Accelerometer-derived physical activity and sedentary time and cardiac biomarkers: The Maastricht Study.

Background: Cardiac troponins and NT-proBNP are biomarkers of cardiac injury that are used clinically in the diagnosis of myocardial infarction and heart failure. It is not known whether the amount, types and patterns of physical activity (PA) and sedentary behaviour are associated with levels of cardiac biomarkers. Methods: In the population-based Maastricht Study (n = 2,370, 51.3% male, 28.3% T2D) we determined cardiac biomarkers hs-cTnI, hs-cTnT, and NT-proBNP. PA and sedentary time were measured by activPAL and divided into quartiles [quartile 1 (Q1) served as reference]. The weekly pattern of moderate-to-vigorous PA (insufficiently active; regularly actives; weekend warriors) and coefficient of variation (CV) was calculated. Linear regression analyses were conducted with adjustment for demographic, lifestyle, and cardiovascular risk factors. Results: There was no consistent pattern between physical activity (different intensities: total, light, moderate-to-vigorous and vigorous) and sedentary time on the one hand and hs-cTnI and hs-cTnT on the other. Those with the highest levels of vigorous intensity PA had significantly lower levels of NT-proBNP. With regard to PA patterns, weekend warriors and regularly actives had lower levels of NT-proBNP but not with hs-cTnI and hs-cTnT (reference:insufficiently actives). A higher weekly moderate-to-vigorous PA CV (indicating more irregular activity) was associated with lower levels of hs-cTnI and higher levels of NT-proBNP, but not with hs-cTnT. Conclusions: In general, there was no consistent association between PA and sedentary time and cardiac troponins. In contrast, vigorous and possibly moderate-to-vigorous intensity PA, especially if done regularly, were associated with lower levels of NT-proBNP.

Peritoneal dialysis in patients with heart failure.

Both in dialysis patients and non-uremic patients heart failure is associated with an adverse prognosis. In a state of abrupt worsening of cardiac function, acute cardiogenic shock or decompensated congestive heart failure, acute kidney injury may occur, whereas in a more chronic worsening of cardiac function chronic kidney injury may occur. Recently, the term cardiorenal syndrome was adopted and defined as "a pathophysiological disorder of the heart and kidneys whereby acute or chronic dysfunction in one organ may induce acute or chronic dysfunction in the other organ". Despite better treatment techniques and the continuous development of new medications volume overload in patients with cardiorenal syndrome is difficult to treat. Especially treatment of cardiorenal syndrome type I and II is notoriously difficult. Peritoneal dialysis might be, because of the gradual fluid removal, a therapeutic option in these patients. However, data on the effect of peritoneal dialysis in patients with heart failure with fluid overload and/or renal impairment are scarce. In this review, the role of peritoneal dialysis in the treatment cardiorenal syndrome type I, II and IV will be discussed.

Peritoneal dialysis in patients with primary cardiac failure complicated by renal failure.

BACKGROUND/AIMS: Clinical outcome in cardiorenal syndrome type II and treated with peritoneal dialysis (PD). METHODS: Retrospective analysis over a period of 10 years. RESULTS: Twenty-four patients with mean age at start of dialysis of 67 ± 10 years had mean survival on dialysis of 1.03 ± 0.84 years (median survival 1.0 year). The number of hospitalizations for cardiovascular causes were reduced (13.7 ± 26.5 predialysis vs. 3.5 ± 8.8 days/patient/month postdialysis, p = 0.001). Patients who survived longer than the median survival time (n = 12) also had a reduced number of hospitalizations for all causes (3.7 ± 3.8 predialysis vs. 1.4 ± 2.1 days/patient/month postdialysis, p = 0.041), a lower age (62 ± 10 vs. 71 ± 8 years, p = 0.013) and fewer had diabetes (2 vs. 7 patients, p = 0.039), but left ventricular ejection fraction was not different. CONCLUSION: After starting PD for cardiorenal syndrome, hospitalizations for cardiovascular causes were reduced for all patients. Survival after starting PD is highly variable. Age and diabetes seem to be significant prognostic factors, but not left ventricular ejection fraction.

