Longitudinal study of peritoneal membrane function in continuous ambulatory peritoneal dialysis: relationship with peritonitis and fibrosing factors.

BACKGROUND: The peritoneal equilibration test (PET) is a useful assessment of peritoneal function in continuous ambulatory peritoneal dialysis (CAPD) patients. However, the natural course of longitudinal change in peritoneal transport is not well defined. PATIENTS: We studied 105 unselected CAPD patients. Average age at enrollment was 50.7 +/- 11.3 years. METHODS: A PET was performed at enrollment. Peritoneal transport was expressed as dialysate-to-plasma creatinine ratio at 4 hours (DIP). Fibrosing factors and mesothelial cell markers, including TGFbeta, epidermal growth factor (EGF), platelet-derived growth factor (PDGF), hyaluronan, and cancer antigen 125 (CA125), were measured in overnight peritoneal dialysate effluent (PDE). Patients were followed for two years. Peritonitis episodes were recorded. Severe peritonitis was defined as an episode that required catheter removal or antibiotic therapy for more than 3 weeks. After two years, 75 patients were still alive and on CAPD. RESULTS: The PET was repeated in 64 patients, of whom 35 were male and 9 had diabetes. The change in D/P over two years was represented as AD/P. No significant change in peritoneal transport was seen after two years (D/P: 0.56 +/- 0.12 vs 0.55 +/- 0.13). A centripetal pattern of change in D/P was observed. The deltaD/P had normal distribution and was inversely correlated with D/P at baseline (r = -0.427, p < 0.005). Both results suggest a regression-to-mean phenomenon. The deltaD/P had no significant correlation with the total number of peritonitis episodes (Spearman r = 0.052, p = 0.74), but after severe peritonitis, affected patients had higher deltaD/P than patients who experienced no severe infection (0.040 +/- 0.136 vs -0.032 +/- 0.120, p < 0.05). For patients with no episodes of severe peritonitis (n = 47), deltaD/P was weakly correlated with baseline TGFbeta level (r = -0.506, p < 0.01). No correlation was seen between the levels of other fibrosing factors and change in peritoneal transport. CONCLUSIONS: Our findings suggest that the centripetal change of peritoneal transport probably reflects a regression-to-mean phenomenon. Peritoneal transport increases after severe peritonitis. The role of TGFbeta levels in PDE with regard to longitudinal change in peritoneal transport requires further study.     

Results of peritoneal equilibration test during treatment with polyglucose dialysis solution.

BACKGROUND: Results of peritoneal equilibration test (PET) suggest prolonged effect of polyglucose dialysis solution (PG-DS) on peritoneal permeability. OBJECTIVES: An evaluation of dialysate-to-plasma ratio (D/P) of urea, DIP creatinine, and D/D0 glucose (ratio of dialysate glucose at designated dwell time to dialysate glucose at 0 dwell time), and mass transfer area coefficients (KBD) of these solutes in PET before introduction, during administration, and after discontinuation of PG-DS hi patients treated with continuous ambulatory peritoneal dialysis (CAPD). DESIGN: Single-center prospective study with PG-DS; retrospective selection of the control group. SETTING: Peritoneal dialysis unit in a university hospital. PATIENTS: Fourteen patients (11 males; age 45.1 +/- 8.5 years) treated with CAPD for 17.5 +/- 9.9 months. 7.5% PG-DS was used for the overnight exchange. After discontinuation of the PG-DS, standard dialysis solutions, as previously used, were reintroduced. The control group was selected to match both CAPO duration and peritoneal permeability of the patients in the PG-DS group at the start of the study. METHODS: Standard PET was carried out at 1.6 +/- 0.8 months before the introduction of PG-DS (study period I, n = 14), after 1.2 +/- 0.6 months' use of PG-DS (study period II, n = 14), after 4.4 +/- 0.8 months' use of PG-DS (study period Ill, n = 11), after 8.8 +/- 2.2 months' use of PG-DS (study period IV, n = 9), and at 2.0 +/- 0.6 months after PG-DS discontinuation (study period V, n = 11). Patients in the control group underwent PET at similar time intervals (control periods I-V). RESULTS: In the PG-DS group, a tendency toward increased peritoneal permeability for urea and creatinine was shown during the consecutive study periods. D/D0 glucose was significantly higher only in the PET performed during use of PG-DS (periods II-IV) compared to results obtained in period I. In the control group, both D/P and KBD of both urea and creatinine remained unchanged, but K90 glucose was higher in the first 2 hours of the PET in control period V compared to respective values in control period III. CONCLUSION: Changes in peritoneal permeability are observed In CAPD patients treated with PG-DS. These changes may be at least partially related to the administration of polyglucose.     

Hepatic subcapsular steatosis as a complication associated with intraperitoneal insulin treatment in diabetic peritoneal dialysis patients.

