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

Cognitive function among hemodialysis patients in Japan

BACKGROUND

Over 290,000 patients are undergoing hemodialysis (HD) in Japan. With old age, the odds of undergoing HD treatment sharply increase, as does the prevalence of cognitive impairment. The aim of the present work was to assess cognitive impairment in HD patients and its relation to clinical characteristics.

METHODS

Using a cross-sectional design, we administered the Mini-Mental State Examination (MMSE) to 154 HD outpatients and 852 participants from the Iwaki Health Promotion Project 2010, representing the general population.

RESULTS

The prevalence of cognitive impairment based on the MMSE was 18.8% in HD patients. HD patients showed a higher prevalence of cognitive impairment in older groups (50 years and older). In a logistic regression model with age, gender and amount of education as covariates, undergoing HD was a significant independent factor (OR = 2.28, 95% CI 1.33 to 3.94) associated with a lower MMSE score. Among HD patients, we found that level of education was associated with MMSE score.

CONCLUSIONS

There is a high prevalence of cognitive impairment among HD patients that has adverse implications for hospitalization and shortens their life expectancy. HD treatment was an independent risk factor for cognitive impairment. Clinicians should carefully monitor and treat cognitive impairment in HD patients. Further studies are required to determine the reasons for cognitive impairment in HD patients.

Cardiovascular disease and cognitive function in maintenance hemodialysis patients

BACKGROUND

Cardiovascular disease (CVD) and cognitive impairment are common in dialysis patients. Given the proposed role of microvascular disease on cognitive function, particularly cognitive domains that incorporate executive functions, we hypothesized that prevalent systemic CVD would be associated with worse cognitive performance in hemodialysis patients.

DESIGN

Cross-sectional cohort.

SETTING & PARTICIPANTS

200 maintenance hemodialysis patients without prior stroke from 5 Boston-area hemodialysis units.

PREDICTOR

CVD, defined as history of coronary disease or peripheral vascular disease.

OUTCOME

Performance on a detailed neurocognitive battery. Primary analyses quantified cognitive performance using principal components analysis to reduce cognitive tests to a processing speed/executive function domain and a memory domain. Multivariable linear regression models adjusted for age, sex, education, race, and other clinical and demographic characteristics.

RESULTS

Mean age of participants was 62 ± 18 (standard deviation) years and 75 (38%) had CVD. Individuals with CVD were older and more likely to be men, have diabetes, and be current or former smokers. In adjusted models, individuals with CVD performed 0.50 standard deviation worse (P < 0.001) on tests assessing processing speed/executive function, whereas there was no difference in performance on tests of memory. Similar results were seen assessing individual tests, with performance on the Block Design, Digit Symbol Coding, and Trail Making Tests A and B significantly associated with CVD in age-, sex-, education-, and race-adjusted analyses and approaching significance in fully adjusted models.

LIMITATIONS

CVD ascertainment dependent on patient recall and dialysis unit documentation. No brain imaging.

CONCLUSIONS

The presence of CVD is associated with worse cognitive performance on tests of processing speed and executive functioning in hemodialysis patients and identifies a high-risk population for greater difficulty with complex tasks.

Cardiovascular disease in chronic kidney disease. A clinical update from Kidney Disease: Improving Global Outcomes (KDIGO)

Cardiovascular morbidity and mortality in patients with chronic kidney disease (CKD) is high, and the presence of CKD worsens outcomes of cardiovascular disease (CVD). CKD is associated with specific risk factors. Emerging evidence indicates that the pathology and manifestation of CVD differ in the presence of CKD. During a clinical update conference convened by the Kidney Disease: Improving Global Outcomes (KDIGO), an international group of experts defined the current state of knowledge and the implications for patient care in important topic areas, including coronary artery disease and myocardial infarction, congestive heart failure, cerebrovascular disease, atrial fibrillation, peripheral arterial disease, and sudden cardiac death. Although optimal strategies for prevention, diagnosis, and management of these complications likely should be modified in the presence of CKD, the evidence base for decision making is limited. Trials targeting CVD in patients with CKD have a large potential to improve outcomes.

Traditional and nontraditional risk factors as predictors of cerebrovascular events in patients with end stage renal disease

OBJECTIVES AND METHODS

End stage renal disease (ESRD) patients exhibit a higher risk of cerebrovascular events as compared with the general population. In 283 ESRD patients followed up for 10 years, we investigated the long-term predictive value for stroke and transient ischemic attacks of traditional and nontraditional risk factors. Data analysis was performed by a modified Cox regression analysis for repeated events and by a competing risks analysis.

RESULTS

During the follow-up, 61 cerebrovascular events occurred in 47 patients. On univariate Cox analysis, the risk of cerebrovascular outcomes was directly related to age, smoking, diabetes, BMI, systolic and pulse pressures, triglycerides, hemoglobin, history of stroke/transient ischemic attacks, arrhythmia and left ventricular mass index. Nontraditional risk factors in ESRD such as norepinephrine, homocysteine, interleukin-6 and asymmetric dimethylarginine failed to predict these events. In a multivariate Cox model for repeated events only smoking [hazard ratio: 2.45, 95% confidence interval (CI): 1.29-4.65], age (hazard ratio: 1.05, 95% CI: 1.01-1.08), hemoglobin (hazard ratio: 1.28, 95% CI 1.06-1.54), triglycerides (hazard ratio: 1.04, 95% CI 1.01-1.08), pulse pressure (hazard ratio: 1.53, 95% CI 1.01-2.23) and left ventricular mass index (hazard ratio: 1.02, 95% CI 1.01-1.04) maintained an independent relationship with cerebrovascular events. The direct link between hemoglobin and cerebrovascular events was significantly stronger (P < 0.05) than that of the same variable and death.

CONCLUSION

The risk of stroke in ESRD depends mainly on traditional risk factors, high hemoglobin and left ventricular hypertrophy. Multiple interventions aimed to reduce arterial stiffness, left ventricular mass and smoking as well as to maintain hemoglobin within the recommended therapeutic range may have beneficial effects on the risk of cerebrovascular events in ESRD patients.

