The clinical epidemiology of cardiovascular disease in chronic kidney disease

Mechanisms of plasminogen activator inhibitor 1 action in stromal remodeling and related diseases

Plasminogen activator inhibitor type 1 (PAI-1) is the main physiologic inhibitor of fibrinolysis. However, it is also involved in many physiological processes such as extracellular matrix (ECM) proteolysis and remodeling, cell adhesion, motility, and apoptosis, angiogenesis, etc. The aim of the study was to summarize current knowledge and gain insights into the mechanisms of PAI-1 action in the processes of stromal remodeling and diseases with considerable matrix pathologies (atherosclerosis, tissue fibrosis, cancer metastasis, pregnancy related complications, etc). As a component of an early cellular response to injury, PAI-1 reacts with membrane surface proteins and participates in the initiation of intracellular signaling, specifically cytoskeletal reorganization and motility. Complexity of ECM homeostasis resides in varying relation of the plasminogen system components and other matrix constituents. Inflammatory mediators (transforming growth factor-β and interferon-γ) and hormones (angiotensin II) are in the close interdependent relation with PAI-1. Also, special attention is devoted to the role of increased PAI-1 concentrations due to the common 4G/5G polymorphism. Some of the novel mechanisms of ECM modification consider PAI-1 dependent stabilization of urokinase mediated cell adhesion, control of the vascular endothelial cadherin trafficking and interaction with endothelial cells proteasome, its relation to matrix metalloproteinase 2 and osteopontin, and oxidative inhibition by myeloperoxidase. Targeting and/or alteration of PAI-1 functions might bring benefit to the future therapeutic approaches in diseases where ECM undergoes substantial remodeling.

Quality of care in patients with diabetic kidney disease in Asia: The Joint Asia Diabetes Evaluation (JADE) Registry

AIMS

Diabetic kidney disease independently predicts cardiovascular disease and premature death. We examined the burden of chronic kidney disease (CKD, defined as an estimated GFR < 60 ml/min/1.73 m(2) ) and quality of care in a cross-sectional survey of adults (age ≥ 18 years) with Type 2 diabetes across Asia.

METHODS

The Joint Asia Diabetes Evaluation programme is a disease-management programme implemented using an electronic portal that systematically captures clinical characteristics of all patients enrolled. Between July 2007 and December 2012, data on 28 110 consecutively enrolled patients (China: 3415, Hong Kong: 15 196, India: 3714, Korea: 1651, Philippines: 3364, Vietnam: 692, Taiwan: 78) were analysed.

RESULTS

In this survey, 15.9% of patients had CKD, 25.0% had microalbuminuria and 12.5% had macroalbuminuria. Patients with CKD were less likely to achieve HbA1c < 53 mmol/mol (7.0%) (36.0% vs. 42.3%) and blood pressure < 130/80 mmHg (20.8% vs. 35.3%), and were more likely to have retinopathy (26.2% vs. 8.7%), sensory neuropathy (29.0% vs. 7.7%), cardiovascular disease (26.6% vs. 8.7%) and self-reported hypoglycaemia (18.9% vs. 8.2%). Despite high frequencies of albuminuria (74.8%) and dyslipidaemia (93.0%) among CKD patients, only 49.0% were using renin-angiotensin system inhibitors and 53.6% were on statins. On logistic regression, old age, male gender, tobacco use, long disease duration, high HbA1c , blood pressure and BMI, and low LDL cholesterol were independently associated with CKD (all P < 0.05).

CONCLUSIONS

The poor control of risk factors, suboptimal use of organ-protective drugs and high frequencies of hypoglycaemia highlight major treatment gaps in patients with diabetic kidney disease in Asia.

