The impact of coronary angiography on renal transplant function

INTRODUCTION

There may be reluctance to perform coronary angiography in kidney transplant patients due to perceived risk of iodinated contrast, despite an increased risk of cardiovascular disease compared with the general population.

AIM

We sought to determine if renal transplant function was adversely affected within 7, 30 and 180 days of coronary angiography.

DESIGN AND METHODS

Renal transplant recipients undergoing coronary angiography in a single centre (01/2006-02/2018) were identified retrospectively. Baseline and highest SCr within 7, 30 and 180 days of coronary angiography were extracted from the electronic patient record. Rise in creatinine >26 micromol/l was considered significant [equivalent to Acute Kidney Injury (AKI) Network criteria stage 1 AKI] and case note review performed to determine circumstance of renal decline.

RESULTS

There were 127 coronary angiographies conducted in 90 patients: 67.7% were male and mean age was 58.0 (±10.1) years. There was AKI within 7 days in 18.9% cases, but SCr returned to baseline within 7 days or there was an alternative explanation for AKI in 83.3% of these. In the remaining four cases, there was progressive decline in renal transplant function. In the absence of critical illness, no patient required dialysis or extended hospital stay for contrast-associated AKI.

CONCLUSIONS

In this cohort of renal transplant recipients undergoing coronary angiography, AKI occurred in a minority of cases, and in more than 95% of such cases this effect was transient, with progressive renal decline a rare and predictable event. Renal transplant should not be regarded as a contraindication to coronary angiography.

Guidelines and clinical practice at the primary level of healthcare in patients with type 2 diabetes mellitus with and without kidney disease in five European countries

BACKGROUND

The number of patients with type 2 diabetes mellitus and diabetes mellitus-associated chronic kidney disease varies considerably between countries. Next to differences in genetic as well as life style risk factors, varying practices in medical care delivery might cause this diversity.

METHOD

The PROVALID study recruited 4000 patients with type 2 diabetes mellitus at the primary level of healthcare in five European countries (Austria, Hungary, The Netherlands, Poland and Scotland). Baseline data were used to describe patient characteristics and compare the adherence to ADA (American Diabetes Association) and KDIGO (Kidney Disease: Improving Global Outcomes) guidelines with respect to metabolic and blood pressure control, use of renin-angiotensin system-blocking agents, statins and acetylsalicylic acid between the countries.

RESULTS

About 34.8% of the population had evidence of diabetes mellitus-associated chronic kidney disease. The median HbA1c level of the cohort was 6.8% (ranging from 6.5 in Poland to 7.0% in Scotland). Mean blood pressure was 136/79 (±17/10) and significantly higher in subjects with elevated albuminuria. These individuals also were more often treated with renin-angiotensin system-blocking agents (74.1% vs 84.6%), whereas the use of statins was driven by cardiovascular comorbidity. Acetylsalicylic acid was used in only 28.9% subjects. Despite similar cardiovascular comorbidities and renal function, the use of renin-angiotensin system-blocking agents varied significantly between the countries from 66.7% to 87.4%. An even higher variability was observed for patients >40 years of age using statins (39.8%-82.7%) and administration of acetylsalicylic acid in patients older than 50 years (5.2%-43.8%).

CONCLUSION

Our study shows that medical practice in type 2 diabetes mellitus patients with and without renal disease is different in European countries. Longitudinal follow-up will reveal if this diversity affects clinical endpoints.

Author Correction: Lipid management in patients with chronic kidney disease

In the acknowledgements section of this article as originally published, information on the authors' roles as EURECAm members is missing. The correct acknowledgement is as follows: "This Review was planned as part of the activity of the European Renal and Cardiovascular Medicine working (EURECAm) group and all authors are EURECAm members. A.O.'s work was supported by Spanish Government ISCIII FEDER funds (PI16/02057, ISCIII-RETIC REDinREN RD16/0009) and Community of Madrid (B2017/BMD-3686 CIFRA2-CM). P.R.'s work is supported by a public grant overseen by the French National Research Agency (ANR) as part of the second "Investissements d'Avenir" program FIGHT-HF (reference: ANR-15-RHU-0004) and by the French PIA project "Lorraine Université d'Excellence", reference ANR-15-IDEX-04-LUE." The omission has been corrected in the PDF and HTML versions of the article.

Investigating the Relationship between Cerebral Blood Flow and Cognitive Function in Hemodialysis Patients

BACKGROUND

The immediate and longer-term effects of hemodialysis on cerebral circulation, cerebral structure, and cognitive function are poorly understood.

