress SPECT test.

Arterial Stiffness is Correlated with Cognitive Decline Independent of Silent Brain Ischemia

Arterial Stiffness is Correlated with Cognitive Decline Independent of Silent Brain Ischemia

Selective Factor XIIa Inhibition Attenuates Silent Brain Ischemia: Application of Molecular Imaging Targeting Coagulation Pathway

The purpose of this study was use molecular imaging targeting coagulation pathway and inflammation to better understand the pathophysiology of silent brain ischemia (SBI) and monitor the effects of factor XIIa inhibition. SBI can be observed in patients who undergo invasive vascular procedures. Unlike acute stroke, the diffuse nature of SBI and its less tangible clinical symptoms make this disease difficult to diagnose and treat. We induced SBI in mice by intra-arterial injection of fluorescently labeled microbeads or fractionated clot into the carotid artery. After SBI induction, diffusion-weighted magnetic resonance imaging was performed to confirm the presence of microinfarcts in asymptomatic mice. Molecular imaging targeting the downstream factor XIII activity (single-photon emission computed tomography/computed tomography) at 3 h and myeloperoxidase activity (magnetic resonance imaging) on day 3 after SBI induction were performed, without and with the intravenous administration of a recombinant selective factor XIIa inhibitor derived from the hematophagous insect Triatoma infestans (rHA-Infestin-4). Statistical comparisons between 2 groups were evaluated by the Student t test or Mann-Whitney U test. In SBI-induced mice, we found abnormal activation of the coagulation cascade (factor XIII activity) and increased inflammation (myeloperoxidase activity) close to where emboli lodge in the brain. rHA-Infestin-4 administration significantly reduced ischemic damage (53% to 85% reduction of infarct volume, p < 0.05) and pathological coagulation (35% to 39% reduction of factor XIII activity, p < 0.05) without increasing hemorrhagic frequency. Myeloperoxidase activity, when normalized to the infarct volume, did not significantly change with rHA-Infestin-4 treatment, suggesting that this treatment does not further decrease inflammation other than that resulting from the reduction in infarct volume. Focal intracerebral clotting and inflammatory activity are part of the pathophysiology underlying SBI. Inhibiting factor XIIa with rHA-Infestin-4 may present a safe and effective treatment to decrease the morbidity of SBI.

357 RELATIONSHIP BETWEEN SERUM URIC ACID AND SILENT BRAIN ISCHEMIA IN MEN

Background: Although serum uric acid (SUA) level as well as silent brain ischemia is known to a risk factor for cardiovascular events, association between SUA and silent brain ischemia has not been fully elucidated. Methods: We evaluated the association between SUA level and deep and subcortical white matter hyperintensity (DSWMH, Fazekas grade) in 1109 stroke free participants (male 56%, age 24 - 85 years) in the registry of Okinawa general health maintenance association. Results: DSWMH was found in 34% of participants (grade 1, 10%; 2, 21%; 3, 3%, respectively). The SUA level was significantly higher in men than in women (6.5 ± 1.2 vs. 4.8 ± 1.1 mg/dl, P < 0.0001). The prevalence of DSWMH (grade 2 - 3) decreased with increasing quartiles of SUA level (1st, 27%, 2nd, 20%, 3rd, 18%, 4th, 18%; P = 0.1) in men, but increased slightly (1st, 28%, 2nd, 29%, 3rd, 32%, 4th, 32%; P = 0.8) in women. We also found negative association between SUA level and Fazekas grade (no DSWMH, 6.6 ± 1.2; grade 2, 6.3 ± 1.3; grade 3, 6.0 ± 1.2 mg/dl, P < 0.05) in men, but not in women. Conclusion: Gender difference about the relationship between SUA levels and silent brain ischemia was observed. Thus SUA may have a beneficial effect of brain ischemia in men but not in women. The prospective study to elucidate association between SUA level and brain ischemia will be needed in the future.

