Microalbuminuria is independently associated with deep or infratentorial brain microbleeds in hypertensive adults

A pictorial neuroradiological review of brain vascular abnormalities in patients with kidney disease

A well-known link exists between cerebrovascular disease and chronic kidney disease. Cerebrovascular pathology in patients with kidney disease may be asymptomatic and occasionally discovered through neuroradiological examinations or it may present with neurological symptoms. Covert cerebrovascular lesions represent the earliest injuries associated with chronic kidney disease and primarily result from small vessel damage. These conditions often manifest incidentally, appearing as structural changes (such as lacunes, white matter lesions, enlarged perivascular spaces, cerebral microbleeds, and atrophy) as well as microstructural and hemodynamic alterations, detectable through routine and advanced functional MRIs. These alterations may be associated with a higher risk of stroke, cognitive decline, and dementia. Patients with end-stage renal disease or chronic kidney disease undergoing dialysis may be at increased risk of large-artery atherosclerosis, cardio-embolism, or small-vessel occlusion, and they may experience symptomatic acute ischemic strokes as rare complications. Currently, there are no established guidelines or standardized diagnostic protocols for preventing cerebrovascular disease in patients with kidney disease. Clinical and radiological studies are warranted to evaluate the usefulness of incorporating neuroimaging into the diagnostic work-up of these patients in order to improve prognosis and reduce diagnostic delays.

Serum albumin and white matter hyperintensities

People living with HIV and those diagnosed with alcohol use disorders (AUD) relative to healthy individuals commonly have low levels of serum albumin, substantiated as an independent predictor of cardiovascular events. White matter hyperintensities (WMH)-a neuroimaging feature of cerebral small vessel disease-are also related to cardiovascular disease. Despite consensus regarding associations between high levels of urine albumin and WMH prevalence, and low serum albumin levels and impaired cognitive functioning, relations between serum albumin and WMH burdens have rarely been evaluated. Here, a sample including 160 individuals with AUD, 142 living with HIV, and 102 healthy controls was used to test the hypothesis that serum albumin would be inversely related to WMH volumes and directly related to cognitive performance in the two diagnostic groups. Although serum albumin and periventricular WMH volumes showed an inverse relationship in both AUD and HIV groups, this relationship persisted only in the HIV group after consideration of traditional cardiovascular (i.e., age, sex, body mass index (BMI), nicotine use, hypertension, diabetes), study-relevant (i.e., race, socioeconomic status, hepatitis C virus status), and disease-specific (i.e., CD4 nadir, HIV viral load, HIV duration) factors. Further, serum albumin contributed more significantly than periventricular WMH volume to variance in performance on a verbal learning and memory composite score in the HIV group only. Relations in both HIV and AUD groups between albumin and hematological red blood cell markers (e.g., hemoglobin, hematocrit) suggest that in this sample, serum albumin reflects hematological abnormalities. Albumin, a simple serum biomarker available in most clinical settings, may therefore help identify periventricular WMH burden and performance levels in specific cognitive domains in people living with HIV. Whether serum albumin contributes mechanistically to periventricular WMH in HIV will require additional investigation.

Serum albumin and white matter hyperintensities

Urine albumin, high in kidney disease, predicts cardiovascular incidents and CNS white matter hyperintensity (WMH) burdens. Serum albumin - a more general biomarker which can be low in several disorders - including kidney and liver disease, malnutrition, and inflammation - also predicts cardiovascular events and is associated with cognitive impairment in several clinical populations; relations between serum albumin and WMH prevalence, however, have rarely been evaluated. In a sample of 160 individuals with alcohol use disorder (AUD), 142 infected with HIV, and 102 healthy controls, the hypothesis was tested that lower serum albumin levels would predict larger WMH volumes and worse cognitive performance irrespective of diagnosis. After considering traditional cardiovascular risk factors (e.g., age, sex, body mass index (BMI), nicotine use, hypertension, diabetes) and study-relevant variables (i.e., primary diagnoses, race, socioeconomic status, hepatitis C virus status), serum albumin survived false discovery rate (FDR)-correction in contributing variance to larger periventricular but not deep WMH volumes. This relationship was salient in the AUD and HIV groups, but not the control group. In secondary analyses, serum albumin and periventricular WMH along with age, sex, diagnoses, BMI, and hypertension were considered for hierarchical contribution to variance in performance in 4 cognitive domains. Albumin survived FDR-correction for significantly contributing to visual and verbal learning and memory performance after accounting for diagnosis. Relations between albumin and markers of liver integrity [e.g., aspartate transaminase (AST)] and blood status (e.g., hemoglobin, red blood cell count, red cell distribution width) suggest that in this sample, albumin reflects both liver dysfunction and hematological abnormalities. The current results suggest that albumin, a simple serum biomarker available in most clinical settings, can predict variance in periventricular WMH volumes and performance in visual and verbal learning and memory cognitive domains. Whether serum albumin contributes mechanistically to periventricular WMH prevalence will require additional investigation.

Epidemiology and Risk Factors for Stroke in Chronic Kidney Disease: A Narrative Review

Patients with chronic kidney disease (CKD) have a higher risk ofboth ischemic and hemorrhagic stroke. This association appears to be partly independent from the higher prevalence of established risk factors for stroke in patients with CKD, including hypertension and atrial fibrillation. In the present review we aim to discuss the impact of CKD on the risk of stroke and stroke-related consequences, and explore the pathophysiology underpinning the increased risk of stroke in patients with CKD. We cover the clinical association between renal dysfunction and cerebrovascular disease including stroke, silent brain infarct, cerebral small vessel disease, microbleeds, and white matter hyperintensity, and discuss the underlying mechanisms.

Susceptibility artifact morphology is more conspicuous on susceptibility-weighted imaging compared to T2* gradient echo sequences in the brains of dogs and cats with suspected intracranial disease

Susceptibility-weighted imaging (SWI) has been found to be more reliable in the detection of vessels and blood products than T2*-weighted gradient echo (GE) in several human brain diseases. In veterinary medicine, published information on the diagnostic usefulness of SWI is lacking. The aim of this retrospective observational study was to investigate the value of SWI compared to T2*-weighted GE images in a population of dogs and cats with presumed, MRI-based diagnoses grouped as neoplastic (27), cerebrovascular (14), inflammatory (14), head trauma (5), other pathologies (4), or that were normal (36). Areas of signal void (ASV) were assessed based on shape, distribution, number, and conspicuity. Presence of ASV was found in 31 T2*-weighted GE and 40 SWI sequences; the conspicuity of lesions increased in 92.5% of cases with SWI. A 44.7% increase in the number of cerebral microbleeds (CMBs) was identified within the population using SWI (110) compared to T2*-weighted GE (76). Linear ASV presumed to be abnormal vascular structures, as are reported in humans, were identified in 12 T2*-weighted GE and 19 SWI sequences. In presumed brain tumors, abnormal vascular structures were detected in 11 of 27 (40.7%) cases on T2*-weighted GE and in 16 of 27 (59.3%) cases on SWI, likely representing tumor neovascularization; amorphous ASV interpreted as presumed hemorrhages on T2*-weighted GE were diagnosed as vessels on SWI in five of 27 (18.5%) cases. Since SWI shows ASV more conspicuously than T2*-weighted GE, the authors advocate the use of SWI in veterinary patients.