METHODS

In a prospective observational cohort study of 97 adults (median age 59 years) receiving chronic hemodialysis, we used transcranial Doppler ultrasound to measure cerebral arterial mean flow velocity (MFV) throughout dialysis. Using a well validated neuropsychological protocol, we assessed cognitive function during and off dialysis and after 12 months of treatment. We also used brain magnetic resonance imaging (MRI) to assess atrophy, white matter hyperintensities (WMHs), and diffusion parameters, and tested correlations between MFV, cognitive scores, and changes on MRI.

RESULTS

MFV declined significantly during dialysis, correlating with ultrafiltrate volumes. Percentage of decline in MFV correlated with intradialytic decline in cognitive function, including global function, executive function, and verbal fluency. At follow-up, 73 patients were available for repeat testing, 34 of whom underwent repeat MRI. In a subgroup of patients followed for 12 months of continued dialysis, percentage of decline in MFV correlated significantly with lower global and executive function and with progression of WMH burden (a marker of small vessel disease). Twelve of 15 patients who received renal transplants during follow-up had both early and follow-up off-dialysis assessments. After transplant, patients' memory (on a delayed recall test) improved significantly; increased fractional anisotropy of white matter (a measure of cerebral diffusion) in these patients correlated with improving executive function.

CONCLUSIONS

Patients undergoing hemodialysis experience transient decline in cerebral blood flow, correlating with intradialytic cognitive dysfunction. Progressive cerebrovascular disease occurred in those continuing dialysis, but not in transplanted patients. Cognitive function and cerebral diffusion improved after transplant.

Vitamin K status, supplementation and vascular disease: a systematic review and meta-analysis

OBJECTIVES

Vascular stiffness (VS) and vascular calcification (VC) are surrogate markers of vascular health associated with cardiovascular events. Vitamin K-dependent proteins (VKDP) are associated with VS and VC and require vitamin K for activity. We conducted a systematic review and meta-analysis of: (1) the effect of vitamin K supplementation on VS and VC and (2) association of inactive VKDP levels with incident cardiovascular disease and mortality.

METHODS

Two authors searched MEDLINE and Embase databases and Cochrane and ISRCTN registries for studies of vitamin K clinical trials that measured effects on VC, VS or VKDP and longitudinal studies assessing effect of VKDP on incident CVD or mortality. Random effects meta-analyses were performed.

RESULTS

Thirteen controlled clinical trials (n=2162) and 14 longitudinal studies (n=10 726) met prespecified inclusion criteria. Vitamin K supplementation was associated with significant reduction in VC (-9.1% (95% CI -17.7 to -0.5); p=0.04) and VKDP (desphospho-uncarboxylated matrix Gla protein; -44.7% (95% CI -65.1 to -24.3), p<0.0001) and uncarboxylated osteocalcin; -12.0% (95% CI -16.7 to -7.2), p<0.0001) compared with control, with a non-significant improvement in VS. In longitudinal studies with median follow-up of 7.8 (IQR 4.9-11.3) years, VKDP levels were associated with a combined endpoint of CVD or mortality (HR 0.45 (95% CI 0.07 to 0.83), p=0.02).

CONCLUSIONS

Supplementation with vitamin K significantly reduced VC, but not VS, compared with control. The conclusions drawn are limited by small numbers of studies with substantial heterogeneity. VKDP was associated with combined endpoint of CVD or mortality. Larger clinical trials of effect of vitamin K supplementation to improve VC, VS and long-term cardiovascular health are warranted.

TRIAL REGISTRATION NUMBER

CRD42017060344.

Predictors of atherosclerotic events in patients on haemodialysis: post hoc analyses from the AURORA study

Background

Patients on haemodialysis (HD) are at high risk for cardiovascular events, but heart failure and sudden death are more common than atherosclerotic events. The A Study to Evaluate the Use of Rosuvastatinin in Subjects on Regular Hemodialysis: An Assessment of Survival and Cardiovascular Events (AURORA) trial was designed to assess the effect of rosuvastatin on myocardial infarction and death from any cardiac cause in 2773 HD patients. We studied predictors of the atherosclerotic cardiovascular events in AURORA.

Methods

We readjudicated all deaths and presumed myocardial infarctions according to the criteria used in the Study of Heart and Renal Protection (SHARP); these were specifically developed to separate atherosclerotic from non-atherosclerotic cardiovascular events. The readjudicated atherosclerotic end point included the first event of the following: non-fatal myocardial infarction, fatal coronary heart disease, non-fatal and fatal non-haemorrhagic stroke, coronary revascularization procedures and death from ischaemic limb disease. Stepwise Cox regression analysis was used to identify the predictors of such events.

