Silent cerebral microbleeds associated with arterial stiffness in an apparently healthy subject

Association between pulse wave velocity and cerebral microbleeds: a systematic review and meta-analysis

Cerebral microbleeds are associated with events that are among the highest mortality and disability events combined worldwide, as well as with hypertensive vasculopathy. The aim of the present study was to investigate the relationship between a marker of hypertensive vasculopathy, arterial stiffness assessed by pulse wave velocity, and cerebral microbleeds. A systematic review and meta-analysis was performed using PubMed, Scopus, and Web of Science, according to the Meta-analysis of Observational Studies in Epidemiology (MOOSE) and Cochrane Collaboration Handbook statements. Data extraction, quality assessment and statistical analyses were performed following pre-established criteria. Twenty-one studies involving 18,436 participants were included. Higher levels of pulse wave velocity were associated with a higher presence of cerebral microbleeds p-OR = 1.26 (95% CI; 1.09-1.45), with considerable heterogeneity; even adjusting for potential confounding variables p-OR = 1.12 (95% CI, 1.05-1.20), with substantial heterogeneity. Only the percentage of women was related to p-OR in the adjusted model. Sensitivity analyses confirmed the robustness of our results. Adjusted models showed publication bias. Higher levels of arterial stiffness are associated with greater presence of cerebral microbleeds. This phenomenon may be caused by damage to the brain under higher blood flow loads, in turn due to age-induced reversal of the stiffness gradient between large and small vessels. As the world's population is undergoing demographic ageing, our results underline the importance of establishing pulse wave velocity as a cardiovascular marker for early screening and delaying the onset of the characteristic signs of both diseases.

A Triple Mystery of Insidious Organ Failure: Are the Lung, Kidney and Brain All Damaged by the Ageing Pulse?

This review explores the hypothesis that dementia in several forms, chronic kidney disease and idiopathic pulmonary fibrosis have a common cause in pulse-induced capillary haemorrhage. All three conditions are age-related and characterised by insidious onset, uncertainty about their cause, exacerbation by hypertension, resistance to treatment and the relentlessness of their progression. We argue that the three conditions are the clinical outcomes of damage caused by pulse-induced haemorrhage from capillaries. The damage, first detectable in mid-life, creates first mild and then severe symptoms of cognitive, renal and pulmonary dysfunction. We also review evidence that in all three organs there has developed, by young adulthood, a reserve of tissue that enables them to function well, despite the 'heartbeat by heartbeat' damage that accumulates from early mid-life; and that it is when that reserve is exhausted, typically in late age, that symptoms of organ failure emerge and progress. If this common cause can be established, a step will have been taken towards the understanding, treatment and delay of three conditions that have their beginnings in every individual and that, in those who survive other causes of death, become lethal in late age.

Framingham Stroke Risk Profile Score and White Matter Disease Progression

OBJECTIVES

To evaluate the relationship between Framingham Stroke Risk Profile (FSRP) score and rate of white matter hyperintensity (WMH) progression and cognition.

METHODS

Consecutive patients enrolled in the Mayo Clinic Florida Familial Cerebrovascular Diseases Registry (2011-2020) with 2 brain-MRI scans at least 1 year apart were included. The primary outcome was annual change in WMH volume (cm 3 /year) stratified as fast versus slow (above vs. below median). Cognition was assessed using a Mini-Mental State Exam (MMSE, 0-30). FSRP score (0 to 8) was calculated by summing the presence of age 65 years or older, smoking, systolic blood pressure greater than 130 mmHg, diabetes, coronary disease, atrial fibrillation, left ventricular hypertrophy, and antihypertensive medication use. Linear and logistic regression analyses were performed to examine the association between FSRP and WMH progression, and cognition.

RESULTS

In all, 207 patients were included, with a mean age of 60±16 y and 54.6% female. FSRP scores risk distribution was: 31.9% scored 0 to 1, 36.7% scored 2 to 3, and 31.4% scored ≥4. The baseline WMH volume was 9.6 cm 3 (IQR: 3.3-28.4 cm 3 ), and the annual rate of WMH progression was 0.9 cm3/year (IQR: 0.1 to 3.1 cm 3 /year). A higher FSRP score was associated with fast WMH progression (odds ratio, 1.45; 95% CI: 1.22-1.72; P<0.001) and a lower MMSE score (23.6 vs. 27.1; P<0.001). There was a dose-dependent relationship between higher FSRP score and fast WMH progression (odds ratios, 2.20, 4.64, 7.86, 8.03 for FSRP scores 1, 2, 3, and ≥4, respectively; trend P <0.001).

CONCLUSIONS

This study demonstrated an association between higher FSRP scores and accelerated WMH progression, as well as lower cognition.

Low Carotid Flow Pulsatility Index Correlates With the Presence of Unruptured Intracranial Aneurysms

Background

We assessed cases of incidental unruptured intracranial aneurysm (UIA) discovered on screening magnetic resonance angiography to identify hemodynamic and atherosclerotic risk factors.

Methods and Results

The data of 1376 healthy older subjects (age range, 31–91 years) without cerebro‐ or cardiovascular diseases who underwent brain magnetic resonance angiography as part of a medical checkup program at a health screening center were examined retrospectively. We looked for an increase in classical risk factors for UIAs (age, sex, hypertension, and smoking) and laboratory data related to lifestyle diseases among subjects with UIAs. Brachial‐ankle pulse wave velocity, central systolic blood pressure, radial augmentation index, and carotid flow pulsatility index were also compared between those with and without UIAs. We found UIAs in 79 (5.7%) of the subjects. Mean age was 67.1±9.0 years, and 55 (70%) were women. Of the 79 aneurysms, 75 (95%) were in the anterior circulation, with a mean diameter of 3.1 mm (range, 2.0–8.0 mm). Subjects with UIAs were significantly older and had more severe hypertension. The carotid flow pulsatility index was significantly lower in subjects with UIAs and negatively and independently correlated with UIAs. Tertile analysis stratified by carotid flow pulsatility index revealed that subjects with lower indices had higher levels of low‐density lipoprotein cholesterol.

Conclusions

The presence of UIAs correlated with lower carotid flow pulsatility index and elevated low‐density lipoprotein cholesterol in the data from a population of healthy older volunteers. A reduced carotid flow pulsatility index may affect low‐density lipoprotein cholesterol elevation by some molecular pathways and influence the development of cerebral aneurysms. This may guide aneurysm screening indications for institutions where magnetic resonance angiography is not routine.

Exosome miR-501-3p Elevation Contributes to Progression of Vascular Stiffness

Background: Tight junction (TJ) disruption and dysfunction are involved in the progression of arteriosclerosis. miR-501-3p regulates endothelial TJ protein-1, resulting in TJ disruption. Because exosomal microRNAs can travel to distant tissues and influence cell behavior, patients with elevated miR-501-3p may experience accelerated vascular disease progression secondary to miR-501-3p-induced reductions in TJ. This study investigated whether plasma exosome miR-501-3p levels are associated with vascular stiffness, an indicator for arteriosclerotic changes. Methods and Results: Fifty-one subjects (mean [±SD] age 70±8 years, 37% male) enrolled in a medical checkup program were recruited to the study. Brachial-ankle arterial pulse wave velocity (baPWV) and plasma exosome miR-501-3p expression were measured. Patients were divided into 2 groups depending on whether their miR-501-3p ∆C_t values were above ("High"; n=24) or below ("Low"; n=27) the cut-off levels determined by receiver operating characteristic (ROC) curve analysis. Median (interquartile range) baPWV levels were significantly higher in the miR-501-3p High than Low group (1,664 [1,496-1,859] vs. 1,450 [1,353-1,686] cm/s, respectively; P<0.05). Multivariate logistic regression analysis showed a significant association between increased baPWV and High miR-501-3p expression (odds ratio 4.66). At follow-up visits (mean 62 months later), baPWV remained significantly higher in the miR-501-3p High than Low group (1,830 [1,624-2,056] vs. 1,620 [1,377-1,816] cm/s, respectively; P<0.05). Conclusions: High expression levels of exosome miR-501-3p contribute to arteriosclerotic changes.

