Peritoneal videodialysis: first Italian audit

Conceived and developed since 2001 at the Alba Center, Videodialysis (VD) was used initially to prevent dropout in prevalent PD patients by guiding them in performing dialysis (VD-Caregiver). Subsequently, its use was extended to the clinical follow-up of critical patients (VD-Clinical), problems relating to transport to the Center (VD-Transport), and since 2016 for training/retraining all patients (VD-Training). Since 2017 other Centers have employed VD using modalities analyzed in this paper. Methods: the paper reports the findings of an Audit (February 2021) of the Centers using VD on 31-12-2020. The Centers provided the following information: the characteristics of the patients using VD; the main and secondary reasons for using VD, considering nursing home (VD-NH) patients separately; VD outcomes: duration, drop-out, peritonitis, patient/caregiver satisfaction (minimum: 1 - maximum: 10). Results: VD, which began between 09-2017 and 12-2019, has been used in 6 Centers for 54 patients at 31-12-2020 (age:71.8±12.6 years - M:53.7% - CAPD:61.1% - Assisted PD:70.3%). The most frequent reason has been VD-Training (70.4%), followed by VD-Caregiver (16.7%), VD-NH (7.4%), VD-Clinical (3.7%), and VD-Transport (1.9%), with differences between Centers. VD-Training is used most with self-care patients (93.8% - p<0.05), while with patients on Assisted PD it is associated with secondary reasons (95.7% - p<0.02). VD-Training (duration: 1-4 weeks) has always been completed successfully. No peritonitis was reported; satisfaction was 8.4±1.4. Conclusion: videodialysis is a flexible, effective, safe, and valued tool that can be employed using various modalities depending on the choice of the Center and the complexity of the patient.

[Vascular ultrasonography in the preparation and surveillance of arteriovenous fistula: a monocentric experience]

Creating an arteriovenous fistula (AVF) is complicated by the gradual increase in the average age of patients initiating chronic haemodialysis treatment and by the greater prevalence of pathologies that impact the cardiovascular system. In the past, the choice of which vessels to use for the creation of the AVF was essentially based on the physical examination of the upper limbs. Current international guidelines suggest that a colour doppler ultrasound (DUS) should be performed to complete the physical examination. Similarly, vascular ultrasound is fundamental in the post-operative phase for appropriately monitoring the access. We have conducted a retrospective analysis on the use of DUS in clinical practice in our centre, in order to determine the repercussions on vascular access survival. To this end, we identified three phases, according to the methods that were used for pre-operative vascular evaluation and monitoring of the AVF, that saw the progressive integration of clinical and ultrasound parameters. The analysis of the data highlighted a statistically significant higher rate of survival for all vascular accesses, evaluated as a whole, and for distal AVFs, in the third phase, despite a greater percentage of patients over 75 (48% vs 28%). In conclusion, we believe that an approach integrating clinical and ultrasound evaluation is indispensable to identify the most suitable AVF site and guarantee its efficiency over time.

Increase of continuous treatments and regional citrate anticoagulation during renal replacement therapy in the ICUs of the north-west of Italy from 2007 to 2015

BACKGROUND

Few reports have addressed the change in Renal Replacement Therapy (RRT) management in the ICUs over the years in western countries. This study aims to assess the trend of dialytic practice in a 4.5-million population-based study of the northwest of Italy.

METHODS

A nine-year survey covering all the RRT provided in the ICUs. Consultant nephrologists of the 26 Nephrology and Dialysis centers reported their activities in the years 2007, 2009, 2012, and 2015.

RESULTS

From 2007 to 2015 the patients treated increased from 1042 to 1139, and the incidence of RRT from 254 to 263 cases/10^6 inhabitants. The workload for Dialysis Center was higher in the larger hub hospitals. RRT for Acute Kidney Injury (AKI), continuation of treatment in chronically dialyzed patients, or extrarenal indications accounted for about the stable rate of 70, 25 and 5% of all RRT sessions, respectively. Continuous modality days increased from 2731 days (39.5%) in 2007 to 5076 (70.6%) in 2015, when the continuous+prolonged treatment days were 6880/7196 (95.6% of total days). As to RRT timing, in 2015 only the classical clinical criteria, and no K-DIGO stage were adopted by most Centers. As to RRT interruption, in 2015 urine volume was the first criterion. Implementation of citrate anticoagulation (RCA) for RRT patients significantly increased from 2.8% in 2007 to 30.9% in 2015, when it was applied in all 26 Centers.

