Color Doppler Ultrasonography Percutaneous Transluminal Angioplasty of Vascular Access Grafts

Percutaneous transluminal angioplasty (PTA) is a possible treatment for stenosis. This study aimed to verify the impact of a vascular access (VA) surveillance protocol, based on the detection of functional changes and their correction by a new PTA method for VA performed under color Doppler ultrasonography (CDU) guidance. We divided the patients into two groups: group A, before May 1999 (retrospective study) without the surveillance protocol, and group B, from 1 May 1999 to January 2001 (prospective study) with the surveillance protocol. Access blood flow (Qa) was assessed every 4 weeks by ultrasound velocity dilution. In cases of a reduction of ≥35% from the baseline value, VA was examined using CDU: if a stenosis >50% was detected, angioplasty was performed. In cases of Qa reduction <35% we continued monitoring. By Cox's multivariate analyses, only the use of PTA with or without stenting reduced the relative risk of thrombosis by 64% during the follow-up (p=0.017 confidence intervals 88%-15%) in group B patients. Secondary patency was 80% for VA in which we performed PTA with or without stenting at 18 months, and 58% at 18 months in which we did not perform PTA. Our data show how PTA under CDU is useful to maintain and to improve graft patency. This PTA under CDU guidance allows patients to avoid surgical intervention, hospitalization, and adverse reactions to contrast media and exposure to ionizing radiation, with reduced cost and with better graft survival.

Color Doppler ultrasonography percutaneous transluminal angioplasty of vascular access grafts

Percutaneous transluminal angioplasty (PTA) is a possible treatment for stenosis. This study aimed to verify the impact of a vascular access (VA) surveillance protocol, based on the detection of functional changes and their correction by a new PTA method for VA performed under color Doppler ultrasonography (CDU) guidance. We divided the patients into two groups: group A, before May 1999 (retrospective study) without the surveillance protocol, and group B, from 1 May 1999 to January 2001 (prospective study) with the surveillance protocol. Access blood flow (Qa) was assessed every 4 weeks by ultrasound velocity dilution. In cases of a reduction of >or=35% from the baseline value, VA was examined using CDU: if a stenosis >50% was detected, angioplasty was performed. In cases of Qa reduction <35% we continued monitoring. By Coxs multivariate analyses, only the use of PTA with or without stenting reduced the relative risk of thrombosis by 64% during the follow-up (p=0.017 confidence intervals 88%-15%) in group B patients. Secondary patency was 80% for VA in which we performed PTA with or without stenting at 18 months, and 58% at 18 months in which we did not perform PTA. Our data show how PTA under CDU is useful to maintain and to improve graft patency. This PTA under CDU guidance allows patients to avoid surgical intervention, hospitalization, and adverse reactions to contrast media and exposure to ionizing radiation, with reduced cost and with better graft survival.

[Amnioinfusion: techniques, indications, and controlled retrospective study of 55 cases]

Amnioinfusion is a relatively recent procedure introduced among fetal medicine techniques. Its applications focus on two different methods: transcervical and transabdominal. The first procedure usually is carried out during "intrapartum amnioinfusion" to prevent or treat fetal heart rate (FHR) decelerations related to oligohydramnios or to dilute thick meconium staining of the amniotic fluid. The latter method used during "antepartum amnioinfusion" is usually indicated for severe oligohydramnios in order to avoid the complications related such as pulmonary hypoplasia, deforming effects of oligohydramnios, variable FHR decelerations and intraventricular hemorrhages. Antepartum amnioinfusion, also used to improve ultrasound visualisation in presence of oligohydramnios, is less employed as compared to intrapartum amnioinfusion, therefore its risks are not well established. In order to study possible adverse effects on the mother or foetus, fifty five patients affected by oligohydramnios at 17th-34th week of gestational age were submitted to antepartum amnioinfusion (1-5 procedures) and were matched retrospectively with forty seven women with the same characteristics treated with the conservative and expectant management. The trend of pregnancy was the same for both groups in relation to maternal fever > 38 degrees (10.9% in the amnioinfused group vs 17.0% in control group ns), leukocyte count > 18,000/mm3 (25.5% vs 21.3%, ns), C-reactive protein > 10 ng/ml (10.9% vs 6.4%, ns). The latency period between admission and delivery was significantly longer in the amnioinfused group than in the control one [21 (range 1-98) vs 9 days (range 0-72); p < 0.001] and the frequency of Apgar score < 7 at the 5th min was less represented in the amnioinfused group than in the control group (32.3% vs 66.6%; p < 0.001). In conclusion, it was interesting to note that antepartum amnioinfusion seems to increase the latency period between premature rupture of membranes and delivery, but it remains to clarify if this procedure is as much safe for the fetus as for the mother.

