The renal replacement therapy landscape in 2030: reducing the global cardiovascular burden in dialysis patients

Relación entre bienestar psicológico y la percepción de calidad de vida en pacientes en hemodiálisis

Introducción: La hemodiálisis es la alternativa terapéutica más empleada en los pacientes con enfermedad renal crónica; sin embargo, no se han establecido de forma multidimensional las condiciones de bienestar psicológico y la calidad de vida de estos pacientes.Objetivo: Analizar el perfil de bienestar psicológico y percepción de calidad de vida de pacientes en hemodiálisis, así como diferenciar e identificar la relación entre estas variables.Material y método: Estudio observacional descriptivo transversal realizado a 173 pacientes en hemodiálisis. Se emplearon los cuestionarios PGWBI para evaluar el bienestar psicológico y el WHOQOL-BREF para la calidad de vida.Resultados: Pacientes con ERC en tratamiento con HD con un promedio de 57,59±13,31 años, predominantemente de género masculino (n=110; 63,58%). Se encontraron altos índices de bienestar psicológico (78,61%) y percepciones moderadas de calidad de vida (54,91%), acompañadas de sintomatología depresiva (97,11%) y ansiosa (97,11%). La edad, nivel educativo, condición laboral, ingresos económicos, tener Diabetes Mellitus y concentraciones sanguíneas inadecuadas de hemoglobina, potasio y fósforo, mostraron diferencias en los dominios y categorías (p<0,01). El análisis correlacional encontró una estrecha relación lineal entre las dos variables estudiadas (r=0,81; p=0,0001).Conclusiones: Los participantes del estudio mostraron altas percepciones de bienestar psicológico y moderadas apreciaciones de calidad de vida a expensas de elevadas valoraciones de positividad, autocontrol, vitalidad y percepciones de salud física, psicológica y relaciones sociales. El bienestar psicológico desde sus diferentes categorías influencia directamente la percepción de calidad de vida de los pacientes en hemodiálisis.

Ultrasonographic assessment of entheseal sites of upper and lower extremities in hemodialysis patients using Madrid Sonography Enthesitis Index

Background

There is no much information about the entheseal involvement among hemodialysis (HD) patients. The aim of this study was to assess the frequency and distribution of ultrasonographic (US) entheseal alterations in HD patients and to evaluate the association between US abnormalities and both clinical and laboratory data.

Methods

This study was conducted on 41 HD patients and 23 sex- and age- matched controls. All participants were evaluated clinically for any signs of enthesopathy. Six entheses sites were scanned bilaterally using grey scale (GS) and power Doppler (PD) US and were scored using Madrid Sonography Enthesitis Index (MASEI) scoring system.

Results

In HD patients, at least one clinical sign suggestive of enthesopathy was found in 69 (14%) of 492 entheses. HD patients had statistically significant higher scores of structural tendon abnormalities (p < 0.001), enthesis thickening (p < 0.001), bone erosions (p < 0.001) and calcification (p = 0.037) than the healthy controls. Total MASEI score was higher in HD patients than healthy controls (median;18 vs 8, p < 0.001), also, MASEI-inflammatory (median;11 vs 3, p < 0.001) and damage scores (median;6 vs 0, p < 0.001). There was a statistically significant positive association between total MASEI score and both age (p = 0.032) and duration of HD (p = 0.037). Duration of HD was predictive for both MASEI-damage component (p = 0.004) and total MASEI score (p = 0.014).

Conclusion

There is a high prevalence of subclinical enthesopathy in HD patients. The entheseal US alterations is much higher in HD patients than in healthy subjects. The duration of HD is the significant predictor of enthesopathy in HD patients.

