Introduction. Intradialytic hypotension (IDH) is a common complication of renal replacement therapy (RRT) sessions and may be a particularly detrimental factor in heart recipients. Objective: to investigate the incidence of IDH in heart recipients with acute kidney injury (AKI). Patients and Methods: Two groups of recipients were compared – the study group (SG), n = 313, in which 49 patients required intermittent RRT (IRRT) and in which online hemodiafiltration (OL-HDF) sessions were performed using acetate-free hydrochloric acid-based dialysate fluid; and control group (CG) n = 387, in which 88 patients required IRRT, where standard dialysate with an acetate ion content of 3 mmol/L was used for OL-HDF. Results. There was a significantly lower incidence of IDH in the SG compared to the CG: 10.46% vs 20.47% (p < 0.05). Conclusions. In heart recipients for whom IDH can be considered as a significant adverse factor, the use of acetate-free dialysis fluid can significantly reduce the incidence of this complication.

Kidney injury in cardiac transplant recipients is one of the most severe complications affecting both short- and long-term transplant outcomes. The need for renal replacement therapy (RRT) is determined not only and not so much by the degree of renal dysfunction, as by the need for correction of fluid balance and metabolic disorders. These circumstances are associated with the specificity of extracorporeal renal replacement therapy in donor heart recipients. In this review, we discuss the problems of early versus delayed initiation of RRT, anticoagulation and vascular access, advantages and disadvantages of continuous and intermittent techniques. Special attention is paid to chronic kidney injury and peculiarities of kidney transplantation in heart recipients.

Kidney injury in heart transplant recipients is of a complex nature and bears the features of all types of cardiorenal interaction impairment. Pre-transplant renal dysfunction, perioperative acute kidney injury, as well as factors associated with graft and immunosuppression, determine the prevalence and severity of kidney pathology in this group of patients. This review examines the pathophysiology of kidney dysfunction in heart failure, the epidemiology, and criteria for acute kidney injury.

Liver transplantation is the only effective treatment modality for end-stage liver disease. However, donor organs are not always available. In some cases, the gravity of the patient’s condition makes transplantation impossible. In this regard, the use of artificial liver support systems helps in preparing a patient for transplant surgery. Objective: to conduct a retrospective study aimed at evaluating the efficiency of fractionated plasma separation and adsorption system. Materials and methods. From January 2019 to May 2020, 139 pediatric liver transplants were. We analyzed the data of 5 pediatric patients (2 girls and 3 boys, aged 12 to 17 years) who received fractionated plasma separation and adsorption (FPSA) sessions as a bridge to transplantation. The main clinical indication for FPSA was severe hepatic encephalopathy (grade 3 according to the West Haven Criteria), which was observed at 350–872 μmol/L (average 597 ± 98 μmol/L) serum bilirubin level. The FPSA sessions were conducted on a Prometheus device using AV-600 hemofilters as dialyzers ( Fresenius Medical Care, Germany ). Results. Depending on the extent of bilirubinemia in patients, it took from one (in one case) to three (in one case) daily FPSA sessions to restore clear consciousness, appetite and physical activity. Average bilirubin levels after treatment cycles decreased from 597 ± 98 to 236 ± 73 μmol/L. All patients successfully underwent liver transplant surgery within two to five days, two patients received a liver fragment from a living related donor. Conclusion. The FPSA system stabilizes the condition of potential recipients with acute liver failure. Further research is required to develop optimal regimens for albumin dialysis.

Up-to-date technologies have led to significant improvement of haemodialysis membranes biocompatibility and permeability. The new classes of membranes, high cut-off and middle cut-off, allow enhanced removal of middle molecules such as β 2 -microglobulin and even larger molecules. High membrane permeability along with the wide use of convective modalities are accompanied by increased albumin loss during dialysis. What is the acceptable upper limit for this loss and where is the right balance between the benefit of enhanced uremic substances removal and potential adverse effects of albumin deprivation are the active areas of research.