How to determine ionic dialysance for the online assessment of delivered dialysis dose

BACKGROUND

Ionic dialysance may be equivalent to blood-water urea clearance corrected for recirculation (effective urea clearance); however, this is controversial. The aims of our study were (1) to verify in vivo whether the value of ionic dialysance is affected by the method of determination, given the effect of cardiopulmonary recirculation on inlet plasma water conductivity when the inlet dialysate conductivity is changed; and (2) to define the operative modalities for determining ionic dialysance to obtain an adequate estimate of effective urea clearance.

METHODS

Thirty-three hemodialysis patients were studied during 186 dialysis sessions with low-flux polysulfone dialyzers using a modified Fresenius Medical Care 4008 B machine equipped with meters to measure inlet and outlet dialysate conductivities. This machine varied inlet dialysate conductivity (Cdi) according to the following pattern: starting from baseline (step 0), Cdi was increased by 8% (step 1). After Cdi had reached the target value, which took 8 to 10 minutes, it was lowered to 8% below the baseline value (step 2). After 8 to 10 minutes, when Cdi had reached the new target, it was returned to its starting value (step 3). Four values of conventional ionic dialysance (using the standard formula) and actual ionic dialysance (taking into account cardiopulmonary recirculation) were obtained for each cycle and were compared among them and with effective urea clearance (Kde).

RESULTS

Mean conventional dialysance values at steps 0 to 2 and 2 to 3 (190 and 189 mL/min) were similar and higher than those at steps 0 to 1 and 1 to 2 (171 and 181 mL/min). Mean conventional ionic dialysance values underestimated Kde, particularly at steps 0 to 1 (-22.2 mL/min, P < 0.001) and 1 to 2 (-12.6 mL/min, P < 0.001). The actual dialysance values underestimated Kde by no more than 4.3 mL/min (P < 0.001). In steps 0 to 1 and 1 to 2, the underestimate of Kde by conventional dialysance increased at higher values of Kde, but this relationship did not exist when considering actual dialysance.

CONCLUSIONS

The value of ionic dialysance is affected by the method of determination, given the effect of cardiopulmonary recirculation on inlet plasma water conductivity when inlet dialysate conductivity is changed. As a consequence, to provide a correct and direct estimate of effective urea clearance, ionic dialysance must be determined by changing inlet dialysate conductivity in such a way as to keep inlet plasma water conductivity constant by means of two symmetrical high and low dialysate conductivity steps.

Survival of prosthetic grafts of different materials after impairment of a native arteriovenous fistula in hemodialysis patients

