Imaging work-up for peritoneal access care and peritoneal dialysis complications.

Peritoneal dialysis (PD) represents a treatment opportunity for patients with end-stage renal failure, but it has particular complications that sometimes force cessation of this procedure (1- 9). These complications are due to the presence of the peritoneal catheter and of dialysis solution within the peritoneal cavity. Infections are the most common complications of PD, followed by mechanical complications. Diagnostic imaging of the complications of PD is important because such an evaluation can aid in the diagnosis and in the decision making process about the treatment. In this review we present the main radiologic investigations employed: plain radiograph, US, peritoneography, computed tomography peritoneography, magnetic resonance peritoneography, peritoneal scintigraphy. To diagnose catheter-related problems plain radiograph, ultrasonography and peritoneography can be useful. US is useful in diagnosing and following-up exit-site and tunnel infections. Peritoneography and CT-peritoneography, alone or in combination, can be recommended as gold standard investigation to assess mechanical peritoneal dialysis complications, such as catheter malfunction, leaks, hernias and sclerosing peritonitis. Newer methods, such as MR peritoneography or scintigraphy could be useful in selected patients, on center-based experience. An appropriate use of radiology may significantly improve technique survival, morbidity and mortality of patients treated with PD.

Hemoperitoneum in a continuous ambulatory peritoneal dialysis patient caused by a hepatocarcinoma treated with percutaneous embolization.

Hemoperitoneum is an infrequent but normally benign complication in continuous ambulatory peritoneal dialysis (CAPD) patients. It can occur at any time during peritoneal dialytic treatment. Hemoperitoneum is not associated with a specific disease and usually disappears spontaneously. In 20% of cases, however, hemoperitoneum is severe and requires specific investigation and emergency therapy. We report a case of hemoperitoneum in a 70-year-old, anti-hepatitic C virus-positive woman. After 48 months of CAPD treatment, a bloody peritoneal effluent developed, with severe anemia (hematocrit decreased from 30% to 20%). An abdominal computed tomography scan showed three hepatic lesions with signs of hepatic neoplasms; selective hepatic arteriography confirmed the diagnosis. Chemoembolization of the three lesions was performed, and hemoperitoneum disappeared within a few hours.

Continuous on-line determination of recirculation by thermodilution in hemodialysis patients.

The consistency of the determination of A-V fistula recirculation (R) using the thermodilution method (T) with a new probe (blood temperature monitor, BTM Fresenius A.G.) was studied in 32 patients (AVF: proximal 34%, distal 63%, graft 3%). We compared R calculated by T with both the traditional three-sample method (C) and the low-flow three-sample method (L); both BUN and creatinine (CR) were measured in all samples at the beginning and at the end of the session. T was also determined at the 2nd and 3rd hour. There was a significant correlation between T and either C or L at the start of the session (BUN and CR) as well as at the end (only CR). R was higher (11.9 +/- 10) in proximal AVF than in the distal (5 +/- 3.1%; p0.01) when measured by T at the same blood flow (QB: 313 +/- 45 vs 343 +/- 52 mls/min, p = ns). T increased but not significantly by increasing Qb from 150 to 300 mls/min in ten patients. No correlation was found during the session between blood pressure and T variations. In conclusion, T and L give very similar results while C overestimates recirculation. R is easy to perform repeteadly by T with results available online.

Residual renal function and nutritional parameters in CAPD.

