Cardiovascular Risk Related to Glomerular Hyperfiltration in Nondiabetic Individuals: Increasing Visibility is Crucial.

Glomerular hyperfiltration (GHF), defined by different estimation formulas, has been widely studied as a predictor of proteinuria and progression to chronic kidney disease (CKD) in diabetic patients. GHF is also an important cardiovascular (CV) risk factor and is related to allcause mortality in non-diabetic populations; however, the upper limit of glomerular filtration rate (GFR) above which it indicates the presence of GHF is weakly defined. This higher risk is as high as in the intermediate stages of CKD and is greater than the presence of diabetes or smoking and is still present in non-albuminuria patients. The original Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) estimation GFR formula showed lower error at higher glomerular filtration (GF) values, was the most used in population studies, and behaved as a better risk predictor. In our review (including approximately 3.6 million individuals), higher GFR values related to increased mortality risk varied from 106.6 to 113.7 ml/min, which are usually not considered risk values for standard guidelines in non-albuminuric patients. However, the lack of consensus on a GF cutoff value, as well as its variability due to sex and progressive reduction with age, affect the knowledge of this serious phenomenon in clinical practice. Although the elderly population is not exempted from the effects of GHF, the search for this phenomenon should be intensified in middle-aged populations because of their lower disease burden, where this situation may be more evident, and the possibility of reversing the consequences is greater. A population group often considered healthy includes obese people, essential hypertensives, smokers, and carriers of fatty liver, where the GHF phenomenon is frequent and is associated with CV disease, kidney disease, and higher mortality. Increasing its visibility by the medical community is essential to reduce the effects of GHF, emphasizing more frequent controls and implementing general measures that include strict control of hypertension, Na restriction, rich in vegetables diets and increased physical activity. Initiatives to confirm the beneficial effects of sodium-glucose cotransporter-2 inhibitors to treat isolated GHF would be an important breakthrough in reducing the severe consequences of this phenomenon.

Protective Effect of Autologous Arteriovenous Fistulae Against Oxidative Stress in Hemodialyzed Patients.

INTRODUCTION:  Oxidative stress (OS) is ubiquitous in chronic kidney disease (CKD) and is exacerbated by hemodialysis (HD). OS is also associated with anemia, malnutrition, and cardiovascular (CV) disease and is an independent predictor of mortality and morbidity in patients undergoing HD. HD vascular access (VA) types are strongly correlated with CKD patient outcomes. Prolonged use of central venous catheters (CVC) for HD and arteriovenous grafts (AVG) promotes inflammation and OS. However, the effects of the VA type on OS have been poorly studied in HD patients. This study investigated OS prevalence in an HD population to determine the relationship between the VA type and HD. METHODS: The oxidative stress index (OSI) was used to assess the HD patients' OS status. OSI summarizes information derived from the reactive oxygen metabolites (d-ROMs) fast test and the plasma antioxidant test (PAT) in a single value, using the hydrogen peroxide concentration (for d-ROMs) and ascorbic acid (for PAT) as reference standards. The OSI was created to indicate how far the OS status deviates from normal (i.e., fully compensated oxidative balance). An index increase may be from an increase or decrease in peroxide or antioxidant concentrations. Patients undergoing chronic HD were evaluated by dividing the cases according to the OSI status: normal (N-OSI), borderline (BL-OSI), high (H-OSI), and very high (VH-OSI). Patients with clinical evidence of active infections were excluded. RESULTS: In total, 129 patients were included; 86.8% used high-flux dialyzers, 13.2% used hemodiafiltration (HDF), and 24.5% were diabetic. An altered OSI was observed in 86 of 129 patients (66.7%). An increased OSI correlated with a significant increase in d-ROMs (r = 0.420) and PAT (r = 0.710). There were no differences between sex, diabetes status, age, dialysis vintage, or dialysis modalities. d-ROMs were inversely correlated with hemoglobin levels (r = -0.209). The iron dose by month correlated with the OSI (r = 0.189) and was significantly lower in the N-OSI group. N- and BL-OSI patients had a significantly higher rate of autologous arteriovenous fistula (AVF) compared to the other groups, and VH-OSI patients had a higher rate of permanent tunneled CVC. CONCLUSION:  Most HD patients had more OS, indicated by the OSI scores. In chronic HD patients, AVF had a protective effect against imbalanced peroxidation-antioxidation.