Development of a stroke risk score with MRI asymptomatic brain lesions attributes to evaluate prognostic vascular events

BACKGROUND

The use of a combination of stroke predictors, such as clinical factors and asymptomatic lesions on brain magnetic resonance imaging (MRI), may improve the accuracy of stroke risk prediction. Therefore, we attempted to develop a stroke risk score for healthy individuals.

METHODS

We investigated the presence of cerebral stroke in 2365 healthy individuals who underwent brain dock screening at the Health Science Center in Shimane. We examined the factors that contributed to stroke and attempted to determine the risk of stroke by comparing background factors and MRI findings.

RESULTS

The following items were found to be significant risk factors for stroke: age (≥60 years), hypertension, subclinical cerebral infarction, deep white matter lesion, and microbleeds. Each item was scored with 1 point, and the hazard ratios for the risk of developing stroke based on the group with 0 points were 17.2 (95% confidence interval [CI] 2.31-128) for 3 points, 18.1 (95% CI 2.03-162) for 4 points, and 102 (95% CI 12.6-836) for 5 points.

CONCLUSIONS

A precise stroke prediction score biomarker can be obtained by combining MRI findings and clinical factors.

Urinary Immunoglobulin G Is Associated with Deep and Infratentorial Cerebral Microbleeds in Stroke Patients

BACKGROUND

Cerebral microbleeds (CMBs) detected on susceptibility-weighted imaging (SWI) are associated with cerebral small vessel disease. Chronic kidney disease and microalbuminuria have been associated with the presence of CMBs in stroke patients. Urinary immunoglobulin G (IgG) is measured to document glomerular injury; however, the relationship between urinary IgG and CMBs is unknown.

METHODS

We retrospectively enrolled consecutive patients who had been admitted with transient ischemic attack (TIA) or ischemic stroke and identified those who had undergone SWI and a spot urine test. The location of CMBs was classified on magnetic resonance imaging as strictly lobar, deep/infratentorial (D/I), or mixed areas. We analyzed the association between urinary IgG and the presence and location of CMBs.

RESULTS

We included 298 patients (86 female, median age 70 years, median eGFR 65.8 mL/min/1.73 m2). Positive urinary IgG and CMB results were found in 58 (19%) and 160 patients (54%), respectively. Urinary IgG positivity was significantly associated with CMBs compared with non-CMBs (28% vs. 9%, p < 0.001), and with D/I or mixed CMBs compared with non-D/I or mixed CMBs (34% vs. 10%, p < 0.001). Multivariate analysis revealed that urinary IgG and hypertension positivity were strongly associated with D/I or mixed CMBs (OR 3.479, 95% CI: 1.776-6.818, p < 0.001; OR 3.415, 95% CI: 1.863-6.258, p < 0.001).

CONCLUSIONS

Urinary IgG was associated with the prevalence of D/I or mixed location CMBs in TIA or ischemic stroke patients. Our findings provide new insights into the association between urinary IgG and the distribution of CMBs.

Increased Cerebral Small Vessel Disease Burden With Renal Dysfunction and Albuminuria in Patients Taking Antithrombotic Agents: The Bleeding With Antithrombotic Therapy 2

Background The aim of this study was to determine the associations of cerebral small vessel disease (SVD) burden with renal dysfunction and albuminuria in patients taking oral antithrombotic agents. Methods and Results Patients who newly started or continued taking oral antiplatelets or anticoagulants were enrolled in a prospective, multicenter, observational study. Obligatorily acquired multimodal magnetic resonance imaging at registration with prespecified imaging conditions was assessed for cerebral microbleeds, white matter hyperintensities, enlarged basal ganglia perivascular spaces, or lacunes, and an ordinal SVD score was calculated (range, 0-4). Multivariable adjusting covariates were age, sex, hypertension, diabetes, dyslipidemia, current smoking, drinking, and estimated glomerular filtration rate (eGFR). Of 5324 patients (1762 women; median age, 73 years), 4797 (90.1%) patients were taking oral antithrombotic agents for secondary stroke prevention. Cerebral microbleeds were present in 32.7%, confluent white matter hyperintensities in 51.8%, extensive basal ganglia perivascular spaces in 38.9%, and lacunes in 59.4%. Median SVD score was 2. Compared with eGFR category G1 (eGFR ≥90 mL/min per 1.73 m2), adjusted odds ratios for SVD score increment were 1.63 (95% CI, 1.11-2.39) at category G4 (eGFR 15-<30 mL/min per 1.73 m2) and 2.05 (95% CI, 1.33-3.16) at G5 (eGFR <15 mL/min per 1.73 m2). Corresponding odds ratios relative to urinary albumin-to-creatinine ratio (ACR) category A1 (ACR <30 mg/g) were 1.29 (95% CI, 1.12-1.49) for category A2 (ACR 30-<300 mg/g) and 1.37 (95% CI, 1.05-1.77) for A3 (ACR ≥300 mg/g). When combined eGFR and ACR categories were assessed, risks for SVD score increment generally increased as eGFR decreased and ACR increased. Conclusions Both reduced eGFR and albuminuria were independently associated with increased cerebral SVD burden in patients requiring oral antithrombotic medication mainly for secondary stroke prevention. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01581502; URL: https://www.umin.ac.jp/ctr; Unique identifier: UMIN000023669.

The Multiscale Dynamics of Beat-to-Beat Blood Pressure Fluctuation Links to Functions in Older Adults

Background

The blood pressure (BP) is regulated by multiple neurophysiologic elements over multiple temporal scales. The multiscale dynamics of continuous beat-to-beat BP series, which can be characterized by “BP complexity”, may, thus, capture the subtle changes of those elements, and be associated with the level of functional status in older adults. We aimed to characterize the relationships between BP complexity and several important functions in older adults and to understand the underlying factors contributing to BP complexity.

Method

A total of 400 older adults completed a series of clinical and functional assessments, a finger BP assessment of at least 10 min, and blood sample and vessel function tests. Their hypertensive characteristics, cognitive function, mobility, functional independence, blood composition, arterial stiffness, and endothelial function were assessed. The complexity of systolic (SBP) and diastolic (DBP) BP series was measured using multiscale entropy.

Results

We observed that lower SBP and DBP complexity was significantly associated with poorer functional independence (β > 0.17, p < 0.005), cognitive function (β > 0.45, p = 0.01), and diminished mobility (β < −0.57, p < 0.003). Greater arterial stiffness (β < −0.48, p = 0.02), decreased endothelial function (β > 0.42, p < 0.03), and excessed level of blood lipids (p < 0.03) were the main contributors to BP complexity.

Conclusion

Blood pressure complexity is closely associated with the level of multiple functional statuses and cardiovascular health in older adults with and without hypertension, providing novel insights into the physiology underlying BP regulation. The findings suggest that this BP complexity metric would serve as a novel marker to help characterize and manage the functionalities in older adults.

