Elevated risk of stroke among patients with end-stage renal disease

Renal Disease and Neurology

PURPOSE OF REVIEW

Neurologic dysfunction is prevalent in patients with acute and chronic renal disease and may affect the central nervous system, peripheral nervous system, or both. Neurologic manifestations may result directly from the uremic state or as a consequence of renal replacement therapy. Early recognition of neurologic dysfunction may provide opportunities for intervention and reduced morbidity.

RECENT FINDINGS

Advances in the understanding of neurologic complications of renal disease and its treatments have led to more widespread recognition and earlier identification of encephalopathy syndromes such as cefepime neurotoxicity and posterior reversible encephalopathy syndrome (PRES), dramatic reductions in the incidence of dialysis disequilibrium syndrome and dialysis dementia, and improved survival in disorders such as von Hippel-Lindau disease and thrombotic thrombocytopenic purpura.

SUMMARY

This article summarizes the conditions that affect both the renal and the nervous systems, the effects of renal failure on the nervous system, and the neurologic complications of dialysis.

Temporal Trends in the Outcomes of Dialysis Patients Admitted With Acute Ischemic Stroke

BACKGROUND

There is a paucity of contemporary data on the characteristics and outcomes of acute ischemic stroke (AIS) in patients on maintenance dialysis.

METHODS AND RESULTS

We used the nationwide inpatient sample to examine contemporary trends in the incidence, management patterns, and outcomes of AIS in dialysis patients. A total of 930 010 patients were admitted with AIS between 2003 and 2014, of whom 13 642 (1.5%) were on dialysis. Overall, the incidence of AIS among dialysis patients decreased significantly (Ptrend<0.001), while it remained stable in non-dialysis patients (Ptrend=0.78). Compared with non-dialysis patients, those on dialysis were younger (67±13 years versus 71±15 years, P<0.001), and had higher prevalence of major comorbidities. Black patients constituted 35.2% of dialysis patients admitted with AIS compared with 16.7% of patients in the non-dialysis group (P<0.001). After propensity score matching, in-hospital mortality was higher in the dialysis group (7.6% versus 5.2%, P<0.001), but this mortality gap narrowed overtime (Ptrend<0.001). Hemorrhagic conversion and gastrointestinal bleeding rates were similar, but blood transfusion was more common in the dialysis group. Rates of severe disability surrogates (tracheostomy, gastrostomy, mechanical ventilation and non-home discharge) were also similar in both groups. However, dialysis patients had longer hospitalizations, and accrued a 25% higher total cost of acute care.

CONCLUSIONS

Dialysis patients have 8-folds higher incidence of AIS compared withnon-dialysis patients. They also have higher risk-adjusted in-hospital mortality, sepsis and blood transfusion, longer hospitalizations, and higher cost. There is a need to identify preventative strategies to reduce the risk of AIS in the dialysis population.

Atrial fibrillation in dialysis patients: is there a place for non-vitamin K antagonist oral anticoagulants?

Atrial fibrillation (AF) occurs approximately in 3% of general population, with greater prevalence in elderly. Non-vitamin K-dependent oral anticoagulant agents (NOACs) according to the current European guidelines are recommended for patients with AF at high risk for stroke as a first-choice treatment. NOACs are not inferior to warfarin or some of them are better than warfarin in reducing the rate of ischemic stroke. Moreover, they significantly reduce the rate of intracranial hemorrhages, major bleedings, and mortality compared with warfarin. Nevertheless according to ESC guidelines, NOACs are not recommended in patients with creatinine clearance < 30 mL/min. Observational studies provide contradictive data. Only few new trials are ongoing. Therefore, it is not clear if NOACs should be in the future prescribed to patients with advanced CKD and those on dialysis. Moreover, the risk of stroke and bleeding is much higher in such population than in patients without end-stage renal disease (ESRD). The authors provide data on pros and cons of use of NOACs in ESRD patients with AF.

Inequality in Care and Differences in Outcome Following Stroke in People With ESRD

Introduction

Stroke rate and mortality are greater in individuals with end-stage renal disease (ESRD) than in those without ESRD. We examined discrepancies in stroke care in ESRD patients and their influence on mortality.

Methods

This is a national record linkage cohort study of hospitalized stroke individuals from 2005 to 2013. Presentation, measures of care quality (admission to stroke unit, swallow assessment, antithrombotics, or thrombolysis use), and outcomes were compared in those with and without ESRD after propensity score matching (PSM). We examined the effect of being admitted to a stroke unit on survival using Kaplan-Meier and Cox survival analyses.

Results

A total of 8757 individuals with ESRD and 61,367 individuals with stroke were identified. ESRD patients (n =486) experienced stroke over 34,551.9 patient-years of follow-up; incidence rates were 25.3 (dialysis) and 4.5 (kidney transplant)/1000 patient-years. After PSM, dialysis patients were less likely to be functionally independent (61.4% vs. 77.7%; P < 0.0001) before stroke, less frequently admitted to stroke units (64.6% vs. 79.6%; P < 0.001), or to receive aspirin (75.3% vs. 83.2%; P = 0.01) than non-ESRD stroke patients. There were no significant differences in management of kidney transplantation patients. Stroke with ESRD was associated with a higher death rate during admission (dialysis 22.9% vs.14.4%, P = 0.002; transplantation: 19.6% vs. 9.3%; P = 0.034). Managing ESRD patients in a stroke unit was associated with a lower risk of death at follow-up (hazard ratio: 0.68; 95% confidence interval: 0.55-0.84).

Conclusion

Stroke incidence is high in ESRD. Individuals on dialysis are functionally more dependent before stroke and less frequently receive optimal stroke care. After a stroke, death is more likely in ESRD patients. Acute stroke unit care may be associated with lower mortality.

Primary outcomes of the Monitoring in Dialysis Study indicate that clinically significant arrhythmias are common in hemodialysis patients and related to dialytic cycle

Sudden death is one of the more frequent causes of death for hemodialysis patients, but the underlying mechanisms, contribution of arrhythmia, and associations with serum chemistries or the dialysis procedure are incompletely understood. To study this, implantable loop recorders were utilized for continuous cardiac rhythm monitoring to detect clinically significant arrhythmias including sustained ventricular tachycardia, bradycardia, asystole, or symptomatic arrhythmias in hemodialysis patients over six months. Serum chemistries were tested pre- and post-dialysis at least weekly. Dialysis procedure data were collected at every session. Associations with clinically significant arrhythmias were assessed using negative binomial regression modeling. Sixty-six patients were implanted and 1678 events were recorded in 44 patients. The majority were bradycardias (1461), with 14 episodes of asystole and only one of sustained ventricular tachycardia. Atrial fibrillation, although not defined as clinically significant arrhythmias, was detected in 41% of patients. With thrice-weekly dialysis, the rate was highest during the first dialysis session of the week and was increased during the last 12 hours of each inter-dialytic interval, particularly the long interval. Among serum and dialytic parameters, only higher pre-dialysis serum sodium and dialysate calcium over 2.5 mEq/L were independently associated with clinically significant arrhythmias. Thus, clinically significant arrhythmias are common in hemodialysis patients, and bradycardia and asystole rather than ventricular tachycardia may be key causes of sudden death in hemodialysis patients. Associations with the temporal pattern of dialysis suggest that modification of current dialysis practices could reduce the incidence of sudden death.

Association of dialysis with in-hospital disability progression and mortality in community-onset stroke

AIM

End-stage renal disease is associated with increased risk of cerebrovascular disease, but the effect on post-stroke clinical outcomes has not been thoroughly investigated.

METHODS

Using the Japanese Diagnosis Procedure Combination database, which includes administrative claims and discharge abstract data, we examined the association between risk factors including dialysis therapy and in-hospital disability progression or mortality in patients with community-onset stroke. We extracted data of patients aged ≥ 20 years old who were admitted to the hospital within 3 days after onset of stroke between July 2010 and March 2013. The disability level was divided into modified Rankin Scale (mRS) 0-1, 2-3, 4-5, and 6 (death). Disability progression was defined as an increase in disability level. Odds ratios for in-hospital disability progression and mortality were calculated using logistic regression models.

