Risk factors associated with valvular calcification in patients with chronic kidney disease. Analysis of NEFRONA study

INTRODUCTION

Patients with chronic kidney disease (CKD) are at high risk of cardiovascular morbidity and mortality. Subclinical cardiac structural alterations have prognostic value in these patients. The aim was to analyse the prevalence of valvular calcification, the evolution and the relationship with different risk factors.

MATERIAL AND METHODS

Part of the sample of the NEFRONA study was randomly selected. Aortic and mitral valve calcification were analysed in echocardiograms performed at the baseline visit and at 24 months.

RESULTS

We included 397 patients, the estimated basal glomerular filtrate (eGFR) was 33 ml/min with significant decrease to 30.9 ml/min. There was an increase in the area of carotid and femoral plaque, as well as an increase in patients with aortic and mitral calcification at 24 months. A positive association of mitral calcification at 24 months with age, ankle-brachial index (ABI) and calcium-phosphorus product (CaxP) at baseline visit was observed, without association with eGFR. Aortic calcification at 24 months was positively associated with age, phosphorous and total carotid plaque area at baseline, with no relationship to eGFR.

CONCLUSIONS

A significant prevalence of valvular calcification was observed in patients with CKD without known cardiovascular disease.Two-year progression was observed independently of the eGFR. Patients with higher risk of mitral valve calcification were those with older age, higher ABI and CaxP product. Patients with a higher risk of aortic calcification were those with older age, higher phosphorous levels and larger area of carotid plaque. Identifying these higher risk patients would help to avoid future cardiovascular events intensifying follow-ups.

[Risk factors associated with valvular calcification in patients with chronic kidney disease. Analysis of NEFRONA Study]

INTRODUCTION

Patients with chronic kidney disease (CKD) are at high risk of cardiovascular morbidity and mortality. Subclinical cardiac structural alterations have prognostic value in these patients. The aim was to analyse the prevalence of valvular calcification, the evolution and the relationship with different risk factors.

MATERIAL AND METHODS

Part of the sample of the NEFRONA study was randomly selected. Aortic and mitral valve calcification were analysed in echocardiograms performed at the baseline visit and at 24 months.

RESULTS

We included 397 patients, the estimated basal glomerular filtrate (eGFR) was 33ml/min with significant decrease to 30.9ml/min. There was an increase in the area of carotid and femoral plaque, as well as an increase in patients with aortic and mitral calcification at 24 months. A positive association of mitral calcification at 24 months with age, ankle-brachial index (ABI) and calcium-phosphorus product (CaxP) at baseline visit was observed, without association with eGFR. Aortic calcification at 24 months was positively associated with age, phosphorous and total carotid plaque area at baseline, with no relationship to eGFR.

CONCLUSIONS

A significant prevalence of valvular calcification was observed in patients with CKD without known cardiovascular disease.Two-year progression was observed independently of the eGFR. Patients with higher risk of mitral valve calcification were those with older age, higher ABI and CaxP product. Patients with a higher risk of aortic calcification were those with older age, higher phosphorous levels and larger area of carotid plaque. Identifying these higher risk patients would help to avoid future cardiovascular events intensifying follow-ups.

Circulating ADAMs are associated with renal and cardiovascular outcomes in chronic kidney disease patients

BACKGROUND

A disintegrin and metalloproteinase (ADAM) 17, also known as tumour necrosis factor α-converting enzyme (TACE), is a metalloproteinase that releases the ectodomains of most growth factors, cytokines, receptors and enzymes and has been associated with the presence of chronic kidney disease (CKD) and cardiovascular (CV) disease. The role of circulating ADAMs in the progression of renal function and CV events in CKD patients is unknown.

METHODS

A total of 2570 subjects from an observational and multicentre study with CKD Stages 3-5, CKD Stage 5D and controls without any history of CV disease were studied. Circulating ADAM activity was assessed using a fluorometric technique. Progression of renal disease was defined as a 30% increase in serum creatinine or dialysis requirement after 24 months of follow-up. CV outcomes were assessed after 48 months of follow-up.

RESULTS

Patients with advanced CKD had higher ADAM activity as compared with patients with moderate CKD or controls. Male patients with progression of CKD had higher ADAM levels at baseline compared with patients with stable renal function {22.19 relative fluorescence units/μL/h [95% confidence interval (CI) 11.22-37.32] versus 12.15 (7.02-21.50)}. After multivariate adjustment, higher ADAM activity was identified as a risk factor for progression of CKD in male patients [30% increase in the creatinine odds ratio (OR) 2.72 (95% CI 1.58-4.68), P < 0.001; dialysis requirement OR 3.00 (95% CI 1.65-5.46), P < 0.001; dialysis requirement or 30% increase in the creatinine OR 3.15 (95% CI 2.06-4.81), P < 0.001]. ADAM activity was also identified as an independent risk factor for CV events [hazard ratio (HR) 1.68 (95% CI 1.20-2.36), P = 0.003].

CONCLUSIONS

High ADAMs activity levels are independently associated with CKD progression in males and with CV events in CKD patients.

Automatic Methods for Carotid Contrast-Enhanced Ultrasound Imaging Quantification of Adventitial Vasa Vasorum

Adventitial vasa vasorum are physiologic microvessels that nourish artery walls. In the presence of cardiovascular risk factors, these microvessels proliferate abnormally. Studies have reported that they are the first stage of atheromatous disease. Contrast-enhanced ultrasound (CEUS) of the carotid allows direct, quantitative and non-invasive visualization of the adventitial vasa vasorum. Hence, the development of computer-assisted methods that speed image analysis and eliminate user subjectivity is important. We developed methods for automatic analyses and quantification of vasa vasorum neovascularization in CEUS and tested these methods in a cohort of 186 individuals, 63 of whom were healthy volunteers. We implemented alternative automatic strategies for using the images to stratify patients according to their risk group and compare the strategies with respect to diagnostic performance. An automatic single-parameter strategy performs less effectively than the corresponding Arcidiacono method based on manual interpretation of the images (68 < area under the receiver operating characteristic curve [AUROC] for the manual Arcidiacono method < 82; 60 < AUROC for the automatic single-parameter strategy < 63). However, by use of additional image parameters, an automatic multiparameter strategy has significantly improved performance with respect to the manual Arcidiacono method (78 < AUROC < 90). The automatic multiparameter strategy is a valuable alternative to the manual Arcidiacono method, improving both diagnostic speed and diagnostic accuracy.