Results

During a mean follow-up of 3.2 years, 506 patients experienced the new composite atherosclerotic outcome. Age, male sex, prevalent diabetes, prior cardiovascular disease, weekly dialysis duration, baseline albumin [hazard ratio (HR) 0.96; 95% confidence interval (CI) 0.94-0.99 per g/L increase], high-sensitivity C-reactive protein (HR 1.13; 95% CI 1.04-1.22 per mg/L increase) and oxidized low-density lipoprotein (LDL) cholesterol (HR 1.09; 95% CI 1.03-1.17 per 10 U/L increase) were selected as significant predictors in the model. Neither LDL cholesterol nor allocation to placebo/rosuvastatin therapy predicted the outcome.

Conclusions

Even with the use of strict criteria for end point definition, non-traditional risk factors, but not lipid disturbances, predicted atherosclerotic events in HD patients.

Steroid regulation: An overlooked aspect of tolerance and chronic rejection in kidney transplantation

Steroid conversion (HSD11B1, HSD11B2, H6PD) and receptor genes (NR3C1, NR3C2) were examined in kidney-transplant recipients with "operational tolerance" and chronic rejection (CR), independently and within the context of 88 tolerance-associated genes. Associations with cellular types were explored. Peripheral whole-blood gene-expression levels (RT-qPCR-based) and cell counts were adjusted for immunosuppressant drug intake. Tolerant (n = 17), stable (n = 190) and CR patients (n = 37) were compared. Healthy controls (n = 14) were used as reference. The anti-inflammatory glucocorticoid receptor (NR3C1) and the cortisol-activating HSD11B1 and H6PD genes were up-regulated in CR and were lowest in tolerant patients. The pro-inflammatory mineralocorticoid gene (NR3C2) was downregulated in stable and CR patients. NR3C1 was associated with neutrophils and NR3C2 with T-cells. Steroid conversion and receptor genes, alone, enabled classification of tolerant patients and were major contributors to gene-expression signatures of both, tolerance and CR, alongside known tolerance-associated genes, revealing a key role of steroid regulation and response in kidney transplantation.

Magnetic resonance imaging biomarkers for chronic kidney disease: a position paper from the European Cooperation in Science and Technology Action PARENCHIMA

Functional renal magnetic resonance imaging (MRI) has seen a number of recent advances, and techniques are now available that can generate quantitative imaging biomarkers with the potential to improve the management of kidney disease. Such biomarkers are sensitive to changes in renal blood flow, tissue perfusion, oxygenation and microstructure (including inflammation and fibrosis), processes that are important in a range of renal diseases including chronic kidney disease. However, several challenges remain to move these techniques towards clinical adoption, from technical validation through biological and clinical validation, to demonstration of cost-effectiveness and regulatory qualification. To address these challenges, the European Cooperation in Science and Technology Action PARENCHIMA was initiated in early 2017. PARENCHIMA is a multidisciplinary pan-European network with an overarching aim of eliminating the main barriers to the broader evaluation, commercial exploitation and clinical use of renal MRI biomarkers. This position paper lays out PARENCHIMA's vision on key clinical questions that MRI must address to become more widely used in patients with kidney disease, first within research settings and ultimately in clinical practice. We then present a series of practical recommendations to accelerate the study and translation of these techniques.

Validation of Plasma Biomarker Candidates for the Prediction of eGFR Decline in Patients With Type 2 Diabetes

OBJECTIVE

The decline of estimated glomerular filtration rate (eGFR) in patients with type 2 diabetes is variable, and early interventions would likely be cost-effective. We elucidated the contribution of 17 plasma biomarkers to the prediction of eGFR loss on top of clinical risk factors.

RESEARCH DESIGN AND METHODS

We studied participants in PROVALID (PROspective cohort study in patients with type 2 diabetes mellitus for VALIDation of biomarkers), a prospective multinational cohort study of patients with type 2 diabetes and a follow-up of more than 24 months (n = 2,560; baseline median eGFR, 84 mL/min/1.73 m²; urine albumin-to-creatinine ratio, 8.1 mg/g). The 17 biomarkers were measured at baseline in 481 samples using Luminex and ELISA. The prediction of eGFR decline was evaluated by linear mixed modeling.