CONCLUSIONS

From 2007 to 2015, current practice has changed towards shared protocols, with increasing continuous modality and RCA implementation.

Citrate high volume on-line hemodiafiltration modulates serum Interleukin-6 and Klotho levels: the multicenter randomized controlled study "Hephaestus"

BACKGROUND

Studies addressing the anti-inflammatory properties of citrate dialysate enrolled patients in both hemodialysis (HD) and hemodiafiltration (HDF), the latter not adjusted for adequate convective exchange. This is a potential source of confounding in that HDF itself has anti-inflammatory effects regardless of the buffer, and optimal clinical outcomes are related to the amount of convection.

METHODS

To distinguish the merits of the buffer from those of convection, we performed a 6-month, prospective, randomized, crossover AB-BA study. Comparisons were made during the 3-month study period of on-line HDF with standard dialysate containing three mmol of acetic acid (OL-HDFst) and the 3-month of OL-HDF with dialysate containing one mmol of citric acid (OL-HDFcit). Primary outcome measure of the study was interleukin-6 (IL-6). Klotho, high sensitivity C-reactive protein (hsCRP), fetuin and routine biochemical parameters were also analyzed.

RESULTS

We analyzed 47 patients (mean age 64 years, range 27-84 years) enrolled in 10 participating Nephrology Units. Convective volumes were around 25 L/session with 90 percent of sessions > 20 L and ß2-microglobulin reduction rate 76% in both HDFs. Baseline median IL-6 values in OL-HDFst were 5.6 pg/ml (25:75 interquartile range IQR 2.9:10.6) and in OL-HDFcit 6.6 pg/ml (IQR 3.4:11.4 pg/ml). The difference was not statistically significant (p 0.88). IL-6 values were lower during OL-HDFcit than during OL-HDFst, both when analyzed as the median difference of overall IL-6 values (p 0.02) and as the median of pairwise differences between the baseline and the 3-month time points (p 0.03). The overall hsCRP values too, were lower during OL-HDFcit than during OL-HDFst (p 0.01). Klotho levels showed a time effect (p 0.02) and the increase was significant only during OL-HDFcit (p 0.01).

CONCLUSIONS

Citrate buffer modulated IL-6, hsCRP and Klotho levels during high volume OL-HDF. These results are not attributable to differences in the dialysis technology that was applied and may suggest a potential biological effect of citrate on CKD-associated inflammatory state. ClinicalTrials.gov identifier NCT02863016.

Clinical exome sequencing is a powerful tool in the diagnostic flow of monogenic kidney diseases: an Italian experience

Background

A considerable minority of patients on waiting lists for kidney transplantation either have no diagnosis (and fall into the subset of undiagnosed cases) because kidney biopsy was not performed or histological findings were non-specific, or do not fall into any well-defined clinical category. Some of these patients might be affected by a previously unrecognised monogenic disease.

Methods

Through a multidisciplinary cooperative effort, we built an analytical pipeline to identify patients with chronic kidney disease (CKD) with a clinical suspicion of a monogenic condition or without a well-defined diagnosis. Following the stringent phenotypical and clinical characterization required by the flowchart, candidates meeting these criteria were further investigated by clinical exome sequencing followed by in silico analysis of 225 kidney-disease-related genes.

Results

By using an ad hoc web-based platform, we enrolled 160 patients from 13 different Nephrology and Genetics Units located across the Piedmont region over 15 months. A preliminary “remote” evaluation based on well-defined inclusion criteria allowed us to define eligibility for NGS analysis. Among the 138 recruited patients, 52 (37.7%) were children and 86 (62.3%) were adults. Up to 48% of them had a positive family history for kidney disease. Overall, applying this workflow led to the identification of genetic variants potentially explaining the phenotype in 78 (56.5%) cases.

