Identification of the Factors Associated With Intraperitoneal Pressure in ADPKD Patients Treated With Peritoneal Dialysis

Peritoneal Dialysis Care for People with Diabetes, Polycystic Kidney Disease, or Advanced Liver Disease

People treated with peritoneal dialysis (PD) often have complicating conditions that require careful management. Three such conditions are reviewed in this article-diabetes mellitus, polycystic kidney disease, and chronic liver disease. Each of these conditions requires an understanding of both its effect on the delivery of the PD and the effect of the PD on the condition itself. In diabetes, glucose absorption from the dialysate complicates metabolic control and affects salt and water management and patient outcome. There is particular benefit in clinical care being delivered through a multidisciplinary team that involves both kidney and diabetes experts. In relation to polycystic kidney disease, a key issue is the potential for increased intraperitoneal pressure due to the combined effect of the enlarged polycystic organs and the presence of the dialysis solution, and therefore, the PD prescription requires to be managed with a particular focus on limiting that pressure. For patients with liver disease, key issues include nutritional support because PD can add to protein losses already consequent on the liver disease itself. Considered approaches are required to manage ascites and reduce infection risk and the potential for hernias and leaks to develop. Mortality in this group is unfortunately high-however, PD may present a better management option than hemodialysis in many patients-particularly in those where the liver disease is complicated by low BP, clotting abnormalities, or troublesome ascites. Overall, the choice to use PD in patients with these complicating conditions should be based on shared decision making with the patient and their family members informed by high-quality information in which risks, benefits, and management strategies are clearly presented.

Pressure induces peritoneal fibrosis and inflammation through CD44 signaling

Peritoneal dialysis (PD) is a widely used sustainable kidney replacement therapy. Prolonged use of PD fluids is associated with mesothelial-mesenchymal transition, peritoneal fibrosis, and eventual ultrafiltration (UF) failure. However, the impact of pressure on the peritoneum remains unclear. In the present study, we hypothesized increased pressure is a potential contributing factor to peritoneal fibrosis and investigated the possible mechanisms. In vitro experiments found that pressurization led to a mesenchymal phenotype, the expression of fibrotic markers and inflammatory factors in human mesothelial MeT-5A cells. Pressure also increased cell proliferation and augmented cell migration potential in MeT-5A cells. The mouse PD model and human peritoneum equilibrium test (PET) data both showed a positive association between higher pressure and increased small solute transport, along with decreased net UF. Mechanistically, we found that significant upregulation of CD44 in mesothelial cells upon pressurization. Notably, the treatment of CD44 neutralizing antibodies prevented pressure-induced phenotypic changes in mesothelial cells, while a CD44 inhibitor oligo-fucoidan ameliorated pressure-induced peritoneal thickening, fibrosis, and inflammation in PD mice. To conclude, intraperitoneal pressure results in peritoneal fibrosis in PD via CD44-mediated mesothelial changes and inflammation. CD44 blockage can be utilized as a novel preventive approach for PD-related peritoneal fibrosis and UF failure.

Intra-abdominal pressure and residual renal function decline in peritoneal dialysis: a threshold-based investigation

BACKGROUND

The potential impact of elevated intra-abdominal pressure (IAP) on residual renal function (RRF) has not been determined. The objective of this study was to investigate the relationship between IAP and the rate of RRF decline in newly initiated peritoneal dialysis (PD) patients, and to identify the optimal IAP threshold value for delaying the deterioration of RRF.

METHODS

A cohort of 62 newly initiated PD patients who completed both 6- and 12-month follow-up evaluations was obtained using the Durand method. A logistic regression model was used to identify variables associated with a rapid decline in RRF. Receiver operating characteristic (ROC) curves were generated to determine the optimal threshold value. Another retrospective cohort analysis was performed to validate the identified critical value.

RESULTS

For each 1 cmH2O increase in IAP, the risk of a rapid decline in the RRF increased by a factor of 1.679. Subsequent analysis revealed that patients in the high IAP group had more significant decreases in residual renal estimated glomerular filtration rate (eGFR) (Z = -3.694, p < 0.001) and urine volume (Z = -3.121, p < 0.001) than did those in the non-high IAP group. Furthermore, an IAP ≥15.65 cmH2O was a robust discriminator for the prediction of the rate of RRF decline.

CONCLUSION

Patients in the high IAP group experienced a more rapid decline in RRF. Additionally, an optimal critical pressure of 15.65 cmH2O was identified for predicting the rate of RRF decline. IAP, as one of the factors contributing to the rapid decline in RRF in the first year of PD, should be given due attention.

Factors affecting intraperitoneal pressure (IPP) and its prognostic value in predicting leak risk and gastrointestinal symptoms in adult peritoneal dialysis patients: a systematic review and meta-analysis

BACKGROUND

Intraperitoneal pressure measurement offers therapeutic and prognostic benefits in predicting leak risks and gastrointestinal symptoms in Peritoneal Dialysis (PD) patients. This systematic review aims to evaluate the prognostic utility of intraperitoneal pressure measurements and different estimated intraperitoneal pressure equations in predicting the risk of non-infectious complications in PD patients.