OBJECTIVES: The aim of this study was to evaluate hepatic subcapsular steatosis (HSS) and its association with clinical parameters in nondiabetic continuous ambulatory peritoneal dialysis (CAPD) patients and in diabetic CAPD patients receiving intraperitoneal (IP) or subcutaneous (SC) insulin. DESIGN: Cross-sectional study. SETTING: A tertiary-care university hospital. PATIENTS: 28 CAPD patients (17 males and 11 females; mean age 53.5 +/- 14 years; mean CAPD duration 22.8 +/- 9 months) were included in the study. 14 patients had type II diabetes mellitus and 14 were nondiabetics. In the diabetic group, 8 patients were receiving IP insulin and 6 were receiving SC insulin. OUTCOME MEASURES: HSS was diagnosed on computed tomography without contrast administration. Other data collected were body mass index (BMI), weekly Kt/V, peritoneal equilibration test (PET) results, daily insulin dosage, duration of diabetes mellitus, duration of insulin treatment, dialysate glucose load, and serum findings for alanine aminotransferase, aspartate aminotransferase, albumin, and lipid profiles. RESULTS: HSS was detected in 5 of the 8 diabetics who were receiving IP insulin. None of the diabetics receiving SC insulin and none of the nondiabetic patients exhibited HSS. Daily insulin dosage [108 (95 - 108.5) vs 54 (36 - 72) U/day, p = 0.02], BMI [31 (30.5 - 36) vs 26.6 (26 - 30) kg/m2, p = 0.02], serum triglyceride level [194 (184 - 505) vs 69 (61 - 82) mg/dL, p = 0.04], and PET creatinine levels [D/P2 creat: 0.67 (0.54 - 0.74) vs 0.50 (0.50 - 0.56), p = 0.05; D/P4 creat: 0.75 (0.64 - 0.86) vs 0.60 (0.59 - 0.62), p = 0.02] were higher in diabetic patients receiving IP insulin who had HSS than in those who did not have HSS. PET glucose levels [D0/D2 glu: 0.40 (0.37 - 0.45) vs 0.50 (0.48 - 0.51), p = 0.03; D0/D4 glu: 0.36 (0.26 - 0.38) vs 0.44 (0.38 - 0.48), p = 0.04] were lower in diabetic patients receiving IP insulin who had HSS than in those who did not have HSS. CONCLUSIONS: Our results suggest that IP insulin plays a more important role in the pathogenesis of HSS than glucose levels in diabetic CAPD patients. They also indicate that HSS is associated with higher daily insulin requirement, obesity, hypertriglyceridemia, and high peritoneal transport rate in diabetic CAPD patients receiving IP insulin.     

Serum BNP concentration and left ventricular mass in CAPD and automated peritoneal dialysis patients.

OBJECTIVE: To compare ultrafiltration under continuous ambulatory peritoneal dialysis (CAPD) and automated PD (APD), disclosing potential effects on serum B-type natriuretic peptide (BNP) levels and echocardiographic findings. PATIENTS AND METHODS: This cross-sectional clinical study included 32 patients on CAPD and 30 patients on APD without clinical evidence of heart failure or hemodynamically significant valvular heart disease. Peritoneal equilibration tests, BNP levels, and echocardiographic measurements were performed in each subject. BNP measurements were also performed in 24 healthy control subjects. RESULTS: Patients on APD had lower ultrafiltration and higher values of BNP and left ventricular mass index (LVMI) compared with patients on CAPD (respectively: 775 +/- 160 vs 850 +/- 265 mL, p = 0.01; 253.23 +/- 81.64 vs 109.42 +/- 25.63 pg/mL, p = 0.001; 185.12 +/- 63.50 vs 129.30 +/- 40.95 g/m(2), p = 0.001). This occurred despite higher mean dialysate glucose concentrations and far more extensive use of icodextrin in the APD group. CONCLUSION: Treatment with APD is associated with higher plasma BNP levels and LVMI compared to CAPD. This may be the result of chronic fluid retention caused by lower ultrafiltration in APD patients.     

透析前腹膜微血管密度与腹膜基线溶质转运关系的研究

目的借助免疫组化技术,分析透析前腹膜微血管密度(腹膜透析置管术时)与腹膜基线溶质转运间的关系,以探究基线转运的可能形态学基础。方法入选首都医科大学附属北京友谊医院腹膜透析中心的新入非糖尿病持续不卧床腹膜透析患者。腹膜透析置管术时留取壁层腹膜标本,以CD34为血管内皮标志行免疫组化染色,显微镜下计数微血管密度(microvessel density,MVD)。开始透析4～6周后行标准腹膜平衡试验(peritoneal equilibration test.PET),计算存腹4h的肌酐腹腔引流液/血浆比值(D/Pcr),;前1日收集24h腹膜透析液,测定蛋白质总量(peritoneal protein excretion,PPE)。结果共纳入32例患者,以D/Pcr=0.65为界,分为高/高平均转运组(19例)和低/低平均转运组(13例)。研究期内无急性腹膜炎发作。在对体表面积、残余肾功能、平均动脉压、降压药使用情况、2.5%葡萄糖透析液使用频率、PET当天的血红蛋白、血浆C反应蛋白、白蛋白水平校正之后,前者腹膜MVD值显著高于后者(F=10.470,P=0.004);腹膜MVD值与D/Pcr呈显著正相关(r=0.432,P=0.035),但与PPE无显著相关性(r=0.079,P=0.683)。结论非糖尿病腹膜透析患者透析前腹膜MVD与其小分子溶质基线转运率正相关,与24h腹腔蛋白丢失量无关,可能蛋白质的漏出更多受制于微血管的内在通透性。     

Advanced glycosylation end-products in diabetic rats on peritoneal dialysis using various solutions.