Non-invasive imaging techniques and assessment of carotid vasa vasorum neovascularization: Promises and pitfalls

Carotid adventitia vasa vasorum neovascularization (VVn) is associated with the initial stages of arteriosclerosis and with the formation of unstable plaque. However, techniques to accurately quantify that neovascularization in a standard, fast, non-invasive, and efficient way are still lacking. The development of such techniques holds the promise of enabling wide, inexpensive, and safe screening programs that could stratify patients and help in personalized preventive cardiovascular medicine. In this paper, we review the recent scientific literature pertaining to imaging techniques that could set the stage for the development of standard methods for quantitative assessment of atherosclerotic plaque and carotid VVn. We present and discuss the alternative imaging techniques being used in clinical practice and we review the computational developments that are contributing to speed up image analysis and interpretation. We conclude that one of the greatest upcoming challenges will be the use of machine learning techniques to develop automated methods that assist in the interpretation of images to stratify patients according to their risk.

Association of FGF-2 Concentrations with Atheroma Progression in Chronic Kidney Disease Patients

BACKGROUND AND OBJECTIVES

Atherosclerosis is highly prevalent in CKD. The rate of progression of atherosclerosis is associated with cardiovascular events. Fibroblast growth factor 2 (FGF-2) is a member of the FGF family with potentially both protective and deleterious effects in the development of atherosclerosis. The role of circulating FGF-2 levels in the progression of atherosclerosis in CKD is unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We used a multicenter, prospective, observational cohorts study of 481 patients with CKD. We determined the presence of atheroma plaque in ten arterial territories by carotid and femoral ultrasounds. Progression of atheromatosis was defined as an increase in the number of territories with plaque after 24 months. Plasma levels of FGF-2 were measured by multiplex analysis. A multivariable logistic regression analysis was performed to determine whether plasma FGF-2 levels were associated with atheromatosis progression.

RESULTS

Average age of the population was 61 years. The percentage of patients in each CKD stage was 51% in stage 3, 41% in stages 4-5, and 8% in dialysis. A total of 335 patients (70%) showed plaque at baseline. Atheromatosis progressed in 289 patients (67%). FGF-2 levels were similar between patients with or without plaque at baseline (79 versus 88 pg/ml), but lower in patients with atheromatosis progression after 2 years (78 versus 98 pg/ml; P<0.01). In adjusted analyses, higher plasma FGF-2 was associated with lower risk of atheromatosis progression (odds ratio [OR], 0.86; 95% confidence interval [95% CI], 0.76 to 0.96; per 50 pg/ml increment). Analysis of FGF-2 in tertiles showed that atheroma progression was observed for 102 participants in the lowest tertile of FGF-2 (reference group), 86 participants in the middle tertile of FGF-2 (adjusted OR, 0.70; 95% CI, 0.40 to 1.20), and 74 participants in the lowest tertile of FGF-2 (adjusted OR, 0.48; 95% CI, 0.28 to 0.82).

CONCLUSIONS

Low FGF-2 levels are independently associated with atheromatosis progression in CKD.

Correction to: Type 2 diabetes-associated carotid plaque burden is increased in patients with retinopathy compared to those without retinopathy

The author found errors in Table 1 after publication of the original article [1].

Combination of biomarkers of vascular calcification and sTWEAK to predict cardiovascular events in chronic kidney disease

BACKGROUND AND AIMS

Vascular calcification (VC) and atherosclerosis are associated with an increased cardiovascular morbimortality in chronic kidney disease (CKD). Osteoprotegerin (OPG) and osteopontin (OPN) are involved in both VC and CKD. Soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) has been related to cardiovascular disease. We hypothesized that OPG, OPN and sTWEAK levels may be associated with a higher prevalence of cardiovascular outcomes in patients with CKD.

METHODS

The presence of calcified or non-calcified atherosclerotic plaques was assessed in 1043 stage 3 to 5D CKD patients from The NEFRONA Study. Biochemical measurements and OPG, OPN and sTWEAK serum levels were analyzed. Patients were followed for cardiovascular outcomes (41 ± 16 months).

RESULTS

At recruitment, 26% of CKD patients had VC. The adjusted odds ratios for having VC were 2.22 (1.32-3.75); p=.003 for OPG, and 0.45 (0.24-0.84); p=.01 for sTWEAK concentrations. After follow-up, 95 CV events occurred. In a Cox model, patients with OPG or OPN above and sTWEAK below their optimal cut-off points had an adjusted higher risk of cardiovascular events [HR: 2.10 (1.49-3.90); p=.02; 1.65 (1.02-2.65); p=.04; 2.05 (1.28-3.29), p=.003; respectively]. When CKD patients were grouped according to the number of biomarkers above (OPG and OPN) or below (sTWEAK) their cut-off points, the combination of these biomarkers showed the highest risk for cardiovascular events [HR: 9.46 (3.80-23.5) p < .001]. A composite score of these three biomarkers increased the C-statistic and net reclassification index beyond conventional risk factors and VC.

CONCLUSIONS

The combination of OPG, OPN and sTWEAK increased the predictability of cardiovascular outcomes.

Factors influencing pathological ankle-brachial index values along the chronic kidney disease spectrum: the NEFRONA study

Background

The ankle-brachial index (ABI) is widely used to diagnose subclinical peripheral artery disease (PAD) in the general population, but data assessing its prevalence and related factors in different chronic kidney disease (CKD) stages are scarce. The aim of this study is to evaluate the prevalence and associated factors of pathological ABI values in CKD patients.

