Dyslipidemia and progression of cardiovascular calcification (CVC) in patients with end-stage renal disease (ESRD)

Values of Donor Serum Lipids and Calcium in Predicting Graft Function after Kidney Transplantation: A Retrospective Study

OBJECTIVE

Delayed graft function (DGF) and early graft loss of renal grafts are determined by the quality of the kidneys from the deceased donor. As "non-traditional" risk factors, serum biomarkers of donors, such as lipids and electrolytes, have drawn increasing attention due to their effects on the postoperative outcomes of renal grafts. This study aimed to examine the value of these serum biomarkers for prediction of renal graft function.

METHODS

The present study consecutively collected 306 patients who underwent their first single kidney transplantation (KT) from adult deceased donors in our center from January 1, 2018 to December 31, 2019. The correlation between postoperative outcomes [DGF and abnormal serum creatinine (SCr) after 6 and 12 months] and risk factors of donors, including gender, age, body mass index (BMI), past histories, serum lipid biomarkers [cholesterol, triglyceride, high-density lipoprotein (HDL) and low-density lipoprotein (DL)], and serum electrolytes (calcium and sodium) were analyzed and evaluated.

RESULTS

(1) Donor age and pre-existing hypertension were significantly correlated with the incidence rate of DGF and high SCr level (≥2 mg/dL) at 6 and 12 months after KT (P<0.05); (2) The donor's BMI was significantly correlated with the incidence rate of DGF after KT (P<0.05); (3) For serum lipids, merely the low level of serum HDL of the donor was correlated with the reduced incidence rate of high SCr level at 12 months after KT [P<0.05, OR (95% CI): 0.425 (0.202-0.97)]; (4) The serum calcium of the donor was associated with the reduced incidence rate of high SCr level at 6 and 12 months after KT [P<0.05, OR (95% CI): 0.184 (0.045-0.747) and P<0.05, OR (95% CI): 0.114 (0.014-0.948), respectively].

CONCLUSION

The serum HDL and calcium of the donor may serve as predictive factors for the postoperative outcomes of renal grafts after KT, in addition to the donor's age, BMI and pre-existing hypertension.

Do trace elements play a role in coronary artery calcification in hemodialysis patients?

PURPOSE

Abnormalities of trace elements have previously been linked to inflammatory processes in hemodialysis (HD) patients. We aimed to establish the trace element status of maintenance HD patients, to investigate the relationship between coronary artery calcification scores (CACs) and whole blood levels of trace elements.

METHODS

Patients undergoing HD in three times a week for > 6 months and age-and sex-matched controls were included from October 2015 to June 2016. Data were collected from patient files. All subjects' whole blood levels of trace elements were measured by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). CACs for patients were assessed by multi-detector computed tomography.

RESULTS

The 35 patients (male, 60%) with a mean age of 45.7 ± 10.4 years and 35 controls were included. HD patients showed significantly lower levels of selenium and uranium and higher cadmium (Cd), cobalt, lithium, manganese, nickel, lead, platinum, tin, strontium, and thallium levels compared to controls. Coronary artery calcification (CAC) was present in 21 patients (60%), and median CACs were 14.2 (IQR 0-149). Patients with CACs > median were significantly older, had a higher prevalence of hypertension and lower ALP levels than patients with CACs ≤ median. No significant differences in whole blood levels of trace elements were found between patients with CACs > median and patients with CACs ≤ median. A near significance was noted in median whole blood levels of Cd between these groups (P = 0.096). According to multivariate analysis, age was the only independent determinant for CAC development.

CONCLUSION

Age is independently associated with coronary vascular calcification. High Cd levels might play a role in CAC development in HD patients.

High relative amount of nodular calcification in femoral plaques is associated with milder lower extremity arterial disease

BACKGROUND

Clinical implications of different types of vascular calcification are poorly understood. The two most abundant forms of calcification, nodular and sheet calcification, have not been quantitatively analyzed in relation to the clinical presentation of lower extremity arterial disease (LEAD).

METHODS

The study analyzed 51 femoral artery plaques collected during femoral endarterectomy, characterized by the presence of > 90% stenosis. Comprehensive clinical data was obtained from patient records, including magnetic resonance angiography (MRA) images, toe pressure and ankle brachial index measurements and laboratory values. The plaques were longitudinally sectioned, stained with Hematoxylin and Eosin and digitized in a deep learning platform for quantification of the relative area of nodular and sheet calcification to the plaque section area. A deep learning artificial intelligence algorithm was designed and independently validated to reliably quantify nodular calcification and sheet calcification. Vessel measurements and quantity of each calcification category was compared to the risk factors and clinical presentation.

