Prevention of secondary hyperparathyroidism in hemodialysis patients: the key role of native vitamin D supplementation.

Secondary hyperparathyroidism (SHPT) is a frequent complication in chronic kidney disease, especially in hemodialysis (HD) patients. Treatments for SHPT include calcitriol analogues (CA), phosphate binders, cinacalcet (CC), and surgical parathyroidectomy (PTX). This study aimed to assess the incidence and prevalence of SHPT in a single center during the period when native vitamin D (N-VitD) supplementation and CC treatment became available. All incident and prevalent HD patients were prospectively recorded and compared using 3 periods from 2004 to 2005 (period 1), 2006 to 2007 (period 2), and 2008 to 2009 (period 3). SHPT was diagnosed with serum parathyroid hormone (PTH) levels >300 pg/mL or the need for CA, CC, or PTX. Between periods 1 and 3, in incident patients (n=120 and 101), N-VitD prescription increased from 11% to 68% (P<0.0001), CA prescription remained stable (40%), and patients with PTH>300 pg/mL decreased from 40% to 12% (P<0.0001). In prevalent HD patients (n=235), N-VitD treatment increased from 55% to 91% (P<0.0001), whereas treatment with CA decreased from 67% to 17% (P<0.0001). Patients with serum PTH>300 pg/mL decreased from 38% to 13% (P<0.001), whereas patients with PTH<150 pg/mL remained stable (<30%). New CC prescriptions decreased from 45 to 3 (P<0.0001). Since 2004, SHPT has decreased drastically in incident and prevalent HD patients. The preventive role of N-VitD supplementation appears to be obvious and represents one more argument for its general recommendation in CKD patients.

Evidence for persistent vitamin D 1-alpha-hydroxylation in hemodialysis patients: evolution of serum 1,25-dihydroxycholecalciferol after 6 months of 25-hydroxycholecalciferol treatment.

BACKGROUND: End-stage renal disease (ESRD) patients are thought to have impaired 1-alpha-hydroxylase capacity, but an extrarenal source of 1,25(OH)(2)D has been recognized. OBJECTIVE: The aim of this study was to assess the evolution of serum 1,25(OH)(2)D in hemodialysis (HD) patients with vitamin D deficiency after 6 months of 25(OH)D(3) supplementation, and to identify the factors associated with persistent 1,25(OH)(2)D production. METHODS: HD patients in a HD center with vitamin D deficiency (i.e. 25(OH)D <75 nmol/l) who were not receiving any vitamin D derivatives or calcimimetics were studied. Patients who had previously undergone parathyroidectomy or nephrectomy or those with uncontrolled hypercalcemia or hyperphosphatemia were excluded from this study. The patients were administrated a dose of 10-30 microg/day of oral 25(OH)D(3) based on the severity of their deficiency. The serum levels of 25(OH)D and 1,25(OH)(2)D evolution after 6 months were recorded. Responders were defined as patients with an increase in serum 1,25(OH)(2)D levels greater than the median value. Changes in mineral metabolism parameters were compared with those in the nonresponders. RESULTS: Of the 253 patients, 225 (89%) were vitamin D-deficient, and 43 met the inclusion criteria. The patients were 72.6 +/- 10 years old and had been on dialysis for 71 +/- 70 months; 39% of the patients were female and 45% were diabetics. From baseline to 6 months of treatment, serum 25(OH)D levels increased from 27.8 +/- 18 to 118 +/- 34 nmol/l (p < 0.001) and serum 1,25(OH)(2)D levels increased from 7.7 +/- 5 to 30.5 +/- 15 pmol/l (p < 0.001) with a median increase of 20 pmol/l. The mean serum calcium level increased from 2.19 +/- 0.1 to 2.25 +/- 0.1 mmol/l (p = 0.009), the intact parathyroid hormone (iPTH) level decreased from 144 +/- 108 to 108 +/- 63 pg/ml (p = 0.05), and the bone alkaline phosphatase (BALP) level remained unchanged. The serum phosphate level increased slightly from 1.22 +/- 0.3 to 1.34 +/- 0.2 mmol/l (p = 0.04) with reduced hypophosphatemia. Compared with the responders (n = 24), most of the nonresponders (n = 19) were diabetic (63 vs. 29%, p = 0.02) and had a lesser increase of their 25(OH)D serum level. The serum level of FGF-23 was not significant. A positive correlation was observed between serum 1,25(OH)(2)D and serum 25(OH)D levels after 6 months of 25(OH)D(3) treatment (p = 0.02). CONCLUSION: The Kidney Disease Outcomes Quality Improvement (KDOQI) guidelines do not recommend checking and treating vitamin D deficiency in chronic kidney disease (CKD) stage 5 patients due to the supposed lack of 1,25(OH)(2)D production. These data confirm persistent renal or extra-renal production of 1,25(OH)(2)D in HD patients after 6 months of 25(OH)D(3) administration. Diabetes is the main factor associated with impaired 1,25(OH)(2)D production. 25(OH)D(3 )administration corrects vitamin D deficiency with few effects on mineral metabolism and stability of bone turnover markers.