Increased risk of atrial fibrillation in end-stage renal disease patients on dialysis: A nationwide, population-based study in Taiwan

End-stage renal disease (ESRD) patients commonly have a higher risk of developing cardiovascular diseases than general population. Chronic kidney disease is an independent risk factor for atrial fibrillation (AF); however, little is known about the AF risk among ESRD patients with various modalities of renal replacement therapy. We used the Taiwan National Health Insurance Research Database to determine the incident AF among peritoneal dialysis (PD) and hemodialysis (HD) patients in Taiwan.Our ESRD cohort include Taiwan National Health Insurance Research Database, we identified 15,947 patients, who started renal replacement therapy between January 1, 2002 and December 31, 2003. From the same data source, 47,841 controls without ESRD (3 subjects for each patient) were identified randomly and frequency matched by gender, age (±1 year), and the year of the study patient's index date for ESRD between January 1, 2002 and December 31, 2003.During the follow-up period (mean duration: 8-10 years), 3428 individuals developed the new-onset AF. The incidence rate ratios for AF were 2.07 (95% confidence interval [CI] = 1.93-2.23) and 1.78 (95% CI = 1.30-2.44) in HD and PD groups, respectively. After we adjusted for age, gender, and comorbidities, the hazard ratios for the AF risk were 1.46 (95% CI = 1.32-1.61) and 1.32 (95% CI = 1.00-1.83) in HD and PD groups, respectively. ESRD patients with a history of certain comorbidities including hypertension, diabetes mellitus, hyperlipidemia, coronary artery disease, heart failure, valvular heart disease, and chronic obstructive pulmonary disease (COPD) have significantly increased risks of AF.This nationwide, population-based study suggests that incidence of AF is increased among dialysis ESRD patients. Furthermore, we have to pay more attention in clinical practice and long-term care for those ESRD patients with a history of certain comorbidities.

Cholesterol Metabolism in CKD

Patients with chronic kidney disease (CKD) have a substantial risk of developing coronary artery disease. Traditional cardiovascular disease (CVD) risk factors such as hypertension and hyperlipidemia do not adequately explain the high prevalence of CVD in CKD. Both CVD and CKD are inflammatory states and inflammation adversely affects lipid balance. Dyslipidemia in CKD is characterized by elevated triglyceride levels and high-density lipoprotein levels that are both decreased and dysfunctional. This dysfunctional high-density lipoprotein becomes proinflammatory and loses its atheroprotective ability to promote cholesterol efflux from cells, including lipid-overloaded macrophages in the arterial wall. Elevated triglyceride levels result primarily from defective clearance. The weak association between low-density lipoprotein cholesterol level and coronary risk in CKD has led to controversy over the usefulness of statin therapy. This review examines disrupted cholesterol transport in CKD, presenting both clinical and preclinical evidence of the effect of the uremic environment on vascular lipid accumulation. Preventative and treatment strategies are explored.

Parameters of glycemic control in type 2 diabetic patients on hemodialysis or peritoneal dialysis: implications for clinical practice

OBJECTIVE

To better explore the relationship between parameters of glycemic control of T2DM in RRT, we studied 23 patients on hemodialysis (HD), 22 on peritoneal dialysis (PD), and compared them with 24 T2DM patients with normal renal function (NRF).

MATERIALS AND METHODS

We performed, on four consecutive days, 10 assessments of capillary blood glucose [4 fasting, 2 pre- and 4 postprandial (post-G) and average (AG)], random glycemia, and HbA1c in all patients.

RESULTS

Preprandial blood glucose was greater in patients on RRT compared with NRF. Correlations between AG and HbA1c were 0.76 for HD, 0.66 for PD, and 0.82 for NRF. The regression lines between AG and HbA1c were similar for patients on HD and with NFR, but they were displaced upward for PD.

CONCLUSION

Similar HbA1c values in PD patients may correspond to greater levels of AG than in HD or NRF patients.

Glomerular filtration rate is associated with burden of coronary atherosclerosis in patients with acute coronary syndrome

We aimed to elucidate the relationship between mild to moderate renal impairements and burden of atherosclerosis in patients with acute coronary syndrome (ACS). A total of 380 patients with ACS were included in the study. Gensini and SYNTAX scores were also calculated. Kidney function was classified based on estimated glomerular filtration rate (eGFR) into stage 1: eGFR >90, stage 2: 60 to 89, and stage 3: 30 to 60 mL/min per 1.73 m(2). Gensini and SYNTAX scores were higher in stages 2 and 3 than in stage 1. Also, the number of diseased vessels, number of critical lesions (>50 and 70%), left main disease, and number of total occlusion vessels were higher in stages 2 and 3 than in stage 1. Multivariate linear regression analysis demonstrated that a decreased eGFR was an independent risk factor for SYNTAX and Gensini scores together with age and male gender.