RESULTS

On average, > 90% stenosed vessels contained 22.4 ± 12.3% of nodular and 14.5 ± 11.8% of sheet calcification. Nodular calcification area proportion in lesions with > 90% stenosis is associated with reduced risk of critically low toe pressure (< 30 mmHg) (OR = 0.910, 95% CI = 0.835-0.992, p < 0.05), severely lowered ankle brachial index (< 0.4) (OR = 0.912, 95% CI = 0.84-0.986, p < 0.05), and semi-urgent operation (OR = 0.882, 95% CI = 0.797-0.976, p < 0.05). Sheet calcification did not show any significant association.

CONCLUSIONS

Large amount of nodular calcification is associated with less severe LEAD. Patients with nodular calcification may have better flow reserves despite local obstruction.

Dyslipidemia and coronary artery calcium: From association to development of a risk-prediction nomogram

BACKGROUND AND AIMS

The associations between dyslipidemia and coronary artery calcium (CAC) are controversial. We investigated their cross-sectional relationships and developed a predictive scoring system for prognostically significant coronary calcification (PSCC).

METHODS AND RESULTS

This study evaluated the lipid profiles and the CAC score (CACS) measured through multidetector computed tomography (MDCT) among Taiwanese adult patients in a tertiary hospital between 2011 and 2016. Patients with CACS higher than 100 were classified as having PSCC. Dyslipidemia for each lipid component was defined based on the clinical cutoffs or the use of the lipid-lowering agents. Multivariable logistic regression was used to assess the association between dyslipidemia and PSCC and the model performance was assessed using calibration plot, discrimination, and a decision curve analysis. Of the 3586 eligible patients, 364 (10.2%) had PSCC. Increased age, male sex, higher body mass index (BMI), and higher level of triglyceride (TG) were associated with PSCC. The adjusted odds ratios (95% confidence intervals) of PSCC was 1.15 (0.90-1.47) for dyslipidemia defined by total cholesterol (TC) ≥200 mg/dL, 1.06 (0.83-1.35) for low-density-lipoprotein-cholesterol (LDL-C) ≥130 mg/dL, and 1.36 (1.06-1.75) for TG ≥ 200 mg/dL. The positive association between TG ≥ 200 mg/dL and PSCC was not modified by sex. Incorporating hypertriglyceridemia did not significantly improve the predictive performance of the base model comprising of age, sex, BMI, smoking, hypertension, diabetes, estimated glomerular filtration rate, and fasting glucose.

CONCLUSIONS

Hypertriglyceridemia was significantly associated with the prevalent odds of PSCC. Our proposed predictive model may be a useful screening tool for PSCC.

An Overview of the Pathophysiology of Vascular Calcification in Chronic Kidney Disease

Abnormalities of calcium–phosphate balance, with subsequent bone metabolism disorders, are among the key and earliest features of chronic kidney disease (CKD). Recently, another consequence of these abnormalities was brought to light—namely, vascular calcification. Most studies performed in patients on dialysis suggest that their vascular calcification is more advanced than that seen in the general population. Furthermore, the progression of vessel wall mineralization is much more dynamic in patients with CKD.

Apart from the commonly assessed factors that promote vascular calcification, such as age, duration of dialysis, or poor control of calcium–phosphate status, several other factors have recently been identified. In the spectrum of substances involved in the regulation of the process of soft-tissue calcification, the most extensively studied in the nephrology literature are bone morphogenetic protein 7, osteoprotegerin, matrix Gla protein, fetuin-A, and the phosphatonins. Better understanding of the mechanisms underlying excess vascular mineralization have led to the development of promising new therapies.

Risk Factors Associated with Decreased Renal Function after Hand-Assisted Laparoscopic Donor Nephrectomy: A Multivariate Analysis of a Single Surgeon Experience

Background: Hand-assisted laparoscopic donor nephrectomy is a minimally invasive procedure for living kidney donation. The surgeon operative volume is associated with postoperative morbidity and mortality. We evaluated the risk factors associated with decreased renal function after hand-assisted laparoscopic donor nephrectomy performed by a single experienced surgeon. Methods: We included living renal donors who underwent hand-assisted laparoscopic donor nephrectomy by a single experienced surgeon between 2006 and 2013. Decreased renal function was defined as an estimated glomerular filtration rate (eGFR) of < 60 mL/min/1.73 m² on postoperative day 4. The donors were categorized into groups with postoperative eGFR < 60 mL/min/1.73 m² or ≥ 60 mL/min/1.73 m². Univariate and multivariate logistic regression analyses were performed to evaluate the risk factors associated with decreased renal function after hand-assisted laparoscopic donor nephrectomy. The hospital stay duration, intensive care unit admission rate, and eGFR at postoperative year 1 were evaluated. Results: Of 643 patients, 166 (25.8%) exhibited a postoperative eGFR of < 60 mL/min/1.73 m². Multivariate logistic regression analysis demonstrated that the risk factors for decreased renal function were age [odds ratio (95% confidence interval), 1.062 (1.035-1.089), P < 0.001], male sex [odds ratio (95% confidence interval), 3.436 (2.123-5.561), P < 0.001], body mass index (BMI) [odds ratio (95% confidence interval), 1.093 (1.016-1.177), P = 0.018], and preoperative eGFR [odds ratio (95% confidence interval), 0.902 (0.881-0.924), P < 0.001]. There were no significant differences in postoperative hospital stay duration and intensive care unit admission rate between the two groups. In addition, 383 of 643 donors were analyzed at postoperative year 1. Sixty donors consisting of 14 (5.0%) from the group of 279 donors in eGFR ≥ 60 mL/min/1.73 m², and 46 (44.2%) from the group of 104 donors in eGFR < 60 mL/min/1.73 m² had eGFR < 60 mL/min/1.73 m² at postoperative year 1 (P < 0.001). Conclusions: Increased age, male sex, higher BMI, and decreased preoperative eGFR were risk factors for decreased renal function after hand-assisted laparoscopic donor nephrectomy by a single experienced surgeon. These results provide important evidence for the safe perioperative management of living renal donors.