RESULTS

Of 435 403 patients, 7562 (1.7%) received dialysis therapy. The median length of stay was 21 and 20 days for patients with and without dialysis, respectively. During the hospital stay, disability progressed in 100 402 (23.1%) patients and 45 919 (10.5%) died. Patients on dialysis had a higher prevalence of disability progression (26.8%) and mortality (13.1%) compared to those without dialysis (23.0% and 10.5%, respectively). Dialysis was associated with an increased risk of in-hospital disability progression (odds ratio, 1.56; 95% confidence interval, 1.47-1.66) and mortality (odds ratio 1.70; 95% confidence interval, 1.57-1.84). These risks were comparable among subtypes of stroke.

CONCLUSIONS

Dialysis was associated with an increased risk of in-hospital disability progression and mortality among patients with community-onset stroke, regardless of stroke subtype.

Is anticoagulating haemodialysis patients with non-valvular atrial fibrillation too risky?

There is an increasing understanding of the risks from atrial fibrillation (AF) in the current era. In patients with end-stage renal disease (ESRD) on dialysis, the prevalence of AF is significantly higher compared to the general population and those with earlier stages of CKD. Although anticoagulation of these patients may seem appropriate, there is a lack of conclusive evidence that it provides the same protection from thromboembolic complications as it does in patients not on dialysis. In addition, the increased risk of bleeding in patients requiring dialysis makes the use of anticoagulants less favourable. This article aims to discuss the problem of AF in dialysis patients, summarise the current evidence around the use of oral anticoagulants for AF in ESRD and provide some practical suggestions on management of AF in the haemodialysis population.

Atrial Fibrillation Characteristics in Patients on Haemodialysis vs. Peritoneal Dialysis

Atrial fibrillation (AF) is highly prevalent in dialysis patients, however whether its impact differs between patients on haemodialysis (HD) vs. peritoneal dialysis (PD) is unknown. We aimed to compare the association of AF and clinical outcomes in different dialysis modalities. We performed a population based retrospective cohort study, including adult patients who initiated dialysis between the years 2002 and 2015. Clinical, echocardiographic and laboratory data were reviewed and correlated with outcomes in HD vs. PD. During the study period, 1,130 patients began dialysis. Of the 997 patients without AF before dialysis initiation, 17% developed new-onset AF after the initiation of dialysis (17.3% of HD vs. 13.7% of PD patients, p = 0.27). Using multivariate analysis, only enlarged left atrium at dialysis initiation (hazard ratio (HR) 2.82, CI95% 2.00–3.99) and age (HR 1.04, CI95% 1.03–1.06) were significantly associated with AF. Dialysis modality was not a significant predictor of AF in either univariate or multivariate analysis. In conclusion, our study demonstrated that AF is common in dialysis patients irrespective of modality. In our cohort, the risk factors associated with AF were older age and enlarged left atrium. AF was associated with increased rates of heart failure and mortality, but not stroke.

Qi Fu Yin-a Ming Dynasty Prescription for the Treatment of Dementia

The Traditional Chinese Medicine (TCM) theory that “kidneys give rise to marrow, and the brain is the sea of marrow” has been a guide for the clinical application of kidney, qi and blood tonics for prevention and treatment of dementia and improvement in memory. As low resistance end-organs, both the brain and the kidneys are subjected to blood flow of high volumes throughout the cardiac cycle. Alzheimer’s disease and vascular dementia are two common causes of dementia, and it is increasingly recognized that many older adults with dementia have both AD and vascular pathologies. The underlying molecular mechanisms are incompletely understood, but may involve atherosclerosis, vascular dysfunction, hypertension, type 2 diabetes, history of cardiac disease and possibly, kidney dysfuntion, leading to reduced erythropoietin production, anemia, brain energy deficit and slow excitotoxicity. During the Ming Dynasty, Zhang Jing-Yue used Qi Fu Yin (seven blessings decoction), comprising Panax ginseng, Rehmannia glutinosa, Angelica polymorpha, Atractylodes macrocephala, Glycyrrhiza uralensis, Ziziphus jujube, and Polygala tenuifolia to boost qi and blood circulation, strengthen the heart, and calm the spirit—skillfully linking heart, spleen, kidney, qi, blood and brain as a whole to treat age-related dementia. The purpose of this review is to outline TCM concepts for the treatment of dementia and illustrated with a historical prescription for the treatment of the condition, with the hope that this description may lead to advances in its management.

Long-term prognostic impact of anticoagulation on patients with atrial fibrillation undergoing hemodialysis

INTRODUCTION AND OBJECTIVES

Evidence for the efficacy and safety of oral anticoagulation with dicumarines in patients with atrial fibrillation (AF) on hemodialysis is controversial. The aim of our study is to evaluate the long-term prognostic implications of anticoagulation with dicumarines in a cohort of patients with non-valvular AF on a hemodialysis program due to end-stage renal disease.

METHODS

Retrospective, observational study with consecutive inclusion of 74 patients with AF on hemodialysis. The inclusion period was from January 2005 to October 2016. The primary variables were all-cause mortality, non-scheduled readmissions and bleeding during follow-up.

RESULTS

Mean age was 75±10 years; 66.2% were men and 43 patients (58.1%) received acenocoumarol. During a median follow-up of 2.40 years (IQR=0.88-4.15), acenocoumarol showed no survival benefit [HR=0.76, 95% CI (0.35-1.66), p=0.494]. However, anticoagulated patients were at increased risk of recurrent cardiovascular hospitalizations [IRR=3.94, 95% CI (1.06-14.69), p=0.041]. There was a trend towards an increase in repeated hospitalizations of ischemic cause in anticoagulated patients [IRR=5.80, 95% CI (0.86-39.0), p=0.071]. There was a statistical trend towards a higher risk of recurrent total bleeding in patients treated with acenocoumarol [IRR=4.43, 95% CI (0.94-20.81), p=0.059].

CONCLUSIONS

In this study, oral anticoagulation with acenocoumarol in patients with AF on hemodialysis did not increase survival. However, it was associated with an increased risk of hospitalizations of cardiovascular causes and a tendency to an increased risk of total bleeding.

Cardiovascular complications in chronic dialysis patients

PURPOSE OF REVIEW

This review article focuses on the most significant cardiovascular complications in dialysis patients [sudden cardiac death (SCD), acute coronary syndromes, heart failure, and atrial fibrillation].

RECENT FINDINGS

Current and ongoing research aims to quantify the rate and pattern of significant arrhythmia in dialysis patients and to determine the predominant mechanism of SCD. Preliminary findings from these studies suggest a high rate of atrial fibrillation and that bradycardia and asystole may be more frequent than ventricular arrhythmia as a cause of sudden death. A recently published matched cohort study in dialysis patients who received a defibrillator for primary prevention showed that there was no significant difference in mortality rates between defibrillator-treated patients and propensity-matched controls. Two randomized controlled trials are currently recruiting participants and will hopefully answer the question of whether implantable or wearable cardioverter defibrillators can prevent SCD. An observational study using United States Renal Data System data demonstrated how difficult it is to keep hemodialysis patients on warfarin, as more than two-thirds discontinued the drug during the first year. The ISCHEMIA-CKD trial may provide answers about the optimal strategy for the treatment of atherosclerotic coronary disease in patients with advanced chronic kidney disease.

SUMMARY

The article reviews the diagnosis of acute coronary syndromes in dialysis patients, current literature on myocardial revascularization, and data on fatal and nonfatal cardiac arrhythmia. The new classification of heart failure in end-stage renal disease is reviewed. Finally, available cohort studies on warfarin for stroke prevention in dialysis patients with atrial fibrillation are reviewed.

Stroke risk and outcomes in patients with chronic kidney disease or end-stage renal disease: Two nationwide studies

BACKGROUND AND AIMS

Because the risk and outcomes of stroke in patients with chronic kidney disease (CKD) or end-stage renal disease (ESRD) were unclear, we evaluated these risks using a retrospective cohort study and a nested cohort study.