Brachial-Ankle Pulse Wave Velocity is Related to the Total Cerebral Small-Vessel Disease Score in an Apparently Healthy Asymptomatic Population

INTRODUCTION

Cerebral small-vessel disease (CSVD) is an extensive cerebrovascular disease associated with many poor outcomes. Previous studies have shown that brachial-ankle pulse wave velocity (baPWV) is related to various neuroimaging signatures, but its association with the total CSVD burden remains unknown. We aimed to explore whether baPWV is related to the total CSVD score and to establish a cutoff for detecting the presence and severity of CSVD, which may guide clinical preventive measures.

METHODS

We retrospectively selected 684 neurologically healthy participants to explore correlations between baPWV and the total CSVD score and each of its components (lacunes, white matter hyperintensity (WMH), perivascular space (PVS), and cerebral microbleeds (CMBs)). Subsequently, we established two receiver operating characteristic (ROC) curves to study the effectiveness of baPWV in predicting CSVD (scores 1-4) and severe CSVD (scores 3-4).

RESULTS

The median baPWV was 13.16 m/s, which increased significantly with increasing scores (0-4). BaPWV was significantly higher among persons with each component of the total CSVD score than among those without any components. Multivariable ordinal logistic regression analyses showed that a one-unit (m/s) change in baPWV significantly increased the total CSVD score by 0.012. The optimal baPWV cutoffs for detecting CSVD and severe CSVD were 13.12 m/s and 15.63 m/s, respectively.

CONCLUSIONS

BaPWV was positively correlated with the total CSVD score, suggesting that baPWV measurement is a useful method for early diagnosis of CSVD, which may contribute to preventing and controlling CSVD progression in the general population of China.

CT imaging features of carotid artery plaque vulnerability

Despite steady advances in medical care, cardiovascular disease remains one of the main causes of death and long-term morbidity worldwide. Up to 30% of strokes are associated with the presence of carotid atherosclerotic plaques. While the degree of stenosis has long been recognized as the main guiding factor in risk stratification and therapeutical decisions, recent evidence suggests that features of unstable, or ‘vulnerable’, plaques offer better prognostication capabilities. This paradigmatic shift has motivated researchers to explore the potentialities of non-invasive diagnostic tools to image not only the lumen, but also the vascular wall and the structural characteristics of the plaque. The present review will offer a panoramic on the imaging modalities currently available to characterize carotid atherosclerotic plaques and, in particular, it will focus on the increasingly important role covered by multidetector computed tomographic angiography.

Adverse Vascular Risk Relates to Cerebrospinal Fluid Biomarker Evidence of Axonal Injury in the Presence of Alzheimer's Disease Pathology

BACKGROUND

Vascular risk factors promote cerebral small vessel disease and neuropathological changes, particularly in white matter where large-caliber axons are located. How Alzheimer's disease pathology influences the brain's vulnerability in this regard is not well understood.

OBJECTIVE

Systemic vascular risk was assessed in relation to cerebrospinal fluid concentrations of neurofilament light, a biomarker of large-caliber axonal injury, evaluating for interactions by clinical and protein markers of Alzheimer's disease.

METHODS

Among Alzheimer's Disease Neuroimaging Initiative participants with normal cognition (n = 117), mild cognitive impairment (n = 190), and Alzheimer's disease (n = 95), linear regression related vascular risk (as measured by the modified Framingham Stroke Risk Profile) to neurofilament light, adjusting for age, sex, education, and cognitive diagnosis. Interactions were assessed by cognitive diagnosis, and by cerebrospinal fluid markers of Aβ42, hyperphosphorylated tau, and total tau.

RESULTS

Vascular risk and neurofilament light were not related in the main effect model (p = 0.08). However, interactions emerged for total tau (p = 0.01) and hyperphosphorylated tau (p = 0.002) reflecting vascular risk becoming more associated with cerebrospinal fluid neurofilament light in the context of greater concentrations of tau biomarkers. An interaction also emerged for the Alzheimer's disease biomarker profiles (p = 0.046) where in comparison to the referent 'normal' biomarker group, individuals with abnormal levels of both Aβ42 and total tau showed stronger associations between vascular risk and neurofilament light.

CONCLUSION

Older adults may be more vulnerable to axonal injury in response to higher vascular risk burdens in the context of concomitant Alzheimer's disease pathology.

Lipid levels and the risk of hemorrhagic stroke among women

OBJECTIVE

To examine the association between lipid levels and hemorrhagic stroke risk among women.

METHODS

We performed a prospective cohort study among 27,937 women enrolled in the Women's Health Study with measured total cholesterol, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C), as well as triglycerides. Strokes were confirmed by medical record review. We used Cox proportional hazards models to analyze associations between lipid categories and hemorrhagic stroke risk.

RESULTS

During a mean of 19.3 years of follow-up, 137 hemorrhagic strokes occurred. Compared to those with LDL-C levels 100-129.9 mg/dL, after multivariable adjustment, those with LDL-C levels <70 mg/dL had 2.17 times the risk (95% confidence interval [CI] 1.05, 4.48) of experiencing a hemorrhagic stroke. No significant increase in risk was seen for those with LDL-C levels 130-159.9 mg/dL (relative risk [RR] 1.14; 95% CI 0.72, 1.80) or 70-99.9 mg/dL (RR 1.25; 95% CI 0.76, 2.04). There was a suggestion, although not significant, of increased risk for those with LDL-C levels ≥160 mg/dL (RR 1.53; 95% CI 0.92, 2.52). Women in the lowest quartile of triglycerides had a significantly increased risk of hemorrhagic stroke compared to women in the top quartile after multivariable adjustment (RR 2.00; 95% CI 1.18, 3.39). We observed no significant associations between total cholesterol or HDL-C levels and hemorrhagic stroke risk.

CONCLUSION

LDL-C levels <70 mg/dL and low triglyceride levels were associated with increased risk of hemorrhagic stroke among women.

Pulse Wave Velocity in Atherosclerosis

Early detection of subclinical atherosclerosis is important to reduce patients' cardiovascular risk. However, current diagnostic strategy focusing on traditional risk factors or using risk scoring is not satisfactory. Non-invasive imaging tools also have limitations such as cost, time, radiation hazard, renal toxicity, and requirement for specialized techniques or instruments. There is a close interaction between arterial stiffness and atherosclerosis. Increased luminal pressure and shear stress by arterial stiffening causes endothelial dysfunction, accelerates the formation of atheroma, and stimulates excessive collagen production and deposition in the arterial wall, leading to the progression of atherosclerosis. Pulse wave velocity (PWV), the most widely used measure of arterial stiffness, has emerged as a useful tool for the diagnosis and risk stratification of cardiovascular disease (CVD). The measurement of PWV is simple, non-invasive, and reproducible. There have been many clinical studies and meta-analyses showing the association between PWV and coronary/cerebral/carotid atherosclerosis. More importantly, longitudinal studies have shown that PWV is a significant risk factor for future CVD independent of well-known cardiovascular risk factors. The measurement of PWV may be a useful tool to select subjects at high risk of developing subclinical atherosclerosis or CVD especially in mass screening.