The role of urinary albumin-to-creatinine ratio as a biomarker to predict stroke: A meta-analysis and systemic review

Albuminuria excretion rate, calculated as urinary albumin-to-creatinine ratio (UACR), is used clinically to evaluate albuminuria. There are different attitudes to whether high UACR predicts higher risk of stroke. The aim of this study was to evaluate the relationship between UACR and stroke. Two investigators independently searched MEDLINE, EMBASE, Cochrane Controlled Trials Register Database, Scopus and Google Scholar from January 1966 through June 2021 were screened. In addition, a manual search was conducted using the bibliographies of original papers and review articles on this topic. Two blinded reviewers abstracted the data independently to a predefined form. Among the 10,939 initially identified studies, 7 studies with 159,302 subjects were finally included. It is demonstrated that UACR predicted an increased risk of stroke using cutoff value of either 0.43 (HR, 2.39; 95% CI: 1.24 - 4.61; P <0.01), 10 mg/g (HR, 1.60; 95% CI: 1.30 - 1.97; P < 0.01) or 30 mg/g (HR, 1.84; 95% CI: 1.49 - 2.28; P < 0.01). The overall analysis confirmed that high UACR was associated with an increased rate of stroke (HR, 1.81; 95% CI: 1.52 - 2.17; P < 0.01). Furthermore, High UACR predicted higher risk of stroke in local inhabitants (HR, 1.67; 95% CI: 1.17 – 2.37; P = 0.04), adults (HR, 2.21; 95% CI: 2.07 – 2.36; P < 0.01) or elderly adults (HR, 1.96; 95% CI: 1.56 – 2.46; P < 0.01). Whereas, high UACR was unable to predict stroke in patients with either T2DM (HR, 2.25; 95% CI: 0.55 – 9.17; P = 0.26) or hypertension (HR, 0.95; 95% CI: 0.28 – 3.22; P = 0.93). Another subgroup analysis revealed that high UACR was associated with increased risk of ischemic stroke (HR, 1.60; 95% CI: 1.43 - 1.80; P < 0.01), as well as hemorrhagic stroke (HR, 1.76; 95% CI: 1.22 - 1.45; P < 0.01). In conclusion, UACR is associated with an increased risk of hemorrhagic and ischemic stroke. UACR may be used as an indicator to predict stroke in non-diabetic and non-hypertensive subjects.

Impact of stroke history on the presence of cerebral microbleeds in hemodialysis patients

Introduction

Cerebral microbleeds (CMBs) are detected on gradient-echo T2*-weighted magnetic resonance imaging (MRI). Clinically, CMBs are often detected after stroke, including in cases of intracerebral hemorrhage and ischemic cerebrovascular disease. Hemodialysis (HD) patients are widely known to have a high incidence of stroke, and HD patients without stroke history have been reported to have a high prevalence of CMBs. In this study, we investigated whether history of stroke affects the prevalence of CMBs in HD patients.

Methods

A cross-sectional study was performed in 241 HD patients who underwent brain T2*-weighted MRI. We compared the prevalence of CMBs between the patients with and without a history of stroke. Moreover, the relationship between history of stroke and presence of CMBs was examined by multivariate logistic regression analysis.

Results

Among these patients, 22 (9.1%) had a history of stroke. CMBs were detected in 70 patients (29.0%). The prevalence of CMBs was significantly higher in patients with a history of stroke compared to those without this history (54.5 vs. 26.5%, p = 0.012). In the multivariable analysis adjusted for background characteristics, history of stroke was a significant and independent factor related to CMBs (OR: 3.24, 95%CI: 1.18–8.89, p = 0.02).

Discussion/conclusions

As has been reported for non-dialysis patients, our results showed a high prevalence of CMBs in HD patients with a history of stroke, and indicated that a history of stroke is significantly and independently associated with CMBs in HD patients.

Antiplatelet therapy and future intracerebral hemorrhage in hemodialysis patients with cerebral microbleeds

The use of antiplatelet drugs is thought to increase the risk for intracerebral hemorrhage (ICH) in patients with cerebral microbleeds (CMBs). However, hemodialysis (HD) patients have a high prevalence of CMBs and diverse pathologies that require antiplatelet therapy. In this study, we investigated whether the use of antiplatelet drugs increases the risk for ICH in HD patients with CMBs. Brain magnetic resonance imaging (MRI), including T2*-weighted MRI, was performed in 179 HD patients with no history of cerebrovascular events. CMBs were detected and patients were followed prospectively with a median follow-up period of 5.2 [1.4-6.2] years. To investigate whether the influence of antiplatelet therapy on the development of ICH differs in cases with and without CMBs, the inverse probability of treatment weighting method was used, including an interaction term between the presence or absence of CMBs and use of antiplatelet drugs. As a result, CMBs were detected in 45 patients (25.1%), and antiplatelet drugs were used in 66 patients (36.9%). When the effect of antiplatelet therapy on the incidence of ICH was modified by the presence of CMBs at baseline (P for interaction <0.001), the use of antiplatelet drugs was a significant risk factor for ICH in HD patients without CMBs, but not in HD patients with CMBs. Furthermore, the burden of CMBs significantly increased the risk for ICH, but the increase in this risk was slower in antiplatelet drug users as compared to non-antiplatelet drug users (P for interaction = 0.02). The influence of antiplatelet drugs on the development of ICH differed depending on the presence or absence of CMBs. In fact, the use of antiplatelet drugs did not increase the risk for ICH in HD patients with CMBs.

Multiscale Dynamics of Blood Pressure Fluctuation Is Associated With White Matter Lesion Burden in Older Adults With and Without Hypertension: Observations From a Pilot Study

Background: White matter lesions (WMLs) are highly prevalent in older adults, and hypertension is one of the main contributors to WMLs. The blood pressure (BP) is regulated by complex underlying mechanisms over multiple time scales, thus the continuous beat-to-beat BP fluctuation is complex. The association between WMLs and hypertension may be manifested as diminished complexity of BP fluctuations. The aim of this pilot study is to explore the relationships between hypertension, BP complexity, and WMLs in older adults. Method: Fifty-three older adults with clinically diagnosed hypertension and 47 age-matched older adults without hypertension completed one MRI scan and one BP recording of 10-15 min when sitting quietly. Their cerebral WMLs were assessed by two neurologists using the Fazekas scale based on brain structural MRI of each of their own. Greater score reflected higher WML grade. The complexity of continuous systolic (SBP) and diastolic (DBP) BP series was quantified using multiscale entropy (MSE). Lower MSE reflected lower complexity. Results: Compared to the non-hypertensive group, hypertensives had significantly greater Fazekas scores (F > 5.3, p < 0.02) and lower SBP and DBP complexity (F > 8.6, p < 0.004). Both within each group (β < -0.42, p < 0.01) and across groups (β < -0.47, p < 0.003), those with lower BP complexity had higher Fazekas score. Moreover, complexity of both SBP and DBP mediated the influence of hypertension on WMLs (indirect effects > 0.25, 95% confidence intervals = 0.06 - 0.50). Conclusion: These results suggest that diminished BP complexity is associated with WMLs and may mediate the influence of hypertension on WMLs. Future longitudinal studies are needed to examine the causal relationship between BP complexity and WMLs.