[Chronic renal disease as cardiovascular risk factor]. / Chronische nierziekte als cardiovasculaire risicofactor.

A lowering of the glomerular filtration rate (GFR) and/or the presence of albuminuria are signs of chronic renal disease. Both variables are for the most part independently associated with an increased risk of cardiovascular morbidity and mortality. Albuminuria is a marker of endothelial dysfunction. A decrease of the GFR is associated with non-traditional risk factors, e.g. renal anaemia, uraemic toxins due to a decrease of the renal clearance, hyperhomocysteinaemia caused by a diminished homocysteine metabolism, excessive activation of the sympathetic nervous system which is related to sleep apnoea syndrome, oxidative stress and dyslipidaemia associated with the formation of vasotoxic, oxidised LDL cholesterol. These non-traditional risk factors may, alone or in combination with traditional atherogenic risk factors (e.g. age, male gender, smoking, hypercholesterolaemia, hypertension, obesity, positive family history and diabetes mellitus), partially via endothelial dysfunction, result in harmful effects on arterial function, increasing cardiovascular morbidity and mortality. Different stages of chronic kidney disease are associated with specific risk factors, making a specific therapeutic approach essential.

Accessory veins and radial-cephalic arteriovenous fistula non-maturation: a prospective analysis using contrast-enhanced magnetic resonance angiography.

PURPOSE: To determine if large caliber accessory veins are associated with radial-cephalic arteriovenous fistula (RC-AVF) non-maturation. METHODS: RC-AVFs were created in 15 consecutive patients (radial artery and cephalic vein diameter > 2 mm, in the absence of arterial inflow or venous outflow stenoses or occlusions). Contrast-enhanced magnetic resonance angiography (CE-MRA) was performed preoperatively for the determination of vessel diameters, stenoses and occlusions. The location and caliber of accessory veins was determined. Vascular access (VA) function was monitored and all interventions required to obtain a functioning VA were recorded. Non-maturation was defined as a nonfunctional VA at 2 months after creation. The predictive value of accessory vein caliber for prediction of RC-AVF non-maturation was evaluated using receiver operating characteristic (ROC) analysis. RESULTS: Non-maturation occurred in 10 (67%) out of 15 RC-AVFs. Large caliber accessory veins (n = 4), venous stenosis (n = 3) or both (n = 2) were associated with RC-AVF non-maturation. The presence of large caliber accessory veins was the only significant predictor for RC-AVF non-maturation (p = 0.01). Preoperatively detected accessory veins with a diameter > 70% of the cephalic vein diameter, had a sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 80, 100, 100 and 91% for prediction of RC-AVF non-maturation on patient level. Accessory vein ligation and dilatation of venous stenosis resulted in an overall salvage success rate of 89% (8/9). CONCLUSION: Large caliber accessory veins are associated with RC-AVF non-maturation. Ligation of large caliber accessory veins is a successful salvage procedure in a substantial group of patients. Furthermore, ligation of these accessory veins during initial RC-AVF creation can potentially reduce non-maturation rates; and therefore, preoperative assessment of accessory veins is recommended.

Effect of upper arm brachial basilic and prosthetic forearm arteriovenous fistula on left ventricular hypertrophy.

BACKGROUND: Creation of an arteriovenous fistula (AVF) may increase left ventricular hypertrophy in the hemodialysis population. Aim of this study was to compare the effects of a brachial-basilic (BB) AVF and the prosthetic brachial-antecubital forearm loop access (PTFE) on cardiac performance. METHODS: Patients were randomized to receive BB-AVF or prosthetic brachial-antecubital forearm loop access. Before and three months after AVF creation patients underwent an echocardiographic examination. Mann-Whitney U-test was used to compare relative increase between the measured cardiac parameters for the two groups. RESULTS: Twenty-seven patients participated in the study. The relative increase in left ventricular parameters was not significantly different between the two groups. Only left ventricular end-diastolic diameter tended to be of significance. Mean blood flow through the brachial artery was 1680+/-156 and 1450+/-221 mL/min three months after surgery for the PTFE and the BB-AVF group, respectively. CONCLUSION: After three months of follow-up, changes in cardiac structure were comparable between patients with BB and PTFE AVFs. Also access flow was comparable at this time. In general, the effects of creation of a fistula on LV structure were limited. Longer follow up time may be needed to explore the long term effects of different vascular accesses on cardiac function.