Hidden risks associated with conventional short intermittent hemodialysis: A call for action to mitigate cardiovascular risk and morbidity

The development of maintenance hemodialysis (HD) for end stage kidney disease patients is a success story that continues to save many lives. Nevertheless, intermittent renal replacement therapy is also a source of recurrent stress for patients. Conventional thrice weekly short HD is an imperfect treatment that only partially corrects uremic abnormalities, increases cardiovascular risk, and exacerbates disease burden. Altering cycles of fluid loading associated with cardiac stretching (interdialytic phase) and then fluid unloading (intradialytic phase) likely contribute to cardiac and vascular damage. This unphysiologic treatment profile combined with cyclic disturbances including osmotic and electrolytic shifts may contribute to morbidity in dialysis patients and augment the health burden of treatment. As such, HD patients are exposed to multiple stressors including cardiocirculatory, inflammatory, biologic, hypoxemic, and nutritional. This cascade of events can be termed the dialysis stress storm and sickness syndrome. Mitigating cardiovascular risk and morbidity associated with conventional intermittent HD appears to be a priority for improving patient experience and reducing disease burden. In this in-depth review, we summarize the hidden effects of intermittent HD therapy, and call for action to improve delivered HD and develop treatment schedules that are better tolerated and associated with fewer adverse effects.

Blood-incompatibility in haemodialysis: alleviating inflammation and effects of coagulation

Blood-incompatibility is an inevitability of all blood-contacting device applications and therapies, including haemodialysis (HD). Blood leaving the environment of blood vessels and the protection of the endothelium is confronted with several stimuli of the extracorporeal circuit (ECC), triggering the activation of blood cells and various biochemical pathways of plasma. Prevention of blood coagulation, a major obstacle that needed to be overcome to make HD possible, remains an issue to contend with. While anticoagulation (mainly with heparin) successfully prevents clotting within the ECC to allow removal of uraemic toxins across the dialysis membrane wall, it is far from ideal, triggering heparin-induced thrombocytopenia in some instances. Soluble fibrin can form even in the presence of heparin and depending on the constitution of the patient and activation of platelets, could result in physical clots within the ECC (e.g. bubble trap chamber) and, together with other plasma and coagulation proteins, result in increased adsorption of proteins on the membrane surface. The buildup of this secondary membrane layer impairs the transport properties of the membrane to reduce the clearance of uraemic toxins. Activation of complement system-dependent immune response pathways leads to leukopenia, formation of platelet–neutrophil complexes and expression of tissue factor contributing to thrombotic processes and a procoagulant state, respectively. Complement activation also promotes recruitment and activation of leukocytes resulting in oxidative burst and release of pro-inflammatory cytokines and chemokines, thereby worsening the elevated underlying inflammation and oxidative stress condition of chronic kidney disease patients. Restricting all forms of blood-incompatibility, including potential contamination of dialysis fluid with endotoxins leading to inflammation, during HD therapies is thus still a major target towards more blood-compatible and safer dialysis to improve patient outcomes. We describe the mechanisms of various activation pathways during the interaction between blood and components of the ECC and describe approaches to mitigate the effects of these adverse interactions. The opportunities to develop improved dialysis membranes as well as implementation strategies with less potential for undesired biological reactions are discussed.

Choices in hemodialysis therapies: variants, personalized therapy and application of evidence-based medicine