Inflammatory markers and risk of cerebrovascular events in patients initiating dialysis

BACKGROUND AND OBJECTIVES

Stroke remains a leading cause of morbidity and mortality for patients on dialysis; however, its risk factors in this population and measures to prevent it are not well understood.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We investigated whether inflammation was associated with cerebrovascular events in a national US cohort of 1041 incident dialysis patients enrolled from October 1995 to June 1998 and followed until January 31, 2004. Incident cerebrovascular events were defined as nonfatal (hospitalized stroke, carotid endarterectomy) and fatal (stroke death) events after dialysis initiation. With Cox proportional hazards regression analysis accounting for the competing risk of nonstroke death, we assessed the independent event risk associated with baseline levels of multiple inflammatory markers (high-sensitivity C-reactive protein [hsCRP], interleukin-6 (IL-6), matrix metalloproteinase-3 [MMP-3], and P-selectin) and hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor (statin) use, which may have pleiotropic inflammatory effects.

RESULTS

165 patients experienced a cerebrovascular event during 3548 person-years of follow-up; overall incidence rate was 4.9/100 person-years. None of the inflammatory markers were associated with cerebrovascular event risk (adjusted hazard ratios [HRs] per log unit [95% confidence interval]: hsCRP, 0.97 [0.85 to 1.11]; IL-6, 1.04 [0.85 to 1.26]; MMP-3, 1.02 [0.70 to 1.48]; P-selectin, 0.98 [0.57 to 1.68]). Statin use was also not associated with significant risk of events in unadjusted (HR 1.07 [0.69 to 1.68]) or propensity-score adjusted analyses (HR 0.98 [0.61 to 1.56]).

CONCLUSIONS

In conclusion, neither inflammatory markers nor statin use was associated with risk of cerebrovascular events. Further studies are needed to understand the pathophysiology and prevention of stroke in patients on dialysis.

Factors affecting outcome of intracerebral hemorrhage in patients undergoing chronic hemodialysis

To date, despite a markedly high incidence of intracerebral hemorrhage (ICH) in patients with end-stage renal disease, only few studies have focused on factors that affect patient's prognosis. To elucidate these factors, we retrospectively investigated 22 consecutive patients who had chronic renal failure, were maintained by hemodialysis (HD), had suffered from ICH, and were hospitalized and treated in our institute from 2006 to 2008. Hematoma volume, blood pressure on admission, blood pressure 3 days after ICH onset, and neurological deterioration significantly affected patient mortality. Progression of neurological symptoms during HD was observed often in patients with hematoma of more than 60 mL or in patients with pontine hemorrhages. Age, gender, duration of HD, anti-platelet or anticoagulant therapies, or maximal dose of nicardipine did not affect patient's prognosis. Based on this study we conclude that controlling blood pressure on admission and within 3 days after onset of ICH may be the most important factor that would improve patient's prognosis. Further, special care might be required for patients with large hematomas (more than 60 mL) or those with brainstem hemorrhages, because progression of neurological symptoms occurs often in such patients.

Warfarin in haemodialysis patients with atrial fibrillation: what benefit?

Warfarin is commonly used to prevent stroke in patients with atrial fibrillation; however, patients on haemodialysis may not derive the same benefit from warfarin as the general population. There are no randomized controlled studies in dialysis patients which demonstrate the efficacy of warfarin in preventing stroke. In fact, warfarin places the dialysis patient at increased risk for haemorrhagic stroke and possibly ischaemic stroke. Additionally, warfarin increases the risk of major bleeding and has been associated with vascular calcification. Routine use of warfarin in dialysis for stroke prevention should be discouraged, and therapy should only be reserved for dialysis patients at high risk for thrombo-embolic stroke and carefully monitored if implemented.

[Cognitive impairment and chronic kidney disease: which links?]

Ageing of the population leads to an increase of cognitive disorders and chronic renal failure incidence. Compared to the general population, prevalence of cognitive impairment is more important in renal failure patients, especially in dialyzed patients. No direct link has been established between renal failure and cognitive impairment. The care of older and older patients and the high frequency of vascular risk factors, in particular hypertension and diabetes, partially explain the prevalence of vascular dementia and Alzheimer disease in this population. Other factors as the anemia, phosphocalcic metabolism disorders facilitate the cognitive impairment. The present work reviews the links existing between chronic renal failure and cognitive impairment.

Anemia and chronic kidney disease are potential risk factors for mortality in stroke patients: a historic cohort study

Background

Chronic kidney disease (CKD) is associated to a higher stroke risk. Anemia is a common consequence of CKD, and is also a possible risk factor for cerebrovascular diseases. The purpose of this study was to examine if anemia and CKD are independent risk factors for mortality after stroke.

Methods

This historic cohort study was based on a stroke registry and included patients treated for a first clinical stroke in the stroke unit of one academic hospital over a three-year period. Mortality predictors comprised demographic characteristics, CKD, glomerular filtration rate (GFR), anemia and other stroke risk factors. GFR was estimated by means of the simplified Modification of Diet in Renal Disease formula. Renal function was assessed according to the Kidney Disease Outcomes Quality Initiative (K/DOQI)-CKD classification in five groups. A value of hemoglobin < 120 g/L in women and < 130 g/L in men on admission defined anemia. Kaplan-Meier survival curves and Cox models were used to describe and analyze one-year survival.

Results

Among 890 adult stroke patients, the mean (Standard Deviation) calculated GFR was 64.3 (17.8) ml/min/1.73 m² and 17% had anemia. Eighty-two (10%) patients died during the first year after discharge. Among those, 50 (61%) had K/DOQI CKD stages 3 to 5 and 32 (39%) stages 1 or 2 (p < 0.001). Anemia was associated with an increased risk of death one year after discharge (p < 0.001). After adjustment for other factors, a higher hemoglobin level was independently associated with decreased mortality one year after discharge [hazard ratio (95% CI) 0.98 (0.97-1.00)].

Conclusions

Both CKD and anemia are frequent among stroke patients and are potential risk factors for decreased one-year survival. The inclusion of patients with a first-ever clinical stroke only and the determination of anemia based on one single measure, on admission, constitute limitations to the external validity. We should investigate if an early detection and management of both CKD and anemia could improve survival in stroke patients.

