Evaluation of arteriovenous fistula for hemodialysis with a new generation digital stethoscope: a pilot study

BACKGROUND AND AIMS

The management of complications of arteriovenous fistula (AVF) for hemodialysis, principally stenosis, remains a major challenge for clinicians with a substantial impact on health resources. Stenosis not infrequently preludes to thrombotic events with the loss of AVF functionality. A functioning AVF, when listened by a stethoscope, has a continuous systolic-diastolic low-frequency murmur, while with stenosis, the frequency of the murmur increases and the duration of diastolic component decreases, disappearing in severe stenosis. These evidences are strictly subjective and dependent from operator skill and experience. New generation digital stethoscopes are able to record sound and subsequently dedicated software allows to extract quantitative variables that characterize the sound in an absolutely objective and repeatable way. The aim of our study was to analyze with an appropriate software sounds from AVFs taken by a commercial digital stethoscope and to investigate the potentiality to develop an objective way to detect stenosis.

METHODS

Between September 2022 and January 2023, 64 chronic hemodialysis (HD) patients were screened by two blinded experienced examiners for recognized criteria for stenosis by Doppler ultrasound (DUS) and, consequently, the sound coming from the AVFs using a 3 M™ Littmann® CORE Digital Stethoscope 8570 in standardized sites was recorded. The sound waves were transformed into quantitative variables (amplitude and frequency) using a sound analysis software. The practical usefulness of the core digital stethoscope for a quick identification of an AVF stenosis was further evaluated through a pragmatic trial. Eight young nephrologist trainees underwent a simple auscultatory training consisting of two sessions of sound auscultation focusing two times on a "normal" AVF sound by placing the digital stethoscope on a convenience site of a functional AVF.

RESULTS

In 48 patients eligible, all sound components displayed, alone, a remarkable diagnostic capacity. More in detail, the AUC of the average power was 0.872 [95% CI 0.729-0.951], while that of the mean normalized frequency was 0.822 [95% 0.656-0.930]. From a total of 32 auscultations (eight different block sequences, each one comprising four auscultations), the young clinicians were able to identify the correct sound (stenosis/normal AVF) in 25 cases, corresponding to an overall accuracy of 78.12% (95% CI 60.03-90.72%).

CONCLUSIONS

The analysis of sound waves by a digital stethoscope permitted us to distinguish between stenotic and no stenotic AVFs. The standardization of this technique and the introducing of data in a deep learning algorithm could allow an objective and fast method for a frequent monitoring of AVF.

Hypoxia-inducible factor prolyl hydroxylase inhibitors for anaemia in chronic kidney disease: a document by the European Renal Best Practice board of the European Renal Association

Anaemia is a common complication of chronic kidney disease (CKD) and is associated with poor long-term outcomes and quality of life. The use of supplemental iron, erythropoiesis stimulating agents (ESAs) and blood transfusions has been the mainstay of treatment of anaemia in CKD for more than three decades. Despite available treatments, CKD patients with anaemia are undertreated and moderate-to-severe anaemia remains prevalent in the CKD population. Anaemia has consistently been associated with greater mortality, hospitalisation, cardiovascular events, and CKD progression in patients with CKD, and the risk increases with anaemia severity. Hypoxia-inducible factor (HIF) prolyl hydroxylase (PH) inhibitors have a novel mechanism of action by mimicking the body's response to hypoxia and have emerged as an alternative to ESAs for the treatment of anaemia in CKD. Their efficacy in correcting and maintaining haemoglobin has been demonstrated in over 30 phase 3 clinical trials. Additionally, HIF activation results in various pleiotropic effects beyond erythropoiesis with cholesterol reduction and improved iron homeostasis and potential anti-inflammatory effects. The long-term safety of these agents, particularly with respect to cardiovascular and thromboembolic events, and their possible effect on tumor growth requires to be fully elucidated. This document presents in detail the effects of HIF-PH inhibitors, describes their mechanisms of action and pharmacologic properties, and discusses their place in the treatment of anaemia in CKD according to the available evidence.

Spice Up Your Kidney: A Review on the Effects of Capsaicin in Renal Physiology and Disease

Capsaicin, the organic compound which attributes the spicy flavor and taste of red peppers and chili peppers, has been extensively studied for centuries as a potential natural remedy for the treatment of several illnesses. Indeed, this compound exerts well-known systemic pleiotropic effects and may thus bring important benefits against various pathological conditions like neuropathic pain, rhinitis, itching, or chronic inflammation. Yet, little is known about the possible biological activity of capsaicin at the kidney level, as this aspect has only been addressed by sparse experimental investigations. In this paper, we aimed to review the available evidence focusing specifically on the effects of capsaicin on renal physiology, as well as its potential benefits for the treatment of various kidney disorders. Capsaicin may indeed modulate various aspects of renal function and renal nervous activity. On the other hand, the observed experimental benefits in preventing acute kidney injury, slowing down the progression of diabetic and chronic kidney disease, ameliorating hypertension, and even delaying renal cancer growth may set the stage for future human trials of capsaicin administration as an adjuvant or preventive therapy for different, difficult-to-treat renal diseases.

Sleep apnoea syndrome prevalence in chronic kidney disease and end-stage kidney disease patients: a systematic review and meta-analysis

Background

Several studies have examined the frequency of sleep apnoea (SA) in patients with chronic kidney disease (CKD), reporting different prevalence rates. Our systematic review and meta-analysis aimed to define the clinical penetrance of SA in CKD and end-stage kidney disease (ESKD) patients.

Methods

Ovid-MEDLINE and PubMed databases were explored up to 5 June 2023 to identify studies providing SA prevalence in CKD and ESKD patients assessed by different diagnostic methods, either sleep questionnaires or respiration monitoring equipment [such as polysomnography (PSG), type III portable monitors or other diagnostic tools]. Single-study data were pooled using the random-effects model. The Chi2 and Cochrane-I2 tests were used to assess the presence of heterogeneity, which was explored performing sensitivity and/or subgroup analyses.

Results

A cumulative analysis from 32 single-study data revealed a prevalence of SA of 57% [95% confidence interval (CI) 42%-71%] in the CKD population, whereas a prevalence of 49% (95% CI 47%-52%) was found pooling data from 91 studies in ESKD individuals. The prevalence of SA using instrumental sleep monitoring devices, including classical PSG and type III portable sleep monitors, was 62% (95% CI 52%-72%) and 56% (95% CI 42%-69%) in CKD and ESKD populations, respectively. Sleep questionnaires revealed a prevalence of 33% (95% CI 16%-49%) and 39% (95% CI 30%-49%).

Conclusions

SA is commonly seen in both non-dialysis CKD and ESKD patients. Sleep-related questionnaires underestimated the presence of SA in this population. This emphasizes the need to use objective diagnostic tools to identify such a syndrome in kidney disease.

Chronic kidney disease: the missing concept in the 2019 EULAR/ERA-EDTA recommendations for lupus nephritis

Chronic kidney disease (CKD) is diagnosed when glomerular filtration rate (GFR) falls below 60 ml/min/1.73 m2 or urinary albumin:creatinine ratio (UACR) reaches ≥30 mg/g, as these two thresholds indicate a higher risk of adverse health outcomes, including cardiovascular mortality. CKD is classified as mild, moderate or severe, based on GFR and UACR values, and the latter two classifications convey a high or very high cardiovascular risk, respectively. Additionally, CKD can be diagnosed based on abnormalities detected by histology or imaging. Lupus nephritis (LN) is a cause of CKD. Despite the high cardiovascular mortality of patients with LN, neither albuminuria nor CKD are discussed in the 2019 European League Against Rheumatism (EULAR)/European Renal Association-European Dialysis and Transplant Association recommendations for the management of LN or the more recent 2022 EULAR recommendations for cardiovascular risk management in rheumatic and musculoskeletal diseases. Indeed, the proteinuria target values discussed in the recommendations may be present in patients with severe CKD and a very high cardiovascular risk who may benefit from guidance detailed in the 2021 European Society of Cardiology guidelines on cardiovascular disease prevention in clinical practice. We propose that the recommendations should move from a conceptual framework of LN as an entity separate from CKD to a framework in which LN is considered a cause of CKD and evidence generated from large CKD trials applies unless demonstrated otherwise.

Childhood Obesity: Insight into Kidney Involvement

This review examines the impact of childhood obesity on the kidney from an epidemiological, pathogenetic, clinical, and pathological perspective, with the aim of providing pediatricians and nephrologists with the most current data on this topic. The prevalence of childhood obesity and chronic kidney disease (CKD) is steadily increasing worldwide, reaching epidemic proportions. While the impact of obesity in children with CKD is less pronounced than in adults, recent studies suggest a similar trend in the child population. This is likely due to the significant association between obesity and the two leading causes of end-stage renal disease (ESRD): diabetes mellitus (DM) and hypertension. Obesity is a complex, systemic disease that reflects interactions between environmental and genetic factors. A key mechanism of kidney damage is related to metabolic syndrome and insulin resistance. Therefore, we can speculate about an adipose tissue-kidney axis in which neurohormonal and immunological mechanisms exacerbate complications resulting from obesity. Adipose tissue, now recognized as an endocrine organ, secretes cytokines called adipokines that may induce adaptive or maladaptive responses in renal cells, leading to kidney fibrosis. The impact of obesity on kidney transplant-related outcomes for both donors and recipients is also significant, making stringent preventive measures critical in the pre- and post-transplant phases. The challenge lies in identifying renal involvement as early as possible, as it is often completely asymptomatic and not detectable through common markers of kidney function. Ongoing research into innovative technologies, such as proteomics and metabolomics, aims to identify new biomarkers and is constantly evolving. Many aspects of pediatric disease progression in the population of children with obesity still require clarification. However, the latest scientific evidence in the field of nephrology offers glimpses into various new perspectives, such as genetic factors, comorbidities, and novel biomarkers. Investigating these aspects early could potentially improve the prognosis of these young patients through new diagnostic and therapeutic strategies. Hence, the aim of this review is to provide a comprehensive exploration of the pathogenetic mechanisms and prevalent pathological patterns of kidney damage observed in children with obesity.

Self-Reported Physical Inactivity and Mood Disturbances in End-Stage Kidney Disease (ESKD) Patients on Chronic Dialysis Treatment

BACKGROUND

Physical inactivity and mood disturbances are key issues in individuals with end-stage kidney disease (ESKD) and may lead to poor clinical outcomes.