Conclusions

These results underline the importance of clinical exome sequencing as a versatile and highly useful, non-invasive tool for genetic diagnosis of kidney diseases. Identifying patients who can benefit from targeted therapies, and improving the management of organ transplantation are further expected applications.

Electronic supplementary material

The online version of this article (10.1007/s40620-020-00898-8) contains supplementary material, which is available to authorized users.

P0051NOVEL AND KNOWN MUTATIONS IDENTIFIED BY CLINICAL EXOME SEQUENCING FOR THE DIAGNOSIS OF POLYCYSTIC KIDNEY DISEASE

Background and Aims

Autosomal dominant PKD determines formation of multiple cysts predominantly in the kidneys and usually becomes symptomatic during adulthood and can lead to renal failure. In contrast, in autosomal recessive PKD cysts occur in both the kidneys and the liver and usually presents an earlier onset. Obtaining genetic diagnosis is important to confirm clinical diagnosis and is required before treating with vasopressin 2 receptor blockers, which are the only drugs known to slow down the disease. Furthermore, in the case of kidney transplant from a living family member it is essential to exclude the presence of the mutation in the donor. We used clinical exome sequencing to provide genetic diagnosis to a cohort of patients with a clinical suspicion of PKD.

Method

175 patients were referred to the Immunogenetics and Transplant Biology Service of the Turin University Hospital through a network of nephrology centers operating in the Piedmont region. Some patients were referred following genetic counseling. All patients signed an informed consent and the referring physicians provided relevant clinical data. DNA from eligible patients was extracted, checked for integrity, quantified and used for library preparation. A clinical exome sequencing (CES) kit by Illumina was used, allowing the analysis of 6,700 clinically relevant genes.

Results

Out of the 175 recruited patients eligible for CES, 38 (21.7%) had a clinical suspicion or diagnosis of PKD, with 50% of them presenting family history. The majority of the cohort was represented by male subjects (60.5%) and included both children (34.2%) and adults. The analytical approach was based on initial analysis of genes responsible for PKD (PKD1, PKD2 and PKHD1). If no mutation could be identified, analysis was then extended to a panel of 99 genes responsible for ciliopathies. This approach led to the identification of causative variants in 33/38 (86.8%) of the PKD cohort, while no variant could be identified in 5/38 patients. In 5/33 (15.2%) patients, mutations were inconclusive as found in heterozygosity in genes known to have an autosomal recessive mode of inheritance, while 27/33 (81.8%) were in line with the initial clinical suspicion/diagnosis. Of these, the majority was represented by missense mutations (12), followed by frameshift and nonsense mutations (6 each) and 3 splicing variants. As expected, the majority of mutations were found in PKD1 17/27 (63%), PKD2 3/27 (11.1%) and PKHD1 2/27 (7.4%). In these two latter patients, variants were found as compound heterozygosity. We also found mutations in other genes known to cause cysts, including TSC2 and CPT2. Of note, in 7 patients carrying PKD1 mutations, we found a second variant in PKD1 or PKHD1. Interestingly, when looking at patients characterized by kidney failure but lacking a clinical suspicion at recruitment or diagnosed with other phenotypes (66/175), we found variants in PKD1 and in PKD2 in 11 patients (9 and 2, respectively).

Of all identified variants in PKD1, PKD2 and PKHD1 genes, 17.6% were annotated as pathogenic (C5), 41.2% were likely pathogenic (C4) and 41.2% were variants of unknown significance (C3). 19 variants in these genes were not previously reported. All the variants found in genes responsible for PKD were validated and confirmed by Sanger sequencing. Family segregation studies are ongoing.

Finally, it is worth mentioning that in a portion of cases (5/38) with clinical and phenotypic features of PKD, supported also by a positive family history, we could not detect mutations in causative genes. These results may be explained by the presence of intronic variants, in line with data reported in literature.

Conclusion

These results demonstrate that CES may be applied to PKD patients to identify causative variants during their routine diagnostic flow. Furthermore, CES may be a useful tool to detect mutations in PKD-related genes in patients with undiagnosed diseases, considering its rapidly decreasing costs.