Cerebro-renal interaction and stroke

Stroke is an event causing a disturbance in cerebral function leading to death and disability worldwide. Both acute kidney injury and chronic kidney disease (CKD) are associated with an increased risk of stroke and cerebrovascular events. The underlying mechanistic approach between impaired renal function and stroke is limitedly explored and has attracted researchers to learn more for developing therapeutic intervention. Common risk factors such as hypertension, hyperphosphatemia, atrial fibrillation, arteriosclerosis, hyperhomocysteinemia, blood-brain barrier disruption, inflammation, etc. are observed in the general population, but are high in renal failure patients. Also, risk factors like bone mineral metabolism, uremic toxins, and anemia, along with the process of dialysis in CKD patients, eventually increases the risk of stroke. Therefore, early detection of risks associated with stroke in CKD is imperative, which may decrease the mortality associated with it. This review highlights mechanisms by which kidney dysfunction can lead to cerebrovascular events and increase the risk of stroke in renal impairment.

Oral anticoagulant use and the development of new cerebral microbleeds in cardioembolic stroke patients with atrial fibrillation

OBJECTIVE

Cerebral microbleeds (CMBs) are a magnetic resonance imaging (MRI) marker for cerebral small vessel disease. Existing CMBs and those that newly develop are associated with the risks of stroke incidence and recurrence. The purpose of the present study was to investigate the association of oral anticoagulant (OAC) use and the development of new CMBs in cardioembolic stroke patients with atrial fibrillation.

SUBJECTS AND METHODS

We prospectively followed cardioembolic stroke patients with atrial fibrillation who had been hospitalized in the stroke center of our hospital, had been prescribed anticoagulants at discharge, and underwent repeated brain MRI with an interval of at least one year from the baseline MRI. Assessing the presence, number and location of CMBs using T2*-weighted gradient-recalled echo MRI, we used logistic regression models to investigate the associations between OAC use and the incidence of new CMBs. We also examined associations of subsequent stroke with OACs and CMBs during the follow-up.

RESULTS

A total of 81 patients, consisting of 45 patients receiving direct oral anticoagulants (DOACs) and 36 patients receiving warfarin (WF), were analyzed in the present study. Baseline CMBs were observed in 19/81 patients (23.5%) and new CMBs in 18/81 patients (22.2%) on follow-up MRI (median interval, 34 months). Of the 31 new CMBs, 25 (80.6%) developed in the lobar location and 6 (19.4%) in the deep or infratentorial location. New CMBs occurred in 4 patients (10.0%) taking DOACs　alone, in 10 patients (35.7%) taking WF alone, in 3 patients (37.5%) taking WF plus antiplatelet agents and in 1 patient (20.0%) taking DOAC plus antiplatelet agent. Regarding location, the new CMBs were the lobar type in 7 of the 10 patients taking WF alone, as well as in 3 of the 4 patients taking DOACs alone. In multivariate analysis, the presence of CMBs at baseline and WF use (vs. DOAC use) were associated with new CMBs (CMB presence at baseline: OR 4.16, 95% CI 1.19-14.44; WF use: OR 3.38, 95% CI 1.02-11.42). The presence of ≥ 2 CMBs at baseline was related to a higher risk of subsequent stroke (OR 7.25, 95% CI 1.01-52.35, P = 0.048).

CONCLUSION

Our findings suggest that DOAC compared with WF use at discharge is associated with a lower incidence of new CMBs in cardioembolic stroke patients with atrial fibrillation. Further prospective studies in the clinical setting are needed to confirm our exploratory data.

Cystatin C, cognition, and brain MRI findings in 90+-year-olds

Chronic kidney disease is emerging as a novel risk factor for cerebrovascular disease, but this association remains largely unexplored in older adults. Cystatin C is a more accurate measure than creatinine of kidney function in the elderly. We evaluated cystatin C, cognitive function, and brain imaging in 193 participants from The 90+ Study neuroimaging component. The mean age was 93.9 years; 61% were women. Mean cystatin C was 1.62 mg/L with estimated glomerular filtration rate 39.2 mL/min/1.73 m². Performance on measures of global cognition, executive function, and visual-spatial ability declined at higher tertiles of cystatin C (lower kidney function). Higher cystatin C was significantly associated with infratentorial microbleeds and lower gray matter volume. Adjusted risk of incident dementia was increased in the middle and high cystatin C tertile groups compared with the low group (hazard ratio in highest tertile 3.81 [95% confidence interval 1.14-12.7]), which appeared to be explained in part by the presence of cerebral microbleeds. Overall, cystatin C was associated with cognitive performance, brain imaging pathology, and decline to dementia in this oldest-old cohort.

Underlying embolic and pathologic differentiation by cerebral microbleeds in cryptogenic stroke

BACKGROUND

Cryptogenic stroke encompasses diverse emboligenic mechanisms and pathogeneses. Cerebral microbleeds (CMBs) occur differently among stroke subtypes. The association of CMBs with cryptogenic stroke is essentially unknown.

METHODS

CHALLENGE ESUS/CS (Mechanisms of Embolic Stroke Clarified by Transesophageal Echocardiography for ESUS/CS) is a multicenter registry with comprehensive data including gradient-echo T2*-weighted magnetic resonance imaging of cryptogenic stroke patients who underwent transesophageal echocardiography. Patients' clinical characteristics were compared according to the presence and location of CMBs.

RESULTS

A total of 661 patients (68.7 ± 12.7 years; 445 males) were enrolled, and 209 (32%) had CMBs. Age (odds ratio [OR] 1.02, 95% confidence interval [CI] 1.00-1.04, p = 0.020), male sex (OR 1.85, 95% CI 1.18-2.91, p = 0.007), hypertension (OR 1.71, 95% CI 1.03-2.86, p = 0.039), chronic kidney disease (OR 1.64, 95% CI 1.11-2.43, p = 0.013), deep and subcortical white matter hyperintensity (OR 1.82, 95% CI 1.16-2.85, p = 0.009), and periventricular hyperintensity (OR 2.18, 95% CI 1.37-3.46, p = 0.001) were independently associated with the presence of CMBs. Aortic complicated lesions (OR 1.78, 95% CI 1.12-2.84, p = 0.015) were associated with deep and diffuse CMBs, whereas prior anticoagulant therapy (OR 7.88, 95% CI, 1.83-33.9, p = 0.006) was related to lobar CMBs.

CONCLUSIONS

CMBs were common, and age, male sex, hypertension, chronic kidney disease, and cerebral white matter diseases were related to CMBs in cryptogenic stroke. Aortic complicated lesions were associated with deep and diffuse CMBs, while prior anticoagulant therapy was related to lobar CMBs.

Cerebral microbleeds: hearing through the silence-a narrative review

OBJECTIVE

The term cerebral microbleed (CMB) refers to lesions documented as unexpected findings during computed tomography or magnetic resonance imaging examination of the brain. Initially, a CMB was thought to represent hemosiderin-laden macrophages marking an area of a tiny hemorrhage. Recently, histopathologic studies have shown that the structure of a CMB can be variable. To aid in dealing with this finding and judging its clinical significance, this review addresses important aspects of a CMB, including the definition, prevalence, and incidence in various populations, end-organ damage, associated conditions, and whether any action or treatment by the clinician might be indicated.

METHODS

PubMed Medline, EMBASE, BIOSIS, Current Contents, and Derwent Drug Files databases were searched for the keywords "microbleeds-detection-damage", "silent bleeds", "microbleeds", or "silent bleeds AND hemophilia" from 2011-2016. References of retrieved articles were also reviewed and included if applicable.