RESULTS

In univariable analyses, 9 of the 17 markers showed significant differences in median concentration between stable and fast-progressing patients. A linear mixed model for eGFR obtained by variable selection exhibited an adjusted R² of 62%. A panel of 12 biomarkers was selected by the procedure and accounted for 34% of the total explained variability, of which 32% was due to 5 markers. The individual contribution of each biomarker to the prediction of eGFR decline on top of clinical predictors was generally low. When included into the model, baseline eGFR exhibited the largest explained variability of eGFR decline (R² of 79%), and the contribution of each biomarker dropped below 1%.

CONCLUSIONS

In this longitudinal study of patients with type 2 diabetes and maintained eGFR at baseline, 12 of the 17 candidate biomarkers were associated with eGFR decline, but their predictive power was low.

Circulating amino acids and the risk of macrovascular, microvascular and mortality outcomes in individuals with type 2 diabetes: results from the ADVANCE trial

AIMS/HYPOTHESES

We aimed to quantify the association of individual circulating amino acids with macrovascular disease, microvascular disease and all-cause mortality in individuals with type 2 diabetes.

METHODS

We performed a case-cohort study (N = 3587), including 655 macrovascular events, 342 microvascular events (new or worsening nephropathy or retinopathy) and 632 all-cause mortality events during follow-up, in a secondary analysis of the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) study. For this study, phenylalanine, isoleucine, glutamine, leucine, alanine, tyrosine, histidine and valine were measured in stored plasma samples by proton NMR metabolomics. Hazard ratios were modelled per SD increase in each amino acid.

RESULTS

In models investigating associations and potential mechanisms, after adjusting for age, sex and randomised treatment, phenylalanine was positively, and histidine inversely, associated with macrovascular disease risk. These associations were attenuated to the null on further adjustment for extended classical risk factors (including eGFR and urinary albumin/creatinine ratio). After adjustment for extended classical risk factors, higher tyrosine and alanine levels were associated with decreased risk of microvascular disease (HR 0.78; 95% CI 0.67, 0.91 and HR 0.86; 95% CI 0.76, 0.98, respectively). Higher leucine (HR 0.79; 95% CI 0.69, 0.90), histidine (HR 0.89; 95% CI 0.81, 0.99) and valine (HR 0.79; 95% CI 0.70, 0.88) levels were associated with lower risk of mortality. Investigating the predictive ability of amino acids, addition of all amino acids to a risk score modestly improved classification of participants for macrovascular (continuous net reclassification index [NRI] +35.5%, p < 0.001) and microvascular events (continuous NRI +14.4%, p = 0.012).

CONCLUSIONS/INTERPRETATION

We report distinct associations between circulating amino acids and risk of different major complications of diabetes. Low tyrosine appears to be a marker of microvascular risk in individuals with type 2 diabetes independently of fundamental markers of kidney function.

Long- and short-term outcomes in renal allografts with deceased donors: A large recipient and donor genome-wide association study

Improvements in immunosuppression have modified short-term survival of deceased-donor allografts, but not their rate of long-term failure. Mismatches between donor and recipient HLA play an important role in the acute and chronic allogeneic immune response against the graft. Perfect matching at clinically relevant HLA loci does not obviate the need for immunosuppression, suggesting that additional genetic variation plays a critical role in both short- and long-term graft outcomes. By combining patient data and samples from supranational cohorts across the United Kingdom and European Union, we performed the first large-scale genome-wide association study analyzing both donor and recipient DNA in 2094 complete renal transplant-pairs with replication in 5866 complete pairs. We studied deceased-donor grafts allocated on the basis of preferential HLA matching, which provided some control for HLA genetic effects. No strong donor or recipient genetic effects contributing to long- or short-term allograft survival were found outside the HLA region. We discuss the implications for future research and clinical application.

Inequality in Care and Differences in Outcome Following Stroke in People With ESRD

Introduction

Stroke rate and mortality are greater in individuals with end-stage renal disease (ESRD) than in those without ESRD. We examined discrepancies in stroke care in ESRD patients and their influence on mortality.

Methods

This is a national record linkage cohort study of hospitalized stroke individuals from 2005 to 2013. Presentation, measures of care quality (admission to stroke unit, swallow assessment, antithrombotics, or thrombolysis use), and outcomes were compared in those with and without ESRD after propensity score matching (PSM). We examined the effect of being admitted to a stroke unit on survival using Kaplan-Meier and Cox survival analyses.