The extent of removal of the uremic toxins in hemodialysis (HD) therapies depends primarily on the dialysis membrane characteristics and the solute transport mechanisms involved. While designation of ‘flux’ of membranes as well toxicity of compounds that need to be targeted for removal remain unresolved issues, the relative role, efficiency and utilization of solute removal principles to optimize HD treatment are better delineated. Through the combination and intensity of diffusive and convective removal forces, levels of concentrations of a broad spectrum of uremic toxins can be lowered significantly and successfully. Extended clinical experience as well as data from several clinical trials attest to the benefits of convection-based HD treatment modalities. However, the mode of delivery of HD can further enhance the effectiveness of therapies. Other than treatment time, frequency and location that offer clinical benefits and increase patient well-being, treatment- and patient-specific criteria may be tailored for the therapy delivered: electrolytic composition, dialysate buffer and concentration and choice of anticoagulating agent are crucial for dialysis tolerance and efficacy. Evidence-based medicine (EBM) relies on three tenets, i.e. clinical expertise (i.e. doctor), patient-centered values (i.e. patient) and relevant scientific evidence (i.e. science), that have deviated from their initial aim and summarized to scientific evidence, leading to tyranny of randomized controlled trials. One must recognize that practice patterns as shown by Dialysis Outcomes and Practice Patterns Study and personalization of HD care are the main driving force for improving outcomes. Based on a combination of the three pillars of EBM, and particularly on bedside patient–clinician interaction, we summarize what we have learned over the last 6 decades in terms of best practices to improve outcomes in HD patients. Management of initiation of dialysis, vascular access, preservation of kidney function, selection of biocompatible dialysers and use of dialysis fluids of high microbiological purity to restrict inflammation are just some of the approaches where clinical experience is vital in the absence of definitive scientific evidence. Further, HD adequacy needs to be considered as a broad and multitarget approach covering not just the dose of dialysis provided, but meeting individual patient needs (e.g. fluid volume, acid–base, blood pressure, bone disease metabolism control) through regular assessment—and adjustment—of a series of indicators of treatment efficiency. Finally, in whichever way new technologies (i.e. artificial intelligence, connected health) are embraced in the future to improve the delivery of dialysis, the human dimension of the patient–doctor interaction is irreplaceable. Kidney medicine should remain ‘an art’ and will never be just ‘a science’.

Informed decision-making in delivery of dialysis: combining clinical outcomes with sustainability

As the prevalence of chronic kidney disease is expected to rise worldwide over the next decades, provision of renal replacement therapy (RRT), will further challenge budgets of all healthcare systems. Most patients today requiring RRT are treated with haemodialysis (HD) therapy and are elderly. This article demonstrates the interdependence of clinical and sustainability criteria that need to be considered to prepare for the future challenges of delivering dialysis to all patients in need. Newer, more sustainable models of high-value care need to be devised, whereby delivery of dialysis is based on value-based healthcare (VBHC) principles, i.e. improving patient outcomes while restricting costs. Essentially, this entails maximizing patient outcomes per amount of money spent or available. To bring such a meaningful change, revised strategies having the involvement of multiple stakeholders (i.e. patients, providers, payers and policymakers) need to be adopted. Although each stakeholder has a vested interest in the value agenda often with conflicting expectations and motivations (or motives) between each other, progress is only achieved if the multiple blocs of the delivery system are advanced as mutually reinforcing entities. Clinical considerations of delivery of dialysis need to be based on the entire patient disease pathway and evidence-based medicine, while the non-clinical sustainability criteria entail, in addition to economics, the societal and ecological implications of HD therapy. We discuss how selection of appropriate modes and features of delivery of HD (e.g. treatment modalities and schedules, selection of consumables, product life cycle assessment) could positively impact decision-making towards value-based renal care. Although the delivery of HD therapy is multifactorial and complex, applying cost-effectiveness analyses for the different HD modalities (conventional in-centre and home HD) can support in guiding payability (balance between clinical value and costs) for health systems. For a resource intensive therapy like HD, concerted and fully integrated care strategies need to be urgently implemented to cope with the global demand and burden of HD therapy.

The scientific principles and technological determinants of haemodialysis membranes

