Sudden cardiac death in CKD patients

Atorvastatin, etanercept and the nephrogenic cardiac sympathetic remodeling in chronic renal failure rats

BACKGROUND

Chronic renal failure (CRF) patients are predisposed to arrhythmias, while the detailed mechanisms are unclear. We hypothesized the chronic inflammatory state of CRF patients may lead to cardiac sympathetic remodeling, increasing the incidence of ventricular arrhythmia (VA) and sudden cardiac death. And explored the role of atorvastatin and etanercept in this process.

METHODS

A total of 48 rats were randomly divided into sham operation group (Sham group), CRF group, CRF + atorvastatin group (CRF + statin group), and CRF + etanercept group (CRF + rhTNFR-Fc group). Sympathetic nerve remodeling was assessed by immunofluorescence of growth-associated protein 43 (GAP-43) and tyrosine hydroxylase positive area fraction. Electrophysiological testing was performed to assess the incidence of VA by assessing the ventricular effective refractory period and ventricular fibrillation threshold. The levels of tumor necrosis factor-alpha (TNF-α) and interleukin-1beta were determined by Western blotting and enzyme-linked immunosorbent assay.

RESULTS

Echocardiogram showed that compared with the Sham group, left ventricular end-systolic diameter and ventricular weight/body weight ratio were significantly higher in the CRF group. Hematoxylin-eosin and Masson staining indicated that myocardial fibers were broken, disordered, and fibrotic in the CRF group. Western blotting, enzyme-linked immunosorbent assay, immunofluorescence and electrophysiological examination suggested that compared with the Sham group, GAP-43 and TNF-α proteins were significantly upregulated, GAP-43 and tyrosine hydroxylase positive nerve fiber area was increased, and ventricular fibrillation threshold was significantly decreased in the CRF group. The above effects were inhibited in the CRF + statin group and the CRF + rhTNFR-Fc group.

CONCLUSIONS

In CRF rats, TNF-α was upregulated, cardiac sympathetic remodeling was more severe, and the nephrogenic cardiac sympathetic remodeling existed. Atorvastatin and etanercept could downregulate the expression of TNF-α or inhibit its activity, thus inhibited the above effects, and reduced the occurrence of VA and sudden cardiac death.

Impact of Impaired Kidney Function on Arrhythmia-Promoting Cardiac Ion Channel Regulation

Chronic kidney disease (CKD) is associated with a significantly increased risk of cardiovascular events and sudden cardiac death. Although arrhythmias are one of the most common causes of sudden cardiac death in CKD patients, the molecular mechanisms involved in the development of arrhythmias are still poorly understood. In this narrative review, therefore, we summarize the current knowledge on the regulation of cardiac ion channels that contribute to arrhythmia in CKD. We do this by first explaining the excitation-contraction coupling, outlining current translational research approaches, then explaining the main characteristics in CKD patients, such as abnormalities in electrolytes and pH, activation of the autonomic nervous system, and the renin-angiotensin-aldosterone system, as well as current evidence for proarrhythmic properties of uremic toxins. Finally, we discuss the substance class of sodium-glucose co-transporter 2 inhibitors (SGLT2i) on their potential to modify cardiac channel regulation in CKD and, therefore, as a treatment option for arrhythmias.

Pro-Arrhythmic Potential of Accumulated Uremic Toxins Is Mediated via Vulnerability of Action Potential Repolarization

Chronic kidney disease (CKD) is represented by a diminished filtration capacity of the kidneys. End-stage renal disease patients need dialysis treatment to remove waste and toxins from the circulation. However, endogenously produced uremic toxins (UTs) cannot always be filtered during dialysis. UTs are among the CKD-related factors that have been linked to maladaptive and pathophysiological remodeling of the heart. Importantly, 50% of the deaths in dialysis patients are cardiovascular related, with sudden cardiac death predominating. However, the mechanisms responsible remain poorly understood. The current study aimed to assess the vulnerability of action potential repolarization caused by exposure to pre-identified UTs at clinically relevant concentrations. We exposed human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and HEK293 chronically (48 h) to the UTs indoxyl sulfate, kynurenine, or kynurenic acid. We used optical and manual electrophysiological techniques to assess action potential duration (APD) in the hiPSC-CMs and recorded IKr currents in stably transfected HEK293 cells (HEK-hERG). Molecular analysis of KV11.1, the ion channel responsible for IKr, was performed to further understand the potential mechanism underlying the effects of the UTs. Chronic exposure to the UTs resulted in significant APD prolongation. Subsequent assessment of the repolarization current IKr, often most sensitive and responsible for APD alterations, showed decreased current densities after chronic exposure to the UTs. This outcome was supported by lowered protein levels of KV11.1. Finally, treatment with an activator of the IKr current, LUF7244, could reverse the APD prolongation, indicating the potential modulation of electrophysiological effects caused by these UTs. This study highlights the pro-arrhythmogenic potential of UTs and reveals a mode of action by which they affect cardiac repolarization.