OBJECTIVE: To evaluate and compare the effects of glucose-based solutions to those of icodextrin with respect to peritoneal transport characteristics and advanced glycosylation end-product (AGE) formation in the peritoneal membrane in a diabetic rat model of peritoneal dialysis (PD). DESIGN: Thirty-three male Sprague-Dawley rats weighing between 275-300 g were divided into five groups: group C (n = 6), control rats implanted with a catheter but not dialyzed; group D (n = 5), diabetic rats implanted with a catheter but not dialyzed; group G (n = 7), diabetic rats implanted with a catheter and dialyzed with standard 2.5% glucose solution for daytime exchanges and 4.25% glucose solution for overnight exchanges; group H (n = 8), diabetic rats implanted with a catheter and dialyzed with standard 2.5% glucose solution for daytime exchanges and 7.5% icodextrin solution for overnight exchanges; group I (n = 7), diabetic rats implanted with a catheter and dialyzed with 7.5% icodextrin solution for all exchanges. Dialysis exchanges (25 mL per exchange) were performed three times daily for a period of 12 weeks. Tissue sections were stained using a monoclonal anti-AGE antibody. One-hour peritoneal equilibration tests (PET) were performed every 4 weeks for comparison of transport characteristics. RESULTS: The level of immunostaining was lowest in group C and highest in group G. Significant differences in immunostaining were seen between group C and group G (p < 0.001), group C and group H (p = 0.001), and group C and group I (p < 0.05). Significant differences were also found between group G and group D (p < 0.05), and between group G and group I (p < 0.05). Over time, the ratio of glucose concentration after 1 hour to glucose concentration at instillation (D/D0) decreased and the dialysate-to-plasma ratio (D/P) of urea increased. Significant differences in D/D0 glucose and D/P urea were found between group C and group H (D/D0: 0.40 +/- 0.01 vs 0.35 +/- 0.01, p < 0.05; D/P urea: 0.87 +/- 0.03 vs 0.97 +/- 0.02, p < 0.05). CONCLUSIONS: These results suggest that AGE formation is lower with the use of peritoneal dialysis solution containing icodextrin than with glucose-based solution. We conclude that use of icodextrin may help to slow the deterioration of the peritoneal membrane, prolonging its use for dialysis.     

Intraperitoneal infusion of glucose-based dialysate in the rat--an animal model for the study of peritoneal advanced glycation end-products formation and effect on peritoneal transport.

OBJECTIVE: Glucose-based dialysate induces non enzymatic glycation within the peritoneal cavity. To evaluate the relationship between the formation of advanced glycation end-products (AGEs) and peritoneal transfer for small solutes and macromolecules, we developed a model of simulated peritoneal dialysis (PD) in normal rats. METHODS: Male albino rats of the Charles River strain were divided into two sets of 3 groups (15-25 rats in each group). In the experimental (E) group, the rats were intraperitoneally (i.p.) injected daily with a commercially available 4.25% dextrose solution. In the control puncture (CP) group, the peritoneum was punctured daily, but no PD solution infused. In an age-matched control (CC) group, no intervention was given. Two study protocols were used. Protocol A (duration 20 weeks) consisted of a daily i.p. injection of 10 mL PD solution per 100 g body weight. In protocol B, a double volume of PD solution was introduced (20 mL per 100 g body weight). At 9, 16, and 20 weeks in protocol A, and at 9 weeks in protocol B, urea, creatinine, microalbumin [(MAL) measured using specific anti-rat albumin monoclonal antibody], and AGEs (measured by fluorescent assay with excitation at 370 nm and emission at 440 nm) were measured in peritoneal effluent and serum. RESULTS: At no time during the study were AGEs detected in serum from any group in either protocol. In both protocols, no differences were found between the control groups (CP, CC) with respect to all parameters. In protocol A, the dialysate-to-plasma ratio (D/P) of urea was significantly higher in the experimental group as compared with the control groups at 9, 16, and 20 weeks [9 weeks: 0.59 +/- 0.03 (E) vs 0.39 +/- 0.02 (CP) vs 0.46 +/- 0.02 (CC), p < 0.0004 and p < 0.002, respectively; 16 weeks: 0.71 +/- 0.08 (E) vs 0.42 +/- 0.01 (CP) vs 0.46 +/- 0.01 (CC), p < 0.0001 and p < 0.02, respectively; 20 weeks: 0.57 +/- 0.03 (E) vs 0.39 +/- 0.01 (CP) vs 0.41 +/- 0.02 (CC), p < 0.002 and p < 0.004, respectively]. At 16 and 20 weeks, dialysate MAL levels were significantly increased in group E [16 weeks: 354.00 +/- 80.35 microg/mL (E) vs 134.75 +/- 14.36 microg/mL (CP) vs 110.69 +/- 7.83 microg/mL (CC), p < 0.04 and p < 0.03, respectively; 20 weeks: 283.17 +/- 14.71 microg/mL (E) vs 105.14 +/- 12.11 microg/mL (CP) vs 135.50 +/- 19.03 microg/mL (CC), p < 0.00001 and p < 0.0001, respectively]. In protocol B, at completion of the study (week 9), D/P urea, effluent MAL, and AGEs were significantly higher in the experimental group as compared with the control groups [D/P: 0.67 +/- 0.04 (E) vs 0.46 +/- 0.07 (CP) vs 0.41 +/- 0.02 (CC), p < 0.0002 and p < 00001, respectively; MAL: 336.8 +/- 63.30 microg/mL (E) vs 125.71 +/- 16.77 microg/mL (CP) vs 119.00 +/- 39.75 microg/mL (CC), p < 0.008 and p < 0.007, respectively; AGEs: 265.77 +/- 33.49 U/mg creatinine (E) vs 163.10 +/- 21.99 U/mg creatinine (CP) vs 83.17 +/- 22.66 U/mg creatinine (CC), p < 0.02 and p < 0.001, respectively]. Peritoneal effluent AGEs were found to be significantly correlated with D/P urea and dialysate MAL (r = 0.42, p < 0.04, and r = 0.7, p = 0.00001, respectively). CONCLUSIONS: In situ generation of AGEs constitutes the chief origin of peritoneal AGEs. Advanced glycation end-products affect peritoneal permselectivity for both small and large solutes. The rat model of simulated peritoneal dialysis developed in this experiment provides a reliable method for studying peritoneal AGE formation and effect on peritoneal transfer of small solutes and macromolecules.     