Pulse Wave Velocity in Atherosclerosis

Early detection of subclinical atherosclerosis is important to reduce patients' cardiovascular risk. However, current diagnostic strategy focusing on traditional risk factors or using risk scoring is not satisfactory. Non-invasive imaging tools also have limitations such as cost, time, radiation hazard, renal toxicity, and requirement for specialized techniques or instruments. There is a close interaction between arterial stiffness and atherosclerosis. Increased luminal pressure and shear stress by arterial stiffening causes endothelial dysfunction, accelerates the formation of atheroma, and stimulates excessive collagen production and deposition in the arterial wall, leading to the progression of atherosclerosis. Pulse wave velocity (PWV), the most widely used measure of arterial stiffness, has emerged as a useful tool for the diagnosis and risk stratification of cardiovascular disease (CVD). The measurement of PWV is simple, non-invasive, and reproducible. There have been many clinical studies and meta-analyses showing the association between PWV and coronary/cerebral/carotid atherosclerosis. More importantly, longitudinal studies have shown that PWV is a significant risk factor for future CVD independent of well-known cardiovascular risk factors. The measurement of PWV may be a useful tool to select subjects at high risk of developing subclinical atherosclerosis or CVD especially in mass screening.

Distribution of cerebral microbleeds in the East and West: Individual participant meta-analysis

OBJECTIVE

We investigated differences in the anatomical distribution of cerebral microbleeds (CMBs) on MRI, hypothesized to indicate the type of underlying cerebral small vessel disease (SVD), between Eastern and Western general populations.

METHODS

We analyzed data from 11 studies identified by a PubMed search between 1996 and April 2014 according to the Preferred Reporting Items for a Systematic Review and Meta-analysis of Individual Participant Data. Study quality measures indicated low or medium risk of bias. We included stroke-free participants from populations aged between 55 and 75 years, categorized by geographic location (Eastern or Western). We categorized CMB distribution (strictly lobar, deep and/or infratentorial [D/I], or mixed [i.e., CMBs located in both lobar and D/I regions]). We tested the hypothesis that Eastern and Western populations have different anatomical distributions of CMBs using multivariable mixed effects logistic regression analyses adjusted for age, sex, and hypertension and clustering by institution.

RESULTS

Among 8,595 stroke-free individuals (mean age [SD] 66.7 [5.6] years; 48% male; 42% from a Western population), 624 (7.3%) had CMBs (strictly lobar in 3.1%; D/I or mixed in 4.2%). In multivariable mixed effects models, Eastern populations had higher odds of D/I or mixed CMBs (adjusted odds ratio 2.78, 95% confidence interval [CI] 1.77-4.35) compared to Western populations. Eastern populations had a higher number of D/I or mixed CMBs (adjusted prevalence ratio 2.83, 95% CI 1.27-6.31).

CONCLUSIONS

Eastern and Western general populations have different anatomical distributions of CMBs, suggesting differences in the spectrum of predominant underlying SVDs, with potential implications for SVD diagnosis and treatment.

Arterial Stiffness and Cerebral Small Vessel Disease

Background and Objective: Studies on relations between arterial stiffness and full spectrum of radiological features of cerebral small vessel disease (CSVD) are scarce. We aim to investigate the association of arterial stiffness with lacunes, white matter hyperintensities (WMH), microbleeds (CMBs), dilated perivascular spaces (PVS), and brain atrophy in a community-based sample.

Methods: A total of 953 participants (55.7 ± 9.4 years) who underwent brachial-ankle pulse wave velocity (baPWV) and brain magnetic resonance imaging were included. Lacunes, CMBs, and PVS were visually rated. Brain structure and WMH were automatically segmented. Brain parenchyma fraction (BPF), a surrogate index of brain atrophy, was calculated as a ratio of brain parenchyma volume to total intracranial volume. Multivariable logistic and linear regressions were used to investigate the associations between baPWV and CSVD. Subsequently, we explored these associations in strata of age.

Results: Increased baPWV was associated with severe PVS in white matter (OR, 1.09; 95%CI, 1.01–1.17; p = 0.022), larger WMH volume (β, 0.08; 95%CI, 0.04–0.12; p < 0.001), lower BPF (β, −0.09; 95%CI, −0.15– −0.03; p = 0.007), and marginally associated with strictly lobar CMBs (OR, 1.11; 95%CI, 1.00–1.23; p = 0.055), but not with lacunes. WMH volume mediated the relation between baPWV and BPF. In age subgroup analysis, the association of baPWV with PVS in white matter was stronger among those aged <55 years, whereas the association with brain atrophy was more prominent among those aged ≥55 years. Increased baPWV was associated with larger WMH volume in both younger and older individuals.

Conclusions: Increased arterial stiffness was associated with most of imaging markers of CSVD, including PVS in white matter, larger WMH volume, strictly lobar CMBs, and brain atrophy, but not lacunes. The mechanisms underlying these associations and their potential clinical significances warrant further investigations.

Framingham Stroke Risk Profile is related to cerebral small vessel disease progression and lower cognitive performance in patients with hypertension

The Framingham Stroke Risk Profile (FSRP) was developed to predict clinical stroke. We investigated if FSRP is associated with more "silent" effects of cerebrovascular disease, namely progression of cerebral small vessel disease (cSVD)-related brain damage and cognitive performance in hypertensive patients. Ninety patients with essential hypertension underwent a brain MRI scan and FSRP assessment at baseline, and a second brain MRI scan and neuropsychological assessment at 9-year follow-up. We visually rated progression of cSVD-related MRI markers. FSRP was associated with progressive periventricular white matter hyperintensities (P = .017) and new microbleeds (P = .031), but not after correction for the FSRP age component. FSRP was associated with lower overall cognitive performance (P < .001) and this remained significant after correction for the FSRP age component. A vascular risk score might be useful in predicting progression of cSVD-related brain damage or future cognitive performance in hypertensive patients. Age seems to be the most important component in FSRP.

Tumor Necrosis Factor Receptor 1 and 2 Are Associated With Risk of Intracerebral Hemorrhage

BACKGROUND AND PURPOSE

Raised plasma concentrations of tumor necrosis factor receptors (TNFR) have been linked to arterial stiffness, cerebral microbleeds, and vascular events. The aim of this study was to investigate the association of circulating levels of TNFR1 and TNFR2 with risk for future intracerebral hemorrhage (ICH).

METHODS

The population-based MDCS cohort (Malmö Diet and Cancer Study; n=28 449) was conducted in 1991 to 1996. A nested case-control study was performed in the MDCS, including 220 cases who experienced ICH during the follow-up period (mean age at inclusion 62 years, 48% men) and 244 matched controls. Of the 220 ICH cases, 68 died within 28 days. Conditional logistic regression was used to study the association between plasma levels of TNFR1 and TNFR2 and incident ICH, adjusting for known ICH risk factors.

RESULTS

Concentrations of both TNFR1 and TNFR2 were significantly higher in subjects who developed ICH during the follow-up. The associations remained after adjustment for ICH risk factors (TNFR1: odds ratio [OR], 2.28; 95% confidence interval [CI], 1.26-4.11; P=0.006; TNFR2: OR, 1.77; CI, 1.16-2.70; P=0.008). ORs were somewhat higher for nonlobar ICH (3.04; CI, 1.29-7.14 and 2.39; CI, 1.32-4.32, respectively) than for lobar ICH (2.03; CI, 0.93-4.41 and 1.35; CI, 0.78-2.37, respectively). TNFR1 and TNFR2 were also associated with increased risk of fatal ICH (TNFR1: OR, 4.42; CI, 1.67-11.6; TNFR2: OR, 2.90; CI, 1.50-5.58) and with poor functional outcome according to the modified Rankin Scale.