Effectiveness of Switch to Erythropoiesis-Stimulating Agent (ESA) Biosimilars versus Maintenance of ESA Originators in the Real-Life Setting: Matched-Control Study in Hemodialysis Patients

BACKGROUND

In hemodialysis (HD), switching from erythropoiesis-stimulating agent (ESA) originators to biosimilars is associated with the need for doses approximately 10% higher, according to industry-driven studies.

OBJECTIVE

The aim of this study was to evaluate the efficacy on anemia control of switching from ESA originators to biosimilars in daily clinical practice.

METHODS

We retrospectively selected consecutive HD patients receiving stable intravenous ESA doses, and who had not been transfused in the previous 6 months, from 12 non-profit Italian centers. Patients switched from originators to biosimilars (n = 163) were matched with those maintained on ESA originators (n = 163) using a propensity score approach. The study duration was 24 weeks, and the primary endpoint was the mean dose difference (MDD), defined as the difference between the switch and control groups of ESA dose changes during the study (time-weighted average ESA dose minus baseline ESA dose).

RESULTS

Age (70 ± 13 years), male sex (63%), diabetes (29%), history of cardiovascular disease (40%), body weight (68 ± 14 kg), vascular access (86% arteriovenous fistula), hemoglobin [Hb] (11.2 ± 0.9 g/dL) and ESA dose (8504 ± 6370 IU/week) were similar in the two groups. Hb remained unchanged during the study in both groups. Conversely, ESA dose remained unchanged in the control group and progressively increased in the switch group from week 8 to 24. The time-weighted average of the ESA dose was higher in the switch group than in the control group (10,503 ± 7389 vs. 7981 ± 5858 IU/week; p = 0.001), leading to a significant MDD of 2423 IU/week (95% confidence interval [CI] 1615-3321), corresponding to a 39.6% (95% CI 24.7-54.6) higher dose of biosimilars compared with originators. The time-weighted average of Hb was 0.2 g/dL lower in the switch group, with a more frequent ESA hyporesponsiveness (14.7 vs. 2.5%). Iron parameters and other resistance factors remained unchanged.

CONCLUSIONS

In stable dialysis patients, switching from ESA originators to biosimilars requires 40% higher doses to maintain anemia control.

Peritoneal ultrafiltration in refractory heart failure: a cohort study

INTRODUCTION

Acutely decompensated heart failure (HF) in patients with diuretic resistance is often treated with extracorporeal ultrafiltration. Peritoneal ultrafiltration (PUF) has been proposed for the long-term management of severe HF after resolution of the acute episode. The aim of the present study was to evaluate the use of PUF in the treatment of chronic refractory HF in patients without end-stage renal disease. ♢

METHODS

This multicenter (10 nephrology departments throughout Italy) retrospective observational study included patients with severe HF refractory to maximized drug treatment. The patients were proposed for PUF because they had experienced at least 3 hospital admissions in the preceding year for acutely decompensated HF requiring extracorporeal ultrafiltration. ♢

RESULTS

Of the 48 study patients (39 men, 9 women; mean age 74 ± 9 years), 30 received 1 nocturnal icodextrin exchange, 5 required 2 daily exchanges, and 13 received 2 - 4 sessions per week of automated peritoneal dialysis. During the first year, renal function remained stable (initial: 20.8 ± 10.0 mL/min/1.73 m(2); end: 22.0 ± 13.6 mL/min/1.73 m(2)), while pulmonary artery systolic pressure declined to 40 ± 6.09 mmHg from 45.5 ± 9.18 mmHg (p = 0.03), with a significant concomitant improvement in New York Heart Association functional status. Hospitalizations decreased to 11 ± 17 days/patient-year from 43 ± 33 days/patient-year before the start of PUF (p < 0.001). The incidence of peritonitis was 1 episode in 45 patient-months. Patient survival was 85% at 1 year and 56% at 2 years. ♢

CONCLUSIONS

This study confirms the satisfactory results of using PUF for chronic HF in elderly patients.