Microembolism, silent brain infarcts and dementia

Cognitive decline becomes more prevalent than ever in parallel with the increasing life expectancy of the population. Alzheimer' disease (AD) and cerebral vascular lesions are common in the elderly and represent, with increased age, the most frequent contributors to cognitive decline. It is now believed that these pathologies frequently coexist in the same brain. The border discriminating vascular dementia from AD is blurred and challenges our understanding of these clinical entities. Further research, at both basic and clinical levels, is mandatory in order to better understand the interactions of vascular ischemic injury and primary degenerative physiopathologies of the brain, in order to prevent and better manage patients with cognitive decline.We review recent published clinical evidence of silent brain ischemia as a contributor to cognitive decline and dementia. Microemboli, from both cardiac and vascular origins, have been shown to be associated with structural changes in the brain. The role of transcranial Doppler as an objective tool for detecting and quantifying microemboli is discussed in light of recent clinical evidence.

Central sleep apnea is associated with increased risk of ischemic stroke in the elderly

Sleep apnea/hypopnea syndrome is a well-recognized independent risk factor for stroke in middle-aged population, but controversy remains in older subjects. We examined the possible association between different respiratory parameters and risk of stroke in a prospective population-based cohort of 394 stroke-free elderly subjects. Fully overnight polysomnography was performed at baseline. Over the 6 year follow-up period, 20 ischemic strokes occurred. Differences in stroke-free survival between subjects according to central apnea index (CAI) were assessed. We just observed association with incident ischemic stroke on central sleep apnea (CSA) episodes. Obstructive sleep apnea, time passed under 90% oxygen saturation, or arousal index were not associated. The event-free survival was lowest in the highest CAI group. This association was independent of any other vascular risk factors. CSA is the specific respiratory event associated with stroke in the elderly. Additionally, CSA could be a marker of silent brain ischemia, as a sign of disturbed regulation of central respiratory mechanisms, tentatively of ischemic origin.

Clinical Interaction between Brain and Kidney in Small Vessel Disease

Patients with chronic kidney disease (CKD) are well known to have a higher prevalence of cardiovascular disease from epidemiological studies. Recently, CKD has also been shown to be related to neurological disorders, not only ischemic brain injury but also cognitive impairment. This cerebrorenal connection is considered to involve small vessel disease in both the kidney and brain, based on their hemodynamic similarities. Clinical studies suggest that markers for CKD such as estimated glomerular filtration rate (eGFR), proteinuria, and albuminuria may be helpful to predict brain small vessel disease, white matter lesions (WMLs), silent brain ischemia (SBI), and microhemorrhages. Recently, changes in the vascular system of the brain have been shown to contribute to the onset and progression of cognitive impairment, not only vascular dementia but also Alzheimer's disease. Patients with CKD are also reported to have higher risk of impaired cognitive function in the future compared with non-CKD subjects. These results indicate that CKD markers may be helpful to predict the future risk of neuronal disease.

Brain embolism is a dynamic process with variable characteristics.

Embolism is recognized today as one of the main mechanisms causing ischemic brain injury. Emboli arise from many sources and in different circumstances such as atherosclerosis of the cervicocranial arteries, fat embolism syndrome, and coronary artery bypass graft surgery. Despite its importance and frequent clinical recognition, embolism remains relatively poorly understood, and its characteristics and effects on brain perfusion often are unknown. In addition, the intravascular process in brain embolism remains poorly imaged. The main historical reason for this relative paucity of knowledge was the lack of technologies that enabled detection of emboli in vivo, and assessment of their effects on the brain. This review focuses on the intravascular process of brain embolism rather than its effects on brain tissue. Based on data from selected techniques and clinical observations, it presents evidence that brain embolism is a dynamic process with some characteristics that can be assessed. Clinical experience often leaves physicians with the impression that brain embolism is a one-time event. If a patient presents to the emergency room with a sudden and focal neurologic deficit and atrial fibrillation, “embolus to the middle cerebral artery stem” is often diagnosed and is supported by neuroimaging data. Although a one-time event may very well be the pattern of embolism underlying a specific brain ischemic incident, symptomatic events may represent only the “tip of the iceberg.” Asymptomatic embolism occurs frequently between symptomatic events and often does not lead to clinically recognized or silent brain ischemia. Data from several fields of cerebrovascular research support the concept that embolism is a dynamic process with asymptomatic and symptomatic events. ### Asymptomatic retinal embolism. Asymptomatic embolism is often detected in arteries of the retinal circulation during routine funduscopic examination. Emboli composed of cholesterol, platelet-fibrin, calcium and other materials can be seen on funduscopic examination in 1.4% of the general population.1 …