Role of sodium in dialysis.

The total amount of sodium present in the body conditions the extracellular compartment volume. In advanced renal failure and in dialysis the sodium balance becomes positive and the extracellular volume inflates. This leads to hypertension and to direct cardiac and vascular changes that explain for a large part the excessive cardiovascular morbidity and mortality in dialysis patients. Controlling body sodium content and extracellular volume allows to reduce hypertension, cardiovascular changes and to improve dialysis patients survival. This can be achieved by reducing the sodium input (low sodium diet and reasonably low sodium dialysate) and/or by increasing sodium output (ultrafiltration by convection in hemodialysis or hemofiltration and osmotic drive in peritoneal dialysis). The intermittent nature of hemodialysis (and hemofiltration) conditions the saw-tooth volume fluctuations that drove to conceiving and implementing the concept of a dry weight, corresponding to normal extracellular volume and blood pressure.

Risk factor analysis for long-term tunneled dialysis catheter-related bacteremias.

Infection, mainly related to vascular access, is one of the main causes of morbidity and a preventable cause of death in hemodialysis patients. From January 1994 to April 1998 we conducted a prospective study to assess the incidence and risk factors of catheter-related bacteremia. One hundred and twenty-nine tunneled dual-lumen hemodialysis catheters were inserted percutaneously into the internal jugular vein in 89 patients. Bacteremia (n = 56) occurred at least once with 37 (29%) of the catheters (an incidence of 1.1/1,000 catheter-days); local infection (n = 45, 1/1,000 catheter-days) was associated with bacteremia in 18 cases. Death in 1 case was directly related to Staphylococcus aureus (SA) septic shock, and septicemia contributed to deaths in 2 additional cases. Catheters were removed in 48% of the bacteremic episodes. Treatment comprised intravenous double antimicrobial therapy for 15-20 days. Bacteriological data of bacteremia showed 55% involvement of SA. Nasal carriage of SA was observed in 35% of the patients with catheters. Bacteremic catheters were more frequently observed in patients with diabetes mellitus (p = 0.03), peripheral atherosclerosis (p = 0.001), a previous history of bacteremia (p = 0.05), nasal carriage of SA (p = 0.0001), longer catheter survival time (p = 0.001), higher total intravenous iron dose (p = 0.001), more frequent urokinase catheter infusion (p < 0.01), and local infection (p < 0.001) compared with non-bacteremic catheters. Monovariate survival analysis showed that significant initial risk factors for bacteremia were nasal carriage of SA (p = 0.00001), previous bacteremia (p = 0.0001), peripheral atherosclerosis (p = 0.005), and diabetes (p = 0.04). This study confirms the relatively high incidence of bacteremia with tunneled double-lumen silicone catheters and its potential complications. Possible preventive actions are discussed according to the risk factors.

Long-term outcome of permanent hemodialysis catheters: a controlled study.