In continuous ambulatory peritoneal dialysis (CAPD) residual renal function (RRF) plays an important role in the total amount of weekly clearances of small molecules. The purpose of this study was to determine if there were any differences in certain nutritional parameters between patients with and without RRF, total weekly clearance (KT/V) being equal. Therefore, we compared two groups of patients with equal weekly KT/V: group A without RRF [n = 7, KT/V 2.07 +/- 0.2) and group B with RRF (n = 7, KT/V 2.11 +/- 0.1, urea clearance 1.13 +/- 0.8, creatinine clearance 2.01 +/- 1.5 mL/min, contributing on the average of 15% (range 5.5%-28%) to the determination of KT/V]. The two groups were selected from 52 patients on CAPD for more than 9 months and they were comparable in age (A = 64.6 +/- 7 years, B = 64.1 +/- 7 years), duration of dialysis (A = 39.8 +/- 25 months, B = 36.3 +/- 31 months), body weight (A = 64 +/- 3.9 kg, B = 64.7 +/- 7.4 kg), and body mass index (A = 26.6 +/- 2.9, B = 25.8 +/- 3.6). The two groups turned out to be different in transferrin (A = 209 +/- 51, B = 278 +/- 24 mg/dL, p < 0.006), normalized protein catabolic rate (PCRN) (A = 0.87 +/- 0.07, B = 1.11 +/- 0.07 g/kg/day, p = 0.00), and albumin (A = 3.31 +/- 0.1, B = 3.55 +/- 0.2, p < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of calcitriol pulse therapy per os in CAPD patients.

Pulse calcitriol therapy (IV or per os) has been efficacious in hemodialysis (HD) patients to inhibit parathyroid hormone (PTH) levels, but there are very poor data for continuous ambulatory peritoneal dialysis (CAPD) patients. For this reason, we used calcitriol (C) per os (0.75-1.5 micrograms three times weekly) in 19/54 patients who had PTH > 150 pg/mL (on peritoneal dialytic treatment for 6-114 months, weekly KT/V 2.01 +/- 0.43); 16% were in therapy with calcium (Ca) carbonate, 26% with calcium acetate alone, and 58% with calcium acetate associated with magnesium (Mg) carbonate and reduction of dialysate Ca (CaD) and dialysate Mg (MgD), respectively, to 1.25 and 0.25 mmol/L. In 5 patients (26%), a further reduction of CaD to 0 mmol/L has been necessary, and 3 patients must be considered nonresponders after three months of treatment. In conclusion, the use of calcitriol as pulse therapy (three times weekly), and at low doses, allows a good control of secondary hyperparathyroidism in 85% of patients who are using phosphate binders without aluminum, if CaD is reduced in some patients to 1.25 or even to 0 mmol/L.

Nutritional parameters in diabetic patients on CAPD.

In diabetic patients treated with dialysis, morbidity and mortality are more elevated than in nondiabetic patients. For the high dropout of diabetic patients between the first and the second year of treatment not much data are available on their nutritional parameters. For this reason, after excluding patients who had not had a two-years follow-up, we compared two groups of patients, 8 diabetics and 10 nondiabetics, similar in age (66.0 +/- 8.1 vs 65.0 +/- 8.3 years) and weight (61.8 +/- 11.9 vs 62.1 +/- 5.5 kg), measuring their nutritional parameters [body mass index (BMI), normalized protein catabolic rate (PCRN), albumin, transferrin, cholesterol], dialytic dose (Kt/V), renal residual function (RRF) and peritoneal urea (Kdu) and creatinine clearances (Kdcr) after one and 24 months of continuous ambulatory peritoneal dialysis (CAPD). At the start of CAPD, diabetics had greater weekly Kt/V (2.77 +/- 0.68 vs 2.19 +/- 0.35, p < 0.03) for a better residual renal function (5.0 +/- 2.0 vs 2.6 +/- 1.6 mL/min, p < 0.01) and greater loss of proteins in dialysate (7.8 +/- 2.3 vs 5.2 +/- 2.1 g/day, p < 0.05). After 24 months diabetic patients showed a significant decrease in albumin (3.44 +/- 0.34 vs 2.92 +/- 0.33 g/dL, p > 0.01), PCRN (1.21 +/- 0.20 vs 0.92 +/- 0.10 g/kg/day, p < 0.02), and weekly Kt/V (2.77 +/- 0.68 vs 2.25 +/- 0.38, p < 0.05), and a reduction, even if not as significant as with nondiabetic patients, in residual renal function (5.0 +/- 2.0 vs 3.0 +/- 2.3, p = NS). BMI (p < 0.01) was significantly increased in both groups, and this increase is higher in diabetic patients, while transferrin and cholesterol had no significant variations in both groups of patients. Peritoneal clearances did not change in 24 months, whereas the daily protein loss into dialysate was constantly higher in diabetic patients. In conclusion, diabetic patients have, over time, a decrease of total (renal and peritoneal) clearances of urea and creatinine (primarily because of loss of residual renal function, a reduced protein intake (evaluated as PCRN), and an increased loss of proteins from the peritoneum, which bring about a decrease in albuminemia, a possible concomitant cause of the greater morbidity and mortality in diabetic patients.