Potential Novel Benefits of Sodium Restriction in Chronic Kidney Disease.

Chronic kidney disease is a global public health issue, and it has been considered as the epidemic of the 21st century. Therefore, all initiatives addressed to slow down the evolution and complications of this condition should be well received. While the effects of salt reduction on cardiovascular disease have some controversial issues, in chronic kidney disease, such a policy is beneficial in multiple aspects. In chronic kidney disease patients, dietary sodium restriction is regularly recommended to control extracellular fluid expansion, hypertension and cardiovascular risk. Instead, the effects of sodium reduction on chronic kidney disease progression are still controversial. In the last years, potentially beneficial effects of a low sodium diet on chronic kidney disease evolution have emerged. Firstly, recent magnetic resonance-based findings of increased Na depots in skin and muscle associated with renal function, ageing and sodium intake open a vast body of investigation as a potential tool for monitoring effects of sodium restriction. In this narrative review, we also discussed novel aspects of sodium restriction in chronic kidney disease to manage metabolic acidosis as well as renal effects on fibroblast growth factor 23 or gut microbiota. Beyond current evidence, these approaches showed that common findings of kidney failure environment such as sodium -sensitivity, micro-inflammation, arterial stiffness metabolic acidosis and sarcopenia could be delayed controlling dietary sodium. Additional studies are now needed in populations with chronic kidney disease to confirm these new findings, addressed to slow down the evolution and complications of this condition.

Central-To-Peripheral Arterial Stiffness Gradient in Hemodialyzed Patients Depends on the Location of the Upper-limb Vascular Access.

BACKGROUND: Pulse wave velocity ratio (PWV-ratio), a measure of central-to-peripheral arterial stiffness gradient, is calculated as a quotient between carotid-femoral and carotid-radial PWV (cf-PWV/cr-PWV). This new index has been reported to be significantly associated with increased mortality in hemodialyzed patients. Since several reports showed differences in arterial stiffness regarding the pathway where the vascular access (VA) is, the purpose of this research was: a) to compare arterial stiffness values obtained in the left and right sides of the body in hemodialyzed and non-hemodialyzed patients, and b) to analyze PWV-ratio values obtained on the side of the body where the VA was placed and compare them to its contralateral intact side. Since it is difficult to adequately measure cr-PWV in patients with a VA in the forearm, we measured the carotid- brachial PWV (cb-PWV) and used it to calculate PWV-ratio (cf-PWV/cb-PWV). METHODS: A Pearson's correlation and Bland & Altman analysis were performed in hemodialyzed (n=135) and non-hemodialyzed (n=77) patients, to quantify the equivalence between arterial stiffness parameters (cf-PWV, cb-PWV, PWV-ratio) obtained on each side of the body with respect to its contralateral side. RESULTS: We conclude that PWV-ratio values measured on the side where the VA is placed were significantly higher than those obtained in its contralateral side, in hemodialyzed patients included in this research. Moreover, cf-PWV, cb-PWV and PWV-ratio values obtained on one side of the body were always highly correlated with its contralateral side. CONCLUSION: According to this research, any research involving PWV-ratio should always consider the observed territory.

Aortic-Radial Pulse Wave Velocity Ratio in End-stage Renal Disease Patients: Association with Age, Body Tissue Hydration Status, Renal Failure Etiology and Five Years of Hemodialysis.