AIMS: Hemodialysis tunneled catheters are widely used nowadays. However, their complications, infection and dysfunction, remain much too frequent. Different types of tunneled silicone hemodialysis catheters are available. We prospectively compared the long-term outcome of the two most popular devices, Permcath cuffed double catheter and TwinCath uncuffed twin catheter, both inserted percutaneously. METHODS: From January 1994 to April 1998, 125 tunneled catheters were inserted in the internal jugular vein of 86 chronic hemodialysis patients, 63 TwinCath MedComp (TC) and 62 Permcath Quinton (PC). They were prospectively followed looking for technical patency, infection and dysfunction rate. RESULTS: TC were used more often for iterative access (52 vs. 25%, p = 0.01) and were inserted more frequently in the left internal jugular vein (59 vs. 16% p < 0.001). Their median technical survival rate was longer (869 vs. 433 days for PC, p < 0.01) with a 1-year patency rate of 80 vs. 53% (p = 0.002). Total catheter extrusion was also slightly less frequent with TC (4.7 vs. 9.6%), but partial extrusion happened more frequently (43 vs. 16%, p = 0.02). No significant difference in infection rate was observed, 0.77 for TC vs. 1.3 local infection/1,000 catheter days; 1.08 vs. 1.30 bacteremia/1,000 catheter days. A persistent catheter thrombosis was observed in 7.9 vs. 20.9% in PC (p = 0.04), the number of dysfunction was 10.5 vs. 24/1,000 days in use (p = 0.0001) and the number of urokinase infusion was 4.4 vs. 12/1,000 days (p = 0.001). PC needed more radiological interventions for dysfunction with endolumenal brushes (4 vs. 0) or fibrin sleeve removal (4 vs. 0). The vena cava thrombosis incidence was not different (2 vs. 3). CONCLUSION: Although the study was not randomized, TC appears more efficient allowing for a longer patency with a lower dysfunction rate than PC. This was reinforced by less favorable conditions of TC including more left jugular side and more iterative catheters. The cuff does not offer a better bacteriological barrier or protection against extrusion, and the TC seems at a less risk of fibrin sleeves. However, a large randomized study is needed to definitively conclude.

Diabetes mellitus in Tassin, France: remarkable transformation in incidence and outcome of ESRD in diabetes.

The incidence and prevalence of diabetes mellitus (DM) in the dialysis population in Europe, and more especially in France, have been lagging behind the impressive United States and Japanese rates. For a decade, things have been changing, and the incidence of DM in hemodialysis (HD) reached almost 40 in Tassin, France in 1999. The prevalence has followed the same trend but increased more slowly. The increase in incidence and prevalence is almost totally accounted for by type 2 DM explosive outbreak and development. The morbidity on dialysis (hypotensive episodes, hospitalization number, and duration) was significantly worse in diabetic patients (without difference between type 1 and 2) than in nondiabetic patients. The mortality rate was higher in diabetic patients than in nondiabetic patients (mean half-life 3 and 13 years, respectively), even after adjustment for age and comorbidity. The mortality rate was higher in type 2 than in type 1 (mean half-life 2.7 and 5.2 years, respectively), a difference which disappears when adjusting for age and comorbidity. Specific causes of death were different in diabetic and nondiabetic HD patients; in diabetics there was a six-fold higher cardiovascular (CV) and three-fold higher infectious mortality, but there was the same mortality from cancer. A strong difference was observed between type 1 and type 2 DM: in type 1 there was no increased infectious mortality and a moderately increased CV mortality compared with nondiabetic patients. Type 2 diabetic patients had a four-fold increased infectious and an eight-fold increased CV mortality. Altogether, the eruption of DM in our unit over the last decade has drastically increased the crude mortality, but the standardized mortality ratio using the USRDS mortality table remained unchanged, about 45 of expected mortality.

Malnutrition in long-term haemodialysis survivors.