CONCLUSIONS

High plasma levels of TNFR1 and TNFR2 were associated with incident ICH, most clearly with ICH of nonlobar location. The results suggest that tumor necrosis factor-mediated inflammation could be associated with vascular changes preceding ICH.

Recent Progress in Vascular Aging: Mechanisms and Its Role in Age-related Diseases

As with many age-related diseases including vascular dysfunction, age is considered an independent and crucial risk factor. Complicated alterations of structure and function in the vasculature are linked with aging hence, understanding the underlying mechanisms of age-induced vascular pathophysiological changes holds possibilities for developing clinical diagnostic methods and new therapeutic strategies. Here, we discuss the underlying molecular mediators that could be involved in vascular aging, e.g., the renin-angiotensin system and pro-inflammatory factors, metalloproteinases, calpain-1, monocyte chemoattractant protein-1 (MCP-1) and TGFβ-1 as well as the potential roles of testosterone and estrogen. We then relate all of these to clinical manifestations such as vascular dementia and stroke in addition to reviewing the existing clinical measurements and potential interventions for age-related vascular dysfunction.

Arterial Stiffness is an Independent Risk Factor for Anemia After Percutaneous Native Kidney Biopsy

BACKGROUND/AIMS

Bleeding is the most common complication after renal biopsy. Although numerous predictors of bleeding have been reported, it remains unclear whether arterial stiffness affects bleeding complications.

METHOD

We performed an observational study of the renal biopsies performed in our division over an approximately 6-year period (May 2010 to May 2016). The clinical and laboratory factors were analyzed to reveal the risk factors associated with bleeding, with a focus on anemia (defined as a ≥10% decrease in hemoglobin [Hb] after biopsy). The brachial-ankle pulse wave velocity (baPWV) was measured to evaluate arterial stiffness.

RESULTS

This study included 462 patients (male, n=244; female, n=218). Anemia (defined above) was observed in 54 patients (11.7%). The risk of anemia was higher in women, older patients, and patients with lower serum albumin, lower eGFR and lower diastolic blood pressure after biopsy. We then performed a further analysis of 187 patients whose baPWV data were available. Multivariate analysis revealed that a higher baPWV was an independent risk factor for anemia. ROC analysis for predicting anemia found that a baPWV value of 1839 cm/s had the best performance (AUC 0.689).

CONCLUSION

An increased baPWV may be a more valuable predictor of bleeding than any of the other reported risk factors.

Association between large artery atherosclerosis and cerebral microbleeds: a systematic review and meta-analysis

OBJECTIVE

The aim of this systematic review and meta-analysis was to provide evidence that biomarkers of large artery atherosclerosis, including arterial stenosis and greater carotid intima-media thickness (cIMT), may serve as clinical markers of subclinical haemorrhage-prone cerebral small vessel disease, reflected by cerebral microbleeds (CMBs).

METHODS

We searched PubMed, MEDLINE, Web of Science, EMBASE and the Cochrane Library to identify relevant studies published before 1 July 2016. The association between arterial stenosis and CMBs was estimated by the OR and 95% CI. The association of cIMT and CMBs was calculated using the standardised mean difference (SMD). Heterogeneity and publication bias were explored.

RESULTS

8 studies including a total of 7160 participants were pooled in the meta-analysis. 6 of the included studies were cross-sectional, except that 2 were prospective. We found a significant association between arterial stenosis >50% and the presence of CMBs (OR 1.95, 95% CI 1.13 to 3.36, I²=56.1%). A fixed-effects model suggested that patients with CMBs were more likely to have a greater cIMT (SMD 0.20, 95% CI 0.11 to 0.28, I²=24.7%).

CONCLUSIONS

This systematic review and meta-analysis found that there is a relationship between large artery atherosclerosis and CMBs. Future studies are needed to confirm the impact of atherosclerosis on the CMBs, which may have potential therapeutic implications.

Oral Cnm-positive Streptococcus Mutans Expressing Collagen Binding Activity is a Risk Factor for Cerebral Microbleeds and Cognitive Impairment

Cerebral microbleeds (CMBs) are an important risk factor for stroke and dementia. We have shown that the collagen binding surface Cnm protein expressed on cnm-positive Streptococcus mutans is involved in the development of CMBs. However, whether the collagen binding activity of cnm-positive S. mutans is related to the nature of the CMBs or to cognitive impairment is unclear. Two-hundred seventy nine community residents (70.0 years) were examined for the presence or absence of cnm-positive S. mutans in the saliva by PCR and collagen binding activity, CMBs, and cognitive function were evaluated. Cnm-positive S. mutans was detected more often among subjects with CMBs (p < 0.01) than those without. The risk of CMBs was significantly higher (odds ratio = 14.3) in the group with S. mutans expressing collagen binding activity, as compared to the group without that finding. Deep CMBs were more frequent (67%) and cognitive function was lower among subjects with cnm-positive S. mutans expressing collagen binding activity. This work supports the role of oral health in stroke and dementia and proposes a molecular mechanism for the interaction.

Relationship between asymptomatic intra-cranial lesions and brachial-ankle pulse wave velocity in coronary artery disease patients without stroke

Little is known about the significance of asymptomatic intra-cranial lesions (ICL) identified by brain MRI in coronary artery disease (CAD) patients. Silent cerebral lesions are suggested to be associated with arterial stiffness in healthy subjects. We investigated whether subclinical ICL are associated with arterial stiffness and the prognosis in CAD patients without medical history of cerebrovascular diseases. We recruited CAD patients who required percutaneous coronary intervention (PCI), did not meet exclusion criteria, and agreed with MRI before PCI. Subjects were divided into two groups according to the presence of ICL of cerebral microbleeds or lacunar infarction. Arterial stiffness was evaluated by brachial-ankle pulse wave velocity (baPWV). Clinical outcome was defined as a composite of cardiovascular death, non-fatal myocardial infarction, stroke, unstable angina and heart failure. In total, 149 patients underwent brain MRI. Patients with ICL (n=55) had significantly higher baPWV than those without ICL (1591-2204 vs. 1450-1956 cm per sec; P=0.009). A multivariate analysis showed that male sex (odds ratio (OR), 3.15; 95% confidence interval (CI), 1.38-7.20; P=0.006) and baPWV (OR, 1.001; 95% CI, 1.000-1.002; P=0.023) were predictors of ICL. In total, 12 patients experienced a cardiovascular event. The Kaplan-Meier analysis indicated a significantly higher incidence of cardiovascular events in patients with ICL (log-rank test: P=0.018). Multivariate Cox proportional hazards analyses indicated that ICL finding was a significant predictor of clinical outcome (hazard ratio, 3.41; 95% CI, 1.02-11.5; P=0.047). Patients with subclinical ICL had a higher baPWV and worse prognoses than those without ICL.

