Anemia and left ventricular hypertrophy in chronic kidney disease populations: a review of the current state of knowledge

The increasing awareness of the high prevalence of cardiovascular disease (CVD) in the dialysis population has led clinical nephrologists and researchers to focus their attention on processes and factors that are present in patients prior to dialysis. It is clear that many of the risk factors for kidney disease and cardiovascular disease are similar: This may account for the high prevalence of CVD within the dialysis population. However, it is evident that there are unique risk factors for CVD that are present in patients with chronic kidney disease (CKD). These unique uremia-related risk factors for CVD include anemia, hyperparathyroidism, abnormalities of mineral metabolism, and acidosis. Of note, the association of anemia, or lower levels of hemoglobin, have been consistently described in all populations with kidney disease. Left ventricular hypertrophy has long been known as an independent risk factor for death and CV events, in both the dialysis and general populations. There have been accumulating data that LVH and left ventricular (LV) growth occur prior to dialysis in patients with kidney disease, and that the prevalence of LVH in that group of patients is caused by, conventional risk factors for LVH (e.g., hypertension) as well as nonconventional risk factors such as anemia.     

Cardiovascular disease in patients with chronic kidney disease

Cardiovascular disease (CVD) is the major cause of morbidity and mortality in patients with renal failure. Patients with chronic kidney disease have significant CVD, and carry a high cardiovascular burden by the time they commence renal replacement therapy (RRT). The severity of CVD that has been observed in dialysis patients lead to a growing body of research examining the pathogenesis and progression of CVD during the progression of chronic kidney disease (CKD) to end-stage renal disease (ESRD) (ie, predialysis phase). Multiple factors are involved in the development of CVD in CKD. More importantly, critical and key factors seem to develop early in the course of CKD, and result in preventable worsening of CVD in this patient population. Anemia is common in patients with CKD, and has been shown to have an independent role in the genesis of left ventricular hypertrophy (LVH) and subsequent CVD. Unfortunately, it is underdiagnosed and undertreated in patients with CKD. Early intervention, and better correction of anemia, seems to gain a great momentum in the prevention and management of CVD in CKD. Hypertension is another risk factor that has been targeted by the National Kidney Foundation Task Force on CVD in chronic kidney disease. This article reviews the different factors involved in the pathogenesis of CVD in CKD and the evidence supporting early and aggressive intervention.     

Cardiovascular disease in children with chronic kidney disease

In children with end-stage renal disease (ESRD), cardiovascular disease (CVD) mortality has not changed for the past 3 decades. Cardiac disease remains the second most common cause of death. Recent data demonstrate a high incidence and prevalence of traditional and chronic kidney disease (CKD)-related CVD risk factors in children. Early markers of cardiomyopathy, such as left ventricular hypertrophy (LVH) and left ventricular dysfunction (LV dysfunction), and early markers of atherosclerosis, such as increased carotid artery intima-media thickness (IMT) and carotid arterial wall stiffness, are frequently found in this patient population. Early identification of modifiable risk factors and treatment of asymptomatic CVD might lead to decrease of cardiovascular morbidity and mortality in young adults who developed CKD during childhood.     

Cardiovascular care in end-stage renal disease

Cardiovascular disease (CVD) accounts for the majority of morbidity and mortality in patients with end-stage renal disease (ESRD). Chronic kidney disease, and ESRD as its most severe form, are now acknowledged to be independent risk factors for CVD. The spectrum of CVD includes accelerated atherosclerosis, myocardial disease and heart failure, cardiac arrhythmias, and valvular heart disease. In addition, CKD and ESRD are independent and powerful factors that complicate cardiovascular procedures and have been directly linked to increased mortality. This issue of Advances in Chronic Kidney Disease will explore the spectrum of risk and the opportunities to improve care in ESRD in outpatient management, during dialysis, after kidney transplantation, and in coronary revascularization.     