Results

A total of 8757 individuals with ESRD and 61,367 individuals with stroke were identified. ESRD patients (n =486) experienced stroke over 34,551.9 patient-years of follow-up; incidence rates were 25.3 (dialysis) and 4.5 (kidney transplant)/1000 patient-years. After PSM, dialysis patients were less likely to be functionally independent (61.4% vs. 77.7%; P < 0.0001) before stroke, less frequently admitted to stroke units (64.6% vs. 79.6%; P < 0.001), or to receive aspirin (75.3% vs. 83.2%; P = 0.01) than non-ESRD stroke patients. There were no significant differences in management of kidney transplantation patients. Stroke with ESRD was associated with a higher death rate during admission (dialysis 22.9% vs.14.4%, P = 0.002; transplantation: 19.6% vs. 9.3%; P = 0.034). Managing ESRD patients in a stroke unit was associated with a lower risk of death at follow-up (hazard ratio: 0.68; 95% confidence interval: 0.55-0.84).

Conclusion

Stroke incidence is high in ESRD. Individuals on dialysis are functionally more dependent before stroke and less frequently receive optimal stroke care. After a stroke, death is more likely in ESRD patients. Acute stroke unit care may be associated with lower mortality.

Association of Total and Differential Leukocyte Counts With Cardiovascular Disease and Mortality in the UK Biobank

OBJECTIVE

Elevated white blood cell count is associated with a higher risk of cardiovascular disease (CVD). We aimed to investigate whether specific leukocyte subpopulations, which may more closely indicate a specific inflammatory pathway, are specifically associated with CVD.

APPROACH AND RESULTS

Participants (478 259) from UK Biobank with data for white blood cell count were included. Death because of CVD (n=1377) and non-CVD causes (n=8987) occurred during median follow-up time of 7.0 years (interquartile range, 6.3-7.6). In Cox models, deciles of leukocyte counts (lymphocytes, monocytes, neutrophils, eosinophils, and basophils) were examined using the fifth decile as the referent group. Models were stratified by sex and adjusted for a range of classical risk factors. A sensitivity analysis excluded participants with baseline comorbidites and the first 2 years of follow-up. Men (hazard ratio [HR], 1.59; 95% confidence interval, 1.22-2.08) and women (HR, 2.15; 95% confidence interval, 1.38-3.35) in the highest decile of neutrophil count were at higher risk of CVD mortality and nonfatal CVD (men HR, 1.28; 95% confidence interval, 1.16-1.42 and women HR, 1.21; 95% confidence interval, 1.06-1.38). In the sensitivity analysis, the power to investigate CVD mortality was limited, but for both sexes combined, the linear HRs for a 1×10⁹/L cell count increase in white blood cell count and neutrophils, respectively, was 1.05 (1.03-1.07) and 1.07 (1.04-1.11).

CONCLUSIONS

Among circulating leukocyte subpopulations, neutrophil count in men was most consistently associated with fatal and nonfatal CVD. Further studies of interventions that lower circulating neutrophils, such as canakinumab, are required to investigate causality.

What happens to the heart in chronic kidney disease?

Cardiovascular disease is common in patients with chronic kidney disease. The increased risk of cardiovascular disease seen in this population is attributable to both traditional and novel vascular risk factors. Risk of sudden cardiac or arrhythmogenic death is greatly exaggerated in chronic kidney disease, particularly in patients with end stage renal disease where the risk is roughly 20 times that of the general population. The reasons for this increased risk are not entirely understood and while atherosclerosis is accelerated in the presence of chronic kidney disease, premature myocardial infarction does not solely account for the excess risk. Recent work demonstrates that the structure and function of the heart starts to alter early in chronic kidney disease, independent of other risk factors. The implications of cardiac remodelling and hypertrophy may predispose chronic kidney disease patients to heart failure, arrhythmia and myocardial ischaemia. Further research is needed to minimise cardiovascular risk associated with structural and functional heart disease associated with chronic kidney disease.

Deleterious effects of phosphate on vascular and endothelial function via disruption to the nitric oxide pathway

Background

Hyperphosphataemia is an independent risk factor for accelerated cardiovascular disease in chronic kidney disease (CKD), although the mechanism for this is poorly understood. We investigated the effects of sustained exposure to a high-phosphate environment on endothelial function in cellular and preclinical models, as well as in human subjects.

Methods

Resistance vessels from rats and humans (± CKD) were incubated in a normal (1.18 mM) or high (2.5 mM) phosphate concentration solution and cells were cultured in normal- (0.5 mM) or high-phosphate (3 mM) concentration media. A single-blind crossover study was performed in healthy volunteers, receiving phosphate supplements or a phosphate binder (lanthanum), and endothelial function measured was by flow-mediated dilatation.