Objective: to evaluate the dependence of the magnitude of convection flow in online hemodiafiltration (OLHDF) on ultrafiltration control method and patients’ individual characteristics. Materials and methods. The study included 36 stable dialysis patients (20 male and 16 female). The substitution rate was conducted manually based on transmembrane pressure (TMP). In some cases, devices with automatic filtration rate control unit AutoSub plus were used. The filtration rate (FR), TMP, blood flow rate (Qb), specific filtration rate (SFR, m/l/min/mm Hg–1 ) were recorded. Results. The maximum SFR in various patients ranged from 0.51 to 0.80 ml/min/mm Hg–1 ; average value was 0.62 ± 0.07 ml/min/mm Hg–1 . There was significant correlation of SFR with hemoglobin level (r = –0.55). SFR reduced during hemodiafiltration (on average – by 23 ± 4%). SFR was significantly affected by Qb (r = 0.70). Maximum SFR was achieved with a TMP of 140–220 mm Hg; with TMP over 250 mm Hg, a decrease in SFR was noted, an increase in Qb was required for further increase in FR. Individual stability of SFR was noted during serial observations; fluctuations in a particular patient did not exceed 10%. Substitution volume for the HDF session was 18.0 ± 3.3 L, the FR/Qb ratio was 24.7 ± 5.2%. Substitution volume of 21 L was not achieved in 17 of 36 patients. The use of automatic FR adjustment system made it possible to increase the substitution volume (SV) by 12–18%. Conclusion. Achieving maximum convection volume in OLHDF requires individualizing treatment parameters. The use of FR automatic control allows maximum possible convection flow.

Apart from its main electrolytes – sodium, potassium, calcium and magnesium – a dialysis fluid (DF) contains a buffer for correction of acidosis. A small amount of acid is added to the DF to prevent calcium and magnesium precipitation. Acetic acid has traditionally been used for this purpose. Several studies have shown that acetate ion, even in small concentrations, can cause a number of adverse events, such as low blood pressure, production of proinflammatory cytokines, etc. This literature review aims at considering alternative acidic components of DF, such as citric, hydrochloric, and succinic acids, as well as their advantages, possibilities and features of their use in wide clinical practice.

Currently, kidney transplantation and hemodialysis are the primary therapies for end-stage renal disease. High mortality, mostly caused by cardiovascular disease, remains the main challenge in the treatment of this category of patients. It has been shown that in patients with end-stage chronic kidney disease undergoing hemodialysis, the risk of mortality due to cardiovascular disease is up to 20 times higher than in the sex- and age-matched general population. The indicated data determined the appropriateness of isolating cardiorenal relationships into a single cardiorenal syndrome (CRS). Due to the facts mentioned above, intravascular imaging methods, notably optical coherence tomography (OCT), are particularly important in diagnosing coronary artery lesions. This review analyses the data published to date on the features and capabilities of OCT in CRS patients.

The conceptual design for portable equipment for low-flow detoxification of the body by peritoneal dialysis is proposed. It uses dialysis−sorption or dialysis−electrochemical (with sorption aftertreatment) technologies of regeneration of the spent solution for peritoneal dialysis.

Aim. To examine the assumption that significant concentrations of cystatin C in urine are the manifestation of the tubular necrosis and, respectively, the severity of kidney damage after heart transplantation (HTx).Materials and methods. In this study we evaluated 33 heart recipients (6 women and 27 men, aged from 24 to 68 years old) who had risk factors of acute kidney injury: serum creatinine level >113 μmol/l and/or mechanical circulatory support requirement (20 patients, in 14 cases before HTx). Cystatin C concentration in serum and in urine was measured by DyaSis particle-enhanced immunoturbidimetric assay test «Cystatin C FS».Results. Recipients were divided into two groups according to the levels of cystatinuria. In the group with the significant (more than 0.18 mg/l) urinary cystatin C concentrations the requirement of renal replacement therapy (RRT) was 2.5-fold higher, and the mean duration of RRT was more than 10-fold longer. In 2 patients with the significant cystatinuria acute kidney injury (AKI) has transformed into end-stage renal disease (ESRD).Conclusion. Due to data obtained we may suppose that significant concentrations of cystatin C in urine are the marker of the tubular necrosis with the prolonged RRT requirement. Further studies are needed to justify this relationship.

Aim . To examine the assumption that significant concentrations of cystatin C in urine are the manifestation of the tubular necrosis and, respectively, the severity of kidney damage after heart transplantation (HTx). Materials and methods . In this study we evaluated 33 heart recipients (6 women and 27 men, aged from 24 to 68 years old) who had risk factors of acute kidney injury: serum creatinine level >113 μmol/l and/or mechanical circulatory support requirement (20 patients, in 14 cases before HTx). Cystatin C concentration in serum and in urine was measured by DyaSis particle-enhanced immunoturbidimetric assay test «Cystatin C FS». Results . Recipients were divided into two groups according to the levels of cystatinuria. In the group with the significant (more than 0.18 mg/l) urinary cystatin C concentrations the requirement of renal replacement therapy (RRT) was 2.5-fold higher, and the mean duration of RRT was more than 10-fold longer. In 2 patients with the significant cystatinuria acute kidney injury (AKI) has transformed into end-stage renal disease (ESRD). Conclusion. Due to data obtained we may suppose that significant concentrations of cystatin C in urine are the marker of the tubular necrosis with the prolonged RRT requirement. Further studies are needed to justify this relationship.