RESULTS

The published data are found primarily in the imaging literature and focus on diagnostic techniques. Some publications address relationships with diverse, co-existing clinical conditions and implications for treatment, especially in stroke, intracranial hemorrhage, and antithrombotic therapy.

CONCLUSIONS

It is critical for non-radiologist clinicians (primary care, internists, neurologists, hematologists) to be aware of the potential importance of the finding of a CMB, and the fact that these lesions are not always truly silent or without important clinical consequences. As additional studies appear, clinicians may be able to "hear" more clearly through the silence of the CMB and understand potential clinical implications in patients.

The AGES-Reykjavik Study suggests that change in kidney measures is associated with subclinical brain pathology in older community-dwelling persons

Decreased glomerular filtration rate (GFR) and albuminuria may be accompanied by brain pathology. Here we investigated whether changes in these kidney measures are linked to development of new MRI-detected infarcts and microbleeds, and progression of white matter hyperintensity volume. The study included 2671 participants from the population-based AGES-Reykjavik Study (mean age 75, 58.7% women). GFR was estimated from serum creatinine, and albuminuria was assessed by urinary albumin-to-creatinine ratio. Brain MRI was acquired at baseline (2002-2006) and 5 years later (2007-2011). New MRI-detected infarcts and microbleeds were counted on the follow-up scans. White matter hyperintensity progression was estimated as percent change in white matter hyperintensity volumes between the two exams. Participants with a large eGFR decline (over 3 ml/min/1.73m2 per year) had more incident subcortical infarcts (odds ratio 1.53; 95% confidence interval 1.05, 2.22), and more marked progression of white matter hyperintensity volume (difference: 8%; 95% confidence interval: 4%, 12%), compared to participants without a large decline. Participants with incident albuminuria (over 30 mg/g) had 21% more white matter hyperintensity volume progression (95% confidence interval: 14%, 29%) and 1.86 higher odds of developing new deep microbleeds (95% confidence interval 1.16, 2.98), compared to participants without incident albuminuria. The findings were independent of cardiovascular risk factors. Changes in kidney measures were not associated with occurrence of cortical infarcts. Thus, larger changes in eGFR and albuminuria are associated with increased risk for developing manifestations of cerebral small vessel disease. Individuals with larger changes in these kidney measures should be considered as a high risk population for accelerated brain pathology.

Association of Chronic Kidney Disease With Small Vessel Disease in Patients With Hypertensive Intracerebral Hemorrhage

Background

Chronic kidney disease (CKD) has been closely associated with hypertension and stroke. Although studies have reported the relationship between CKD and cerebral small vessel disease (SVD), the link between CKD, hypertension, and SVD is uncertain. The aim of this study was to investigate the association between CKD and SVD in patients with strictly hypertensive intracerebral hemorrhage (ICH).

Methods

142 patients with acute hypertensive ICH were enrolled in this study. Magnetic resonance imaging was performed to assess imaging markers for SVD. Patients were categorized into three CKD groups based on the degree of kidney dysfunction [glomerular filtration rate (GFR) in milliliters per minute per 1.73 m²]: normal kidney function (GFR ≥ 90), mild kidney disease (60 ≤ GFR < 90), and moderate to severe kidney disease (GFR < 60).

Results

The prevalence rate of mild and moderate to severe CKD was 50 and 14.8%, respectively. The stage of CKD was associated with history of chronic hypertension (p = 0.046) as well as the prevalence rate of overall and deep cerebral microbleed (CMB) (p = 0.001 and p = 0.002, respectively). The stage of CKD was a significant risk factor for deep white matter hyperintensity (WMH) (OR 1.848; 95% CI 1.022–3.343, p = 0.042), overall CMB (OR 2.628; 95% CI 1.462–4.724, p = 0.001), lobar CMB (OR 2.106; 95% CI 1.119–3.963, p = 0.021), and deep CMB (OR 2.237; 95% CI 1.263–3.960, p = 0.006), even after adjustment for confounders.

Conclusion

In patients with hypertensive ICH, the prevalence of CKD is high even at the early stage of renal function impairment and is associated with the prevalence of CMB and deep WMH. These results reinforce the notion of a link between hypertensive vasculopathy, renal function impairment, and cerebral SVD.

Age-Specific Associations of Renal Impairment With Magnetic Resonance Imaging Markers of Cerebral Small Vessel Disease in Transient Ischemic Attack and Stroke

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Background and Purpose—

It has been hypothesized that cerebral small vessel disease (SVD) and chronic renal impairment may be part of a multisystem small-vessel disorder, but their association may simply be as a result of shared risk factors (eg, hypertension) rather than to a systemic susceptibility to premature SVD. However, most previous studies were hospital based, most had inadequate adjustment for hypertension, many were confined to patients with lacunar stroke, and none stratified by age.

Methods—

In a population-based study of transient ischemic attack and ischemic stroke (OXVASC [Oxford Vascular Study]), we evaluated the magnetic resonance imaging markers of cerebral SVD, including lacunes, white matter hyperintensities, cerebral microbleeds, and enlarged perivascular space. We studied the age-specific associations of renal impairment (estimated glomerular filtration rate <60 mL/min per 1.73 m²) and total SVD burden (total SVD score) adjusting for age, sex, vascular risk factors, and premorbid blood pressure (mean blood pressure during 15 years preevent).

Results—

Of 1080 consecutive patients, 1028 (95.2%) had complete magnetic resonance imaging protocol and creatinine measured at baseline. Renal impairment was associated with total SVD score (odds ratio [OR], 2.16; 95% confidence interval [CI], 1.69–2.75; P<0.001), but only at age <60 years (<60 years: OR, 3.97; 95% CI, 1.69–9.32; P=0.002; 60–79 years: OR, 1.01; 95% CI, 0.72–1.41; P=0.963; ≥80 years: OR, 0.95; 95% CI, 0.59–1.54; P=0.832). The overall association of renal impairment and total SVD score was also attenuated after adjustment for age, sex, history of hypertension, diabetes mellitus, and premorbid average systolic blood pressure (adjusted OR, 0.76; 95% CI, 0.56–1.02; P=0.067), but the independent association of renal impairment and total SVD score at age <60 years was maintained (adjusted OR, 3.11; 95% CI, 1.21–7.98; P=0.018). Associations of renal impairment and SVD were consistent for each SVD marker at age <60 years but were strongest for cerebral microbleeds (OR, 5.84; 95% CI, 1.45–23.53; P=0.013) and moderate–severe periventricular white matter hyperintensities (OR, 6.28; 95% CI, 1.54–25.63; P=0.010).

Conclusions—

The association of renal impairment and cerebral SVD was attenuated with adjustment for shared risk factors at older ages, but remained at younger ages, consistent with a shared susceptibility to premature disease.

Putative Cerebral Microbleeds in Dogs Undergoing Magnetic Resonance Imaging of the Head: A Retrospective Study of Demographics, Clinical Associations, and Relationship to Case Outcome

BACKGROUND

Cerebral microbleeds (CMBs) are focal intraparenchymal signal voids on gradient-echo magnetic resonance imaging (MRI), corresponding to regions of chronic hemorrhage. In humans, they are associated with systemic disease and shorter survival times. Although similar findings have been identified in dogs, their epidemiology and clinical correlations have not been investigated.