METHODS

We used Taiwan's National Health Insurance Research Database to identify 1378 patients aged ≥20 years who had ESRD in 2000-2004. An age- and sex-matched CKD cohort (n = 5512) and a control cohort (n = 11,024) were selected for comparison. Events of incident stroke were considered as outcome during the follow-up period in 2000-2013, and we calculated adjusted hazard ratios (HR) and 95% CIs of stroke associated with CKD or ESRD. We further used matching procedure with propensity score to estimate the risk of stroke for control group, CKD patients, and EDRD patients. A nested cohort study of 318,638 hospitalized stroke patients between 2000 and 2010 also was conducted to analyze the impact of CKD and ESRD on post-stroke mortality.

RESULTS

Before propensity-score matching, the incidences of stroke for controls, CKD patients and ESRD patients were 6.57, 13.3, and 21.7 per 1000 person-years, respectively. Compared with control group, the adjusted HRs of stroke were 1.49 (95% CI, 1.32-1.68) and 2.39 (95% CI, 1.39-2.87) for people with CKD or ESRD respectively, and were significantly higher in both sexes and every age group. After propensity-score matching, the HRs of stroke for patients with CKD and ESRD were 1.51 (95% CI 1.24-1.85) and 2.08 (95% CI 1.32-3.26), respectively, during the follow-up period. Among hospitalized stroke patients, adjusted rate ratio (RR) of post-stroke mortality in CKD and ESRD cohorts were 1.44 (95% CI, 1.33-1.56) and 2.62 (95% CI, 2.43-2.82) respectively compared with control.

CONCLUSIONS

CKD and ESRD patient groups thus faced significantly higher risk of stroke and post-stroke mortality. Risk factor identification and preventive strategies are needed to minimize stroke risk and post-stroke mortality in these vulnerable patient groups.

Consequences of CKD on Functioning

Chronic kidney disease (CKD) is highly prevalent in the United States and throughout the world,(1) with approximately 13% of adults affected.(2) In addition, according to recent estimates, almost half of patients with CKD stages 3 to 5 are 70 years of age and older.(2) In the United States, the number of prevalent end-stage renal disease cases continues to increase in patients older than age 65. In light of the demographic characteristics of patients with CKD and ESRD, there has been considerable focus on associations between CKD and cardiovascular outcomes.(3) Until recently, less attention had been paid to other consequences of CKD in general and among older individuals with CKD in particular, but there is now solid evidence linking CKD with impairments of physical function, cognitive function, and emotional function and quality of life. This review summarizes available literature on these topics, focusing specifically on physical functioning and frailty, cognitive function, emotional health, including depression and anxiety, and health-related quality of life.

Malnutrition-inflammation is a risk factor for cerebral small vessel diseases and cognitive decline in peritoneal dialysis patients: a cross-sectional observational study

Background

Chronic kidney disease patients have an increased prevalence of subclinical cerebrovascular diseases. Dialysis patients have severe vascular diseases burden. The cerebral small vessel diseases (CSVD) are difficult to find by clinical assessment. The evaluation of CVSD needs MRI. Cognitive impairment is a consequence of CVSD which is diagnosed by cognitive testing. These limited the study of CVSD and cognitive function in dialysis patients. Peritoneal dialysis (PD) patients are minority of dialysis population. We know even fewer about the CVSD in this special population.

Methods

In this cross-sectional study, we enrolled 72 PD patients who received care at the Peking Union Medical College hospital peritoneal dialysis center. CSVD were assessed by brain MR images. Cognitive function was evaluated with the Chinese version of the MMSE and MoCA.

Results

In our PD patients, the brain MRI showed the prevalence different signs of CSVD were: lacunar infarcts 38.9%, microbleeds 36.1%, abnormal brain white matter hyperintensities (WMHs) 48.6%, and intracerebral hemorrhage 4.2%. 25% and 86.8%of our patients could be diagnosed as cognitive impairment, according to the MMSE and MoCA test, respectively. nPCR was lower in patients with a lacunar infarct or intracerebral hemorrhage, and relative to the MMSA/MoCA score; hsCRP was higher in patients with lacunar infarct or abnormal WMHs and negative relative to the MMSA/MoCA score. In logistic regression analyses, nPCR was an independent risk factor for lacunar infarcts and impaired cognitive function. The presence of lacunar infarct was an independent risk factor for cognitive function decline.

Conclusion

We demonstrated a high prevalence of CSVD and cognitive impairment in our PD patients. Lacunar infarct was the main kind of CVSD responsible for PD patients cognitive function decline. Our novel observation also revealed an association between malnutrition-inflammation and CSVD.

Electronic supplementary material

The online version of this article (10.1186/s12882-017-0777-1) contains supplementary material, which is available to authorized users.

Warfarin Use in Hemodialysis Patients With Atrial Fibrillation: A Systematic Review of Stroke and Bleeding Outcomes

Background:

Given the lack of clear indications for the use of warfarin in the treatment of atrial fibrillation (AF) in patients on hemodialysis and the potential risks that accompany warfarin use in these patients, we systematically reviewed stroke and bleeding outcomes in hemodialysis patients treated with warfarin for AF.

Objective:

To systematically review the stroke and bleeding outcomes associated with warfarin use in the hemodialysis population to treat AF.

Design:

Systematic review.

Setting:

All adult hemodialysis patients.

Patients:

Patients on hemodialysis receiving warfarin for the management of AF.

Measurements:

Any type of stroke and/or bleeding outcomes.

Methods:

MEDLINE(R) In-Process & Other Non-Indexed Citations and MEDLINE(R) via OVID (1946 to January 11, 2017), and EMBASE via OVID (1974 to January 11, 2017) were searched for relevant literature. Inclusion criteria were randomized controlled trials, observational studies, and case series in English that examined stroke and bleeding outcomes in adult population of patients (over 18 years old) who are on hemodialysis and taking warfarin for AF. Studies with less than 10 subjects, case reports, review articles, and editorials were excluded. Quality of selected articles was assessed using Newcastle-Ottawa Scale (NOS).

Results:

Of the 2340 titles and abstracts screened, 7 met the inclusion criteria. Two studies showed an association between warfarin use and an increased risk of stroke (Hazard Ratio: 1.93-3.36) but no association with an increased risk of bleed (HR: 0.85-1.04), while 4 studies showed no association between warfarin and stroke outcomes (HR: 0.12-1.17) but identified an association between warfarin and increased bleeding outcome (HR: 1.41-3.96). And 1 study reported neither beneficial nor harmful effects associated with warfarin use.

Limitations:

The major limitation to this review is that the 7 included studies were observational cohort studies, and thus the outcome measures were not specified and predetermined in a research protocol.

Conclusion:

Our systematic review demonstrated that for patients with AF who are on hemodialysis, warfarin was not associated with reduced outcomes of stroke but was rather associated with increased bleeding events.

Risk of Stroke in Elderly Dialysis Patients

Despite the current knowledge about the risk of stroke and its related factors in general population, this issue in elderly patients receiving dialysis remains unresolved. Firstly, to compare the risk of stroke between hemodialysis (HD) and peritoneal dialysis (PD), data on 13,065 incident dialysis patients (aged ≥ 65 years; 10,675 in HD and 2,390 in PD) were retrieved from the Korean Health Insurance dataset. Secondly, to identify the risk factors of stroke amongst various clinical and laboratory parameters in HD, 980 elderly patients were retrospectively analyzed using an independent prospective cohort from 31 dialysis centers. For a mean duration of 1.8 years (maximum of 5 years), the risk of all cardiovascular diseases (ischemic heart disease and stroke) did not differ between HD and PD. However, when analyses were conducted separately by subtype, the risk of stroke, not ischemic heart disease, was significantly higher in HD patients than in PD patients. When the risk factors of stroke were probed after HD for a mean duration of 2.6 years (maximum of 7 years), the absolute dependence on social support, a previous history of cardiovascular disease, high levels of low-density lipoprotein cholesterol, and the use of a high number of anti-hypertensive drugs were identified as being significant. Based on the discrepancy of stroke risk between modalities and the HD-tailored risk factors of stroke, the monitoring and management of these factors may be a key strategy to reduce the risk of stroke in elderly patients receiving dialysis.

