Atrial fibrillation in end stage renal disease patients: influence of hemodialysis on P wave duration and atrial dimension.

BACKGROUND: Prevalence and incidence of atrial fibrillation (AF) are high in hemodialysis (HD) patients. Intra-atrial conduction velocity slowing plays an important role in AF onset. The aim of our study was to measure P wave duration (Pwd), expression of intra-atrial conduction velocity, in HD patients with and without a history of AF. METHODS: The study was performed in 47 end stage renal disease (ESRD) patients, subdivided into four groups: 19 patients within the first 6 months from starting HD therapy (HD1); the same patients studied 18 ± 3 months later (HD2); patients with no history of AF and long dialytic age (HD3, n = 13); and patients with sinus rhythm but history of AF (HDAF, n = 15); and 18 healthy controls. In all patients P wave high resolution recording and electrolyte plasma values were obtained before and after a HD session, and atrial diameter was assessed by echocardiography. RESULTS: Patients with the shortest dialysis vintage showed the shortest Pwd [131.2 ± 11.0 (HD1) vs. 139.8 ± 11.7 (HD2), 142.1 ± 7.2 (HD3), 152.3 ± 15.0 (HDAF) ms; p < 0.05], while Pwd was prolonged in patients with AF history when compared to all other groups (p < 0.03). At multivariate analysis atrial dimension was independently related to Pwd (R = 0.40, p < 0.02). HD session induced a significant increase of Pwd (141 ± 14.0-152 ± 17.0 ms, p < 0.001), that was correlated to modifications of K(+) concentration (R = 0.8, p < 0.0001). CONCLUSIONS: HD therapy prolongs Pwd. HD patients with a history of AF have prolonged Pwd compared to patients without, suggesting that increased Pwd is a marker of AF risk in patients with ESRD. HD session acutely increases Pwd, creating conditions favoring AF onset.

[The role of the nephrologist in the management of vascular access for hemodialysis]. / Dalla Mailing List Soci SIN (ML-SIN). Ruolo del nefrologo nella gestione degli accessi vascolari per emodialisi.

The role of the nephrologist in the management of vascular access for hemodialysis has recently been the subject of intense debate on the SIN mailing list. In the present issue, the topic is commented on in view of some literature data. The DOPPS Study has provided information about vascular access practice patterns in different countries. The use of arteriovenous fistula (AVF) is much more frequent in Europe than in the USA (80% vs 24%), where grafts are the most frequent vascular access (58%). In Europe, AVF is most common in Italy (90%), where nephrologists are largely in charge of vascular access surgery. AVF survival has been demonstrated to be longer than graft survival. Vascular access is also associated with patient survival, as the mortality and hospitalization risks are higher in patients with central venous catheters (CVC) and lower in those with AVF. Independent of who is in charge of vascular access surgery, nephrologists play a pivotal role as the main actors of patient care. Nephrological follow-up before dialysis initiation has been independently associated with permanent vascular access and improved patient survival. The Canadian experience, where CVC use is high due to the lag between patient referral and vascular access surgery, has taught that it is mandatory to give vascular access surgery sufficient room and time. In this respect, the nephrologist has an important role to play in the organization of vascular access surgery to fulfill patients' needs in real time.

Rectal bleeding by Dieulafoy-like lesion: successful endoscopic treatment.

A 81-year old woman affected by chronic renal failure, non insulin-dependent diabetes mellitus (NIDM) and hypertension, had an severe anemia massive hematochezia. The colonoscopy could not localize the bleeding site except some blood spots in the rectum. The patient was readmitted after 1 month with hypovolemic shock by massive hematochezia and required several blood transfusions. The endoscopic examination showed an important arterial bleeding treated successfully with epinephrine and bipolar elettro-coagulation (BICAP). We suggested that the patient presented a Dieulafoy-like lesion; this is an uncommon gastrointestinal cause of bleeding due to a defect of a submucosal artery without evidence of atherosclerosis or vasculitis. Both chronic renal failure and age could be considered as predisponent factors in this patient. Hematochezia is the most important sign and is often complicated by haemorrhagic shock. The diagnosis was delayed due to the difficulty in localizing the bleeding site; moreover, the patient needed several blood transfusions. The arteriographic diagnosis associated to endoscopic treatment by epinephrine and BICAP enabled a successful therapy.

