Peritoneal dialysis has optimal intradialytic hemodynamics and preserves residual renal function: Why isn't it better than hemodialysis?

Comparison of soluble suppression of tumorigenicity 2 and brachial hemodynamic parameters between dialysis modalities in patients with end-stage kidney disease

PURPOSE

Major cardiovascular events (MACE) are the leading cause of mortality in patients with chronic kidney disease. Although hemodialysis (HD) and peritoneal dialysis (PD) are comparable in survival, patients with HD have a significantly higher risk of developing MACE. Soluble suppression of tumorigenicity 2 (sST2) is a cardiac biomarker, that does not vary with age, gender, and kidney function. This study aimed to compare arterial stiffness, fluid status, and sST2 levels, between patients with PD and those with in-center HD.

METHODS

This was a cross-sectional study, which was conducted with 36 PD patients, 36 HD patients, and 36 age, and gender-matched healthy controls. We used noninvasive methods for the assessment of arterial stiffness and fluid status.

RESULTS

The patients with PD overhydrated compared to HD patients and healthy control (p < 0.001, and p = 0.05, respectively). Patients with PD had higher central systolic blood pressure and central pulse pressure than patients with HD and the control group (p = 0.004, and p = 0.01; p < 0.001, and p = 0.004, respectively). HD patients had a significantly higher level of plasma sST2 level compared to PD patients and the control group (p = 0.03, and p = 0.005). HD as maintenance dialysis modality and dialysis vintage was associated with higher plasma sST2 concentration, and having a residual renal function in dialysis patients was related to the lower plasma sST2 concentration.

CONCLUSION

PD is associated with better sST2 levels even though higher volume load than HD. In addition, the loss of RRF may be the most important factor related to increased sST2.

Effect of Dialysis Modalities on All-Cause Mortality and Cardiovascular Mortality in End-Stage Kidney Disease: A Taiwan Renal Registry Data System (TWRDS) 2005-2012 Study

Introduction: End-stage kidney disease (ESKD) patients who need renal replacement therapy need to face a dialysis modality decision: the choice between hemodialysis (HD) and peritoneal dialysis (PD). Although the global differences in HD/PD penetration are affected by health-care policies, these two modalities may exert different effects on survival in patients with ESKD. Although Taiwan did not implicate PD as first policy, we still need to compare patients’ outcomes using two modalities in a nation-wise database to determine future patients’ care and health policies. Methods: We used the nationwide Taiwan Renal Registry Data System (TWRDS) database from 2005 to 2012 and included 52,900 patients (48,371 on HD and 4529 on PD) to determine all-cause and cardiovascular mortality among ESKD patients. Results: Age-matched survival probability from all-cause mortality was significantly lower in patients on PD than in those on HD (p < 0.05). The adjusted hazard ratios of 3-year and 5-year all-cause and cardiovascular mortality were significantly higher in PD compared with HD. The presence of comorbid conditions including myocardial infarction, coronary artery disease (CAD), diabetes mellitus (DM), hypoalbuminemia, hyperferritinemia and hypophosphatemia was related with significantly higher all-cause and CV mortality in PD patients. No significant difference was noted among younger patients <45 years of age regardless of DM and/or comorbid conditions. Conclusion: Although PD did not have the survival advantage compared to HD in all dialysis populations, PD was related with superior survival in younger non-DM patients, regardless of the presence of comorbidities. Similarly, for younger ESKD patients without the risk of CV disease, both PD and HD would be suitable dialysis modalities.

Association between hypomagnesemia and mortality among dialysis patients: a systematic review and meta-analysis

Background

Malnutrition-inflammation-atherosclerosis (MIA) syndrome is caused by the inflammatory cytokines in end stage renal disease (ESRD) patients, and MIA complex-related factors may be associated with hypomagnesemia and mortality. However, the association between serum magnesium level and mortality for dialysis patients is still not clear. Additionally, no meta-analysis has investigated the impact of serum magnesium on peritoneal dialysis and hemodialysis, separately.

Methods

We searched published studies in PubMed, Embase, Cochrane, Collaboration Central Register of Controlled Clinical Trials, and Cochrane Systematic Reviews through April 2022. Studies associated with serum magnesium and all-cause mortality or cardiovascular (CV) mortality in ESRD on kidney replacement therapy (KRT) patients were included. A hazard ratio (HR) with 95% confidence intervals (CI) was used to report the outcomes.