Results

Endothelium-dependent vasodilatation was impaired when resistance vessels were exposed to high phosphate; this could be reversed in the presence of a phosphodiesterase-5-inhibitor. Vessels from patients with CKD relaxed normally when incubated in normal-phosphate conditions, suggesting that the detrimental effects of phosphate may be reversible. Exposure to high-phosphate disrupted the whole nitric oxide pathway with reduced nitric oxide and cyclic guanosine monophosphate production and total and phospho endothelial nitric oxide synthase expression. In humans, endothelial function was reduced by chronic phosphate loading independent of serum phosphate, but was associated with higher urinary phosphate excretion and serum fibroblast growth factor 23.

Conclusions

These directly detrimental effects of phosphate, independent of other factors in the uraemic environment, may explain the increased cardiovascular risk associated with phosphate in CKD.

A Prospective Cohort Study in Patients with Type 2 Diabetes Mellitus for Validation of Biomarkers (PROVALID) - Study Design and Baseline Characteristics

BACKGROUND/AIMS

The prevalence of diabetes mellitus type 2 and kidney disease in these patients varies widely between European countries.

METHODS

In addition to store bio-samples the "Prospective cohort study in patients with type 2 diabetes mellitus for validation of biomarkers" collects information on history, physical status, laboratory measurements and medication in 4000 patients with diabetes mellitus type 2, being taken care of at the primary level of healthcare in 5 European countries (Austria, Hungary, Netherlands, Poland and Scotland). Next to comparing the rate of loss of eGFR between the countries, a further objective of the PROVALID study is to determine the 5-year cumulative incidence of renal and cardiovascular outcomes.

RESULTS

The mean age of the population recruited is 62.9±10 years, 54.6% are male and the mean BMI is 30.9±5.4 kg/m2. Metabolic control (median HBA1c 6.8 % (6.2; 7.5)) is achieved via administration of metformin in 67.4% of the patients and insulin in 30.3%. Median systolic and diastolic blood pressure at recruitment is 135 (125; 146) and 80 (72; 85) mmHg, 65.4% of subjects received RAAS blocking agents. Mean eGFR is 80.7±29.2 ml/min/1.73m2 and median baseline albumin/creatinine ratio 8.3 mg (IQR: 3.8 and 25.1).

CONCLUSION

PROVALID will provide information on incidence and progression of renal and cardiovascular disease and therapy in patients with type 2 diabetes mellitus in different European countries. Thus, in contrast to many other cohort studies we will be able to associate national clinical practise pattern with outcome in this highly vulnerable patient population.

Ascorbic acid lowers central blood pressure and asymmetric dimethylarginine in chronic kidney disease

Background

Premature cardiovascular disease in patients with chronic kidney disease (CKD) is not explained by traditional risk factors and oxidative stress may contribute via endothelial and vascular dysfunction. We investigated the effect of ascorbic acid on oxidative stress and vascular function in CKD patients compared with controls with hypertension (HTN).

Methods

A crossover study of intravenous saline and ascorbic acid was conducted. Biomarkers of oxidative stress were measured, while pulse wave analysis and brachial flow-mediated dilatation were performed to assess large artery and endothelial function.

Results

Twenty HTN and 30 CKD patients Stages 3–5 were recruited. Serum ascorbic acid was significantly lower in patients with CKD. In both groups, ascorbic acid significantly increased total antioxidant potential and superoxide. Asymmetric dimethylarginine (ADMA) was reduced significantly by ascorbic acid in the CKD group and on multivariate regression analysis, age and the presence of CKD were predictors of ADMA response to ascorbic acid. Although no effect on FMD was observed, central blood pressure and augmentation index were reduced significantly in both groups.

Conclusions

Ascorbic acid has pro- and antioxidant effects, reducing central blood pressure and augmentation index in HTN and CKD. Ascorbic acid reduces serum ADMA in CKD, which may have longer-term benefits.

Characterizing Cardiac Involvement in Chronic Kidney Disease Using CMR-a Systematic Review

PURPOSE OF REVIEW

The aim of the review was to identify and describe recent advances (over the last 3 years) in cardiac magnetic resonance (CMR) imaging in patients with chronic kidney disease (CKD). We conducted a literature review in line with current guidelines.

RECENT FINDINGS

The authors identified 22 studies. Patients with CKD had left ventricular global and regional dysfunction and adverse remodeling. Stress testing with CMR revealed a reduced stress-response in CKD patients. Native T1 relaxation times (as a surrogate markers of fibrosis) are elevated in CKD patients, proportional to disease duration. Patients with CKD have reduced strain magnitudes and reduced aortic distensibility.