Association of severity of conjunctival and corneal calcification with all-cause 1-year mortality in maintenance haemodialysis patients

BACKGROUND

Conjunctival and corneal calcification (CCC) is the most common form of metastatic calcification in patients with chronic renal failure. The aim of this study is to investigate if severity of CCC correlates with vascular calcification and mortality in maintenance haemodialysis (MHD) patients.

METHODS

One hundred and nine MHD patients were recruited. CCC was evaluated by external eye photographs, and was graded and scored according to modified Porter and Crombie classification system described by Tokuyama et al. Chest X-ray examination was used to evaluate aortic arch calcification. Geographic, haematological, biochemical and dialysis-related data were obtained. The patients were analysed for traditional and non-traditional risk factors for cardiovascular disease stratified by severity of CCC. All patients were followed up for 1 year to investigate the risks for mortality.

RESULTS

Forty-three, 35 and 31 patients had mild (scores ≤ 4), moderate and severe (scores ≥ 9) CCC at baseline, respectively. With trend estimation, patients with severe CCC had a significantly higher percentage of severe aortic arch calcification. Multiple linear regression analysis showed that hypertension, haemodialysis duration and corrected calcium level were associated with scores of CCC in MHD patients. Moreover, age, corrected calcium-phosphate level, and moderate and severe CCC were associated with grades of aortic arch calcification. At 1-year follow-up, 11 of 109 (10.1%) patients had died. Multivariate Cox proportional hazards model showed that age, corrected calcium and severe CCC were significant risk factors for all-cause 1-year mortality in MHD patients. Each increment of one score of CCC is associated with a 26.4% increased risk for all-cause mortality.

CONCLUSIONS

Severity of CCC, which is easily obtained at bedside, acts as an independent predictor for all-cause 1-year mortality in MHD patients.

Atrial fibrillation in end-stage renal disease: an emerging problem

End-stage renal disease is associated with considerable cardiovascular morbidity and mortality. Atrial fibrillation (AF) is prevalent among dialysis patients and adversely affects the clinical outcome. Vazquez et al. report an increased prevalence and incidence of AF in patients who commence dialysis, and an independent association between arrhythmia and mortality risk. Moreover, they examined clinical and laboratory parameters associated with AF. This population study may fuel research aiming at the development of novel preventive and treatment strategies.

Identification of Inflamed Atherosclerotic Plaque using 123I-Labeled Interleukin-2 Scintigraphy in High-Risk Peritoneal Dialysis Patients: A Pilot Study

Background

Patients with end-stage renal disease (ESRD) suffer from markedly increased cardiovascular morbidity and mortality. Common carotid artery (CCA) intima-media thickness (IMT) assessment and CCA plaque identification using ultrasound are well-recognized tools for identification and monitoring of atherosclerosis. A new method for monitoring the inflammatory status of plaque, namely radiolabeled interleukin-2 (IL-2) scintigraphy, was proposed recently. The aim of this pilot study was to perform 123I-labeled-IL-2 carotid plaque scintigraphy in ESRD patients treated with peritoneal dialysis and to correlate obtained results with ultrasound assessment of CCA and selected inflammatory markers.

Methods

CCA-IMT was measured and CCA plaques were identified by ultrasound in 10 patients (5 women, 5 men; mean age 62.4 ± 10.4 years; median peritoneal dialysis duration 32.5 months, range 12 – 55 months) with advanced cardiovascular comorbidity. Following CCA ultrasound, 123I-labeled IL-2 carotid plaque scintigraphy was performed. Several biomarkers of inflammation and atherosclerosis were also measured in all patients.

Results

Mean target/non-target ratio for focal 123I-IL-2 uptake within the plaque was 3.15 ± 0.54, and mean IMT from the site of the scintigraphy analysis was 0.975 ± 0.337 mm. Highly significant correlation was found between CCA-IMT and a target/non-target ratio for focal 123I-IL-2 uptake in a corresponding artery ( R = 0.92, p = 0.01). However, no significant correlations were found between target/non-target ratio for focal 123I-IL-2 uptake and levels of measured biomarkers.

Conclusions

Our preliminary results suggest potential for identification of an inflamed (vulnerable) plaque using IL-2 scintigraphy in ESRD patients with cardiovascular comorbidities.