Interleukin-6 and silent cerebral infarction in hemodialysis patients: a cross-sectional study

BACKGROUND

In patients with chronic renal failure undergoing hemodialysis (HD), silent cerebral infarctions (SCI) are associated with high mortality. Levels of interleukin-6 (IL-6) increase with renal dysfunction and may be a novel predictor for cerebrovascular events. We tested the hypothesis that increased IL-6 levels correlate with the occurrence of SCI in HD patients.

METHODS

Using cranial magnetic resonance imaging findings, we divided 50 Japanese patients undergoing HD into two groups: with SCI (60 ± 7 years, mean ± SD, n = 27) and without SCI (60 ± 6 years, n = 23). We compared the gender, body mass index, metabolic profiles, IL-6 levels, and smoking habits between the two groups.

RESULTS

We made the following observations: (i) The prevalence of diabetes or hypertension did not differ between the two groups, (ii) the level of IL-6 was higher in the with-SCI group than in the without-SCI group (P < 0.0001), (iii) the proportion of smokers was higher in the with-SCI group (P < 0.05), (iv) plasma level of high-density lipoprotein cholesterol was lower, whilst uric acid level was higher, in the with-SCI group (P < 0.05 and P < 0.05, respectively), and (v) multiple logistic regression analysis identified IL-6 levels as being significantly associated with the presence of SCI (odds ratio 3.13, 95% CI = 1.42-7.89, P < 0.0001).

CONCLUSIONS

This study indicates that patients with chronic renal failure who are maintained on HD exhibit an increased prevalence of SCI and that IL-6 is significantly associated with the presence of SCI in HD patients.

Polyclonal light chains in cerebrovascular disease

Altered membrane permeability is a hallmark of inflammation and ischemia with systemic spreading. Renal dysfunction is a risk factor for cardiovascular, cerebrovascular, and metabolic diseases. The aim of the present study was to assess proteinuria and urinary polyclonal light chains in acute stroke and chronic cerebrovascular disease compared with other neurologic diseases. Our results showed significantly increased levels of urinary polyclonal light chains in cerebrovascular disease compared with other neurologic diseases. The highest values of urinary polyclonal κ chains were found in acute stroke compared with chronic cerebrovascular disease and other neurologic diseases, while the level of λ chains was mainly increased in chronic cerebrovascular diseases. The shift to chronic renal failure seems to be signaled by a decreased polyclonal light chain/creatinemia ratio. The absence of a significant correlation with blood pressure and other seric parameters suggests that polyclonal light chains are an early marker of reversible vascular impairment with renal dysfunction before progression to irreversible renal failure and need for dialysis and/or intensive care.

Successful thrombolysis for acute ischaemic stroke in haemodialysis

Stroke is a leading cause of death worldwide and is associated with significant morbidity in survivors. Early thrombolytic therapy in acute ischaemic stroke has been shown to dramatically improve patient outcomes. Although the age-adjusted incidence of stroke is 5–10 times greater in haemodialysis patients, the use of thrombolysis for this indication in this group of patients has not been described to date. We present a case where alteplase was used successfully for acute ischaemic stroke in a patient established on maintenance haemodialysis in the setting of an international randomized controlled trial and advocate caution with the use of systemic thrombolytics despite the favourable outcome seen with this case.

Primary care of the renal transplant patient

There has been a remarkable rise in the number of kidney transplant recipients (KTR) in the US over the last decade. Increasing use of potent immunosuppressants, which are also potentially diabetogenic and atherogenic, can result in worsening of pre-existing medical conditions as well as development of post-transplant disease. This, coupled with improving long-term survival, is putting tremendous pressure on transplant centers that were not designed to deliver primary care to KTR. Thus, increasing numbers of KTR will present to their primary care physicians (PCP) post-transplant for routine medical care. Similar to native chronic kidney disease patients, KTRs are vulnerable to cardiovascular disease as well as a host of other problems including bone disease, infections and malignancies. Deaths related to complications of cardiovascular disease and malignancies account for 60-65% of long-term mortality among KTRs. Guidelines from the National Kidney Foundation and the European Best Practice Guidelines Expert Group on the management of hypertension, dyslipidemia, smoking, diabetes and bone disease should be incorporated into the long-term care plan of the KTR to improve outcomes. A number of transplant centers do not supply PCPs with protocols and guidelines, making the task of the PCP more difficult. Despite this, PCPs are expected to continue to provide general preventive medicine, vaccinations and management of chronic medical problems. In this narrative review, we examine the common medical problems seen in KTR from the PCP's perspective. Medical management issues related to immunosuppressive medications are also briefly discussed.

Neuropsychiatric complications of chronic kidney disease

Evidence is emerging that cognitive impairment, delirium and depression are very common in patients with renal disease. All of these conditions are associated with prolonged hospitalization and an increased risk of mortality. A good understanding of these conditions is key to their prevention, early intervention and management. This Review summarizes the clinical features of various forms of cognitive dysfunction that occur in individuals with renal disease and describes the evidence for the high burden of disease in such patients.

“Does chronic kidney disease define a particular risk pattern of cerebral vessels modifications in patients with symptomatic ischemic cerebrovascular disease?”

Cardiovascular complications, including stroke, may be attributed the highest rate of morbidity and mortality in patients with chronic kidney disease (CKD). The aim of our study was to evaluate the prevalence of CKD in patients with symptomatic ischaemic cerebrovascular disease and to establish of whether CKD may define a particular risk pattern of cerebral vessels modifications in this category of patients. The prevalence of CKD was evaluated in 590 consecutive patients with symptomatic ischaemic cerebrovascular disease admitted to a department of neurology. The types of stroke, the vascular territories, the vascular modifications and the haemodynamic changes (resistance index- RI) found by neurosonology (extracranial and transcranial Doppler ultrasound) were analysed in relation to classic and non-classic cerebrovascular risk factors, as well as to stages of CKD (defined by estimated glomerular filtration rate-eGFR-MDRD4 formula-K/DOQI 2002). The prevalence of CKD in the studied patients was 70.84%. Atherosclerosis in a diffuse pattern was detected in 79.7% of CKD patients, while carotid artery stenoses were found in 10% of cases, occlusions- 5.3%, stenoses + occlusions-1.2%, and multiple stenoses- 3.8% of cases. The RI evaluated in the internal carotid arteries correlated with fibrinogen(P<0.0001) and GFR(P<0.0001), while IR in the middle cerebral arteries correlated with fibrinogen(P<0.05), C-reactive protein(P<0.0001), and GFR(P<0.0001). There is a strong relation between symptomatic cerebrovascular disease and CKD, a fact demonstrated by the increased prevalence of CKD in these patients and by the severity of the cerebral vessels lesions.