Predicting in a predicament: Stroke and hemorrhage risk prediction in dialysis patients with atrial fibrillation

Whether to anticoagulate dialysis patients with atrial fibrillation is a common clinical dilemma with limited high-quality data to inform decision-making. While the efficacy and safety of anticoagulation for stroke prevention in dialysis patients with atrial fibrillation has long been debated and remains unclear, the more upstream issue of stroke risk assessment from atrial fibrillation has received relatively little attention. In the general population, a handful of risk scores to help predict stroke and hemorrhage risk in the setting of atrial fibrillation are widely validated and applied in clinical practice. But are they applicable to the dialysis population? The most commonly used stroke risk scores, CHADS2 and CHA2DS2-VASC, have limited validation in the dialysis population, and when validated, have shown poor performance (c-statistics <0.70). Stroke risk scores derived in the general atrial fibrillation population may perform poorly in dialysis patients for a number of reasons. Dialysis patients have unique stroke risk factors, such as chronic inflammation and vascular calcification, and a much higher competing risk of death, none of which are accounted for in current risk scores. Further complicating the dilemma of anticoagulation is hemorrhage risk, which is known to be exceedingly high in dialysis patients. Currently available hemorrhage risk scores, such as HAS-BLED, have not been validated in dialysis patients and will likely underestimate hemorrhage risk. Moving forward, risk tools specific to the dialysis population are needed to accurately assess and balance stroke and hemorrhage risks in dialysis patients with atrial fibrillation.

White matter damage in maintenance hemodialysis patients: a diffusion tensor imaging study

Background

Patients treated with dialysis have high rates of brain infarcts, brain atrophy, and white matter disease. There are limited data regarding the presence of more subtle damage to brain white matter.

Methods

In the Cognition and Dialysis Study, we compared brain structure using diffusion tensor imaging in hemodialysis (HD) patients to individuals without known kidney disease, using tract based spatial statistics (TBSS) to compare Fractional Anisotropy (FA) and Mean Diffusivity (MD). Statistical comparison of each overlaid voxel was age controlled using a permutation based corrected p value of <0.05.

Results

Thirty-four HD patients and twenty six controls (52 vs 51 years for HD vs control) had adequate magnetic resonance imaging for analysis. The HD group had fewer women (38% vs 23%) and a higher prevalence of diabetes (29% vs 8%), heart failure (29% vs 0%) and clinical stroke (15% vs 0%). Hemodialysis patients had significantly lower FA across multiple white matter fiber tracts, with fronto-temporal connections, the genu of the corpus callosum and the fornix more significantly affected than posterior regions of the brain. Similarly, HD patients had significantly higher mean diffusivity in multiple anterior brain regions. Results remained similar when those with a prior history of stroke were excluded.

Conclusions

In HD patients, there is more white matter disease in the anterior than posterior parts of the brain compared to controls without kidney disease. This pattern of injury is most similar to that seen in aging, suggesting that developing chronic kidney disease and ultimately kidney failure may result in a phenotype consistent with accelerated aging.

Myeloperoxidase Levels and Its Product 3-Chlorotyrosine Predict Chronic Kidney Disease Severity and Associated Coronary Artery Disease

BACKGROUND

The role of myeloperoxidase in chronic kidney disease (CKD) and its association with coronary artery disease (CAD) is controversial. In this study, we compared myeloperoxidase and protein-bound 3-chlorotyrosine (ClY) levels in subjects with varying degrees of CKD and tested their associations with CAD.

METHODS

From Clinical Phenotyping Resource and Biobank Core, 111 patients were selected from CKD stages 1 to 5. Plasma myeloperoxidase level was measured using enzyme-linked-immunosorbent assay. Plasma protein-bound 3-ClY, a specific product of hypochlorous acid generated by myeloperoxidase was measured by liquid chromatography mass spectrometry.

RESULTS

We selected 29, 20, 24, 22, and 16 patients from stages 1 to 5 CKD, respectively. In a sex-adjusted general linear model, mean ± SD of myeloperoxidase levels decreased from 18.1 ± 12.3 pmol in stage 1 to 10.9 ± 4.7 pmol in stage 5 (p = 0.011). In patients with and without CAD, the levels were 19.1 ± 10.1 and 14.8 ± 8.7 pmol (p = 0.036). There was an increase in 3-ClY mean from 0.81 ± 0.36 mmol/mol-tyrosine in stage 1 to 1.42 ± 0.41 mmol/mol-tyrosine in stage 5 (p < 0.001). The mean 3-ClY levels in patients with and without CAD were 1.25 ± 0.44 and 1.04 ± 0.42 mmol/mol-tyrosine (p = 0.023), respectively. C-statistic of ClY when added to myeloperoxidase level to predict CKD stage 5 was 0.86, compared to 0.79 for the myeloperoxidase level alone (p = 0.0097).

CONCLUSION

The myeloperoxidase levels decrease from stages 1 to 5, whereas activity increases. In contrast, both myeloperoxidase and ClY levels rise in the presence of CAD at various stages of CKD. Measuring both plasma myeloperoxidase and 3-CLY levels provide added value to determine the burden of myeloperoxidase-mediated oxidative stress.

Cognitive Function and Kidney Disease: Baseline Data From the Systolic Blood Pressure Intervention Trial (SPRINT)

BACKGROUND

Chronic kidney disease is common and is associated with cardiovascular disease, cerebrovascular disease, and cognitive function, although the nature of this relationship remains uncertain.

STUDY DESIGN

Cross-sectional cohort using baseline data from the Systolic Blood Pressure Intervention Trial (SPRINT).

SETTING & PARTICIPANTS

Participants in SPRINT, a randomized clinical trial of blood pressure targets in older community-dwelling adults with cardiovascular disease, chronic kidney disease, or high cardiovascular disease risk and without diabetes or known stroke, who underwent detailed neurocognitive testing in the cognition substudy, SPRINT-Memory and Cognition in Decreased Hypertension (SPRINT-MIND).

PREDICTORS

Urine albumin-creatinine ratio (ACR) and estimated glomerular filtration rate (eGFR).

OUTCOMES

Cognitive function, a priori defined as 5 cognitive domains based on 11 cognitive tests using z scores, and abnormal white matter volume quantified by brain magnetic resonance imaging.

RESULTS

Of 9,361 SPRINT participants, 2,800 participated in SPRINT-MIND and 2,707 had complete data; 637 had brain imaging. Mean age was 68 years, 37% were women, 30% were black, and 20% had known cardiovascular disease. Mean eGFR was 70.8±20.9mL/min/1.73m² and median urine ACR was 9.7 (IQR, 5.7-22.5) mg/g. In adjusted analyses, higher ACR was associated with worse global cognitive function, executive function, memory, and attention, such that each doubling of urine ACR had the same association with cognitive performance as being 7, 10, 6, and 14 months older, respectively. Lower eGFR was independently associated with worse global cognitive function and memory. In adjusted models, higher ACR, but not eGFR, was associated with larger abnormal white matter volume.

LIMITATIONS

Cross-sectional only, no patients with diabetes were included.

CONCLUSIONS

In older adults, higher urine ACR and lower eGFR have independent associations with global cognitive performance with different affected domains. Albuminuria concurrently identifies a higher burden of abnormal brain white matter disease, suggesting that vascular disease may mediate these relationships.

Antithrombotic therapy in end-stage renal disease

The delicate balance of risk vs. benefit of using antiplatelet and antithrombotic agents in the general population is well established. The decision to use these agents in the end stage renal disease (ESRD) population remains complex and difficult. The concomitant association of a prothombotic state with high risk of bleeding in the ESRD population requires individualization and careful clinical judgment before implementing such therapy. There remains a paucity of clinical trials and lack of substantial evidence in literature for safe and effective use of antithrombotic drugs in patients with advanced chronic kidney disease. The current review summarizes the pros and cons of using antiplatelet and antithrombotic agents in primary and secondary prevention of cardiovascular events, evaluate the risks with routine use of anticoagulation for cerebrovascular stroke prevention with nonvalvular atrial fibrillation and role of newer oral anticoagulants as alternate agents in the dialysis population.