METHODS

Databases including MEDLINE, EMBASE and Cochrane were searched up to July 2023. Randomised and non-randomised trials were included, focusing on End-Stage Kidney Disease (ESKD) patients undergoing PD. Primary outcomes were variables associated with intraperitoneal pressure, while secondary outcomes included PD-related non-infectious complications and gastrointestinal symptoms. Data synthesis combined meta-analysis with narrative synthesis. This review has been registered on PROSPERO (CRD42023475138).

RESULTS

Out of 1828 identified studies, 12 were included for systematic review and 10 for meta-analysis. Body Mass Index (BMI) and Body Surface Area (BSA) showed a consistent positive correlation with intraperitoneal pressure (BMI: r = 0.49, 95% CI 0.35-0.61, I2 = 67.39%, p = 0.003; BSA: r = 0.2, 95% CI 0.08-0.31, I2 = 14.10%, p = 0.324). Conversely, the association between intraperitoneal pressure and age, intraperitoneal volume, and Charlson Comorbidity Index were less consistent. Subgroup analysis demonstrated an association between higher intraperitoneal pressure in patients with increased BMI and BSA. However, the relationship between intraperitoneal pressure and non-infectious mechanical complications remained inconclusive.

DISCUSSION

This review underscores a significant association between intraperitoneal pressure and anthropometric measures (BMI and BSA). The majority of the studies identified included a small sample and considerable bias. However, the association between intraperitoneal pressure and clinically relevant outcomes was not clear.

CONCLUSIONS

While increasing body mass index and body surface areas are associated with increasing intraperitoneal pressure, the clinical relevance of measuring intraperitoneal pressure in an adult population remains unclear, particularly given the absence of an association with clinically relevant non-infectious outcomes.

The prognostic values of estimating intraperitoneal pressure in the occurrence of abdominal wall complications in peritoneal dialysis patients

BACKGROUND

Increased intraperitoneal pressure is associated with abdominal wall complications and technical failure of peritoneal dialysis (PD). Several equations have been developed to estimate intraperitoneal pressure. We aimed to assess the prognostic yield of the intraperitoneal pressure as estimated by current equations on the occurrence of abdominal wall complications in peritoneal dialysis patients.

METHODS

This is a retrospective analysis of data from a prospective cohort which recruited 1207 incident PD patients. Estimated intraperitoneal pressure was calculated using four available equations (according to Sigogne, Castellanos, Scanziani and de Jesus Ventura). Abdominal wall complications were recorded during follow-up. Univariate analysis and multivariate analysis with competing risk regression were used to assess the predictive power of the estimates of intraperitoneal pressure in the occurrence of abdominal wall complications.

RESULTS

During a median follow-up of 30 months, 66 (5.5%) patients (1.6/100 patient-years) developed abdominal wall complications. The median time to the occurrence of abdominal wall complications was 5.7 months. Only the estimated intraperitoneal pressure by the de Jesus Ventura equation significantly predicted abdominal wall complications by using univariate analyses. Associations between estimated intraperitoneal pressure by the de Jesus Ventura equation and the occurrence of abdominal wall complications disappeared after adjusting for significant clinical factors.

CONCLUSIONS

We verified the prognostic value of estimation of intraperitoneal pressure by four available equations in predicting abdominal wall complications in our single-center PD cohort. Due to a low diagnostic yield, a novel equation for estimating the intraperitoneal pressure is urgently needed.

Relationship between intraperitoneal pressure and the development of hernias in peritoneal dialysis: confirmation for the first time of a widely accepted concept

BACKGROUND

Intraperitoneal pressure (IPP) in peritoneal dialysis (PD) is an individual characteristic that can be modified by posture and intraperitoneal volume (IPV). It is considered one of the predisposing factors for complications in the abdominal wall, such as the appearance of hernias. No studies to date have confirmed this. The main aim of this study was to assess the relationship between the development of hernia in incident PD patients and IPP measured at PD onset.

METHODS

A prospective observational study of incident patients in a PD programme between 2010 and 2020. IPP was measured using the Durand's method.

RESULTS

One hundred and twenty-four incident patients on PD, 68% male, mean age 62.1 ± 15.23 years, body mass index (BMI) 27.7 ± 4.82 kg/m2, 44% were diabetic. IPP in supine was 16.6 ± 4.60 cm H2O for a mean IPV of 2047.1 ± 359.19 mL. Hernias were reported in 18.5% of patients during PD follow-up: 57% were inguinal hernias, 33% umbilical, and a further 10% presented in a combined form. PD hernias correlated positively with IPP in supine position (p = 0.037), patient age (p = 0.008), BMI (p = 0.043), a history of prior hernia (0.016), laparoscopic catheter placement (p = 0.026), and technique failure (p = 0.012). In the multivariate analysis, a higher IPP was independently related to the development of hernias (p = 0.028).

CONCLUSIONS

The development of hernias in PD was related to a higher IPP at PD onset, older age, higher BMI, history of prior hernia, catheter placement by laparoscopy, and technique failure.