Results

Twenty-one studies involving 55,232 patients were included. Overall, there was a significant association between hypomagnesemia and all-cause mortality for dialysis patients (HR: 1.67, 95% CI [1.412-2.00], p < 0.001; certainty of evidence: moderate) using a mixed unadjusted and adjusted HR for analysis. There was also a significantly increased risk of CV mortality for individuals with hypomagnesemia compared with the non-hypomagnesemia group (HR 1.56, 95% CI [1.08-2.25], p < 0.001; certainty of evidence: moderate). In addition, a subgroup analysis demonstrated that hypomagnesemia was associated with a high risk of both all-cause mortality and CV mortality (all-cause mortality, HR:1.80, 95% CI [1.48-2.19]; CV mortality, HR:1.84, 95% CI [1.10-3.07]) in hemodialysis (HD) patients, but not in participants receiving peritoneal dialysis (PD; all-cause mortality, HR:1.26, 95% CI [0.84-1.91]; CV mortality, HR:0.66, 95% CI [0.22-2.00]). The systematic review protocol was prespecified and registered in PROSPERO [CRD42021256187].

Conclusions

Hypomagnesemia may be a significant risk factor for all-cause mortality and CV mortality in KRT patients, especially in those receiving hemodialysis. However, because of the limited certainty of evidence, more studies are required to investigate this association.

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.

Implantation of a peritoneal dialysis catheter in patients with ESRD using local anesthesia and Remifentanil

Study objective

The main objective of this study is to test the feasibility of the local anesthetic (LA) Mepivacaine 1% and sedation with Remifentanil as the primary anesthetic technique for the insertion of a peritoneal dialysis (PD) catheter, without the need to convert to general anesthesia.

Methods

We analyzed 27 consecutive end-stage renal disease (ESRD) patients who underwent the placement of a peritoneal catheter at our center between March 2015 and January 2019. The procedures were all performed by a general or vascular surgeon, and the postoperative care and follow-up were all conducted by the same peritoneal dialysis team.

Results

All of the 27 subjects successfully underwent the procedure without the need of conversion to general anesthesia. The catheter was deemed prone to usage in all patients and was found to be leak-proof in 100% of the patients.

Conclusion

This study describes a safe and successful approach for insertion of a PD catheter by combined infiltration of the local anesthetic Mepivacaine 1% and sedation with Remifentanil. Hereby, ESRD patients can be treated without general anesthesia, while ensuring functionality of the PD catheter.

Sulodexide Prevents Peritoneal Fibrosis by Downregulating the Expression of TGF-β1 and Its Signaling Pathway Molecules

Peritoneal dialysis is one of the main renal replacement treatments. However, long-term peritoneal dialysis keeps the peritoneum in contact with the sugar-containing nonphysiological peritoneal fluid, which leads to recurrent peritonitis, peritoneal fibrosis, and failure of ultrafiltration. Transforming growth factor-β1 (TGF-β1), related cytokines, and inflammatory factors are closely related to peritoneal fibrosis. Sulodexide (SLX) is a new type of glycosaminoglycan preparation, which is involved in the formation of an anionic charge barrier and can maintain the selective permeability of vascular endothelial cells. In this study, the innovative analysis of SLX specifically prevents the process of peritoneal dialysis peritoneal fibrosis by downregulating the expression of TGF-β1 and its signaling pathway molecules. We randomly divided 30 rats into three groups. The blank control group received no treatment. The peritoneal dialysis model group was injected with 4.25% peritoneal dialysate (PDF) 20 ml daily, and the SLX group was injected with 4.25% PDF 20 ml + sulodexide (SLX) 20 mg/kg daily. After 8 weeks of dialysis, the rats were sacrificed, and the peritoneal function test was performed to determine the amount of glucose transport and ultrafiltration. The thickness of peritoneal per unit area was observed under high magnification. The level of inflammation in peritoneal tissue and the expression of TGF-β1/Smad were detected. The results showed that SLX can significantly improve peritoneal tissue thickening and inflammation, can downregulate the expression of TGF-β1, Smad2, Smad3, and Smad7 in peritoneal tissue, and improve the progression of peritoneal fibrosis.

