[Pre-dialysis arteriovenous fistula results in better patency rate]. / Fistola artero venosa pre-dialisi = migliori risultati.

BACKGROUND: The timing of creation of the first permanent vascular access is crucial to the clinical history of haemodialysis patients. Our strategy is to create vascular access early enough to allow its maturation before the start of the treatment. METHODS: Aim of the study is to evaluate patency of primary A-V fistulas in patients treated between 1985 and 2000 in our dialysis unit. One hundred and thirty A-V fistulas created before haemodialysis treatment (range 10-540 days) and used at its beginning (pre-HD group) are compared with 74 A-V fistulas created and/or used after the start of the haemodialysis treatment (post-HD group). RESULTS: Pre-HD group fistulas resulted in higher patency rate than the post-HD group, immediately at the start of the treatment (94.6% vs. 86.5%, p<0.05), at 6 months (89.2% vs. 75.6%, p<0.025), at 12 months (84.5% vs. 64.6%, p< 0.005), at 24 months (77.2% vs. 54.8%, p< 0.005). CONCLUSIONS: A-V fistula is to be preferred in the choice of primary vascular access for chronic haemodialysis patients. It should be created early enough before the beginning of the treatment (when serum creatinine reaches 6 to 7 mg/dL). This planning avoids central venous catheter placement, preserves vessels and the choice of the best surgical option thus resulting in a better fistula survival.

Low-dosage ibopamine treatment in progressive renal failure: a long-term multicentre trial.

A multicentre trial (11 nephrology centres) was carried out to test the effects of ibopamine, an orally active dopamine-like drug, on the progression of chronic renal failure. For a 2-year period 189 chronic renal failure patients (serum creatinine level 1.5-4.0 mg/dl) were observed. They were homogeneous for basic nephropathy, degree of residual renal function, blood pressure, and proteinuria. The patients were randomly divided into two groups: 96 took ibopamine at a dosage of 100 mg/day (group A) and 93 served as controls (group B). All were on a low-protein diet (mean 0.8 g/kg body weight). By the end of the observation period, the rate of decrease of the renal function indexes in time proved significantly slower (1.8 times) in group A than in group B. The survival curves for renal function (pre-established end points were creatinine level increases equal to or > 20% and equal to or > 40% of the basal values) proved significantly better (p < 0.02 and p < 0.002 respectively) in group A than in group B. The mean plasma creatinine values rose by 17% in group A and by 36% in group B. The creatinine clearance decreased by 5% in treated patients and by 14% in the controls. Statistical analysis ruled out any possible centre effect. The trial suggests that low-dosage ibopamine administration may be used as a valid and safe pharmacological adjunct for retarding the progression of renal failure in patients with mild or moderate chronic renal impairment.

Effects of different dialysis membranes on lipid and lipoprotein serum profiles in hemodialysis patients.

We measured the serum concentrations of a variety of lipid constituents--total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein cholesterol, apolipoproteins A1 and B, and lipoprotein(a)--in well-matched uremic patients undergoing chronic hemodialysis with either cuprophane (n = 13) or polysulfone (n = 13) membranes. We found that the patients on polysulfone membrane dialysis had significantly higher mean HDL cholesterol and apolipoprotein A1 concentrations than the patients on cuprophane membrane dialysis. There were no significant differences in the other variables studied. Moreover, polysulfone membrane dialysis was associated with a lower prevalence of potentially atherogenic lipid abnormalities such as low HDL cholesterol levels and high total cholesterol/HDL cholesterol rations. We concluded that the use of more physiological dialysis procedure may improve, in the long term, lipid and lipoprotein profiles in hemodialysis patients, though the exact mechanism(s) remains unknown.

Serum lipoprotein(a) and coronary artery disease in uremic patients on chronic hemodialysis.

There is convincing clinical and experimental evidence to support the notion that lipoprotein(a) [Lp(a)] is atherogenic. Patients undergoing chronic hemodialysis have an increased risk of atherosclerotic cardiovascular complications. In the present study, we investigated the possible relation between the alteration, if any, in serum Lp(a) and coronary artery disease in such patients. The mean serum concentration of Lp(a) tended to be higher in the 64 hemodialysis patients than in the 30 normal controls (15.1 +/- 15.2 vs. 9.7 +/- 10.4 mg/dl). However the difference did not reach statistical significance. The prevalence of levels above 30 mg/dl was 14% (9/64) and 10% (3/10), respectively, and the difference was also not statistically significant. Eleven hemodialysis patients with coronary artery disease had a significantly higher mean serum concentration of Lp(a) than the unaffected 53 (33.7 +/- 18.4 vs. 11.1 +/- 11.2 mg/dl, p < 0.001). Elevated levels were present in 63.6% (7/11) and 3.8% (2/53), respectively (p < 0.01). Other parameters of lipid metabolism were not different between the two groups. We observed statistically significant positive correlations of Lp(a) to total cholesterol, LDL cholesterol and apolipoprotein B in controls, in hemodialysis patients as a whole and in those without coronary artery disease. No such correlations were obtained when hemodialysis patients with coronary artery disease were analysed separately. It is concluded that firstly, high serum levels of Lp(a) in hemodialysis patients are strongly associated with coronary artery disease, as well as in the general population; and secondly, abnormalities in the metabolism of Lp(a) may underlie atherogenesis in these patients, independently of alterations in other lipid constituents.