Targeting the KEAP1-NRF2 System to Prevent Kidney Disease Progression

BACKGROUND

Nuclear factor erythroid 2-related factor 2 (NRF2) is a critical transcription factor for the antioxidative stress response and it activates a variety of cytoprotective genes related to redox and detoxification. NRF2 activity is regulated by the oxidative-stress sensor molecule Kelch-like ECH-associated protein 1 (KEAP1) that induces proteasomal degradation of NRF2 through ubiquitinating NRF2 under unstressed conditions. Because oxidative stress is a major pathogenic and aggravating factor for kidney diseases, the KEAP1-NRF2 system has been proposed to be a therapeutic target for renal protection.

SUMMARY

Oxidative-stress molecules, such as reactive oxygen species, accumulate in the kidneys of animal models for acute kidney injury (AKI), in which NRF2 is transiently and slightly activated. Genetic or pharmacological enhancement of NRF2 activity in the renal tubules significantly ameliorates damage related to AKI and prevents AKI progression to chronic kidney disease (CKD) by reducing oxidative stress. These beneficial effects of NRF2 activation highlight the KEAP1-NRF2 system as an important target for kidney disease treatment. However, a phase-3 clinical trial of a KEAP1 inhibitor for patients with stage 4 CKD and type-2 diabetes mellitus (T2DM) was terminated due to the occurrence of cardiovascular events. Because recent basic studies have accumulated positive effects of KEAP1 inhibitors in moderate stages of CKD, phase-2 trials have been restarted. The data from the ongoing projects demonstrate that a KEAP1 inhibitor improves the glomerular filtration rate in patients with stage 3 CKD and T2DM without safety concerns. Key Message: The KEAP1-NRF2 system is one of the most promising therapeutic targets for kidney disease, and KEAP1 inhibitors could be part of critical therapies for kidney disease.

ANMCO/AIAC/SICI-GISE/SIC/SICCH Consensus Document: percutaneous occlusion of the left atrial appendage in non-valvular atrial fibrillation patients: indications, patient selection, staff skills, organisation, and training

Atrial fibrillation (AF) is the most common arrhythmia and its prevalence is increasing due to the progressive aging of the population. About 20% of strokes are attributable to AF and AF patients are at five-fold increased risk of stroke. The mainstay of treatment of AF is the prevention of thromboembolic complications with oral anticoagulation therapy. Drug treatment for many years has been based on the use of vitamin K antagonists, but recently newer and safer molecules have been introduced (dabigatran etexilate, rivaroxaban, apixaban, and edoxaban). Despite these advances, many patients still do not receive adequate anticoagulation therapy because of contraindications (relative and absolute) to this treatment. Over the last decade, percutaneous closure of left atrial appendage, main site of thrombus formation during AF, proved effective in reducing thromboembolic complications, thus offering a valid medical treatment especially in patients at increased bleeding risk. The aim of this consensus document is to review the main aspects of left atrial appendage occlusion (selection and multidisciplinary assessment of patients, currently available methods and devices, requirements for centres and operators, associated therapies and follow-up modalities) having as a ground the significant evolution of techniques and the available relevant clinical data.

Cholesterol Levels Are Associated with 30-day Mortality from Ischemic Stroke in Dialysis Patients

BACKGROUND

We investigated the impact of serum cholesterol levels on 30-day mortality after ischemic stroke in dialysis patients.

METHODS

From the Taiwan Stroke Registry data, we identified 46,770 ischemic stroke cases, including 1101 dialysis patients and 45,669 nondialysis patients from 2006 to 2013.

RESULTS

Overall, the 30-day mortality was 1.46-fold greater in the dialysis group than in the nondialysis group (1.75 versus 1.20 per 1000 person-days). The mortality rates were 1.64, .62, 2.82, and 2.23 per 1000 person-days in dialysis patients with serum total cholesterol levels of <120 mg/dL, 120-159 mg/dL, 160-199 mg/dL, and ≥200 mg/dL, respectively. Compared to dialysis patients with serum total cholesterol levels of 120-159 mg/dL, the corresponding adjusted hazard ratios of mortality were 4.20 (95% confidence interval [CI] = 1.01-17.4), 8.06 (95% CI = 2.02-32.2), and 6.89 (95% CI = 1.59-29.8) for those with cholesterol levels of <120 mg/dL, 160-199 mg/dL, and ≥200 mg/dL, respectively.

CONCLUSIONS

Dialysis patients with serum total cholesterol levels of ≥160 mg/dL or <120 mg/dL on admission are at an elevated hazard of 30-day mortality after ischemic stroke.

Apixaban Pharmacokinetics at Steady State in Hemodialysis Patients

It is unclear whether warfarin is protective or harmful in patients with ESRD and atrial fibrillation. This state of equipoise raises the question of whether alternative anticoagulants may have a therapeutic role. We aimed to determine apixaban pharmacokinetics at steady state in patients on hemodialysis. Seven patients received apixaban 2.5 mg twice daily for 8 days. Blood samples were collected before and after apixaban administration on days 1 and 8 (nondialysis days). Significant accumulation of the drug was observed between days 1 and 8 with the 2.5-mg dose. The area under the concentration-time curve from 0 to 24 hours increased from 628 to 2054 ng h/ml (P<0.001). Trough levels increased from 45 to 132 ng/ml (P<0.001). On day 9, after a 2.5-mg dose, apixaban levels were monitored hourly during dialysis. Only 4% of the drug was removed. After a 5-day washout period, five patients received 5 mg apixaban twice daily for 8 days. The area under the concentration-time curve further increased to 6045 ng h/ml (P=0.03), and trough levels increased to 218 ng/ml (P=0.03), above the 90th percentile for the 5-mg dose in patients with preserved renal function. Apixaban 2.5 mg twice daily in patients on hemodialysis resulted in drug exposure comparable with that of the standard dose (5 mg twice daily) in patients with preserved renal function and might be a reasonable alternative to warfarin for stroke prevention in patients on dialysis. Apixaban 5 mg twice daily led to supratherapeutic levels in patients on hemodialysis and should be avoided.

Effects of stroke on changes in heart rate variability during hemodialysis

Background

Stroke and low heart rate variability (HRV) are both associated with an unfavorable prognosis in hemodialysis patients. The relationship between stroke and changes in HRV during hemodialysis remains unclear.

Methods

This study measured differences between predialysis and postdialysis HRV (△HRV) in 182 maintenance hemodialysis patients, including 30 patients with stroke, to assess changes in HRV during hemodialysis, and also to compare results to 114 healthy controls.

Results

All predialysis HRV measurements had no differences between stroke patients and those without stroke, but were lower than healthy controls. Postdialysis very low frequency (VLF) (P < 0.001), low frequency (LF) (P = 0.001), total power (TP) (P < 0.001) and the LF/high frequency (HF) ratio (P < 0.001) increased significantly relative to predialysis values in patients without stroke, whereas postdialysis HRV did not increase in stroke patients. After multivariate adjustment, dialysis vintage was negatively associated with △VLF (β = -0.698, P = 0.046), △LF (β = -0.931, P = 0.009), and △TP (β = -0.887, P = 0.012) in patients without stroke. Serum intact parathyroid hormone (β = -0.707, P = 0.019) was negatively associated with △LF. Total cholesterol (β = -0.008, P = 0.001) and high sensitivity C-reactive protein (β = -0.474, P = 0.012) were inversely correlated with the △LF/HF ratio in patients without stroke.

Conclusion

HRV in hemodialysis patients is lower than in the general population. Increase in △HRV was observed in hemodialysis patients without stroke but not in stroke patients. This result suggests suppressed autonomic nervous reactions against volume unloading during hemodialysis, which might contribute to unfavorable outcomes in hemodialysis patients but even more so in those with prior stroke. Nephrologists should notice the importance of △HRV especially in high-risk patients.