BACKGROUND: Long survival is now common in patients with end-stage renal disease owing to improvement in dialysis techniques and kidney transplantation. As malnutrition is commonly reported in dialysis patients, we evaluated the nutritional status of patients treated with haemodialysis (HD) for more than 20 years. METHODS: Ten patients (59.5 years old; 4F/6M; HD treatment for 304 months; group A) underwent an extensive nutritional examination and were compared to a control group of 10 patients treated with HD for an average of 51 months and strictly matched for age (58.6 years old), gender, and height (group B). The patients were treated on a similar basis (long-duration HD, cellulosic membranes, Daugirdas index >2). RESULTS: The body weight (BW) in group A had decreased gradually from the 11th year of HD treatment, whereas it had increased by an average of 1.9+/-4.4% since the beginning of the HD treatment in group B. The body mass index (BMI) was lower in group A (19.3 +/- 2.3 vs 21.4 +/- 2.8 kg/m(2); P = 0.05). The arm-muscle circumference (AMC), the arm-muscle area (AMA), and triceps skinfold (TSF) were lower in group A than in group B. The fat mass assessed with anthropometry (10.8 +/- 4.0 vs 14.8 +/- 4.2 kg) was significantly lower in group A. The deviation of actual BW from ideal BW (IBW) was significantly lower in group A than in group B (80.6 +/- 10.7% vs 89.6 +/- 9.0%; P = 0.028); The deviations of actual BW, TSF, and AMA from standard values of the NHANES II study were more marked in group A than in group B. On the other hand, daily energy and protein intakes (DEI and DPI) were identical in both groups and met the recommendations for dialysis patients when normalized to the actual BW. When normalized to the IBW, the DEI appeared low. Energy expenditure was not different between groups, and not different from the resting metabolism calculated from the Harris and Benedict formula. Average albumin, prealbumin, and IgF-1 were normal and not different between groups. Branched-chain amino acids (BCAA), and especially leucine, were correlated with BMI in group A but not in group B. Serum total and free carnitine were low in both groups. Three patients had ascorbic acid deficiency in group A but none in group B. CONCLUSIONS: Hence, despite adequate dialysis dose and protein intake, patients treated with HD for a long period of time became malnourished, whereas the classical nutritional markers remained in normal ranges. Among the potential causes leading to malnutrition, inadequate energy intake and micronutrient deficiencies were found in these patients.

[Prevalence of stenosis and thrombosis of central veins in hemodialysis after a tunneled jugular catheter]. / Prévalence des sténoses et thromboses des veines centrales chez les hémodialysés après un cathéter jugulaire tunnellisé.

Central venous stenosis (ST) and thrombosis (TB) related to catheter (KT) had been reported mostly for the subclavian vein. We performed a systematic cavographic study to evaluate the prevalence of these complications in 51 hemodialysis patients with present or previous history of tunneled internal jugular catheter. Each of them had used one or several KT (1.8 +/- 1.4 KT) for a mean 28 +/- 26 month cumulative time (i.e. 43,584 days total exposure time). Fifty percent of the KT were PermCath Quinton and 50% were Twincath (uncuffed) or CS 100 (cuffed) Medcomp. Twenty-seven had no ST (53%, group I), 24 had one or several significant ST (47%, group II) of superior Vena Cava (SVC, n = 4), inferior Vena Cava (IVC, n = 1), Brachio-cephalic Vein (BCV, n = 5) and subclavian vein (SC, n = 10), or a TB of SVC (n = 1), IVC (n = 3), BCV (n = 3), SC (n = 2). This accounts for an incidence of 0.55 ST or TB/1000 patient-days. Five of the twelve subclavian ST and TB had no history of previous subclavian catheter. Comparison between the two groups showed no differences according to age, time on dialysis, diabetes, hematocrit, CRP, cumulative time with catheter, catheter-related infections, type of catheter and anticoagulant treatment. IVC catheter tip's position is an important risk factor for TB and ST (4/6). Twelve group II patients had ST or TB-related symptoms, with a functional AV fistula in 9 cases. Eleven patients underwent repeated percutaneous angioplasty with 4 additional Wallstents and in 2 cases an AV fistula need to be closed. Central venous ST and TB after a jugular KT is extremely frequent, mostly without any symptoms. Consequences on peripheral or central vascular access, cost and poor long-term patency rate of angioplasty are of major importance. These results incite us to further reduce the catheter use in dialysis patients.