Clinical assessment of lipid profiles in live kidney donors

BACKGROUND

Abnormal serum lipid profiles are an issue in chronic kidney disease (CKD), but the clinical ramifications of dyslipidemia in live kidney donors are unclear. Thus, we explored the relationship between serum lipids and residual renal function in living donors post-nephrectomy.

METHODS

Charts of living donors who underwent nephrectomy between January 2010 and March 2013 were reviewed, targeting those with 6-month follow-up examinations at minimum. Altogether, 282 donors were studied, examining total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) levels assayed before donation by standard techniques. Median follow-up time was 14 months. The relationship between postoperative renal function and allograft biopsy results was assessed. Recursive partitioning was applied to identify optimal cut-off points for each parameter.

RESULTS

Median (interquartile range) serum TC, TG, LDL, and HDL levels were 183 (161-205) mg/dL, 86 (63-131) mg/dL, 108 (92-128) mg/dL, and 53 (44-62) mg/dL, respectively. The glomerular filtration rate at last follow-up was associated with TC (r = -0.187; P = .002) and LDL (r = -0.172; P = .005) levels, but showed no correlation with TG and HDL. Root nodes of TC and LDL determinations in recursive partitioning were 170.5 mg/dL and 80.5 mg/dL, respectively, serving as thresholds for further evaluation. On logistic regression analysis, the likelihood of CKD (glomerular filtration rate < 60 mL/min/1.73 m(2)) at last follow-up was greater in donors with elevated TC and LDL levels (odds ratio = 1.96 and 3.33; P = .021 and .029, respectively).

CONCLUSION

Kidney donors with serum TC and LDL elevations require close observation, given their demonstrable predisposition to CKD after donation.

Does Vascular Calcification Correlate with Pulse Wave Velocity in Hemodialysis Patients?

Vascular calcifications have been previously shown to be an independent predictor of mortality in dialysis patients and a similar association has been shown for arterial stiffness. Nonetheless, the relationship between vascular calcifications and pulse wave velocity (PWV) have so far been little explored. The goal of this study is to verify the correlation among vascular calcifications and rigidity of arterial wall in patients at dialysis start. Accordingly, we investigated the association between aortic PWV and coronary calcification measured by computed tomography (TC-score) in 105 adult incident hemodialysis patients. PWV resulted increased in patients with the higher TC-score values; indeed, at univariate analysis PWV directly correlated with age (p=0.016), presence of diabetes (p<0.0001), serum phosphorus (p=0.0066), C-reactive protein (CRP) (p=0.046), LDL-cholesterol (p=0.043), TC-score (p<0.0001), and inversely correlated with systolic blood pressure (p=0.036). At multivariate analysis, age, diabetes, serum phosphorus, CRP, LDL-cholesterol and vascular calcifications were determinants of arterial stiffening. Using the table “two for two”, we showed 6 false negative patients (high TC-score and low PWV) and 12 false positive patients (low TC-score and high PWV). The sensibility was 76% and the specificity 85%; the accuracy was 83%, the predictor positive value was 61% and the predictor negative value was 92%. Overall, a strong association between TC-score and PWV was seen.

Endothelial Lipase Activity Predicts High-Density Lipoprotein Catabolism in Hemodialysis

Objective—

A novel phospholipase assay was used to measure for the first time the behavior of endothelial and hepatic phospholipase activities in postheparin human plasma of hemodialyzed patients and its relationship with atherogenic and antiatherogenic lipoprotein levels.

