Rational Choice of Peritoneal Dialysis Catheter

The peritoneal catheter should be a permanent and safe access to the peritoneal cavity. Catheter-related problems are often the cause of permanent transfer to hemodialysis (HD) in up to 20% of peritoneal dialysis (PD) patients; in some cases, these problems require a temporary period on HD. Advances in connectology have reduced the incidence of peritonitis, and so catheter-related complications during PD have become a major concern.

In the last few years, novel techniques have emerged in the field of PD: new dialysis solutions, better connectology, and cyclers for automated PD. However, extracorporeal dialysis has continued to improve in terms of methods and patient survival, but PD has failed to do so. The main reason is that peritoneal access has remained problematical.

The peritoneal catheter is the major obstacle to widespread use of PD. Overcoming catheter-related problems means giving a real chance to development of the peritoneal technique. Catheters should be as efficient, safe, and acceptable as possible.

Since its introduction in the mid-1960s, the Tenckhoff catheter has not become obsolete: dozens of new models have been proposed, but none has significantly reduced the predominance of the first catheter. No convincing prospective data demonstrate the superiority of any peritoneal catheter, and so it seems that factors other than choice of catheter are what affect survival and complication rates. Efforts to improve peritoneal catheter survival and complication rates should probably focus on factors other than the choice of catheter. The present article provides an overview of the characteristics of the best-known peritoneal catheters.

Long QT, alteration of calcium-phosphate product, prevalence of ventricular arrhythmias and sudden death in peritoneal dialysis patients: a Holter study

Materials and methods We studied 79 patients on peritoneal dialysis. Each underwent 24-h electrocardiography (Holter monitoring) and measurement of the rate-corrected QT interval (QTc). We analyzed the correlation between QTc and plasma levels of Ca++, PO4−, K+, Na+, Mg++, and parathyroid hormone (PTH). Results The mean QTc was 0.445 ± 0.04 s. In 55 patients, the QTc was prolonged (> 0.45 s). Mean laboratory values for the group were: PTH 344 ± 25 pg/mL, Ca++ 9.27 ± 0.11 mg/dL, PO4− 5.5 ± 1.5 mg/dL, Na+ 139.6 ± 3.4 mmol/L, K+ 4.04 ± 0.64 mmol/L, and Mg++ 2.52 ± 0.43 mg/dL. Holter monitoring revealed complex premature ventricular contractions in 44 patients, monomorphic premature ventricular contractions in 16, and nonsustained ventricular tachycardia (NSVT) in 10. The QTc was significantly correlated with plasma levels of PO4− (r = 0.045, p < 0.05), PTH (r = 0.077, p < 0.02), and Ca++ (r = 0.076, p < 0.02). Eleven patients had Lown class 4a or 4b ventricular arrhythmias, and their mean QTc was 465 ± 0.02 ms. Ten had NSVT and their QTc was 464 ± 0.03 ms. Eleven patients died suddenly (mean QTc 465 ± 0.03 ms); all 11 had either NSTV or Lown class 4 ventricular arrhythmias. Conclusions Long QTc seems to be associated with an increased prevalence of ventricular arrhythmias that may be the cause of sudden cardiac death.

Abdominal aortic calcification is an independent predictor of cardiovascular events in peritoneal dialysis patients

Abdominal aortic calcification (AAC) is reported as a predictor for cardiovascular events in general population and in hemodialysis patients. At present, there are no AAC data in peritoneal dialysis. The purpose of this study was to evaluate the prognostic role of AAC score on cardiovascular events in peritoneal dialysis patients. Seventy-four peritoneal dialysis patients were enrolled. AAC was measured on baseline lateral abdomen radiographs by the semi-quantitative method as described by Kauppila. The other cardiovascular risk factors were obtained from patient history and blood examination. The Kaplan-Meier method was used to evaluate freedom from cardiovascular events, and differences were assessed with the log-rank statistic. Multivariate Cox regression models addressed time to cardiovascular events. The median period of follow-up was 30.5months (IQR 19.4-32.7). During follow-up, there were 29 cardiovascular events (39.2%). In univariable analysis, patient's age (HR=1.050; P=0.001), urine output (HR=0.999; P=0.02), and AAC stratified by tertiles (overall P-value<0.001) were significantly associated with cardiovascular events. In multivariable regression analysis, AAC score stratified by tertiles was the only independent predictor for cardiovascular events (overall P-value<0.001). To our knowledge, we have shown for the first time that AAC score is an independent predictor of cardiovascular events in peritoneal dialysis patients. Risk stratification by assessment of AAC score may provide important information for the management of cardiovascular disease in peritoneal dialysis patients without any additional expense, because these patients have several abdominal X-ray scans to evaluate the catheter position.