Analysis of the factors influencing bicarbonate balance during acetate-free biofiltration.

In acetate-free biofiltration (AFB), the physical separation between the base losses and the gains could facilitate the modeling of intradialytic bicarbonate (HCO3) balance. In order to verify this hypothesis, we analyzed in a multicenter study, 126 AFB sessions in which differing parameters were evaluated (dialysis time, blood flow, ultrafiltration, infused HCO3, pre- and post-dialytic HCO3, hematocrit and body wt). Statistical analysis performed with multiple linear regression showed that the post-dialysis HCO3 was significantly dependent (F = 21.68, d.f. 5.95, P < 0.001) directly on the amount of infused HCO3, the level of pre-dialysis HCO3 and the final body weight, and inversely on the dialysis time and the blood flow. HCO3 values predicted by the statistical model correlated well with the observed ones (r = 0.788, P < 0.0001) with a mean absolute difference of 2.138 mEq/liter. This modeling approach allowed us to predict, with a computer-aided procedure, the quantities of HCO3 to be infused to obtain a desired and personalized acidosis correction.

Serum alpha-1-antitrypsin in hemodialysis patients with dialysis arthropathy.

Dialysis arthropathy is the most prominent dialysis-related amyloidosis feature. Alpha-1-antitrypsin (alpha-1-proteinase inhibitor) is the major circulating antiprotease. Twenty-three otherwise uncomplicated hemodialysis patients with well-documented dialysis arthropathy had a significantly (p < 0.05) lower serum mean concentration, 1,960 +/- 410.4 mg/l of alpha-1-antitrypsin than 47 patients with no joint symptoms who had a mean concentration of 2,256.6 +/- 424.5 mg/l. Decreased levels of the substance were detected in 13 (56.5%) of the 23 patients with dialysis arthropathy and in 13 (27.6%) of those 47 with no joint symptoms, the incidence in the former group being significantly (p < 0.05) higher than in the latter. In the dialysis arthropathy group, serum alpha-1-antitrypsin levels correlated inversely (r = -0.54, p < 0.01) with the dialysis duration and directly (r = 0.413, p < 0.05) with the corresponding beta-2-microglobulin determinations. We speculate that reduced antiprotease activity may play a role in amyloidogenesis in the setting of long-term hemodialysis.

Nephrotic-range proteinuria in a patient with high renin hypertension: effect of treatment with an ACE-inhibitor.

A 65-year-old man presented proteinuria in the nephrotic range that occurs in the setting of high renin hypertension. Proteinuria persisted after normalizing blood pressure by nifedipine. In contrast, treatment with an ACE-inhibitor (enalapril) resulted in the prompt resolution of the proteinuria. Interestingly, proteinuria relapsed after removing the ACE-inhibition. These observations suggest a causal relation between the overactivity of the renin-angiotensin system in this patient and his proteinuria.

Evolution of serum prealbumin following hemodialysis: effect of different dialysis membranes.

The effects of hemodialysis on the levels of serum prealbumin (pA) were studied on a crossover basis in 17 uncomplicated patients. Bicarbonate dialysate was used exclusively, and two different membranes, cuprophane and polysulfone, were compared. We aimed to prove the induction of an acute-phase response during the procedure. Serum pA, corrected for hemoconcentration, decreased significantly 24 h after the start of cuprophane hemodialysis and returned to the initial value within 48 h. No such change was observed using polysulfone membranes. These results were seemingly correlated with the effects of the membranes on complement activation. It is concluded that cuprophane hemodialysis is indeed associated with an acute-phase response, probably due to interleukin-1 release during the treatment, and that the membrane composition has some role in inducing it. Thus, serum pA analysis may prove useful as an indicator of the biocompatibility of the dialysis procedure.

Immunogenicity of a recombinant hepatitis B vaccine in hemodialysis patients: a two-year follow-up.