Methods and Results—

Endothelial and hepatic phospholipase activity was assessed in a total SN1-specific phospholipase assay, using (1-decanoylthio-1-deoxy-2-decanoyl-sn-glycero-3-phosphoryl) ethylene glycol as the substrate. Hemodialyzed patients presented lower values of total and hepatic phospholipase activity than controls: 4.4 (1.9–9.0) versus 7.5 (3.6–18.0) and 2.6 (0.7–6.2) versus 6.6 (1.3–15.2) μmol of fatty acid released per milliliter of postheparin plasma per hour, respectively ( P <0.001); however, endothelial lipase (EL) phospholipase activity was increased in patients: 1.7 (0.8–3.0) versus 1.1 (0.1–2.7) μmol of fatty acid released per milliliter of postheparin plasma per hour ( P =0.008). EL was negatively associated with high-density lipoprotein (HDL)-cholesterol ( r =–0.427; P =0.001), and apolipoprotein A-I levels, total phospholipase, and hepatic lipase activity were directly associated with low-density lipoprotein-cholesterol and apolipoprotein B. The association of EL and HDL-cholesterol remained significant when adjusting for waist circumference (β=–0.26; P =0.05), and the effect of hepatic lipase on low-density lipoprotein-cholesterol continued after adjusting for age (β=0.46; P = 0.001).

Conclusion—

Our results support the hypothesis that EL is the predominant enzyme responsible for lipolytic catabolism of HDLs in hemodialyzed patients and resolve the apparent paradox observed between low hepatic lipase activity and decreased HDL-cholesterol levels observed in these patients. In addition, the ability to assess total hepatic lipase and EL phospholipase activity in plasma will increase our knowledge of the mechanisms involved in controlling HDL levels and cardiovascular risk in hemodialyzed patients, as well as other populations with low levels of HDL-cholesterol.

Phosphate metabolism in chronic kidney disease: from pathophysiology to clinical management

Hyperphosphatemia is considered as an independent risk factor for surrogate clinical endpoints like vascular calcification (VC) and bone disease, or hard clinical outcomes like cardiovascular events. To date, various treatment options for phosphate removal or reduction are available. The great expectations put into calcium-based phosphate binders were mitigated because of their possible contribution to progressive VC, particularly in patients treated simultaneously with active vitamin D derivatives. Thus, a paradigm change occurred whereby the main clinical concern shifted from the avoidance of hypocalcemia to that of the consequences of inducting a positive calcium balance. Sevelamer-HCl treatment allowed a comparable control of hyperphosphatemia with a lower risk of hypercalcemia than calcium-based phosphate binders, and a slower progression of VC; however, convincing evidence of improved clinical outcomes in dialysis patients is lacking. Although data on the safety and efficacy of lanthanum carbonate in the treatment of hyperphosphatemia have been provided in long-term clinical studies, there is still an ongoing scientific debate about its possible long-term toxicity. Moreover, there are no data from randomized clinical trials demonstrating beneficial effects of La carbonate treatment on VC or cardiovascular outcomes. In the absence of convincing clinical trials testing the effects of non-metal-based phosphate binders on cardiovascular and global outcomes it appears reasonable to maintain bone health and mineral homeostasis by mainly relying on adaptations of standard therapies. Noncalcium, non-aluminum-based binders might be reserved for patients with major mineral metabolism abnormalities and a high risk of VC.

Effect of MCI-196 on serum phosphate and cholesterol levels in haemodialysis patients with hyperphosphataemia: a double-blind, randomized, placebo-controlled study

BACKGROUND

Hyperphosphataemia in patients on haemodialysis (HD) can lead to, or worsen, secondary hyperparathyroidism (with associated bone disease) and extra-skeletal calcifications associated with increased cardiovascular morbidity and mortality. MCI-196 is a new, non-absorbed, non-calcium-based phosphate binder. The aim of this study was to determine the effect of three fixed doses of MCI-196, on serum phosphorus level and other parameters relevant to HD patients.

METHODS

A total of 120 chronic kidney disease (CKD) stage 5 patients on HD and with the serum phosphorus level >2.1 mmol/l were randomized to receive double-blind treatment with either 3, 6 and 9 g/day MCI-196 or placebo for 3 weeks.

RESULTS

Serum phosphorous decreased in all three treatment groups (-0.038, -0.268 and -0.257 mmol/l in the 3, 6 and 9 g/day groups, respectively). The difference between treatment and placebo groups was significant for the 6 and 9 g/day groups (P < 0.05 in both cases). Changes in the mean serum calcium were minimal and without relevant differences between groups. However, calcium-phosphorus product (Ca x P) was significantly reduced in the 6 and 9 g/day groups P < 0.05). MCI-196 at all doses decreased serum intact PTH between baseline and endpoint, and differences between treatment groups and placebo were statistically significant for the 3 and 9 g/day groups (P < 0.02 in both cases). Both serum total and LDL cholesterol decreased significantly in all treatment groups compared to placebo (by 0.71-1.05 mmol/l, for total cholesterol and 0.68-0.94 mmol/l for LDL cholesterol P < 0.001 in all cases). There was minimal change in serum HDL cholesterol. MCI-196 at all doses decreased significantly serum uric acid between baseline and endpoint compared to placebo (P < 0.005 in all cases). The drug was well tolerated.

CONCLUSION

MCI-196 significantly reduced serum phosphorus, Ca x P and PTH, without effecting serum calcium levels. The additional reduction in total cholesterol and LDL cholesterol indicates a possible dual mechanism of action of MCI-196 that has the potential to reduce cardiovascular morbidity in CKD stage 5 patients.