Left ventricular hypertrophy in predialysis chronic kidney disease: impact of cardiomuscular stress markers

Left ventricular hypertrophy (LVH), which is a strong predictor of mortality in patients with endstage renal disease, is present in over 70% of patients commencing dialysis. However, only a few studies on LVH are available in patients before the start of dialysis treatment. The purpose of this study was to evaluate the prevalence and clinical correlates of LVH in patients with advanced stages of chronic kidney disease(CKD). We performed a cross sectional study of 90 patients who had renal diseases but no history of either cardiovascular diseases or arrhythmia. Circulating levels of human atrial natriuretic peptide (hANP) were also measured. LVH was present in 40.0% of the study population. The prevalence of LVH tended to increase with progression of renal decline: 22.7% in stage 3, 43.6% in stage 4, and 48.3% in stage 5 (creatinine clearance >10 mL/min) (p = 0.15). Univariate analyses revealed that hANP and albumin were significantly different between the groups with and without LVH. Stepwise logistic regression analysis showed that hANP and albumin were selected as the independent risk factors. These findings suggest that strict control of body fluid and nutrition could prevent the progression of LVH, and as a result, could attenuate the risk of cardiovascular events in CKD.     

The epidemics of cardiovascular disease in elderly patients with chronic kidney disease – Two facets of the same problem

There is increasing evidence that even mild renal dysfunction is a novel potent cardiovascular risk factor in the general elderly population. With more severe renal impairment, cardiovascular risk increases proportionately. This issue deserves attention, as chronic kidney disease (CKD) is predominantly a disease of the elderly, and the mean age of end-stage renal disease patients entering dialysis is growing constantly. In the dialysis population, when clinically significant cardiovascular disease (CVD) (particularly congestive heart failure) is present, survival is worse. Thus, every effort should be made to identify and treat cardiovascular risk factor in the early stages of CKD. However, elderly renal patients receive less proper cardiovascular therapy compared to non-renal subjects of the same age. This review deals briefly with the most significant data published in the last decade on CVD in elderly with CKD.     

Glucose intolerance: is it a risk factor for cardiovascular disease in children with chronic kidney disease?

A total of 66 children and adolescents with chronic kidney disease (CKD) (20 pre-dialysis patients and 46 chronic dialysis patients) were evaluated to address the prevalence of abnormalities in glucose and insulin metabolism and their association with cardiovascular disease. Glucose intolerance was assessed using an oral glucose tolerance test; insulin resistance was estimated by the homeostasis model assessment of insulin resistance (HOMA-IR). Carotid artery intima-media thickness (IMT) and left ventricular hypertrophy (LVH) were examined as early markers of cardiovascular disease. Thirty-four patients (7 pre-dialysis, 27 dialysis) exhibited an abnormal glucose tolerance; however, ten patients (7 pre-dialysis, 3 dialysis) were insulin-resistant. Height-specific standard deviation scores of carotid artery IMT were above normal in three of the pre-dialysis patients (15%) and in 34 of the dialysis patients (74%). LVH was present in seven pre-dialysis (35%) and 34 dialysis patients (74%). In addition, two of the pre-dialysis patients (10%) and 18 of the dialysis patients (39%) had severe LVH. The prevalence of both increased carotid artery IMT and LVH were similar in patients with or without glucose intolerance in both groups, but severe LVH was more prevalent in pre-dialysis patients with glucose intolerance (p = 0.042). The multivariate analyses showed that neither carotid artery IMT nor LVM index was predicted by serum glucose levels or HOMA-IR. In conclusion, children with CKD are at a high risk of glucose intolerance and also have a greater risk of subclinical cardiovascular disease (CVD). However, the presence of glucose intolerance does not appear to be an independent risk factor for increased carotid artery IMT or LVH.     

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.     

Phosphate in early chronic kidney disease: associations with clinical outcomes and a target to reduce cardiovascular risk

There is an intimate association between mineral and bone disorders in chronic kidney disease (CKD) and the extensive burden of cardiovascular disease (CVD) in this population. High phosphate levels in CKD have been associated with increased all-cause mortality and cardiovascular morbidity and mortality. Observational studies have also shown a consistent relationship between serum phosphate in the normal range and all-cause and cardiovascular mortality, left ventricular hypertrophy (LVH) and decline in renal function. Furthermore, fibroblast growth factor-23 (FGF-23), a phosphaturic hormone, increases very early in the course of CKD and is strongly associated with death and CVD, including LVH and vascular calcification. Few studies have addressed outcomes using interventions to reduce serum phosphate in a randomized controlled fashion; however, strategies to address cardiovascular risk in early CKD are imperative and phosphate is a potential therapeutic target. This review outlines the epidemiological and experimental evidence highlighting the relationship between excess phosphate and adverse outcomes, and discusses clinical studies required to address this problem.     