Methods

NEFRONA is a multicentre prospective project that included 2445 CKD patients from 81 centres and 559 non-CKD subjects from 9 primary care centres across Spain. A trained team collected clinical and laboratory data, performed vascular ultrasounds and measured the ABI.

Results

PAD prevalence was higher in CKD than in controls (28.0 versus 12.3%, P < 0.001). Prevalence increased in more advanced CKD stages, due to more patients with an ABI ≥1.4, rather than ≤0.9. Diabetes was the only factor predicting both pathological values in all CKD stages. Age, female sex, carotid plaques, higher carotid intima-media thickness, higher high-sensitivity C-reactive protein (hsCRP) and triglycerides, and lower 25-hydroxi-vitamin D were independently associated with an ABI ≤0.9. Higher phosphate and hsCRP, lower low-density lipoprotein (LDL)-cholesterol and dialysis were associated with an ABI ≥1.4. A stratified analysis showed different associated factors in each CKD stage, with phosphate being especially important in earlier CKD, and LDL-cholesterol being an independent predictor only in Sage 5D CKD.

Conclusions

Asymptomatic PAD is very prevalent in all CKD stages, but factors related to a low or high pathological ABI differ, revealing different pathogenic pathways. Diabetes, dyslipidaemia, inflammation and mineral-bone disorders play a role in the appearance of PAD in CKD.

Factors predicting cardiovascular events in chronic kidney disease patients. Role of subclinical atheromatosis extent assessed by vascular ultrasound

Patients with chronic kidney disease (CKD) have an increased incidence of cardiovascular events (CVE). The contribution of subclinical atheromatosis extent, including femoral arteries, to CVE in CKD patients has not been investigated. In this paper, we examine the prognostic value of subclinical atheromatosis extent, assessed as the number of arterial territories with plaque, in predicting the incidence of major and minor CVE. The NEFRONA is a multicenter, prospective cohorts study that recruited 2445 CKD subjects and 559 controls, free from previous cardiovascular disease, in 81 medical centers across Spain. The presence of atheroma plaque was assessed by arterial ultrasound in ten arterial territories (carotid and femoral). The predictive power of the presence or absence of atheroma plaque in any territory was compared with the quantification of atheroma extent as the number of territories with plaque. During the median follow up of 48 months, 216 CVE were reported. Factors predicting the incidence of CVE in the whole cohort were being male, CKD patient, lower levels of 25(OH) vitamin D, higher levels of cholesterol and the extent of subclinical atheromatosis, yielding a higher concordance (C) index than the presence or absence of plaque. In stratified analysis including specific factors of CKD patients not on dialysis, the variables predicting CVE were the same as in the whole cohort, plus higher levels of potassium. Again, the inclusion of the information about atheromatosis as number of territories with plaque, presented a higher C index than the presence or absence of plaque. In the dialysis population, significant variables were older age, diabetes, dialysis vintage and higher levels of cholesterol and phosphate. In this case the higher C index was obtained with the information about plaque presence.

Subclinical atheromatosis extent, including femoral arteries, influences CVE in CKD and its detection could improve the prediction of cardiovascular events.

Preclinical carotid atherosclerosis in patients with latent autoimmune diabetes in adults (LADA), type 2 diabetes and classical type 1 diabetes

BACKGROUND

LADA is probably the most prevalent form of autoimmune diabetes. Nevertheless, there are few data about cardiovascular disease in this group of patients. The aim of this study was to investigate the frequency of carotid atherosclerotic plaques in patients with LADA as compared with patients with classic type 1 diabetes and type 2 diabetes.

METHODS

Patients with LADA were matched for age and gender in different proportions to patients with type 2 diabetes, and classic type 1 diabetes. None of the patients had clinical cardiovascular disease. All subjects underwent B-mode carotid ultrasound to detect atheroma plaques. Demographics were obtained from all subjects.

RESULTS

We included 71 patients with LADA, 191 patients with type 2 diabetes and 116 patients with type 1 diabetes. Carotid atherosclerosis was more frequent in patients with LADA compared with type 2 diabetes (73.2% vs. 56.9%, P = 0.0018) and classic type 1 diabetes (57.1%, P = 0.026); these changes occurred despite healthier macrovascular risk profiles in the former. Age (P < 0.001), smoking (P = 0.003) and hypertension (P = 0.019) were independently associated with carotid atherosclerosis. Multiple plaques were also more frequent in patients with LADA as compared with classic type 1 diabetes and type 2 diabetes (45.1% and 33.6% vs. 27.2%, respectively, P = 0.022). The frequency of carotid plaques increased with increasing diabetes duration in LADA patients compared with type 2 diabetes (85.7% vs. 58.8%, inverse OR 5.72 [1.5-21.8]; P = 0.009).

CONCLUSIONS

LADA patients do not present with less carotid atherosclerosis than patients with type 1 and type 2 diabetes. Their macrovascular risk occurs despite a healthier macrovascular risk profile than those patients with type 2 diabetes.

A Convolutional Neural Network for Automatic Characterization of Plaque Composition in Carotid Ultrasound

Characterization of carotid plaque composition, more specifically the amount of lipid core, fibrous tissue, and calcified tissue, is an important task for the identification of plaques that are prone to rupture, and thus for early risk estimation of cardiovascular and cerebrovascular events. Due to its low costs and wide availability, carotid ultrasound has the potential to become the modality of choice for plaque characterization in clinical practice. However, its significant image noise, coupled with the small size of the plaques and their complex appearance, makes it difficult for automated techniques to discriminate between the different plaque constituents. In this paper, we propose to address this challenging problem by exploiting the unique capabilities of the emerging deep learning framework. More specifically, and unlike existing works which require a priori definition of specific imaging features or thresholding values, we propose to build a convolutional neural network (CNN) that will automatically extract from the images the information that is optimal for the identification of the different plaque constituents. We used approximately 90 000 patches extracted from a database of images and corresponding expert plaque characterizations to train and to validate the proposed CNN. The results of cross-validation experiments show a correlation of about 0.90 with the clinical assessment for the estimation of lipid core, fibrous cap, and calcified tissue areas, indicating the potential of deep learning for the challenging task of automatic characterization of plaque composition in carotid ultrasound.