The immunogenicity of a recombinant hepatitis B vaccine was evaluated in 35 hemodialysis patients who received a standard dose (20 micrograms) of the vaccine at 0, 1, 2 and 6 months. After the full vaccination course (month 7), 60% (21/35) of the patients had seroconverted (anti-HBs titer greater than or equal to 10 mIU/ml). The duration of protection lasted up to 18 months after the start of vaccination in 85.7% (18/21) of the responders. At that time, an additional dose was given to all the patients: 1-2 months later, the overall immunization rate had increased to 65.7% (23/35); lastly, in month 24 (i.e., 6 months after the booster dose), 62.5% (15/24) of the patients available for evaluation were still maintaining protective levels of anti-HBs antibodies. Comparable results had previously been obtained in 21 well-matched patients on our dialysis program who were vaccinated with a plasma-derived vaccine according to the recommended schedule.

[Radiologic and clinical aspects of osteoarticular amyloidosis caused by dialysis]. / Aspetti radiologici e clinici dell'amiloidosi osteoarticolare da dialisi.

Many long-term (greater than 60 months) hemodialysis patients develop a severe osteoarticular disease, called "dialysis arthropathy", which is characterized by the deposition in bone and synovia of a new type of amyloid made mainly of beta 2-microglobulin. In the present study, 31 patients (17 males, 14 females; age 54.1 +/- 13 years), undergoing chronic hemodialysis for 60-125 months, were examined for dialysis arthropathy by means of clinics and of radiological investigations (conventional radiography and computed tomography). Sixteen patients (51.6%) had radiographic evidence of dialysis arthropathy: geodes (shoulders, 12 cases; wrists, 11; hips, 2; knees, 2) and/or destructive arthropathies (cervical spine, 13 cases, dorsolumbar spine, 2; hands, 2; hips, 1). Within 24 months, these lesions were found to progress slowly in the majority of cases. In the diagnostic process, CT should be employed in the study of spine, shoulders and hips when the lesions have not been sufficiently demonstrated by conventional radiography in the presence of evident clinical signs. Patients with dialysis arthropathy had undergone dialysis for longer periods than those without it (p less than 0.005) and showed a significantly higher incidence of both carpal tunnel syndrome (p less than 0.0005) and shoulder pain (p less than 0.005). Our findings confirm the high incidence and clinical importance of dialysis arthropathy in long-term hemodialysis patients and the value of diagnostic imaging in screening such patients for those lesions.

[Acquired cystic kidney disease among hemodialysis patients: echographic and clinical study]. / Malattia renale cistica acquisita nei pazienti in emodialisi: studio ecografico e clinico.

Thirty-six of 56 (64%) patients on chronic hemodialysis for 1 to 194 months were found to have ACKD (at least 3 cysts per kidney) by means of ultrasonographic evaluation. The number, size and extent of cysts were positively and significantly correlated with the months on hemodialysis. There was also a significant positive correlation between grade of ACKD and Hb. Moreover there was a significant positive association of abdominal pain; none had suffered from hemorrhage or neoplasm.

[Diagnostic imaging for the study of popliteal masses in dialyzed patients]. / La diagnostica per immagini nella valutazione delle masse poplitee dei pazienti in dialisi.

A new type of amyloidosis, secondary to the massive deposition of beta 2-microglobulin, has been identified which is peculiar to long-term (greater than or equal to 5 years) hemodialysis. Popliteal masses have recently been described as a possible manifestation of this type of amyloidosis. We report the results of a clinical-radiologic study of the popliteal region in 28 patients (14 males, 14 females; age 52.9 +/- 12.6 years) undergoing chronic hemodialysis for 60-212 months (mean 127 +/- 40). We aimed at determining the role of diagnostic imaging (conventional radiography, ultrasonography, Computed Tomography) in this pathologic condition. Clinics detected popliteal masses in 4 patients (bilateral in 1). US allowed 2 more cases to be detected and demonstrated the cystic nature of the lesion. Ultimately, popliteal masses could be demonstrated in 6 (bilateral in 5) of 28 patients (incidence 21.4%). In the 3 patients who were investigated by CT, cysts were seen to communicate with the joint cavity (Baker's cysts). In 1 case, immunocytochemical analysis showed diffuse beta 2-microglobulin positive amyloid deposition within the synovial wall of the surgically removed cyst. All the 6 patients experienced some of the major features of dialysis-related amyloidosis: carpal tunnel syndrome (6 cases), destructive arthropathy (5 cases), carpal and shoulder bone radiolucencies (5 and 4 cases, respectively). These findings, while documenting the high prevalence of popliteal cysts among long-term hemodialysis patients and the strong correlation with dialysis-related amyloidosis, stress the importance of diagnostic imaging in the detection and follow-up of such lesions.