In most biological or industrial (including medical) separation processes, a membrane is a semipermeable barrier that allows or achieves selective transport between given compartments. In haemodialysis (HD), the semipermeable membrane is in a tubular geometry in the form of miniscule pipes (hollow fibres) and separation processes between compartments involve a complex array of scientific principles and factors that influence the quality of therapy a patient receives. Several conditions need to be met to accomplish the selective and desired removal of substances from blood in the inner cavity (lumen) of the hollow fibres and across the membrane wall into the larger open space surrounding each fibre. Current HD membranes have evolved and improved beyond measure from the experimental membranes available in the early developmental periods of dialysis. Today, the key functional determinants of dialysis membranes have been identified both in terms of their potential to remove uraemic retention solutes (termed ‘uraemic toxins’) as well subsidiary criteria they must additionally fulfill to avoid undesirable patient reactions or to ensure safety. The production of hundreds of millions of kilometres of hollow fibre membranes is truly a technological achievement to marvel, particularly in ensuring that the fibre dimensions of wall thickness and inner lumen diameter and controlled porosity—all so vital to core solute removal and detoxification functions of dialysis—are maintained for every centimetre length of the fragile fibres. Production of membranes will increase in parallel with the increase in the number of chronic kidney disease (CKD) patients expected to require HD therapies in the future. The provision of high-quality care entails detailed consideration of all aspects of dialysis membranes, as quality cannot in any way be compromised for the life-sustaining—like the natural membranes within all living organisms—function artificial dialysis membranes serve.

Screening for occult coronary artery disease in potential kidney transplant recipients: time for reappraisal?

Screening for occult coronary artery disease in potential kidney transplant recipients has become entrenched in current medical practice as the standard of care and is supported by national and international clinical guidelines. However, there is increasing and robust evidence that such an approach is out-dated, scientifically and conceptually flawed, ineffective, potentially directly harmful, discriminates against ethnic minorities and patients from more deprived socioeconomic backgrounds, and unfairly denies many patients access to potentially lifesaving and life-enhancing transplantation. Herein we review the available evidence in the light of recently published randomized controlled trials and major observational studies. We propose ways of moving the field forward to the overall benefit of patients with advanced kidney disease.

Multitargeted interventions to reduce dialysis-induced systemic stress

Hemodialysis (HD) is a life-sustaining therapy as well as an intermittent and repetitive stress condition for the patient. In ridding the blood of unwanted substances and excess fluid from the blood, the extracorporeal procedure simultaneously induces persistent physiological changes that adversely affect several organs. Dialysis patients experience this systemic stress condition usually thrice weekly and sometimes more frequently depending on the treatment schedule. Dialysis-induced systemic stress results from multifactorial components that include treatment schedule (i.e. modality, treatment time), hemodynamic management (i.e. ultrafiltration, weight loss), intensity of solute fluxes, osmotic and electrolytic shifts and interaction of blood with components of the extracorporeal circuit. Intradialytic morbidity (i.e. hypovolemia, intradialytic hypotension, hypoxia) is the clinical expression of this systemic stress that may act as a disease modifier, resulting in multiorgan injury and long-term morbidity. Thus, while lifesaving, HD exposes the patient to several systemic stressors, both hemodynamic and non-hemodynamic in origin. In addition, a combination of cardiocirculatory stress, greatly conditioned by the switch from hypervolemia to hypovolemia, hypoxemia and electrolyte changes may create pro-arrhythmogenic conditions. Moreover, contact of blood with components of the extracorporeal circuit directly activate circulating cells (i.e. macrophages-monocytes or platelets) and protein systems (i.e. coagulation, complement, contact phase kallikrein-kinin system), leading to induction of pro-inflammatory cytokines and resulting in chronic low-grade inflammation, further contributing to poor outcomes. The multifactorial, repetitive HD-induced stress that globally reduces tissue perfusion and oxygenation could have deleterious long-term consequences on the functionality of vital organs such as heart, brain, liver and kidney. In this article, we summarize the multisystemic pathophysiological consequences of the main circulatory stress factors. Strategies to mitigate their effects to provide more cardioprotective and personalized dialytic therapies are proposed to reduce the systemic burden of HD.