Association of serum alkaline phosphatase with coronary artery calcification in maintenance hemodialysis patients

BACKGROUND AND OBJECTIVES

Recent in vitro studies have shown a link between alkaline phosphatase and vascular calcification in patients with chronic kidney disease (CKD). High serum levels of alkaline phosphatase are associated with increased death risk in epidemiologic studies of maintenance hemodialysis (MHD) patients. We hypothesized that coronary artery calcification is independently associated with increased serum alkaline phosphatase levels in MHD patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We examined the association of coronary artery calcification score (CACS) and alkaline phosphatase in 137 randomly selected MHD patients for whom markers of malnutrition, inflammation, and bone and mineral disorders were also measured.

RESULTS

Serum alkaline phosphatase was the only measure with significant and robust association with CACS (P < 0.003), whereas either other biochemical markers had no association with CACS or their association was eliminated after controlling for case-mix variables. Serum alkaline phosphatase >120 IU/L was a robust predictor of higher CACS and was particularly associated with the likelihood of CACS >400 (multivariate odds ratio 5.0 95% confidence interval 1.6 to 16.3; P = 0.007). Serum alkaline phosphatase of approximately 85 IU/L seemed to be associated with the lowest likelihood of severe coronary artery calcification, but in the lowest tertile of alkaline phosphatase, the CACS predictability was not statistically significant.

CONCLUSIONS

An association between serum alkaline phosphatase level and CACS exists in MHD patients. Given the high burden of vascular calcification in patients with CKD, examining potential therapeutic interventions to modulate the alkaline phosphatase pathway may be warranted.

Cost-effectiveness of early versus late cinacalcet treatment in addition to standard care for secondary renal hyperparathyroidism in the USA

OBJECTIVES

The objective of this research was to estimate lifetime cost-effectiveness of treating patients with cinacalcet early (when parathyroid hormone [PTH] levels are in the range of 300-500 pg/ml) versus delaying treatment with cinacalcet (cinacalcet initiated when PTH levels are > 800 pg/ml) in patients with secondary hyperparathyroidism (SHPT) in the US setting.

METHODS

A Markov model was developed to simulate the effects of early versus delayed use of cinacalcet (plus standard of care). Four different PTH ranges (< or = 300 pg/ml; 301-500 pg/ml; 501-800 pg/ml; > 800 pg/ml) were used to represent four different health states within the Markov model. Associated with each Markov state (PTH range) were varying risks of major SHPT complications, including cardiovascular disease (CVD), fracture (Fx), and parathyroidectomy (PTx). Baseline cohort characteristics and risks of CVD, Fx, and PTx by PTH category were derived from a large US renal database and published sources. Costs were estimated from the US Renal Data System database and reported in 2006 US Dollars ($). Clinical and economic outcomes were discounted at 3.0% per annum.

RESULTS

Early treatment was projected to improve quality-adjusted life years (QALYs) by 0.337 years compared to delaying treatment. The incremental cost-effectiveness ratio was $17,275 per QALY gained.

CONCLUSIONS

Early treatment with cinacalcet was associated with improvements in QALYs and would represent good value for money compared to delaying treatment with cinacalcet.

Current Approaches in the Treatment of Chronic Kidney Disease Mineral and Bone Disorder

Patients with chronic kidney disease (CKD) develop mineral and bone disorder (MBD), a common and important complication, as a result of impaired phosphorus excretion and reduced vitamin D activation. Altered mineral metabolism is now recognized as an independent cardiovascular risk factor in end-stage renal disease patients and contributes to the risk for accelerating vascular calcification. CKD patients are at high risk for cardiovascular disease and vascular calcification which account for the high morbidity and mortality in this patient population. Pharmacotherapeutic interventions are necessary to manage and treat the condition. Multiple classes of agents including phosphorus binders, vitamin D analogs, and calcimimetics are now available to treat CKD-MBD. Recent data have shown that treatment with sevelamer and vitamin D analogs are associated with a reduction in calcification and cardiovascular mortality and improved survival. This article provides an overview of the strategies and considerations for the management of CKD-MBD, as well as their implications on clinical outcomes.

A 1-year randomized trial of calcium acetate versus sevelamer on progression of coronary artery calcification in hemodialysis patients with comparable lipid control: the Calcium Acetate Renagel Evaluation-2 (CARE-2) study

BACKGROUND

Previous clinical trials showed that progression of coronary artery calcification (CAC) may be slower in hemodialysis patients treated with sevelamer than those treated with calcium-based phosphate binders. Because sevelamer decreases low-density lipoprotein cholesterol (LDL-C) levels, we hypothesized that intensive lowering of LDL-C levels with atorvastatin in hemodialysis patients treated with calcium acetate would result in CAC progression rates similar to those in sevelamer-treated patients.

STUDY DESIGN

Randomized, controlled, open-label, noninferiority trial with an upper bound for the noninferiority margin of 1.8.

