Laurynas Rimševičius

Background: Central venous occlusive disease is a major challenge in hemodialysis patients who have exhausted conventional vascular access options and may lead to long-term dependence on tunneled central venous catheters. The Hemodialysis Reliable Outflow (HeRO) graft provides an alternative by bypassing obstructed central veins and enabling catheter-free upper-extremity vascular access. Case presentation: We report the first HeRO graft implantation in Lithuania in a 78-year-old woman with end-stage kidney disease and extensive central venous occlusive disease. Previous arteriovenous fistulas had failed because of thrombosis and severe venous hypertension, while prolonged catheter dependence was complicated by recurrent infections, dislodgements, and multiple catheter exchanges. The HeRO venous outflow component was implanted through the existing tunneled catheter access and positioned in the right atrium. It was connected to an early-cannulation expanded polytetrafluoroethylene graft anastomosed to the brachial artery. Completion fistulography demonstrated unobstructed flow through the system into the right atrium. The procedure was technically successful, and the graft was successfully cannulated for hemodialysis 24 h after implantation, avoiding the need for temporary catheter placement. Conclusions: The HeRO graft may provide a valuable catheter-sparing option for carefully selected hemodialysis patients with severe central venous occlusive disease and no feasible conventional upper-extremity access. This case demonstrates its technical feasibility in a complex vascular access setting and highlights the potential role of an early-cannulation graft when immediate catheter removal is necessary.

Background/Objectives: Posterior reversible encephalopathy syndrome (PRES) is a neurological condition characterized by acute neurological symptoms and vasogenic edema, usually affecting the posterior circulation. It is described in end-stage renal disease (ESRD), but its presentation in peritoneal dialysis (PD) is not well defined. We aimed to describe the clinical, radiological, and dialysis-related features of PRES in PD patients and highlight factors relevant for diagnosis and management. Materials and Methods: We conducted a retrospective descriptive case series of four ESRD patients on PD or recently transitioned from PD to hemodialysis (HD) who developed PRES at a single center. Clinical data, laboratory results, dialysis characteristics, and neuroimaging findings were obtained from medical records. PRES was diagnosed based on acute neurological symptoms in the setting of severe hypertension and uremia, with CT and/or MRI findings supportive of PRES when present and exclusion of alternative diagnoses. Results: All patients presented with acute neurological manifestations, including headache, visual disturbances, seizures, and/or altered consciousness, in the context of marked hypertension and uremia. Neuroimaging findings ranged from normal CT/MRI to subtle bilateral occipital hypodensities and, in one case, extensive supra- and infratentorial vasogenic edema with internal hydrocephalus and subependymal edema. In three patients, inadequate volume or solute control on PD prompted temporary or permanent transition to HD to improve blood pressure and fluid management. With antihypertensive therapy, seizure control when required, correction of metabolic disturbances, and optimization of dialysis, all patients recovered clinically, with time to PRES resolution ranging from 7 to 43 days. Conclusions: PRES should be considered in PD patients with new-onset seizures, visual symptoms, or unexplained changes in mental status, particularly during hypertensive crises and uremia. Early CT/MRI, prompt blood pressure control, and careful adjustment of dialysis modality appear important for achieving favorable neurological outcomes.

Background and Objectives: Extracellular matrix (ECM) and collagen remodeling contribute to chronic kidney disease (CKD) progression and vascular access dysfunction. Conventional histological techniques rely on staining and provide limited sensitivity for detecting early or subtle ECM alterations. Nonlinear optical imaging modalities, including second-harmonic generation (SHG), third-harmonic generation (THG), and multiphoton fluorescence (MPF) microscopy, enable label-free, high-resolution visualization of fibrillar collagen and may offer additional structural information. This study aimed to evaluate the added value of nonlinear imaging beyond conventional histology for assessing ECM remodeling in renal and vascular tissues. Materials and Methods: A systematic literature review was conducted in accordance with the PRISMA 2020 guidelines. PubMed and Web of Science were searched for studies published between 1 January 2015, and 4 April 2025, investigating ECM or collagen remodeling in renal or vascular tissues using SHG, THG, or MPF microscopy. After screening 115 records, 10 studies were included in the qualitative synthesis. In addition, representative SHG, THG, and MPF images of excised human arteriovenous fistula (AVF) tissue were acquired as illustrative feasibility examples to demonstrate the application of these imaging modalities. The use of human tissue was approved by the Vilnius Regional Biomedical Research Ethics Committee (approval No. 2022/6-1443-917). Results: The included studies demonstrated that nonlinear microscopy enables label-free assessment of collagen density, organization, and fiber orientation. SHG imaging differentiated healthy from diseased tissues and has been reported to support fibrosis assessment and staging in preclinical and selected clinical studies and revealed microstructural remodeling patterns not readily detected by conventional histology. The illustrative AVF images demonstrated collagen disorganization consistent with patterns reported in the reviewed literature and are presented solely to demonstrate imaging feasibility, without implying disease phenotype or clinical outcome associations. Conclusions: Nonlinear optical microscopy provides complementary structural information on ECM organization that is not accessible with standard histological techniques. Further validation and methodological standardization are required to support its broader application in clinical nephrology and vascular medicine.