Therapeutic Hypothermia Reduces Peritoneal Dialysis Induced Myocardial Blood Flow Heterogeneity and Arrhythmia

Background: Moderate therapeutic hypothermia (TH) is a well-recognized cardio-protective strategy. The instillation of fluid into the peritoneum provides an opportunity to deliver moderate hypothermia as primary prevention against cardiovascular events. We aimed to to investigate both cardiac perfusion consequences (overall blood flow and detailed assessment of perfusion heterogeneity) and subsequently simulate the associated arrhythmic risk for patients undergoing peritoneal dialysis (PD) induced TH. Methods: Patients underwent high resolution myocardial perfusion scanning using high resolution 256 slice CT scanning, at rest and with adenosine stress. The first visit using the patient's usual PD regimen, on the second visit the same regime was utilized but with cooled peritoneal dialysate at 32°C. Myocardial blood flow (MBF) was quantified from generated perfusion maps, reconstructed in 3D. MBF heterogeneity was assessed by fractal dimension (FD) measurement on the 3D left ventricular reconstruction. Arrhythmogenicity was quantified from a sophisticated computational simulation using a multi-scale human 3D ventricle wedge electrophysiological computational model. Results: We studied 7 PD patients, mean age of 60 ± 7 and mean vintage dialysis of 23.6 ± 17.6 months. There were no significant different in overall segmental MBF between normothermic condition (NT) and TH. MBF heterogeneity was significantly decreased (-14%, p = 0.03) at rest and after stress (-14%, p = 0.03) when cooling was applied. Computational simulation showed that TH allowed a normalization of action potential, QT duration and T wave. Conclusion: TH-PD results in moderate hypothermia leading to a reduction in perfusion heterogeneity and simulated risk of non-terminating malignant ventricular arrhythmias.

Predialysis and Dialysis Therapies Differently Affect Nitric Oxide Synthetic Pathway in Red Blood Cells from Uremic Patients: Focus on Peritoneal Dialysis

Red blood cells (RBCs) have been found to synthesize and release both nitric oxide (NO) and cyclic guanosine monophosphate (cGMP), contributing to systemic NO bioavailability. These RBC functions resulted impaired in chronic kidney disease (CKD). This study aimed to evaluate whether predialysis (conservative therapy, CT) and dialysis (peritoneal dialysis, PD; hemodialysis, HD) therapies used during CKD progression may differently affect NO-synthetic pathway in RBCs. Our data demonstrated that compared to PD, although endothelial-NO-synthase activation was similarly increased, HD and CT were associated to cGMP RBCs accumulation, caused by reduced activity of cGMP membrane transporter (MRP4). In parallel, plasma cGMP levels were increased by both CT and HD and they significantly decreased after hemodialysis, suggesting that this might be caused by reduced cGMP renal clearance. As conceivable, compared to healthy subjects, plasma nitrite levels were significantly reduced by HD and CT but not in patients on PD. Additionally, the increased carotid intima-media thickness (IMT) values did not reach the significance exclusively in patients on PD. Therefore, our results show that PD might better preserve the synthetic NO-pathway in CKD-erythrocytes. Whether this translates into a reduced development of uremic vascular complications requires further investigation.

Cardiovascular mortality in peritoneal dialysis: the impact of mineral disorders

Introduction:

Mineral and bone disorders (MBD) are associated with higher mortality in dialysis patients. The main guidelines related to the subject, Kidney Disease Outcomes Quality Initiative (KDOQI) and Kidney Disease: Improving Global Outcomes (KDIGO), were elaborated based on published information from hemodialysis participants. The aim of our study was to evaluate the impact of calcium (Ca), phosphorus (P), and parathyroid hormone (PTH) (according to guideline ranges from KDOQI and KDIGO) on the cardiovascular mortality of peritoneal dialysis (PD) patients.

Methods:

We used the BRAZPDII database, an observational multi-centric prospective study, which assessed participants on PD between December 2004 and January 2011. Amongst 9,905 participants included in this database, we analyzed 4424 participants who were on PD for at least 6 months. The appropriate confounding variables were entered into the model. Serum levels of Ca, P, and PTH were the variables of interest for the purposes of the current study.

Results:

We found a significant association between high P serum levels, categorized by KDOQI and KDIGO (P above 5.5 mg/dL), and cardiovascular survival (p < 0.01). Likewise, a compelling association was found between lower levels of PTH, categorized by guidelines (KDOQI and KDIGO - PTH less than 150 pg/mL, p < 0.01), and cardiovascular survival.