Safety of Antithrombotic Agents in Elderly Patients with Acute Coronary Syndromes

There are unique challenges in the treatment and prevention of acute coronary syndromes (ACS) with antithrombotics in elderly patients: elderly patients usually require multiple drugs due to comorbidities, are highly susceptible to adverse drug reactions and drug-drug interactions, may have cognitive problems affecting compliance and complications, are especially exposed to the risk of falls and, most importantly, ageing is an independent risk factor for bleeding. Antithrombotic drugs, alone or in association, further and variously amplify age-related bleeding risk. Moreover, age-related changes in primary haemostasis may potentially affect the pharmacodynamics of some antiplatelet drugs. Thus, elderly subjects might be more or less sensitive to standard antiplatelet regimens depending on individual characteristics affecting antiplatelet drug response. Importantly, elderly patients are a rapidly growing population worldwide, have the highest incidence of ACS, but are poorly represented in clinical trials. As a consequence, evidence on antithrombotic drug benefits and risks is limited. Thus, in the real-world setting, older people are often denied antithrombotic drugs because of unjustified concerns, or might be over-treated and exposed to excessive bleeding risk. Personalized antithrombotic therapy in elderly patients is particularly critical, to minimize risks without affecting efficacy.

Baseline platelet indices and bleeding after transcatheter aortic valve implantation

Bleeding complications are frequent and independently predict mortality after transcatheter aortic valve implantation (TAVI). It has been demonstrated that certain platelet parameters are indicative of platelet reactivity. We sought to determine the possible correlation between simple platelet indices and bleeding complications in patients undergoing TAVI. Platelet indices--platelet count, mean platelet volume (MPV), platelet distribution width and plateletcrit--were measured in 110 consecutive patients on the day preceding TAVI. In-hospital bleeding events after TAVI were assessed according to the Valve Academic Research Consortium-2 classification as any bleeding, major and life-threatening bleeding (MLTB) and need for transfusion. By receiver-operating characteristic analysis, only MPV was able to distinguish between patients with and without any bleeding [area under the curve (AUC) 0.629, 95% confidence interval (CI) 0.531-0.719, P = 0.0342], MLTB (AUC 0.730, 95% CI 0.637-0.811, P = 0.0004) and need for transfusion (AUC 0.660, 95% CI 0.563-0.747, P = 0.0045). By multivariate logistic regression, high MPV (>10.6) and low platelet distribution width (<14.8) were associated with increased risk of any bleeding [odds ratio (OR) 4.08, 95% CI 1.66-10.07, P = 0.0022; and OR 3.82, 95% CI 1.41-10.36, P = 0.0084, respectively] and MLTB (OR 10.76, 95% CI 3.05-38, P = 0.0002; and OR 8.46, 95% CI 1.69-42.17, P = 0.0092, respectively). Additionally, high MPV independently correlated with the need for transfusion (OR 4.11, 95% CI 1.71-9.86, P = 0.0016). Larger and less heterogenic platelets may be associated with increased risk of short-term bleeding complications after TAVI.

Association between Helicobacter pylori Infection and Cerebral Small Vessel Disease

Background

Small vessel disease is an important cause of cerebrovascular diseases and cognitive impairment in the elderly. There have been conflicting results regarding the relationship between Helicobacter pylori infection and ischemic stroke. This study aimed to examine the association between H. pylori infection and cerebral small vessel disease.

Methods

The study included 1,117 patients who underwent brain magnetic resonance imaging and H. pylori identification between 2005 and 2013 at Health Promotion Center, Seoul National University Hospital. Multivariable logistic regression analysis was used to assess the association between H. pylori infection and small vessel disease with adjustment for age, sex, hypertension, diabetes mellitus, dyslipidemia, body mass index, smoking status, problem drinking, and antiplatelet use.

Results

The adjusted odds ratios (aORs) for the association between H. pylori infection and silent brain infarction and cerebral microbleeds were 1.03 (95% confidence interval [CI], 0.66-1.61) and 0.70 (95% CI, 0.38-1.28), respectively. The aORs for silent brain infarction and cerebral microbleeds were 0.81 (95% CI, 0.44-1.44) and 0.59 (95% CI, 0.30-1.18) in patients aged <65 years and 1.59 (95% CI, 0.78-3.22) and 1.89 (95% CI, 0.38-9.33) in those aged >65 years, respectively. Moreover, the aORs for silent brain infarction and cerebral microbleeds were 0.96 (95% CI, 0.54-1.71) and 0.74 (95% CI, 0.33-1.69) in H. pylori-infected patients without atrophic gastritis and 0.89 (95% CI, 0.48-1.62) and 0.99 (95% CI, 0.43-2.27) in those with atrophic gastritis, respectively.

Conclusion

No association between H. pylori infection and small vessel disease was observed. H. pylori-induced inflammation may not be a risk factor for microcirculatory damage in the brain.

Carotid arterial stiffness and risk of incident cerebral microbleeds in older people: the Age, Gene/Environment Susceptibility (AGES)-Reykjavik study

OBJECTIVE

Age and high blood pressure are major risk factors for cerebral microbleeds (CMBs). However, the underlying mechanisms remain unclear and arterial stiffness may be important. We investigated whether carotid arterial stiffness is associated with incidence and location of CMBs.

APPROACH AND RESULTS

In the prospective, population-based Age, Gene/Environment Susceptibility (AGES)-Reykjavik study, 2512 participants aged 66 to 93 years underwent a baseline brain MRI examination and carotid ultrasound in 2002 to 2006 and returned for a repeat brain MRI in 2007 to 2011. Common carotid arterial stiffness was assessed using a standardized protocol and expressed as carotid arterial strain, distensibility coefficient, and Young elastic modulus. Modified Poisson regression was applied to relate carotid arterial stiffness parameters to CMB incidence. During a mean follow-up of 5.2 years, 463 people (18.4%) developed new CMBs, of whom 292 had CMBs restricted to lobar regions and 171 had CMBs in a deep or infratentorial region. After adjusting for age, sex, and follow-up interval, arterial stiffness measures were associated with incident CMBs (risk ratio per SD decrease in carotid arterial strain, 1.11 [95% confidence interval, 1.01-1.21]; per SD decrease in natural log-transformed distensibility coefficient, 1.14 [1.05-1.24]; and per SD increase in natural log-transformed Young elastic modulus, 1.13 [1.04-1.23]). These measures were also significantly associated with incident deep CMBs (1.18 [1.02-1.37]; 1.24 [1.08-1.42]; and 1.23 [1.07-1.42]) but not with lobar CMBs. When further adjusted for blood pressure and other baseline vascular risk factors, carotid plaque, prevalent CMBs, subcortical infarcts, and white matter hyperintensities, the associations persisted.

CONCLUSIONS

Our findings support the hypothesis that localized increases in carotid arterial stiffness may contribute to the development of CMBs, especially in a deep location attributable to hypertension.

Cerebral Microbleeds and White Matter Hyperintensities in Cognitively Healthy Elderly: A Cross-Sectional Cohort Study Evaluating the Effect of Arterial Stiffness

BACKGROUND

Arterial stiffness reflects the ageing processes in the vascular system, and studies have shown an association between reduced cognitive function and cerebral small vessel disease. Small vessel disease can be visualized as white matter hyperintensities (WMH) and lacunar infarcts but also as cerebral microbleeds on brain magnetic resonance imaging (MRI). We aimed to investigate if arterial stiffness influences the presence of microbleeds, WMH and cognitive function in a population of cognitively healthy elderly.

METHODS

The study population is part of the Swedish BioFinder study and consisted of 208 individuals without any symptoms of cognitive impairment, who scored >27 points on the Mini-Mental State Examination. The participants (mean age, 72 years; 59% women) underwent MRI of the brain with visual rating of microbleeds and WMH. Arterial stiffness was measured with carotid-femoral pulse wave velocity (cfPWV). Eight cognitive tests covering different cognitive domains were performed.