Unraveling the relationship between mortality, hyponatremia, inflammation and malnutrition in hemodialysis patients: results from the international MONDO initiative.

BACKGROUND/OBJECTIVES: Hyponatremia is a risk factor for mortality in hemodialysis (HD) patients. It is not well known to which extent the comorbidities, malnutrition, fluid status imbalance and inflammation are related to hyponatremia and affect outcomes. SUBJECTS/METHODS: We studied 8883 patients from the European subset of the international MONitoring Dialysis Outcomes initiative. Nutritional and fluid statuses were assessed by bioimpedance spectroscopy. Fluid depletion was defined as overhydration⩽-1.1 l and fluid overload as overhydration>+1.1 l, respectively. Malnutrition was defined as a lean tissue index below the 10th percentile of age- and gender-matched healthy controls. Hyponatremia and inflammation were defined as serum sodium levels <135 mEq/l and C-reactive protein levels>6.0 mg/l, respectively. We used logistic regression to test for predictors of hyponatremia and Cox proportional hazards analysis to assess the association with all-cause mortality. RESULTS: Hyponatremia was predicted by the presence of malnutrition (odds ratio (OR)=1.49 (95% confidence interval (CI)=1.30-1.70), inflammation (OR=1.44 (95% CI=1.26-1.64)) and fluid overload ((>+1.1 l to +2.5 l) OR=0.73 (95% CI=0.62-0.85)) but not by fluid depletion (OR=1.34 (95% CI=0.92-1.96)). Malnutrition, inflammation, fluid overload, fluid depletion and hyponatremia (hazard ratio=1.70 (95% CI=1.46-1.99)) were independent predictors for all-cause mortality. CONCLUSIONS: In HD patients, hyponatremia is associated with malnutrition, inflammation and fluid overload. Hyponatremia maintained predictive for all-cause mortality after adjustment for malnutrition, inflammation and fluid status abnormalities. The presence of hyponatremia may assist in identifying HD patients at increased risk of death.

Association between pre hemodialysis serum sodium concentration and blood pressure: results from a retrospective analysis from the international monitoring dialysis outcomes (MONDO) initiative.

A recent study from the United Kingdom indicates an association between pre hemodialysis (HD) serum sodium (SNa(+)) and systolic and diastolic blood pressure (SBP and DBP) in chronic HD patients. We extend this analysis to an international cohort of incident HD patients. The Monitoring Dialysis Outcomes initiative encompasses patients from 41 countries. Over 2 years monthly pre-HD SNa(+) levels were used as predictors of pre-HD SBP and DBP in a linear mixed model (LMM) adjusted for age, gender, interdialytic weight gain, diabetes, serum albumin and calcium. Similar models were constructed with DBP as outcome. Analyses were carried out stratified by continent (North and South America; Europe and Asia). LMMs were also constructed for the entire observation period of 2 years, and separately the first and the second year after HD initiation. We studied 17 050 incident patients and found SNa(+) to have a significant slope estimate in the LMM predicting pre-HD SBP and DBP (ranging from 0.22 to 0.29 and 0.10 to 0.21 mm Hg per mEq l(-1), respectively, between the continents). The findings were similar in subsets of SBP and SNa(+) tertiles, and separately analyzed for the first and second year. Our analysis shows an independent association between SNa, SBP and DBP in a large intercontinental database, indicating that this relation is a profound biological phenomenon in incident and prevalent HD patients, generalizable to an international level and independent of SBP and DBP magnitude.

Relation between steroid dose, body composition and physical activity in renal transplant patients.