Circulating angiotensin converting enzyme 2 activity as a biomarker of silent atherosclerosis in patients with chronic kidney disease

BACKGROUND AND AIMS

Circulating Angiotensin Converting Enzyme 2 (ACE2) activity in chronic kidney disease (CKD) patients without previous history of cardiovascular disease (CVD) has been associated with classical risk factors (older age, diabetes and male gender). Furthermore, silent atherosclerosis has been described as a pathological link between CKD and CVD. We analyzed baseline ACE2 activity in non-dialysis CKD stages 3-5 (CKD3-5) patients as a biomarker of renal progression, silent atherosclerosis and CV events after 2 years of follow-up.

METHODS

Prospective study of 1458 CKD3-5 subjects without any previous CV event included in the Spanish multicenter NEFRONA study. Association between baseline circulating ACE2 activity and renal parameters, carotid/femoral echography, atheromatous disease, ankle-brachial index, intima-media thickness, need of renal replacement therapy, cardiovascular events and mortality at 24 months of follow-up were analyzed.

RESULTS

Patients with an increase in the number of territories with plaques at 24 months showed significantly higher levels of baseline ACE2 activity as compared to stable patients (29.6 (20.6-47.6)RFU/μL/h versus 35.7 (24.5-56), p < 0.001). Multivariate linear regression analysis showed that male gender, pathological ankle-brachial index and progressive silent atherosclerosis defined as an increased number of territories with plaques at 24 months were associated with increased baseline ACE2 activity. Male gender, older age, diabetes, smoking and increased baseline circulating ACE2 were independent predictors of atherosclerosis at 24 months of follow-up.

CONCLUSIONS

In CKD3-5 patients, higher circulating ACE2 activity at baseline is associated with higher risk for silent atherosclerosis, suggesting that ACE2 may serve as a biomarker to predict CV risk before CVD is established.

Soluble TWEAK and Major Adverse Cardiovascular Events in Patients with CKD

BACKGROUND AND OBJECTIVES

Soluble TNF-like weak inducer of apoptosis (sTWEAK) is a proinflammatory cytokine belonging to the TNF superfamily. sTWEAK concentrations have been associated with the presence of CKD and cardiovascular disease (CVD). We hypothesized that sTWEAK levels may relate to a higher prevalence of atherosclerotic plaques, vascular calcification, and cardiovascular outcomes observed in patients with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A 4-year prospective, multicenter, longitudinal study was conducted in 1058 patients with CKD stages 3-5D (mean age =58±13 years old; 665 men) but without any history of CVD from the NEFRONA Study (a study design on the prevalence of surrogate markers of CVD). Ankle-brachial index and B-mode ultrasound were performed to detect the presence of carotid and/or femoral atherosclerotic plaques together with biochemical measurements and sTWEAK assessment. Patients were followed for cardiovascular outcomes (follow-up of 3.13±1.15 years).

RESULTS

Patients with more advanced CKD had lower sTWEAK levels. sTWEAK concentrations were independently and negatively associated with carotid intima-media thickness. sTWEAK levels were lower in patients with carotid atherosclerotic plaques but not in those with femoral plaques. After adjustment by confounders, the odds ratio (OR) for presenting carotid atherosclerotic plaques in patients in the lowest versus highest tertile of sTWEAK was 4.18 (95% confidence interval [95% CI], 2.89 to 6.08; P<0.001). Furthermore, sTWEAK levels were lower in patients with calcified carotid atherosclerotic plaques. The OR for presenting calcified carotid plaques was 1.77 (95% CI, 1.06 to 2.93; P=0.02) after multivariable adjustment. After the follow-up, 41 fatal and 68 nonfatal cardiovascular events occurred. In a Cox model, after controlling for potential confounding factors, patients in the lowest tertile of sTWEAK concentrations had a higher risk of fatal and nonfatal cardiovascular events (hazard ratio [HR], 2.40; 95% CI, 1.33 to 4.33; P=0.004) and cardiovascular mortality (HR, 2.67; 95% CI, 1.05 to 6.76; P=0.04).

CONCLUSIONS

Low sTWEAK levels were associated with the presence of carotid atherosclerotic plaques in patients with CKD. Additionally, lower sTWEAK levels were associated with a higher risk of cardiovascular morbidity and mortality.

Left carotid adventitial vasa vasorum signal correlates directly with age and with left carotid intima-media thickness in individuals without atheromatous risk factors

Objective

The early identification of the onset of subclinical atheromatosis is essential in reducing the high mortality risk from cardiovascular disease (CVD) worldwide. Although carotid intima-media thickness (cIMT) is the most commonly used early predictor of ongoing atherosclerosis, an experimental model of atherosclerosis, demonstrated that increases in adventitial microvessels (vasa vasorum (VV)) precede endothelial dysfunction. Using the reported accuracy of contrast-enhanced ultrasound (CEU) to measure carotid adventitial VV, this study assessed whether measurements of carotid adventitial VV serve as a marker of subclinical atherosclerotic lesions in a control population with none of the classical risk factors for CVD.

Methods and results

Measurements of cIMT (B-mode ultrasound) and adventitial VV (CEU) were conducted in 65 subjects, 30–70 years old, 48% men, with none of the classical risk factors for CVD. Adventitial VV strongly correlated with its own cIMT only in the left carotid artery. Importantly, the left carotid adventitial VV directly correlated with age.