Ischaemic stroke in incident dialysis patients

BACKGROUND

Despite the high frequency of cardiovascular disease among the population on dialysis, there are few studies on ischaemic stroke and associated factors. The objective of the present study is to assess the prevalence of ischaemic stroke at the start of dialysis, its incidence in the course of follow-up and possible factors associated in its presentation.

METHODS

All patients in our dialysis programme between 1 January 1999 and 31 December 2005 were included in the study and followed up until death, transplant, transfer out of our catchment area, or conclusion of the study on 31 December 2008. Factors analysed were age, gender, smoking habit, diabetes, hypertension, previous ischaemic stroke, ischaemic coronary disease, peripheral vascular disease and atrial fibrillation. Other factors measured in the first month of dialysis were haematocrit, urea, creatinine, lipids, calcium, phosphorus, parathyroid hormone and albumin.

RESULTS

Of 449 patients included in the study (age 64.4 ± 16 years), 30 commenced dialysis having had previous stroke (prevalence 6.7%). In a follow-up of 38.77 ± 29 months, 34 patients presented with one or more strokes; an incidence of 2.41/100 patient-years. Greater age [odds ratio (OR): 1.05; 95% confidence interval (CI): 1.01-1.09; P = 0.007], diabetes (OR: 2.29; 95% CI: 1.15-4.55; P = 0.018) and presence of atrial fibrillation (OR: 3.11; 95% CI: 1.53-6.32; P = 0.002) were independent predictors of stroke occurrence. Conclusions. The prevalence of ischaemic stroke is high at the commencement of dialysis, and its incidence is elevated in the course of follow-up. As with the general population, atrial fibrillation is an important factor predictive of ischaemic stroke, and as such, the clinical implication is that prophylactic anti-coagulation therapy needs to be considered for these individuals.

Role of oxidants/inflammation in declining renal function in chronic kidney disease and normal aging

Oxidant stress (OS) and inflammation increase in normal aging and in chronic kidney disease (CKD), as observed in human and animal studies. In cross-sectional studies of the US population, these changes are associated with a decrease in renal function, which is exhibited by a significant proportion of the population. However, since many normal adults have intact renal function, and longitudinal studies show that some persons maintain normal renal function with age, the link between OS, inflammation, and renal decline is not clear. In aging mice, greater oxidant intake is associated with increased age-related CKD and mortality, which suggests that interventions that reduce OS and inflammation may be beneficial for older individuals. Both OS and inflammation can be readily lowered in normal subjects and patients with CKD stage 3-4 by a simple dietary modification that lowers intake and results in reduced serum and tissue levels of advanced glycation end products. Diabetic patients, including those with microalbuminuria, have a decreased ability to metabolize and excrete oxidants prior to observable changes in serum creatinine. Thus, OS and inflammation may occur in the diabetic kidney at an early time. We review the evidence that oxidants in the diet directly lead to increased serum levels of OS and inflammatory mediators in normal aging and in CKD. We also discuss a simple dietary intervention that helps reduce OS and inflammation, an important and achievable therapeutic goal for patients with CKD and aging individuals with reduced renal function.

A prospective study of albuminuria and cognitive function in older adults: the Rancho Bernardo study

Chronic kidney disease is a risk factor for cognitive impairment. Albuminuria is an early manifestation of chronic kidney disease and a marker of endothelial dysfunction and vascular risk. Results of prior studies of albuminuria and cognitive function are contradictory. The authors studied 1,345 community-dwelling women and men in southern California (mean age, 75 years) at a 1992-1996 research clinic visit, when urine albumin/creatinine ratio (ACR) was measured in spot morning urine and cognitive function was evaluated by using the Mini-Mental State Examination Trail-Making Test B, and category fluency test. An ACR of > or =30 mg/g was found in 17% of women and 15% of men in 1992-1996. Analysis of covariance was used to compare cognitive function score by categorical ACR. Between 1999 and 2002, 759 participants returned for repeat cognitive function testing. For men, but not women, baseline albuminuria, but not estimated glomerular filtration rate, was associated with reduced cognitive function at follow-up on all tests (P's < 0.05). An ACR of > or =30 mg/g was associated with greater annual decline in Mini-Mental State Examination and category fluency scores. Albuminuria may be an easily measured marker predicting future cognitive function decline. Results imply a common underlying mechanism affecting the renal and cerebral microvasculature.

Chronic kidney disease and cognitive function in older adults: findings from the chronic renal insufficiency cohort cognitive study

OBJECTIVES

To investigate cognitive impairment in older, ethnically diverse individuals with a broad range of kidney function, to evaluate a spectrum of cognitive domains, and to determine whether the relationship between chronic kidney disease (CKD) and cognitive function is independent of demographic and clinical factors.

DESIGN

Cross-sectional.

SETTING

Chronic Renal Insufficiency Cohort Study.

PARTICIPANTS

Eight hundred twenty-five adults aged 55 and older with CKD.

MEASUREMENTS

Estimated glomerular filtration rate (eGFR, mL/min per 1.73 m(2)) was estimated using the four-variable Modification of Diet in Renal Disease equation. Cognitive scores on six cognitive tests were compared across eGFR strata using linear regression; multivariable logistic regression was used to examine level of CKD and clinically significant cognitive impairment (score < or =1 standard deviations from the mean).

RESULTS

Mean age of the participants was 64.9, 50.4% were male, and 44.5% were black. After multivariable adjustment, participants with lower eGFR had lower cognitive scores on most cognitive domains (P<.05). In addition, participants with advanced CKD (eGFR<30) were more likely to have clinically significant cognitive impairment on global cognition (adjusted odds ratio (AOR) 2.0, 95% CI=1.1-3.9), naming (AOR=1.9, 95% CI=1.0-3.3), attention (AOR=2.4, 95% CI=1.3-4.5), executive function (AOR=2.5, 95% CI=1.9-4.4), and delayed memory (AOR=1.5, 95% CI=0.9-2.6) but not on category fluency (AOR=1.1, 95% CI=0.6-2.0) than those with mild to moderate CKD (eGFR 45-59).