SUMMARY

CMR has diagnostic utility to identify and characterize cardiac involvement in this patient group. A number of papers have described novel findings over the last 3 years, suggesting that CMR has potential to become more widely used in studies in this patient group.

Risk Factors for Prognosis in Patients With Severely Decreased GFR

Introduction

Patients with chronic kidney disease (CKD) and estimated glomerular filtration rate (eGFR) <30 ml/min per 1.73 m² (corresponding to CKD stage G4+) comprise a minority of the overall CKD population but have the highest risk for adverse outcomes. Many CKD G4+ patients are older with multiple comorbidities, which may distort associations between risk factors and clinical outcomes.

Methods

We undertook a meta-analysis of risk factors for kidney failure treated with kidney replacement therapy (KRT), cardiovascular disease (CVD) events, and death in participants with CKD G4+ from 28 cohorts (n = 185,024) across the world who were part of the CKD Prognosis Consortium.

Results

In the fully adjusted meta-analysis, risk factors associated with KRT were time-varying CVD, male sex, black race, diabetes, lower eGFR, and higher albuminuria and systolic blood pressure. Age was associated with a lower risk of KRT (adjusted hazard ratio: 0.74; 95% confidence interval: 0.69–0.80) overall, and also in the subgroup of individuals younger than 65 years. The risk factors for CVD events included male sex, history of CVD, diabetes, lower eGFR, higher albuminuria, and the onset of KRT. Systolic blood pressure showed a U-shaped association with CVD events. Risk factors for mortality were similar to those for CVD events but also included smoking. Most risk factors had qualitatively consistent associations across cohorts.

Conclusion

Traditional CVD risk factors are of prognostic value in individuals with an eGFR <30 ml/min per 1.73 m², although the risk estimates vary for kidney and CVD outcomes. These results should encourage interventional studies on correcting risk factors in this high-risk population.

The utility of anti-Müllerian hormone in women with chronic kidney disease, on haemodialysis and after kidney transplantation

Women with renal disease have menstrual and gonadal dysfunction manifesting as hormonal imbalance. Anti-Müllerian hormone (AMH) is a potential measure of ovarian reserve. We examined circulating AMH concentrations in young women with renal failure, determined associations with clinical characteristics, and compared AMH with age-matched healthy individuals. AMH was measured in 77 women: 26 had chronic kidney disease (CKD), 26 were on haemodialysis (HD), and 25 had a kidney transplant. Random AMH levels were highest in women on HD [HD 2.9 (1.1-5.2), CKD 1.6 (0.7-2.2), transplant 1.5 (1.0-4.2) ng/ml]. On multiple linear regression, AMH was 53% higher [95% CI 0.20-0.98, P = 0.002] in women on HD and decreased by 20% per 5-year increase in age (P < 0.001). AMH was 43% lower in women with renal failure compared with 600 age-matched controls [1.7 (0.9-3.8) versus 3.0 (1.9-5.0) ng/ml, P < 0.001]; however, we found no difference in AMH between those on HD and healthy individuals [2.9 (1.1-5.2) versus 3.0 (1.9-5.0) ng/ml]. AMH may be a useful biomarker in female renal patients with non-dialysis dependent renal disease pursuing pregnancy. In contrast, AMH levels are higher in HD but unlikely to reflect ovarian reserve.

Continued monitoring of acute kidney injury survivors might not be necessary in those regaining an estimated glomerular filtration rate >60 mL/min at 1 year

Background

Severe acute kidney injury (AKI) among hospitalized patients often necessitates initiation of short-term dialysis. Little is known about the long-term outcome of those who recover to normal renal function. The aim of this study was to determine the long-term renal outcome of patients experiencing AKI requiring dialysis secondary to hypoperfusion injury and/or sepsis who recovered to apparently normal renal function.

Methods

All adult patients with AKI requiring dialysis in our centre between 1 January 1980 and 31 December 2010 were identified. We included patients who had estimated glomerular filtration rate (eGFR) >60 mL/min/1.73 m 2 12 months or later after the episode of AKI. Patients were followed up until 3 March 2015. The primary outcome was time to chronic kidney disease (CKD) (defined as eGFR persistently <60 mL/min/1.73 m 2 ) from first dialysis for AKI.