A comparison of outcomes between diabetic and nondiabetic CAPD patients in India

BACKGROUND: Continuous ambulatory peritoneal dialysis (CAPD) has been an established modality of renal replacement therapy in India for a decade, but there is a paucity of published data on the outcome of CAPD patients in India. We analyzed our data to determine the overall predictors of survival and compared patient survival between diabetic and nondiabetic end-stage renal disease patients on CAPD. METHODS: Of 373 patients, 197 were diabetic (165 males, 32 females) and 176 nondiabetic (104 males, 72 females). Patients were followed for 22 +/- 14 patient-months. Patients were prospectively followed until the study end point or death. RESULTS: Overall median survival was 48 patient-months. Median survival of diabetics (34.5 patient-months) was significantly inferior to nondiabetic patients (59 patient-months) p = 0.001. Overall patient survival at 1, 2, 3, 4, and 5 years was 90%, 72%, 60%, 49%, and 39%, respectively. Patient survival of diabetics versus nondiabetics at 1, 2, 3, 4, and 5 years was 85% versus 96%, 62% vs 82%, 48% vs 72%, 39% vs 62%, and 34% vs 42%, respectively. The relative risk of mortality in nondiabetics (34/176) was less than that in diabetic patients (71/197): odds ratio (OR) 0.43, 95% confidence interval (CI) 0.26 - 0.68; p = 0.001. On Cox regression analysis, diabetes (OR 1.95, 95% CI 1.23 - 3.07; p = 0.004), comorbidities (OR 0.39, 95% CI 0.25 - 0.61; p = 0.001), peritonitis (OR 1.79, 95% CI 1.19 - 2.68; p = 0.005), malnutrition (OR 0.52, 95% CI 0.29 - 0.94; p = 0.03), and residual glomerular filtration rate at initiation of CAPD (OR 0.87, 95% CI 0.81 - 0.93; p = 0.001) were significant predictors of overall mortality. Age (OR 0.68, 95% CI 0.45 - 1.03; p = 0.07), gender (OR 0.66, 95% CI 0.42 - 1.03; p = 0.06), and albumin level at initiation of CAPD (OR 0.92, 95% CI 0.64 - 1.33; p = 0.68) were not predictors of mortality. Age (56 +/- 10 vs 46 +/- 15 years, p = 0.001), comorbidities (51/197 vs 16/176, p = 0.001), peritonitis rate (0.68 vs 0.50 episodes/patient-year, p = 0.056), and severe malnutrition (27/197 vs 10/176, p = 0.002) were higher in diabetic than in nondiabetic patients. CONCLUSION: In India the majority of CAPD patients are diabetic. Patient survival was inferior in diabetic compared to nondiabetic patients on CAPD, but survival was statistically similar after adjustment for comorbidities. Diabetes, comorbidities, residual glomerular filtration rate, peritonitis, and severe malnutrition are predictors of mortality in CAPD patients.     

Impact of dialysis adequacy on cardiac function in pediatric CAPD patients.

BACKGROUND: Left ventricular hypertrophy is a major cause of morbidity and mortality among patients with chronic renal failure. Uremia-related risk factors play a fundamental role in its occurrence, thus better prognosis and prolonged survival can be attained by successful dialytic therapies. OBJECTIVE: To investigate whether dialysis adequacy has a beneficial effect on cardiac structure and function in children receiving continuous ambulatory peritoneal dialysis (CAPD). DESIGN: Cross-sectional study in the Pediatric Peritoneal Dialysis Unit of a university hospital. PATIENTS: Eighteen children, aged 13.3 +/- 2.8 years, being treated with CAPD, and 20 healthy age- and sex-matched control subjects were enrolled in this study. MAIN OUTCOME MEASURES: Echocardiographic evaluation was performed in all subjects. Dialysis adequacy indices [weekly urea (Kt/V) and creatinine clearance (TCCr)] were calculated in the dialysis group. RESULTS: Interventricular septal thickness, left ventricular (LV) posterior wall thickness, LV mass index (LVMI), and LV end systolic and diastolic dimensions were all found to be significantly higher in the CAPD group compared to the control subjects (p < 0.01). Ejection fraction and fractional shortening of the LV were not significantly different between the two groups. Mean Kt/V was 2.02 +/- 0.71 and mean TCCr was 58 +/- 33 L/wk/1.73 m2. There were significant negative correlations between dialysis adequacy indices and LV end systolic and diastolic dimensions (p < 0.05 and p < 0.001). Ejection fraction and fractional shortening were positively correlated with Kt/V (p < 0.01). Systolic and diastolic blood pressures were positively correlated with LVMI (r= 0.501 and r = 0.523). Significant inverse correlations between mean arterial pressure and both Kt/V and TCCr (r = -0.555 and r = -0.520) were detected. CONCLUSION: These data clearly document that cardiac structure and function are remarkably influenced by the uremic state and dialysis therapy in pediatric CAPD patients. The close relationships between echocardiographic findings and dialysis adequacy indices suggest that adequate dialysis has a beneficial effect on cardiac function via effective removal of toxic substances.     