CONCLUSION

In older adults with CKD, lower level of kidney function was associated with lower cognitive function on most domains. These results suggest that older patients with advanced CKD should be screened for cognitive impairment.

Atrial fibrillation in hemodialysis patients: clinical features and associations with anticoagulant therapy

Using data from the international Dialysis Outcomes and Practice Patterns Study (DOPPS), we determined incidence, prevalence, and outcomes among hemodialysis patients with atrial fibrillation. Cox proportional hazards models, to identify associations with newly diagnosed atrial fibrillation and clinical outcomes, were stratified by country and study phase and adjusted for descriptive characteristics and comorbidities. Of 17,513 randomly sampled patients, 2188 had preexisting atrial fibrillation, with wide variation in prevalence across countries. Advanced age, non-black race, higher facility mean dialysate calcium, prosthetic heart valves, and valvular heart disease were associated with higher risk of new atrial fibrillation. Atrial fibrillation at study enrollment was positively associated with all-cause mortality and stroke. The CHADS2 score identified approximately equal-size groups of hemodialysis patients with atrial fibrillation with low (less than 2) and higher risk (more than 4) for subsequent strokes on a per 100 patient-year basis. Among patients with atrial fibrillation, warfarin use was associated with a significantly higher stroke risk, particularly in those over 75 years of age. Our study shows that atrial fibrillation is common and associated with elevated risk of adverse clinical outcomes, and this risk is even higher among elderly patients prescribed warfarin. The effectiveness and safety of warfarin in hemodialysis patients require additional investigation.

Cerebrovascular disease incidence, characteristics, and outcomes in patients initiating dialysis: the choices for healthy outcomes in caring for ESRD (CHOICE) study

BACKGROUND

Stroke is the third most common cause of cardiovascular disease death in patients on dialysis therapy; however, characteristics of cerebrovascular disease, including clinical subtypes and subsequent consequences, have not been well described.

STUDY DESIGN

Prospective national cohort study, the Choices for Healthy Outcomes in Caring for End-Stage Renal Disease (CHOICE) Study.

SETTINGS & PARTICIPANTS

1,041 incident dialysis patients treated in 81 clinics enrolled from October 1995 to July 1998, followed up until December 31, 2004.

PREDICTOR

Time from dialysis therapy initiation.

OUTCOMES & MEASUREMENTS

Cerebrovascular disease events were defined as nonfatal (hospitalized stroke and carotid endarterectomy) and fatal (stroke death) events after dialysis therapy initiation. Stroke subtypes were classified by using standardized criteria from the Trial of ORG 10172 in Acute Stroke Treatment (TOAST) system. The incidence of cerebrovascular event subtypes was analyzed by using time-to-event analyses accounting for competing risk of death. Clinical outcomes after stroke were abstracted from medical records.

RESULTS

165 participants experienced a cerebrovascular event with an overall incidence of 4.9 events/100 person-years. Ischemic stroke was the most common (76% of all 200 events), with cardioembolism subtype accounting for 28% of the 95 abstracted ischemic events. Median time from onset of symptoms to first stroke evaluation was 8.5 hours (25th and 75th percentiles, 1 and 42), with only 56% of patients successfully escaping death, nursing home, or skilled nursing facility.

LIMITATIONS

Relatively small sample size limits power to determine risk factors.

CONCLUSIONS

Cerebrovascular disease is common in dialysis patients, is identified late, and carries a significant risk of morbidity and mortality. Stroke etiologic subtypes on dialysis therapy are multifactorial, suggesting risk factors may change the longer one has end-stage renal disease. Additional studies are needed to address the poor prognosis through prevention, early identification, and treatment.

Impact of proteinuria and glomerular filtration rate on risk of thromboembolism in atrial fibrillation: the anticoagulation and risk factors in atrial fibrillation (ATRIA) study

BACKGROUND

Atrial fibrillation (AF) substantially increases the risk of ischemic stroke, but this risk varies among individual patients with AF. Existing risk stratification schemes have limited predictive ability. Chronic kidney disease is a major cardiovascular risk factor, but whether it independently increases the risk for ischemic stroke in persons with AF is unknown.

METHODS AND RESULTS

We examined how chronic kidney disease (reduced glomerular filtration rate or proteinuria) affects the risk of thromboembolism off anticoagulation in patients with AF. We estimated glomerular filtration rate using the Modification of Diet in Renal Disease equation and proteinuria from urine dipstick results found in laboratory databases. Patient characteristics, warfarin use, and thromboembolic events were ascertained from clinical databases, with validation of thromboembolism by chart review. During 33,165 person-years off anticoagulation among 10,908 patients with AF, we observed 676 incident thromboembolic events. After adjustment for known risk factors for stroke and other confounders, proteinuria increased the risk of thromboembolism by 54% (relative risk, 1.54; 95% CI, 1.29 to 1.85), and there was a graded, increased risk of stroke associated with a progressively lower level of estimated glomerular filtration rate compared with a rate > or =60 mL x min(-1) x 1.73 m(-2): relative risk of 1.16 (95% CI, 0.95 to 1.40) for estimated glomerular filtration rate of 45 to 59 mL x min(-1) x 1.73 m(-2) and 1.39 (95% CI, 1.13 to 1.71) for estimated glomerular filtration rate <45 mL x min(-1) x 1.73 m(-2) (P=0.0082 for trend).

CONCLUSIONS

Chronic kidney disease increases the risk of thromboembolism in AF independently of other risk factors. Knowing the level of kidney function and the presence of proteinuria may improve risk stratification for decision making about the use of antithrombotic therapy for stroke prevention in AF.

Long-term prognosis of acute kidney injury after first acute stroke

BACKGROUND AND OBJECTIVES

Acute kidney injury (AKI) has been associated with increased mortality in a variety of clinical settings. We studied the incidence, predictors, and effect of AKI on long-term overall mortality and cardiovascular events after stroke.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a prospective outcome study of 2155 patients who sustained an acute first-ever stroke and were followed for 10 yr. Patients were divided in two groups: (1) Those with an acute increase (over 48 h) in serum creatinine >or=0.3 mg/dl or a percentage increase of >or=50% and (2) those with a change <0.3 mg/dl, no change at all, or even a reduction.