METHODS

We performed a pilot, observational study to explore the possible relationships between the self-reported level of physical activity (IPAQ) and the severity of mood disturbances (BDI score) in a cohort of 58 ESKD patients undergoing chronic hemodialysis (HD; n = 30) or peritoneal dialysis (PD; n = 28).

RESULTS

Overall, ESKD patients were severely inactive (median METs: 590 [460-1850]) and the intensity of overall and walking physical activity was mostly low to moderate. HD individuals appeared less active than PD (METs 550 [250-1600] vs. 1080 [750-1730]; p = 0.003) and were also less prone to walking (METs 180 ± 90 vs. 320 ± 100; p = 0.01), while a barely statistical difference was noticed for the time spent sitting. ESKD individuals displayed a median BDI score of 17 [12-21], which indicated, on average, the presence of borderline depression, which was apparently more evident among HD individuals. A strong, inverse correlation was found between self-reported METs and BDI scores (R = -0.78; p < 0.0001), while such scores paralleled the time spent sitting during a weekday (R = 0.45; p = 0.0004) and a weekend day (R = 0.40; p = 0.002).

CONCLUSIONS

In ESKD patients on chronic dialysis, physical inactivity and mood disturbances might be significantly inter-connected, thereby amplifying their relative impact on quality of life, dysautonomia and long-term outcomes. Future studies on larger populations are recommended to confirm these preliminary observations. Promoting strategies to improve fitness, along with greater attention to physiological aspects, should be incorporated into the clinical management of ESKD patients.

Circulating miRNA 122-5p Expression Predicts Mortality and Cardiovascular Events in Chronic Hemodialysis Patients: A Multicentric, Pilot, Prospective Study

BACKGROUND

Despite patients undergoing chronic hemodialysis (HD) being notoriously prone to adverse cardiovascular (CV) events, risk prediction in this population remains challenging. miRNA 122-5p, a short, non-coding RNA predominantly involved in lipid and carbohydrate metabolism, has recently been related to the onset and progression of CV disease.

METHODS

We run a pilot, multicenter, longitudinal, observational study to evaluate the clinical significance and prognostic usefulness of circulating miRNA 122-5p in a multicentric cohort of 74 individuals on maintenance HD.

RESULTS

Patients displayed lower circulating miRNA 122-5p as compared to healthy controls (p = 0.004). At correlation analyses, ALT (β = 0.333; p = 0.02), E/e' (β = 0.265; p = 0.02) and CRP (β = -0.219; p = 0.041) were independent predictors of miRNA 122-5p levels. During a median follow-up of 22 months (range of 1-24), 30 subjects (40.5%) experienced a composite endpoint of all-cause mortality and fatal/non-fatal CV events. Baseline circulating miRNA 122-5p was higher in these subjects (p = 0.01) and it predicted a significantly higher risk of endpoint occurrence (Kaplan-Meier crude HR 3.192; 95% CI 1.529-6.663; p = 0.002; Cox regression adjusted HR 1.115; 95% CI 1.009-1.232; p = 0.03).

CONCLUSIONS

Altered miRNA 122-5p levels in HD patients may reflect hepatic and CV damage and may impart important prognostic information for improving CV risk prediction in this particular setting.

Hyperkalemia in CKD: an overview of available therapeutic strategies

Hyperkalemia (HK) is a life-threatening condition that often occurs in patients with chronic kidney disease (CKD). High serum potassium (sKsK) is responsible for a higher risk of end-stage renal disease, arrhythmias and mortality. This risk increases in patients that discontinue cardio-nephroprotective renin-angiotensin-aldosterone system inhibitor (RAASi) therapy after developing HK. Hence, the management of HK deserves the attention of the clinician in order to optimize the therapeutic strategies of chronic treatment of HK in the CKD patient. The adoption in clinical practice of the new hypokalaemic agents patiromer and sodium zirconium cyclosilicate (SZC) for the prevention and chronic treatment of HK could allow patients, suffering from heart failure and chronic renal failure, to continue to benefit from RAASi therapy. We have updated a narrative review of the clear variables, correct definition, epidemiology, pathogenesis, etiology and classifications for HK among non-dialysis CKD (ND CKD) patients. Furthermore, by describing the prognostic impact on mortality and on the progression of renal damage, we want to outline the strategies currently available for the control of potassium (K+) plasma levels.

Urinary Marinobufagenin in Patients with Non-Advanced Chronic Kidney Disease: A Cross-Sectional Study

Background and Objectives: The global prevalence of chronic kidney disease (CKD) is on the rise, posing important challenges for healthcare systems. Thus, the search for new factors potentially involved in the pathogenesis, progression and complications of early CKD remains urgent. Marinobufagenin (MBG) is a natriuretic endogenous cardiotonic steroid, and increased circulating levels of it may accelerate kidney damage. In this study, we explored the possible clinical significance of measuring urinary marinobufagenin (uMBG) in patients with non-advanced CKD. Materials and Methods: One hundred and eight adult CKD patients (mean age 71.6 ± 10 years, 70.4% male; mean eGFR 40.54 ± 17 mL/min/1.73 m2) were enrolled in this cross-sectional study. uMBG was measured together with a series of clinical, anthropometric, laboratory and instrumental analyses. Twenty-five healthy matched subjects served as controls for the uMBG measurement. Results: The uMBG values were lower in the patients with CKD as compared to those of the controls (0.37 [IQR: 0.25-0.45] vs. 0.64 [0.46-0.78] nmol/L. p = 0.004), and a significant trend in eGFR levels was noticed across the decreasing uMBG tertiles (p = 0.03). Regarding the correlation analyses, the uMBG values remained robustly associated with the eGFR in multivariate models employing either uMBG or eGFR as the dependent variable (β = 0.248; p = 0.01 and β = 0.139; p = 0.04, respectively). Besides the eGFR, the independent predictors of uMBG values in this population were the use of statins (β = -0.326; p = 0.001), the presence of diabetes (β = 0.243; p = 0.009) and urine sodium (β = 0.204; p = 0.01). Conclusions: Reduced uMBG excretion may reflect impaired renal clearance, which may contribute to the detrimental effects attributed to this hormone due to systemic accumulation. Future studies are needed to clarify the biological mechanisms placing uMBG at the crossroad of sodium intake and the presence of diabetes in CKD-suffering individuals and to verify whether a statin treatment may somewhat limit the detrimental effects of MBG in the presence of impaired renal function.

New Insights on the Role of Marinobufagenin from Bench to Bedside in Cardiovascular and Kidney Diseases

Marinobufagenin (MBG) is a member of the bufadienolide family of compounds, which are natural cardiac glycosides found in a variety of animal species, including man, which have different physiological and biochemical functions but have a common action on the inhibition of the adenosine triphosphatase sodium-potassium pump (Na+/K+-ATPase). MBG acts as an endogenous cardiotonic steroid, and in the last decade, its role as a pathogenic factor in various human diseases has emerged. In this paper, we have collated major evidence regarding the biological characteristics and functions of MBG and its implications in human pathology. This review focused on MBG involvement in chronic kidney disease, including end-stage renal disease, cardiovascular diseases, sex and gender medicine, and its actions on the nervous and immune systems. The role of MBG in pathogenesis and the development of a wide range of pathological conditions indicate that this endogenous peptide could be used in the future as a diagnostic biomarker and/or therapeutic target, opening important avenues of scientific research.

A Rare Complication of Ascariasis: A Case of Acute Interstitial Nephritis

Acute interstitial nephritis (AIN) due to helminths is a rare cause of acute kidney injury (AKI). Helminthiases often progresses insidiously, making diagnosis difficult. This was the case of a 72-year-old man, who presented with renal failure, itching and diarrhoea. Urinalysis revealed leukocyturia, microhaematuria and mild proteinuria. A full blood count revealed leucocytosis with eosinophilia. A stool parasitological examination revealed fertilised eggs of Ascaris lumbricoides. Tubulointerstitial nephropathy secondary to A. lumbricoides infection was suspected. A percutaneous renal biopsy was not performed since the patient refused the anti-platelet therapy discontinuation. Mebendazole, albendazole and prednisone therapy was administered. After worm eradiation and discharge, recovery from the parasitosis, absence of pruritus and eosinophilia, and progressive improvement of renal function were observed, strongly suggesting a causal relationship between Ascaris infection and AIN. Parasite infection should be considered in the differential diagnosis of unexplained renal failure because early diagnosis and treatment are necessary to avoid irreversible complications.

Marinobufagenin, Left Ventricular Hypertrophy and Residual Renal Function in Kidney Transplant Recipients

BACKGROUND

Left ventricular hypertrophy (LVH), which is a pervasive complication of end-stage kidney disease (ESKD), persists in some uremic individuals even after kidney transplantation (Ktx), contributing to worsening CV outcomes. Marinobufagenin (MBG), an endogenous steroid cardiotonic hormone endowed with natriuretic and vasoconstrictive properties, is an acknowledged trigger of uremic cardiomyopathy. However, its clinical significance in the setting of Ktx remains undefined.

METHODS

In a cohort of chronic Ktx recipients (n = 40), we assessed circulating MBG together with a thorough clinical and echocardiographic examination. Forty matched haemodialysis (HD) patients and thirty healthy subjects served as controls for MBG measurements. Patients were then prospectively followed up to 12 months and the occurrence of an established cardio-renal endpoint (death, CV events, renal events, graft rejection) was recorded.

RESULTS

Median MBG plasma levels were lower in Ktx as compared with HD patients (p = 0.02), but higher as compared with healthy controls (p = 0.0005). Urinary sodium (β = 0.423; p = 0.01) and eGFR (β = -0.324; p = 0.02) were the sole independent predictors of MBG in this cohort, while a strong correlation with left ventricular mass index (LVMi), found in univariate analyses (R = 0.543; p = 0.0007), gained significance only in multivariate models not including eGFR. Logistic regression analyses indicated MBG as a significant predictor of the combined endpoint (OR 2.38 [1.10-5.12] per each 1 nmoL/L increase; p = 0.01), as well as eGFR, LVMi, serum phosphate and proteinuria.

CONCLUSIONS

Ktx recipients display altered MBG levels which are influenced by sodium balance, renal impairment and the severity of LVH. Thus, MBG might represent an important missing link between reduced graft function and pathological cardiac remodelling and may hold important prognostic value for improving cardio-renal risk assessment.