Effect of Implanted Defibrillator on Mortality in Patients With Chronic Kidney Disease

The beneficial role of implantable cardioverter defibrillators (ICDs) in patients with chronic kidney disease (CKD) is controversial. This meta-analysis aimed to evaluate the effect of ICD on mortality in patients with CKD. A literature search was conducted for studies reporting the effect of ICD on all-cause mortality in patients with CKD (estimated glomerular filtration rate <60 ml/min/1.73 m²). The search was not restricted to time or publication status. The search included the following databases: Ovid MEDLINE, EMBASE, Scopus, Web of Science, Google Scholar, and EBSCO CINAHL. The primary end point was all-cause mortality. The minimum duration of follow-up required for inclusion was 1 year. The literature search identified 834 studies, of which 14 studies with 70,661 patients were included. Mean follow-up was 39 months (12 to 81 months). For all patients with CKD, ICD was associated with lower all-cause mortality (log hazard ratio [HR] -0.247, standard error [SE] 0.101, p = 0.015). Heterogeneity: degree of freedom = 13 (p <0.01), I² = 97.057; test for overall effect: Z = -2.431 (p = 0.015). When further stratified based on dialysis, patients with CKD without the need for dialysis had significantly lower mortality (log HR -0.211, SE 0.095, p = 0.026), with a similar trend in patients who underwent dialysis (log HR -0.262, SE 0.134, p = 0.051). ICD implantation is associated with a significant mortality benefit in patients with CKD.

Uremic toxins in chronic kidney disease highlight a fundamental gap in understanding their detrimental effects on cardiac electrophysiology and arrhythmogenesis

Chronic kidney disease (CKD) and cardiovascular disease (CVD) have an estimated 700-800 and 523 million cases worldwide, respectively, with CVD being the leading cause of death in CKD patients. The pathophysiological interplay between the heart and kidneys is defined as the cardiorenal syndrome (CRS), in which worsening of kidney function is represented by increased plasma concentrations of uremic toxins (UTs), culminating in dialysis patients. As there is a high incidence of CVD in CKD patients, accompanied by arrhythmias and sudden cardiac death, knowledge on electrophysiological remodeling would be instrumental for understanding the CRS. While the interplay between both organs is clearly of importance in CRS, the involvement of UTs in pro-arrhythmic remodeling is only poorly investigated, especially regarding the mechanistic background. Currently, the clinical approach against potential arrhythmic events is mainly restricted to symptom treatment, stressing the need for fundamental research on UT in relation to electrophysiology. This review addresses the existing knowledge of UTs and cardiac electrophysiology, and the experimental research gap between fundamental research and clinical research of the CRS. Clinically, mainly absorbents like ibuprofen and AST-120 are studied, which show limited safe and efficient usability. Experimental research shows disturbances in cardiac electrical activation and conduction after inducing CKD or exposure to UTs, but are scarcely present or focus solely on already well-investigated UTs. Based on UTs data derived from CKD patient cohort studies, a clinically relevant overview of physiological and pathological UTs concentrations is created. Using this, future experimental research is stimulated to involve electrophysiologically translatable animals, such as rabbits, or in vitro engineered heart tissues.