RESULTS

Microbleeds were detected in 12% and WMH in 31% of the participants. Mean (±standard deviation, SD) cfPWV was 10.0 (±2.0) m/s. There was no association between the presence of microbleeds and arterial stiffness. There was a positive association between arterial stiffness and WMH independent of age or sex (odds ratio, 1.58; 95% confidence interval, 1.04-2.40, p < 0.05), but the effect was attenuated when further adjustments for several cardiovascular risk factors were performed (p > 0.05). Cognitive performance was not associated with microbleeds, but individuals with WMH performed slightly worse than those without WMH on the Symbol Digit Modalities Test (mean ± SD, 35 ± 7.8 vs. 39 ± 8.1, p < 0.05). Linear regression revealed no direct associations between arterial stiffness and the results of the cognitive tests.

CONCLUSIONS

Arterial stiffness was not associated with the presence of cerebral microbleeds or cognitive function in cognitively healthy elderly. However, arterial stiffness was related to the presence of WMH, but the association was attenuated when multiple adjustments were made. There was a weak negative association between WMH and performance in one specific test of attention. Longitudinal follow-up studies are needed to further assess the associations.

Association of postural instability with asymptomatic cerebrovascular damage and cognitive decline: the Japan Shimanami health promoting program study

BACKGROUND AND PURPOSE

Asymptomatic cerebral small-vessel disease (cSVD) in elderly individuals are potent risk factors for stroke. In addition to common clinical risk factors, postural instability has been postulated to be associated with cSVD in older frail patients. Here, we conducted a cross-sectional study to understand the possible link between postural instability and asymptomatic cSVD further, namely periventricular hyperintensity, lacunar infarction, and microbleeds, as well as cognitive function, in a middle-aged to elderly general population (n=1387).

METHODS

Postural instability was assessed based on one-leg standing time (OLST) and posturography findings. cSVD was evaluated by brain MRI. Mild cognitive impairment was assessed using a computer-based questionnaire, and carotid intima-media thickness as an index of atherosclerosis was measured via ultrasonography.

RESULTS

Frequency of short OLST, in particular <20 s, increased linearly with severity of cSVD (lacunar infarction lesion: none, 9.7%; 1, 16.0%; >2, 34.5%; microbleeds lesion: none, 10.1%; 1, 15.3%; >2, 30.0%; periventricular hyperintensity grade: 0, 5.7%; 1, 11.5%; >2, 23.7%). The association of short OLST with lacunar infarction and microbleeds but not periventricular hyperintensity remained significant even after adjustment for possible covariates (lacunar infarction, P=0.009; microbleeds, P=0.003; periventricular hyperintensity, P=0.601). In contrast, no significant association was found between posturographic parameters and cSVD, whereas these parameters were linearly associated with OLST. Short OLST was also significantly associated with reduced cognitive function independent of covariates, including cSVD (P=0.002).

CONCLUSIONS

Postural instability was found to be associated with early pathological changes in the brain and functional decline, even in apparently healthy subjects.

Association between arterial stiffness, cerebral small vessel disease and cognitive impairment: A systematic review and meta-analysis

Arterial stiffness may be a cause of cerebral small vessel disease and cognitive impairment. We therefore performed a systematic review and meta-analysis of studies on the association between stiffness, cerebral small vessel disease and cognitive impairment. For the associations between stiffness (i.e. carotid-femoral pulse wave velocity (cfPWV), brachial-ankle PWV (baPWV), carotid stiffness and pulse pressure) on the one hand and cerebral small vessel disease and cognitive impairment on the other, we identified 23 (n=15,666/20 cross-sectional; 1 longitudinal; 2 combined cross-sectional/longitudinal) and 41 studies (n=57,671/26 cross-sectional; 11 longitudinal; 4 combined cross-sectional/longitudinal), respectively. Pooled analyses of cross-sectional studies showed that greater stiffness was associated with markers of cerebral small vessel disease with odds ratios, per +1 SD, of 1.29-1.32 (P<.001). Studies on cognitive impairment could not be pooled due to large heterogeneity. Some (but not all) studies showed an association between greater stiffness and cognitive impairment, and the strength of this association was relatively weak. The present study supports the hypothesis that greater arterial stiffness is a contributor to microvascular brain disease.

Comparison of arteriosclerotic indicators in patients with ischemic stroke: ankle-brachial index, brachial-ankle pulse wave velocity and cardio-ankle vascular index

The ankle-brachial index (ABI), brachial-ankle pulse wave velocity (baPWV) and cardio-ankle vascular index (CAVI) are surrogate markers of arteriosclerosis. However, their roles in patients with acute ischemic stroke remain unclear. From October 2003 to September 2011, we enrolled patients with arteriosclerotic ischemic stroke (AIS) exhibiting large infarcts attributed to large-artery atherosclerosis (LAA) or deep subcortical infarcts (mainly lacunar infarcts) attributed to small-artery disease (SAD). Outpatients without a history of stroke served as controls (CTL). We divided the study period into two terms and assessed patients using two different oscillometric devices (Form PWV/ABI, Omron Colin; and VaSera VS-1500, Fukuda Denshi) in each term. One-way analysis of variance and age- and sex-adjusted analysis of covariance were used to compare the three groups. We analyzed 842 patients. The ABI was significantly lower in the LAA (n = 102) group than in the SAD (n = 280) and CTL (n = 460) groups. The baPWV was significantly higher in the LAA and SAD groups than in the CTL group. The CAVI gradually increased in the order of CTL, SAD and LAA. The cutoff values of baPWV and CAVI for detection of AIS were 18.3 m s(-1) (odds ratio (OR): 6.09, 95% confidence interval (CI): 3.97-9.62, P < 0.01) and 9.5 (OR: 1.44, 95% CI: 1.24-1.70, P < 0.001), respectively. Among the three indicators, a lower ABI indicated advanced atherosclerosis associated with LAA, and an increased baPWV more closely indicated AIS. An increased CAVI may indicate the degree of vessel stiffness due to arteriosclerosis.

Clinical associations of cerebral microbleeds on magnetic resonance neuroimaging

Susceptibility-weighted and gradient-recalled echo T2* magnetic resonance imaging have enabled the detection of very small foci of blood within the brain, which have been termed "cerebral microbleeds." These petechial intraparenchymal hemorrhages have begun to emerge as diagnostically and prognostically useful markers in a variety of disease states. Severe hypertension and cerebral amyloid angiopathy are perhaps the best established microhemorrhagic conditions from neuroimaging literature; however, many others are also recognized including cerebral autosomal dominant arteriopathy, subcortical infarcts, and leukoencephalopathy (CADASIL), moyamoya disease, fat embolism, cerebral malaria, and infective endocarditis. Microbleeds are also a common finding in the setting of trauma and stroke. The purpose of this review is to broadly describe the neuroimaging of cerebral microbleeds in a wide variety of conditions, including the differences in their appearance and distribution in different disease states. In a few situations, the presence of microbleeds may influence clinical management, and we discuss these situations in detail. The major importance of this emerging field in neuroimaging is the potential to identify microvascular pathology at an asymptomatic or minimally symptomatic stage and create a window of therapeutic opportunity.

Arterial stiffness in patients with deep and lobar intracerebral hemorrhage

Background and Purpose

Intracerebral hemorrhage (ICH) accounts for approximately 10% of stroke cases. Hypertension may play a role in the pathogenesis of ICH that occurs in the basal ganglia, thalamus, pons, and cerebellum, but not in that of lobar ICH. Hypertension contributes to decreased elasticity of arteries, thereby increasing the likelihood of rupture in response to acute elevation in intravascular pressure. This study aimed to evaluate arterial stiffness (using the arterial stiffness index [ASI]) in patients with deep (putaminal and thalamic) ICH in comparison with patients with lobar ICH.