A small circulating miRNAs signature predicts mortality and adverse cardiovascular outcomes in chronic hemodialysis patients

Background

Chronic hemodialysis (HD) patients exhibit severe morpho-functional cardiac alterations, posing them at a high risk of death and adverse cardiovascular (CV) outcomes. Despite an unbalanced expression of various microRNAs (miRNAs) has been related to pathological cardiac remodelling and worse CV outcomes, scarce evidence exist on their role in this setting.

Methods

We evaluated circulating levels of a selected miRNAs panel (30a-5p, 23a-3p, 451a and let7d-5p) in 74 chronic HD patients together with a thorough clinical and echocardiography assessment. Individuals were then prospectly followed (median 22 mo.). The primary endpoint was a composite of all-cause and CV mortality and non-fatal CV events.

Results

Circulating levels of all miRNAs were lower in HD patients as compared to healthy controls and independently correlated to the severity of cardiac dysfunction. miRNA 30a-5p, 23a-3p and 451a expression was even lower in 30 subjects (40.5%) reaching the composite endpoint (p&lt;0.001), while no differences were reported for let7d-5p. The predictive value of these miRNAs was supported by univariate followed by multivariate Cox-regression analyses (HR ranging from 0.943 to 0.995; p = 0.05 to 0.02) while Kaplan-Meier analyses confirmed a faster progression to the endpoint in individuals displaying miRNA levels below an optimal ROC-derived cut-off value (p ranging from 0.001 to &lt;0.0001; crude HRs 7.95 to 8.61).

Conclusions

Lower circulating levels of miRNA 30-5p, 23a-3p and 451a in HD patients may reflect cardiac abnormalities and predict a higher risk of worse clinical outcomes in the short-mid term. Future studies on larger HD populations are needed to generalize these findings.

1087 QUANTITATIVE CHANGES IN INTRACARDIAC FLOW PARAMETERS DURING HEMODIALYTIC SESSIONS

Background

Hemodialysis sessions exert an acute impact on cardiac geometry and mechanics. The recent development of quantitative measurement of intracardiac fluid-dynamics offers a new opportinuty to better understand the fine changes in intracardiac cardiac hemodynamics associated with hemodialysis sessions. Our aim was to assess the impact of an hemodialytic session on intracardiac flow dynamics.

Methods

We included 26 consecutive patients on chronic hemodialysis in clinically stable phase. They underwent echocardiography including intracardiac fluid-dynamic analysis by Color Vector Flow Mapping (Hyperdoppler) before and after a single dialysis session. Patients with hemodynamically relevant valvular disease were excluded. A complete fluid-dynamics evaluation included the measurement of multiple parameters such asvortex area (VA); vortex length (VL); vortex depth (VD). Bland Altman Plot has been used to assess intra and inter-observer variability. Changes in fluidodynamics after dialysis sessions were tested using the Wilcoxon matched-pairs test.

Results

Mean Vortex Area (VA) (p=0.034), Vortex Depth (VD) (p=0.024) and Vortex Length (VL) (p=0.037) were significantly reduced after the dialysis session. A similar trend towards the reduction of Direct Flow (DF) parameter after the session was found, which was significantly larger for patients with larger baseline left ventricular (LV) end-diastolic diameter (r=0.446; p=0.037). On the other hand, mean Vortex Intensity (VI) was significanlty increased after dialysis (p=0.046). Among energy parameters, the intradialytic change in Kinetic Energy Fluctuation (KEF) (r=0.4; p=0.058) and Shear Stress Fluctuation (SSF) (r=0.435; p=0.038) were most closely correlated with intradialytic weigth change. Some fluid-dynamic parameters had similar trends of intradialytic change, with stonger correlations among geometric parameters. Delta changes in VA were closely related to changes in VI (p&lt;0.001) or LV (p&lt;0.001). VI was also correlated with VL (p&lt;0.001) and with Kinetc Energy Dissipation (KED) (p=0.030), which was also correlated with VL (p=0.044). KEF was correlated with KED (p=0.001) and SSF (p=0.022). Finally, chenges in SSF were correlated with those in Flow Force Parameter (p=0.033) and Flow Force Angle (p=0.034), that were very closely correlated each other (p&lt;0.001).

Discussion

This is the first study assessing the impact of hemodialytic sessions on intracardiac flow dynamics. Measurement of hyperdoppler indices on hemodialysis chair was feasible and reliable in the whole population. Our results uncovered quantitative chenages of echocardiographic parameters of vortex geometry and energy during hemodialysis.

Acquisition of optical coherence tomography angiography metrics during hemodialysis procedures: A pilot study

BACKGROUND AND AIMS

The observation of optical microcirculation gives us an extraordinary way to directly assess in vivo the responses of human circulation to stress stimuli. We run a pilot study to analyze optical coherence tomography angiography (OCT-A) metrics at determined time-points during a hemodialysis (HD) session to understand how these metrics gradually change and to evaluate possible correlations with patients' characteristics.

METHODS

After the eligibility screening, 15 patients (23 eyes) were included in the study. OCT-A parameters were collected at established time-points: Before treatment (t0), at first hour (t1), at second hour (t2), at third hour (t3), and finally at the end of HD treatment (t4). Patients were finally shared in hypotensive group if they occurred in a hypotensive episode during subsequent month methods or no hypotensive group. The instrument software automatically segmented OCT-A scans into four en-face slabs: The superficial capillary plexus (SCP), the deep capillary plexus (DCP), the outer retinal plexus and the choriocapillaris plexus. In this study we focus on SCP, DCP plexuses.

RESULTS

Overall, the majority of ophthalmic parameters remained unaffected and comparable at dialysis end; a significant reduction being observed at the end vs. starting of HD only for deep capillary plexus (DCP: Whole, fovea, and parafovea) and for central choroid thickness (CCT) (p < 0.05). An overall trend during the session showed in general a decrease with a significance in particular for DCP (whole, fovea, and parafovea) and for CCT (P = 0.006). In the hypotension group, Superficial capillary plexus (SCP: Fovea and parafovea) significantly increased comparing post vs. pre-dialysis values while CCT significantly decreased. Analyzing the trend during treatment only CCT maintained a significant trend (p for trend = 0.002). In the no-hypotension group, neither pre- vs. post-analysis and trend analysis showed a statistical significance.

CONCLUSION

Main achievement of our study was to measure, for the first time in literature, single parameters at different time-points of a HD session. As a result of this process we did not notice a brusque decreasing or increasing of OCT-A metrics but we can characterize the different effect of HD on the two distinct areas distinguishing ocular vessels: Retinal and choroidal circulation. As interesting sub-analysis, Hypotensive group showed for CCT a decreasing trend with a difference statistically significant respect to the group with no-hypotension maintaining a constant trend. In our opinion, these results suggest the role of autonomic system on vessel control in patients affected by uremia.

MO746: Marinobufagenin, Left Ventricular Geometry and Cardiac Dysfunction in End-Stage Kidney Disease Patients

BACKGROUND AND AIMS

Left ventricular hypertrophy (LVH) is remarkably prevalent among end-stage kidney disease (ESKD) on chronic dialysis and has a strong prognostic value for adverse outcomes. In experimental models, the endogenous cardiotonic steroid Marinobufagenin (MBG) promotes cardiac hypertrophy and accelerates uremic cardiomyopathy. In this study, we investigated the possible relationships between MBG, LV geometry and cardiac dysfunction in the clinical setting of ESKD.

METHOD

Plasmatic MBG was measured in 46 prevalent ESKD patients (n = 30 HD, n = 16 PD) together with a thorough laboratory, clinical, bioimpedance and echocardiography assessment. Different patterns of LV geometry were defined by left ventricular mass index (LVMi) and ventricular morphology. Diastolic dysfunction was diagnosed by the ASE/EACVI criteria.

RESULTS

MBG levels were significantly higher in ESKD patients than in healthy controls (0.89 ± 0.45 versus 0.59 ± 0.19 nnmol/L; P = 0.001) and more elevated in PD than in HD (1.09 ± 0.22 versus 0.78 ± 0.55 nnmol/L; P = 0.02). At univariate analysis, MBG was directly correlated with LVMi (R = 0.63; P &lt; 0.001), LAVi (R = 0.57; P &lt; 0.001), E/e’ (R = 0.57; P &lt; 0.001), RAVi (R = 0.42; P = 0.01) and NT-proBNP (R = 0.37; P = 0.01), whereas a significant inverse correlation was observed with extracellular volume at bioimpedance (R=–0.33; P = 0.02). At multivariate analyses, E/e’ (β=0.38; P = 0.009) and LVMi (β = 0.42; P = 0.02) remained the sole independent predictors of MBG. A statistically significant trend in MBG levels (p=0.01) was noticed across different patterns of LV geometry, with the highest values found in eccentric LVH (Fig. 1). MBG levels were higher in the presence of diastolic dysfunction (P = 0.01) and this substance displayed a remarkable diagnostic capacity in distinguish patients with normal LV geometry, LV hypertrophy and, particularly, eccentric LVH (AUC 0.888; P &lt; 0.0001) and diastolic dysfunction (AUC 0.79; p=0.001).

CONCLUSION

Deranged plasma MBG levels in ESKD patients on chronic dialysis may reflect alterations in LV structure and function. MBG may thus candidate as a novel biomarker for improving cardiac assessment in this high-risk population.

MO354: Selenium-Binding Protein 1 (Sepp1) as an Early Sensitive Biomarker of Acute Kidney Injury in Patients Undergoing Cardiopulmonary Bypass

BACKGROUND AND AIMS

Acute kidney injury (AKI) often occurs in patients undergoing major cardiac surgery with cardiopulmonary bypass (CPB). Despite renal ischemia remains the key trigger, sustained oxidative stress is now acknowledged as a significant contributor. Selenium-binding protein 1 (SEPP1) is an intracellular protein whose blood levels increase in response to systemic cardiovascular and oxidative stress, as well as in the course of chronic kidney injury.

METHOD

In this pilot prospective study, we measured circulating SEPP1 levels in a cohort of 45 patients undergoing cardiac surgery with CPB in order to test its possible role in predicting the following occurrence of AKI. Serum samples of SEPP1 were collected before CPB (baseline) and at 4, 8 and 12 h after the end of the procedure and measured with a commercially available ELISA kit.