Prognostic Effect of Underlying Chronic Kidney Disease and Renal Replacement Therapy on the Outcome of Patients after Out-of-Hospital Cardiac Arrest: A Nationwide Observational Study

Background and Objectives: This study assessed the prognostic value of underlying chronic kidney disease (CKD) and renal replacement therapy (RRT) on the clinical outcomes from out-of-hospital cardiac arrest (OHCA). Materials and Methods: This retrospective study was conducted utilizing the population-based OHCA data of South Korea between 2008 and 2018. Adult (>18 years) OHCA patients with a medical cause of cardiac arrest were included and classified into three categories based on the underlying CKD and RRT: (1) non-CKD group; (2) CKD without RRT group; and (3) CKD with RRT group. A total of 13,682 eligible patients were included (non-CKD, 9863; CKD without RRT, 1778; CKD with RRT, 2041). From the three comparison subgroups, data with propensity score matching were extracted. The influence of CKD and RRT on patient outcomes was assessed using propensity score matching and multivariate logistic regression analyses. The primary outcome was survival at hospital discharge and the secondary outcome was a good neurological outcome at hospital discharge. Results: The two CKD groups (CKD without RRT and CKD with RRT) showed no significant difference in survival at hospital discharge compared with the non-CKD group (CKD without RRT vs. non-CKD, p > 0.05; CKD with RRT vs. non-CKD, p > 0.05). The non-CKD group had a higher chance of having good neurological outcomes than the CKD groups (non-CKD vs. CKD without RRT, p < 0.05; non-CKD vs. CKD with RRT, p < 0.05) whereas there was no significant difference between the two CKD groups (CKD without RRT vs. CKD with RRT, p > 0.05). Conclusions: Compared with patients without CKD, the underlying cause of CKD—regardless of RRT—may be linked to poor neurological outcomes. Underlying CKD and RRT had no effect on the survival at hospital discharge.

Naringin and Trimetazidine Improve Baroreflex Sensitivity and Nucleus Tractus Solitarius Electrical Activity in Renal Ischemia-Reperfusion Injury

BACKGROUND

Nucleus tractus solitarius (NTS) is a brain area that plays a key role in kidney and cardiovascular regulation via baroreceptors impulses.

OBJECTIVES

The aim of this study was to evaluate the effect of naringin (NAR) and trimetazidine (TMZ) alone and their combination on NTS electrical activity and baroreceptor sensitivity (BRS) in renal ischemia- reperfusion (I/R) injury.

METHODS

Forty male Sprague-Dawley rats (200- 250 g) were allocated into 5 groups with 8 in each. 1) Sham; 2) I/R; 3) TMZ 5 mg/kg; 4) NAR 100 mg/kg; and 5) TMZ5+ NAR100. The left femoral vein was cannulated to infuse saline solution or drug and the BRS was evaluated. I/R was induced by occlusion of renal pedicles for 45 min, followed by 4 hours of reperfusion. The NTS local electroencephalogram (EEG) was recorded before, during ischemia and throughout the reperfusion. Phenylephrine was injected intravenously to evaluate BRS at the end of reperfusion time. The data were analyzed by two-way repeated measurement ANOVA followed by Tukey's post hoc test. A p-value <0.05 was considered significant.

RESULTS

NTS electrical waves did not change during ischemia time, while they significantly decreased during the entire reperfusion time. NTS electrical activity and BRS dramatically reduced in rats with I/R injury; however, administration of NAR, TMZ alone or their combination significantly improved these changes in rats with I/R injury.

CONCLUSIONS

The results showed that I/R injury leads to reduced BRS and NTS electrical activity and there may be an association between I/R and decreased BRS. In addition, NAR and TMZ are promising agents to treat I/R complications.

Association between wide QRS pulseless electrical activity and hyperkalemia in cardiac arrest patients

AIM

We evaluated the relationship between hyperkalemia and wide QRS complex in patients with pulseless electrical activity (PEA) cardiac arrest.

METHODS

This was a single-center, retrospective observational study of patients over the age of 18 treated for cardiac arrest at a tertiary referral hospital whose initial electrocardiogram rhythm was PEA from February 2010 to December 2019. Wide QRS PEA was defined as a QRS interval of 120 ms or more. Hyperkalemia was defined as serum potassium level > 5.5 mmol/L. The primary outcome was hyperkalemia. Multivariable logistic regression analysis was used to evaluate the relationship between wide QRS and hyperkalemia.