RESULTS

Twenty-seven percent of patients developed AKI after acute stroke. Stroke severity, baseline estimated GFR, heart failure, and stroke subtype predict the occurrence of AKI. The probability of 10-yr mortality for patients with AKI was 75.9 and 57.7 in the patients without AKI (log rank test 45.0; P = 0.001). When patients with AKI were subdivided into three groups according to AKI severity, the probability of 10-yr mortality increased: 73.7, 86.5, and 89.2 in stages 1, 2, and 3, respectively. In Cox proportional hazard analysis, AKI was an independent predictor of 10-yr mortality (P < 0.01) and for the occurrence of new composite cardiovascular events (P < 0.05) after adjustment for available confounding variables.

CONCLUSIONS

AKI after stroke is a powerful and independent predictor of 10-yr mortality and new composite cardiovascular events.

Chronic kidney disease and clinical outcome in patients with acute stroke

BACKGROUND AND PURPOSE

Chronic kidney disease (CKD) is increasingly recognized as an independent risk factor for cardiovascular disease and stroke. Our aim was to examine the association between estimated glomerular filtration rate (GFR) and stroke outcome and to assess whether CKD and its severity affect stroke outcome in a large cohort of unselected patients with acute stroke.

METHODS

We examined the association between baseline estimated GFR and CKD and 1-year outcomes in 821 consecutive patients with acute stroke (ischemic or hemorrhagic). GFR was estimated by 2 methods: the Modification of Diet in Renal Disease and the Mayo Clinic quadratic equation. An estimated GFR rate <or=60 mL/min/1.73 m(2) defined CKD.

RESULTS

Odds ratios (95% CI) for death across levels of estimated GFR based on both equations were estimated. CKD was present in 36% (n=291) of patients based on the Modification of Diet in Renal Disease equation and 18% (n=147) based on the Mayo Clinic equation. The adjusted ORs for mortality after 1-year based on the Modification of Diet in Renal Disease equation were 0.7 (95% CI, 0.4 to 1.2) associated with GFR 45 to 60 and 3.2 (1.7 to 6.4) associated with GFR 15 to 44 as compared with GFR >60 mL/min/1.73 m(2), whereas those based on the Mayo Clinic equation were 2.3 (1.1 to 4.7) and 3.3 (1.6 to 7.1), respectively. The adjusted ORs for Barthel Index <or=75 or death after 1 year were 0.8 (0.5 to 1.5) and 2.1 (0.9 to 4.8) by the Modification of Diet in Renal Disease equation and 1.9 (0.8 to 4.4) and 3.9 (1.5 to 11.0) by the Mayo Clinic equation, respectively.

CONCLUSIONS

CKD is a strong independent predictor of mortality and poor outcome in patients with acute stroke. The estimation of the prevalence of CKD and of the GFR cutoffs associated with poor outcome depend on the equation used to estimate GFR.

High prevalence of intracranial artery calcification in stroke patients with CKD: a retrospective study

BACKGROUND AND OBJECTIVES

Intracranial artery calcification (IAC) is frequently observed on brain computed tomography (CT) scans in stroke patients. This retrospective study was designed to determine the prevalence, risk factors, and clinical relevance of IAC in a cohort of patients with ischemic stroke.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We included all eligible patients admitted to Amiens University Hospital for acute ischemic stroke between January and December 2006 and assessed using 64-slice multidetector-row CT (n = 340). Patients were classified according to the presence or absence of IAC in the internal carotid arteries, middle cerebral arteries, vertebral arteries, and basilar artery. GFR was estimated using the MDRD equation. Chronic kidney disease (CKD) was defined as a GFR < 60 ml/min/1.73 m(2). We also studied a control group of patients admitted for neurologic diseases other than stroke.

RESULTS

Two hundred fifty-nine stroke patients (76.2%) displayed IAC, which was independently associated with carotid atherosclerosis > 50%, age, and GFR. One hundred three nonstroke patients (60.2%) had IAC, with age, arterial hypertension, and GFR as independently associated factors. For all patients taken together, age, arterial hypertension, stroke, and GFR were independently associated with IAC.

CONCLUSION

These results confirm the high prevalence of IAC in patients with and without ischemic stroke and show for the first time that IAC is associated with the presence of CKD in these patients. The frequency of IAC was significantly higher in stroke patients than in nonstroke patients. The association between IAC and stroke outcome requires further investigation.

Asymmetric dimethylarginine: a novel marker of risk and a potential target for therapy in chronic kidney disease

PURPOSE OF REVIEW

Asymmetric dimethylarginine (ADMA) is a naturally occurring amino acid that reduces the bioavailability of nitric oxide. ADMA opposes important antiatherosclerotic effects of nitric oxide. ADMA not only correlates with traditional and nontraditional risk factors but is also considered a common pathway mediating the adverse vascular effects of traditional and nontraditional risk factors. Over the past 15 years, ADMA has generated increasing interest from both clinical scientist and basic researchers. The present study summarizes the latest developments in the field.

RECENT FINDINGS

Modulating (increasing) activity of dimethylamine dimethylaminohydrolase, the main enzyme metabolizing ADMA, emerges as a possible therapeutic option to lower ADMA and favorably influence organ dysfunction. These preclinical findings are thought to be of major importance as ADMA predicts cardiovascular events and mortality in the general population and in patients with chronic kidney disease. Also, ADMA uniformly predicts the progression of moderate and severe chronic kidney disease. Symmetrical dimethylarginine, the structural isomer of ADMA, which was mistakenly thought to be without biological relevance, indicates the degree of renal impairment.

SUMMARY

ADMA also beautifully explains many facets of the pathophysiology of chronic kidney disease. Future preclinical and especially clinical studies are required to prove the importance of ADMA in renal and cardiovascular disease.