SETTING & PARTICIPANTS

203 prevalent hemodialysis patients at 26 dialysis centers with serum phosphorus levels greater than 5.5 mg/dL, LDL-C levels greater than 80 mg/dL, and baseline CAC scores of 30 to 7,000 units assessed by means of electron-beam computed tomography.

INTERVENTIONS

103 patients were randomly assigned to calcium acetate, and 100 patients to sevelamer for 12 months to achieve phosphorus levels of 3.5 to 5.5 mg/dL. Atorvastatin was added to achieve serum LDL-C levels less than 70 mg/dL in both groups.

OUTCOMES & MEASUREMENTS

The primary end point was change in CAC score assessed by means of electron-beam computed tomography.

RESULTS

After 12 months, mean serum LDL-C levels decreased to 68.8 +/- 22.0 mg/dL in the calcium-acetate group and 62.4 +/- 23.0 mg/dL in the sevelamer group (P = 0.3). Geometric mean increases in CAC scores were 35% in the calcium-acetate group and 39% in the sevelamer group, with a covariate-adjusted calcium acetate-sevelamer ratio of 0.994 (95% confidence interval, 0.851 to 1.161).

LIMITATIONS

Treatment assignment was not blinded. The 1.8 a priori margin is large, CAC is a surrogate outcome, duration of treatment was short, and dropout rate was high.

CONCLUSIONS

With intensive lowering of LDL-C levels for 1 year, hemodialysis patients treated with either calcium acetate or sevelamer experienced similar progression of CAC.

Bone health and vascular calcification relationships in chronic kidney disease

Abnormal bone in chronic kidney disease (CKD) may adversely affect vascular calcification via disordered calcium and phosphate metabolism. In this context, bone health should be viewed as a prerequisite for the successful prevention/treatment of vascular calcification (VC) along with controlled parathyroid hormone (PTH) secretion, the use of calcium-based phosphate binders and vitamin D therapy. In CKD patients, VC occurs more frequently and progresses more rapidly than in the general population, and is associated with increased cardiovascular disease (CVD) morbidity and mortality. A number of therapies aimed at reducing PTH concentration are associated with an increase of calcaemia and Ca x P product, e.g. calcium-containing phosphate binders or active vitamin D. The introduction of calcium-free phosphate binders has reduced calcium load, attenuating VC and improving trabecular bone content. In addition, a major breakthrough has been achieved through the use of calcimimetics, as first agents which lower PTH without increasing the concentrations of serum calcium and phosphate. Nowadays, it is becoming evident that even early stage CKD is recognised as an independent CVD risk factor. Moreover, the excess of CVD among dialysis patients cannot be explained entirely on the basis of abnormal mineral and bone metabolism. Hence, much controversy has surrounded the cost-effectiveness of treatment with the new phosphate-binding drugs as well as new vitamin D analogs and calcimimetics. Thus, it seems prudent and reasonable that maintaining bone health and mineral homeostasis should rely on some modifications of standard phosphate binding and calcitriol therapy. Hypophosphataemia and hypercalcaemia in adynamic bone disease (ABD) might be treated by reducing the number of calcium carbonate/acetate tablets in order to increase serum phosphate and decrease serum calcium, which, in turn, might positively stimulate PTH secretion. The same rationale is assumed for the use of a low calcium dialysate. On the other hand, secondary hyperparathyroidism with hyperphosphataemia and hypocalcaemia should be treated with a substantial number of calcium carbonate/acetate tablets in combination with calcitriol and low calcium dialysate in order to decrease serum phosphate and maintain the Ca x P product within K/DOQI guidelines (<4.4 mmol l(-1)). Finally, it becomes apparent that prevention, with judicious use of calcium-based binders, vitamin D and a low calcium dialysate without adverse effects on Ca x P or oversuppression of PTH, provides the best management of VC and mineral and bone disorder in CKD patients.

Mineral metabolism disturbances in patients with chronic kidney disease

BACKGROUND

Kidney disease, especially chronic kidney disease (CKD), is a worldwide public health problem with serious adverse health consequences for affected individuals. Secondary hyperparathyroidism, a disorder characterized by elevated serum parathyroid hormone levels, and alteration of calcium and phosphorus homeostasis are common metabolic complications of CKD that may impact cardiovascular health.

MATERIALS AND METHODS

Here, we systematically review published reports from recent observational studies and clinical trials that examine markers of altered mineral metabolism and clinical outcomes in patients with CKD.

RESULTS

Mineral metabolism disturbances begin early during the course of chronic kidney disease, and are associated with cardiovascular disease and mortality in observational studies. Vascular calcification is one plausible mechanism connecting renal-related mineral metabolism with cardiovascular risk. Individual therapies to correct mineral metabolism disturbances have been associated with clinical benefit in some observational studies; clinical trials directed at more comprehensive control of this problem are warranted.