INTRODUCTION: The etiology of the end-stage renal disease (ESRD) and the hydration status may be involved in the arterial stiffening process observed in hemodialyzed patients. The ratio between carotid-femoral and carotid-radial pulse wave velocity (PWV ratio) was recently proposed to characterize the patient-specific stiffening process. AIMS: to analyze: (1) the PWV-ratio in healthy and hemodialyzed subjects, analyzing potential changes associated to etiologies of the ESRD, (2) the PWV-ratio and hydration status using multiple-frequency bioimpedance and, (3) the effects of hemodialysis on PWV-ratio in a 5-year follow-up. METHODS: PWV-ratio was evaluated in 151 patients differentiated by the pathology determining their ESRD. Total body fluid (TBF), intra and extra cellular fluid (ICF, ECF) were measured in 65 of these patients using bioelectrical-impedance. The association between arterial, hemodynamic or fluid parameters was analyzed. PWV-ratio was evaluated in a group of patients (n = 25) 5 years later (follow-up study). RESULTS: PWV-ratio increased in the ESRD cohort with respect to the control group (1.03 ± 0.23 vs. 1.31 ± 0.37; p < 0.001). PWV-ratio in the diabetic nephropathy group was higher than in all other etiological groups (1.61 ± 0.33; p < 0.05). PWV-ratio was associated with TBF (r = -0.238; p < 0.05), ICF (r = -0.323; p < 0.01), ECF/ICF (r = 0.400; p < 0.001) and ECF/TBF (r = 0.403; p < 0.001). PWV-ratio calculated in ESRD patients in 2007 increased 5 years later (1.14 ± 0.32 vs. 1.43 ± 0.44; p < 0.005). CONCLUSIONS: PWV-ratio increased the most in patients with diabetic nephropathy. PWV ratio was significantly associated with age and body hydration status, but not with the blood pressure. PWV-ratio could be considered a blood pressure-independent parameter, associated with the age and hydration status of the patient.

Hemodialysis Decreases the Etiologically-Related Early Vascular Aging Observed in End-Stage Renal Disease: A 5-Year Follow-Up Study.

AIMS: To analyze the early vascular aging (EVA) in end-stage renal disease (ESRD) patients, attempting to determine a potential association between EVA and the etiology of ESRD, and to investigate the association of hemodialysis and EVA in ESRD patients during a 5-year follow-up period. METHODS: Carotid-femoral pulse wave velocity (cfPWV) was obtained in 151 chronically hemodialyzed patients (CHP) and 283 control subjects, and in 25 CHP, who were followed-up after a 5-year lapse. RESULTS: cfPWV increased in ESRD patients compared to control subjects. The cfPWV-age relationship was found to have a steeper increase in ESRD patients. The highest cfPWV and EVA values were observed in patients with diabetic nephropathy. Regression analysis demonstrated a significant reduction of the EVA in HD patients on a 5-year follow-up. CONCLUSION: Patients in ESRD showed higher levels of EVA. cfPWV and EVA differed in ESRD patients depending on their renal failure etiology. CHP showed an EVA reduction after a 5-year follow-up period.

Análisis comparativo de la rigidez arterial evaluada en forma no invasiva en pacientes hemodializados / Comparative analysis of arterial stiffnes non invasively evaluated in hemodialyzed patients

INTRODUCCIÓN: Los cambios de la rigidez arterial de pacientes hemodializados se producen en vasos elásticos y musculares pero sólo la Velocidad de la Onda del Pulso (VOP) aórtica ha demostrado ser un índice de alto valor pronóstico. Lo cual deja de lado a las arterias musculares. OBJETIVOS: Los objetivos del estudio fueron: a) medir la VOP aórtica y la carotido-radial de pacientes hemodializados, y b) repetir el análisis anterior en la misma cohorte 5 años después, comparando cuatro índices diferentes de rigidez arterial. MATERIAL Y MÉTODOS: A 23 pacientes hemodializados se les evaluó la VOP aórtica (VOPcf), la carotido-radial (VOPcr) y se calculó: la VOP centro-periférica (VOPcp), la diferencia (ΔVOP), el desacople de VOP y su cambio porcentual (%VOP). Las evaluaciones se hicieron en 2007 (Tiempo 1) y en 2012 (Tiempo 2). RESULTADOS: La VOPcp mostró un aumento significativo entre la evaluación realizada entre el Tiempo 1 y el 2 (de 1.1±0.3 a 1.4±0.4; p<0.01). En los mismos tiempos ΔVOP mostró que los valores se incrementaban en términos negativos (de -0.9±3.0 a -2.7±2.9; p<0.05). El desacople de la rigidez centro-periférica mostró un significativo aumento (valores negativos) entre el Tiempo 1 y 2 (de 0.0±0.1 a -0.1±0.1; p<0.02). El %VOP entre ambas mediciones (valores negativos) mostró un significativo aumento (de -4.8±22.0 a -21.5±24.2; p<0.05). CONCLUSIONES: En la presente investigación los índices de rigidez obtenidos en pacientes hemodializados, incluyendo arterias tanto elásticas y musculares, mostraron diferencias estadísticamente significativas cuando se compararon dos mediciones separadas por cinco años. Sin embargo los niveles de significación no fueron similares