In our department, hemodialysis vascular accesses with graft, are used in patients with impairment of native distal and proximal arteriovenous fistulas (AVF-E). The aim of this study was to compare the survival of grafts of different materials (PTFE vs. bovine vein) in these patients. From 1991 to 1999, we prospectively evaluated 53 patients (35 women, 18 men, age 68 +/- 11 years, on dialysis for 70 +/- 65 months). Fifty-three PTFE, 10 reinforced PTFE, and 22 bovine vein grafts were placed. We evaluated the primary patency (PP) (days between fistula placement and the last dialysis before thrombosis occurred) and the secondary patency (SP) (days between fistula placement and the last dialysis treatment before it was considered lost) by separating PTFE survival from that of bovine veins. In the same patients, we also evaluated the survival of the native arteriovenous fistulas (AVF-E) during the pregraft period. Furthermore, we evaluated 404 patients (172 women, 232 men, age 65 +/- 14 years, on dialysis for 50 +/- 53 months) in whom only AVF-E were placed during the same follow-up period. Graft and AVF-E survival were calculated according to the Kaplan-Meier method. In patients with grafts, the PP at 1 year was 17.4% for PTFE and 23.9% for bovine veins. At 12 months, the SP of bovine veins was significantly higher than that of PTFE (81,9% vs. 50%, p < 0.04). In the patients who only had AVF-E, the PP and SP was, respectively, 43% at 12 months and 52.4% at 50 months. A preliminary experience in 22 patients with a 20 month follow-up confirms better survival of bovine veins than PTFE (p < 0.04).

Spurious estimations of sodium removal during CAPD when [Na](+) is measured by Na electrode methodology

BACKGROUND

The aim of this study was to investigate the effect of pH and glucose concentration on sodium removal and the dialysate and plasma sodium ratio (D/PNa) as measured by means of a flame photometer (NaF) or direct ion-selective electrode (NaE) in continuous ambulatory peritoneal dialysis (CAPD).

METHODS

In vitro, glucose concentration, pH, NaF, and NaE were measured in fresh peritoneal dialysis solutions (PDSs) before and after the addition of glucose or KOH. In vivo, 66 four-hour peritoneal equilibration tests were performed in 35 patients on CAPD using a low pH PDS with a glucose concentration of 3.86%.

RESULTS

In vitro, NaF and NaE were significantly influenced by the glucose concentration and pH of the PDS. In vivo, in fresh PDS, there was a significant difference between the NaF and NaE results; the respective median values were 132.1 (interquartile range 129.3 to 137.5) versus 138.0 (134.4 to 141.5) mmol/L (P < 0.0001). The D/PNa ratio calculated by NaE was significantly lower than that calculated by NaF (0.88 +/- 0.03 vs. 0.91 +/- 0.04 and 0. 90 +/- 0.03 vs. 0.94 +/- 0.04 at 60 and 240 min, respectively, P < 0.0001), whereas there was no significant difference between the NaE and NaF values after correction for plasma water and a Donnan factor of 0.96 (0.88 +/- 0.03 vs. 0.88 +/- 0.04 and 0.90 +/- 0.03 vs. 0.91 +/- 0.04, P < 0.3473). Sodium removal was significantly lower when calculated as NaE than when calculated as NaF (43.9 +/- 32.7 vs. 61.0 +/- 32.2 mmol, P < 0.0001).

CONCLUSIONS

The fresh PDS sodium concentration can be corrected using a glucose concentration-related factor. The D/PNa ratio calculated as NaE or NaF is not different after correction for plasma water and a Donnan factor of 0.96. Sodium removal must be measured by means of NaF rather than NaE. This could have an important clinical impact.

Color doppler ultrasonography imaging to guide transluminal angioplasty of venous stenosis

BACKGROUND

The objective of access surveillance is the early recognition of dysfunction in order to be able to correct the stenosis by angioplasty or surgery before access thrombosis occurs. The advent of color Doppler imaging has enabled studies of color Doppler ultrasonography (CDU) for the guidance of percutaneous transluminal angioplasty (PTA). The aim of the present study was to investigate whether color Doppler imaging alone can be safely and effectively used to diagnose vascular graft access stenoses and guide subsequent PTA.

METHODS

Using the ultrasound velocity dilution method, we measured access blood flow (Qa) during the first hour of hemodialysis every month in patients with grafts as vascular access. When the decrease in Qa from the baseline value was 40% or more, CDU was performed and immediately followed by PTA in the presence of a stenosis of more than 50%. The Qa was then measured during the first dialysis after PTA and one month later. Repeated-measure analysis of variance was applied to evaluate the early and late (after one month) effect of PTA.