The development of kidney injury and the characteristics of renal replacement therapy were considered in patient with dilated cardiomyopathy, who consequently underwent two heart transplantations and two kidney transplantations. Since the number of the patients needed both kidney and heart transplantation increases constantly, the multifaceted thorough research in this specific patient population is extremely important.

Hyperhydration, the sum of persistent (PH) and intermittent (IH) ones is the strong predictor of mortality in patients on program haemodialysis (PHD). The aim of this research was to investigate the complex of methods for minimization of PH as well as IH. Materials and methods. The bioimpedance multifrequency analysis (BIA), relative blood volume (RBV) monitoring and plasma conductivity evaluation by ionic dialysance device were performed in candidates for kidney transplantation. Results. In 380 PHD patients, comparing with 26 healthy persons the expansion of extracellular volume was only observed even in the cases of the huge (3.5–15 L) overload. PH of more than 15% of extracellular volume was observed in 41% of patients. The deviation of hydration status from reference value was 3.7 ± 1.4 L at first measurement and 1.9 ± 1.2 L at last one in every patient. RBV decreased insignificantly (less than 2.5% / L ultrafiltration) during PHD sessions in patients with PH. This value increased after dry weight consummation and it appeared as surrogate of intravascular refueling capacity. The minimization of sodium dialysate – plasma gradient resulted in decrease of IH. Conclusion. The elimination of both PH and IH in PHD patients is the paramount goal; it demands the complex approaches and further investigations.

At present, online hemodia fi ltration is the most effective dialysis modality as it uses a combination of diffusive and convective transmembrane solute transport. First part of this review summarizes historical, technical aspects and international standards for online hemodia fi ltration.

Intravascular volume preservation is the fi rst choice measure for the prevention of intradialysis hypotension. At present there are devices that allow continuous monitoring of relative blood volume (RBV) changes during haemodialysis (HD). The aim of this research was to investigate (i) the regularity of RBV curve during haemo- dialysis and (ii) the ef fi cacy of some measures for intravascular volume preservation. In patients with hyperhydration RBV curves were monotone; in all cases relation  RBV/ ultra fi ltration volume (UF) did not exceed 2,5%/L. In stable patients the RBV curve was immutable in the course of years. Patients with high  RBV/UF ratio (>6%/L) formed a high risk group. In these patients stability of RBV was more im- portant and more useful. Isolated UF did not decrease RBV drop, as well as haemodia fi ltration online. Albumin administration allows to decrease  RBV/UF ratio. After bolus of hypertonic dextrose solution RBV increased for about half of hour. In patients with acute renal injury RBV monitoring was far from reliability in many cases.

Second part of review summarizes legal and financial aspects of online hemodiafiltration and its influence on short-term and long-term treatment results. According to recently completed randomized clinical trials, high vo- lume online hemodiafiltration is able to improve patients' survival rate. The results mentioned in the review must overpower the inertia which obstructs a wide implementation of online hemodiafiltration into routine clinical practice.

The experience of the introduction of convective methods since the eighties of the 20th century is described. Aim: to evaluate the influence of convective transport supplementation on renal replacement therapy results. Methods and results. The number of convective procedures was applied: hemodiafiltration with commercial substituted fluid, paired filtration dialysis, acetate-free biofiltration, original hybrid methods, online hemodiafiltration. The main trend was the magnification of substituted volume. In the long run after switching from conventional dialysis to convective therapy the increase of Kt/V, the decline of phosphate, the rise of serum albumin, the decrease of CRP level and ESA consumption, QOL improvement and the drop in severity of intradialysis complications were observed. Over last six years online hemodiafiltration has become the standard of dialysis therapy in our Center. Conclusion. The undoubted advantages of convective modalities and accessibility of online hemodiafi ltration make these methods the gold standard of dialysis therapy.

The experience of the introduction of convective methods since the eighties of the 20th century is described. Aim:  to evaluate the infl uence of convective transport supplementation on renal replacement therapy results. Methods  and results. The number of convective procedures was applied: hemodiafi ltration with commercial substituted fl uid, paired fi ltration dialysis, acetate-free biofi ltration, original hybrid methods, online hemodiafi ltration. The main trend was the magnifi cation of substituted volume. In the long run after switching from conventional dialysis to convective therapy the increase of Kt/V, the decline of phosphate, the rise of serum albumin, the decrease of CRP level and ESA consumption, QOL improvement and the drop in severity of intradialysis complications were observed. Over last six years online hemodiafi ltration has become the standard of dialysis therapy in our Center. Conclusion. The undoubted advantages of convective modalities and accessibility of online hemodiafi ltration make these methods the gold standard of dialysis therapy.