Changes in peritoneal membrane after continuous ambulatory peritoneal dialysis--a histopathological study.

Peritoneal membrane changes in continuous ambulatory peritoneal dialysis (CAPD) patients have been widely described but poorly classified. Our aim was to identify the morphological changes occurring after CAPD treatment. To this end, 17 biopsies of parietal peritoneum (1 cm in diameter) were withdrawn at least 5 cm from the catheter entry hole and stained with Van Gieson, hematoxylin-eosin, trichrome, and some immunohistochemical stains: keratin, vimentin, CD34, CD20, CD4, CD8, desmin, and collagen IV. The morphology of mesothelium, vessels, and basement membrane (BM) of mesothelium and vessels, the presence of inflammatory cells, fibrin, and calcifications, and the distribution and thickness of submesothelial tissue were evaluated. Patients were divided into three groups according to the thickness of the sclerotic band replacing mesothelium: group 1, band up to 40 microns; group 2, band less than 40 microns; group 3, no sclerotic band. The main histopathological alterations noted were: loss of mesothelium; sclerotic alteration of vessels or duplication of BM; presence of myofibroblasts; and presence of inflammatory cells (sparse, focal, or perivascular), mainly represented by macrophages and CD4+ lymphocytes. No significant qualitative differences were observed between the three groups. In conclusion, the variable histological changes in peritoneal membrane suggest a routine peritoneal biopsy in any surgical procedure to better understand pathological changes in the course of CAPD treatment.

HIV infection in dialysis centers in Italy: a nationwide multicenter study.

The prevalence of HIV infection in dialysis populations varies according to different countries and geographic areas. We performed a nationwide epidemiological study by means of a questionnaire in the period from January 1990 to December 1995. Questions were about whether and which HIV tests were performed and which preventive measures were adopted. A separate survey evaluated the data the HIV-positive patients. Only 62% of the centers responded to the questionnaire, corresponding to 21,500 dialysis patients in 1990 and 27,000 in 1995. The prevalence of HIV-positive subjects was 0,13% for 1995. A total of 48 patients with HIV infection were identified: risk factors were drug abuse in 16 cases, homosexuality in 9, heterosexual contact in 8, transfusion in 7, renal transplant in 3 and unknown cause in 5. Forty-five patients were on hemodialysis, and 3 were receiving peritoneal dialysis. At follow-up, 19 patients died: infection and malnutrition were the most frequent causes of death. The death rate of patients who were already HIV positive when dialysis was started (group 1, 29 cases) was 19.36 deaths/1,000 patient/month. The correlations, performed only for group 1, showed a significantly worse prognosis for patients with CD4 < 200/mm3 and for those with AIDS. In conclusion, in Italy the prevalence of HIV infection in the dialysis population is low, and the outcome of HIV-positive patients in dialysis was found to be better than earlier literature reports. The use of chronic dialysis for HIV patients with uremia should not be discouraged.

Reduced blood levels of coagulation inhibitors in chronic hemodialysis compared with CAPD.

The aim of this study was to measure the coagulation inhibitors in two groups of uremic patients treated with hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) to evaluate the differences in anticoagulant activity. In 20 patients on HD and 20 on CAPD, mean age 66 +/- 8 and 58 +/- 14 years, respectively, the following parameters were determined between dialysis exchanges: protein C (PC), protein S (PS), antithrombin III (AT III), electrophoresis, prothrombin activation fragment (F1+2), alpha 1 antitripsin (alpha 1 AT), prothrombin time (PT), and activated partial thromboplastin time (PTT). The mean values of PC, PS, and AT III were respectively, 95.7 +/- 16 on HD and 92 +/- 23 on CAPD; 82.2 +/- 13.6 on HD and 90.5 +/- 13.6 on CAPD; the mean value F1+2 was 1.2 +/- 0.5 on HD and 1.04 +/- 0.5 on CAPD (p < 0.05). A good correlation between PS and AT III% functional activity (p < 0.03, r = 0.5) in both groups was found. More-over, PS functional activity was inversely correlated with duration of dialysis (p < 0.05, r = -0.3). HD patients showed a reduction of coagulation inhibitors compared with CAPD patients. Such a phenomenon could justify the increased thrombotic risk in HD patients. Since 80% of those on HD and only 20% of those on CAPD received erythropoietin (EPO), the prothrombotic state in HD could be due to reduced PS activity secondary to EPO treatment.

Cardiac output with CO2 rebreathing method in CAPD patients.

The aim of this study is to evaluate cardiac output (CO) with CO2 rebreathing method (RCO2) in patients (pts) on CAPD. We have studied 15 pts on CAPD from at least 6 months, the mean (+/- SD) age was 55 +/- 4 years, mean (+/- SD) hemoglobin was 10 +/- 2 gr/dl. The respiratory tests excluded obstructive or restrictive broncopneumopathies. Electrocardiograms and B-mode echocardiograms were normal. RCO2 was evaluated using the FICK formula: CO = VCO2/CvCO2 - CaCO2 where VCO2 is CO2 production; CvCO2 is the CO2 content in venous mixed blood; CACO2 is arterial CO2. VCO2 was obtained by collecting expired air into a Douglas bag during respiration at rest for 4 minutes. CvCO2 was obtained after 10-15 seconds of respiration in a mixture of 7% CO2 in O2. CaCO2 was obtained at CO2 end-tidal capnogram. RCO2 was performed in CAPD with full and empty abdomen. The mean (+/- SD) CO was 2.3 +/- 1.04 l/min with both full and empty abdomen, values below those theoretically calculated, taking into account the age and body surface (4.7 +/- 0.6 l/min P less than 0.0005). The reduction of CO is not induced by left ventricular insufficiency, but such phenomenon could be attributed to a redistribution of body fluid between intra and extracellular, in favour of the intracellular compartment. Therefore the increase in hematocrit and total plasma proteins can be fictitious.

Clearances and solutes extraction in biofiltration and hemodialysis with the AN 69 S.

Clearances and solutes extraction were assessed in biofiltration (BF) and in hemodialysis (HD) with the new polyacrylonitrile AN 69 S membrane. Three patients treated for three months by acetate dialysis (4 hours X 3) and subsequently by BF (3 hours X 3) were studied after achievement of steady state. Total intradepurative clearances (diffusive and convective) and solutes extraction of urea, creatinine, uric acid and phosphate were determined. Clearance of small molecular weight solutes was better in BF than in HD especially for uric acid and phosphate. This confirms the high depurative efficiency of the AN 69 S. BF gave better total clearances than HD, but the extraction of lower molecular weight solutes (due to the one-hour reduction of dialysis time) suggests that adequate treatment time is needed with this technique.