CONCLUSIONS

There exists a potential to improve outcomes for patients with CKD through increased awareness of the Bone Metabolism and Disease guidelines set forth by the National Kidney Foundation-Kidney Disease Outcomes Quality Initiative. Future studies may include more aggressive therapy with a combination of agents that address vitamin D deficiency, parathyroid hormone and phosphorus excess, as well as novel agents that modulate circulating promoters and inhibitors of calcification.

Donor factors influencing graft outcomes in live donor kidney transplantation

Living donor renal allograft survival is superior to that achieved from deceased donors, although graft outcome is suboptimal in some of these patients. In an effort to identify the subset of patients at high risk for poor outcomes we studied donor risk factors in 248 living kidney donor-recipient pairs. Unadjusted donor (125)I-iothalamate GFR (iGFR), donor age more than 45 years, donor total cholesterol level less than 200 mg/dL, and donor systolic blood pressure (SBP) less than 120 mm Hg were correlated with allograft estimated glomerular filtration rate (eGFR), and incidence of acute rejection (AR), delayed graft function and/or graft loss at 2 years posttransplantation. Donor iGFR less than 110 mL/min (slope=-7.40, P<0.01), donors more than 45 years (slope=-8.76, P<0.01), donor total cholesterol levels more than 200 mg/dL (slope=-10.03, P<0.01), and SBP more than 120 mm Hg (slope=-5.60, P=0.03) were associated with lower eGFR. By multivariable linear regression analysis these variables remained independently associated with lower eGFR, and poorer outcomes. The increasing number of donor factors (age, iGFR, cholesterol, and blood pressure) was directly associated with worse posttransplant eGFR (P<0.01). In conclusion, our data suggest that routine assessment of living donor parameters could supplement the consideration of recipient characteristics in predicting posttransplant risk of graft injury/dysfunction.

Cardiac Vascular Calcification and QT Interval in ESRD Patients: Is There a Link?

We will present our experience and our preliminary data about the correlation between cardiac calcification and QT interval (and QT dispersion) in uraemia. We studied 32 haemodialysis (HD) patients (age 69 +/- 16 years, time on dialysis 32 +/- 27 months) and 12 chronic kidney disease stage 4 (CKD-4) patients (age 66 +/- 17 years, uraemia duration 38 +/- 16 months). The patients were characterized by a good mineral control, as shown by serum phosphate levels (3.6 +/- 1.3 mg/dl in CKD-4 and 4.3 +/- 1.6 mg/dl in HD patients) and Ca x P product (46 +/- 17 and 49 +/- 16 mg(2)/dl(2), respectively). The parathyroid hormone levels were higher in HD than CKD-4 patients (p < 0.0001). A TC score >400 was found to be highly prevalent in both groups. Significantly more HD patients (62.5%) showed cardiac calcification than CKD-4 patients (33%; p = 0.01). The patients were matched for TC scores higher or lower than 400. The two groups differed by gender (p < 0.05), age (p = 0.026), frequency of diabetes mellitus (p < 0.01), uraemia follow-up period (p < 0.001), low-density lipoprotein cholesterol level (p = 0.009), Ca x P product (p = 0.002), parathyroid hormone level (p < 0.0001), and corrected QT dispersion (p < 0.0001). The QT interval was higher in HD and CKD-4 patients with higher TC scores (approximately 11%), but QT interval dispersion was significantly higher in patients with TC scores >400. QT dispersion showed a linear correlation with TC scores in both groups (r = 0.899 and p < 0.0001 and r = 0.901 and p < 0.0001). Male gender, age, time (months) of uraemia, low-density lipoprotein cholesterol, albumin, calcium x phosphorus product, parathyroid hormone, and TC score are important determinants of QT dispersion. Our data show that it is possible to link dysrhythmias and cardiac calcification in uraemic patients.

Atherosclerotic risk factors and carotid stiffness in elderly asymptomatic HD patients

Several studies showed that carotid atherosclerosis and stiffness are independent prognostic factors of cardiovascular morbidity and mortality in the general population and in end-stage renal disease patients. However, the impact of established risk factors on carotid structural and elastic properties in non-diabetic elderly hemodialysis patients with negative history for cardiovascular disease has not been fully elucidated. In this paper, we investigated the effect of established and potential risk factors on carotid atherosclerosis and stiffness. Thirty stable, non-symptomatic, non-diabetic patients, aged 65-years and older (mean age 71.4+/-4.15, range 65-79) on hemodialysis for more than 6 months, were included. All patients underwent B-mode ultrasonography of common carotid artery estimating intima-media wall thickness and wall-to-lumen ratio bilaterally and checking for the presence of plaques. Carotid elasticity was evaluated by compliance, distensibility, and the incremental elastic modulus (Einc), whereas systemic arterial stiffening was evaluated by the augmentation index provided by tonometry of radial artery. Our results showed that presence of carotid plaques and wall thickening were frequent findings in this population (76% and 73.3%, respectively) and they were positively associated with fibrinogen (P<0.005), diastolic blood pressure (P<0.004), visceral obesity (P<0.001) and bio-intact PTH (i-PTH) (P=0.03). Overall, systemic and carotid stiffness were strongly correlated with hs-CRP (P=0.018), serum ferritin (P=0.02) with age (P=0.03), lipids (P=0.03) and i-PTH (P=0.05). In conclusion, our findings show that stiffening and atherosclerosis in non-symptomatic elderly HD patients are very common and they are related not only to hemodynamic changes (diastolic blood pressure), inflammation (hs-CRP, fibrinogen, ferritin) or metabolic dysfunction (increased i-PTH, abnormal lipid profile), but also to abnormal fat deposition (increased waist to hip ratio and waist circumference). Considering the high morbidity and mortality of elderly patients, close monitoring of these parameters could be useful to prevent cardiovascular events.