The clinical usefulness of peritoneal dialysis fluids with neutral pH and low glucose degradation product concentration: an open randomized prospective trial

BACKGROUND: Long-term peritoneal dialysis (PD) is associated with the development of various structural and functional changes to the peritoneal membrane when bioincompatible conventional peritoneal dialysis fluids (PDFs) are used. In this study, we looked at patients that were treated with conventional PDFs and then changed to novel biocompatible PDFs with a neutral pH and a low concentration of glucose degradation products (GDPs) to investigate whether this change could result in the arrest or reversal of peritoneal membrane deterioration. METHODS: In an open label, randomized prospective trial, the clinical effects of conventional PDFs and biocompatible PDFs with neutral pH and very low concentration of GDPs were compared in 104 patients equally divided between both study PDFs. Blood and effluent dialysate samples, peritoneal equilibration tests, and adequacy evaluation were undertaken at baseline, 4, 8, and 12 months. The target variables were the ratio of dialysate-to-plasma (D/P) creatinine, peritoneal ultrafiltration, residual renal function, dialysis adequacy indices, and effluent cancer antigen 125 (CA125). RESULTS: D/P creatinine values were not different in the two groups. Peritoneal ultrafiltration was significantly higher in the low-GDP PDF group than in the conventional PDF group at all follow-up times (4 months: 9.1 +/- 4.3 vs 6.0 +/- 3.0; 8 months: 8.3 +/- 3.4 vs 6.0 +/- 3.0; 12 months: 8.9 +/- 3.3 vs 6.1 +/- 3.3 mL/g dextrose/day; p < 0.05). Peritoneal Kt/V urea values and total weekly Kt/V urea values at 4 months were significantly higher in the low-GDP PDF group than in the conventional PDF group. Residual renal function was not statistically significant. Effluent CA125 levels were significantly higher in the low-GDP PDF group at all follow-up visits (4 months: 37.8 +/- 20.8 vs 22.0 +/- 9.5; 8 months: 41.2 +/- 20.3 vs 25.9 +/- 11.3; 12 months: 40.4 +/- 21.4 vs 28.6 +/- 13.0 U/mL; p < 0.05). Among anuric patients, peritoneal ultrafiltration at 4, 8, and 12 months, total weekly Kt/V at 4 and 8 months, and CA125 levels at all follow-up visits were significantly higher in patients treated with low-GDP PDF than those treated with conventional PDF. However, among anuric patients, D/P creatinine showed no significant differences between the low-GDP PDF group and the conventional PDF group. CONCLUSION: The use of biocompatible PDFs with neutral pH and low GDP concentration can contribute to improvement of peritoneal ultrafiltration and peritoneal effluent CA125 level, an indicator of peritoneal membrane integrity in PD patients.     

Influence of plasticizer-free CAPD bags and tubings on serum, urine, and dialysate levels of phthalic acid esters in CAPD patients.

OBJECTIVES: To evaluate the impact of a plasticizer-free device on exposure to di-(2-ethylhexyl) phthalate (DEHP) and its major metabolites in patients on continuous ambulatory peritoneal dialysis (CAPD). DEHP is the most commonly used plasticizer in polyvinyl chloride (PVC) products; it is added to CAPD bags in order to improve the flexibility of the material. Since DEHP leaches out of the plastic matrix, patients on CAPD are exposed to considerable amounts of DEHP and its metabolites. DESIGN: A prospective cross-over study. SETTING: Department of nephrology in a teaching hospital. PARTICIPANTS: Six patients (4 female, 2 male) stable on peritoneal dialysis (PD) for at least 6 months. INTERVENTIONS: Patients were switched from a plasticizer-containing PVC CAPD system (A.N.D.Y. Plus, Fresenius Medical Care, Bad Homburg, Germany) to a polyolefine-made plasticizer-free system (stay-safe, Fresenius). MAIN OUTCOME MEASURES: Prior to and 42 days after the switch, 24-hour effluent dialysate and urine collections were performed and 10 mL blood was drawn. Concentrations of DEHP, mono-(2-ethylhexyl) phthalate (MEHP), phthalic acid (PA), and 2-ethylhexanol (2-EH) in urine, dialysate, and serum were determined using gas chromatography/mass spectrometry. RESULTS: Complete data were obtained from 5 patients. Serum levels of PA decreased significantly during the study period (0.137 +/- 0.078 mg/L vs 0.124 +/- 0.049 mg/L, p = 0.04), and the respective levels of DEHP decreased insignificantly (0.097 +/- 0.076 mg/L vs 0.069 +/- 0.046 mg/L, p = 0.07), whereas the concentrations of MEHP and 2-EH remained unchanged. Urine concentrations of PA were high (0.81 +/- 0.69 mg/L) but did not change substantially (0.70 +/- 0.50 mg/L). Effluent dialysate concentrations of MEHP and PA decreased significantly (0.0176 +/- 0.004 mg/L vs 0.0040 +/- 0.0007 mg/L, p = 0.043 and 0.158 +/- 0.056 mg/L vs 0.111 +/- 0.051 mg/L, p = 0.043, respectively). CONCLUSIONS: Although PD patients seem to be exposed to other sources of phthalates in addition to dialysis, use of plasticizer-free devices may help to reduce potentially immunosuppressive exposure to phthalate esters.     

Comparative study between intact PTH and fragments of PTH in patients on hemodialysis and CAPD.

Twenty-nine patients on hemodialysis (HD) and 29 patients on continuous ambulatory peritoneal dialysis (CAPD) were studied. Serum calcium and phosphorous levels were similar in the 2 groups. Serum parathyroid hormone (PTH) levels were determined by 4 different methods. Mid-molecule PTH levels were higher in HD (1099.5 +/- 876.8 pmol/L) than in CAPD patients (541.0 +/- 138.8 pmol/L), p less than 0.001, while intact PTH levels were similar. The ratio MM-PTH/Intact PTH was higher in HD (55.2 +/- 29.0) than in CAPD patients (39.0 +/- 20.0), where p less than 0.01. In patients with similar C-PTH, those on CAPD had higher levels of intact PTH (46.0 +/- 27.0 pmol/L) than those in HD (29.3 +/- 29.0 pmol/L), p less than 0.01. The ratio C-PTH/intact PTH was higher in HD (104.9 +/- 39.6) than in CAPD patients (59.3 +/- 32.3), p less than 0.001. The Peritoneal Saturation Index (PSI) of MM-PTH was 23.4 +/- 12%, and it showed a hyperbolic correlation in respect to MM-PTH serum levels. We concluded that CAPD can modify the plasma C-PTH and MM-PTH serum levels by peritoneal losses of these fragments.     