OBJECTIVE

To determine epidemiological features, clinical associations, and associations with outcome for putative CMB-like foci (putative microbleeds [pMBs]) identified by T2*-weighted MRI in dogs.

ANIMALS

Five hundred and eighty-two dogs undergoing 3T brain MRI between 2011 and 2016.

METHODS

Retrospective case-control study. Demographic, diagnostic, and clinicopathological data were obtained from medical records and phone follow-up. Demographic variables were compared between dogs with and without evidence of pMBs. For dogs with such evidence, and a subset of matched controls, associations with clinical presentation, concurrent disease, and survival times were evaluated.

RESULTS

Dogs with pMBs were older (P < .001) and smaller (P = .004) than unaffected dogs. Compared to matched controls, they presented more frequently for vestibular signs (P = .030). Cortical atrophy occurred concurrently with pMBs in 26% (14/54) of dogs. Diagnosed renal disease was not significantly associated with pMBs, but proteinuria was more common in dogs with pMBs than in matched controls (odds ratio = 3.01, P = .005). Dogs with pMBs had a shorter median survival time than did matched controls (P = .011).

CONCLUSIONS AND CLINICAL IMPORTANCE

Putative microbleeds occurred in 54 of 582 (9.3%) of dogs undergoing brain MRI, but may not be a normal consequence of aging. They were associated with shorter survival time and proteinuria in the study population.

Serum cystatin C is associated with large cerebral artery stenosis in acute ischemic stroke

Large cerebral artery stenosis is a major cause of acute ischemic stroke (AIS); however, the correlation between serum cystatin C (CysC) and the stenosis of large cerebral arteries in patients with AIS has not been established. We performed a retrospective review of acute ischemic stroke patients, who were examined by cerebral digital subtraction angiography(DSA). Participants (252 cases) included 131 patients without stenosis and 121 patients with large cerebral artery stenosis. Serum CysC levels in patients with large cerebral artery stenosis were much higher than that of control subjects (p<0.001). However, serum CysC levels were not related to the location of stenosis. Further, logistic regression analyses showed that increased serum CysC was an independent risk factor of large cerebral artery stenosis in patients with acute ischemic stroke. Total participants were subdivided into quintiles based on serum CysC levels. Compared with the first quintile, the odds ratios of risk for large cerebral artery stenosis in the fourth and the fifth quintile were 1.26 (p<0.05) and 4.71(p<0.05) respectively, after the adjustment for age, sex, and smoking, hypertension, type 2 diabetes mellitus(DM), dyslipidemia, creatinine(Cr), urea, uric acid, and C reactive protein(CRP). Therefore, a significant positive correlation was observed between elevated serum CysC levels and large cerebral artery stenosis in patients with acute ischemic stroke. In summary, our findings provide new insights into the correlation between increased serum CysC and large cerebral artery stenosis in patients with acute ischemic stroke.

Brain-kidney cross-talk: Definition and emerging evidence

Cross-talk is broadly defined as endogenous homeostatic signaling between vital organs such as the heart, kidneys and brain. Kidney-brain cross-talk remains an area with excitingly few publications despite its purported clinical relevance in the management of currently undertreated conditions such as resistant hypertension. Therefore, this review aims to establish an organ-specific definition for kidney-brain cross-talk and review the available and forthcoming literature on this topic.

Influence of cerebral white matter hyperintensities on cognitive impairment in elderly medical patients

AIM

We investigated the characteristics of elderly medical patients with white matter hyperintensities on magnetic resonance imaging.

METHODS

A total of 213 patients (123 men and 90 women; mean age 74.8 years) reported their history of hypertension, diabetes, dyslipidemia, previous stroke, coronary heart disease and chronic kidney disease (CKD). All patients completed the Mini-Mental State Examination and Geriatric Depression Scale. White matter hyperintensities were evaluated for the periventricular region, basal ganglia (BGH), deep white matter and infratentorial region, and brain atrophy was calculated as bicaudate ratios.

RESULTS

Patients with cognitive impairment (Mini-Mental State Examination score < 24) were significantly older (P = 0.001), had periventricular region hyperintensities (P = 0.029) and BGH (P = 0.0015), and showed atrophy (P < 0.0001). Logistic regression showed that cognitive impairment was predicted by stroke (OR 2.5, 95% CI 0.033-0.894, P = 0.036) and atrophy (OR 8.43, 95% CI 5.71-37.0, P = 0.0109). Multiple regressions showed that BGH was associated with CKD (β = 0.213; P = 0.003), and infratentorial region was associated with stroke (β = 0.157; P =0.035) and CKD (β = 0.172; P = 0.016). Periventricular region was associated with age (β = 0.2; P = 0.011) and Geriatric Depression Scale (β = 0.151; P = 0.037), and deep white matter hyperintensities with age (β = 0.189; P = 0.016).

CONCLUSIONS

Although cognitive impairment in elderly medical patients is associated with stroke and brain atrophy, white matter hyperintensities, especially BGH and infratentorial region, are associated with cognitive decline in relation to CKD. Geriatr Gerontol Int 2017; 17: 1488-1493.

Higher Levels of Cystatin C Are Associated with Extracranial Carotid Artery Steno-Occlusive Disease in Patients with Noncardioembolic Ischemic Stroke

Background

Large artery atherosclerosis is a major cause of ischemic stroke worldwide. Differential biomarker profiles associated with extra- and intracranial atherosclerosis are a topic of considerable interest. Cystatin C (CysC), a marker of renal function, is a risk factor for cardiovascular disease.

Aim

We sought to determine whether CysC levels were associated with extra- and intracranial large artery stenosis (LAS) in patients with acute ischemic stroke.

Methods

We retrospectively analyzed data of acute noncardioembolic ischemic stroke patients who were admitted to our stroke center within 5 days from symptom onset. Serum CysC levels were measured using latex agglutination turbidimetric immunoassay. Extra- and intracranial LAS were defined as ≥50% diameter stenosis or occlusion of the relevant internal carotid artery (ICA) and/or middle cerebral artery (MCA) using carotid echography and volume rendering on magnetic resonance angiography. Multivariate logistic analyses were used to assess the association between CysC levels and LAS after adjustment for potential confounders.

Results

Of 205 patients (mean age 70.2 years), 76 (37.1%) had LAS. The distribution of LAS was 29 extracranial ICA, 34 intracranial ICA/MCA (8 ICA only, 25 MCA only, 1 ICA+MCA) and 13 tandem stenosis (both extracranial ICA and intracranial ICA/MCA). Levels of CysC were higher in patients with extracranial ICA stenosis than in those with intracranial ICA/MCA stenosis (1.23 ± 0.33 vs. 0.97 ± 0.21 mg/l, p < 0.001). In multivariate analysis, the highest CysC tertile (>1.04 mg/l) was significantly associated with extracranial ICA stenosis (adjusted odds ratio [OR] 5.01, 95% confidence interval [CI] 1.51-16.63, p = 0.009) after adjustment for age, sex, diabetes, chronic kidney disease, current smoking, systolic blood pressure, HDL cholesterol, high-sensitivity C-reactive protein (hs-CRP) and premorbid lipid-lowering drugs use. When CysC was considered as a continuous variable, 1 SD increase in CysC was significantly associated with extracranial ICA stenosis (adjusted OR 3.01, 95% CI 1.58-5.72, p = 0.001). However, there were no significant associations between CysC levels and intracranial ICA/MCA stenosis. In addition, CysC levels showed a weak but statistically significant correlation with hs-CRP levels (r = 0.195, p = 0.021). Using receiver operating characteristic curve analysis, CysC value displayed good performance in discriminating extracranial ICA stenosis (c-statistic 0.79, 95% CI 0.69-0.89, p < 0.001).