RESULTS

Twelve PTAs were performed under CDU guidance in nine patients and led to the elimination of the stenosis or its reduction (two cases). The mean Qa was 809 +/- 263 mL/min at baseline, 468 +/- 153 before PTA, and 820 +/- 281 after PTA. The difference between the pre-PTA and post-PTA values was highly significant (P < 0.001), and the mean value after PTA was not different from baseline (P = 0.672). There were no relevant complications directly related to the procedure.

CONCLUSIONS

The CDU procedure is effective for the diagnosis of vascular access stenosis and as a guide during the PTA procedure. It could improve stenosis screening by avoiding the risks of exposure to ionizing radiation and of adverse reactions to contrast media.

'Pulse oral' versus intravenous calcitriol therapy in chronic hemodialysis patients. A prospective and randomized study

The aim of this prospective and randomized study was to compare the efficacy, side effects, and costs of 'pulse oral' versus intravenous calcitriol in the treatment of secondary hyperparathyroidism in hemodialysis (HD) patients. A total of 20 patients were randomized to receive over a 4-month period pulse orally administered calcitriol (pulse oral group; n = 10) or intravenous calcitriol (intravenous group; n = 10). All patients used standard dialysate calcium (1.75 mmol/l) throughout the study period. In accordance with the study design calcium dialysate concentrations were reduced when this was necessary to avoid hypercalcemic crises. The patients were stratified into two subgroups according to their initial serum PTH levels: patients with mild or moderate degree of hyperparathyroidism (17 patients) and patients with severe hyperparathyroidism (3 patients). Intravenous and pulse oral cacitriol did not significantly reduce serum PTH concentrations in patients with severe hyperparathyroidism (1,157 +/- 156 vs. 807 +/- 228 pg/ml [corrected], p = 0.09). Intermittent calcitriol, administered by intravenous or oral route, significantly reduced serum PTH levels (326 +/- 119 vs. 109 +/- 79 pg/ml [corrected], p = 0.0001) in patients with mild or moderate hyperparathyroidism. In patients with mild or moderate hyperparathyroidism, intravenous calcitriol significantly reduced PTH concentrations at the end of the 1st month, before the increase of serum ionized calcium levels, whereas 'pulse oral' calcitriol significantly suppressed parathyroid activity at the end of the 2nd month. Calcium dialysate concentration was reduced in 9 out of 10 (90%) patients of the pulse oral group and in all patients (10/10) of intravenous group. The incidence of hypercalcemic crises was 24% (39/160) in the pulse oral group and 14% (27/160) in the intravenous group. Analysis of costs showed that intravenous calcitriol was more expensive compared to pulse oral calcitriol. These data indicate that intermittent intensive calcitriol therapy, regardless of the route of administration, is effective in suppressing parathyroid activity in HD patients with mild or moderate hyperparathyroidism. In contrast, intermittent calcitriol therapy has a limited ability to achieve sustained serum PTH reductions in HD patients with severe hyperparathyroidism. Intravenous calcitriol was more expensive than pulse oral calcitriol, and we recommend the use of pulse oral calcitriol in HD patients with mild or moderate secondary hyperparathyroidism.

Hepatitis G virus infection in chronic dialysis patients and kidney transplant recipients

BACKGROUND

The cloning of the hepatitis G virus (HGV), a novel RNA virus of the Flaviviridae family, has been very recently developed. HGV is known to be parenterally transmitted and has been detected in several patients with cryptogenic hepatitis. However, little information exists about the epidemiology of HGV infection in renal patients. We studied 178 chronic dialysis patients and 11 renal transplant individuals to evaluate prevalence, risk factors, and clinical manifestations of HGV infection in this population.

METHODS

Hepatitis G virus infection has been detected by a modified PCR technology which incorporates digoxigenin-labelled nucleotides into the amplicon. Primers from the non-coding region and the NS-5 region of HGV are utilized for a single round amplification. Using a streptavidin surface and a biotin-labelled capture probe, the labelled nucleic acid is bound through the capture probe to the surface, and the amplified nucleic acid is detected using antibody to digoxigenin.