The Janus-faced aspect of 'dry weight'.

BACKGROUND: The goal of haemodialysis treatment in end-stage renal disease (ESRD) patients is to correct the complications of the uraemic condition. Among the main complications are fluid overload and subsequent hypertension that are corrected by achievement of 'dry weight'. We report in this study the evolution of post-dialysis body-weight and blood pressure in patients who began their HD treatment in our unit. METHODS: We studied the monthly evolution of post-dialysis body-weight (expressed as a percentage of pre-dialysis body-weight at the first HD treatment) and predialysis mean arterial pressure (MAP) over 24 months in 61 patients (21 females, mean age 59.8 years; 20% diabetic), treated with cellulosic membranes for 8 h, 3 times a week. RESULTS: The post-dialysis body-weight decreased between the onset of HD and month 2 (M2) (-4.40+/-0.52%). Then it went up, reaching -1.56+/-0.96% at M6, +0.3+/-1.27% at M12, +1.27+/-1.38% at M18 and +1.64+/-1.33% at M24. The post-dialysis body-weight increased by 6% between M2 and M24. The mean arterial pressure (MAP) decreased from 111.3+/-2.5 mmHg at M0 to 94.4+/-1.7 at M6, and then remained stable after M6. Between M2 and M6 the post-dialysis body-weight increased, whereas the predialysis MAP continued to decline. The incidence of hypotension episodes was maximal during the first 4 months of HD treatment. CONCLUSIONS: After the second month of dialysis treatment, the simultaneous increase of post-dialysis body-weight and decrease of pre-dialysis MAP are related to the effects of two processes, i.e. increased weight as the result of anabolism induced by the HD treatment on the one hand and normalization of blood pressure by fluid removal on the other. Continuous clinical assessment of the patient is necessary to provide adequate prescription of post-dialysis body-weight. During the first months of HD treatment, the nephrologist, like Janus, is a double-faced gatekeeper: he must be willing to decrease post-dialysis weight to achieve 'dry weight' and to normalize blood pressure, but he must also be prepared to increase it to compensate for anabolism and to avoid episodes of hypotension.

Is post-dialysis urea rebound significant with long slow hemodialysis?

BACKGROUND: According to previous studies, postdialysis urea rebound (PDUR) is achieved within 30-90 min, leading to an overestimation of Kt/V of between 15 and 40% in 3- to 5-hour dialysis. The purpose of the study was to assess the impact of PDUR on the urea reduction ratio (URR), Kt/V and normal protein catabolic rate (nPCR) with long 8-hour slow hemodialysis. METHODS: This study was performed in 18 patients (13 males/5 females), 62.5 +/- 11.7 years of age, hemodialyzed for 3-265 months. Initial nephropathies were: 3 diabetes; 2 polycystic kidney disease; 3 interstitial nephritis; 2 nephrosclerosis; 3 chronic glomerulonephritis, and 5 undetermined. Residual renal function was negligible. The dialysis sessions were performed using 1- to 1.8-m2 cellulosic dialyzers during 8 h, 3 times a week. Blood flow was 220 ml/min, dialysate flow 500 ml/min, acetate or bicarbonate buffer was used. Serial measurements of the urea concentration were obtained before dialysis, immediately after dialysis (low flow at t = 0), and at 5, 10, 20, 30, 40, 60, 90 and 120 min, and before the next session. The low-flow method was used to evaluate the access recirculation, second-generation Daugirdas formulas for Kt/V, and Watson formulas for total body water volume estimation. The difference between the expected urea generation (UG) and urea measured after dialysis (global PDUR) defines net PDUR (n-PDUR). RESULTS: The n-PDUR usually became stable after 58 +/- 25 (30-90) min. Its mean value was 17 +/- 10% of the 30-second low-flow postdialysis urea (3.9 +/- 2 mmol/l). This small postdialysis urea value and the importance of UG in comparison with shorter dialysis justify the use of n-PDUR. Ignoring n-PDUR would lead to a significant 4% overestimation (p < 0.001) of the URR (79 +/- 7 vs. 76 +/- 8%), 12% of Kt/V (1.9 +/- 0.4 to 1.7 +/- 0.38) and 4% of the nPCR (1.1 +/- 0.3 to 1.05 +/- 0.3). n-PDUR correlated negatively with postdialysis urea (r = 0.45 p = 0.05), positively with URR (r = 0.31 p = 0.01) and Kt/V (r = 0.3 p = 0.03) but not with K, and negatively with the urea distribution volume (r = 0.33 p = 0.05). Mean total recirculation, ultrafiltration rate, predialysis urea levels and urea clearance did not correlate with n-PDUR. CONCLUSION: We found a significant PDUR in long-slow hemodialysis after a mean of 1 h after dialysis. This PDUR has a less important impact upon dialysis delivery estimation than short 3- to 5-hour hemodialysis, especially for the lower Kt/V or URR ranges. This is explained by the low-flux, high-efficiency, and long-term dialysis. Its inter-individual variability incites us to calculate PDUR on an individual basis.