Background/Objectives: Arteriovenous grafts (AVGs) are critical for hemodialysis access in patients with inadequate native vasculature. The Xeltis aXess graft, a novel bioresorbable vascular access conduit, promotes endogenous tissue restoration. While early outcomes have been promising, longer-term data remain limited. This report presents the longest reported, four-year follow-up on two of the first implanted aXess devices. Case Summaries: Case 1: A 64-year-old woman underwent aXess graft placement on 10 June 2021, between the right brachial artery and vein. She experienced graft thrombosis after 12 months and 18 months, both of which were successfully resolved with thrombectomy, in one instance in combination with drug-coated balloon (DCB) angioplasty. The graft remains functional. Case 2: A 76-year-old man received an aXess graft on 11 June 2021, in the left arm. After 6 months, he underwent balloon and DCB angioplasty for graft–vein (G–V) anastomosis stenosis. After 28 months, to resolve multiple pseudoaneurysms, followed by aneurysm resection and AVG reconstruction at month 29, a tunneled catheter was placed to perform dialysis sessions in the meantime. At month 44, graft-venous (G–V) angioplasty with DCB was performed to resolve G–V and axillary vein stenoses diagnosed at month 43. The graft remains in use. Results: Both patients retained functional dialysis access after four years, despite requiring multiple interventions for thrombosis, stenosis, and pseudoaneurysms. Conclusions: These cases demonstrate that the aXess graft can maintain functionality over four years with appropriate management, although close surveillance and reinterventions may be required.

Background/Objectives: Chronic kidney disease (CKD) requires intensive dietary and lifestyle management, yet patient engagement and access to tailored education remain limited, particularly outside clinical settings. This study describes the development and implementation of NephroGo, and evaluates its usability, user engagement, and perceived acceptability among patients with CKD. Methods: The app was developed based on clinical and dietary guidelines, incorporating personalized nutrient recommendations, dialysis tracking, and educational content. Technically, it features a Django backend, Flutter mobile frontend, and secure cloud-based hosting. User feedback was collected through one-time interviews (n = 10) and a standardized Mobile App Rating Scale (MARS) survey (n = 32). Longitudinal usage data over four years were also analyzed. Results: Initially, NephroGo was downloaded by 204 users, of whom 93.6% were considered active users based on defined behavioral engagement thresholds. Over a four-year period, the app accumulated a total of 1670 downloads. This study focuses on evaluating user engagement, usability, and perceived acceptability of the NephroGo app over a four-year period. Most users were female (52.3%) and aged 30–65. Stage 5 CKD patients and those undergoing peritoneal dialysis (PD) had the highest engagement. The most-used feature was the personalized nutrition calculator, with sodium being the most frequently exceeded nutrient. The average MARS score was 4.09 ± 0.66, with functionality rated highest (4.27 ± 0.74). App ratings were significantly higher among users referred by physicians (p = 0.039). Conclusions: NephroGo offers a scalable digital tool to support dietary management and health monitoring, with potential to complement standard nephrology care in a resource-conscious manner.

Background and Objectives: Kidney transplant recipients are at risk of developing more severe forms of COVID-19 infection. The aim of this study was to compare the clinical course of COVID-19 infection among kidney transplant patients and a control group. Materials and Methods: We examined 150 patients hospitalized with COVID-19 infection. Patients were divided into study (kidney transplant recipients, n = 53) and control (without a history of kidney transplantation, n = 97) groups. Demographics, clinical characteristics, treatment data, and clinical outcomes were assessed. Results: The median patient age was 56.0 (46.0–64.0) years, and seventy-seven patients (51.3%) were men. The median Charlson comorbidity index was higher in the study group (3.0 vs. 2.0, p < 0.001). There was a higher incidence of hypoxemia in the control group upon arrival (52.6% vs. 22.6%, p = 0.001) and a higher NEWS index median (2.0 vs. 1.0 points, p = 0.009) and incidence of pneumonia during hospitalization (88.7% vs. 73.6%, p = 0.023). In the study group, there were more cases of mild (26.4% vs. 11.3%, p = 0.023) and critically severe forms of COVID-19 infection (26.4% vs. 3.1%, p < 0.001), kidney failure was more prevalent (34.0% vs. 1.0%, p < 0.001), and a greater number of patients were transferred to the intensive care unit (22.6% vs. 3.1%, p < 0.001) and died (18.9% vs. 1.0%, p < 0.001). Multivariable analysis revealed that treatment in the intensive care unit correlated with a higher mortality rate than transplantation itself (HR = 20.71, 95% CI 2.01–213.33, p = 0.011). Conclusions: The course of the COVID-19 disease in kidney transplant recipients is heterogeneous and can be more severe than in the general population. Even though patients may be hospitalized with fewer symptoms, complications and death are more likely to occur.