Conclusions

This preliminary study suggests that higher levels of CysC were independently associated with symptomatic extracranial ICA stenosis, but not with intracranial ICA/MCA stenosis in patients with noncardioembolic stroke. Our findings provide new insights into the link between serum CysC and carotid atherosclerosis.

Neurological complications in chronic kidney disease patients

Chronic kidney disease (CKD) is associated with a high prevalence of cerebrovascular disorders such as stroke, white matter diseases, intracerebral microbleeds and cognitive impairment. This situation has been observed not only in end-stage renal disease patients but also in patients with mild or moderate CKD. The occurrence of cerebrovascular disorders may be linked to the presence of traditional and non-traditional cardiovascular risk factors in CKD. Here, we review current knowledge on the epidemiological aspects of CKD-associated neurological and cognitive disorders and discuss putative causes and potential treatment. CKD is associated with traditional (hypertension, hypercholesterolaemia, diabetes etc.) and non-traditional cardiovascular risk factors such as elevated levels of oxidative stress, chronic inflammation, endothelial dysfunction, vascular calcification, anaemia and uraemic toxins. Clinical and animal studies indicate that these factors may modify the incidence and/or outcomes of stroke and are associated with white matter diseases and cognitive impairment. However, direct evidence in CKD patients is still lacking. A better understanding of the factors responsible for the elevated prevalence of cerebrovascular diseases in CKD patients may facilitate the development of novel treatments. Very few clinical trials have actually been performed in CKD patients, and the impact of certain treatments is subject to debate. Treatments that lower LDL cholesterol or blood pressure may reduce the incidence of cerebrovascular diseases in CKD patients, whereas treatment with erythropoiesis-stimulating agents may be associated with an increased risk of stroke but a decreased risk of cognitive disorders. The impact of therapeutic approaches that reduce levels of uraemic toxins has yet to be evaluated.

Renal dysfunction is associated with deep cerebral microbleeds but not white matter hyperintensities in patients with acute intracerebral hemorrhage

Kidney disease is a risk factor for cerebral microangiopathy and spontaneous intracerebral hemorrhage (ICH). We aimed to determine the association of renal dysfunction (RD) with MRI correlates of different patterns of cerebral microangiopathies including cerebral microbleeds (CMB) and white matter lesions (WML) in patients with ICH. In a prospectively collected, single-center cohort of ICH patients, glomerular filtration rate (eGFR) was estimated using the Modification of Diet in Renal Disease equation. We classified the renal function in five categories: category 1 (eGFR ≥ 90 mL/min/1.73 m(2)), category 2 (eGFR 60-89), category 3 (eGFR 30-59), category 4 (eGFR 15-29), and category 5 (eGFR <15) and dichotomized at an eGFR of 60. Number, location, and extent of CMB and WML were measured on MRI. ICH and CMB locations were classified as lobar or deep. 97 ICH patients with MRI (mean age 65.9 ± 13.9 years) were included. Intracerebral hemorrhage was lobar in 52.6 %. Median eGFR was 85.8 mL/min/1.73 m(2) (IQR 34.3). Renal dysfunction was present in 12.4 % of the patients. At least one CMB was present in 57.7 % of patients, WML were even more frequent (97.7 %). Age and impaired renal function were factors independently associated with the presence of CMB. The presence of CMB was independently associated with the number and extent of WML. RD is a frequent comorbidity in patients with ICH. Associations of RD with hypertension and with CMB in deep location suggest a predominant impact of RD on deep rather than on lobar microangiopathy.

Chronic Kidney Disease in Patients With Lacunar Stroke: Association With Enlarged Perivascular Spaces and Total Magnetic Resonance Imaging Burden of Cerebral Small Vessel Disease

BACKGROUND AND PURPOSE

The relationship between chronic kidney disease and cerebral small vessel disease (cSVD), especially enlarged perivascular spaces (EPVS), has not been fully understood. This study aimed to investigate the association of chronic kidney disease and EPVS, as well as the total burden of cSVD on magnetic resonance imaging, expressed by the simultaneous presence of multiple markers of cSVD, among patients with first-ever lacunar stroke.

METHODS

Four hundred and thirteen consecutive patients were prospectively enrolled. Centrum semiovale and basal ganglia EPVS on T2-weighted magnetic resonance imaging, as well as other imaging markers of cSVD, including lacune, white matter lesions, and cerebral microbleeds, were rated using validated scales. Chronic kidney disease was defined as either reduced estimated glomerular filtration rate or the presence of proteinuria.

RESULTS

After adjustments for potential confounders by logistic regression, proteinuria and impaired estimated glomerular filtration rate were correlated with the severity of EPVS in both centrum semiovale (odds ratio [OR] 2.59; 95% confidence interval [CI] 1.19-5.64 and OR 2.37; 95% CI 1.19-4.73) and basal ganglia (OR 5.12; 95% CI 2.70-12.10 and OR 4.17; 95% CI 2.08-8.37). A similar association was also found between proteinuria and low estimated glomerular filtration rate levels and the comprehensive cSVD burden (OR 2.13; 95% CI 1.10-4.14 and OR 5.59; 95% CI 2.58-12.08).

CONCLUSIONS

Proteinuria and impaired estimated glomerular filtration rate are associated with increasing EPVS severity and, furthermore, accumulated magnetic resonance imaging burden of cSVD in patients with first-ever acute lacunar stroke.

Associations between biomarkers of renal function with cerebral microbleeds in hypertensive patients

BACKGROUND

Cerebral microbleeds (CMBs) have been observed in the elderly and have been regarded as a manifestation of small vessel disease (SVD). Cerebral and glomerular SVD may have a common source of pathogenesis because these organs are closely connected through anatomic and hemodynamic similarities. The purpose of this study was to clarify the associations between kidney biomarker levels and CMBs in hypertensive patients.

METHODS

The presence and number of CMBs were assessed on susceptibility-weighted imaging. We calculated the urinary albumin/creatinine ratio (UACR) from morning spot urine and the estimated glomerular filtration rate (eGFR) in serum samples. Serum cystatin C (CysC) was measured with an automated particle-enhanced turbidimetric immunoassay.

RESULTS

UACR and CysC levels were higher in the patients with CMBs than those without, and the eGFR was lower in the patients with CMBs than those without. A logistic regression analysis indicates that eGFR and UACR were independently associated with the prevalence of deep or infratentorial CMBs. The odds ratio (OR) (95% confidence interval (CI)) of eGFR and UACR was 1.95 (1.37-3.27) and 2.25 (1.66-4.46), respectively. CysC was independently associated with CMBs in both deep or infratentorial and lobar locations. The ORs (95% CI) were 2.59 (1.57-6.22) and 1.57 (1.15-4.85), respectively. Furthermore, CysC exhibited fair diagnostic value for CMBs, with an area under the curve of 0.80.