RESULTS

Among 617 patients, we analyzed 111 episodes in the wide QRS group and 506 episodes in the narrow QRS group. The potassium level in the wide QRS group was significantly higher than in the narrow QRS group (5.4 mmol/L, IQR 4.4-6.7 vs. 4.6 mmol/L, IQR 4.0-5.6, P < 0.001). Among all patients, 49.6% (n = 55/111) in the wide QRS group had hyperkalemia, which was significantly higher than the 26.7% (n = 135/506) in the narrow QRS group (P < 0.001). In multivariable logistic regression analysis, wide QRS PEA was significantly associated with hyperkalemia (odds ratio = 2.86, 95% confidence interval: 1.80-4.53, P < 0.001).

CONCLUSIONS

Wide QRS PEA as an initial cardiac rhythm was significantly associated with hyperkalemia in cardiac arrest patients.

Evaluation of inflammatory and cardiac-electrophysiological markers in patients undergoing peritoneal dialysis

Background: The Tp-e/QT (peak to end of T-wave duration/QT interval) ratio is a promising marker of myocardial repolarization and ventricular arrhythmogenesis. Its elevation is associated with sudden cardiac death in different clinical conditions. This study was designed to assess the possible association between increased Tp-e/QT ratio and clinical factors in peritoneal dialysis patients. Materials & methods: We devised a prospective cross-sectional study, which included 107 patients who were divided into groups according to their Tp-e/QT ratio. The association of an increased Tp-e/QT ratio with related factors was analyzed with multivariate logistic regression. Results: Thirty-one patients, who had an elevated Tp-e/QT ratio, showed higher values of IL-6, left ventricular end-systolic diameter, Tp-e, percentage of diabetes mellitus, coronary artery calcification, and left ventricular ejection fraction. Multivariate analysis revealed that IL-6 was an independent risk factor for a higher Tp-e/QT ratio after adjustments. Conclusion: Our study revealed that a high serum IL-6 level in peritoneal dialysis patients increased the risk of a higher Tp-e/QT ratio, which indicated a potentially hazardous interplay between inflammation and arrhythmogenesis.

Out-of-hospital cardiac arrest in dialysis patients

Purpose

The aim of the study was to assess whether a history of dialysis is related to cardiopulmonary resuscitation (CPR) attempts and survival to hospital admission in patients with out-of-hospital cardiac arrest (OHCA).

Methods

The databases of the POL-OHCA registry and of emergency medical calls in the Command Support System of the State of Emergency Medicine (CSS) were searched to identify patients with OHCA and a history of dialysis. A total of 264 dialysis patient with OHCA were found: 126 were dead on arrival of emergency medical services (EMS), and 138 had OHCA with CPR attempts. Data from the POL-OHCA registry for patients with CPR attempts, including age, sex, place of residence, first recorded rhythm, defibrillation during CPR, and priority dispatch codes, were collected and compared between patients with and without dialysis.

Results

CPR attempts by EMS were undertaken in 138 dialyzed patients (52.3%). The analysis of POL-OHCA data revealed no differences in age, sex, place of residence, first recorded rhythm, and priority dispatch codes between patients with and without dialysis. Defibrillation was less frequent in dialysis patients (P = 0.04). A stepwise logistic regression analysis revealed no association between survival to hospital admission and a history of hemodialysis (odds ratio = 1.12; 95% CI 0.74–1.70, P = 0.60).

Conclusions

A history of dialysis in patients with OHCA does not affect the rate of CPR attempts by EMS or a short-term outcome in comparison with patients without dialysis. Defibrillation during CPR is less common in patients on dialysis than in those without.

Sudden death in heart failure with preserved ejection fraction and beyond: an elusive target

Heart failure (HF) with preserved ejection fraction (HFpEF) represents half of HF patients, who are more likely older, women, and hypertensive. Mortality rates in HFpEF are higher compared with age- and comorbidity-matched non-HF controls and lower than in HF with reduced ejection fraction (HFrEF); the majority (50-70%) are cardiovascular (CV) deaths. Among CV deaths, sudden death (SD) (~ 35%) and HF-death (~ 20%) are the leading cardiac modes of death; however, proportionally, CV deaths, SD, and HF-deaths are lower in HFpEF, while non-CV deaths constitute a higher proportion of deaths in HFpEF (30-40%) than in HFrEF (~ 15%). Importantly, the underlying mechanism of SD has not been clearly elucidated and non-arrhythmic SD may be more prominent in HFpEF than in HFrEF. Furthermore, there is no specific strategy for identifying high-risk patients, probably due to wide heterogeneity in presentation and pathophysiology of HFpEF and a plethora of comorbidities in this population. Thus, the management of HFpEF remains problematic due to paucity of data on the clinical benefits of current therapies, which focus on symptom relief and reduction of HF-hospitalization by controlling fluid retention and managing risk-factors and comorbidities. Matching a specific pathophysiology or mode of death with available and novel therapies may improve outcomes in HFpEF. However, this still remains an elusive target, as we need more information on determinants of SD. Implantable cardioverter-defibrillators (ICDs) have changed the landscape of SD prevention in HFrEF; if ICDs are to be applied to HFpEF, there must be a coordinated effort to identify and select high-risk patients.