BACKGROUND: Fat mass is increased in renal transplant (RTx) patients, which may have untoward metabolic and cardiovascular effects. The influence of steroids on body composition (BC), resting energy expenditure (REE), and substrate oxidation rates was assessed in stable RTx patients in a cross-sectional design. Also, the relation between physical activity and nutrient intake, respectively, and body composition was studied. METHODS: 77 RTx patients (42 males, 35 females) were studied. Twenty-one patients were on 10 mg and 27 patients on 5 mg maintenance steroid dose; 29 patients were receiving steroid-free immunosuppression. Assessed were BC (DEXA, anthropometry), REE and substrate oxidation (indirect calorimetry), physical activity (Baecke questionnaire), and nutrient intake (dietary records). RESULTS: BC was not different between the 0-, 5-, and 10-mg steroid group, and no relationship existed between cumulative dose of steroids and BC. REE and substrate oxidation also did not differ between the various groups, apart from a small increase in glucose and decrease in lipid oxidation in female patients using 5-mg steroids. Especially in females, leisure time physical activity was positively related with the percentage lean body mass (r=0.571, P=0.004) and inversely related with fat mass (r= -0.588, P=0.003). Nutrient intake and BC (corrected for physical activity) were not related. CONCLUSIONS: No relation was observed between daily and cumulative steroid dosage and BC and between daily steroid dose and REE and substrate oxidation in RTx patients. Especially in female patients, physical activity level and the percentage of lean body mass concluded and body fat were significantly related.

Strategies for improving hemodynamic stability in cardiac-compromised dialysis patients.

In hemodialysis patients, structural changes at all levels of the cardiovascular system are common. The presence of these cardiovascular changes is a risk factor for the development of intradialytic hypotension. This explains the clinical observation that the incidence of symptomatic hypotension is high in elderly hemodialysis patients, who often have a history of long-standing hypertension and atherosclerosis, and in hemodialysis patients with cardiovascular disease. With an increasing number of cardiovascular compromised dialysis patients, special attention should be given to this group of patients. As the age of patients on hemodialysis increases steadily, it is a challenge to provide comfortable treatment in these patients by reducing the incidence of symptomatic hypotensive periods. This article describes the use of relatively new and simple clinical maneuvers to reduce the incidence of symptomatic hypotension.

Effect of dialysate temperature on energy balance during hemodialysis: quantification of extracorporeal energy transfer.

An impaired vascular response is implicated in the pathogenesis of dialysis-induced hypotension, which is at least partly related to changes in extracorporeal blood temperature (Temp). However, little is known about changes in core Temp and differences in energy balance between standard and cool dialysis. In this study, core Temp and energy transfer between extracorporeal circuit and patient, as well as the blood pressure response, were assessed during dialysis with standard (37.5 degrees C) and cool (35.5 degrees C) Temp of the dialysate. Nine patients (4 men, 5 women; mean age, 69 +/-10 [SD] years) were studied during low- and standard-Temp dialysis, each serving as his or her own control. Bicarbonate dialysis and hemophane membranes were used. Energy transfer was assessed by continuous measurement of Temp in the arterial (Tart) and venous side (Tven) of the extracorporeal system according to the formula: c. rho.Qb*(Tven - Tart)*t, where c = specific thermal capacity (3.64 kJ/kg* degrees C), Qb = extracorporeal blood flow, rho = density of blood (1,052 kg/m3), and t = dialysis time (hours). Core Temp was also measured by Blood Temperature Monitoring (BTM; Fresenius, Bad Homburg, Germany). Core Temp increased during standard-Temp dialysis (36.7 degrees C +/- 0.3 degrees C to 37.2 degrees C +/- 0.2 degrees C; P < 0.05) despite a small negative energy balance (-85 +/- 43 kJ) from the patient to the extracorporeal circuit. During cool dialysis, energy loss was much more pronounced (-286 +/- 73 kJ; P < 0.05). However, mean core Temp remained stable (36.4 degrees C +/- 0.6 degrees C to 36.4 degrees C +/- 0.3 degrees C; P = not significant), and even increased in some patients with a low predialytic core Temp. Both during standard and cool dialysis, the increase in core Temp during dialysis was significantly related to predialytic core Temp (r = 0.88 and r = 0.77; P < 0.05). Systolic blood pressure (RR) decreased to a greater degree during standard-Temp dialysis compared with cool dialysis (43 +/- 21 v 22 +/- 26 mm Hg; P < 0.05), whereas diastolic RR tended to decrease more (15 +/- 10 v 0 +/- 19 mm Hg; P = 0.07). Core Temp increased in all patients during standard-Temp dialysis despite a small net energy transfer from the patient to the extracorporeal system. Concluding, Core Temp remained generally stable during cool dialysis despite significant energy loss from the patient to the extracorporeal circuit, and even increased in some patients with a low predialytic core Temp. The change in core Temp during standard and cool dialysis was significantly related to the predialytic blood Temp of the patient, both during cool- and standard-Temp dialysis. The results suggest that the hemodialysis procedure itself affects core Temp regulation, which may have important consequences for the vascular response during hypovolemia. The removal of heat by the extracorporeal circuit and/or the activation of autoregulatory mechanisms attempting to preserve core Temp might be responsible for the beneficial hemodynamic effects of cool dialysis.