Methods

We enrolled 64 patients (mean±SD age: 69.3±10.7 years; 47 men and 17 women) among 73 who referred consecutively to our department for intraparenchymal hemorrhage and underwent brain computed tomography (CT) and cerebral angio-CT. In all the subjects, 24-hour heart rates and blood pressures were monitored. The linear regression slope of diastolic on systolic blood pressure was assumed as a global measure of arterial compliance, and its complement (1 minus the slope), ASI, has been considered as a measure of arterial stiffness.

Results

In the patients with deep ICH, ASI was significantly higher than in the patients with lobar ICH (0.64±0.19 vs. 0.53±0.17, P=0.04).

Conclusions

Our results suggest that in deep ICH, arterial stiffening represents a possible pathogenetic factor that modifies arterial wall properties and contributes to vascular rupture in response to intravascular pressure acute elevation. Therapeutic strategies that reduce arterial stiffness may potentially lower the incidence of deep hemorrhagic stroke.

Aortic and carotid arterial stiffness and epigenetic regulator gene expression changes precede blood pressure rise in stroke-prone Dahl salt-sensitive hypertensive rats

Multiple clinical studies show that arterial stiffness, measured as pulse wave velocity (PWV), precedes hypertension and is an independent predictor of hypertension end organ diseases including stroke, cardiovascular disease and chronic kidney disease. Risk factor studies for arterial stiffness implicate age, hypertension and sodium. However, causal mechanisms linking risk factor to arterial stiffness remain to be elucidated. Here, we studied the causal relationship of arterial stiffness and hypertension in the Na-induced, stroke-prone Dahl salt-sensitive (S) hypertensive rat model, and analyzed putative molecular mechanisms. Stroke-prone and non-stroke-prone male and female rats were studied at 3- and 6-weeks of age for arterial stiffness (PWV, strain), blood pressure, vessel wall histology, and gene expression changes. Studies showed that increased left carotid and aortic arterial stiffness preceded hypertension, pulse pressure widening, and structural wall changes at the 6-week time-point. Instead, differential gene induction was detected implicating molecular-functional changes in extracellular matrix (ECM) structural constituents, modifiers, cell adhesion, and matricellular proteins, as well as in endothelial function, apoptosis balance, and epigenetic regulators. Immunostaining testing histone modifiers Ep300, HDAC3, and PRMT5 levels confirmed carotid artery-upregulation in all three layers: endothelial, smooth muscle and adventitial cells. Our study recapitulates observations in humans that given salt-sensitivity, increased Na-intake induced arterial stiffness before hypertension, increased pulse pressure, and structural vessel wall changes. Differential gene expression changes associated with arterial stiffness suggest a molecular mechanism linking sodium to full-vessel wall response affecting gene-networks involved in vascular ECM structure-function, apoptosis balance, and epigenetic regulation.

Clinical characteristics of high plasma adiponectin and high plasma leptin as risk factors for arterial stiffness and related end-organ damage

OBJECTIVE

The relationship between plasma levels of adiponectin and cardiovascular events is inconclusive. We evaluated the clinical characteristics of people with high plasma adiponectin and high plasma leptin levels.

METHODS

Thousand seven hundred participants recruited from visitors to the Anti-Aging Doc were divided into four groups by combining the bipartiles of plasma adiponectin and leptin levels in men and women separately: AL, high adiponectin and high leptin; Al, high adiponectin and low leptin; al, low adiponectin and low leptin; aL, low adiponectin and high leptin. Body composition, including visceral fat area and thigh muscle cross-sectional area (CSA), brachial-ankle pulse wave velocity (baPWV), periventricular hyperintensity, and urinary albumin excretion, were determined.

RESULTS

Twenty percent of the studied population fell within the AL group. This group had a significantly higher visceral fat area than the Al group. Thigh muscle CSA was lowest in the AL group among groups. baPWV, brain white matter lesions, and albuminuria findings in the AL group were significantly higher than those of the Al group. Multiple and logistic regression analyses with confounding parameters further confirmed that plasma adiponectin was not an independent determinant for brain and renal small vessel-related disease.

CONCLUSION

These findings suggest that the plasma level of adiponectin alone is not enough for the risk stratification of cardiovascular disease. Leptin resistance associated with skeletal muscle loss in addition to obesity may need to be addressed to identify high risk people with high plasma adiponectin levels.

Arterial Stiffness Is Associated With Carotid Intraplaque Hemorrhage in the General Population

Objective—

The relation between arterial stiffness and atherosclerosis, and specifically the influence of arterial stiffness on plaque composition, is largely unknown. In a population-based study, we investigated the association between arterial stiffness and the presence and composition of carotid atherosclerotic plaques.

Approach and Results—

Arterial stiffness was measured in 6527 participants (67.0±8.6 years) using aortic pulse wave velocity (PWV). Presence of carotid atherosclerotic plaques was assessed with ultrasound. Subsequently, 1059 subjects with carotid plaques (>2.5 mm) underwent MRI to assess plaque composition (presence of intraplaque hemorrhage, lipid, and calcification). Generalized estimation equation analyses adjusted for age, sex, mean arterial pressure, heart rate, carotid wall thickening, pulse pressure, and traditional cardiovascular risk factors were used to study the association between PWV and the presence and composition of carotid atherosclerotic plaques. In multivariable analysis, higher PWV was independently related to higher prevalence of carotid atherosclerotic plaque on ultrasound (odds ratio for highest quartile of PWV compared with lowest quartile, 1.24 [95% confidence interval, 1.02–1.51]). Furthermore, higher PWV was associated with intraplaque hemorrhage (age- and sex-adjusted odds ratio per SD increase in PWV, 1.20 [1.04–1.38] and calcification, 1.18 [1.03–1.35]), but not with lipid. After adjustment for cardiovascular risk factors, PWV remained significantly associated with intraplaque hemorrhage (1.20 [1.01–1.43]). Additional adjustment for pulse pressure did not materially affect the effect estimate (1.19 [1.00–1.42]).

Conclusions—

Higher PWV is associated with presence and composition of carotid atherosclerotic plaques, in particular with intraplaque hemorrhage. These findings provide further clues for understanding the development of vulnerable atherosclerotic plaque.

Aortic pulse wave velocity predicts focal white matter hyperintensities in a biracial cohort of older adults

Although the cross-sectional relationship of arterial stiffness with cerebral small vessel disease is consistently shown in middle-aged and young-old adults, it is less clear whether these associations remain significant over time in very old adults. We hypothesize that arterial stiffness is longitudinally associated with white matter characteristics, and associations are stronger within watershed areas. Neuroimaging was obtained in 2006-2008 from 303 elderly (mean age 82.9 years, 59% women, 41% black) with pulse wave velocity (PWV) measures in 1997-1998. Multivariable regression models estimated the coefficients for PWV (cm/sec) in relationship to presence, severity, and spatial distribution of white matter hyperintensities (WMH), gray matter volume, and fractional anisotropy from diffusion tensor, adjusting for demographic, cardiovascular risk factors, and diseases from 1997-1998 to 2006-2008. Higher PWV in 1997-1998 was associated with greater WMH volume in 2006-2008 within the left superior longitudinal fasciculus (age and total brain WMH adjusted, P=0.023), but not with WMH in other tracts or with fractional anisotropy or gray matter volume from total brain (P>0.2). Associations were stronger in blacks than in whites, remaining significant in fully adjusted models. Elderly with WMH in tracts related to processing speed and memory are more likely to have had higher PWV values 10 years prior, before neuroimaging data being available. Future studies should address whether arterial stiffness can serve as an early biomarker of covert brain structural abnormalities and whether early arterial stiffness control can promote successful brain aging, especially in black elderly.