Conclusions

The increases with age in left carotid adventitial VV in individuals with zero risk for atheromatosis suggest that the measurement of carotid adventitial VV could be an accurate and sensitive marker for the diagnosis of subclinical atheromatosis and therefore a prominent tool for monitoring the efficacy of anti-atheromatous therapies.

Circulating angiotensin-converting enzyme 2 activity in patients with chronic kidney disease without previous history of cardiovascular disease

Background

Patients with cardiovascular (CV) disease have an increased circulating angiotensin-converting enzyme 2 (ACE2) activity, but there is little information about changes in ACE2 in chronic kidney disease (CKD) patients without history of CV disease. We examined circulating ACE2 activity in CKD patients at stages 3–5 (CKD3-5) and in dialysis (CKD5D) without any history of CV disease.

Methods

Circulating ACE2 activity was measured in human ethylenediamine-tetraacetic acid (EDTA)-plasma samples from the NEFRONA study (n = 2572): control group (CONT) (n = 568), CKD3-5 (n = 1458) and CKD5D (n = 546). Different clinical and analytical variables such as gender; age; history of diabetes mellitus (DM), dyslipidemia and hypertension; glycaemic, renal, lipid and anaemia profiles; vitamin D analogues treatment and antihypertensive treatments (angiotensin-converting enzyme inhibitor and angiotensin receptor blockade) were analysed. Circulating ACE2 and ACE activities were measured using modified fluorimetric assay for EDTA-plasma samples, where zinc chloride was added to recover enzymatic activity.

Results

In CKD3-5 and CKD5D, significant decrease in circulating ACE2 activity was observed when compared with CONT, but no differences were found between CKD3-5 and CKD5 when performing paired case-control studies. By multivariate linear regression analysis, male gender and advanced age were identified as independent predictors of ACE2 activity in all groups. Diabetes was identified as independent predictor of ACE2 activity in CKD3-5. Significant increase in the activity of circulating ACE was found in CKD3-5 and CKD5D when compared with CONT and in CKD5D when compared with CKD3-5. By multiple regression analysis, female gender and younger age were identified as independent predictors of ACE activity in CONT and CKD3-5. Diabetes was also identified as an independent predictor of ACE activity in CKD3-5 patients.

Conclusions

Circulating ACE2 and ACE activities can be measured in human EDTA-plasma samples with zinc added to recover enzymatic activity. In a CKD population without previous history of CV disease, ACE2 activity from human EDTA-plasma samples directly correlated with the classical CV risk factors namely older age, diabetes and male gender. Our data suggest that circulating ACE2 is altered in CKD patients at risk for CV event.

Type 2 diabetes-associated carotid plaque burden is increased in patients with retinopathy compared to those without retinopathy

Background

Cardiovascular disease (CVD) is the leading cause of mortality among subjects with type 2 diabetes (T2D), and diabetic retinopathy (DR) has been associated with an increased risk for CVD. The present study was designed to test the concept that T2D patients with DR, but without previous cardiovascular (CV) events and with normal renal function, have an increased atherosclerotic burden compared with patients without DR.

Methods

A cross-sectional study was performed using patients with normal renal function (estimated glomerular filtration rate (eGFR) >60 ml/min) and without previous CV events. A total of 312 patients (men, 51%; mean age, 57 yrs; age range 40–75 yrs) were included in the study; 153 (49%) of the patients had DR. B-mode carotid ultrasound imaging was performed for all of the study subjects to measure the carotid intima-media thickness (cIMT) and carotid plaques in the common carotid artery (CCA), bifurcation and internal carotid artery (ICA).

Results

The percentage of carotid plaques in T2D patients with DR was higher than in T2D patients without DR (68% vs. 52.2%, p = 0.0045), and patients with DR had a higher prevalence of ≥2 carotid plaques (44.4% vs. 21.4%; p < 0.0001). No differences were observed in the cIMT measured at different carotid regions between the patients with or without DR. Using multivariate logistic regression (adjustment for major risk factors for atherosclerosis), DR was independently associated with mean-internal cIMT (p = 0.0176), with the presence of carotid plaques (p = 0.0366) and with carotid plaque burden (≥2 plaques; p < 0.0001).

Conclusions

The present study shows that DR in T2D patients without CVD and with normal renal function is associated with a higher atherosclerotic burden (presence and number of plaques) in the carotid arteries. These patients may be at a higher risk for future CV events; therefore, an ultrasound examination of the carotid arteries should be considered in patients with DR for more careful and individualised CV assessment and follow-up.

Association of serum phosphorus with subclinical atherosclerosis in chronic kidney disease. Sex makes a difference

BACKGROUND

Cardiovascular disease is the leading cause of mortality in chronic kidney disease (CKD). Serum phosphate has been associated to cardiovascular disease in the general population and this effect seems to be different according to sex. In the present study we analyze the effect of phosphate on subclinical atherosclerosis in the NEFRONA population and its effect depending on sex.

DESIGN

Carotid ultrasound assessing the presence of plaques was performed by an itinerant team in 1687 CKD patients not in dialysis without previous cardiovascular events. Standard blood test and anthropometrical parameters were also recorded.

RESULTS

Multivariate linear regression to model phosphate levels in patients with CKD showed an interaction of sex with age. Thus, among men, serum phosphate levels declined significantly with age almost linearly. Serum phosphate levels in women under the age of 40-45 years overlapped with those in men and then stayed above, showing and overall constant relationship. Multivariate logistic regression analysis showed that higher phosphate levels associated with a higher risk of presenting atheromatous plaque. This risk however was different according to sex. In men, phosphate levels within the normal range associated with an increased risk of subclinical atheromatosis whereas in women this risk only increased with serum levels over the normal range.

CONCLUSIONS

This study demonstrates that phosphate levels are associated with the presence of subclinical atheromatosis in a large CKD population. This effect of phosphate on subclinical atheromatosis was different according to sex, suggesting that a recommended serum phosphate levels could be different for male than for female CKD patients.