Role of bioimpedance spectroscopy in assessment of body water compartments in hemodialysis patients.

Bioimpedance spectroscopy (BIS) has been advocated as a tool to assess fluid status in hemodialysis (HD) patients. However, uncertainty remains about the reliability of BIS in patients with abnormalities in fluid status. Aims of the study are to assess the agreement between total-body water (TBW) and extracellular volume (ECW) measured by BIS and tracer dilution (deuterium oxide [D(2)O] and sodium bromide [NaBr]), the influence of the relative magnitude of water compartments (expressed as TBW(D(2)O) and ECW(NaBr):body weight) on the agreement between BIS and tracer dilution, and the ability of BIS to predict acute changes in fluid status. BIS and tracer dilution techniques were performed in 17 HD patients before a dialysis session. Moreover, the relation between BIS and gravimetric weight changes was assessed during both isolated ultrafiltration and HD. Correlation coefficients between TBW and ECW measured by BIS and tracer dilution were r = 0.71 and r = 0.71, respectively. Mean differences (tracer-BIS) were 6.9 L (limits of agreement, -1.5 to 21.6 L) for TBW and 2.3 L (limits of agreement, -1.7 to 9.7 L) for ECW. There was a significant relationship between the relative magnitude of TBW and ECW compartments and disagreement between BIS and tracer dilution (r = 0.65 and r = 0.77; P < 0.05). During both isolated ultrafiltration and HD, there was a significant relation between gravimetric changes and change in ECW(BIS) (r = 0.83 and r = 0.76; P < 0.05), but not with change in TBW(BIS). In conclusion, agreement between BIS and tracer dilution techniques in the assessment of TBW and ECW in HD patients is unsatisfactory. The discrepancy between BIS and dilution techniques is related to the relative magnitude of body water compartments. Nevertheless, BIS adequately predicted acute changes in ECW during isolated ultrafiltration and HD, in contrast to changes in TBW.

Optimizing dialysis dose by increasing blood flow rate in patients with reduced vascular-access flow rate.

Dialysis efficacy indexed by Kt/V can generally be augmented by increasing the dialyzer blood flow rate. However, increasing the dialyzer blood flow rate may lead to vascular-access recirculation (AR) in patients with a compromised vascular-access flow rate. This can have an attenuating effect on dialysis efficacy. The aim of the present study is to investigate the effect of dialyzer blood flow rates of 200, 300, and 400 mL/min on AR and Kt/V in 8 patients with low (<600 mL/min) and 13 patients with normal (>600 mL/min) vascular-access flow rates. AR and vascular-access flow rate were determined using an ultrasound saline dilution technique, and session-delivered Kt/V was computed using an on-line dialysate urea monitor. AR was minor and only observed in 4 patients in the low vascular-access flow rate group (0.9% +/- 0.6%) at dialyzer blood flow rates of 200 mL/min (1 patient), 300 mL/min (2 patients), and 400 mL/min (3 patients) and 4 patients in the normal vascular-access flow rate group (1.2% +/- 1.1%) at dialyzer blood flow rates of 200 mL/min (3 patients) and 300 mL/min (1 patient). Kt/V increased with increasing dialyzer blood flow rates in both groups, and in individual cases, there was no decrease in Kt/V at greater dialyzer blood flow rates in either group. Also in those patients with minor AR, Kt/V increased at greater dialyzer blood flow rates, except in 1 patient in the low-flow group, in whom Kt/V remained unchanged at a change in dialyzer blood flow rate from 300 to 400 mL/min, whereas AR increased. From this study, it is concluded that even in patients with low access flow, increasing dialyzer blood flow rate in general leads to an increase in delivered Kt/V regardless of vascular access flow rate.