Hemodialysis trends in time, 1989 to 1998, independent of dose and outcome.

The 1989 Morbidity, Mortality, and Prescription of Dialysis Symposium (Dallas, TX) deeply modified the way of prescribing and delivering hemodialysis (HD) in the United States, as elsewhere. Among strategies emerging for end-stage renal disease treatment improvement, increasing the delivered dose has been the central issue, whereas the session time effect has remained an unsettled question. The purpose of this article is to analyze the trends in HD session time over the last decade in Tassin, France, and elsewhere and their relationship to outcome, independent of dialysis dose. The published data indicate that in the United States, there has been an increase in session time. Outside the United States, where session time had been somewhat longer, there has been either no change or a decrease in time without apparent ill effects. The dialysis dose, as measured by the urea Kt/V, has increased everywhere because improved technology allows for efficient toxin removal within a very short dialysis session. In Tassin, a recent limited experience of high-dose shortened dialysis did not show a significant short-term survival difference, but an impaired control of blood pressure (BP) and nutrition. Thus far, the highest HD long-term survival rates have been reported by the groups that used the largest doses and the longer times of HD. Effects of dose and time are, at this point, impossible to disentangle. A longer dialysis time improves extracellular volume (ECV) and BP control and decreases cardiovascular mortality. Shortening the HD session leads to impaired control of BP and increasing cardiovascular morbidity (by far the first cause of mortality on HD). In the future, the length of dialysis session should be governed by the demand of BP control.

Central venous catheters for haemodialysis: looking for optimal blood flow.

Central venous catheters are commonly used for haemodialysis patients and represent, in our centre, about 15% of the permanent vascular accesses with a total number of more than 230 central venous catheters over the last 10 years. Inadequate blood flow may occur and upsets the nurses, the patients, and the nephrologist. The aim of this study was to identify the factors of the catheter dysfunction. We studied prospectively 25 chronic haemodialysed patients with central venous catheters, 14 women and 11 men, 65 +/- 16 (55-89) years of age, treated with haemodialysis for 6.7 +/- 7 (1-26) years. Catheters were tunnelled silicone twin catheters (Permcath Quinton n = 18, Twincath Hemotec n = 7) in right (n = 19) and left internal jugular (n = 6) inserted by percutaneous Seldinger techniques. We studied the localization of the catheter tip (superior vena cava, right atrium, right ventricular, inferior vena cava), the central venous pressure before and after haemodialysis, the blood pressure (BP) before and after haemodialysis, the interdialytic weight gain, the number of symptomatic hypotensions during the 10 last dialyses. The patients were divided into two groups: group I with usual adequate catheter function (n = 18) and group II with frequent dysfunctions (n = 7). Central venous pressure before dialysis was significantly higher in group I with adequate blood flow and the catheter's tip was more frequently found localized in the right cardiac cavities than in the vena cava. When central venous pressure before dialysis was over 5 mmHg, no dysfunction occurred. Blood pressure was not different between the two groups. We found no correlation between central venous pressure and BP, interdialytic weight gain and symptomatic hypotensions. We could not predict the central venous pressure from the mean BP but there was a higher frequency of hypotensions in the hypovolaemic patients. Optimal haemodynamic conditions will be provided by a catheter tip in the right cardiac cavities and a central venous pressure over 5 mmHg which can be provided with vascular filling or dry weight revaluation.