Intraperitoneal pressure in peritoneal dialysis patients: a need for treatment individualization

High-quality and goal-directed peritoneal dialysis (PD) prescription should be provided to all PD patients. Prioritizing patients' goals is necessary for their quality of life, as it is assessment of volume and nutritional status, anemia and mineral and bone management, or small-solute removal. To optimize the removal of small solutes, and depending on membrane characteristics, the increase in concentration gradient difference or the increase in volume (recruitment of all peritoneal capacities) can be performed. Nevertheless, intraperitoneal volume should be tailored by measuring the intraperitoneal pressure (IPP) to avoid PD associated mechanical complications. In this editorial, a brief review on how IPP can be measured, and its implications are noted.

Novel equations for estimating intraperitoneal pressure among peritoneal dialysis patients

Background

Increased intraperitoneal pressure (IPP) is associated with abdominal wall complications and technical failure in peritoneal dialysis (PD). Since the standard measurement of IPP is limited due to its cumbersome procedures, we aimed to develop and validate equations for estimating IPP.

Methods

We performed a cross-sectional study with a total of 200 prevalent PD patients who were divided into development and validation datasets after random sampling matched by body mass index. The IPPs were measured using the Durand method, with whole-body and abdominal anthropometry indices collected. Equations with 2.0-L and 1.5-L fill volumes were generated by stepwise linear regression modelling. The bias, accuracy and precision of the estimated IPP (eIPP) with 2-L and 1.5-L fill volumes were compared with actual IPPs by the Durand method. The eIPP for the 2-L fill volume was also compared with other existing equations.

Results

Two new equations incorporating waist circumference and height from the decubitus plane to mid-axillary line were generated. The eIPPs exhibited small biases in relation to the Durand method , with median differences of -0.24 cmH2O and -0.10 cmH2O for 2 L and 1.5 L, respectively. The precisions evaluated by the standard deviation of the absolute value of the differences were 2.59 cmH2O and 2.50 cmH2O, respectively. The accuracies evaluated by the value of the percentage of estimates that differed by >20% for the eIPP were 26% for 2.0 L and 27% for 1.5 L. Better bias, precision and accuracy were observed for the eIPP equation compared with other existing equations for the 2.0-L fill volume.

Conclusions

We provided two new equations developed from abdominal anthropometry indices to accurately estimate the IPP in the PD population.

Physical activity and exercise in peritoneal dialysis: International Society for Peritoneal Dialysis and the Global Renal Exercise Network practice recommendations

Life participation requiring physical activity and physical function is a key patient-reported outcome for people receiving peritoneal dialysis (PD). Clinician guidance is required from multidisciplinary sources regarding exercise and activity advice to address the specific needs of this group. From August 2020 through to June 2021, the Global Renal Exercise Network and the International Society for Peritoneal Dialysis reviewed the published literature and international clinical experience to develop a set of clinical practice points. A set of questions relevant to physical activity and exercise were developed from the perspective of a person receiving PD and were the basis for the practice point development. The GRADE framework was used to evaluate the quality of evidence and to guide clinical practice points. The review of the literature found sparse quality evidence, and thus the clinical practice points are generally based on the expert consensus of people receiving PD, PD exercise expert clinicians and experienced PD exercise researchers. Clinical practice points address timing of exercise and activity (post-catheter insertion, peritoneal space empty or full), the uptake of specific activities (work, sex, swimming, core exercise), potential adverse outcomes related to activity and exercise (exit site care, perspiration, cardiovascular compromise, fatigue, intra-abdominal pressure), the effect of exercise and activity on conditions of interest (mental health, obesity, frailty, low fitness) and exercise nutrition.

Intraperitoneal pressure: Stability over time and validation of Durand's measurement method

Intraperitoneal pressure (IPP) is gaining consideration as a relevant parameter of peritoneal dialysis (PD) in adults, although many of its aspects are still pending clarification. We address here its stability over time and the validity of the usual method of clinical measurement, as proposed by Durand in 1992 but never specifically validated. We performed this validation by comparing Durand's method and direct measurements with a central venous pressure system. We performed a total of 250 measurement pairs in 50 patients with different intraperitoneal volumes plus in-vitro measurements with a simulated peritoneum. Absolute differences between the two systems in vivo were 0.87 ± 0.91 cmH₂O (range 0-5 cmH₂O); only 6.4% of them were ≥3 cmH₂O. In vitro results for both methods were identical. We also compared IPP measurements in the same patient separated by 1-4 h (514 measurement pairs in 136 patients), 1 week (92 pairs in 92 patients), and 2 years (34 pairs in 17 patients). Net differences of measurements separated by hours or 1 week were close to 0 cmH₂O, with oscillations of 1.5 cmH₂O in hours and 2.3 cmH₂O in 1 week. IPP measured 2 years apart presented a net decrease of 2.5 ± 4.9 cmH₂O, without correlation with body mass index changes or any other usual parameter of PD. In hours, 7% of IPP differences were >3 cmH₂O, 22% in 1 week, and 50% in 2 years. In conclusion, Durand's method is precise enough to measure IPP in peritoneal dialysis. This parameter is not stable over long timescales, so it is necessary to use recent measurements.