RESULTS

In the whole cohort, there was a significant statistical trend in SEPP1 levels from baseline to 12 h after CPB [39 (10–45) versus 3263 (1886–5042) ng/mL; P &lt; 0.0001]. Within 48 h from CPB end, 12/45 patients (27%) developed AKI, as defined as an increase in serum creatinine &gt;0.3 mg/dL or an absolute 1.5-fold increase from baseline and/or a reduced urine output (&lt;0.5 mL/kg/h). Circulating SEPP1 displayed an earlier and more prominent increase in AKI patients as compared with others [4 h SEPP1: 52 (39–233) versus 546 (260–1000) ng/mL; P &lt; 0.001]. 8 h SEPP1: 638 (437–1254) versus 1959 (1055–5303) ng/mL; P &lt; 0.001; difference between overall trends: P &lt; 0.001 (Fig. 1). At ROC analyses, either 4 or 8 h circulating SEPP1 had a remarkable diagnostic capacity in identifying AKI patients (AUCs 0.854 and 0.790, both P &lt; 0.001). The crude OR of AKI in patients with 4 and 8 h SEPP1 above the best ROC-derived cut-off values (178 and 1840 ng/mL, respectively) was 22 (95%CI 2.5–192.9) and 14.5 (95% CI 2.9–71.2), respectively. At multivariate analysis, such a risk was independent from potential confounders, including CPB duration, clamping time and age.

CONCLUSION

Increased SEPP1 levels in patients undergoing CPB may reflect a sustained response to systemic oxidative stress. Such a response becomes more prominent when renal damage is also occurring. Studies on larger and more heterogeneous cohorts are needed to confirm whether SEPP1 may be a candidate as an early and specific biomarker of AKI in this high-risk setting.

MO732: Circulating Omentin-1 and Subclinical Atherosclerosis in Chronic Hemodialysis Patients: A Pilot Study

BACKGROUND AND AIMS

Chronic haemodialysis (HD) patients are notoriously at high risk for cardiovascular mortality and morbidity. Omentin-1 (OME-1) is an adipocytokine produced by adipose tissue, whose levels are altered in various dysmetabolic conditions, such as obesity and type 2 diabetes mellitus. Beyond this, nowadays there is evidence indicating that this cytokine plays a crucial role in the genesis and progression of systemic atherosclerosis since it may inhibit plaque formation. With this background in mind, we run a pilot investigation to evaluate the possible correlation between circulating OME-1 levels and mean intimal thickness (IMT) in a small, homogeneous cohort of patients treated by HD (‘HD patients’).

METHOD

From a source cohort of 45 HD patients, we selected 27 individuals suitable to be enrolled. These patients had a dialysis vintage &gt; 6 mo.,  were on a regular 4 h/3 times week HD regimen and had stable clinical conditions. OME-1 levels were measured in their blood by the ELISA together with common laboratory and clinical parameters before starting a mid-week HD session. All the patients then underwent carotid Doppler ultrasound for IMT measurement. A total of 18 healthy subjects were the controls.

RESULTS

In the whole cohort, mean IMT values were 0.75 ± 0.12 mm. However, 8/27 patients (29.6%) presented a pathological IMT (&gt;1 mm). Circulating OME-1 levels in the whole HD cohort were increased as compared with controls [763 (367–1423) versus 371 (228–868) ng/mL; P = 0.03]. However, HD patients with pathological IMT presented, on average, lower OME-1 levels as compared with others [483.25 (168.7–1743) versus 1155 (286–2324); P = 0.05]. In ROC analyses, OME-1 values ≤ 840 ng/mL held an 83.3 sensitivity and 66.7 specificity (AUC 0.716, 95% confidence interval 0.506–0.946) in identifying HD patients with pathological carotid thickening.

CONCLUSION

OME-1 may play a direct role in the atherosclerosis process also in HD patients. Further studies on larger and more heterogeneous HD cohorts are needed to confirm the usefulness of OME-1 plasma levels as potential biomarkers for diagnosing subclinical atherosclerosis and for stratifying the risk of atherosclerosis progression in high-CV risk in HD patients.

MO753: Marinobufagenin Predicts Intradialytic Hypotension Episodes in Prevalent Haemodialysis Patients

BACKGROUND AND AIMS

Intradialytic hypotension (IDH) is a sudden and often dangerous complication of chronic haemodialysis (HD) treatment that may occur in ∼20%–30% of HD sessions. The pathogenesis of IDH is acknowledged to be multifactorial, as it might depend from an impaired vascular refilling capacity, excessive absolute fluid removal, an impaired sympathetic nerve response to volume loss or inadequate peripheral arterial vasoconstriction. This makes the prediction of IDH extremely challenging in the majority of cases.

METHOD

In this pilot, prospective study, we aimed at evaluating the clinical predictors of IDH in a small cohort of prevalent HD patients, with a particular focus on marinobufagenin (MBG), an endogenous cardiotonic steroid whose blood levels have previously been found notably altered in various cardiovascular disorders and body fluid status alterations.

RESULTS

MBG levels in HD patients were significantly higher than in controls (0.75 ± 0.29 versus 0.59 ± 0.19 nnmol/L; P = 0.03), remained unchanged throughout a single HD session and were not correlated with the absolute or partial fluid loss achieved. During a 30-day follow-up, 19 patients (65.5%) experienced at least one IDH (73 total episodes). An inverse correlation was found between baseline MBG and the number of IDH (R = –0.55; P = 0.001). HD patients experiencing IDH presented remarkably lower baseline MBG as compared with others (0.65 ± 0.28 versus 0.94 ± 0.21 nmol/L;  P = 0.008) In these individuals, there was an apparent increase in MBG levels after the first hour of dialysis [0.72 (0.56–1.00) versus 0.65 ± 0.28 nmol/L;  P = 0.04], while such levels progressively decreased throughout the rest of the session, being even more reduced at HD end as compared with baseline [0.45 (0.24–0.95) versus 0.65 ± 0.28 nmol/L;  P = 0.04]. At Kaplan–Meier analyses, HD patients with lower MBG manifested a 4-fold to6-fold increased risk of IDH during follow-up (crude HR ranging from 4.37 to 6.68), depending on the time-point measurement of MBG. At Cox regression analyses, MBG measured at different time points resulted the strongest time-dependent predictor of IDH among all the variables considered (HR ranging from 0.068 to 0.155; P=0.002 to &lt;0.0001).

CONCLUSION

Findings obtained suggest that altered MBG in prevalent HD patients may reflect a diverse vascular and haemodynamic tolerance to HD stress, eventually leading to recurrent IDH episodes. Further studies are needed to confirm the prognostic capacity of MBG for identifying HD patients at high risk of IDH, particularly those with apparently optimal fluid status.

Marinobufagenin, left ventricular geometry and cardiac dysfunction in end-stage kidney disease patients

PURPOSE

Left ventricular hypertrophy (LVH) is remarkably prevalent among end-stage kidney disease (ESKD) on chronic dialysis and has a strong prognostic value for adverse outcomes. In experimental models, the endogenous cardiotonic steroid Marinobufagenin (MBG) promotes cardiac hypertrophy and accelerates uremic cardiomyopathy. In this study, we investigated the possible relationships between MBG, LV geometry and cardiac dysfunction in a clinical setting of ESKD.

METHODS

Plasmatic MBG was measured in 46 prevalent ESKD patients (n = 30 HD, n = 16 PD) together with a thorough laboratory, clinical, bioimpedance and echocardiography assessment. Different patterns of LV geometry were defined by left ventricular mass index (LVMi) and ventricular morphology. Diastolic dysfunction was diagnosed by the ASE/EACVI criteria.

RESULTS

MBG levels were significantly higher in ESKD patients than in healthy controls (p = 0.001) and more elevated in PD than in HD (p = 0.02). At multivariate analyses, E/e' (β = 0.38; p = 0.009) and LVMi (β = 0.42; p = 0.02) remained the sole independent predictors of MBG. A statistically significant trend in MBG levels (p = 0.01) was noticed across different patterns of LV geometry, with the highest values found in eccentric LVH. MBG levels were higher in the presence of diastolic dysfunction (p = 0.01) and this substance displayed a remarkable diagnostic capacity in distinguish patients with normal LV geometry, LV hypertrophy and, particularly, eccentric LVH (AUC 0.888; p < 0.0001) and diastolic dysfunction (AUC 0.79; p = 0.001).

CONCLUSIONS

Deranged plasma MBG levels in ESKD patients on chronic dialysis reflect alterations in LV structure and function. MBG may, thus, candidate as a novel biomarker for improving cardiac assessment in this high-risk population.

Circulating Omentin-1 levels and altered iron balance in chronic haemodialysis patients

Background

Iron deficiency is highly prevalent among patients undergoing chronic haemodialysis (HD) but its correct identification is often problematic as common biomarkers of iron status, such as transferrin saturation (TSAT) and ferritin, can be altered by inflammation or malnutrition.

Methods

In this pilot multicentre study, we aimed at evaluating circulating levels of Omentin-1, a novel fat depot-specific adipokine that is also involved in iron regulation, in a cohort of 85 chronic HD patients with relation to their iron status.

Results

Omentin-1 levels in HD were statistically higher than in healthy controls (P = 0.03) and there was a significant, growing trend in all iron parameters across Omentin-1 tertiles (P < 0.001). Compared with patients with optimal iron status, Omentin-1 levels were lower in subjects categorized according to TSAT ≤20% or serum ferritin ≤200 μg/L (both P < 0.001) and even more reduced in 19 patients (22%) simultaneously displaying low levels of both markers (P < 0.001). In this latter group, Omentin-1 levels increased in parallel to all other iron markers after iron correction by i.v. supplementation. At multivariate regression analyses, ferritin (β = 0.71; P < 0.001) and TSAT (β = 0.32; P = 0.03) remained the sole independent predictors of Omentin-1 levels. This biomarker also showed a remarkable diagnostic capacity at receiver operating characteristic analyses in identifying iron-depleted HD patients according to a criterion of TSAT ≤20% [area under the curve (AUC) 0.827], ferritin ≤200 μg/L (AUC 0.863) or low levels of both parameters (AUC 0.907).

Conclusions

Findings obtained indicate that Omentin-1 is somewhat involved in iron balance regulation and might be a candidate biomarker for diagnosing and managing altered iron conditions in HD patients.