PAI-1 and kidney fibrosis

Substantial evidence demonstrates a link of increased plasminogen activator inhibitor-1 (PAI-1) and glomerulosclerosis and kidney fibrosis, providing a novel therapeutic option for prevention and treatment of chronic kidney diseases. Several mechanisms contributing to increased PAI-1 will be addressed, including classic key profibrotic factors such as the renin-angiotensin-system (RAS) and transforming growth factor-beta (TGF-b???and novel molecules identified by proteomic analysis, such as thymosin- b4. The fibrotic sequelae caused by increased PAI-1 in kidney depend not only on its classic inhibition of tissue-type and urokinase-type plasminogen activators (tPA and uPA), but also its influence on cell migration.

Correlates of N-terminal prohormone brain natriuretic peptides in African Americans with hypertensive chronic kidney disease: the African American Study of Kidney Disease and Hypertension

BACKGROUND/AIMS

The N-amino-terminal fragment of the prohormone B-type natriuretic peptide (NT-proBNP) is a marker of cardiac stress and elevated levels are indicative of heart failure. Few correlates of NT-proBNP levels have been identified in persons with moderate chronic kidney disease (CKD), and data from those without heart failure and from African Americans are especially limited.

METHODS

The African American Study of Kidney Disease and Hypertension (AASK) enrolled nondiabetic African Americans with hypertensive kidney disease (glomerular filtration rate [GFR] = 20-65 ml/min/1.73 m(2)) and no evidence of clinical heart failure. NT-proBNP was measured in 982 AASK participants.

RESULTS

In unadjusted analyses, GFR (r = -0.39; p < 0.001), hematocrit (r = -0.21; p < 0.001) and body mass index (BMI; r = -0.07; p = 0.04) were inversely correlated, and systolic blood pressure (r = 0.30; p < 0.001) and log UPCR (r = 0.32; p < 0.001) were positively correlated with log NT-proBNP levels. After adjustment for potential confounders, lower GFR and hematocrit and higher systolic blood pressure and protein:creatinine ratio remained significantly associated with higher NT-proBNP.

CONCLUSION

Lower GFR and hematocrit, and higher urinary protein excretion may be associated with volume expansion in CKD. These results suggest that these processes are associated with increased NT-proBNP in CKD and may play a role in the development of heart failure.

Atrial fibrillation in end-stage renal disease

End-stage renal disease (ESRD) is associated with increased cardiovascular morbidity and mortality. Recent studies indicate that atrial fibrillation (AF) is prevalent among ESRD patients while it adversely affects the clinical outcome. Despite these considerations, AF management in this population is problematic. Notably, most ESRD patients with AF are deprived of the benefits of anticoagulation therapy because of the fear of hemorrhagic complications. This article provides a concise and critical overview of the complex pathophysiology, epidemiology, and discusses the clinical issues regarding the emerging association between ESRD and AF.

Comparison of coronary atherosclerotic volume in patients with glomerular filtration rates < or = 60 versus > 60 ml/min/1.73 m(2): a meta-analysis of intravascular ultrasound studies

The relation between glomerular filtration rate (GFR) <60 ml/min/1.73 m(2) and the extent and progression of coronary atherosclerosis in 989 subjects with coronary artery disease was investigated. Despite being older, more likely to be women, and having a history of hypertension, diabetes, and bypass surgery, total atheroma volume and percent atheroma volume in subjects with a low GFR did not differ from subjects with a GFR >60 ml/kg/min. Similarly, there was no difference in progression rates of total atheroma volume and percent atheroma volume in patients with GFRs lower and higher than 60 ml/min/1.73 m(2) in response to a high rate of use of established preventive therapies. In conclusion, findings suggest that the increased incidence of clinical events in patients with impaired renal function may result from factors other than atherosclerotic burden.

Measuring filtration function in clinical practice

PURPOSE OF REVIEW

The global prevalence of chronic kidney disease is increasing, as are its complications. Central to the diagnosis, evaluation and management of chronic kidney disease is the estimation of glomerular filtration rate. This article summarizes the various equations used to estimate filtration function and the performance of each in clinical practice.