Endocrinology and Dialysis: Management of Lipid Abnormalities Associated with End-Stage Renal Disease

The management of lipid abnormalities in patients with end-stage renal disease (ESRD) remains controversial. Large, well-designed studies investigating the effects of dyslipidemia on cardiovascular (CV) morbidity and mortality and the role of cholesterol lowering drugs in reducing mortality in ESRD patients are lacking. While it seems reasonable to suspect that dyslipidemia and its treatment in ESRD patients will affect CV morbidity and mortality similar to that in the general population, recent studies have suggested that this may not be the case. Furthermore, the pharmacokinetics of lipid lowering drugs are altered in patients with ESRD and must be considered when treating this group of patients. This article reviews the major classes of drugs used to treat dyslipidemia, emphasizing their role in patients with ESRD.

The safety of phosphate binders

Disturbances of mineral metabolism occur during the early stages of chronic kidney disease. As renal function worsens, excess dietary phosphorus accumulates and blood levels increase, that can be clearly seen when the glomerular filtration rate has fallen below 30 ml/min/1.73 m2. In patients with end stage renal disease, standard dialysis (three times/week) falls far short of removing adequate amounts of absorbed phosphorus; therefore, hyperphosphataemia is found in the majority of these patients. Hyperphosphataemia has long been associated with progression of secondary hyperparathyroidism and renal osteodystrophy, it can also lead to soft-tissue and vascular calcification. Recent observational data have associated hyperphosphataemia with increased cardiovascular mortality among dialysis patients. Adequate control of serum phosphorus remains a cornerstone in the clinical management and, despite the growing amount of available therapeutic options, achievement of NFK/KDOQI targets for mineral metabolism remain poor. Several reasons may explain the failure to adequately treat hyperphosphataemia: poor compliance with diet and phosphate binder prescriptions are common causes. Also, factors related with cost, tolerance, palatability, safety and efficacy are important. In this article, the authors review the advantages and drawbacks of conventional and emerging therapies in phosphorous binding.

Reappraisal of 2003 NKF-K/DOQI guidelines for management of hyperparathyroidism in chronic kidney disease patients

The 2003 guidelines for the management of hyperparathyroidism in chronic kidney disease compiled by the Kidney Disease Outcomes Quality Initiative of the National Kidney Foundation (NKF-K/DOQI) were formulated on the basis of work published up until 2001. Since then, new drugs (e.g. calcimimetics and lanthanum carbonate) have become available, and others (e.g. sevelamer, nicotinamide and paricalcitol) have been more stringently clinically evaluated. Because of these advancements, a reappraisal of the 2003 guidelines is justified. In this article we critically review the following recommendations of the NKF-K/DOQI: (i) routine use of 1.25 mmol/l (5.0 mg/dl) dialysate calcium and 1 alphaOH-vitamin D derivatives; (ii) limitation of the maximal daily dose of calcium-based oral phosphate binders to 1.5 g of elemental calcium; and (iii) not correcting vitamin D insufficiency in dialysis patients.

Calcium-Based Phosphate Binders Are Appropriate in Chronic Renal Failure

Many nephrologists feel threatened by the allegation that, in patients with chronic renal failure, treatment with calcium-based phosphate binders (calcium acetate and calcium carbonate) may induce coronary artery and cardiac calcification, thereby imposing a greater risk for death compared with sevelamer, a non-calcium-based binder. Acknowledging that drug manufacturers are not unaware of the marketing advantage to their product consequent to destabilizing demand for competing drugs, the case for and against abandoning calcium-based phosphate binders in favor of sevelamer is reviewed in this study. The case for continuing prescription of calcium-based phosphate binders stands on the following: (1) flawed clinical trials that favor sevelamer as a replacement; (2) weak evidence that oral calcium intake modulates vascular and/or cardiac calcification; (3) clinical trials that reinforce the safety and efficacy of calcium-based phosphate binders; and (4) the inordinate relative cost of sevelamer. Recognizing that established as well as novel phosphate binders are currently undergoing clinical evaluation, an open mind and an awareness of developing literature are necessary when deciding how to manage hyperphosphatemia in renal failure.