Observational multicenter study to evaluate the prevalence and prognosis of subclinical atheromatosis in a Spanish chronic kidney disease cohort: baseline data from the NEFRONA study

BACKGROUND

Cardiovascular events (CVE) are more prevalent in chronic kidney disease (CKD) than in general population, being the main cause of morbimortality. Specific risk factors related to CKD have been suggested, because traditional factors do not fully explain this increase in cardiovascular disease rates. However, the role of atheromatosis, its pathogenesis and evolution are still unclear. The potential use of diagnostic tests to detect subclinical atheromatosis has to be determined.

METHODS

NEFRONA is a prospective multicenter cohort study. 2445 CKD subjects were enrolled from 81 Spanish hospitals and dialysis clinics, from 2010 to 2012. Eligibility criteria included: 18 to 74 years old, CKD stage 3 or higher, and no previous CVE. 559 non-CKD controls were also recruited. Demographical, clinical and analytical data were collected. Carotid and femoral ultrasounds were performed by a single trained team to measure carotid intima-media thickness (cIMT) and detect atheromatous plaques. Ankle-brachial index (ABI) was measured.

RESULTS

Differences in age, sex and prevalence and control of cardiovascular risk factors were found between controls and CKD patients. These differences are similar to those described in epidemiological studies.No difference was found regarding cIMT between controls and CKD (when subjects with plaques in common carotid arteries were omitted); earlier CKD stages had higher values. CKD patients had a higher rate of atheromatous plaques, with no difference between stages in the unadjusted analysis. A group of patients had plaques in femoral arteries but were plaque-free in carotid arteries, and would have gone underdiagnosed without the femoral study. The percentage of pathologic ABI was higher in CKD, with higher prevalence in more advanced stages, and a higher rate of ABI >1.4 than <0.9, suggesting more vascular calcification.

CONCLUSIONS

NEFRONA is the first large study describing the actual prevalence of subclinical atheromatosis across different CKD stages. There is a very high rate of atheromatous plaques and pathologic ABI in CKD. Prospective data will add important information to the pathogenesis and evolution of atheromatosis in CKD, compared to non-CKD subjects.

The role of carotid ultrasound in assessing carotid atherosclerosis in individuals at low-to-intermediate cardiovascular risk

INTRODUCTION AND OBJECTIVES

Detection of carotid atherosclerosis might help to better identify individuals susceptible to cardiovascular events. We aimed to quantify the number of participants with carotid atherosclerosis and low-to-intermediate cardiovascular risk according to the traditional risk factor scoring, and therefore with an elevated risk of cardiovascular events.

METHODS

Cross-sectional, observational study performed during a cardiovascular screening program. From a total of 3778 volunteers, low-to-intermediate cardiovascular risk individuals (N=2354) were identified and studied. Physical examination, blood test, and carotid ultrasound followed standard procedures. Common, bulb, and internal carotid arteries were examined and common carotid intima-media thickness was measured. SCORE risk value was calculated for all participants. Univariate and multivariate statistical analysis was performed.

RESULTS

Mean age of participants was 58.9 (15) years, 43.8% were men, 23.7% had hypertension, and 20.5% had hypercholesterolemia. The mean SCORE value was 1.47 (1.4). Both carotid intima-media thickness and the prevalence of carotid plaques increased steadily and significantly (P<.005) as advanced decades of life were analyzed. Variables significantly related with the presence of carotid atherosclerosis were age, male sex, and systolic blood pressure. Interestingly, 592 (25.1%) individuals were reclassified to a higher risk due to the presence of carotid atherosclerosis.

CONCLUSIONS

There was a clear dissociation between cardiovascular risk scoring and the presence of atherosclerosis, because 1 of 4 study participants at low-to-intermediate cardiovascular risk had carotid atherosclerosis.

Large artery calcification on dialysis patients is located in the intima and related to atherosclerosis

BACKGROUND AND OBJECTIVES

Vascular calcification (VC) has a significant effect in cardiovascular diseases on dialysis patients. However, VC is assessed with x-ray-based techniques, which do not inform about calcium localization (intima, media, atherosclerosis-related). The aim of this work is to study VC and its related factors using arterial ultrasound to report the exact location of calcium.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was an observational, cross-sectional, case-control study that included 232 patients in dialysis and 208 age- and sex-matched controls with normal kidney function. Demographic data and laboratory values were collated. Carotid, femoral, and brachial ultrasounds were performed to assess VC and atherosclerosis burden using a standardized protocol.

RESULTS

Cardiovascular risk factors were predominantly found in controls, although the burden of atherosclerosis was higher in the dialysis group. VC was significantly more prevalent in the group of patients on dialysis than control subjects, and in both groups the most prevalent pattern of VC was linear calcification located in the intima of the artery wall. Age and undergoing dialysis (with or without previous cardiovascular diseases) were positively and significantly associated with linear calcification. Conversely, the absence of atherosclerosis and low levels of C-reactive protein and phosphorus significantly impeded the development of linear calcification.

CONCLUSIONS

VC in large, conduit arteries is more prevalent in patients on dialysis than controls and is predominantly located in a linear fashion in the intima of the arteries.

Cardiovascular risk factors underestimate atherosclerotic burden in chronic kidney disease: usefulness of non-invasive tests in cardiovascular assessment

BACKGROUND

Cardiovascular risk scoring (Score) does not specifically address chronic kidney disease (CKD) patients. The aim of our study is to quantify atherosclerosis using carotid ultrasound and ankle-brachial index (ABI) and to assess its additional value in risk scoring.

METHODS

In this cross-sectional, observational study, patients were studied according to a standardized protocol including carotid ultrasound and ABI to determine the atherosclerosis score (AS), ranging from absence of to severe atherosclerosis (AS 0 to AS 3).