Loss of executive function after dialysis initiation in adults with chronic kidney disease

The association of dialysis initiation with changes in cognitive function among patients with advanced chronic kidney disease is poorly described. To better define this, we enrolled participants with advanced chronic kidney disease from the Chronic Renal Insufficiency Cohort in a prospective study of cognitive function. Eligible participants had a glomerular filtration rate of 20 ml/min/1.73m² or less, or dialysis initiation within the past two years. We evaluated cognitive function by a validated telephone battery at regular intervals over two years and analyzed test scores as z scores. Of 212 participants, 123 did not transition to dialysis during follow-up, 37 transitioned to dialysis after baseline, and 52 transitioned to dialysis prior to baseline. In adjusted analyses, the transition to dialysis was associated with a significant loss of executive function, but no significant changes in global cognition or memory. The estimated net difference in cognitive z scores at two years for participants who transitioned to dialysis during follow-up compared to participants who did not transition to dialysis was -0.01 (95% confidence interval -0.13, 0.11) for global cognition, -0.24 (-0.51, 0.03) for memory, and -0.33 (-0.60, -0.07) for executive function. Thus, among adults with advanced chronic kidney disease, dialysis initiation was associated with loss of executive function with no change in other aspects of cognition. Larger studies are needed to evaluate cognition during dialysis initiation.

Neurological consults on the renal unit

Neurological symptoms commonly occur in chronic kidney disease and may result from its treatments and complications. Impaired renal function also influences treatments for other neurological conditions, requiring various cautions, dose adjustments and timing considerations, particularly in the context of renal replacement therapy. In this review, we present six illustrative clinical vignettes to highlight these challenges.

Cognitive Decline and Its Risk Factors in Prevalent Hemodialysis Patients

BACKGROUND

Cognitive impairment is common in patients treated with hemodialysis. The trajectory of cognitive function and risk factors for cognitive decline remain uncertain in this population.

STUDY DESIGN

Longitudinal cohort.

SETTING & PARTICIPANTS

314 prevalent hemodialysis patients.

PREDICTORS

Age, sex, race, education level, hemodialysis vintage, cause of end-stage renal disease, and baseline history of cardiovascular disease.

OUTCOMES

Cognitive function as determined by a comprehensive neurocognitive battery, administered at baseline and yearly when possible. Individual cognitive test results were reduced into 2 domain scores using principal components analysis, representing memory and executive function, which were used as our coprimary outcomes and by definition have a mean of zero and SD of 1.

RESULTS

Mean age was 63 years; 54% were men, 22% were black, and 90% had at least a high school education. During a median follow-up of 2.1 (IQR, 0.9-4.2) years, 196 had at least 1 follow-up test, 156 died, and 43 received a kidney transplant. Linear mixed models and joint models, which accounted for competing risks from death, dropout, or kidney transplantation, showed nearly identical results. The joint model demonstrated a decline in executive function (-0.09 [95% CI, -0.13 to -0.05] SD per year), whereas memory improved slightly (0.05 [95% CI, 0.02 to 0.08] SD per year). A significant yearly decline was also seen in the Mini-Mental State Examination score (median change, -0.41; 95% CI, -0.57 to -0.25). Older age was the only significant risk factor for steeper executive function decline (-0.04 [95% CI, -0.06 to -0.02] SD steeper annual decline for each 10 years of age).

LIMITATIONS

Prevalent hemodialysis patients only, limited follow-up testing due to high mortality rate, and exclusion of participants with severe cognitive deficits or dementia.

CONCLUSIONS

Prevalent hemodialysis patients demonstrate significant cognitive decline, particularly within tests of executive function. Older age was the only statistically significant risk factor for steeper cognitive decline, which may have important clinical consequences for patient management and education. Future studies should evaluate strategies to maintain or improve cognitive function.

Association of Nonsteroidal Anti-inflammatory Drug Use With Stroke Among Dialysis Patients

Introduction

Limited studies have evaluated risk of stroke associated with the use of NSAIDs in patients with end-stage kidney disease. We examined the adverse effects of selective and nonselective NSAID use on the risk of stroke in dialysis patients.

Methods

A case-crossover study was conducted using medical claims data from the National Health Insurance Research Database in Taiwan. We identified patients with ischemic and hemorrhagic stroke (defined as International Classification of Diseases, 9th revision, Clinical Modification codes 433, 434, and 436 for ischemic stroke and 430 and 431 for hemorrhagic stroke) from inpatient claims during the period from 2003 to 2012. Conditional logistic regression models with adjustment for potential confounders were used to determine the effects of NSAID use on stroke.

Results

A total of 1190 dialysis patients with stroke were identified from 2003 to 2012. The results indicate a 1.31-fold increased risk of stroke related to NSAID use during the 30 days prior to a stroke (AOR = 1.31; 95% CI: 1.03–1.66); likewise, an excessive risk of ischemic stroke was observed (AOR = 1.34; 95% CI: 1.02–1.77). When classifying NSAIDs into selective and nonselective groups, nonselective NSAID use was significantly associated with an increased risk of stroke (AOR = 1.27; 95% CI: 1.00–1.61).

Discussion

In summary, the results show supportive evidence that NSAID use increased the risk of stroke in dialysis patients, which suggests the importance of closely monitoring the transient effects of initial NSAID treatment to patients on dialysis.

Prevalence of Atrial Fibrillation and Antithrombotic Therapy in Hemodialysis Patients: Cross-Sectional Results of the Vienna InVestigation of AtriaL Fibrillation and Thromboembolism in Patients on HemoDIalysis (VIVALDI)

Background

Atrial fibrillation (AF) adds significant risk of stroke and thromboembolism in patients on hemodialysis (HD). The aim of this study was to investigate the prevalence of AF in a population-based cohort of HD patients and practice patterns of antithrombotic therapy for stroke prevention in AF.

Methods

The Vienna InVestigation of AtriaL fibrillation and thromboembolism in patients on hemodialysis (VIVALDI), an ongoing prospective observational cohort study, investigates the prevalence of AF and the risk of thromboembolic events in HD patients in Vienna, Austria. We analyzed cross-sectional data of 626 patients (63.4% men, median age 66 years, approx. 73% of HD patients in Vienna), who provided informed consent. A structured interview with each patient was performed, recent and archived ECGs were viewed and medical histories were verified with electronic records.

Results

The overall prevalence of AF was 26.5% (166 patients, 71.1% men, median age 72 years) of which 57.8% had paroxysmal AF, 3.0% persistent AF, 32.5% permanent AF, and 6.6% of patients had newly diagnosed AF. The median CHA₂DS₂-VASc Score was 4 [25^th-75^th percentile 3–5]. In multivariable analysis, AF was independently associated with age (odds ratio: 1.05 per year increase, 95% confidence interval: 1.03–1.07), male sex (1.7, 1.1–2.6), history of venous thromboembolism (2.0, 1.1–3.6), congestive heart failure (1.7, 1.1–2.5), history of or active cancer (1.5, 1.0–2.4) and time on HD (1.08 per year on HD, 1.03–1.13). Antithrombotic treatment was applied in 84.4% of AF patients (anticoagulant agents in 29.5%, antiplatelet agents in 33.7%, and both in 21.1%). In AF patients, vitamin-K-antagonists were used more often than low-molecular-weight heparins (30.1% and 19.9%).

Conclusions

The prevalence of AF is high amongst HD patients and is associated with age, sex, and distinct comorbidities. Practice patterns of antithrombotic treatment indicate a lack of consensus for stroke prevention in HD patients with AF.

Stroke in Patients with Chronic Kidney Disease…: How do we Approach and Manage it?