OBJECTIVES: Changes in arterial stiffness in hemodialysis patients occur both, in elastic and muscular vessels but only the aortic Pulse Wave Velocity (PWV) has demonstrated to be a high prognostic value index, however, muscular arteries are not involved in the aortic PWV measurement. The purpose of this research was: a) to evaluate the aortic and carotid-radial PWV of hemodialysis patients, b) to repeat these measurements in the same cohort after 5 years comparing four different arterial stiffness indexes. METHODS: 23 hemodialyzed patients carotid-femoral PWV (PWVcf) and carotid-radial (PWVcr) were evaluated and calculations were as follows: PWV ratio, PWV difference (/PWV), PWV mismatch and PWV percentage change (%PWV). These evaluations were performed using data obtained in 2007 (Time 1) and 2012 (Time 2). RESULTS: PWV ratio showed a significant increase between measurements performed in Time 1 and 2 (from 1.1±0.3 to 1.4±0.4; p≤0.01). Similar increases in negative terms were found when /PWV was calculated from -0.9±3.0 to -2.7±2.9; p≤0.05) Calculated values of PWV mismatch increased significantly (negative values) between Time 1 and 2 (from 0.0±0.1 to -0.1±0.1; p≤0.02) Percent changes of PWV between Time 1 and 2 (negative values) showed a significant increase (from -4.8±22.0 to -21.5±24.2; p≤0.05). CONCLUSIONS: Stiffness indexes, obtained in hemodialyzed patients including both elastic and muscular arteries used in this research showed statistically significant differences when two measures with 5 years interval were compared. However significance levels were not similar

Hydration Status Is Associated with Aortic Stiffness, but Not with Peripheral Arterial Stiffness, in Chronically Hemodialysed Patients.

Background. Adequate fluid management could be essential to minimize high arterial stiffness observed in chronically hemodialyzed patients (CHP). Aim. To determine the association between body fluid status and central and peripheral arterial stiffness levels. Methods. Arterial stiffness was assessed in 65 CHP by measuring the pulse wave velocity (PWV) in a central arterial pathway (carotid-femoral) and in a peripheral pathway (carotid-brachial). A blood pressure-independent regional arterial stiffness index was calculated using PWV. Volume status was assessed by whole-body multiple-frequency bioimpedance. Patients were first observed as an entire group and then divided into three different fluid status-related groups: normal, overhydration, and dehydration groups. Results. Only carotid-femoral stiffness was positively associated (P < 0.05) with the hydration status evaluated through extracellular/intracellular fluid, extracellular/Total Body Fluid, and absolute and relative overhydration. Conclusion. Volume status and overload are associated with central, but not peripheral, arterial stiffness levels with independence of the blood pressure level, in CHP.

Hemodialysis decreases carotid-brachial and carotid-femoral pulse wave velocities: A 5-year follow-up study.

Aortic stiffness is a prognostic parameter associated with patient mortality. Vascular access creation has been shown to have effects on arterial stiffness both in the aorta and in the upper limb arteries in chronically hemodialyzed patients (CHPs). However, no longitudinal studies have been conducted in order to characterize the evolution of arterial stiffness in CHPs. The aims of this work were (a) to measure baseline pulse wave velocity (PWV) in the carotid-femoral and in right and left carotid-brachial pathways in a cohort of CHP and (b) to conduct a 5-year prospective study on the same cohort to determine possible time-related differences. Pulse wave velocity was measured both in the carotid-femoral and in the carotid-brachial pathways, and clinical and biochemical parameters were collected in 25 CHPs, which were followed up after a 5-year lapse. Right and left carotid-brachial pathway PWV values showed significant decreases after the 5-year follow-up, independently of the presence of the vascular access (P < 0.001). Additionally, baseline carotid-brachial PWV was significantly higher (P < 0.001) than values measured 5 years later for upper limbs with vascular access (11.97 ± 2.97 m/sec vs. 6.76 ± 1.48 m/sec, respectively) and without vascular access (12.25 ± 2.38 m/sec vs. 7.18 ± 1.88 m/sec, respectively). Similarly, PWV values in the carotid-femoral pathway decreased significantly (P < 0.001) over the same period (13.27 ± 2.96 m/sec vs. 9.75 ± 2.99 m/sec, respectively). The 5-year follow-up of PWV showed significant decreases in both carotid-brachial and carotid-femoral pathways. The general changes in arterial stiffness could be related to the vascular access creation, hemodialysis therapy, and to the improvement of arterial pressure management.