Background and Objectives: Kidneys are one of the main targets for SARS-CoV-2. Early recognition and precautionary management are essential in COVID-19 patients due to the multiple origins of acute kidney injury and the complexity of chronic kidney disease management. The aims of this research were to investigate the association between COVID-19 infection and renal injury in a regional hospital. Materials and Methods: The data of 601 patients from the Vilnius regional university hospital between 1 January 2020 and 31 March 2021 were collected for this cross-sectional study. Demographic data (gender, age), clinical outcomes (discharge, transfer to another hospital, death), length of stay, diagnoses (chronic kidney disease, acute kidney injury), and laboratory test data (creatinine, urea, C-reactive protein, potassium concentrations) were collected and analyzed statistically. Results: Patients discharged from the hospital were younger (63.18 ± 16.02) than those from the emergency room (75.35 ± 12.41, p < 0.001), transferred to another hospital (72.89 ± 12.06, p = 0.002), or who died (70.87 ± 12.83, p < 0.001). Subsequently, patients who died had lower creatinine levels on the first day than those who survived (185.00 vs. 311.17 µmol/L, p < 0.001), and their hospital stay was longer (Spearman’s correlation coefficient = −0.304, p < 0.001). Patients with chronic kidney disease had higher first-day creatinine concentration than patients with acute kidney injury (365.72 ± 311.93 vs. 137.58 ± 93.75, p < 0.001). Patients with acute kidney injury and chronic kidney disease complicated by acute kidney injury died 7.81 and 3.66 times (p < 0.001) more often than patients with chronic kidney disease alone. The mortality rate among patients with acute kidney injury was 7.79 (p < 0.001) times higher than among patients without these diseases. Conclusions: COVID-19 patients who developed acute kidney injury and whose chronic kidney disease was complicated by acute kidney injury had a longer hospital stay and were more likely to die.

The population of patients with end‐stage renal disease is rapidly growing and hemodialysis remains the most common treatment option. We present a case of a young patient with arteriovenous fistula (AVF)‐related heart failure, and a review of the main hemodynamic changes after AVF formation and ligation procedures.

Background and Objectives: Kidney transplant recipients represent a unique population with metabolic abnormalities, altered nutritional and immune status, as well as an imbalanced regulation of adipocytokine metabolism. Leptin is a hormonally active protein mainly produced by fat tissue that modulates appetite, satiety, and influences growth, energy, and bone metabolism. There has been great interest in the role of this hormone in chronic kidney disease-related protein energy wasting; thus, a positive leptin correlation with body mass index and fat mass was confirmed. This study was designed to determine the association of pre and post-kidney transplant leptin concentration with nutritional status and body composition. Materials and Methods: We studied 65 kidney transplant recipients. Nutritional status was evaluated before kidney transplantation and 6 months later using three different malnutrition screening tools (Subjective Global Assessment Scale (SGA), Malnutrition Inflammation Score (MIS), and Geriatric Nutritional Risk Index (GNRI)), anthropometric measurements, and body composition (bioelectrical impedance analysis (BIA)). Demographic profile, serum leptin levels, and other biochemical nutritional markers were collected. Statistical analysis was performed with R software. Results: Median age of the studied patients was 45 years, 42% were females, and 12% had diabetes. Leptin change was associated with body weight (p < 0.001), waist circumference (p < 0.001), fat mass (p < 0.001) and body fat percentage (p < 0.001), decrease in parathyroid hormone (PTH) (p < 0.001) transferrin (p < 0.001), diabetes mellitus (p = 0.010), and residual renal function (p = 0.039), but not dependent on dialysis vintage, estimated glomerular filtration rate (eGFR), or delayed graft function at any time during the study. After adjustment for age and sex, body mass index (BMI) (p < 0.001), fat mass (p < 0.001), and body fat percentage (p < 0.001) were independent variables significantly associated with post-transplant leptin change. Lower leptin values were found both before and after kidney transplantation in the SGA B group. GNRI as a nutritional status tool was strongly positively related to changes in leptin within the 6-month follow-up period. Conclusions: Kidney transplant recipients experience change in leptin concentration mainly due to an increase in fat mass and loss of muscle mass. GNRI score as compared to SGA or MIS score identifies patients in whom leptin concentration is increasing alongside an accumulation of fat and decreasing muscle mass. Leptin concentration evaluation in combination with BIA, handgrip strength measurement, and GNRI assessment are tools of importance in defining nutrition status in the early post-kidney transplant period.