RESULTS

HGV RNA was detected in 6% of chronic haemodialysis (HD) patients (11/172), 36% of renal transplant recipients (4/11), and 17% (1/6) of patients on peritoneal dialysis treatment (CAPD). There were no significant differences between HGV positive and negative patients on chronic HD treatment with regard to several demographic, biochemical and virological features. However, the frequency of anti-HCV antibody was significantly higher in HGV-positive than HGV-negative patients (9/11 (82%) vs 51/161 (32%), P = 0.006). In the whole group of HGV RNA-positive patients, 78% (11/14) had a history of blood transfusion requirements, 14/16 (87%) had co-infection with HCV, and 1 (6%) had co-infection with HBsAg. There was no significant association between HCV genotypes and HGV RNA positivity. Six (37.5%) of 16 HGV RNA-positive patients showed raised aminotransferase values in serum.

CONCLUSIONS

Patients on maintenance dialysis and kidney transplant recipients are at increased risk of HGV infection; HGV is very frequently associated to hepatitis C co-infection, regardless of HCV genotype. HGV may be transmitted by blood transfusions but transmission routes other than transfusion are possible; 37.5% of HGV RNA-positive patients showed raised serum aminotransferase levels. Further investigations are necessary to clarify the role of HGV infection in the development of liver disease in this clinical setting.

Intradermal versus intramuscular hepatitis b re-vaccination in non-responsive chronic dialysis patients: a prospective randomized study with cost-effectiveness evaluation

BACKGROUND

It has been calculated that 30% of chronic uraemic patients fail to produce antibodies to HBsAg antigen after hepatitis B (HB) vaccination. Low-dose intradermal (i.d.) inoculations and supplementary intramuscular (i.m.) injections have been reported to improve the response rate in previous non-responder chronic uraemic patients, but no cost-effectiveness evaluations have been made about this issue.

METHODS

We re-vaccinated 50 chronic dialysis patients, who did not have any detectable anti-HBs antibody after a reinforced protocol of hepatitis B vaccine given by i.m. route, with hepatitis B recombinant DNA yeast vaccine (80 micrograms) by intradermal (25 patients) or intramuscular (25 patients) administration (randomly allocated). We used the same amount of HBsAg in order to exclude the confounding effect of the dose level administered on the immune response of uraemic patients. We studied, over a 20-month follow-up, the persistence of anti-HBs antibodies in our responder vaccinees. We made a comparison between the costs of our re-vaccination protocol and the other re-vaccination strategies that have been recently suggested.

RESULTS

One month after completion of re-vaccination protocol, seroconversion rates (100% vs 48%, P = 0.008) and proportion of patients who elicited protective anti-HBs titres (96% vs 40%, P = 0.0001) were significantly higher in i.d. compared to i.m. patients. The levels of anti-HBs expressed as geometric mean titres and 95% confidence intervals (GMT (95% CI)), were significantly increased in i.d. than in i.m. groups, 100 (44-187) vs 26 (14-52) mUI/ml (P = 0.018). At month 12, the seroconversion rates were 57 vs 14% in i.d. and i.m. groups respectively (P = 0.158); the seroprotection rate was higher in i.d. individuals in comparison with i.m. patients, 50 vs 0%, P = 0.072. At month 20, the seroconversion rates were 54 and 0% among i.d. and i.m. patients respectively (P = 0.055); the seroprotection rate was higher in i.d. than in i.m. group (30 vs 0%, P = 0.2). At month 20, the median anti-HBs titres in i.d. patients were 21 mUI/ml, and GMT (95% CI) were 20.9 (2-54) mUI/ml. No important general or local side-effects were observed. The cost of our schedule was $92 US whereas the costs of other re-vaccination protocols ranged between 138 and $807 US.