Nutritional Markers and Body Composition in Hemodialysis Patients.

The aims of this study were to analyse body composition, to detect the presence of undernutrition, and to establish a relationship between undernutrition and the biological markers routinely used as indicators of nutritional status in hemodialysis (HD) patients (pts). We used a body composition monitor (BCM) that expresses body weight in terms of lean tissue mass (LTM) and fat tissue mass (FTM) independent of hydration status. From nine HD units, 934 pts were included. Undernutrition was defined as having a lean tissue index (LTI = LTM/height(2)) below the 10th percentile of a reference population. Biochemical markers and parameters delivered by BCM were used to compare low LTI and normal LTI groups. Undernutrition prevalence was 58.8% of the population studied. Low LTI pts were older, were significantly more frequently overhydrated, and had been on HD for a longer period of time than the normal LTI group. FTI (FTI = FTM/ height(2)) was significantly higher in low LTI pts and increased according to BMI. LTI was not influenced by different BMI levels. Albumin and C-reactive protein correlated inversely (r = -0.28). However neither of them was statistically different when considering undernourished and normal LTI pts. Our BCM study was able to show a high prevalence of undernutrition, as expressed by low LTI. In our study, BMI and other common markers, such as albumin, failed to predict malnutrition as determined by BCM.

Vascular accesses for haemodialysis in the upper arm cause greater reduction in the carotid-brachial stiffness than those in the forearm: study of gender differences.

Purpose. To evaluate in chronically haemodialysed patients (CHPs), if: (1) the vascular access (VA) position (upper arm or forearm) is associated with differential changes in upper limb arterial stiffness; (2) differences in arterial stiffness exist between genders associated with the VA; (3) the vascular substitute (VS) of choice, in biomechanical terms, depends on the previous VA location and CHP gender. Methods. 38 CHPs (18 males; VA in upper arm: 18) were studied. Left and right carotid-brachial pulse wave velocity (PWV(c-b)) was measured. In in vitro studies, PWV was obtained in ePTFE prostheses and in several arterial and venous homografts obtained from donors. The biomechanical mismatch (BM) between CHP native vessel (NV) and VS was calculated. Results/Conclusions. PWV(c-b) in upper limbs with VA was lower than in the intact contralateral limbs (P < 0.05), and differences were higher (P < 0.05) when the VA was performed in the upper arm. Differences between PWV(c-b) in upper limbs with VA (in the upper arm) with respect to intact upper limbs were higher (P < 0.05) in males. Independently of the region in which the VA was performed, the homograft that ensured the minimal BM was the brachial artery. The BM was highly dependent on gender and the location in the upper limb in which the VA was performed.

Vascular cryografts offer better biomechanical properties in chronically hemodialyzed patients: role of cryograft type, arterial pathway, and diabetic nephropathy as matching determinants.

This study aimed to characterize the following: (i) in chronically hemodialyzed subjects (CHDSs), with and without diabetic nephropathy (DN), and in healthy subjects (non-CHDSs) different arterial pathways stiffness to determine potential pathology-dependent, etiology- and/or pathway-dependent differences; and (ii) the biomechanical mismatch (BM) between arteries from non-CHDSs or CHDSs (with and without DN) and arterial cryografts, venous cryografts, and synthetic prosthesis to determine arterial pathway, pathology, and/or etiology-related differences in the substitute of election in terms of BM. Carotid-femoral and carotid-brachial pulse wave velocity (PWV) were measured in 30 non-CHDSs and 71 CHDSs (11 with DN). In addition, PWV was measured in arterial (elastic and muscular) and venous cryografts and in expanded polytetrafluorethylene prosthesis. The arterial pathways regional differences and the subjects' arterial pathways-substitutes BM were calculated. Arterial stiffness levels and regional differences were higher in CHDS than in non-CHDS. Among CHDS, those with DN showed higher stiffness in the aorto-femoral pathway and larger regional differences. Cryografts showed always the least BM. Non-CHDS and CHDS differed in the cryograft of election. In CHDS, the BM was related with the cryograft type, arterial pathway, and renal disease etiology. The BM could be minimized, selecting the most adequate cryograft type, taking into account the recipient specific characteristic (i.e., arterial pathway and renal disease etiology).