High-dose oral calcitriol and zero calcium peritoneal solutions in CAPD patients with refractory secondary hyperparathyroidism.

We evaluated the effect of pulse oral calcitriol (4 micrograms three times weekly for 6 months) on parathyroid function in nine CAPD patients with hyperparathyroidism refractory to conventional low-dose oral calcitriol. Zero calcium peritoneal solutions were used to prevent the development of hypercalcaemia. The peritoneal loss of calcium increased from 168 +/- 40 to 417 +/- 48 mg/day using zero calcium solutions. Pulse oral calcitriol resulted in a significant decrease in PTH (from 617 +/- 272 to 382 +/- 299 pg/ml) by the 15th day of therapy, while serum iCa did not change from baseline. During the first month of therapy the mean PTH levels remained significantly reduced compared to baseline, thereafter PTH increased in four of nine patients. Hyperphosphataemia was not satisfactorily controlled in four patients, despite large amounts of binders used; seven of nine patients developed hypercalcaemia and required either the substitution of calcium acetate for calcium carbonate or reduction of calcitriol dose. Three patients showed a progressive increase in PTH. In conclusion our data suggest that in most CAPD patients with severe hyperparathyroidism oral calcitriol pulse therapy is not effective in maintaining a permanent suppression in PTH levels.

Peritoneography and peritoneal computerized tomography: a new approach to non-infectious complications of CAPD.

The introduction of the contrastographic medium (PG) eventually combined with CT scan (PCT) has been used in the study of non-infectious abdominal complications of patients on CAPD. In 27 patients on CAPD from 0 to 98 months we infused, through the peritoneal catheter, 100-200 ml of iopamidol and 500-2000 ml of peritoneal dialysis solution, effecting radiograms in different projections (27 cases), with contiguous axial scannings of 10 mm (8 cases). The information obtained was useful with regard to the therapeutic choices; it clarified the extent, the width, and the anatomical relations of hernias (7/7); the leakage site at the introduction point of the catheter (2/5), and site of surgical treatment (2/5); an inguinal hernia (1/4) and the previousness of the peritoneovaginal duct (3/4) in cases of the genital oedema; a displaced non-opaque catheter (1/4); obstruction of the terminal hole (2/4); wrapping of the omentum in a catheter malfunction (1/4); the presence of scar tissue and pathological recesses in the reduction of ultrafiltration (2/3); and the extension of secondary scar tissue after surgery and before CAPD was started. There were no infective complications or allergic reactions during the research. In conclusion, after reparative surgical intervention, PG and PCT are simple, convenient investigations, with significant diagnostic usefulness, before the introduction of the catheter and/or in cases of complications during CAPD.

Plasma or whole blood concentrations of trace elements in patients treated by haemodiafiltration with on-line prepared substitution fluid.