Melatonin receptor activation protects against low potassium-induced ventricular fibrillation by preserving action potentials and connexin-43 topology in isolated rat hearts

Hypokalemia prolongs the QRS and QT intervals, deteriorates intercellular coupling, and increases the risk for arrhythmia. Melatonin preserves gap junctions and shortens action potential as potential antiarrhythmic mechanisms, but its properties under hypokalemia remain unknown. We hypothesized that melatonin protects against low potassium-induced arrhythmias through the activation of its receptors, resulting in action potential shortening and connexin-43 preservation. After stabilization in Krebs-Henseleit solution (4.5 mEq/L K⁺ ), isolated hearts from Wistar rats underwent perfusion with low-potassium (1 mEq/L) solution and melatonin (100 μmol/L), a melatonin receptor blocker (luzindole, 5 μmol/L), melatonin + luzindole or vehicle. The primary endpoint of the study was the prevention of ventricular fibrillation. Electrocardiography was used, and epicardial action potentials and heart function were measured and analyzed. The ventricular expression, dephosphorylation, and distribution of connexin-43 were examined. Melatonin reduced the incidence of low potassium-induced ventricular fibrillation from 100% to 59%, delayed the occurrence of ventricular fibrillation and induced a faster recovery of sinus rhythm during potassium restitution. Melatonin prevented QRS widening, action potential activation delay, and the prolongation of action potential duration at 50% of repolarization. Other ECG and action potential parameters, the left ventricular developed pressure, and nonsustained ventricular arrhythmias did not differ among groups. Melatonin prevented connexin-43 dephosphorylation and its abnormal topology (lateralization). Luzindole abrogated the protective effects of melatonin on electrophysiological properties and connexin-43 misdistribution. Our results indicate that melatonin receptor activation protects against low potassium-induced ventricular fibrillation, shortens action potential duration, preserves ventricular electrical activation, and prevents acute changes in connexin-43 distribution. All of these properties make melatonin a remarkable antifibrillatory agent.

Antiarrhythmic effect linked to melatonin cardiorenal protection involves AT1 reduction and Hsp70-VDR increase

Lethal ventricular arrhythmias increase in patients with chronic kidney disease that suffer an acute coronary event. Chronic kidney disease induces myocardial remodeling, oxidative stress, and arrhythmogenesis. A manifestation of the relationship between kidney and heart is the concomitant reduction in vitamin D receptor (VDR) and the increase in angiotensin II receptor type 1 (AT₁ ). Melatonin has renal and cardiac protective actions. One potential mechanism is the increase in the heat shock protein 70 (Hsp70)-an antioxidant factor. We aim to determine the mechanisms involved in melatonin (Mel) prevention of kidney damage and arrhythmogenic heart remodeling. Unilateral ureteral-obstruction (UUO) and sham-operated rats were treated with either melatonin (4 mg/kg/day) or vehicle for 15 days. Hearts and kidneys from obstructed rats showed a reduction in VDR and Hsp70. Associated with AT₁ up-regulation in the kidneys and the heart of UUO rats also increased oxidative stress, fibrosis, apoptosis, mitochondrial edema, and dilated crests. Melatonin prevented these changes and ventricular fibrillation during reperfusion. The action potential lengthened and hyperpolarized in melatonin-treated rats throughout the experiment. We conclude that melatonin prevents renal damage and arrhythmogenic myocardial remodeling during unilateral ureteral obstruction due to a decrease in oxidative stress/fibrosis/apoptosis associated with AT₁ reduction and Hsp70-VDR increase.