Cardiovascular disease in children with chronic kidney disease

More than a decade ago, cardiovascular disease (CVD) was recognized as a major cause of death in children with advanced CKD. This observation has sparked the publication of multiple studies assessing cardiovascular risk, mechanisms of disease, and early markers of CVD in this population. Similar to adults, children with CKD have an extremely high prevalence of traditional and uremia-related CVD risk factors. Early markers of cardiomyopathy, such as left ventricular hypertrophy and dysfunction, and early markers of atherosclerosis, such as increased carotid artery intima-media thickness, carotid arterial wall stiffness, and coronary artery calcification, are frequently present in these children, especially those on maintenance dialysis. As a population without preexisting symptomatic cardiac disease, children with CKD potentially receive significant benefit from aggressive attempts to prevent and treat CVD. Early CKD, before needing dialysis, is the optimal time to both identify modifiable risk factors and intervene in an effort to avert future CVD. Slowing the progression of CKD, avoiding long-term dialysis and, if possible, conducting preemptive transplantation may represent the best strategies to decrease the risk of premature cardiac disease and death in children with CKD.     

Chronic kidney disease and cardiovascular disease in the Medicare population

BACKGROUND: The extent of diabetes, chronic kidney disease (CKD), and cardiovascular disease (CVD) in the Medicare population is relatively unknown. Also unknown is the effect of these diseases on patient survival before end-stage renal disease (ESRD). METHODS: Prevalent cohorts of Medicare enrollees from 1996 to 2000 were assessed for diabetes and CKD, presence of CVD, and probability of death versus ESRD in the follow-up period. Hospitalization rates and, in diabetics, lipid testing and glycemic control monitoring were also assessed. RESULTS: The prevalence of diabetes in the Medicare population increased at 4.4% per year, reaching 18.9% in the 1999-2000 cohort. Approximately 726,000 elderly Medicare enrollees carry a diagnosis code for CKD. Those with CKD are 5 to 10 times more likely to die before reaching ESRD than the non-CKD group. In CKD patients, CVD is twice as common and advances at twice the rate. Cardiovascular disease advances at a similarly higher rate in CKD patients who die and those who survive to ESRD. Heart failure hospitalizations are 5 times greater in CKD patients and only 30% less than those in dialysis patients. Only half of the CKD patients with diabetes who advance to ESRD had a lipid or glycosylated hemoglobin test done in the year before or after dialysis initiation. CONCLUSION: Diabetes, the leading cause of ESRD, is increasing in the general Medicare population at 4.4% per year. Cardiovascular disease is common, progresses at twice the rate, is associated with death before ESRD, and patients receive suboptimal risk factor monitoring. Active identification and treatment of CKD patients is needed.     

Gene polymorphism association studies in dialysis: cardiovascular disease

Cardiovascular disease (CVD) is the most important cause of morbidity and mortality in dialysis patients. The high prevalence of CVD is due to the cumulative effects of multiple risk factors from the early stages of chronic kidney disease (CKD). Familial predispositions to CVD, CKD, and their respective risk factors are well known, and it is likely that genetic factors determine the interindividual variability in risks for disease. Advances in genomic technology have facilitated the study of genetic variation--most commonly single nucleotide polymorphisms (SNPs) in candidate genes--and their associations with disease. This review examines CVD in dialysis patients as a model of a complex disease, discusses the approach to gene polymorphism association studies, including the roles of gene-environment and gene-gene interactions and provides an overview of available studies.     

Traditional cardiac risk factors in individuals with chronic kidney disease

Individuals with chronic kidney disease (CKD) are at increased risk for the development and progression of cardiovascular disease (CVD). The increased risk is due to a higher prevalence of both traditional risk factors as well as nontraditional risk factors. In this review we focus on individuals at all stages of CKD and discuss modifiable traditional risk factors, namely hypertension, dyslipidemia, diabetes mellitus and poor glycemic control, smoking, and physical inactivity. The prevalence of each risk factor and its relationship with CVD is described. Treatment recommendations are provided using evidence available from populations with CKD or evidence extrapolated from the general population when there are insufficient data on individuals with CKD.     