[Midarm arteriovenous fistula: single-center experience]

In uremic patients on hemodialysis, a first vascular access using native vessels tailored into a radiocephalic arteriovenous fistula (AVF) on the wrist is the gold standard in vascular access quality. However, among the uremic population the percentage of older patients affected by diabetes or by severe generalized vascular disease is growing. In these patients distal radiocephalic AVFs often have a limited survival. This induced us to design a technique for tailoring vascular accesses at a proximal site. In the past two years (2006-2007) we created 19 AVFs at the midarm position (midarm AVF) using the proximal section of the radial artery. Midarm AVF was the second choice in 70% of patients after failure of a distal AVF and the first choice in 30% of patients. The survival of this type of access has been excellent. We have registered only one thrombosis after 6 months. In four cases access was interrupted because of the death of the patients. The remaining 14 accesses are working perfectly well. Our experience leads us to conclude that midarm AVF is not only an important intermediate step after the failure of a distal AVF and before the application of a proximal AVF, but in a population of patients with diabetes and generalized vascular disease it should probably be proposed as the AVF of choice.

[Experience in the surveillance of arteriovenous fistula in Verbania, Italy]

One hundred forty-five patients are receiving renal replacement therapy at our center: 127 are on hemodialysis, 18 on peritoneal dialysis. From 2000 through 2005 a total of 215 arteriovenous fistulas (57% distal, 31% proximal, 12% prosthesis) were created. After some time we felt the necessity to design a vascular access surveillance system because the uremic population was increasingly constituted by aged people, including many diabetics and people suffering from hypertension with generalized vascular disease. The system comprised objective examination of the access at every dialysis session; kinetic Kt/V every 3 months; and a recirculation test (GIT) every 6 months. When there were anomalies in one of the above test results, color Doppler was performed. Detection of major stenosis with altered velocity parameters was a clear indication for angiography, possibly followed by angioplasty (PTA). In the indicated period, 15 patients underwent this procedure, and PTA was performed in all of them, often with placement of an endovascular stent. The results showed a survival of 12 months in 85% of patients and 18 months in 71% of patients. On the whole these data are comparable with others in the medical literature. The incidence of restenosis can be considered acceptable: it occurred in 3 cases out of 15 and could be corrected by PTA. In conclusion, PTA plus stent implantation is a valid method allowing quick and reliable correction of stenosis; a vascular access surveillance protocol and color Doppler imaging allow patient selection for angiography. PTA is to be considered an intermediate phase in stenosis correction before suggesting a new vascular access intervention to the patient.

Verapamil versus amlodipine in proteinuric non-diabetic nephropathies treated with trandolapril (VVANNTT study): design of a prospective randomized multicenter trial

Angiotensin converting enzyme inhibitors (ACEI) are the most effective antiproteinuric agents and should be used as first-line drugs in both diabetic and non-diabetic proteinuric nephropathies. The role of calcium channel blockers (CCB) is much more controversial. In diabetic patients verapamil and diltiazem seem more effective than dihydropyridines in reducing urinary protein excretion, and have additive effects with ACEI, but little is available on chronic treatment of non-diabetic nephropathies for non-dihydropyridine CCBs. To test whether the combination of verapamil 180 mg or amlodipine 5 mg with trandolapril 2 mg reduces urinary protein excretion more than trandolapril 2 mg alone, we planned a prospective, randomized, double-blind, multicenter trial. The secondary aims are to evaluate the effects of both treatments on the selectivity of proteinuria and check their safety. Consecutive patients aged between 18 and 70 years with non-diabetic proteinuria > or =2 g/24 h and plasma creatinine < 3 mg/dl or creatinine clearance > or = 20 ml/min are asked to participate. After a four-week run-in during which previous antihypertensive therapy is withdrawn, a single dose of trandolapril 2 mg is given once a day in open conditions for four weeks. At the end of this period patients are randomly assigned to receive once a day, in a double blind fashion, either trandolapril 2 mg and verapamil 180 mg [plus a placebo], or trandolapril 2 mg plus amlodipine 5 mg. They are monitored after one, two, five and eight months.