Estimated Glomerular Filtration Rate, Proteinuria, and Risk of Cardiovascular Diseases and All-cause Mortality in Diabetic Population: a Community-based Cohort Study

Data about associations between estimated glomerular filtration rate (eGFR) and proteinuria with cardiovascular diseases (CVDs) and all-cause mortality among diabetic population is less described. We aimed to describe these associations in Chinese diabetic population, and investigate the difference between sexes. The study was based on 8,301 diabetic participants in the Kailuan study, who was free of CVDs at baseline. We used Cox proportional hazard models to examine the associations of eGFR and proteinuria with CVDs and all-cause mortality. A stratified analysis by gender was performed. During a median follow-up of 8.05 years, 917 deaths and 813 incident CVDs occurred. Adjusted for all potential confounders, eGFR was associated with all-cause mortality, but not associated with incidence of CVDs. Compared to those with eGFR ≥ 90 ml/min/1.73 m², Participants with eGFR <45 ml/min/1.73 m² had 1.50 fold higher risk of all-cause mortality. Adjusted for all potential confounders, proteinuria was associated with risk of both CVDs and all-cause mortality. Additionally, the risk of all-cause mortality by proteinuria was greater in women than that in men. Both lower eGFR and proteinuria are independent risk factors for all-cause mortality in the Chinese diabetic population. Proteinuria conferred excessive risk for CVDs, and especially in women.

Telomere attrition, kidney function, and prevalent chronic kidney disease in the United States

Background

Telomere length is an emerging novel biomarker of biologic age, cardiovascular risk and chronic medical conditions. Few studies have focused on the association between telomere length (TL) and kidney function.

Objective

We investigated the association between TL and kidney function/prevalent chronic kidney disease (CKD) in US adults.

Methods

The National Health and Nutrition Examination Survey (NHANES) participants with measured data on kidney function and TL from 1999 to 2002 were included. Estimated glomerular filtration rate (eGFR) was based on CKD Epidemiology Collaboration (CKD-EPI) equation. Urinary albumin excretion was assessed using urinary albumin-creatinine ratio (ACR). We used multivariable adjusted linear and logistic regression models, accounting for the survey design and sample weights.

Results

Of the 10568 eligible participants, 48.0% (n=5020) were men. Their mean age was 44.1 years. eGFR significantly decreased and ACR significantly increased across increasing quarters of TL (all p<0.001). The association between TL and kidney function remained robust even after adjusting for potential confounding factors, but the association between TL and ACR was only borderline significant (β-coefficient= -0.012, p=0.056).

Conclusion

The association of kidney function with a marker of cellular senescence suggests an underlying mechanism influencing the progression of nephropathy.

Clinical SYNTAX Score - a good predictor for renal artery stenosis in acute myocardial infarction patients: analysis from the REN-ACS trial

INTRODUCTION

In ST-elevation myocardial infarction (STEMI) patients, multisite artery disease represents a serious issue influencing evolution, outcomes and prognosis. We evaluated for the first time the power of the Myocardial Infarction SYNTAX Score (MI SS) and Clinical SYNTAX Score (MI CSS) as predictors for renal artery stenosis (RAS) in STEMI. We also stratified the study population according to the two scores, and identified the variables correlated with the higher score.

MATERIAL AND METHODS

We used data from the REN-ACS study, which included 181 consecutive patients prospectively investigated for presence of RAS (through renal angiography), arterial stiffness (carotid-femoral pulse wave velocity, cf-PWV) and hydration status (bioimpedance). MI SS and CSS were computed.

RESULTS

Multivariate regressions indicated that the independent variables correlated with MI SS were left ventricular ejection fraction < 40%, significant RAS (> 50%, defined as RAS+), history of heart failure, and multivascular coronary disease (CAD, p < 0.03 for each), while those correlated with MI CSS were RAS+, cf-PWV, history of CAD, multivascular CAD, cholesterol, and total body water (p < 0.02 for each). In order to evaluate the ability to predict RAS+ we generated receiver operating characteristics and areas under curves, and the Youden index for MI SS and CSS.

CONCLUSIONS

Both scores correlated with extensive atherosclerotic disease and presence of RAS+. A lower CSS proved to be a good predictor for exclusion of RAS+, with high specificity (85%) and negative predictive value (92%), and fair sensitivity (60%). We aim to further pursue this line of research and design a better predictor for RAS, with the inclusion of a novel biomarker in order to increase sensitivity.