Anemia and the heart in chronic kidney disease

Cardiovascular disease is highly prevalent at all stages of chronic kidney disease (CKD) and is the leading cause of morbidity and mortality. Individuals with CKD commonly have multiple risk factors for the development of cardiovascular disease, including both traditional and nontraditional risk factors. Anemia is a nontraditional cardiovascular risk factor found in CKD that contributes to the development and progression of structural abnormalities of the heart, namely left ventricular hypertrophy and dilation. In addition, a deficiency of erythropoietin per se also may have important pathophysiologic consequences. In this review we summarize the evidence from observational studies showing an association between anemia and adverse cardiac outcomes at all stages of CKD. In addition, we provide an overview of the evidence accumulating from randomized controlled trials conducted in both nondialysis and dialysis CKD populations evaluating the effect of anemia correction on cardiac outcomes such as changes in left ventricular hypertrophy.     

Clinical assessment and management of dyslipidemia in patients with chronic kidney disease

Chronic kidney disease (CKD) is a common cause of cardiovascular disease (CVD). Several factors contribute to the onset and progression of atherosclerosis and CVD in CKD patients. Most of the cases of coronary heart disease in the general population can be explained by traditional risk factors, whereas non-traditional risk factors, including oxidative stress, anemia, inflammation, malnutrition, vascular calcification, and endothelial dysfunction, have been proposed to play a central role in the pathogenesis of CVD in CKD patients. However, the precise mechanism of CVD initiation in CKD patients remains unclear. Lipid-lowering therapies may decrease proteinuria, and increase or maintain renal function. Because the serum levels of triglyceride-rich lipoproteins are increased in CKD patients, particularly in advanced stages, the serum non-HDL cholesterol level may be a better biomarker of dyslipidemia than the serum LDL cholesterol level in this population. A meta-analysis showed that statin therapy was associated with decreased albuminuria in comparison with a placebo. Moreover, lipid-lowering therapy with statins is effective in reducing the risk of CVD in the early stages of CKD, whereas the benefit of statins in patients with end-stage renal disease may be limited.     

慢性肾脏病患者心血管疾病危险因素探讨

目的探讨慢性肾脏病（CKD）患者心血管疾病的危险因素。方法收集我院542例住院CKD患者的病史、实验室检查和辅助检查结果,将患者根据有无心血管疾病分为2组,根据Logistic回归分析结果探讨心血管疾病的危险因素。结果高龄、高血压、高尿酸血症、贫血、蛋白尿是CKD患者心血管疾病的危险因素;CKD1～5期患者心血管疾病的危险因素各不相同。结论CKD进展和CKD患者心血管疾病的发生拥有部分相同的危险因素;在CKD早期以传统危险因素为主,随着肾功能的恶化,非传统危险因素起主导的作用。     

Cardiovascular disease in chronic renal failure: pathophysiologic aspects

Cardiovascular complications are the leading cause of mortality in patients with end-stage renal disease (ESRD). The excess cardiovascular risk and mortality is already demonstrable in early renal disease and in patients with chronic renal failure (CRF), with the highest relative risk of mortality in the youngest patients. The high risk for cardiovascular disease (CVD) results from the additive effect of multiple factors, including hemodynamic overload and several metabolic and endocrine abnormalities more or less specific to uremia. CVD includes disorders of the heart (left ventricular hypertrophy [LVH], cardiomyopathy) and disorders of the vascular system (atherosclerosis, arteriosclerosis), these two disorders being usually associated and interrelated. LVH is the most frequent cardiac alteration in ESRD, resulting from a combined pressure and volume overload. LVH in general is an ominous prognostic sign and an independent risk factor for arrhythmias, sudden death, heart failure, and myocardial ischemia. Regression of LVH needs a combined intervention to reduce hemodynamic overload and is associated with improved prognosis and survival. Clinical studies have shown that damage of large conduit arteries is a major contributing factor for the high incidence of congestive heart failure (CHF), LVH, ischemic heart disease (IHD), sudden death, cerebrovascular accidents, and peripheral artery diseases. Damage to large conduit arteries is principally related to highly calcified occlusive atherosclerotic lesions and to stiffening of large capacitive arteries. These two complications are independent risk factors for survival, and improvement of arterial stiffness is associated with better prognosis and survival. The present review summarizes the most recent works dealing with the pathophysiology of CVD and some aspects of the therapeutic approach.     