RESULTS

We included 409 CKD-affected patients (231 on dialysis, 99 in CKD Stages IV-V and 79 in CKD Stages I-III) and 851 subjects with normal renal function. The presence and severity of atherosclerosis was significantly higher in the CKD group than in the controls at every decade of age studied. Among the CKD-affected subjects, the prevalence of carotid plaques was significantly higher in the dialysis group (78.3%) than in the group in CKD Stages I-III (55.6%, P < 0.001). We identified 174 patients at low-intermediate risk. Among them, 110 (63.2%) presented either moderate (AS 2) or severe (AS 3) atherosclerosis. Variables significantly (P < 0.05) and positively related to atherosclerosis were being on dialysis [OR = 3.40, 95% CI (1.73, 6.78) vs CKD Stages I-III], age [OR = 1.08, 95% CI (1.06-1.11)] and C-reactive protein [OR = 1.04, 95% CI (1.01-1.08)]. Conversely, female sex was negatively related to atherosclerosis [OR = 0.40, 95% CI (0.23-0.71), P = 0.002].

CONCLUSION

The use of carotid ultrasound and ABI identifies atherosclerosis in a population of CKD patients in which risk scoring underestimates atherosclerosis burden.

Safety and Efficacy of Sevelamer in the Treatment of Uncontrolled Hyperphosphataemia of Haemodialysis Patients

BACKGROUND/AIM

The treatment of hyperphosphataemia is of major importance in the management of patients on dialysis. Traditional phosphate binders can be associated with undesirable effects. Recently, a new non-absorbable phosphate-binding polymer, sevelamer hydrochloride, has been available. Clinical information is scarce, and its cost could be a limiting factor for its wider use. No studies have evaluated its usefulness in uncontrolled hyperphosphataemic patients.

METHODS

We identified 34 patients with a maintained serum phosphorus concentration >6.5 mg/dl and/or toxicity related to standard phosphorus-binding treatment (aluminium or calcium based). Sevelamer was added and titrated up fortnightly to achieve phosphorus control. Previous phosphate binders were decreased, whenever possible. The period of the study was 6 months.

RESULTS

Thirteen patients (38%) dropped out because of side effects, mainly related to the gastro-intestinal tract. The efficacy analysis disclosed that the phosphorus concentration decreased from 2.39 +/- 0.48 to 1.84 +/- 0.48 mmol/l (p < 0.001). The mean dose of sevelamer was stabilised at 3.4 +/- 1.8 g/day. The amount of calcium- and aluminium-based phosphate binders could be decreased from 5.1 +/- 3.5 to 3.1 +/- 2.7 g/day (38% decrease) and from 2.4 +/- 1.5 to 1.5 +/- 1.7 g/day (36% decrease), respectively. The Ca x P product was significantly decreased from 5.83 +/- 1.19 to 4.36 +/- 1.12 mmol/l2 (p < 0.001). The total cholesterol concentration decreased from 4.34 +/- 0.9 to 3.98 +/- 0.9 mmol/l (p < 0.01) and the low-density lipoprotein cholesterol level from 2.61 +/- 0.98 to 2.20 +/- 0.77 mmol/l (p < 0.03).

CONCLUSIONS

Sevelamer is an effective phosphate binder that allows a better serum phosphorus control, while allowing a decrease in the dose of calcium- and aluminium-based phosphate binders in these difficult patients. The drawbacks are the high intolerance rate and the price of the product.

Recommendations on percutaneous coronary intervention for the reperfusion of acute ST elevation myocardial infarction

Little information is currently available from the various societies of cardiology on primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI). Since primary PCI is the main method of reperfusion in AMI in many centres, and since of all cardiac emergencies AMI represents the most urgent situation for PCI, recommendations based on scientific evidence and expert experience would be useful for centres practising primary PCI, or those looking to establish a primary PCI programme. To this aim, a task force for primary PCI in AMI was formed to develop a set of recommendations to complement and assist clinical judgment. This paper represents the product of their recommendations.

Collaborative Angiographic Patency Trial Of Recombinant Staphylokinase (CAPTORS II)

AIMS

A fibrinolytic agent more effective than streptokinase available for bolus injection with reasonable cost-effectiveness is a desirable goal. Pilot studies with bolus pegulated staphylokinase (PEG-Sak) have revealed excellent Thrombolysis In Myocardial Infarction (TIMI) 3 60-minute flow.

METHODS AND RESULTS

We evaluated patients with acute ST-elevation myocardial infarction within 6 hours of chest pain onset to determine a dose of PEG-Sak that had at least equal efficacy to recombinant tissue plasminogen activator (rt-PA) while maintaining an acceptable safety profile. After the initial study of 38 patients, of whom 27 received PEG-Sak, enrollment was temporarily halted because 3 patients receiving PEG-Sak had intracranial hemorrhage: 1 at a dose of 0.15 mg/kg and 2 at a dose of 0.05 mg/kg. Overall, 378 patients were studied across a PEG-Sak dose range from 0.01 mg/kg to 0.015 mg/kg, and 122 patients received accelerated rt-PA. At the lowest dose of PEG-Sak studied, 0.01 mg/kg, there was suggestive evidence of attenuation of efficacy; the point estimate for TIMI 3 flow was 24% (95% CI 9%-38%). At doses of 0.01875 to 0.0375 mg/kg (n = 314), TIMI 3 flow rates were 33% (95% CI 27%-38%), whereas the TIMI 3 flow was 41% (95% CI 20%-61%) at the highest PEG-Sak dose studied, 0.05 mg/kg (n = 23), which was similar to that found with rt-PA, 41% (95% CI 32%-50%).

CONCLUSION

The efficacy of PEG-Sak, coupled with its ease of administration, provide further impetus for further study in acute myocardial infarction.