Vascular access localization determines regional changes in arterial stiffness.

BACKGROUND: Vascular access (VA) dysfunction is a common cause of hospitalization in chronically hemodialyzed patients (CHP) limiting the improvement in health and has been largely studied in order to decrease the morbidity events that involves both the artery and the vein used in the construction of the fistula. In parallel, patients in end-stage renal failure show an increase in arterial stiffness. AIM: The aims of this work were: (a) to evaluate arterial stiffness through pulse wave velocity (PWV) measurements in the carotid-brachial pathway where the arteriovenous fistulae (AVF) was constructed, and (b) to determine possible differences in arterial stiffness between the carotid-brachial pathway with and without VA. METHODS: PWV, clinical and biochemical parameters were measured in 38 CHP. PWV was obtained in the carotid-femoral, and in the left and right carotid-brachial pathway. RESULTS: Carotid-brachial PWV determination in upper limbs with AVF (10.07 +/- ;2.43 m/s) showed significantly lower values than those observed in the contra-lateral arm without VA (11.55 +/- ;2.27 m/s). Curiously, the PWV value observed in arms with an AVF was significantly lower in diabetic than in non-diabetic hemodialyzed patients (NDHP) (8.00 +/- ;2.86 m/s and 10.38 +/- ;2.33 m/s; respectively). Measurements of PWV in the carotid-femoral pathway in CHP showed a mean value of 14.09 +/- ;3.12 m/s. Carotid-femoral PWV in NDHP (14.06 +/- ;2.44 m/s) was significantly lower than that observed in the diabetic patients (16.87 +/- ;3.42 m/s). CONCLUSIONS: Carotid-brachial PWV values obtained in the upper limbs, in which VAs were constructed, were significantly lower than that measured in intact arteries in the contra-lateral pathway in CHP.

Molecular kinetics modeling in hemodialysis: on-line molecular monitoring and spectral analysis.

The knowledge of the underlying molecular kinetics is a key point for the development of a dialysis treatment as well as for patient monitoring. In this work, we propose a kinetic inference method that is general enough to be used on different molecular types measured in the spent dialysate. It estimates the number and significance of the compartments involved in the overall process of dialysis by means of a spectral deconvolution technique, characterizing therefore the kinetic behavior of the patient. The method was applied to 52 patients to reveal the underlying kinetics from dialysate time-concentration profiles of urea, which has a well-known molecular kinetic. Three types of behaviors were found: one-compartmental (exponential decay Tau = 180 +/- 61.64 minutes), bicompartmental (Tau1 = 24.96 +/- 19.33 minutes, Tau2 = 222.32 +/- 76.59 minutes), and tricompartmental (Tau1 = 23.03 +/- 14.21 minutes; Tau2 = 85.75 +/- 27.48 minutes; and Tau3 = 337 +/- 85.52 minutes). In patients with bicompartmental kinetics, the Tau2 was related to the level of dialysis dose. The study concluded that spectral deconvolution technique can be considered a powerful tool for molecular kinetics inference that could be integrated in on-line molecular analysis devices. Furthermore, the method could be used in the analysis of poorly understood molecules as well as in new hemodialysis target biomarkers.

Comparison of standard and artificial neural network estimators of hemodialysis adequacy.