Lipoprotein (a) as a risk factor for silent cerebral infarction in hemodialysis patients

In patients with chronic renal failure undergoing hemodialysis (HD), silent cerebral infarctions (SCIs) are associated with high mortality. Levels of lipoprotein (a) (Lp[a]) increase with renal dysfunction and may be a novel predictor for cerebrovascular events. We tested the hypothesis that increased Lp(a) levels correlate with the occurrence of SCI in HD patients. Using cranial magnetic resonance imaging findings, we divided 62 Japanese patients undergoing HD into with-SCI group (61 +/- 7 years, mean +/- SD, n = 34) and without-SCI group (60 +/- 6 years, n = 28). We compared the sex, body mass index, metabolic profiles, Lp(a) levels, and smoking habits between the 2 groups. The following observations were noted: (1) The number of patients with diabetes or hypertension did not differ between the 2 groups. (2) The levels of Lp(a) were higher in the with-SCI group in comparison with the without-SCI group (P < .0001). (3) The proportion of smokers was higher in the with-SCI group than in the without-SCI group (P < .05). (4) Plasma levels of high-density lipoprotein cholesterol were lower, whereas uric acid was higher, in the with-SCI group than in the without-SCI group (P < .001 and P < .05, respectively). (5) Multiple logistic regression analysis identified Lp(a) levels as being significantly associated with the presence of SCI (odds ratio, 1.23; 95% confidence interval, 1.09-1.38; P < .0001). This study indicates that patients with chronic renal failure, who are maintained on HD, exhibit an increased prevalence of SCI and that Lp(a) is significantly associated with the presence of SCI in HD patients.

Outcomes of carotid revascularization in patients with chronic kidney disease

Chronic kidney disease (CKD) carries an increased risk for cardiovascular disease (CVD) including cerebrovascular accidents (CVAs). There are multiple etiologies for CVA, and among them extracranial carotid artery disease accounts for approximately 25% of ischemic strokes. It has been shown that carotid revascularization by carotid endarterectomy and carotid artery angioplasty and stenting can decrease the risk of CVA in appropriately selected population with carotid artery disease. Both these techniques of carotid revascularization have been shown to be safe and clinically effective in many large multicentered randomized clinical trials. However, most of these large trials have predominately excluded the patients with kidney failure. Most of the evidence for the management of carotid disease in CKD is based on small clinical trials and expert opinions. There is an urgent need to conduct large clinical trials in patients with CKD to enable better understanding and to improve techniques of various carotid revascularization therapies in CKD patients.

New insights into stroke in chronic kidney disease

Patients with chronic kidney disease (CKD) are predisposed to stroke, especially as the estimated glomerular filtration rate decreases. This update reviews the pathologic mechanisms particular to this stroke population. The treatment for primary and secondary prevention of stroke is reviewed with respect to antiplatelet agents, anticoagulants, surgery, and carotid stenting. The control of chronic hypertension is particularly important in reducing stroke risk in CKD. In patients with prior stroke from atherosclerosis, antiplatelet agents are most beneficial in reducing secondary stroke risk. Those with atrial fibrillation and CKD may benefit from warfarin anticoagulation. Statins in CKD for stroke reduction in diabetics receiving dialysis are not useful, and the data are pending for their use in stroke reduction in the general CKD population. In carefully selected cases, carotid endarterectomy can be a treatment. The data on carotid stenting are conflicting.

Kidney function and cognitive performance and decline in older men

OBJECTIVES

To examine the association between kidney function and cognitive impairment and decline in elderly men.

DESIGN

Observational prospective cohort.

SETTING

Community based.

PARTICIPANTS

Five thousand five hundred twenty-nine community dwelling men aged 65 and older (mean age 73.6 +/- 5.9).

MEASUREMENTS

Estimated glomerular filtration rate (eGFR) calculated using the standardized Modification of Diet in Renal Disease (MDRD) equation; cognitive function assessed using the Modified Mini-Mental State Examination (3MS) and Trail Making Test B (Trails B).

RESULTS

At baseline, 148 (2.7%) and 494 (9.1%) men were classified as cognitively impaired and, in the 5-year prospective analysis, 931 (23%) and 432 (11.6%) met the criteria for cognitive decline at follow-up defined according to 3MS and Trails B performance, respectively. In unadjusted analysis, the odds of prevalent cognitive impairment and risk of cognitive decline were significantly higher in men with an eGFR less than 45 and 45 to 59 mL/min per 1.73 m(2) than in men with an eGFR 60 mL/min per 1.73 m(2) or greater. Differences in age, race, and education between eGFR categories largely explained these associations, with the exception of the association between poorer renal function and higher odds of impairment based on Trails B test score, which persisted despite adjustment for multiple potential confounders.

CONCLUSION

This study found evidence of an independent association between mild to moderate reductions in kidney function and poor executive function at baseline but not with global cognitive impairment or risk of cognitive decline in older men.

Cognitive function in chronic kidney disease

Chronic kidney disease (CKD) is a growing public health problem. The incidence of kidney failure is rising in all age groups but particularly in older adults. Individuals in all stages of CKD are at higher risk for development of cognitive impairment and this may be a major determinant in their quality of life. Furthermore, cognitive impairment is associated with an increased risk of death in dialysis patients. Cerebrovascular disease is a strong risk factor for development of cognitive impairment and vascular disease is a more likely cause of cognitive impairment than Alzheimer's disease in patients with CKD. Both traditional and nontraditional vascular risk factors are more common in CKD and dialysis patients may also be at risk for cognitive impairment via nonvascular risk factors and the hemodialysis procedure itself. Unfortunately, because risk factors for cognitive impairment in CKD have not been thoroughly ascertained, evaluation of potential treatments has been limited. Given the high prevalence of cognitive impairment in all stages of CKD, additional studies are needed to evaluate potential risk factors and treatments in this vulnerable population.

Stroke in chronic renal failure

Chronic kidney diseases and cardiovascular diseases have several common risk factors like hypertension and diabetes. In chronic renal disease stroke risk is several times higher than in the average population. The combination of classical risk factors and those characteristic of chronic kidney disease might explain this increased risk. Among acute cerebrovascular diseases intracerebral hemorrhages are more frequent than in those with normal kidney function. The outcome of stroke is worse in chronic kidney disease. The treatment of stroke (thrombolysis, antiplatelet and anticoagulant treatment, statins, etc.) is an area of clinical research in this patient group. There are no reliable data on the application of thrombolysis in acute stroke in patients with chronic renal disease. Aspirin might be administered. Carefulness, individual considerations and lower doses might be appropriate when using other treatments. The condition of the kidney as well as other associated diseases should be considered during administration of antihypertensive and lipid lowering medications.