Conclusion:

In conclusion, levels of P above and PTH below the values proposed by KDOQI and KDIGO were associated with cardiovascular mortality in PD patients.

Aspectos clave en el mantenimiento de la diuresis residual en pauta de hemodiálisis incremental. Experiencia de diez años

Introducción: La hemodiálisis incremental o progresiva es una modalidad de inicio de hemodiálisis, basada en la diuresis residual y adaptada a las necesidades del paciente, poco extendida pese a sus potenciales beneficios. Para su correcto seguimiento es necesario establecer unas pautas específicas en cada sesión de hemodiálisis, que deben ser conocidas por el personal que atiende a estos pacientes de forma regular. Objetivo: analizar la evolución de los pacientes que han iniciado tratamiento renal sustitutivo con hemodiálisis incremental. Material y Método: Estudio observacional retrospectivo de pacientes incidentes en tratamiento renal sustitutivo mediante hemodiálisis incremental en nuestro centro en los últimos 10 años. Comparación de resultados basales y a los 12 meses de seguimiento. Resultados: En este periodo de tiempo se han incluido 49 pacientes en técnica de hemodiálisis incremental. Aunque la diuresis residual desciende en el primer año de 2030±600 ml/día a 1300±500 (p<0,05), ésta se mantiene por encima de un litro en la mayoría de los casos. El aclaramiento de urea también desciende de 5,7±1,6 ml/min a 3,4±1,6 ml/min al año (p<0,05). Conclusiones: Iniciar tratamiento renal sustitutivo con hemodiálisis incremental puede mantener más tiempo la diuresis residual, para eso es clave el conocimiento de la técnica y su correcto manejo durante las sesiones de diálisis.

Supine equilibration of extracellular fluid in peritoneal dialysis varies with intra-abdominal pressure

BACKGROUND

Increased intra-abdominal pressure (PIA) leads to venous congestion in splanchnic and adjoining circulations. The aim is to examine whether PIA in peritoneal dialysis (PD) affects the mobilization of extracellular fluid from the lower body in supine body position.

METHODS

Patients were studied during a regular peritoneal equilibration test (PET) in supine body position using multifrequency bioimpedance analysis to determine extracellular resistance and absolute volume overload (AVO) in wrist-to-ankle (W2A) as well as in ankle-to-ankle (A2A) configurations. Measurements were taken at baseline (T0) after draining the peritoneal cavity, at T1 shortly after filling with 2 L of standard dialysate, and at T2 before taking the 2 h PET samples. PIA was measured from the column height in the PD catheter. Extracellular resistance in the lower extremities (RL) was taken as half of the A2A resistance.

RESULTS

Eighteen patients (56 ± 15 years, 76 ± 21 kg, body mass index (BMI) 26.4 ± 7 kg/m², 13 men) were studied. After having assumed a supine body position for the duration of 17, 77, and 155 min, AVO continuously decreased from 1.6 ± 1.3 (T0) to 1.2 ± 1.5 (T1) and 1.0 ± 1.4 L (T2). RL significantly increased from 238 ± 57 (T0) to 254 ± 62 (T1) and 264 ± 67 Ohm (T2). This increase was negatively correlated to BMI and PIA measured at any time point, but not to net ultrafiltration volume.

CONCLUSIONS

Orthostatic fluid shifts from the lower limbs may take up to 2 h in supine PD patients, especially with high BMI and PIA because of venous congestion in splanchnic and adjoining circulations.

Recurrent pulseless electrical activity and cardiac arrest caused by baroreceptor failure following neck irradiation

Introduction

Baroreceptor damage and hypersensitivity can produce labile autonomic blood pressure control. Neck irradiation for malignancy is a well-known but under-recognised cause of baroreceptor failure.

Case presentation

We describe a dramatic delayed complication of neck irradiation treatment. Our patient developed recurrent unexplained hypotension and pulseless electrical activity cardiac arrest upon connection to intermittent haemodialysis, which he had previously tolerated uneventfully until exposure to radiotherapy.

Conclusion

No other cause was identified, and this case thus highlights baroreflex dysfunction as an important differential diagnosis in patients with profound hypotension.