Arterial Stiffness and Cerebral Small Vessel Disease

Background and Purpose—

Aging and vascular risk factors contribute to arterial stiffening. Increased arterial stiffness exposes the small vessels in the brain to abnormal flow pulsations and, as such, may contribute to the pathogenesis of cerebral small vessel disease. In a population-based study, we investigated the association between arterial stiffness, as measured by aortic pulse wave velocity (aPWV), and small vessel disease.

Methods—

Overall, 1460 participants (mean age, 58.2 years) underwent aPWV measurement and brain MRI scanning. We calculated aPWV by measuring time differences and distances between pulse waves in the carotid and femoral arteries. Using automated MRI analysis, we obtained white matter lesion volumes. Infarcts and microbleeds were rated visually. We used linear and logistic regression models to associate aPWV with small vessel disease, adjusting for age, sex, mean arterial pressure, and heart rate and additionally for cardiovascular risk factors. Subsequently, we explored associations in strata of hypertension.

Results—

In the study group, higher aPWV was associated with larger white matter lesion volume (difference in volume per SD increase in aPWV 0.07; 95% CI, 0.02–0.12) but not with lacunar infarcts or microbleeds. In persons with uncontrolled hypertension, higher aPWV was significantly associated with larger white matter lesion volume (difference in volume per SD increase in aPWV 0.09; 95% CI, 0.00–0.18), deep or infratentorial microbleeds (OR, 2.13; 95% CI, 1.16–3.91), and to a lesser extent also with lacunar infarcts (OR, 1.63; 95% CI, 0.98–2.70). No such associations were present in persons with controlled hypertension or without hypertension.

Conclusions—

In our study, increased arterial stiffness is associated with a larger volume of white matter lesions.

The Relation between Chronic Kidney Disease and Cerebral Microbleeds: Difference between Patients with and without Diabetes

Background

Cerebral microbleeds are an important radiologic marker of bleeding-prone brain and have been reported to be associated with the increased risk of intracerebral haemorrhage.

Aims

We sought to examine the association of chronic kidney disease with cerebral microbleeds, and determine whether the association differs between patients with and without diabetes.

Methods

A total of 909 patients with ischemic stroke who were consecutively admitted to our hospital were included in this study. We collected demographic, clinical, and laboratory data (including serum creatinine levels) and documented the presence and numbers of microbleeds. Kidney function was estimated by using the Modification of Diet in Renal Disease formula. We categorized estimated glomerular filtration rates into moderate to severe, mild, and normal (<60, 60–90, and >90 ml/min/1.73 m2, respectively).

Results

Cerebral microbleeds is most frequent in the moderate-to-severe chronic kidney disease group (45.6%). In patients without diabetes, mild and moderate-to-severe chronic kidney disease was found to be independently associated with the presence of cerebral microbleeds (adjusted odds ratio, 1.68; 95% confidence interval, 1.04–2.71 and adjusted odds ratio, 3.74; 95% confidence interval, 1.87–7.47) compared with normal kidney function. In patients with diabetes, however, this relationship was not found. Furthermore, ordinal logistic regression analysis revealed that an increased serum creatinine level and a reduced kidney function were associated with the number of cerebral microbleeds.

Conclusion

We found that chronic kidney disease is independently associated with cerebral microbleeds in patients without diabetes but not in patients with diabetes.

Blood fluidity enhancement by electrical acupuncture stimulation is related to an adrenergic mechanism

We have reported that electrical acupuncture stimulation (ACU) increases blood fluidity by decreasing platelet aggregation. In this study, we investigated the mechanism causing the increase of blood fluidity. The effects of ACU on blood fluidity and platelet adhesion were examined using a Micro Channel Array Flow Analyzer (MC-FAN) and a laser scattering platelet aggregometer (PA-20). Male Wistar rats (7-8 weeks old) were used in the study. ACU (1 or 100 Hz, 3-5 V), which causes slight muscle twitching, was applied to the ZuSanli (ST-36) acupoint for 15 or 60 minutes once/day. Blood samples were collected from the inferior vena cava. ACU applied to ST-36 revealed significant increases in blood fluidity, while platelet adhesion activity decreased, regardless of the difference of stimulus time. The acupuncture had an immediate effect. Even if naloxone was administered during acupuncture stimulus, the blood flow time shortened in a similar way, as in the only acupuncture stimulus group. In addition, the effect of acupuncture on blood fluidity was inhibited by a β-antagonist. The results indicate that ACU affects blood fluidity depending on the acupoints, and that the effect of ACU might involve an endogenous adrenergic mechanism.

Differences between hypertensive and atherosclerotic lesions in retinal arteries assessed by Scheie's classification in hypertensive patients following stroke

Scheie's classification regarding hypertensive and atherosclerotic lesions in retinal arteries is generally used to assess the severity of hypertensive retinopathy and the risks of cardiovascular events in hypertensive patients. However, the differences between these two types of retinal artery lesions have not been fully examined. Both arterial stiffness and aortic root diameter are increased in hypertensive patients. The aim of this study was to elucidate differences in the two types of lesions by comparing their relationships to arterial stiffness and aortic root diameter in hypertensive patients following stroke. Fifty-two hypertensive patients following stroke were divided into five stages according to Scheie's classification of hypertensive (H stage 0-4) and atherosclerotic (S stage 0-4) lesions by ophthalmologists. Arterial stiffness was measured as brachial-ankle pulse wave velocity (baPWV) using an automatic waveform analyzer. Aortic root diameter was measured using M-mode echocardiography. The H and S stages in retinal arteries correlated with each other (ρ = 0.443, p < 0.001). However, the S stage correlated with baPWV (ρ = 0.385, p = 0.005) and the aortic root diameter (ρ = 0.285, p = 0.043), while the H stage did not correlate with these parameters. Multiple stepwise regression analysis demonstrated that the aortic root diameter was independently associated with S stage (β = 0.373, p = 0.006), even though baPWV was independently associated with neither S stage nor H stage. In conclusion, hypertensive lesions (H stage) in retinal arteries are associated with atherosclerotic lesions (S stage) in retinal arteries. However, S stage may reflect arterial stiffening and aortic root dilatation better than H stage in hypertensive patients following stroke. This difference between H and S stages of Scheie's classification should be kept in mind when considering the association between retinal microcirculation and large vessel arteriosclerosis.

Differential effects of age and history of hypertension on regional brain volumes and iron

Aging affects various structural and metabolic properties of the brain. However, associations among various aspects of brain aging are unclear. Moreover, those properties and associations among them may be modified by age-associated increase in vascular risk. In this study, we measured volume of brain regions that vary in their vulnerability to aging and estimated local iron content via T2* relaxometry. In 113 healthy adults (19-83 years old), we examined prefrontal cortex (PFC), primary visual cortex (VC), hippocampus (HC), entorhinal cortex (EC), caudate nucleus (Cd), and putamen (Pt). In some regions (PFC, VC, Cd, and Pt) age-related differences in iron and volume followed similar patterns. However, in the medial-temporal structures, volume and iron content exhibited different age trajectories. Whereas age-related volume reduction was mild in HC and absent in EC, iron content evidenced significant age-related declines. In hypertensive participants significantly greater iron content was noted in all examined regions. Thus, iron content as measured by T2* may be a sensitive index of regional brain aging and may reveal declines that are more prominent than gross anatomical shrinkage.