CONCLUSIONS

Our results show that the unresponsiveness to recombinant yeast-derived vaccine may be mostly reversed by repeated low-dose i.d. injections of the same agent. In spite of an equal amount of HBsAg received, i.d. hepatitis B re-vaccination shows higher immunogenicity compared to i.m. administration over a 20-month observation period. Cost-effectiveness analysis demonstrated that the intradermal administration of HB vaccine is the most clinically effective re-vaccination strategy; it is also the most unexpensive one. We strongly recommend low-dose intradermal inoculations in order to re-vaccinate chronic dialysis patients who fail to respond to hepatitis B vaccination.

Serologic survey for control of hepatitis C in haemodialysis patients: third-generation assays and analysis of costs

There is little information about the serologic survey for control of hepatitis C by using third-generation assays among chronic haemodialysis (HD) patients, and no analysis of costs has been made to this end. A serologic survey for control of hepatitis C was performed in 190 HD patients attending a single dialysis unit, using second- and third-generation assays. Costs of both serologic surveys were calculated. Anti-HCV prevalence tested by third-generation assays increased from 25% (48/190) to 28% (53/190) compared to second-generation testing; 56% (9/16) of patients showing uncertain findings by second-generation tests gave unequivocal results by third-generation assays; median duration of HD treatment and raised aminotransferase levels were positively associated (P = 0.004 and P = 0.012, respectively) with anti-HCV detected by third-generation assays. The serologic survey for control of hepatitis C in HD patients at our centre was slightly more expensive by third-generation assays compared to second-generation testing (US$18866 vs US$17200 per year). In summary, the use of third-generation tests largely clarified the uncertain results of second-generation tests; new additional positive patients were detected by third-generation assays compared to second-generation testing. Third-generation assays showed the association of duration of HD treatment and raised aminotransferase levels with anti-HCV antibody, as previously found by first- and second-generation assays. To date, third-generation screening and confirmatory assays seem extremely useful in the serologic survey for control of hepatitis C in HD centres without a considerable outlay.

Hepatitis E virus infection in haemodialysis patients: a seroepidemiological survey

BACKGROUND

Hepatitis E virus (HEV) is the causative agent for enteric non-A, non-B hepatitis. Transmission is via the faecal route but the possibility of transmission by blood has been raised. Data concerning anti-HEV prevalence among chronic haemodialysis (HD) patients are few and give conflicting results.

METHODS

We tested for anti-HEV antibody 204 chronic HD patients attending a single dialysis unit. A specific solid-phase enzyme-linked immunoassay (Abbott HEV EIA) was used.

RESULTS

We found six anti-HEV-positive patients, the anti-HEV prevalence was 3% (95% CI 0-6%). The prevalence rates of HBV and HCV infections were 39% (31-45%) and 22% (16-28%) respectively. No anti-HEV-positive patient showed past or current biochemical signs of liver damage. One of six (17%) anti-HEV-positive patients was an immigrant; no risk factor for anti-HEV antibody was identified in the other anti-HEV-positive individuals.

CONCLUSIONS

We observed a low anti-HEV prevalence: there was no association between HEV and blood-borne infections (HBV, HCV, and HIV) in our HD patients; most anti-HEV-positive patients we found were probably related to a local infection by HEV. This is one of the first reports concerning seroepidemiology of HEV infection in a large cohort of chronic HD individuals.

Intradialytic calcium balances with different calcium dialysate levels. Effects on cardiovascular stability and parathyroid function