Independent effects of renal and peritoneal clearances on the mortality of peritoneal dialysis patients.

OBJECTIVE: Previous studies show that peritoneal Kt/V is an independent predictor of survival in anuric patients receiving continuous ambulatory peritoneal dialysis (CAPD). We studied whether peritoneal Kt/V has the same effect in CAPD patients with residual renal function. DESIGN: Observational cohort study. SETTING: Single dialysis center in a university teaching hospital. PATIENTS: New and prevalent CAPD patients. METHODS: We examined the 5-year follow-up results of our prospective study previously reported (Kidney Int 2000; 58:400-7). A total of 270 CAPD patients were followed for up to 6 years. Dialysis adequacy indices, residual renal function, and nutritional data were monitored. OUTCOME MEASURES: Primary outcomes included mortality and technique failure. Peritoneal Kt/V rather than total Kt/V was used for multivariate survival analysis. RESULTS: Average duration of follow-up was 35.1 +/- 22.0 months. Average peritoneal Kt/V throughout the study was 1.59 +/- 0.37; median residual glomerular filtration rate (GFR) 0.82 mL/minute. Five-year actuarial patient survival was 41.5%, and technique survival was 23.1%. Multivariate analysis showed that sex, age, duration of dialysis, presence of diabetes, serum albumin, dialysate-to-plasma creatinine ratio at 24 hours, peritoneal Kt/V, residual GFR, and normalized protein nitrogen appearance were independent factors of both actuarial patient survival and technique survival. For every 0.1 unit higher peritoneal Kt/V, relative mortality risk was 0.94 (95% Cl 0.89 - 0.99, p = 0.03). When prevalent and new CAPD cases were analyzed separately, peritoneal Kt/V predicted survival only for prevalent CAPD patients. CONCLUSION: We conclude that, in prevalent CAPD patients with relatively low levels of peritoneal clearance and residual renal function, a higher peritoneal Kt/V is associated with better survival. Peritoneal clearance below 1.6-1.7 likely has a major detrimental effect on the clinical outcome of CAPD patients with little residual renal function.     

QT dispersion and signal-averaged electrocardiogram in hemodialysis and CAPD patients.

OBJECTIVE: The aim of this study was to compare QT dispersion (QTd) and signal-averaged electrocardiogram (SA-ECG) parameters that may predict risk of malignant arrhythmias in patients on hemodialysis (HD), on continuous ambulatory peritoneal dialysis (CAPD), and in controls. SETTING: Controlled cross-sectional study in a tertiary-care setting. PATIENTS: 28 HD (M/F 18/10; mean age 32 +/- 9 years), 29 CAPD (M/F 17/12; mean age 34 +/- 10 years), and 29 healthy controls (M/F 17/12; mean age 32 +/- 8 years) were included. INTERVENTIONS: On ECG, minimum (QTmin) and maximum (QTmax) QT duration and their difference (QTd) were measured. In SA-ECG, duration of filtered QRS, HFLA signals less than 40 microV, and RMS voltage (40 ms) were also measured. RESULTS: Higher serum Ca2+ and lower K+ levels were found in CAPD compared to HD. All QT parameters were increased in HD and CAPD compared to controls. QT dispersion was significantly prolonged in HD compared to CAPD. In HD, QTd was correlated with left ventricular (LV) mass index (r = 0.53, p = 0.004), but not in CAPD (r = -0.09, p = 0.63). QT dispersion was significantly prolonged in patients with LV hypertrophy compared to patients without hypertrophy on HD (68 +/- 18 ms vs 49 +/- 18 ms, p = 0.008). In the analysis of SA-ECG, 3 of the 28 (11%) HD and 2 of the 29 (7%) CAPD patients had abnormal late potentials. Patients on HD and CAPD had significantly higher filtered-QRS duration compared to controls (105 +/- 15 ms and 104 +/- 12 ms vs 95 +/- 5 ms, respectively, p = 0.04). Patients with LV hypertrophy had higher filtered-QRS duration compared to patients without hypertrophy (109 +/- 12 ms vs 95 +/- 8 ms, p < 0.001). CONCLUSION: Dialysis patients had prolonged QTd and increased filtered-QRS duration in SA-ECG compared to controls. Patients on HD had longer QTd than patients on CAPD. QTd has been correlated to LV mass index in HD, but not in CAPD. This difference might be due to the effect of different dialysis modalities on electrolytes, especially the higher serum Ca2+ levels.     

CAPD患者腹膜电荷屏障与腹膜透析液蛋白质丢失的关系

目的测定持续非卧床腹膜透析（CAPD）患者腹膜电荷屏障,并对原发病为糖尿病肾病（DN）与慢性肾小球肾炎（CGN）的CAPD患者的腹膜电荷屏障以及腹膜透析液蛋白进行比较,进而探讨CAPD患者腹膜电荷屏障与腹膜透析液蛋白丢失的相关性。方法选择32例CAPD患者,收集血清以及腹膜透析液,采用清除法测定胰淀粉酶清除率（Cpam）以及唾液淀粉酶的清除率（Csam）的比值（Cpam/Csam）用以评价腹膜电荷屏障;同时测定腹膜透析液蛋白的丢失量。结果①32例CAPD患者腹膜Cpam/Csam的比值为（6.296±21.514）;腹膜透析液蛋白为（4.14±1.91）g;②CGN组腹膜透析液蛋白显著低于DN组[（4.35±1.88）g比（5.61±0.86）g,P=0.011〈0.05];而CGN组Cpam/Csam的比值显著高于DN组[（9.94±28.35）比（0.68±0.86）,P=0.017〈0.05]。③所有患者Cpam/Csam与腹膜透析液蛋白丢失量之间具有显著负相关,相关系数为-0.584,P〈0.01。而且其自然对数与腹膜透析液蛋白丢失量呈直线负相关。结论CAPD患者腹膜电荷屏障的丢失可增加腹膜透析液蛋白的漏出。     

Continuous ambulatory peritoneal dialysis is responsible for an increase in plasma norepinephrine.