CONCLUSIONS

Kidney biomarker levels are associated with the presence of CMB in hypertensive patients without a history of transient ischemic attack (TIA) or stroke, independent of conventional risk factors, and CysC was a better marker for CMBs than eGFR and UACR.

Kidney function and cerebral small vessel disease in the general population

BACKGROUND

Anatomic and hemodynamic similarities between renal and cerebral vessels suggest a tight link between kidney disease and brain disease. Although several distinct markers are used to identify subclinical kidney and brain disease, a comprehensive assessment of how these markers link damage at both end organs is lacking.

AIM

To investigate whether measures of kidney function were associated with cerebral small vessel disease on MRI.

METHODS

In 2526 participants of the population-based Rotterdam Study, we measured urinary albumin-to-creatinine ratio, and estimated glomerular filtration rate based on serum creatinine and cystatin C. All participants underwent brain magnetic resonance imaging. We assessed presence of cerebral small vessel disease by calculating white matter lesion volumes and rating the presence of lacunes and cerebral microbleeds. We used multivariable linear and logistic regression to investigate the association between kidney function and cerebral small vessel disease.

RESULTS

Worse kidney function was consistently associated with a larger white matter lesion volume (mean difference per standard deviation increase in albumin-to-creatinine ratio: 0.09, 95% confidence interval 0.05; 0.12; per standard deviation decrease in creatinine-based estimated glomerular filtration rate: -0.04, 95% confidence interval -0.08;-0.01, and per standard deviation decrease in cystatin C-based estimated glomerular filtration rate: -0.09, 95% confidence interval -0.13;-0.05). Persons with higher albumin-to-creatinine ratio or lower cystatin C-based estimated glomerular filtration rate levels had a higher prevalence of lacunes (odds ratio per standard deviation increase in albumin-to-creatinine ratio: 1.24, 95% confidence interval 1.07; 1.43). Only participants in the highest quartile of albumin-to-creatinine ratio had a higher frequency of microbleeds compared to the lowest quartile.

CONCLUSIONS

Worse kidney function is associated with cerebral small vessel disease. Of all measures of kidney function, in particular albumin-to-creatinine ratio is related to cerebral small vessel disease.

Association of mild kidney dysfunction with silent brain lesions in neurologically normal subjects

Background

Chronic kidney disease (CKD) has been closely associated with stroke. Although a large number of studies reported the relationship between CKD and different types of asymptomatic brain lesions, few comprehensive analyses have been performed for all types of silent brain lesions.

Methods

We performed a cross-sectional study involving 1,937 neurologically normal subjects (mean age 59.4 years). Mild CKD was defined as an estimated glomerular filtration rate between 30 and 60 ml/min/1.73 m² or positive proteinuria.

Results

The prevalence of mild CKD was 8.7%. Univariate analysis revealed an association between CKD and all silent brain lesions, including silent brain infarction, periventricular hyperintensity, subcortical white matter lesion, and microbleeds, in addition to hypertension and diabetes mellitus after adjusting for age and sex. In binary logistic regression analysis, the presence of CKD was a significant risk factor for all types of silent brain lesions, independent of other risk factors.

Conclusions

These results suggest that mild CKD is independently associated with all types of silent brain lesions, even in neurologically normal subjects.

Association of kidney disease measures with ischemic versus hemorrhagic strokes: pooled analyses of 4 prospective community-based cohorts

BACKGROUND AND PURPOSE

Although low glomerular filtration rate (GFR) and albuminuria are associated with increased risk of stroke, few studies compared their contribution to risk of ischemic versus hemorrhagic stroke separately. We contrasted the association of these kidney measures with ischemic versus hemorrhagic stroke.

METHODS

We pooled individual participant data from 4 community-based cohorts: 3 from the United States and 1 from The Netherlands. GFR was estimated using both creatinine and cystatin C, and albuminuria was quantified by urinary albumin-to-creatinine ratio (ACR). Associations of estimated GFR and ACR were compared for each stroke type (ischemic versus intraparenchymal hemorrhagic) using study-stratified Cox regression.

RESULTS

Among 29,595 participants (mean age, 61 [SD 12.5] years; 46% men; 17% black), 1261 developed stroke (12% hemorrhagic) during 280,549 person-years. Low estimated GFR was significantly associated with increased risk of ischemic stroke, but not hemorrhagic stroke, whereas high ACR was associated with both stroke types. Adjusted hazard ratios for ischemic and hemorrhagic stroke at estimated GFR of 45 (versus 95) mL/min per 1.73 m2 were 1.30 (95% confidence interval, 1.01-1.68) and 0.92 (0.47-1.81), respectively. In contrast, the corresponding hazard ratios for ACR of 300 (versus 5) mg/g were 1.62 (1.27-2.07) for ischemic and 2.57 (1.37-4.83) for hemorrhagic stroke, with significantly stronger association with hemorrhagic stroke (P=0.04). For hemorrhagic stroke, the association of elevated ACR was of similar magnitude as that of elevated systolic blood pressure.

CONCLUSIONS

Whereas albuminuria showed significant association with both stroke types, the association of decreased estimated GFR was only significant for ischemic stroke. The strong association of albuminuria with both stroke types warrants clinical attention and further investigations.

Major bleeding in patients with atrial fibrillation receiving apixaban or warfarin: The ARISTOTLE Trial (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation): Predictors, Characteristics, and Clinical Outcomes

OBJECTIVES

This study sought to characterize major bleeding on the basis of the components of the major bleeding definition, to explore major bleeding by location, to define 30-day mortality after a major bleeding event, and to identify factors associated with major bleeding.

BACKGROUND

Apixaban was shown to reduce the risk of major hemorrhage among patients with atrial fibrillation in the ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) trial.

METHODS

All patients who received at least 1 dose of a study drug were included. Major bleeding was defined according to the criteria of the International Society on Thrombosis and Haemostasis. Factors associated with major hemorrhage were identified using a multivariable Cox model.

RESULTS

The on-treatment safety population included 18,140 patients. The rate of major hemorrhage among patients in the apixaban group was 2.13% per year compared with 3.09% per year in the warfarin group (hazard ratio [HR] 0.69, 95% confidence interval [CI]: 0.60 to 0.80; p < 0.001). Compared with warfarin, major extracranial hemorrhage associated with apixaban led to reduced hospitalization, medical or surgical intervention, transfusion, or change in antithrombotic therapy. Major hemorrhage followed by mortality within 30 days occurred half as often in apixaban-treated patients than in those receiving warfarin (HR 0.50, 95% CI: 0.33 to 0.74; p < 0.001). Older age, prior hemorrhage, prior stroke or transient ischemic attack, diabetes, lower creatinine clearance, decreased hematocrit, aspirin therapy, and nonsteroidal anti-inflammatory drugs were independently associated with an increased risk.

CONCLUSIONS

Apixaban, compared with warfarin, was associated with fewer intracranial hemorrhages, less adverse consequences following extracranial hemorrhage, and a 50% reduction in fatal consequences at 30 days in cases of major hemorrhage.