Results

Among 2922 patients with a single episode of dialysis-requiring AKI, 396 patients met the study inclusion criteria. The mean age was 49.8 (standard deviation 16.5) years and median follow-up was 7.9 [interquartile range (IQR) 4.8-12.7] years. Thirty-five (8.8%) of the patients ultimately developed CKD after a median of 5.3 (IQR 2.8-8.0) years from first dialysis for AKI giving an incidence rate of 1 per 100 person-years. Increasing age, diabetes and vascular disease were associated with higher risk of progression to CKD [adjusted hazard ratios (95% confidence interval): 1.06 (1.03, 1.09), 3.05 (1.41, 6.57) and 3.56 (1.80, 7.03), respectively].

Conclusions

Recovery from AKI necessitating in-hospital dialysis was associated with a very low risk of progression to CKD. Most of the patients who progressed to CKD had concurrent medical conditions meriting monitoring of renal function. Therefore, it seems unlikely that regular follow-up of renal function is beneficial in patients who recover to eGFR >60 mL/min/1.73 m 2 by 12 months after an episode of AKI.

New Model for Estimating Glomerular Filtration Rate in Patients With Cancer

Purpose The glomerular filtration rate (GFR) is essential for carboplatin chemotherapy dosing; however, the best method to estimate GFR in patients with cancer is unknown. We identify the most accurate and least biased method. Methods We obtained data on age, sex, height, weight, serum creatinine concentrations, and results for GFR from chromium-51 (51Cr) EDTA excretion measurements (51Cr-EDTA GFR) from white patients ≥ 18 years of age with histologically confirmed cancer diagnoses at the Cambridge University Hospital NHS Trust, United Kingdom. We developed a new multivariable linear model for GFR using statistical regression analysis. 51Cr-EDTA GFR was compared with the estimated GFR (eGFR) from seven published models and our new model, using the statistics root-mean-squared-error (RMSE) and median residual and on an internal and external validation data set. We performed a comparison of carboplatin dosing accuracy on the basis of an absolute percentage error > 20%. Results Between August 2006 and January 2013, data from 2,471 patients were obtained. The new model improved the eGFR accuracy (RMSE, 15.00 mL/min; 95% CI, 14.12 to 16.00 mL/min) compared with all published models. Body surface area (BSA)-adjusted chronic kidney disease epidemiology (CKD-EPI) was the most accurate published model for eGFR (RMSE, 16.30 mL/min; 95% CI, 15.34 to 17.38 mL/min) for the internal validation set. Importantly, the new model reduced the fraction of patients with a carboplatin dose absolute percentage error > 20% to 14.17% in contrast to 18.62% for the BSA-adjusted CKD-EPI and 25.51% for the Cockcroft-Gault formula. The results were externally validated. Conclusion In a large data set from patients with cancer, BSA-adjusted CKD-EPI is the most accurate published model to predict GFR. The new model improves this estimation and may present a new standard of care.

Ferumoxytol-enhanced magnetic resonance angiography for the assessment of potential kidney transplant recipients

Objectives

Traditional contrast-enhanced methods for scanning blood vessels using magnetic resonance imaging (MRI) or CT carry potential risks for patients with advanced kidney disease. Ferumoxytol is a superparamagnetic iron oxide nanoparticle preparation that has potential as an MRI contrast agent in assessing the vasculature.

Methods

Twenty patients with advanced kidney disease requiring aorto-iliac vascular imaging as part of pre-operative kidney transplant candidacy assessment underwent ferumoxytol-enhanced magnetic resonance angiography (FeMRA) between December 2015 and August 2016. All scans were performed for clinical indications where standard imaging techniques were deemed potentially harmful or inconclusive. Image quality was evaluated for both arterial and venous compartments.

Results

First-pass and steady-state FeMRA using incremental doses of up to 4 mg/kg body weight of ferumoxytol as intravenous contrast agent for vascular enhancement was performed. Good arterial and venous enhancements were achieved, and FeMRA was not limited by calcification in assessing the arterial lumen. The scans were diagnostic and all patients completed their studies without adverse events.

Conclusions

Our preliminary experience supports the feasibility and utility of FeMRA for vascular imaging in patients with advanced kidney disease due for transplant listing, which has the advantages of obtaining both arteriography and venography using a single test without nephrotoxicity.

Key Points

• Evaluation of vascular disease is important in planning kidney transplantation.

• Standard vascular imaging methods are often problematic in kidney disease patients.

• FeMRA has the advantage of arteriography and venography in a single test.

• FeMRA is safe and non-nephrotoxic.

• FeMRA is not limited by arterial calcification.