A comparison between office and ambulatory blood pressure measurements in renal transplant patients with chronic transplant nephropathy.

Hypertension is an important risk factor for chronic transplant nephropathy. Therapy is usually based on casual office blood pressure (BP) measurements. However, it is not well known how casual BP predicts 24-hour BP in this population. The main focus of this study is to compare casual office BP with 24-hour ambulatory BP monitoring in renal transplant recipients with signs of chronic transplant nephropathy. Moreover, in this group, the day-night BP profile was assessed. In 36 renal transplant recipients with incipient or progressive proteinuria or an increase in serum creatinine level greater than 20%, 24-hour ambulatory BP was performed. Patients were defined as a nondipper if the mean BP decreased by less than 10% during the nighttime period. The correlation between single office and 24-hour ambulatory BPs was 0.61 for systolic BP and 0.55 for diastolic BP (P < 0.001). The mean difference between 24-hour ambulatory and single office BPs was -4.2 +/- 18.6 mm Hg (range, -44 to 36 mm Hg) for systolic BP and -1.1 +/- 10.7 mm Hg (range, -34 to 27 mm Hg) for diastolic BP; 94.5% of patients were classified as nondippers. There was a significant relation between the nightly decline in mean arterial pressure and calculated creatinine clearance (r = 0.34; P < 0.05). In conclusion, in renal transplant recipients with chronic transplant nephropathy, a large difference between office and ambulatory BPs is present, with both overestimation and underestimation of 24-hour BP by office BP measurements. Moreover, a severely disturbed day-night BP rhythm was observed. In transplant recipients with compromised graft function, office BP may not reflect 24-hour BP adequately, and ambulatory BP measurements should be considered.

New techniques to determine fluid status in hemodialyzed patients.

In this paper, several newly developed techniques for the estimation of the fluid status in hemodialysis patients were reviewed. Whereas echography of the inferior caval vein and the measurement of ANP and cGMP levels merely provide information about the intravascular volume, conductivity measurements are able to detect changes in the extracellular and intracellular compartments without being able to differentiate between the intravascular and interstitial fluid spaces. Echography of the inferior caval vein as a tool to assess over- and underhydration has been successfully validated against objective standards as right atrial pressure, total blood volume and the change in hemodynamic parameters during dialysis. Conductivity measurements were significantly related to vena cava measurements before and after dialysis. Whereas ANP levels were significantly related to the vena cava diameter before dialysis, in another group of patients, only a significant relation between the vena cava diameter and cGMP was observed in patients with normal left atrial hemodynamics, whereas they were not in patients with a dilated left atrium. Furthermore, in normovolemic patients with mitral insufficiency, ANP levels after dialysis remained increased compared to patients without mitral insufficiency, suggesting that, in addition to volume expansion, also altered left atrial hemodynamics influence the release of cGMP and ANP. Conductivity measurements and ANP before and after dialysis were not related, whereas only cGMP after dialysis was significantly related to conductivity measurements. ANP and cGMP were not related to the change in hemodynamic parameters during dialysis, questioning their reliability in the assessment of underhydration.

The hemodynamic effect of different ultrafiltration rates in patients with cardiac failure and patients without cardiac failure: comparison between isolated ultrafiltration and ultrafiltration with dialysis.