Hypertension arterielle apres transplantation renale : Influence du profil tensionnel au stade de dialyse

L'objectif de ce travail cooperatif est d'etudier l'influence d'une hypertension pre-existante en dialyse (D); sur la frequence de l'hypertension arterielle (HTA) chez les transplantes renaux (TR); et de definir ses caracteristiques cliniques

Clinical assessment of dry weight.

Unsatisfactory control of blood pressure (BP) leading to an increased rate of cardiovascular events is the main cause of mortality in haemodialysis. BP control has deteriorated since haemodialysis session times have been reduced. Inadequate BP control most often is due to a failure to achieve and maintain dry weight. Dry weight and normotension have been gradually omitted in the goals of dialysis, satisfactory dialysis being reduced to an 'adequate' urea Kt/V. Ideal dry body weight needs a reappraisal. What is dry weight? How should it be clinically assessed, established and maintained in patients? The problems encountered in estimating dry weight can be solved at the bedside in most cases. The additional laboratory, echography and impedancemetry methods are research tools that hopefully can be made simpler and lower in cost so they can be used everyday at the bedside. In the mean time, with the exception of ambulatory blood pressure measurement, one must rely on careful and repeated clinical observation to determine and maintain dry weight.

Segmental necrosis of ascending colon in haemodialysis patients.

A segmental necrosis of the ascending colon sometimes affecting the terminal ileum was observed 13 times in 12 end-stage renal disease patients over a 5400 patient-years observation period. In all but three cases the patient was operated within 24 h of onset of the abdominal pain. Three patients had a bowel perforation; nine had a limited intestinal necrosis. All underwent a partial resection or colectomy. Two died within 1 month. In all cases the mucosa was necrotic, the submucosa small vessels were congested and the mesenteric vessels were normal. Ischaemic bowel disease has been previously reported in uraemic patients, but our cases do not fit with the usual reported features of this complication. The absence of typical mesenteric infarction, vascular thrombosis, stenosis or major atherosclerotic lesions is surprising. The ascending colon topography of the lesions is very unusual. Ischaemia, constipation and other factors may play a role.

Interdialysis blood pressure control by long haemodialysis sessions.

High blood pressure (BP) is a major factor contributing to the high incidence of cardiovascular morbidity and mortality in haemodialysis (HD) patients. According to predialysis casual BP measurements, long HD has been shown to provide good BP control. To confirm this result during the period between dialysis sessions, we performed ambulatory monitoring of BP in 91 non-selected HD patients (mean age, 58.7 (14.1) years; 14% incidence of nephrosclerosis and diabetes mellitus; treatment duration, 93.0 (77.2) months; 3 x 8 h/week, cuprophane, acetate buffer in 95% of the patients). Only one patient (1.1%) was receiving an antihypertensive medication. Ambulatory BP results were systolic (S) BP, 119.4 (19.9) mmHg; diastolic (D) BP, 70.6 (12.9) mmHg; mean (M) BP, 87.6 (13.9) mmHg. These values were significantly lower than the casual predialysis BP data and close to the reference values reported by Staessen et al. in a meta-analysis including 3476 normotensive subjects. The MBP was inversely correlated with the treatment duration, but not with interdialysis weight gain. The MBP increased significantly in the last part of the interdialysis period, and this rise was not correlated with the interdialysis weight gain. The nocturnal/diurnal ratios for SBP and DBP for the HD patients (0.97 and 0.92) were higher than the reference values reported by Staessen, (0.87 and 0.83), and argued against a nocturnal decrease in BP. We found that 52.1% of the patients had an abnormal nocturnal BP fall (MBP fall < 5%). This feature worsened during the second night of the interdialysis period.(ABSTRACT TRUNCATED AT 250 WORDS)