A Review of Commercial Developments and Recent Laboratory Research of Dialyzers and Membranes for Hemodialysis Application

Dialyzers have been commercially used for hemodialysis application since the 1950s, but progress in improving their efficiencies has never stopped over the decades. This article aims to provide an up-to-date review on the commercial developments and recent laboratory research of dialyzers for hemodialysis application and to discuss the technical aspects of dialyzer development, including hollow fiber membrane materials, dialyzer design, sterilization processes and flow simulation. The technical challenges of dialyzers are also highlighted in this review, which discusses the research areas that need to be prioritized to further improve the properties of dialyzers, such as flux, biocompatibility, flow distribution and urea clearance rate. We hope this review article can provide insights to researchers in developing/designing an ideal dialyzer that can bring the best hemodialysis treatment outcomes to kidney disease patients.

Serum phosphate and mortality in incident dialysis patients in Australia and New Zealand

AIM

Hyperphosphataemia is associated with increased adverse outcomes, including mortality. Re-examining this association using up-to-date data reflecting current and real-world practices, across different global regions and in both haemodialysis and peritoneal dialysis patients, is important.

METHODS

We describe the association between serum phosphate and all-cause and cardiovascular mortality in incident dialysis patients between 2008 and 2018 using the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry. Time-dependent Cox proportionate hazards models were used. Models were adjusted for available covariates and fitted for the overall cohort, and also each dialysis modality.

RESULTS

31 989 patients were followed over 97 122 person-years at risk (mean age at first dialysis 61 years, 38% female, 67% haemodialysis). We observed a U-shaped association between serum phosphate and all-cause mortality. In the fully adjusted model, categories of serum phosphate above and below 1.25-1.99 mmol/L were associated with progressively higher risk, reaching a hazard ratio of 2.13 (95% CI 1.93-2.36, p < .001) for serum phosphate ≥2.75 mmol/L, and 1.56 (95% CI 1.44-1.69, p < .001) for serum phosphate <1.00 mmol/L. Low and high levels of serum phosphate were also associated with increased risk of cardiovascular mortality, however the association with high serum phosphate was more pronounced ("J-shaped relationship"). The associations were consistent across sub-analyses of patients receiving haemodialysis and peritoneal dialysis treatment.

CONCLUSION

In this large contemporary dialysis cohort, both high and low levels of serum phosphate were independently associated with increased risk of mortality. Future studies are required to determine whether treatment of abnormal serum phosphate levels improves mortality.

Dialyzer Performance During Hemodialysis Without Systemic Anticoagulation Using a Heparin-Grafted Dialyzer Combined With a Citrate-Enriched Dialysate: Results of the Randomized Crossover Noninferiority EvoCit Study

RATIONALE & OBJECTIVE

The EvoCit study was designed to evaluate performance of a heparin-grafted dialyzer during hemodialysis with and without systemic anticoagulation.

STUDY DESIGN

Randomized, crossover, noninferiority trial. Noninferiority was defined as a difference of≤10% for the primary outcome.

SETTING & PARTICIPANTS

Single hemodialysis center; 26 prevalent patients treated with 617 hemodialysis sessions.

INTERVENTIONS

Hemodialysis using a heparin-grafted dialyzer combined with a 1.0mmol/L citrate-enriched dialysate ("EvoCit") without systemic anticoagulation compared with hemodialysis performed with a heparin-grafted dialyzer with systemic heparin ("EvoHep"). Patients were randomly allocated to a first period of 4 weeks and crossed over to the alternative strategy for a second period of 4 weeks.

OUTCOMES

The primary end point was the difference in Kt/V_urea between EvoCit and EvoHep. Secondary end points were urea reduction ratio, middle molecule removal, treatment time, thrombin generation, and reduction in dialyzer blood compartment volume.

RESULTS

The estimated difference in Kt/V_urea between EvoCit and EvoHep was-0.03 (95% CI, -0.06 to-0.007), establishing noninferiority with mean Kt/V_urea of 1.47±0.05 (SE) for EvoCit and 1.50±0.05 for EvoHep. Noninferiority was also established for reduction ratios of urea and β₂-microglobulin. Premature discontinuation of dialysis was required for 4.2% of sessions among 6 patients during EvoCit and no sessions during EvoHep. Effective treatment time was 236±5 minutes for EvoCit and 238±1 minutes for EvoHep. Thrombin generation was increased and there was greater reduction in dialyzer blood compartment volume after treatments with EvoCit compared with EvoHep.