Effects of anemia and left ventricular hypertrophy on cardiovascular disease in patients with chronic kidney disease

Left ventricular hypertrophy (LVH) and anemia are highly prevalent in moderate chronic kidney disease (CKD). Because anemia may potentiate the adverse effects of LVH on cardiovascular outcomes, the effect of both anemia and LVH on outcomes in CKD was examined. Data from four community-based longitudinal studies were pooled: Atherosclerosis Risk in Communities Study, Cardiovascular Health Study, Framingham Heart Study, and Framingham Offspring Study. Serum creatinine levels were calibrated indirectly across studies, and GFR was estimated using the Modification of Diet in Renal Disease equation. CKD was defined as GFR between 15 and 60 ml/min per 1.73 m(2). LVH was based on electrocardiogram criteria. Anemia was defined as hematocrit <36% in women and 39% in men. The primary outcome was a composite of myocardial infarction, stroke, and death; a secondary cardiac outcome included only myocardial infarction and fatal coronary heart disease. Among 2423 patients with CKD, 96% had electrocardiogram and anemia data. Median follow-up was 102 mo. In adjusted analysis, LVH was associated with increased risk for composite and cardiac outcomes (hazard ratio [HR], 1.67 [95% confidence interval (CI), 1.34 to 2.07] and 1.62 [95% CI, 1.18 to 2.24], respectively), whereas anemia was associated with increased risk for the only composite outcome (HR, 1.51 [95% CI, 1.27 to 1.81]). The combination of anemia and LVH was associated with an increased risk for both study outcomes compared with individuals with neither risk factor (HR, 4.15 [95% CI, 2.62 to 6.56] and 3.92 [95% CI, 2.05 to 7.48]; P = 0.02 and 0.01 for interaction term, respectively). The combination of anemia and LVH in CKD identifies a high-risk population.     

Novel insight into perirenal adipose tissue: A neglected adipose depot linking cardiovascular and chronic kidney disease

Obesity is associated with adverse metabolic diseases including cardiovascular disease (CVD) and chronic kidney disease (CKD). These obesity-related diseases are highly associated with excess fat accumulation in adipose tissue. However, emerging evidence indicates that visceral adiposity associates more with metabolic and cardiovascular risk factors. Perirenal adipose tissue, surrounding the kidney, is originally thought to provides only mechanical support for kidney. However, more studies demonstrated perirenal adipose tissue have a closer association with renal disease than other visceral fat deposits in obesity. Additionally, perirenal adipose tissue is also an independent risk factor for CKD and even associated more with CVD. Thus, perirenal adipose tissue may be a connection of CVD with CKD. Here, we will provide an overview of the perirenal adipose tissue, a neglected visceral adipose tissue, and the roles of perirenal adipose tissue linking with CVD and CKD and highlight the perirenal adipose tissue as a potential strategy for future therapeutics against obesity-related disease.     

Cardiovascular disease in early stages of chronic kidney disease in a Chinese population

Cardiovascular disease (CVD) is one of the most serious complications of kidney disease, yet studies of CVD in early stage of chronic kidney disease (CKD) in Asian patients are very limited. Therefore, this study determined the prevalence and the spectrum of CVD in individuals with early-stage CKD and compared them with data of individuals without CKD. Compared with individuals with estimated GFR (eGFR) >90 ml/min per 1.73 m2, the prevalence of myocardial infarction, stroke, and total CVD of individuals with eGFR 60 to 89 ml/min per 1.73 m2 was increased by 91.4, 71.7, and 67.6%, respectively. For individuals with eGFR 30 to 59 ml/min per 1.73 m2, the percentage was 105.2, 289.1, and 200.7%, respectively. For each eGFR category, stroke was more prevalent than myocardial infarction. Compared with individuals with eGFR >90 ml/min per 1.73 m2, participants with eGFR 60 to 89 and 30 to 59 ml/min per 1.73 m2 tended to have more cardiovascular risk factors, and there were strong unadjusted and adjusted associations between CVD with different stages of eGFR (eGFR >90 ml/min per 1.73 m2 as reference). This is the first report on the prevalence and the spectrum of CVD in early stages of CKD in a community-based Chinese population. The spectrum of CVD in this Chinese population is different from reports of Western countries. Individuals with subtle decreased renal function seem much more likely to have multiple cardiovascular risk factors and have higher prevalence of CVD than those without CKD.