OBJECTIVE: To investigate the reason for increasing norepinephrine (NE) levels reported in continuous ambulatory peritoneal dialysis (CAPD) patients. METHODS: Norepinephrine was measured in the plasma and peritoneal dialysate of CAPD patients (n = 22) and in the plasma and the urine of healthy subjects (n = 20). It was also measured in the plasma of patients with chronic renal failure (CRF) (n = 15) and patients on hemodialysis (HD) (n = 15). RESULTS: It was found that NE was increased in CAPD patients compared with healthy individuals (687+/-221 pg/mL vs 199+/-25 pg/mL, p < 0.01).The daily removal of NE from the peritoneum of CAPD patients was lower compared with the amount of NE excreted in the urine of healthy subjects. Plasma NE increased after infusion of peritoneal dialysate. In 15 new patients on CAPD, it was found that NE plasma levels increased from 329+/-67 pg/mL before initiation of dialysis, to 584+/-173 pg/mL after 12 months of treatment (p < 0.01). Finally, plasma NE in CAPD patients (687+/-221 pg/mL) was significantly higher compared with the already increased levels in patients on HD or with CRF (406+/-143 pg/mL and 378+/-142 pg/mL, respectively). CONCLUSIONS: It is concluded that CAPD in patients with end-stage renal disease is responsible for a progressive increase of plasma norepinephrine.     

Longitudinal study of proteins in plasma and dialysate during continuous ambulatory peritoneal dialysis (CAPD)

The aim was to evaluate plasma proteins during continuous ambulatory peritoneal dialysis (CAPD) in relation to dialysis losses, membrane permeability, renal insufficiency, and time on CAPD. Ten male patients, established on CAPD for at least 14 months, were studied every 8 weeks for 56 weeks. Blood and dialysate from the morning exchange were analysed for urea, creatinine, and 7 proteins, and used to calculate dialysate to plasma concentration ratios (D/P). These ratios were not significantly changed suggesting that permeability remained constant. However, there was a trend for beta 2-microglobulin, creatinine, and urea to increase progressively. After 56 weeks, beta 2-microglobulin had increased from 27.9 to 31.3 mg/L (p less than 0.05) and creatinine 1006 to 1099 mumoL/L (p less than 0.05) and both correlated with time on CAPD (p less than 0.001). Plasma alpha 1-acid glycoprotein, albumin, transferrin, IgG, IgA, and complement C3 were not significantly changed, although IgA and complement C3 were each negatively correlated with time on CAPD (r = -0.70 and -0.67, respectively), creatinine (r = 0.51 and -0.54), and urea (r = -0.61 and -0.61) (p less than 0.001 for all). It is concluded that increases in beta 2-microglobulin, creatinine, and urea are not due to loss of membrane permeability but reflect a slight increase in uraemia. Long-term decreases in immunological proteins may be caused by uraemia or progressive depletion.     

Peritoneal transport characteristics, comorbid diseases and survival in CAPD patients.

OBJECTIVE: To evaluate the influence of initial peritoneal transport rate, serum albumin concentration, and comorbid diseases on continuous ambulatory peritoneal dialysis (CAPD) patient survival. DESIGN: A prospective single-center study with a long-term follow-up. PATIENTS: A total of 213 consecutive CAPD patients, who underwent a peritoneal equilibration test (PET) at a mean of 7 days (range 3 - 30 days) after beginning CAPD, were included in this study. One hundred twenty patients were male, 116 patients had comorbid diseases, and mean age was 49.5 years (range 18 - 76 years). METHODS: A modified PET was performed using 4.25% glucose dialysis solution. Based on the dialysate-to-plasma creatinine concentration ratio at 4 hours' dwell (D4/P4 Cr, 0.62 +/- 0.14), patients were divided into high (H), high-average (HA), low-average (LA), or low (L) transporters. RESULTS: Of 213 patients, 16.9% were classified as H transporters, 30.5% as HA, 36.6% as LA, and 16.0% as L transporters. The H transporter group had a higher proportion of men, higher proportion of patients with comorbid diseases, lower initial serum albumin concentration, lower D4/D0 glucose, and lower drained volume. The initial D4/P4 Cr correlated with initial serum albumin (r= -0.35, p < 0.001). The patients with comorbid diseases had lower initial serum albumin and higher initial D4/P4 Cr. On Kaplan-Meier analysis, 2-year patient survival of group H was significantly lower compared to the other groups combined (57.1% vs 79.5%, p = 0.009). On Cox proportional hazards analysis, age, comorbid diseases, initial serum albumin concentration, and initial D4/P4 Cr were found to be independent risk factors for mortality. However, in the patients without comorbid diseases, patient survival was not different between group H and the other transport groups combined (p > 0.05), and only age was found to be an independent risk factor for mortality. CONCLUSION: These data suggest that a high peritoneal transport rate at initial PET is associated with high mortality, and that this is in part due to an increased prevalence of comorbid disease in H transporters. These H transporters with comorbid diseases represent a subset of patients with an especially poor prognosis. In patients without comorbid diseases, high transport status or low serum albumin concentration was not an independent risk factor for mortality.     

Association between gastric emptying rate and nutritional status in patients treated with continuous ambulatory peritoneal dialysis.