RECENT FINDINGS

During the past year the prediction equations to estimate glomerular filtration rate, especially the Modification of Diet in Renal Disease Study equation, continued to receive much interest. Many studies have compared the performance of the Modification of Diet in Renal Disease Study equation and the Cockcroft-Gault equation. The performance of these equations in various patient populations, such as patients with advanced heart failure, diabetic patients, renal transplantation patients, and the healthy general population, has been extensively studied. Overall, the Modification of Diet in Renal Disease Study equation has had an acceptable validity and has outperformed the Cockcroft-Gault equation in the various populations, but with some limitations that the physician should account for in clinical practice.

SUMMARY

The use of the prediction equations to estimate glomerular filtration rate, especially the Modification of Diet in Renal Disease Study equation, should be implemented more frequently in clinical practice. An ever increasing number of studies has validated its use in different patient populations.

Folic acid therapy reduces plasma homocysteine levels and improves plasma antioxidant capacity in hemodialysis patients

OBJECTIVE

We evaluated the effects of folic acid on homocysteine levels and oxidative stress in 46 stable patients on hemodialysis.

METHODS

This double-blind, placebo-controlled, randomized trial assessed the effects of 6 mo of 10 mg of folic acid (26 patients) or placebo (20 patients) given three times weekly after each dialysis under nurse supervision on homocysteine levels, total plasma antioxidant capacity, and hydroperoxide plasma levels.

RESULTS

Folic acid treatment normalized plasma homocysteine levels in most patients, significantly increased total plasma antioxidant capacity levels, but had no significant effect on hydroperoxide levels. Placebo treatment had no statistically significant effect on the three parameters.

CONCLUSION

The folic acid therapy protocol effectively lowered plasma homocysteine levels and improved the total plasma antioxidant capacity in hemodialysis patients. Further studies are required to assess the usefulness of folic acid for decreasing cardiovascular mortality in patients with chronic kidney disease.

Kidney function estimating equations: where do we stand?

PURPOSE OF REVIEW

Estimation of the glomerular filtration rate (GFR) is central to the diagnosis, evaluation and management of chronic kidney disease. This review summarizes recent data on the performance of equations using serum creatinine to estimate the GFR, particularly the Modification of Diet in Renal Disease (MDRD) Study equation.

RECENT FINDINGS

During 2005 GFR estimation has received substantial attention with a focus on comparing the MDRD Study equation with the Cockcroft-Gault equation. Several large studies (n>500) have appeared. Most studies discuss creatinine calibration but few were able to standardize measurements. Studies that did calibrate the creatinine had improved performance. Overall, the MDRD Study equation performed well in populations with a low range of GFR and often outperformed the Cockcroft-Gault equation. Both equations have lower precision in high GFR populations, and the MDRD equation under-estimated the GFR in a number of studies. Efforts are underway to develop improved prediction equations by pooling data across many study populations.

SUMMARY

Equations for estimating the GFR from serum creatinine are useful for systematic staging of chronic kidney disease. The MDRD Study equation and systematic creatinine assay calibration improve the level of precision and accuracy in many settings. GFR estimates are less useful in the normal range of GFR, however, and are sensitive to the population under study.

Clinical assessment of endothelial dysfunction: combine and rule

PURPOSE OF REVIEW

To briefly survey the literature for the past 2-3 years on the subject of diagnostic and prognostic markers of endothelial cell dysfunction.

RECENT FINDINGS

Established and emerging techniques to detect endothelial cell dysfunction are divided into two large families: (1) functional and structural markers of endothelial cell dysfunction, and (2) surrogate markers of endothelial cell dysfunction. The first category includes high-resolution Doppler studies of conduit arteries, laser Doppler flowmetry of cutaneous microvasculature, and measurements of arterial stiffness and intima: media thickness. The second category of tests provides brief descriptions of detection of oxidative stress, inflammation, coagulation abnormalities, circulating endothelial cells and microparticles. I also focus on integration of various techniques and some novel genomic, proteomic and metabolomic tests.

SUMMARY

This snapshot of existing and emerging technologies diagnosing endothelial cell dysfunction is intended to provide the foundation for the future (a) development of personalized noninvasive screening of endothelial function, and (b) delineation of preclinical diagnostic biomarkers heralding cardiovascular complications.