Markers of increased atherosclerotic risk in patients with chronic kidney disease: a preliminary study

BACKGROUND

The prevalence of chronic kidney disease is rising continuously. Cardiovascular disease is among leading causes of death and premature mortality of patients with chronic kidney disease. Even the earliest stages of chronic kidney disease are associated with higher risk of subsequent coronary heart disease. The aim of this study was to determine markers of increased risk of atherosclerosis in CKD.

METHODS

The study group consisted of a total of 80 patients (20 patients with stage I/II CKD, 20 with stage III CKD, 20 stage IV CKD and 20 stage V/dialysis) and 24 healthy volunteers. Levels of proteins (osteoprotegerin, osteopontin, osteocalcin, matrix γ-carboxyglutamic acid protein, fetuin A, MMP-2, MMP-9, TIMP-1, TIMP-2) and biochemical parameters were measured to analyse their influence on atherosclerosis risk in CKD patients. Cardiac echocardiography was performed to assess structural integrity and function, presence of left ventricular hypertrophy and systolic and diastolic function dysfunction.

RESULTS

This study shows that the prevalence of ventricular hypertrophy (95.3 %) and diastolic dysfunction (93.2 %) in CKD patients is high. Also E/E' ratio was significantly higher (13.6 ± 4.4, p = 0.001), tricuspid insufficiency (27.3 in CKD I/II vs. 71.4 in CKD V, p = 0.016), contractile dysfunction (33.3 in CKD I/II vs. 78.9 in CKD V, p = 0.040), mitral valve calcification (0 in CKD I/II vs. 28.6 in CKD V, p = 0.044) and aortic valve calcification (0 in CKD I/II vs. 61.9 in CKD V, p = 0.0008) were significantly more frequent in patients with CKD stage V/dialysis than in other groups. Only MMP-2, MMP-2/TIMP-2 ratio and TIMP-1 differed significantly between groups.

CONCLUSIONS

This study shows high prevalence of ventricular hypertrophy and diastolic dysfunction in CKD patients. Contractile dysfunction, mitral and aortic valve calcification in HD patients were significantly more frequent than in patients with other CKD stages. Significantly increased levels of MMP-2, MMP-2/TIMP-2 ratio and lower TIMP-1 suggests that these factors may be involved in the pathogenesis of atherosclerosis in CKD patients.

Phosphate binders for the treatment of chronic kidney disease: role of iron oxyhydroxide

Chronic kidney disease-mineral bone disorder is frequent in patients with renal failure. It is characterized by abnormalities in mineral and bone metabolism with resulting hyperphosphatemia, low serum vitamin D, secondary hyperparathyroidism, altered bone morphology and strength, higher risk of bone fractures, and development of vascular or other soft tissue calcifications. Besides the recommendation to reduce phosphorus dietary intake, many drugs are currently available for the treatment of calcium/phosphate imbalance. Among them, phosphate binders represent a milestone. Calcium-based binders (calcium carbonate, calcium acetate) are effective in lowering serum phosphate, but their use has been associated with an increased risk of hypercalcemia and calcifications. Calcium-free binders (sevelamer hydrochloride, sevelamer carbonate, and lanthanum carbonate) are equally or slightly less effective than calcium-containing compounds. They would not induce an increase in calcium levels but may have relevant side effects, including gastrointestinal symptoms for sevelamer and risk of tissue accumulation for lanthanum. Accordingly, new phosphate binders are under investigation and some of them have already been approved. A promising option is sucroferric oxyhydroxide (Velphoro(®), PA21), an iron-based phosphate binder consisting of a mixture of polynuclear iron(III)-oxyhydroxide, sucrose, and starches. The present review is focused on pharmacology, mode of action, and pharmacokinetics of sucroferric oxyhydroxide, with a discussion on comparative efficacy, safety, and tolerability studies of this drug in chronic kidney disease and patient perspectives such as quality of life, satisfaction, and acceptability. Sucroferric oxyhydroxide has proven to be as effective as sevelamer in reducing phosphatemia with a similar safety profile and lower pill burden. Experimental and clinical studies have documented a minimal percentage of iron absorption without inducing toxicity. In conclusion, the overall benefit-risk balance of sucroferric oxyhydroxide is deemed to be positive, and this new drug may therefore represent a good alternative to traditional phosphate binders for the treatment of hyperphosphatemia in dialysis patients.