Translational research in nephrology: prognosis

Translational research aims at reducing the gap between the results of studies focused on diagnosis, prognosis and therapy, and every day clinical practice. Prognosis is an essential component of clinical medicine. It aims at estimating the risk of adverse health outcomes in individuals, conditional to their clinical and non-clinical characteristics. There are three fundamental steps in prognostic research: development studies, in which the researcher identifies predictors, assigns the weights to each predictor, and assesses the model’s accuracy through calibration, discrimination and risk reclassification; validation studies, in which investigators test the model’s accuracy in an independent cohort of individuals; and impact studies, in which researchers evaluate whether the use of a prognostic model by clinicians improves their decision-making and patient outcome. This article aims at clarifying how to reduce the disconnection between the promises of prognostic research and the delivery of better individual health.

[Study designs adopted in epidemiology of chronic diseases]

Clinical research is gaining interest among healthcare professionals. This review provides an in-depth analysis of key study designs used in epidemiology, which can help researchers use the right methodology to design and conduct a research project. Case-control studies evaluate the association between an exposure to a specific risk factor and a study endpoint. Cross-sectional studies are indicated to assess the prevalence of a given risk factor. Cohort studies consist of longitudinal studies, in which a population is followed over time. These studies allow to evaluate the association between a risk factor and one or more study endpoints which are absent at the time of the population enrollment. Experimental studies are designed to test the efficacy and safety of an intervention. Generally, they include two groups of individuals who are assigned to either an experimental treatment or a standard treatment, respectively. Meta-analyses are studies that summarize the evidence already published concerning a specific research question and constitute an important source for evidence-based medicine and for the production and updating of guidelines.

Assessment of hypertension in kidney transplantation by ambulatory blood pressure monitoring: a systematic review and meta-analysis

Background

Hypertension (HTN) is common following renal transplantation and it is associated with adverse effects on cardiovascular (CV) and graft health. Ambulatory blood pressure monitoring (ABPM) is the preferred method to characterize blood pressure (BP) status, since HTN misclassification by office BP (OBP) is quite common in this population. We performed a systematic review and meta-analysis aimed at determining the clinical utility of 24-h ABPM and its potential implications for the management of HTN in this population.

Methods

Ovid-MEDLINE and PubMed databases were searched for interventional or observational studies enrolling adult kidney transplant recipients (KTRs) undergoing 24-h ABP readings compared with OBP or home BP. The main outcome was the proportion of KTRs diagnosed with HTN by ABPM, home or OBP recordings. Additionally, day-night BP variability and dipper/non-dipper status were assessed.

Results

Forty-two eligible studies (4115 participants) were reviewed. A cumulative analysis including 27 studies (3481 participants) revealed a prevalence of uncontrolled HTN detected by ABPM of 56% [95% confidence interval (CI) 46-65%]. The pooled prevalence of uncontrolled HTN according to OBP was 47% (95% CI 36-58%) in 25 studies (3261 participants). Very few studies reported on home BP recordings. The average concordance rate between OBP and ABPM measurements in classifying patients as controlled or uncontrolled hypertensive was 66% (95% CI 59-73%). ABPM revealed HTN phenotypes among KTRs. Two pooled analyses of 11 and 10 studies, respectively, revealed an average prevalence of 26% (95% CI 19-33%) for masked HTN (MHT) and 10% (95% CI 6-17%) for white-coat HTN (WCH). The proportion of non-dippers was variable across the 28 studies that analysed dipping status, with an average prevalence of 54% (95% CI 45-63%).

Conclusions

In our systematic review, comparison of OBP versus ABP measurements disclosed a high proportion of MHT, uncontrolled HTN and, to a lesser extent, WCH in KTRs. These results suggest that HTN is not adequately diagnosed and controlled by OBP recordings in this population. Furthermore, the high prevalence of non-dippers confirmed that circadian rhythm is commonly disturbed in KTRs.

Renal denervation for resistant hypertension

BACKGROUND

Resistant hypertension is highly prevalent among the general hypertensive population and the clinical management of this condition remains problematic. Different approaches, including a more intensified antihypertensive therapy, lifestyle modifications or both, have largely failed to improve patients' outcomes and to reduce cardiovascular and renal risk. As renal sympathetic hyperactivity is a major driver of resistant hypertension, in the last decade renal sympathetic ablation (renal denervation) has been proposed as a possible therapeutic alternative to treat this condition.

OBJECTIVES

We sought to evaluate the short- and long-term effects of renal denervation in individuals with resistant hypertension on clinical end points, including fatal and non-fatal cardiovascular events, all-cause mortality, hospital admissions, quality of life, blood pressure control, left ventricular hypertrophy, cardiovascular and metabolic profile and kidney function, as well as the potential adverse events related to the procedure.

SEARCH METHODS

For this updated review, the Cochrane Hypertension Information Specialist searched the following databases for randomised controlled trials up to 3 November 2020: Cochrane Hypertension's Specialised Register, CENTRAL (2020, Issue 11), Ovid MEDLINE, and Ovid Embase. The World Health Organization International Clinical Trials Registry Platform (via CENTRAL) and the US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov were searched for ongoing trials. We also contacted authors of relevant papers regarding further published and unpublished work. The searches had no language restrictions.

SELECTION CRITERIA

We considered randomised controlled trials (RCTs) that compared renal denervation to standard therapy or sham procedure to treat resistant hypertension, without language restriction.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed study risk of bias. We summarised treatment effects on available clinical outcomes and adverse events using random-effects meta-analyses. We assessed heterogeneity in estimated treatment effects using Chi² and I² statistics. We calculated summary treatment estimates as a mean difference (MD) or standardised mean difference (SMD) for continuous outcomes, and a risk ratio (RR) for dichotomous outcomes, together with their 95% confidence intervals (CI). Certainty of evidence has been assessed using the GRADE approach.

MAIN RESULTS

We found 15 eligible studies (1416 participants). In four studies, renal denervation was compared to sham procedure; in the remaining studies, renal denervation was tested against standard or intensified antihypertensive therapy. Most studies had unclear or high risk of bias for allocation concealment and blinding.  When compared to control, there was low-certainty evidence that renal denervation had little or no effect on the risk of myocardial infarction (4 studies, 742 participants; RR 1.31, 95% CI 0.45 to 3.84), ischaemic stroke (5 studies, 892 participants; RR 0.98, 95% CI 0.33 to 2.95), unstable angina (3 studies, 270 participants; RR 0.51, 95% CI 0.09 to 2.89) or hospitalisation (3 studies, 743 participants; RR 1.24, 95% CI 0.50 to 3.11). Based on moderate-certainty evidence, renal denervation may reduce 24-hour ambulatory blood pressure monitoring (ABPM) systolic BP (9 studies, 1045 participants; MD -5.29 mmHg, 95% CI -10.46 to -0.13), ABPM diastolic BP (8 studies, 1004 participants; MD -3.75 mmHg, 95% CI -7.10 to -0.39) and office diastolic BP (8 studies, 1049 participants; MD -4.61 mmHg, 95% CI -8.23 to -0.99). Conversely, this procedure had little or no effect on office systolic BP (10 studies, 1090 participants; MD -5.92 mmHg, 95% CI -12.94 to 1.10). Moderate-certainty evidence suggested that renal denervation may not reduce serum creatinine (5 studies, 721 participants, MD 0.03 mg/dL, 95% CI -0.06 to 0.13) and may not increase the estimated glomerular filtration rate (eGFR) or creatinine clearance (6 studies, 822 participants; MD -2.56 mL/min, 95% CI -7.53 to 2.42).  AUTHORS' CONCLUSIONS: In patients with resistant hypertension, there is low-certainty evidence that renal denervation does not improve major cardiovascular outomes and renal function. Conversely, moderate-certainty evidence exists that it may improve 24h ABPM and diastolic office-measured BP. Future trials measuring patient-centred instead of surrogate outcomes, with longer follow-up periods, larger sample size and more standardised procedural methods are necessary to clarify the utility of this procedure in this population.

Management of obesity in kidney transplant candidates and recipients: A clinical practice guideline by the Descartes working group of ERA

The clinical practice guideline Management of Obesity in Kidney Transplant Candidates and Recipients was developed to guide decision-making in caring for people with end-stage kidney disease (ESKD) living with obesity. The document considers the challenges in defining obesity, weighs interventions for treating obesity in kidney transplant candidates as well as recipients and reflects on the impact of obesity on the likelihood of wait-listing as well as its effect on transplant outcomes. It was designed to inform management decisions related to this topic and provide the backdrop for shared decision-making. This guideline was developed by the European Renal Association’s Developing Education Science and Care for Renal Transplantation in European States working group. The group was supplemented with selected methodologists to supervise the project and provide methodological expertise in guideline development throughout the process. The guideline targets any healthcare professional treating or caring for people with ESKD being considered for kidney transplantation or having received a donor kidney. This includes nephrologists, transplant physicians, transplant surgeons, general practitioners, dialysis and transplant nurses. Development of this guideline followed an explicit process of evidence review. Treatment approaches and guideline recommendations are based on systematic reviews of relevant studies and appraisal of the quality of the evidence and the strength of recommendations followed the Grading of Recommendations Assessment, Development and Evaluation approach. Limitations of the evidence are discussed and areas of future research are presented.

Retarding Progression of Chronic Kidney Disease in Autosomal Dominant Polycystic Kidney Disease with Metformin and Other Therapies: An Update of New Insights

Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent single-gene disorder leading to renal failure. Current therapies are aimed to treat renal and extrarenal complications of ADPKD, but improved knowledge of the pathophysiological mechanisms leading to the generation and growth of cysts has permitted the identification of new drug candidates for clinical trials. Among these, in this review, we will examine above all the role of metformin, hypothesized to be able to activate the AMP-activated protein kinase (AMPK) pathway and potentially modulate some mechanisms implicated in the onset and the growth of the cysts.

Autosomic dominant polycystic kidney disease and metformin: Old knowledge and new insights on retarding progression of chronic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is the most common congenital kidney disorder, generally caused by mutations in the PKD1 and PKD2 genes, coding for polycystins 1 and 2. Its pathogenesis is accompanied by alterations of the cAMP, mTOR, MAPK/ERK, and JAK/STAT pathways. ADPKD is clinically characterized by the formation of many growing cysts with kidney enlargement and a progressive damage to the parenchyma, up to its complete loss of function, and the onset of end-stage renal disease (ESRD). The current aim of ADPKD therapy is the inhibition of cyst development and retardation of chronic kidney disease progression. Several drugs have been recently included as potential therapies for ADPKD including metformin, the drug of choice for the treatment of type 2 diabetes mellitus, according to its potential inhibitory effects on cystogenesis. In this review, we summarize preclinical and clinical evidence endorsing or rejecting metformin administration in ADPKD evolution and pathological mechanisms. We explored the biology of APDKD and the role of metformin in slowing down cystogenesis searching PubMed and Clinical Trials to identify relevant data from the database inception to December 2020. From our research analysis, evidence for metformin as emerging cure for ADPKD mainly arise from preclinical studies. In fact, clinical studies are still scanty and stronger evidence is awaited. Its effects are likely mediated by inhibition of the ERK pathway and increase of AMPK levels, which are both linked to ADPKD pathogenesis.