Cognitive impairment in the aging dialysis and chronic kidney disease populations: an occult burden

The high burden of cognitive impairment in hemodialysis and chronic kidney disease (CKD) patients has only recently become recognized. Up to 70% of hemodialysis patients aged 55 years and older have moderate to severe chronic cognitive impairment, yet it is largely undiagnosed. Recent studies describe the strong graded relation between estimated glomerular filtration rate and cognitive function in CKD patients. The process of conventional hemodialysis may induce recurrent episodes of acute cerebral ischemia, which, in turn, may contribute to acute decline in cognitive function during dialysis. Thus, the worst time to communicate with dialysis patients may be during the hemodialysis session. Both symptomatic and occult, subclinical ischemic cerebrovascular disease appears to play a large role in a proposed model of accelerated vascular cognitive impairment in these populations. Severe cognitive impairment or dementia among hemodialysis patients is associated with an approximately 2-fold increased risk of both mortality and dialysis withdrawal. Predialysis cognitive screening and adding dementia to the list of comorbidities on Form 2728 would provide critical information regarding the benefit versus risks of receiving dialysis. It could also improve quality of care and outcomes by raising clinicians' awareness of the potential effects of cognitive impairment on medication, fluid, and dietary compliance and the ability to make advance directive decisions among dialysis patients. Although much remains to be learned regarding the pathophysiology of cognitive impairment in kidney disease, the public health implications of this substantial burden are immediate.

High-sensitivity C-reactive protein level is a significant risk factor for silent cerebral infarction in patients on hemodialysis

In patients with chronic renal failure on hemodialysis (HD), silent cerebral infarctions (SCIs) are associated with high mortality. The levels of high-sensitivity C-reactive protein (HSCRP), a marker of inflammation and atherosclerosis, elevate with increasing renal dysfunction. We tested the hypothesis that increased HSCRP levels correlate with the occurrence of SCI in HD patients. By brain magnetic resonance imaging findings, we divided 54 patients undergoing HD into a with-SCI group (61 +/- 8 years, n = 30) and a without-SCI group (60 +/- 7 years, n = 24). We compared sex, body mass index, metabolic profiles, HSCRP levels, and smoking habits in Japanese patients on HD with and without SCI. We made the following observations: (1) The number of patients with diabetes or hypertension did not differ between the 2 groups. (2) The levels of HSCRP were higher in the with-SCI group in comparison with the without-SCI group (P < .0001). (3) The proportion of smokers was higher in the with-SCI group than in the without-SCI group (P < .05). (4) Plasma levels of high-density lipoprotein cholesterol were lower, whereas uric acid was higher, in the with-SCI group than in the without-SCI group (P < .05 and P < .0001, respectively). (5) Multivariate logistic analysis identified HSCRP levels as being significantly associated with the presence of SCI (odds ratio, 1.61; 95% confidence interval, 1.17-2.85; P < .001). This study indicates that patients in chronic renal failure who are maintained on HD exhibit an increased prevalence of SCI and that HSCRP is significantly associated with the presence of SCI in HD patients.

Kidney function is related to cerebral small vessel disease

BACKGROUND AND PURPOSE

Poor kidney function, as measured by glomerular filtration rate (GFR), is closely associated with presence of glomerular small vessel disease. Given the hemodynamic similarities between the vascular beds of the kidney and the brain, we hypothesized an association between kidney function and markers of cerebral small vessel disease on MRI. We investigated this association in a population-based study of elderly persons.

METHODS

We measured GFR using the Cockcroft-Gault equation in 484 participants (60 to 90 years of age) from the Rotterdam Scan Study. Using automated MRI-analysis we measured global as well as lobar and deep volumes of gray matter and white matter, and volume of WML. Lacunar infarcts were rated visually. Volumes of deep white matter and WML and presence of lacunar infarcts reflected cerebral small vessel disease. We used linear and logistic regression models to investigate the association between GFR and brain imaging parameters. Analyses were adjusted for age, sex, and additionally for cardiovascular risk factors.

RESULTS

Persons with lower GFR had less deep white matter volume (difference in standardized volume per SD decrease in GFR: -0.15 [95% CI -0.26 to -0.04]), more WML (difference per SD decrease in GFR: 0.14 [95% CI 0.03 to 0.25]), and more often lacunar infarcts, although the latter was not significant. GFR was not associated with gray matter volume or lobar white matter volume. Additional adjustment for cardiovascular risk factors yielded similar results.

CONCLUSIONS

Impaired kidney function is associated with markers of cerebral small vessel disease as assessed on MRI.

Stroke and its prevention in chronic kidney disease

This is a review of stroke mechanisms and management. The concept of stroke and transient ischemic attack and the recently proposed revision in definitions and controversies are discussed. We also discuss the use of antiplatelet and anticoagulant drugs for stroke due to carotid and cardiac disease.

Chronic kidney disease, cardiovascular events, and the effects of perindopril-based blood pressure lowering: data from the PROGRESS study

Chronic kidney disease (CKD) is associated with a high risk of cardiovascular disease, but evidence regarding the effectiveness of interventions to reduce that risk is lacking. The Perindopril Protection against Recurrent Stroke Study (PROGRESS) study enrolled 6105 participants with cerebrovascular disease and randomly allocated them to perindopril-based blood pressure-lowering therapy or placebo. Individuals with CKD were at approximately 1.5-fold greater risk of major vascular events, stroke, and coronary heart disease, and were more than twice as likely to die (all P< or =0.002). Perindopril-based treatment reduced the risk of major vascular events by 30% and stroke by 35% among subjects with CKD, and the absolute effects of treatment were 1.7-fold greater for those with CKD than for those without. Considering patients with CKD and a history of cerebrovascular disease, perindopril prevented one stroke or other cardiovascular event among every 11 patients treated over five years. In conclusion, kidney function should be considered when determining the need for blood pressure lowering therapy in patients with cerebrovascular disease.