Large membrane pores and large quantities of reinfusion fluids can influence the dialytic balance of trace elements in haemodiafiltration (HDF). As there are no studies in HDF with on-line produced reinfusate, we studied plasma or whole blood (*) concentrations of trace elements (Al, Cd*, Cr* and Se: microg/l; Cu, Pb* and Zn*: microg/dl) of 24 on-line HDF, 20 haemodialysis (HD) patients and 66 490 normal subjects (N). The concentrations of Al (11.7+/-9.5), Cd (0.73+/-0.59) and Cr (6.5+/-6.9) were significantly greater in on-line HDF patients than in normal subjects (6+/-0.4; 0.6+/-0.2; 0.5+/-0.02), but similar to those of HD patients. In on-line HDF patients, Cu (85.3+/-17.7), Pb (8+/-4.6), Se (68+/-27) and Zn (546+/-103) concentrations were less than in normal subjects (108+/-3.4; 11+/-0.8; 95+/-1.8; 673+/-23), and those of Cu and Zn were also less than in HD patients (99.5+/-16.8; 670+/-65). At the end of an on-line HDF treatment (42-69 studies), there was a significant increase in Al (from 12.8+/-9.1 to 15.4+/-8.3), Cr (from 7.2+/-6.4 to 9.5+/-7), Cu (from 97.3+/-21.5 to 109.4+/-27.2) and Zn (from 577+/-108 to 619+/-117). A longitudinal study (n = 16-18) for 12-30 months documented stable concentrations of Al, Cd, Cr, Se and Zn and a significant increase of Cu and Pb to normal concentrations. In conclusion, our on-line HDF patients have elevated Al, Cd, Cr and decreased Cu, Pb, Se, Zn concentrations in plasma or whole blood determinations. Cu and Pb normalize with time; the other trace elements remain stable as documented by numerous determinations. As the values for on-line HDF patients are similar to those of HD patients, the level of accumulation or depletion of trace elements in on-line HDF can be considered as safe as in HD; the increase in Al, Cd, Cu and Zn at the end of treatment may be an expression of the increase of those trace elements linked to proteins.

Trace elements and micropollutant anions in the dialysis and reinfusion fluid prepared on-line for haemodiafiltration.

Exposure to the trace elements and micropollutions of tap water may be very considerable in dialysis patients. As few data on trace elements in reinfusion and dialysis fluid for haemodiafiltration (HDF) have been reported, we studied nine trace elements (microg/l; Al, As, Cd, Cr, Cu, Hg, Pb, Se, Zn) and five anions (mg/l; F-, NO2-, NO3-, PO4(3-), SO4(2-)) in tap water, in water after two passages of reverse osmosis (2RO), in dialysate and in on-line prepared reinfusate. NO3- and SO4(2-) were somewhat elevated in our tap water (22.2+/-7.6 and 21.8+/-11.3 mg/l) but decreased (P<0.001) after 2RO (1.4+/-1.5 and 0.9+/-1.1 mg/l); the other anions, which were at a very low level, remained unchanged. All trace elements decreased, with statistical significance only for Al, Cr and Zn from 14.9+/-19.9, 2.6+/-0.6 and 35.1+/-41.1 microg/ to 3.2+/-2.1, 0.2+/-0.2 and 3.5+/-4.8 microg/l, respectively. Due to impurities in concentrate salts for Al (5.4+/-3.1), Cr (0.5+/-0.4) and SO4(2-) (2.4+/-1.8), greater concentrations were found in dialysate and reinfusate than in tap water after 2RO (P<0.03). For all measurements, trace elements and anions were at acceptable levels according to international standards. Simultaneous determinations of trace elements at inflow (Din) and outflow (Dout) of the dialysate as well as in plasma or in whole blood at the beginning of on-line HDF documented Dout/Din>1 for Al, Cu and Zn and a positive gradient between the concentration in blood and dialysate inlet. In conclusion, our dialysate and reinfusate can be considered safe regarding trace elements and micropollution: two passages through reverse osmosis reduces the concentrations of trace elements and anions. The impurities of concentrates are acceptable. Accumulation or depletion of trace elements should be evaluated after longitudinal studies of plasma concentrations.