[Alterations of cardiac output during bicarbonate hemodialysis and its relationship with other hemodynamic parameters]. / Modificazioni della gittata cardiaca durante emodialisi con bicarbonato e sue relazioni con altre variabili di pertinenza cardiologica.

PURPOSE: Time course of cardiac output (CO) and other hemodynamic parameters were measured during hemodialysis (HD). Our aims were to identify a characteristic CO profile and investigate the relationship with other hemodynamic parameters. PATIENTS AND METHODS: CO was measured with ultrasound dilution method in 45 chronic hemodynamically stable HD patients. Diabetics and patients with heart diseases were excluded. Ultrafiltration rate (UFR) was fixed at 649 +/- 244 mL/min. Pre/post statistical comparisons were performed for CO, cardiac index (IC), central blood volume (CBV) and total peripheral resistance (TPR). RESULTS: CO was pre 5.7 +/- 1.8 and post 4.5 +/- 1.4 L/min (p=0.001); IC was pre 3.2 +/- 0.9 and post 2.6 +/- 0.7 L/m2 (p=0.001); CBV was pre 1.28 +/- 0.39 and post 1.09 +/- 0.32 L (p=0.001). TPR increased from 18.7 +/- 5.6 to 22.7 +/- 6.1 mmHg/L/min (p=0.001). Maximal CO reduction rate was found at 60 min, thereafter it reduced progressively. Log(CO1) increased in a non-linear way with body weight gain and similarly it decreased during UFR. A negative correlation was found between log(TPR1) and log(CO1-QA). CO reduction was associated with UFR and not with age, dialysis duration, left ventricular hypertrophy, sex and hemoglobin (Hb) in a multiple regression model (r2 =0.31, p=0.05). Qa/CO1 was 0.16 +/- 0.12. CBV/CO increased from 0.23 +/- 0.06 to 0.25 +/- 0.07%. CONCLUSIONS: Progressive CO reduction and TPR increase appear to be the typical hemodynamic features of bicarbonate HD with a UFR of moderate degree. Volume overload and CO increase were related in a non-linear way. TPR1 was strongly correlated with CO1-Qa, suggesting that a large arterovenous shunt was associated with increased resistance.

Distal arteriovenous fistulas in elderly hemodialysis patients.

Dialysis access procedures and complications are an important cause of morbidity and hospitalization for chronic hemodialysis patients. Subjects over 65 years old have a higher incidence of co-morbid factors (diabetes mellitus, atheros clerosis, neoplasms, heart failure), therefore the correct choice in terms of timing and type of permanent access is extremely important. As elbow fistulas are often complicated by heart failure and PTFE grafts have a higher risk of thrombosis, we decided to evaluate the success rate of distal fistula as primary dialysis access in elderly patients. We carried out a retrospective study to identify survival predictors and actual vascular network saving. Between January 1991 and September 2000, 277 vascular access procedures were performed on 198 elderly patients (age 65 or older). The first anastomosis was positioned as peripherally as possible. In cases of patients with poor peripheral vasculature or three co-morbid factors, vascular access was first created at the origin of radial artery (Toledo-Pereyra fistula). Survival (Kaplan - Meyer analysis) was significantly higher for Toledo-Pereyra fistulas compared to wrist and snuff-box ones, in spite of the presence of a high incidence of co-morbid factors. We conclude that Toledo-Pereyra fistula is an efficient primary choice in elderly patients.

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.

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.

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.

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)

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.

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.