Smoking habit as a risk amplifier in chronic kidney disease patients

Several studies showed the association between non-traditional risk factors [proteinuria and estimated Glomerular Filtration Rate (eGFR)] and cardiovascular (CV) and renal outcomes. Nevertheless, the etiologic role of traditional CV risk factors in referred CKD patients is less defined. Herein, we examined the association between smoking habit and CV events, mortality and CKD progression. We undertook an observational analysis of 1306 stage III–V CKD patients. Smoking habit was modeled as a categorical (never, current or former smokers) and continuous (number of cigarettes/day) variable. Mean eGFR was 35.8 ± 12.5 mL/min/1.73 m². Never, current and former smokers were 61.1%, 10.8% and 28.1%. During a median follow-up of 2.87 years, current and former smokers were at significant risk for CV events (HRs of 1.93 [95% CI, 1.18–3.16] and 1.44 [95% CI, 1.01–2.05]) versus never smokers. Current smokers were at increased mortality risk (HR 2.13 [95% CI, 1.10–4.11]). Interactions were found between former smokers and proteinuria (p = 0.007) and diabetes (p = 0.041) for renal risk, and between current smokers and male gender (p = 0.044) and CKD stage V (p = 0.039) for renal and mortality risk. In referred CKD patients, smoking habit is independently associated with CV events and mortality. It acts as a risk “amplifier” for the association between other risk factors and renal outcomes.

Nephrosclerosis impacts time trajectory of renal function and outcomes in elderly individuals with chronic kidney disease

Despite hypertension ranks among the leading causes of chronic kidney disease (CKD), the impact of chronic hypertensive nephropathy, the so-called 'nephrosclerosis' (NS), on CKD progression is often unpredictable, particularly in elderly population. We have conducted a prospective, observational study to define renal function patterns and outcomes in elderly CKD individuals with or without NS. Three hundred four individuals with an already established CKD were categorized according to the etiology of CKD. NS was defined as the presence of CKD associated with long-term essential hypertension, hypertensive retinopathy, left ventricular hypertrophy and minimal proteinuria. Time trajectories in estimated glomerular filtration rate (eGFR) (CKD-Epi) were computed over a 4-year follow-up. In addition, we analyzed the occurrence of a composite outcome of doubling of serum creatinine levels, eGFR reduction ≥25% and/or the need of chronic renal replacement therapy. CKD was secondary to nephrosclerosis (CKD-NS) in 220 (72.3%). In the whole cohort, the average estimated annual GFR slope was 1.8 mL/min/1.73 m² eGFR decline was slower in CKD-NS as compared with others (1.4 vs 3.4 mL/min/1.73 m²; p<0.001). The composite renal outcome during follow-up occurred less frequently among elderly with CKD-NS (16/204 vs 14/70; p=0.01, crude HR 0.43, 95% CI 0.22 to 0.85) and was associated at logistic analyses with the etiology of CKD, background cardiovascular disease, total and low density lipoproteins (LDL) cholesterol, and glycemia levels (p value was ranging from 0.01 to 0.05). Despite being highly prevalent in the elderly, NS is associated with a more favorable renal disease course as compared with other conditions.

MO291RITUXIMAB IS EFFECTIVE AND SAFE IN ADULTS WITH STEROID-DEPENDENT NEPHROTIC SYNDROME: A LONG-TERM, SINGLE-CENTER EXPERIENCE

Background and Aims

Steroid-dependent nephrotic syndrome (SDNS) may require a prolonged multi-drug therapy with risk of drug toxicity and renal failure. Rituximab (RTX) treatment has been found to be helpful in reducing the steroid dosage and the need for immunosuppressants (ISs), but little data are currently available regarding very long-term outcomes in adults. We herein describe a long-term, single-center experience of RTX use in a large series of adults with SDNS.

Method

We studied 23 adult patients with SDNS (mean age 54.2±17.1 y; 65% male; BMI 28.5±4.7), mostly consequent to membranous (47.8%) or focal glomerulonephritis (30.2 %) who were eligible to start a RTX regimen. Before entering the RTX protocol, proteinuria and eGFR were 7.06±3.87 g/24h and 65.9±28.2 ml/min/1.73 m2, respectively; albumin and CD19/CD20 ratio were 2.9±0.9 g/L and 0.99±0.01 respectively; the mean number of ISs was 2.39±0.89 and the mean annual rate of relapses was 2.2±0.9.

Results

Patients were followed over a mean follow-up of 64 months (range: 12-144). After RTX (mean dose: 1202.1±372.4 mg) the rate of relapses was virtually nullified (p&lt;0.001). eGFR remained roughly stable (62.1±19.8 ml/min/1.73 m2, p=NS), while proteinuria, albumin, CD19/CD20 and BMI all significantly improved (p ranging from 0.01 to 0.001). The mean number of additional ISs was also reduced (0.44±0.12; p&lt;0.001) and RTX enabled discontinuation of steroids in 13/23 (56.5%) patients. No major adverse events related to therapy were recorded.

Conclusion

Findings from this large case-series with a remarkable very long follow-up reinforce the role of RTX as an efficient and safe weapon to improve outcomes in adult patients suffering from SDNS.

MO413EFFECTS OF CHRONIC, LONG-TERM ACE-INHIBITOR TREATMENT ON CYTOKINE STORM AND RENAL FUNCTION AFTER CARDIO-PULMONARY BYPASS: A PROSPECTIVE OBSERVATIONAL STUDY

Background and Aims

Cardiopulmonary bypass (CPB) may trigger organs damage, including kidney injury, due to a massive cytokine release. In this observational, prospective study, we have analyzed the possible impact of chronic treatment with ACE-Inhibitors (ACE-I) on the inflammatory response and renal function after CPB.

Method

Sixty-nine patients undergoing major cardiac surgery with CPB were enrolled. Patients were stratified according to long-term (&gt;6 mo.) ACE-I use (n=38) or not (n=31). The primary endpoint was to analyze the changes in their IL-1 alpha, IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, TNF alpha, EGF and VEGF plasma levels. Secondary (renal) endpoints were: postoperative acute kidney injury (AKI), recovery of baseline GFR values and the absolute changes in renal function indexes.

Results

After CPB, IL-1alpha, IL-1beta, IL-4 and TNF-alpha remained stable overtime, while a significant decrease in IL-2 plasma levels was noticed in the ACE-I group (p=0.01). IL-6 and IL-8 plasma levels increased after surgery and tended to decrease after 48h. IL-10 plasma levels showed a similar variation, but both their rise and decrease were more pronounced in patients under ACE-I treatment (p=0.007). Finally, VEGF and EGF showed a marked initial decrease with a tendency to normalization 10 days after surgery (p for trend ranging from 0.01 to 0.001) (Figure 1-2).

The occurrence of AKI within 2 days after surgery, the rate of GFR recovery and the absolute changes in renal function indexes were not statistically different between groups (Figure 3).

Conclusion

Chronic, long-term ACE-I treatment may influence the inflammatory response following CPB. On the other hand, this drug class apparently has neutral impact on perioperative renal outcomes.

MO728OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY (OCT-A) METRICS PREDICT INTRADIALYTIC HYPOTENSION EPISODES IN CHRONIC HEMODIALYSIS PATIENTS: A PILOT, PROSPECTIVE STUDY

Background and Aims

In chronic hemodialysis (HD) patients, intradialytic hypotension (IDH) is a complication that increases mortality risk. The pathogenesis of this condition remains partly unexplained although dysfunctions of the nervous autonomous system and various factors related to the hemodialytic procedure like rapid or excessive ultrafiltration, excessive reduction in osmolality and reaction to the dialyzer membrane or machine tubing, seem to play a key role. The observation of ocular microcirculation gives us an exceptional chance to directly evaluate in vivo the reactions of human circulation to stress stimuli. Indeed, the ocular microcirculation is involved in systemic disease and early changes in vascular structures may predict the development of systemic vascular disorders. We run a pilot study to analyzing possible relationships between optical coherence tomography angiography (OCT-A) metrics and IDH and to evaluate whether OCT-A could represent a useful tool to stratify the hypotensive risk in dialysis patients.

Method

a total of 35 eyes (35 patients) being correctly analyzed. OCT-A was performed before and after a single dialysis session. Patients were then followed up to 30 days (10 HD sessions) and a total of 73 IDHs were recorded with 12 patients (60%) experiencing at least one IDH.

Results

Central choroid thickness (CCT), 6x6 mm whole vessel density (VD) of superficial capillary plexus (SPC) and 6x6 mm foveal VD of deep capillary plexus (DCP) were reduced after dialysis (Figure 1). At logistic regression analysis, IDH was positively associated with baseline foveal VD of SCP and DCP, while an inverse association was found with the choroid (Figure 2). In Kaplan-Meier analyses of patients categorized according to the ROC-derived optimal thresholds, CCT, the 3x3 foveal VD of SCP, the 3x3 mm and 6x6 mm foveal VD of DCP and the 6x6 mm foveal VD of SCP were strongly associated with a higher risk of IDH over the 30-days follow-up.

Conclusion

In our study, we demonstrated that HD patients experiencing frequent IDH episodes showed a different ocular pattern with respect to those not facing with this complication. Furthermore, a simple measurement of retinal and choroid parameters by OCT-A before a single dialysis session may help predicting the risk of following IDH in the short-term. In HD patients, a single OCT-A measurement may represent a non-invasive, rapid tool to evaluate the compliance of vascular bed to HD stress and to stratify the risk of IDH in the short term.

MO791HIGH-SENSITIVITY CARDIAC TROPONIN I CORRELATES WITH THE CARDIAC DYSFUNCTION AND WITH THE SEVERITY OF ANEMIA IN DIALYSIS PATIENTS

Background and Aims

Several evidences demonstrate that chronic dialysis treatment alters troponin levels, even in the absence of an acute myocardial event, although the underlying causes remain largely unclear. In this small pilot study, we aimed at analyzing high sensitivity troponin T (HsTnT) in a cohort of dialysis patients to identify the potential clinical predictors.