It has been shown that calcium carbonate (CaCO3) is an effective phosphate binder which is less toxic than Al(OH)3. However, given that its use with standard calcium dialysate (CaD) levels may lead to hypercalcemia, a decrease in CaD levels has been proposed. The aim of the present study was to elevate the acute clinical and biochemical consequences of a lowering of CaD in HD patients. Dialysate composition was otherwise the same. (1) Blood pressure levels (BP) during short hemodialysis were measured in a group of 12 patients who underwent alternate hemodialyses with dialysate calcium of 1.75 and 1.25 mmol/l. (2) Ca2+ and PTH kinetics during short hemodialysis were studied in a group of 6 patients who were sequentially treated with 1.75 and 1.25 mmol/l CaD. The results show: (1) that cardiovascular stability in chronic HD patients during short HD sessions with low CaD (LCaD) may be good; (2) that a single treatment with standard CaD (SCaD) produces positive calcium balances (JCa2+) with Ca2+ plasma increase and PTHi inhibition at the end of HD sessions; during HD with LCaD there were neutral mean JCa2+ and no changes in post-dialysis mean Ca2+ and PTHi plasma levels; furthermore 2 patients showed a small PTHi increase during HD with LCaD and neutral JCa2+ because of a high positive bicarbonate balance during HD. In conclusion, as with several aspects of dialysis treatment, dialysate calcium levels should also be individualized to avoid hypercalcemic crises or PTHi stimulation.

Comparison of second-generation screening and confirmatory assays with recombinant antigens and synthetic peptides against antibodies to hepatitis C virus: a study in renal patients

The aim of this study was to compare some common tests which are nowadays routinely used to screen and to confirm anti-HCV antibodies in renal patients. There was agreement between Ortho 2 and Abbott 2 in 94% of samples; structural and nonstructural beads of the Abbott supplementary assay were in agreement with 4-RIBA in 98 and in 85% of samples, respectively; 61% of Ortho 2 samples and 65% of Abbott 2 samples were confirmed by 4-RIBA; there was a correlation between semiquantitative analysis of screening tests (Ortho 2 and Abbott 2) and positive results by 4-RIBA; 36 and 33% of Ortho-2- and Abbott-2-positive samples were 4-RIBA indeterminate: in these instances more sophisticated techniques (polymerase chain reaction) (PCR) could be useful as a third-level assay. The comparison between Ortho 2, based on recombinant antigens, and Innotest, based on synthetic peptides, showed agreement only in 44% of samples, but this preliminary comparison cannot afford definitive conclusions. These findings suggest that second-generation assays may sometimes yield conflicting results in renal patients. These contradictions will be resolved by new HCV tests or PCR.

Antibodies to hepatitis C virus (HCV) in chronic renal failure (CRF) patients on conservative therapy: prevalence, risk factors and relationship to liver disease

There are no data regarding HCV prevalence in CRF patients not requiring dialysis. In order to assess prevalence and risk factors for HCV infection in CRF patients on conservative therapy we tested, by second-generation assays such as Ortho 2 and 4-RIBA, 221 predialysis CRF patients attending our Department. Forty-four (20%) patients were anti-HCV positive. Anti-HCV positivity was related to blood transfusion requirement, past or current elevations of transaminase levels and, to a lesser degree, CRF duration. The prevalence of anti-HCV positivity among CRF patients who were never transfused was about 10 times higher than that of blood donors. Our data show that predialysis CRF patients should be considered a specific risk group for HCV infection; blood transfusion history and duration of CRF are risk factors for acquisition of HCV infection; HCV infection may play a role in the development of liver disease in this clinical setting.

Antibodies to hepatitis C virus (HCV) and transaminase concentration in chronic haemodialysis patients: a study with second-generation assays

We used first- and second-generation assays such as Ortho 1, Ortho 2 and 4-RIBA to define prevalence and risk factors for anti-HCV antibodies in haemodialysed patients. Forty-nine (24%) subjects were found to be anti-HCV positive. Anti-HCV positivity was related to duration of dialysis and past or current elevations of GOT and GPT; the frequency of transfused patients was greater in HCV-positive than in HCV-negative subjects; there were 31 patients (prevalence of 20%) with anti-HCV antibodies among non-transfused patients. These findings show that, tested by second-generation assays, HCV infection is detected more than twice as commonly in haemodialysis patients and may be responsible for a significant proportion of liver disease in this clinical setting. Acquisition of hepatitis C virus by dialysis patients is not only through blood transfusions but also secondary to hepatitis C virus presence within the unit itself.