OBJECTIVE: The increasing number of dialysis patients with cardiovascular diseases will lead to an increase in the incidence of intradialytic hypotension. Intradialytic hypotension is determined by changes in plasma volume, changes in vascular reactivity and structural cardiovascular changes. In this study the effect of two different ultrafiltration rates (UF-rate), i. e. 500 and 1000 ml/h, on plasma volume, extracellular volume and arterial blood pressure was studied during different treatments of 2 hours combined ultrafiltration + hemodialysis (UF+HD) and 2 hours isolated ultrafiltration (i-UF). PATIENTS AND METHODS: 15 Patients, 8 patients with cardiac failure, CFpts (NYHA classification III and IV) and 7 patients without cardiac failure (NCFpts) were investigated during a standardized dialysis treatment. RESULTS: The decrease in plasma volume and decrease in extracellular volume was comparable both between i-UF and UF+HD and comparable between CFpts and NCFpts and was only dependent on the UF-rate. i-UF resulted in minor blood pressure changes in both CFpts and NCFpts. In CFpts UF+HD resulted in a significant decrease in systolic blood pressure (SBP) at both UF-rates while in NCFpts SBP decreased significantly only at the higher UF-rate during UF-HD. Although there were no significant differences in hemodynamic stability during the different treatment modalities between CFpts and NCFpts, the decrease in SBP in CFpts at the higher UF-rate during UF+HD was much more pronounced. CONCLUSION: From this clinical study we conclude that differences in hemodynamic stability between i-UF and UF+HD and between CFpts and NCFpts are not related to differences in plasma volume preservation. Other factors like different changes in vascular reactivity and in CFpts structural cardiovascular changes might be responsible for the observed differences.

Acute pyelonephritis: a cause of acute renal failure?

Two patients with acute renal failure due to acute pyelonephritis are described. Examination of the renal biopsy showed normal glomeruli, severe interstitial neutrophilic infiltration and edema with no signs of acute tubular necrosis. Until now, only twelve biopsy-proven proven cases have been reported. A review of the literature on acute renal failure due to acute pyelonephritis is presented.

[Cardiovascular diseases in dialysis patients]. / Cardiovasculaire ziekten bij dialysepatiënten.

Cardiovascular morbidity and mortality are higher among dialysis patients than among the general population. The cardiovascular problems often exist before the start of dialysis. Their pathogenesis is multifactorial in dialysis patients also. The prevalence of left ventricular hypertrophy is strongly increased. Adequate therapy may lead to partial remission. Cardiac ischaemia is frequent among dialysis patients and may occur without severe coronary artery disease. The prognosis of myocardial infarction in dialysis patients is poorer than in the general population. There is no proven difference between the various dialysis techniques regarding cardiovascular morbidity and mortality, while kidney transplantation may have a beneficial effect. Early diagnosis and treatment aimed at risk factors for cardiovascular disease are indicated.

[Hypotensive periods during hemodialysis]. / Hypotensieve perioden tijdens hemodialyse.

Hypotensive periods occur frequently during a haemodialysis session. The pathogenesis of intradialytic hypotension is multifactorial. The initiating factor is a decline in blood volume. Important contributory factors are inadequate vascular reactivity during haemodialysis and structural cardiovascular abnormalities. Compared with 'standard' haemodialysis, vascular reactivity is clearly increased during isolated ultrafiltration, haemodialysis with lowered fluid temperature (e.g. 36 degrees C), and haemofiltration. The single most important factor explaining these differences in vascular response is the thermal energy balance during the various treatment modalities. With a critical reduction of cardiac filling, the Bezold-Jarish reflex may occur, leading to paradoxical vasodilation and bradycardia.

[Acute renal replacement therapy in the intensive care unit]. / Acute nierfunctievervangende therapie op de intensive-careafdeling.

On the intensive care department the most frequently used acute renal replacement techniques are intermittent haemodialysis and continuous haemofiltration. Although continuous techniques appear to have distinct advantages in the treatment of critically ill patients, no consistent differences in mortality have been found between continuous and intermittent treatment modalities. Due to uncertainty in this area, the use of unmodified cellulose membranes is probably best avoided. No good randomised studies are available with regard to the starting time of renal replacement techniques in critically ill patients. However, generally speaking a 'late' start should be avoided. With continuous techniques, the filtration volume should not be below 35 ml/kg/h. Although continuous (high-volume) filtration techniques may contribute to an improvement in the haemodynamics, the mechanisms behind this phenomenon remain unclear. At present, no randomised studies are available which have shown a beneficial effect of continuous techniques on the survival of critically ill patients without manifest renal insufficiency being demonstrated.