Higher impact of mineral metabolism on cardiovascular mortality in a European hemodialysis population

BACKGROUND

Cardiovascular disease is the main cause of morbidity and mortality among hemodialysis patients. Chronic renal failure influences a number of factors that cause accelerated atherogenesis, with calcium, phosphorus, and PTH playing key roles. Several studies have demonstrated the influence of these factors on all-cause and cardiovascular mortality in the American hemodialysis population. In the present study we evaluated the variables that influence long-term cardiovascular mortality in a European hemodialysis population.

METHODS

One hundred and forty-three hemodialysis patients were followed for six years. Several Cox models were used to study the influence of demographic and biochemical data, and comorbid conditions in cardiovascular survival, with a particular interest in mineral metabolism.

RESULTS

There was an increased risk of cardiovascular death in patients with serum P>6.5 mg/dL (risk ratio [RR], 2.5), PTH>50 pmol/L (RR, 3.9), Ca x P>52 (RR, 2.8), BB or Bb genotype (RR, 3.8), and in diabetics.

CONCLUSION

There is a stronger influence of mineral metabolism on cardiovascular death among European patients when compared to the American population.

BB genotype of the vitamin D receptor gene polymorphism postpones parathyroidectomy in hemodialysis patients

BACKGROUND

Bsml vitamin D receptor (VDR) gene polymorphism has been reported to influence the progression of secondary hyperparathyroidism but it is not known how much the genetic background contributes to the need for parathyroidectomy (PTx). We investigated the influence of VDR gene polymorphism on PTx in patients with different dialysis vintage.

METHODS

We studied 121 parathyroidectomized HD patients ("PTx " group). Patients who had required early parathyroidectomy ("early PTx" group) or late parathyroidectomy ("late PTx" group) were analyzed separately. The cut-off point between these two groups was 89 months (mean time on hemodialysis (HD) before parathyroidectomy). Serum intact parathyroid hormone, calcium, phosphorus and alkaline phosphatase were measured. Bsml genotypes were analyzed by polymerase chain reaction. Statistical analysis was done with univariant analysis of variance (ANOVA) to compare the genotype groups and general factorial ANOVA, entering time on HD as the dependent variable, with genotype, sex, age and chronic renal failure (CRF) etiology as factors. As a control group for the association studies we determined genotypic frequencies in 162 HD patients ("total HD" group), and in a healthy control population of 120 individuals ("healthy" group), tested by contingency table analysis and the chi-square test.

RESULTS

No significant differences were found between the genotypes except for the time on HD. General factorial ANOVA showed that the adjusted means of the time on HD were significantly different for the various genotypes (p = 0.015). The BB genotype was significantly less frequent in the "early PTx " group than in the "total HD" and "late PTx" groups.

CONCLUSIONS

Individuals with the BB genotype can remain longer on HD before they need parathyroidectomy.

Incidence and predictors of bleeding events after fibrinolytic therapy with fibrin-specific agents: a comparison of TNK-tPA and rt-PA

BACKGROUND

Fibrinolytic therapy increases the risk of bleeding events. TNK-tPA (tenecteplase) is a variant of rt-PA with greater fibrin specificity and reduced plasma clearance that can be given as a single bolus. We compared the incidence and predictors of bleeding events after treatment with TNK-tPA and rt-PA.

METHODS AND RESULTS

In the Assessment of the Safety and Efficacy of a New Thrombolytic (ASSENT)-2 trial, 16 949 patients with acute myocardial infarction were randomly assigned a single weight-adjusted bolus of TNK-tPA or a 90-min infusion of rt-PA. A total of 4.66% of patients in the TNK-tPA group experienced major non-cerebral bleeding, in comparison with 5.94% in the rt-PA group (P=0.0002). This lower rate was associated with a significant reduction in the need for blood transfusion (4.25% vs 5.49%, P=0.0003) and was consistent across subgroups. Independent risk factors for major bleeding were older age, female gender, lower body weight, enrolment in the U.S.A. and a diastolic blood pressure <70 mmHg. Females at high risk (age >75 years and body weight <67 kg) were less likely to have major bleeding when treated with TNK-tPA even after other risk factors were taken into account. A total of 0.93% of patients in the TNK-tPA and 0.94% of patients in the rt-PA group experienced an intracranial haemorrhage. Female patients >75 years of age who weighed <67 kg tended to have lower rates of intracranial haemorrhage when treated with TNK-tPA (3/264, 1.14% vs 8/265, 3.02%).

CONCLUSIONS

The increased fibrin specificity and single bolus administration of TNK-tPA do not increase the risk of intracranial haemorrhage but are associated with less non-cerebral bleeding, especially amongst high-risk patients.

Influence of vitamin D receptor gene polymorphisms on mortality risk in hemodialysis patients

The BsmI polymorphism of the vitamin D receptor (VDR) gene influences mineral metabolism and the course of cancers and infections. The poly-A polymorphism is in linkage disequilibrium with BsmI and could be responsible for clinical associations attributed to BsmI. The objective of this work is to study the influence of VDR polymorphisms on survival of 143 prevalent hemodialysis (HD) patients followed up for 4 years. Chi-square test was used to study the association between survival and these polymorphisms. Cox analysis was performed, adjusting for comorbid conditions in the entire HD population, groups of patients on HD therapy for less than 5 and 3 years before entering 4 years of observation, patients without diabetes, and patients treated with calcitriol. Survival was analyzed by means of Kaplan-Meier according to BsmI genotypes. Results showed a strong influence of the BsmI polymorphism on survival. The bb genotype was overrepresented among survivors (45.7%) compared with nonsurvivors (21.6%), and Cox analysis showed a significant influence of age, diabetes, calcitriol treatment, and BsmI polymorphism in all groups (in the entire population, Exp(B): BB, 3.9; and Bb, 3 with respect to bb), and also of phosphorus in patients without diabetes and calcitriol-treated patients. Survival means by Kaplan-Meier were as follows: BB, 983 days; Bb, 1,152 days; and bb, 1,290 days (log-rank P = 0.01). The BsmI polymorphism influences survival in HD patients, whereas the poly-A and FokI polymorphisms do not.