OBJECTIVE: To estimate gastric emptying rate in continuous ambulatory peritoneal dialysis (CAPD) patients, with or without indwelling dialysate, and to evaluate if there is an association between gastric motility and nutritional status. DESIGN: Single-center cross-sectional study. SETTING: Peritoneal Dialysis Unit, Medical Faculty, Jagiellonian University Hospital, Krakow, Poland. PATIENTS AND METHODS: 20 end-stage renal disease patients [11 F, 9 M; mean age 50.1 +/- 11 years; treated with CAPD for median 13.5 (2-61) months] were studied. All patients were nondiabetic and had no comorbidity that might influence gastric motility; nor were they receiving any prokinetic drugs. Gastric emptying rate was estimated with dynamic abdominal scintigraphy, started immediately after complete ingestion of a standard 200-kcal solid meal injected with 99mTc-labeled colloid, activity 40 MBq. Scintigraphy was performed at the rate of 23 images in 4-minute intervals for 92 minutes. Two consecutive procedures--with and without PD fluid--were performed at weekly intervals. As nutritional parameters, protein catabolic rate (PCR) and lean body mass (LBM) (based on urea and creatinine kinetics, respectively), body mass Index (BMI), and serum albumin were measured. RESULTS: All analyzed gastric emptying parameters, measured with or without dialysis fluid, were markedly prolonged in patients compared to values accepted as normal in the local scintigraphy unit. Gastric emptying half-time (T(1/2)) and percent of initial activity in minute 46 and in minute 92 were 60.5 +/- 25.0 minutes, 57.19% +/- 17.5%, and 33.8% +/- 20.9% with a full peritoneal cavity, and 63.9 +/- 28.2 minutes, 59.1% +/- 23.9%, and 33.9% +/- 24.3% with an empty peritoneal cavity. The T(1/2) and percent of initial activity after 46 and 92 minutes for healthy subjects were 39 +/- 9 minutes, 45% +/- 11%, and 15% +/- 6%, respectively. T(1/2) without dialysis fluid revealed a negative correlation with LBM and BMI values (r = -0.5, p < 0.05, and r = -0.56, p < 0.01; respectively). Patients with dialysate-free T(1/2) > 40 minutes were characterized by significantly lower serum albumin level compared to subjects with T(1/2) < 40 minutes (39.2 +/- 2.9 vs 42.9 +/- 3.6 g/L, p < 0.05). The values of all gastric emptying parameters measured for an empty abdomen were prolonged in subjects with BMI < 25 kg/m2. No difference was found between patients with and without PD fluid. CONCLUSIONS: Gastric emptying is markedly impaired in CAPD patients compared to healthy subjects. However, the presence of dialysate does not influence it significantly. Gastric emptying rate was negatively associated with the nutritional status of treated subjects. This association can be demonstrated when gastric motility is measured with an empty peritoneal cavity.     

Randomized, open label, controlled clinical trial of oral administration of an egg albumin-based protein supplement to patients on continuous ambulatory peritoneal dialysis.

BACKGROUND/AIM: Malnutrition is highly prevalent in patients on continuous ambulatory peritoneal dialysis (CAPD) and is a strong predictor of increased morbidity and mortality. Therefore, the aim of this study was to evaluate the effect of oral administration of an egg albumin-based protein supplement on the nutritional status of CAPD patients. METHODS: In this randomized, open label, controlled clinical trial, 28 CAPD patients were allocated to a study (n = 13) or a control (n = 15) group. Both groups received conventional nutritional counseling; the study group received, additionally, an oral egg albumin-based supplement. During a 6-month follow-up, all patients had monthly clinical and biochemical evaluations and quarterly assessments of adequacy of dialysis and nutrition. RESULTS: Serum albumin Levels were not different between groups; however, a significant increase (baseline vs final) was observed in the study group (2.64+/-0.35 vs 3.05+/-0.72 g/dL) but not in the control group (2.66+/-0.56 vs 2.80+/-0.54 mg/dL). Calorie and protein intake increased more in the study group (calories 1331+/-432 vs 1872+/-698 kcal; proteins 1.0+/-0.3 vs 1.7+/-0.7 g/kg) than in the control group (calories 1423+/-410 vs 1567+/-381 kcal; proteins 1.0+/-0.4 vs 1.0+/-0.3 g/kg). Similarly, non-protein nitrogen appearance rate (nPNA) increased significantly more in the study (1.00+/-0.23 vs 1.18+/-0.35 g/kg/day) than in the control group (0.91+/-0.11 vs 0.97+/-0.14 g/kg/ day). Triceps skinfold thickness (TSF) and midarm muscle area (MAMA) displayed a nonsignificant trend to a greater increase in the study group (TSF 16.7+/-8.7 vs 18.3+/-10.7 mm; MAMA 23.8+/-6.2 vs 25.8+/-5.9 cm2) than in controls (TSF 16.4+/-5.7 vs 16.9+/-7.0 mm; MAMA 28.7+/-7.8 vs 30.0+/-7.9 cm2). At the end of follow-up, the frequency of patients with moderate or severe malnutrition decreased 6% in the control group and decreased 28% in the study group. At the final evaluation, the most important predictors of serum albumin were the oral egg albumin-based supplement administration and protein intake (p < 0.05); secondary predictors (p = 0.06) were peritoneal transport rate and MAMA. CONCLUSIONS: In the study group, oral administration of the egg albumin-based supplement significantly improved serum albumin, calorie and protein intake, and nPNA, and, compared to controls, this maneuver was associated with a trend to increased anthropometric parameters and improved Subjective Global Assessment evaluation. Oral administration of the albumin supplement and protein intake were the most significant predictors of serum albumin at the end of follow-up. This oral supplement may be a safe, effective, and cheap method to improve nutritional status in peritoneal dialysis patients.