LIMITATIONS

The effects of avoiding systemic anticoagulation on clinical outcomes were not evaluated.

CONCLUSIONS

EvoCit is noninferior to EvoHep with respect to solute clearance but results in a greater number of shortened treatments, more membrane clotting, and greater thrombin generation TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT03887468.

Advances in Kidney Replacement Therapy in Infants

Acute kidney injury continues to be a highly occurring disease in the intensive care unit, specifically affecting up to a third of critically ill neonates as per various studies. Although first-line treatments of acute kidney injury are noninvasive, kidney replacement therapy (KRT) is indicated when conservative management modes fail. There are various modalities of KRT which can be used for neonatal populations, including peritoneal dialysis, hemodialysis, and continuous KRT. However, these KRT modalities present their own challenges in this specific patient population Thus, it is the aim of this review to introduce each of these KRT modalities in terms of their challenges, advances, and future directions, with specific emphasis on new technology including the Cardio-Renal Pediatric Emergency Dialysis Machine, Newcastle infant dialysis and ultrafiltration system, and the Aquadex system for ultrafiltration.

Heparin locks with low and high concentration in haemodialysis patients: A systematic review and meta-analysis

AIM

There is no evidence-based consensus on the optimal concentration for heparin locks; several randomized controlled trials (RCTs) have evaluated the concentration of heparin locks, yet the results remain inconsistent. We aimed to assess heparin locks with low and high concentration in haemodialysis patients.

METHODS

We performed a systematic review and meta-analysis of RCTs focusing on the concentration in heparin locks. Studies were identified by searching PUBMED, EMBASE, Science Direct, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure (CNKI) and Wanfang databases (from inception to 15 March 2020). Summary risk ratios or mean differences with 95% confidence interval were calculated.

RESULTS

A total of 370 patients with four RCTs were included. Heparin locks with 1000 U/ml could significantly reduce the activated partial thromboplastin time (APTT) compared with 5000 U/ml. No significant differences were seen in the occurrence of catheter-related thrombosis, the length of catheter stay, the rates of bleeding and catheter occlusions between the two groups.

CONCLUSIONS

Lower concentrations in heparin lock are optimal for shortening APTT in haemodialysis patients; further studies are needed to elucidate the role of heparin concentration in the lock practice.

Dialysis-Induced Cardiovascular and Multiorgan Morbidity

Hemodialysis has saved many lives, albeit with significant residual mortality. Although poor outcomes may reflect advanced age and comorbid conditions, hemodialysis per se may harm patients, contributing to morbidity and perhaps mortality. Systemic circulatory "stress" resulting from hemodialysis treatment schedule may act as a disease modifier, resulting in a multiorgan injury superimposed on preexistent comorbidities. New functional intradialytic imaging (i.e., echocardiography, cardiac magnetic resonance imaging [MRI]) and kinetic of specific cardiac biomarkers (i.e., Troponin I) have clearly documented this additional source of end-organ damage. In this context, several factors resulting from patient-hemodialysis interaction and/or patient management have been identified. Intradialytic hypovolemia, hypotensive episodes, hypoxemia, solutes, and electrolyte fluxes as well as cardiac arrhythmias are among the contributing factors to systemic circulatory stress that are induced by hemodialysis. Additionally, these factors contribute to patients' symptom burden, impair cognitive function, and finally have a negative impact on patients' perception and quality of life. In this review, we summarize the adverse systemic effects of current intermittent hemodialysis therapy, their pathophysiologic consequences, review the evidence for interventions that are cardioprotective, and explore new approaches that may further reduce the systemic burden of hemodialysis. These include improved biocompatible materials, smart dialysis machines that automatically may control the fluxes of solutes and electrolytes, volume and hemodynamic control, health trackers, and potentially disruptive technologies facilitating a more personalized medicine approach.