Method

HsTnT levels were measured together with common laboratory and clinical parameters in 39 chronic dialysis patients (middle age: 65±12 aa; 82% M; 30 in hemodialysis and 9 in peritoneal dialysis). The patients underwent also a complete echocardiography assessment.

Results

HsTnT levels were higher than normal reference values (median 46.1 ng/L IQR 33.5-84.3),but showing no differences between hemodialysis and peritoneal dialysis patients (p=0.19). At correlation analyses, HsTnT were strongly associated with beta2-MCG (R=0.43; p=0.008), Hemoglobin (r=-0.47; p=0.002) and, in particular, with some echocardiography parameters such as ejection fraction (R=-0.29; p=0.05), E/E’ratio (R=0.56; p=0.006) and LAVI (R=0.41; p=0.05) Figure 1.

Conclusion

In a small cohort of dialysis patients, high HsTnt levels were at the crossroad between the severity of functional heart dysfunction and anemia. Larger studies are advocated to further clarify the role of HsTnT as a potential biomarker reflecting the anemic cardiorenal syndrome which characterizes uremic subjects.

MO911ALTERED CIRCULATING OMENTIN-1 LEVELS REFLECT IRON DEFICIENCY IN CHRONIC HEMODIALYSIS PATIENTS

Background and Aims

Iron deficiency is pervasive among hemodialysis (HD) patients; however, although transferrin saturation (TSAT) of &lt;20% and/or serum ferritin of &lt;200 ng/mL should express iron scarcity, in HD patients high ferritin levels could be related to inflammation rather than reflecting optimal iron stores. Omentin-1 is an anti-inflammatory adipokine that is also involved in regulation of iron metabolism through binding with lactoferrin. In this pilot study, we aimed at evaluating serum levels of Omentin-1 in a small HD population, in order to determine its possible relationships with iron status.

Method

Omentin-1 was measured by ELISA in serum samples of 33 chronic HD patients before a single mid-week HD session and at 1h, 2h and 3h after dialysis start. Common biochemical and clinical parameters were also recorded.

Results

Serum omentin-1 levels were statistically higher in HD patients than in matched healthy controls (763 [367-1423] vs. 371 [228-868] ng/mL; p=0.03). Omentin-1 levels were broken down after the first hour of HD (reduction ratio: 45±5%) and tended to get back to baseline after the third hour (p=0.04). Correlation analyses showed omentin-1 levels to be directly associated with serum iron (R=0.380; p=0.03), ferritin (R=0.843; p&lt;0.001), TSAT (R=0.661; p&lt;0.001), serum amylase (R=0.454; p=0.01), ALT (R=0.380; p=0.03) and inversely with serum phosphate (R=-0.403; p=0.02), troponin (R=-0.443; p=0.01) and transferrin (R=-0.390;p=0.04). At ROC analyses, Omentin-1 levels showed a remarkable capacity to discriminate HD patients with iron deficiency (TSAT&lt;20%) with an AUC of 0.830 (95%CI 0.658 to 1.000; p=0.002. best cut-off value: ≤478.8 ng/mL; sens. 75%; spec. 85%). Of note, such discriminatory capacity was even better than that of serum ferritin (AUC 0.739; 95%CI 0.528 to 0.950; p for differences between AUCs=0.04; Figure 1)

Conclusion

Findings from this pilot study demonstrate that HD patients have altered Omentin-1 values probably because this protein is involved in the maintenance of iron equilibrium. Larger studies are needed to confirm whether Omentin-1 might be proposed as a new tool in the assessment of iron deficiency and in the management of iron therapy for HD patients.

MO462TIME-TRAJECTORIES OF RENAL FUNCTION AND OUTCOMES IN ELDERLY INDIVIDUALS WITH CKD OF VARIOUS ETIOLOGY

Background and Aims

Despite hypertension ranks among the leading causes of chronic kidney disease (CKD), the impact of chronic hypertensive nephropathy, the so-called “nephrosclerosis” (NS), on CKD progression towards end-stage kidney disease (ESKD) is often unpredictable, particularly in older populations. We run a prospective, observational study to define renal function patterns and outcomes in elderly individuals with or without NS-related CKD.

Method

304 elderly patients with already established CKD (mean age 69±4 y; mean eGFR 44.2±19.6 mL/min/1.73 m2; male= 64.1%), followed in our outpatients’ clinic were categorized according to the etiology of CKD. NS was defined as the presence of CKD associated with long-term essential hypertension, hypertensive retinopathy, left ventricular hypertrophy and minimal proteinuria. Time-trajectories in eGFR (CKD-Epi) were computed over a 4-year follow-up. In addition, we analysed the occurrence of a composite outcome of doubling of serum creatinine, eGFR reduction≥ 25% and/or ESKD needing dialysis or kidney transplantation.

Results

CKD was secondary to nephrosclerosis (CKD-NS) in 220 (72.3%) patients. Among the remaining 84 (27.7%), glomerular/diabetic diseases were the most frequent cause of CKD (47.6%). In the whole cohort, the average estimated annual GFR slope was of 1.8 mL/min/1.73 m2. eGFR decline was slower in CKD-NS as compared with the one of others (1.4 vs. 3.4 mL/min/1.73 m2; p&lt;0.001. Figure 1). The composite renal outcome during follow-up (median 36 mo.; range 6-48) occurred less frequently among elderly with CKD-NS (16/204 vs 14/70; p=0.01 Crude HR 0.43, 95%CI 0.22-0.85) and was associated at logistic analyses with etiology of CKD, serum total cholesterol, serum LDL cholesterol levels and glycemia (p ranging from 0.01 to 0.04).

Conclusion

Despite being highly prevalent in the elderly, NS is associated with a more favorable renal disease course as compared with other conditions. Therapeutic efforts to delay CKD progression in older populations should go beyond just optimizing blood pressure control and focus more on concomitant diseases.

Serum gamma-glutamyltransferase, oxidized LDL and mortality in the elderly

BACKGROUND

Serum gamma-glutamyltransferase (GGT) is a liver enzyme involved in the metabolism of glutathione (GSH), a major antioxidant in humans. GGT is a risk factor for mortality in young and middle-aged individuals but this association has been poorly investigated in the elderly.

METHODS

We studied the relationship between GGT and all-cause mortality and tested whether oxidized low-density lipoproteins (oxLDL) modify this association in a cohort of 1038 elderly individuals.

RESULTS

During the observation time (median 9 years), 401 individuals died. In a Cox regression model adjusting for potential confounders, GGT was an independent risk factor for all-cause mortality [HR (20U/L increase in serum GGT): 1.11, 95% CI 1.02-1.21, P = 0.02]. Furthermore, increasing levels of oxLDL amplified the risk excess for all-cause mortality associated with GGT (P for the effect modification = 0.003).

CONCLUSIONS

In the elderly, serum GGT is an independent risk factor for all-cause mortality and circulating oxLDL amplify the magnitude of this association.

Blood pressure monitoring in kidney transplantation: a systematic review on hypertension and target organ damage

BACKGROUND

Sparse studies show that ambulatory blood pressure monitoring (ABPM) is superior to office BP (oBP) measurements to predict target organ damage and cardiovascular (CV) events in kidney transplant recipients (KTRs). We performed a systematic review aimed at determining the potential associations between BP recordings by different methods and renal and CV outcomes in this population.

METHODS

Major medical databases were searched for studies enrolling adult KTRs undergoing 24h ABPM compared to office or home BP measurements. Main outcomes were: associations between different BP recordings and renal and CV outcomes. Additionally, any association between the circadian BP pattern (dipping/non-dipping status) and outcomes was assessed.

RESULTS

Twenty-two studies (2078 participants) were reviewed. Amongst 12 studies collecting data on renal endpoints, ten studies found that BP assessed by ABPM was a stronger predictor of renal function decline, assessed by serum creatinine (SCr) and/or creatinine clearance (CrCl) or estimated glomerular filtration rate (eGFR), than traditional office measurements. Twelve studies analyzed the relation between different BP recordings and CV target organ damages and reported robust correlations between echocardiographic abnormalities [i.e. left ventricular mass index (LVM/LVMI)] and 24h ABPM, but not with office BPs. Furthermore, 24h ABPM correlated better than oBP with markers of vascular damage, such as carotid intima-media thickness (IMT), diffuse thickening, and endothelial dysfunction. Additionally, abnormal circadian BP pattern (non-dippers and reverse dippers) identified a group of kidney recipients at risk for kidney function loss and CV abnormalities.

CONCLUSIONS

In our systematic review, ABPM reflected target organ damage more closely than oBP in KTRs. Furthermore, altered circadian BP profile associated with renal and CV target organ damages.

Utility of Blood Flow/Resistance Index Ratio (Qx) as a Marker of Stenosis and Future Thrombotic Events in Native Arteriovenous Fistulas

Objective: The resistance index (RI) and the blood flow volume (Q_a) are the most used Doppler ultrasound (DUS) parameters to identify the presence of stenosis in arteriovenous fistula (AVF). However, the reliability of these indexes is now matter of concern, particularly in predicting subsequent thrombosis. In this study, we aimed at testing the diagnostic capacity of the Q_a/RI ratio (Q_x) for the early identification of AVF stenosis and for thrombosis risk stratification.

Methods: From a multicentre source population of 336 HD patients, we identified 119 patients presenting at least one “alarm sign” for clinical suspicious of stenosis. Patients were therefore categorized by DUS as stenotic (n = 60) or not-stenotic (n = 59) and prospectively followed. Q_a, RI, and Q_X, together with various clinical and laboratory parameters, were recorded.

Results: Q_a and Q_x were significantly higher while RI was significantly lower in non-stenotic vs. stenotic patients (p < 0.001 for each comparison). At ROC analyses, Q_x had the best discriminatory power in identifying the presence of stenosis as compared to Q_a and RI (AUCs 0.976 vs. 0.953 and 0.804; p = 0.037 and p < 0.0001, respectively). During follow-up, we registered 30 thrombotic events with an incidence rate of 12.65 (95% CI 8.54–18.06) per 100 patients/year. In Cox-regression proportional hazard models, Q_x showed a better capacity to predict thrombosis occurrence as compared to Q_a (difference between c-indexes: 0.012; 95% CI 0.004–0.01).