Renal failure is a potent risk factor for stroke, which is a leading cause of morbidity and mortality worldwide. The risk of stroke is 5–30 times higher in patients with chronic kidney disease (CKD), especially on dialysis. Case fatality rates are also higher reaching almost 90%. It is therefore important to understand the factors that predispose to stroke in this vulnerable population to better apply preventive strategies. The heightened risk of stroke in CKD represents the interplay of the vascular co-morbidities that occur with renal impairment and factors specific to renal failure such as malnutrition-inflammation-atherosclerosis complex, the effect of uremic toxins, dialysis techniques, vascular access, and the use of anticoagulants to maintain flow in the extracorporeal circuit. Old age, hypertension, diabetes, and previous cerebrovascular disease are all risk factors for stroke with the period of dialysis initiation constituting the highest risk period for developing new stroke. Patients with CKD-stage 3–5 have worse survival and diminished functional outcomes following stroke. Thrombolytic therapy for stroke in CKD has shown an increased risk of symptomatic intracranial hemorrhage or serious systemic hemorrhage, and the therapeutic effects may be attenuated. Benefit of statin therapy in dialysis patient as preventive therapy has not been shown to be beneficial. Control of hypertension and the judicious use of antiplatelet agents form the mainstay of stroke prevention. The benefit of antiplatelet therapies and oral anticoagulants has to be balanced against the real and increased risk of bleeding that is most evident in dialysis cohorts. An increased risk of vascular calcification particularly intracerebral vascular calcification has been seen in patientsreceiving warfarin as prophylaxis in atrial fibrillation. Newer anticoagulants have not been tested in patients with glomerular filtration rate <30 ml/min and hence have to be used with caution. This article is a review of stroke in patients with CKD and approach to managing it.

Warfarin Initiation, Atrial Fibrillation, and Kidney Function: Comparative Effectiveness and Safety of Warfarin in Older Adults With Newly Diagnosed Atrial Fibrillation

BACKGROUND

The effectiveness and safety of warfarin use among patients with atrial fibrillation (AF) and reduced kidney function are uncertain.

STUDY DESIGN

Community-based retrospective cohort study (May 1, 2003, to March 31, 2012) using province-wide laboratory and administrative data in Alberta, Canada.

SETTING & PARTICIPANTS

14,892 adults 66 years or older with new AF and a measurement of kidney function. Long-term dialysis patients or kidney transplant recipients were excluded.

PREDICTOR

Propensity scores were used to construct a matched-pairs cohort of patients with AF who did and did not have a warfarin prescription within a 60-day period surrounding their AF diagnosis.

OUTCOMES

Within 1 year of initiating warfarin therapy (or the matched date for nonusers): (1) the composite of all-cause death, ischemic stroke, or transient ischemic attack (also assessed as separate end points) and (2) first hospitalization or emergency department visit for a major bleeding episode defined as an intracranial, upper or lower gastrointestinal, or other bleeding.

MEASUREMENTS

Baseline glomerular filtration rate (GFR) was estimated using the CKD-EPI creatinine equation. Patients were matched within estimated GFR (eGFR) categories: ≥90, 60 to 89, 45 to 59, 30 to 44, and <30mL/min/1.73m². Information for baseline characteristics (sociodemographics, comorbid conditions, and prescription drug use) was obtained.

RESULTS

Across eGFR categories, warfarin therapy initiation was associated with lower risk for the composite outcome compared to nonuse (adjusted HRs [95% CI] for eGFR categories ≥ 90, 60-89, 45-59, 30-44, and <30mL/min/1.73m²: 0.59 [0.35-1.01], 0.61 [0.54-0.70], 0.55 [0.47-0.65], 0.54 [0.44-0.67], and 0.64 [0.47-0.87] mL/min/1.73m², respectively). Compared to nonuse, warfarin therapy was not associated with higher risk for major bleeding except for those with eGFRs of 60 to 89mL/min/1.73m² (HR, 1.36; 95% CI, 1.13-1.64).

LIMITATIONS

Selection bias.

CONCLUSIONS

Among older adults with AF, warfarin therapy initiation was associated with a significantly lower 1-year risk for the composite outcome across all strata of kidney function. The risk for major bleeding associated with warfarin use was increased only among those with eGFRs of 60 to 89mL/min/1.73m².

Challenges managing end-stage renal disease and kidney transplantation in a child with MTFMT mutation and moyamoya disease

Moyamoya disease is a chronic cerebrovascular disorder with progressive stenosis. We describe a four-yr-old female with features of moyamoya disease referred to our center for kidney transplant evaluation with ESRD secondary to presumed renal dysplasia along with concern for cerebral vascular anomalies. With her constellation of organ involvement, a genetic workup revealed a homozygous, frameshift mutation in the mitochondrial methionyl-tRNA formyltransferase gene. Given her vascular anomalies and evidence of prior infarcts seen on cerebral imaging, it was felt that her risk of future stroke events was high and that hypotension or intravascular volume depletion would further exacerbate this risk. In hopes of improving her tenuous cerebral perfusion, she underwent a bilateral temporal craniotomy for superficial temporal artery to middle cerebral artery bypass. We highlight the challenges faced in a child with ESRD and kidney transplantation when cerebral vasculature is compromised. A multidisciplinary approach is critical in determining the need for a revascularization procedure prior to transplant and to help reduce the risk of ischemic or hemorrhagic events in this patient population.

Association of multiple ischemic strokes with mortality in incident hemodialysis patients: an application of multistate model to determine transition probabilities in a retrospective observational cohort

Background

Little is known about the effect of multiple, or subsequent, ischemic strokes in patients receiving hemodialysis.

Methods

We undertook a retrospective cohort study of incident hemodialysis patients with Medicare coverage who had experienced a first ischemic stroke. Factors associated with either a subsequent ischemic stroke or death following a first new stroke were modeled. A multistate model with Cox proportional hazards was used to predict transition probabilities from first ischemic stroke to either subsequent stroke or to death, and the demographic and clinical factors associated with the respective transition probabilities were determined. Effect of a subsequent ischemic stroke on survival was quantified.

Results

Overall, 12,054 individuals (mean age 69.7 years, 41.3 % male, 53.0 % Caucasian and 34.0 % African-American) experienced a first new ischemic stroke. Female sex was associated with an increased risk of having a subsequent ischemic stroke (adjusted hazard ratio 1.37, 95 % confidence intervals 1.20 – 1.56, P < 0.0001); African-Americans, as compared to Caucasians, had lower likelihood of dying after a first new ischemic stroke (0.81, 0.77 – 0.85, P < 0.0001). A subsequent stroke trended towards having a higher likelihood of transitioning to death compared to a first new ischemic stroke on dialysis (1.72, 0.96 – 3.09, P = 0.071). When a subsequent ischemic stroke occurs at 24 months, probability of survival dropped >15 %, in absolute terms, from 0.254 to 0.096, with substantial drops observed at subsequent time points such that the probability of survival was more than halved.

Conclusions

Likelihood of subsequent ischemic stroke and of survival in hemodialysis patients appears to vary by sex and race: females are more likely than males to experience a subsequent ischemic stroke, and Caucasians are more likely than African-Americans to die after a first new ischemic stroke. The risk of a transitioning to a subsequent stroke (after having had a first) increases until about 1 year, then decreases. Subsequent strokes are associated with decreased probability of survival, an effect which increases as time since first stroke elapses. This information may be of assistance to clinicians when counseling hemodialysis patients about the implications of recurrent ischemic stroke.