Advances in the technology of automated, tidal, and continuous flow peritoneal dialysis

Automated peritoneal dialysis (APD) has undergone substantial growth in recent years because of an increased demand for higher doses of peritoneal dialysis (PD) treatment and a need to improve quality of life for patients. The evolution of this treatment is closely linked with the development of new automatic machines and with recent advances in prescription and monitoring of PD treatment. In the present article, we describe the characteristics of the new generation of APD cyclers with particular regard to adequacy targets and safety. There is renewed interest in continuous-flow peritoneal dialysis (CFPD), because of a belief that new peritoneal access technologies will make the success of this modality a possibility. In the CFPD technique, a certain amount of fluid is constantly present in the abdomen, and constant inflow and outflow are maintained without interruption thanks to paired indwelling catheters. The PD solution is used either in a single pass or in a recirculation loop with a regeneration systems (sorbent cartridge or dialyzer).

Rational choice of peritoneal dialysis catheter

The peritoneal catheter should be a permanent and safe access to the peritoneal cavity. Catheter-related problems are often the cause of permanent transfer to hemodialysis (HD) in up to 20% of peritoneal dialysis (PD) patients; in some cases, these problems require a temporary period on HD. Advances in connectology have reduced the incidence of peritonitis, and so catheter-related complications during PD have become a major concern. In the last few years, novel techniques have emerged in the field of PD: new dialysis solutions, better connectology, and cyclers for automated PD. However, extracorporeal dialysis has continued to improve in terms of methods and patient survival, but PD has failed to do so. The main reason is that peritoneal access has remained problematical. The peritoneal catheter is the major obstacle to wide-spread use of PD. Overcoming catheter-related problems means giving a real chance to development of the peritoneal technique. Catheters should be as efficient, safe, and acceptable as possible. Since its introduction in the mid-1960s, the Tenckhoff catheter has not become obsolete: dozens of new models have been proposed, but none has significantly reduced the pre-dominance of the first catheter. No convincing prospective data demonstrate the superiority of any peritoneal catheter, and so it seems that factors other than choice of catheter are what affect survival and complication rates. Efforts to improve peritoneal catheter survival and complication rates should probably focus on factors other than the choice of catheter. The present article provides an overview of the characteristics of the best-known peritoneal catheters.

A new home based bioimpedance system for PD

Fluid overload and uncontrolled hypertension may be considered important mortality risk factors in peritoneal dialysis (PD) population. Even malnutrition is highly prevalent in PD patients. It is now well established that lower levels of serum markers of nutrition such as albumin, creatinine, and prealbumin are associated with increased mortality in PD patients [Fein, P.A. et al: Adv Perit Dial 2002;18:195-199]. Moreover cardiovascular disease is a leading cause of death in patients with end-stage renal disease, and hypertension and volume expansion are highly prevalent in long-term PD patients. Many studies in hemodialysis and in PD have demonstrated that phase sensitive bioelectrical impedance analysis is a widely used and proven method for evaluating patient's body composition. The vectorial bioimpedance analysis is a validated system to evaluate the hydration and nutritional state of hemodialysis and PD patients with acceptable sensitivity and specificity. The aim of this study is to evaluate the reliability and accuracy of the new multifrequency BodyComp bioimpedance analyzer as a home based tool versus traditional Bia Vector.

Integration of peritoneal dialysis in the treatment of uremia

The real integration of a specific therapy into the renal replacement program is represented by the possibility of easy and free patient transfer from one treatment to another without restrictions. In the case of peritoneal dialysis we feel that its integration in the therapeutic approach of uremia represents an ethical obligation for the physician, a clinical opportunity for the patient and a good cost/benefit solution for care givers. A full conviction that peritoneal dialysis represents a real therapeutic option for ESRD patients is necessary to achieve a real integration of this therapy in the uremia treatment program. A positive cost benefit ratio, both from the clinical and the economical points of view must also be seeked. The patient indirectly, must receive the same positive conviction, based on solid data and clinical results, comparable to those achievable in hemodialysis. Furthermore the patient must know that such treatment will provide an equal opportunity for kidney transplant compared to other therapies. Such a kind of feeling and knowledge must include information on patient's survival, rate of complications, treatment adequacy, availability of different techniques within the treatment and complete summary of advantages and disadvantages.

Evolution of technology for automated peritoneal dialysis

Automated peritoneal dialysis (APD) is important for the further penetration of PD in the dialysis marketplace. Long dwell, equilibration PD (CAPD) has limited applicability in many patients due to inadequate solute clearance or fast membrane transport characteristics. Providing large volumes of dialysate over circumscribed hours is highly labor intensive without an automated system. Early attempts at APD were crude but effective in reducing labor, which was generally provided by nursing staff. Later evolution of PD technology has been greatly accelerated by the microchip, and by miniaturization of components. Current generation machines allow individualized fill volumes, variable tidal volumes and additional daytime automated exchanges, teledialysis, memorized delivery control, and full portability. The ideal machine should not only be able to perform all treatment schedules, but it should also optimize the performance of a selected treatment strategy. Biocompatible solutions, improved osmotic agents, and sorbent technology are all adaptable to APD. The eventual evolution toward continuous flow PD will resolve many of the current problems with both CAPD and APD.