Conclusions: In chronic haemodialysis patients, Q_x might represent a more reliable and valid indicator for the early identification of stenotic AVFs and for predicting the risk of following thrombosis.

Antecedent ACE-inhibition, inflammatory response, and cardiac surgery associated acute kidney injury

Cardiopulmonary bypass (CPB) may trigger organs damage, including kidney injury, due to a massive cytokine release. In this observational, prospective study, we analyzed the possible impact of chronic treatment with ACE-Inhibitors (ACE-I) on the inflammatory response and renal function after CPB. Sixty-nine patients undergoing major cardiac surgery with CPB were enrolled. Patients were stratified according to long-term (> 6 mo.) ACE-I use (n = 38) or not (n = 31). The primary endpoint was the change in IL-1alpha, IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, TNF alpha, EGF and VEGF plasma levels. Secondary (renal) endpoints were postoperative acute kidney injury (AKI), recovery of baseline GFR values and the absolute changes in renal function indexes. After CPB, IL-1alpha, IL-1beta, IL-4 and TNF-alpha remained stable over time while a significant decrease in IL-2 levels was noticed in the ACE-I group (p = 0.01). IL-6 and IL-8 increased after surgery and tended to decrease after 48 h. IL-10 levels showed a similar variation, but both their rise and decrease were more pronounced in patients under ACE-I treatment (p = 0.007). Finally, VEGF and EGF showed a marked initial decrease with a tendency to normalization 10 days after surgery (p for trend ranging from 0.01 to 0.001). The occurrence of AKI within 2 days after surgery, the rate of GFR recovery and the absolute changes in renal function indexes were not statistically different between groups. Chronic, long-term ACE-I treatment may influence the inflammatory response following CPB. On the other hand, this drug class apparently has neutral impact on perioperative renal outcomes.

Aldosterone antagonists in addition to renin angiotensin system antagonists for preventing the progression of chronic kidney disease

BACKGROUND

Treatment with angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB) is used to reduce proteinuria and retard the progression of chronic kidney disease (CKD). However, resolution of proteinuria may be incomplete with these therapies and the addition of an aldosterone antagonist may be added to further prevent progression of CKD. This is an update of a Cochrane review first published in 2009 and updated in 2014.

OBJECTIVES

To evaluate the effects of aldosterone antagonists (selective (eplerenone), non-selective (spironolactone or canrenone), or non-steroidal mineralocorticoid antagonists (finerenone)) in adults who have CKD with proteinuria (nephrotic and non-nephrotic range) on: patient-centred endpoints including kidney failure (previously know as end-stage kidney disease (ESKD)), major cardiovascular events, and death (any cause); kidney function (proteinuria, estimated glomerular filtration rate (eGFR), and doubling of serum creatinine); blood pressure; and adverse events (including hyperkalaemia, acute kidney injury, and gynaecomastia).

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 13 January 2020 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs that compared aldosterone antagonists in combination with ACEi or ARB (or both) to other anti-hypertensive strategies or placebo in participants with proteinuric CKD.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Data were summarised using random effects meta-analysis. We expressed summary treatment estimates as a risk ratio (RR) for dichotomous outcomes and mean difference (MD) for continuous outcomes, or standardised mean difference (SMD) when different scales were used together with their 95% confidence interval (CI). Risk of bias were assessed using the Cochrane tool. Evidence certainty was evaluated using GRADE.

MAIN RESULTS

Forty-four studies (5745 participants) were included. Risk of bias in the evaluated methodological domains were unclear or high risk in most studies. Adequate random sequence generation was present in 12 studies, allocation concealment in five studies, blinding of participant and investigators in 18 studies, blinding of outcome assessment in 15 studies, and complete outcome reporting in 24 studies. All studies comparing aldosterone antagonists to placebo or standard care were used in addition to an ACEi or ARB (or both). None of the studies were powered to detect differences in patient-level outcomes including kidney failure, major cardiovascular events or death. Aldosterone antagonists had uncertain effects on kidney failure (2 studies, 84 participants: RR 3.00, 95% CI 0.33 to 27.65, I² = 0%; very low certainty evidence), death (3 studies, 421 participants: RR 0.58, 95% CI 0.10 to 3.50, I² = 0%; low certainty evidence), and cardiovascular events (3 studies, 1067 participants: RR 0.95, 95% CI 0.26 to 3.56; I² = 42%; low certainty evidence) compared to placebo or standard care. Aldosterone antagonists may reduce protein excretion (14 studies, 1193 participants: SMD -0.51, 95% CI -0.82 to -0.20, I² = 82%; very low certainty evidence), eGFR (13 studies, 1165 participants, MD -3.00 mL/min/1.73 m², 95% CI -5.51 to -0.49, I² = 0%, low certainty evidence) and systolic blood pressure (14 studies, 911 participants: MD -4.98 mmHg, 95% CI -8.22 to -1.75, I² = 87%; very low certainty evidence) compared to placebo or standard care. Aldosterone antagonists probably increase the risk of hyperkalaemia (17 studies, 3001 participants: RR 2.17, 95% CI 1.47 to 3.22, I² = 0%; moderate certainty evidence), acute kidney injury (5 studies, 1446 participants: RR 2.04, 95% CI 1.05 to 3.97, I² = 0%; moderate certainty evidence), and gynaecomastia (4 studies, 281 participants: RR 5.14, 95% CI 1.14 to 23.23, I² = 0%; moderate certainty evidence) compared to placebo or standard care. Non-selective aldosterone antagonists plus ACEi or ARB had uncertain effects on protein excretion (2 studies, 139 participants: SMD -1.59, 95% CI -3.80 to 0.62, I² = 93%; very low certainty evidence) but may increase serum potassium (2 studies, 121 participants: MD 0.31 mEq/L, 95% CI 0.17 to 0.45, I² = 0%; low certainty evidence) compared to diuretics plus ACEi or ARB. Selective aldosterone antagonists may increase the risk of hyperkalaemia (2 studies, 500 participants: RR 1.62, 95% CI 0.66 to 3.95, I² = 0%; low certainty evidence) compared ACEi or ARB (or both). There were insufficient studies to perform meta-analyses for the comparison between non-selective aldosterone antagonists and calcium channel blockers, selective aldosterone antagonists plus ACEi or ARB (or both) and nitrate plus ACEi or ARB (or both), and non-steroidal mineralocorticoid antagonists and selective aldosterone antagonists.

AUTHORS' CONCLUSIONS

The effects of aldosterone antagonists when added to ACEi or ARB (or both) on the risks of death, major cardiovascular events, and kidney failure in people with proteinuric CKD are uncertain. Aldosterone antagonists may reduce proteinuria, eGFR, and systolic blood pressure in adults who have mild to moderate CKD but may increase the risk of hyperkalaemia, acute kidney injury and gynaecomastia when added to ACEi and/or ARB.

COVID-19 clinical manifestations and treatment strategies among solid-organ recipients: A systematic review of cases

BACKGROUND

COVID-19 has been spreading worldwide with a significant death toll. Solid-organ transplantation (SOT) recipients are at higher risk due to their suppressed immune system. In this study, we aimed to conduct a systematic review on COVID-19 clinical manifestations and treatment strategies in SOT recipients.

METHODS

We searched three databases for relevant terms related to COVID-19 and transplantation. 50 studies, including 337 patients, were reviewed.

RESULTS

Two hundred thirty six patients were male, with a mean age of 49.9 years. The most prevalent group was the kidney 57.0%, followed by 17.2% heart and 13.6% liver. Fever and cough were the most reported clinical presentations. Infiltration (55.4%) in chest x-ray and ground-glass opacity (67.1%) in CT scans were the most radiological findings. It was found that 96.8% and 72.4% of patients present with CRP level and lymphocytopenia, respectively, and 70.6% of kidney recipients patients presented with high creatinine levels. The most common baseline immunosuppressants were calcineurin inhibitors (88.9%) and antimetabolites (73.2%). Antimetabolites (84.3%) and calcineurin inhibitors (54.3%) were discontinued/decreased 84.3% whereas glucocorticoids dosage almost has no change (77.9%) or even increased. 18.4% of cases had died, and 65.9% were discharged.

CONCLUSIONS

Patients' demographics, signs, symptoms, and radiographic findings in SOT recipients are almost similar to the general population. However, gastrointestinal symptoms appear to be more common. There are different treatment strategies, but in most of them, antimetabolite and calcineurin inhibitors were decreased or discontinued, while corticosteroids were increased. Finally, COVID-19 seems to be more severe and has higher mortality in SOT recipients compared to the general population.

Cathepsin-K is a potential cardiovascular risk biomarker in prevalent hemodialysis patients

PURPOSE

Cardiovascular (CV) disease remains the leading cause of mortality among end-stage kidney disease (ESKD) patients. Cathepsin-K (CatK), a small cysteine protease involved in bone and extracellular matrix remodeling, has recently emerged as a key-factor in the pathogenesis of various conditions predisposing to CV disease, including atherosclerosis, obesity, diabetes, and vascular calcification. In this pilot prospective study, we aimed at evaluating the clinical significance and the predictive power of CatK in a small cohort of hemodialysis (HD) patients.

METHODS

Cathepsin-K was measured in 54 prevalent HD patients and in 30 controls together with routine parameters. Patients were then followed up to 26 months and the time of cardiovascular death (endpoint of the study prospective phase) recorded.

RESULTS

CatK levels were increased in the HD cohort as compared with controls (p < 0.001). In HD patients, CatK was also independently correlated to PTH (β = 0.368; p = 0.001), alkaline phosphatase (β = 0.383; p < 0.001), C-reactive protein (β = 0.260; p = 0.01), and white cell count (β = - 0.219; p = 0.02). After baseline assessment, patients were followed for CV death (mean follow-up 24.8 ± 3.1 months). Kaplan-Meier analysis showed a worsen survival (log-rank p = 0.04) in HD patients with CatK levels > 440 pg/mL (best ROC-derived cut-off with 69.6% sensitivity and 79.8% specificity) with a crude HR (Mantel-Haenszel) of CV death of 3.46 (95% CI 1.89-13.44).

CONCLUSIONS

In prevalent HD patients, altered CatK levels may reflect mineral dysmetabolism and inflammation, and predict CV death in the mid-term. These preliminary findings prompt the rationale for further investigations on larger cohorts to validate CatK as a biomarker for improving CV risk stratification in ESKD.