Cerebral blood flow changes in hemodialysis and peritoneal dialysis patients: an arterial-spin labeling MR imaging

We used arterial-spin labeling (ASL) MR imaging, a non-invasive technique to evaluate cerebral blood flow (CBF) changes in patients with end-stage renal disease (ESRD) undergoing peritoneal dialysis (PD) and hemodialysis (HD), and nondialysis ESRD patients compared with healthy cohort. Ninety seven ESRD patients including 32 PD patients (20 male, 12 female; mean age 33 ± 8 years), 33 HD patients (22 male, 11 female; mean age 33 ± 8 years) and 32 nondialysis patients (20 male, 12 female; mean age 35 ± 7 years) and 31 age- and gender-matched healthy controls (20 male, 11 female; mean age 32 ± 8 years) were included in this study. All subjects underwent ASL MR imaging, neuropsychologic tests, and ESRD patients underwent laboratory testing. CBF values were compared among PD, HD, nondialysis patients and control groups. Correlation analysis and multiple regression analysis were performed to investigate the association between CBF values and hemoglobin, neuropsychologic test results, serum creatinine, urea levels, disease duration, and dialysis duration. Elevated CBFs of whole brain region, gray matter, and white matter were found in all ESRD patient groups compared with healthy controls (all P < 0.001). However, compared with non-dialysis ESRD patients, both PD and HD patients had widespread regional CBF decline mainly in bilateral frontal and anterior cingulate cortices. There were no differences for CBF between PD and HD patient groups. Negative correlations were observed between mean CBFs of whole brain region, gray matter, and white matter and the hemoglobin level in all ESRD patients. Multiple linear regression showed elevated CBF of multiple brain areas correlated with some neuropsychological tests in ESRD patients (all P < 0.001, AlphaSim corrected), but the association was not present or shrank after adjusting hemoglobin level. This study found that mean CBF was predominantly increased in patients with ESRD, which correlated with their hemoglobin level and neurocognitive disorders. There were no differences of CBF change and cognitive function between PD and HD ESRD patients with long-term treatment. The degree of anemia may be a predominant risk factor for cognitive impairment in these ESRD patients.

A Systematic Review on the Efficacy of Amlodipine in the Treatment of Patients With Hypertension With Concomitant Diabetes Mellitus and/or Renal Dysfunction, When Compared With Other Classes of Antihypertensive Medication

The long-term cardiovascular (CV) effects of calcium channel blockers, with special focus on amlodipine, were compared with other classes of antihypertensive medications in high-risk hypertensive patient subgroups. A systematic literature review and meta-analysis was undertaken of 38 unique randomized, active-controlled, parallel-group trials comparing amlodipine/calcium channel blockers with diuretics, β-blockers, α-blockers, angiotensin-converting enzyme inhibitors, or angiotensin II receptor blockers, with ≥6-month follow-up, and which had included assessment of blood pressure (BP) and CV events [all-cause death, CV death, myocardial infarction (MI), stroke, congestive heart failure (CHF), or major CV events (MACE: MI, CHF, stroke, and CV death)], in hypertensive patients (baseline systolic/diastolic BP ≥140/≥90 mm Hg) with either concomitant diabetes and/or renal dysfunction. In hypertensive patients with diabetes, no difference was found for amlodipine versus comparators with respect to all-cause death, CV death, MACE, and MI; a decrease in stroke risk, and an increase in CHF risk, was seen. In hypertensive patients with renal dysfunction, no difference was found for amlodipine versus comparators with respect to all-cause death, CV death, MACE, MI, and CHF; a decrease in stroke risk was seen. Amlodipine was found to be at least as efficacious as all the other classes of antihypertensive agents in reducing systolic and diastolic BP. Long-term control of BP is critical for avoiding complications of hypertension in high-risk patients, particularly CV and cerebrovascular events such as stroke. This analysis has provided evidence that amlodipine is an appealing therapeutic option in the long-term management of hypertension in both diabetic and renal dysfunction patients.

Nitric oxide synthetic pathway and cGMP levels are altered in red blood cells from end-stage renal disease patients

Red blood cells (RBCs) enzymatically produce nitric oxide (NO) by a functional RBC-nitric oxide synthase (RBC-NOS). NO is a vascular key regulatory molecule. In RBCs its generation is complex and influenced by several factors, including insulin, acetylcholine, and calcium. NO availability is reduced in end-stage renal disease (ESRD) and associated with endothelial dysfunction. We previously demonstrated that, through increased phosphatidylserine membrane exposure, ESRD-RBCs augmented their adhesion to human cultured endothelium, in which NO bioavailability decreased. Since RBC-NOS-dependent NO production in ESRD is unknown, this study aimed to investigate RBC-NOS levels/activation, NO production/bioavailability in RBCs from healthy control subjects (C, N = 18) and ESRD patients (N = 27). Although RBC-NOS expression was lower in ESRD-RBCs, NO, cyclic guanosine monophosphate (cGMP), RBC-NOS Serine1177 phosphorylation level and eNOS/Calmodulin (CaM)/Heat Shock Protein-90 (HSP90) interaction levels were higher in ESRD-RBCs, indicating increased enzyme activation. Conversely, following RBCs stimulation with insulin or ionomycin, NO and cGMP levels were significantly lower in ESRD- than in C-RBCs, suggesting that uremia might reduce the RBC-NOS response to further stimuli. Additionally, the activity of multidrug-resistance-associated protein-4 (MRP4; cGMP-membrane transporter) was significantly lower in ESRD-RBCs, suggesting a possible compromised efflux of cGMP across the ESRD-RBCs membrane. This study for the first time showed highest basal RBC-NOS activation in ESRD-RBCs, possibly to reduce the negative impact of decreased NOS expression. It is further conceivable that high NO production only partially affects cell function of ESRD-RBCs maybe because in vivo they are unable to respond to physiologic stimuli, such as calcium and/or insulin.

Warfarin Use and Risk of Stroke in Patients With Atrial Fibrillation Undergoing Hemodialysis: A Meta-Analysis

In spite of the substantial burden of atrial fibrillation and associated elevated ischemic stroke risk in patients undergoing hemodialysis, the role of warfarin in these high-risk patients remains uncertain. Our objective was to clarify the association between warfarin use and risk of stroke for patients with atrial fibrillation undergoing dialysis.PubMed and Embase from January 1966 to January 2015 were searched to identify relevant studies. Inclusion criteria were cohort studies, patients with atrial fibrillation undergoing hemodialysis, and reported quantitative estimates of the multivariate adjusted relative risk (RR) and 95% confidence interval (CI) for future stroke associated with warfarin use. We identified 8 studies, with a total of 9539 participants and 706 stroke events. Three studies reported total stroke as primary endpoint and other studies reported ischemic stroke as primary endpoint. Pooling the results showed that warfarin use was associated with higher risk of any stroke (RR 1.50, 95% CI: 1.13-1.99). By stroke type, warfarin was not significantly linked to risk of ischemic stroke (RR 1.01, 95% CI: 0.65-1.57, P = 0.97), but was related to greater hemorrhagic stroke risk (RR 2.30, 95% CI: 1.62-3.27). Warfarin heightened overall bleeding risk (RR 1.27, 95% CI: 1.03-1.56), but not death (RR 0.67, 95% CI: 0.37-1.21).Among patients with atrial fibrillation undergoing hemodialysis, use of warfarin is associated with a higher risk of hemorrhagic stroke, but did not increase overall mortality.

Retinal Artery Occlusion and the Risk of Stroke Development: Twelve-Year Nationwide Cohort Study

BACKGROUND AND PURPOSE

Our aim was to evaluate the risk of subsequent stroke development after retinal artery occlusion (RAO).

METHODS

National registry data were collected from the Korean National Health Insurance Service, comprised 1 025 340 random subjects. Patients diagnosed with RAO in 2002 and 2003 were excluded. The RAO group was composed of patients with an initial diagnosis of either central or other RAO between January 2004 and December 2013 (n=401). The comparison group was composed of randomly selected patients (5 per RAO patient; n=2003) who were matched to the RAO group according to sociodemographic factors and year of RAO diagnosis. Each sampled patient was tracked until 2013. Cox proportional hazard regression was used.

RESULTS

Stroke occurred in 15.0% of the RAO group and in 8.0% of the comparison group (P < 0.001). RAO was associated with an increased risk of stroke occurrence (hazard ratio, 1.78; 95% confidence interval, 1.32-2.41). The magnitude of the RAO effect for stroke was larger among younger adults aged <65 years (hazard ratio, 3.11) than older adults aged ≥65 years (hazard ratio, 1.26). However, the risk of subsequent stroke was significantly increased in older adults aged ≥65 years at the 4-year follow-up (hazard ratio, 1.58; 95% confidence interval, 1.01-2.48).

CONCLUSIONS

RAO was significantly associated with subsequent stroke after adjusting for comorbidities and sociodemographic factors. These findings are limited by uncontrolled confounding factors and need to be replicated by other observational studies.