The National Kidney Foundation and the European Renal Association recommend routine measurement of hemodialysis (HD) dose and have set standards for adequacy of treatment. We compare the results of five methods for HD dose estimation, classifying each result as adequate or inadequate on the basis of equilibrated (eq) Urea Reduction Ratio (URR(eq)) > or = 65% or Kt/V(eq) > or = 1.2, to assess the accuracy of each method as a diagnostic tool. Data from 113 patients from two different dialysis units were analyzed. Equilibrated postdialysis blood urea was measured 60 min after each hemodialysis session to calculate URR(eq) and Kt/V(eq), considered as gold standard indexes (GSI). URR and Kt/V were estimated by using the Smye formula, an artificial neural network (ANN), modified URR, the second generation Kt/V Daugirdas formula, and standard indexes based on postdialysis urea, then compared to the GSI. For URR, best estimator was ANN (error rate: ER% = 12.70), followed by modified URR (ER% = 17.46%), the Smye (ER% = 22.22), and standard URR (ER% = 23.81). For Kt/V, the Daugirdas equation and the ANN were similar (ER% = 9.52 and 11.11). The single-pool Kt/V (Kt/V(sp)) > or = 1.4 (ERA recommended) produced an ER% = 7.94 and a false positive rate (FPR%) equal to that shown by the ANN (FPR% = 3.17). According to the current threshold limits for HD dose adequacy, the ANN was a reliable and accurate tool for URR monitoring, better than the Smye and the modified URR methods. The use of the ANN urea estimation yields accurate results when used to calculate Kt/V. The Kt/V(sp) with an adequacy threshold of 1.4 is a superior approach for HD adequacy monitoring, suggesting that the current adequacy limits should be reviewed for both URR and Kt/V.

The role of transfusion-transmitted virus in patients undergoing hemodialysis.

GOALS: To study transfusion-transmitted virus (TTV) infection in 75 patients on hemodialysis and examine its relationship with age, sex, duration of dialysis, history of transfusion, and chronic elevation of alanine aminotransferase (ALT) levels. STUDY: Serum TTV was analyzed by polymerase chain reaction (PCR), TTV genotypes by restriction fragment length polymorphism, and hepatitis C virus (HCV) RNA by PCR. RESULTS: Transfusion-transmitted virus was detected in 32 patients (42.7%). Transfusion-transmitted virus genotypes were as follows: G1 in 16 patients; G2, 3; G3, 1; G4, 2; G2-G5, 6; and unclassified, 4. Mean duration of dialysis was 37 +/- 32 months for TTV-positive patients and 43 +/- 37 months for TTV-negative patients (not significant). Twenty-seven (84%) TTV-positive patients and 27 (63%) TTV-negative patients had a history of transfusions ( p = 0.04). Chronic ALT elevation was observed in 9 patients; 5 of them were TTV-positive (16%) and 4 were TTV-negative (9%) (not significant). Four (40%) HCV RNA-positive patients and 5 (8%) HCV RNA-negative patients had chronic ALT elevation ( p = 0.003). Three TTV-positive patients with chronic ALT elevation were also infected with HCV. The two patients with isolated TTV infection did not have another clinical feature to explain their ALT elevation. CONCLUSIONS: Transfusion-transmitted virus had a high prevalence in the patients on hemodialysis; genotype G1 accounts for half of the cases. Transfusion-transmitted virus infection depends on the transfusional antecedent but not on the duration of dialysis. Chronic ALT elevation is significantly associated with HCV infection but not TTV infection. However, TTV could be a causative agent of chronic ALT elevation in some patients.

Virus de la hepatitis C en pacientes de una unidad de hemodiálisis / Hepatitis C-like viruses in patients in a hemodialysis unit

Nuestro objetivo fue estudiar las características y la variación de la infección por el virus de la hepatitis C (HCV) en los pacientes de una unidad de hemodiálisis durante el período julio 1994-julio 1996. Concluímos que la prevalencia de anti-HCV descendió por el control de la sangre a transfundir y por las medidas de bioseguridad, a expensas de una baja incidencia de nuevos casos. El 80 por ciento de los pacientes eran del genotipo 1a o 1b, se detectó el HCV RNA en casi todos los pacientes anti-HCV positivos pero también en alrededor del 10 por ciento de los anti-HCV positivos tenían signos humorales de cronicidad con hepatitis crónica persistente en los biopsiados y el interferón de un opción terapéutica útil.

Virus de la hepatitis C en pacientes de una unidad de hemodiálisis / Hepatitis C-like viruses in patients in a hemodialysis unit

Nuestro objetivo fue estudiar las características y la variación de la infección por el virus de la hepatitis C (HCV) en los pacientes de una unidad de hemodiálisis durante el período julio 1994-julio 1996. Concluímos que la prevalencia de anti-HCV descendió por el control de la sangre a transfundir y por las medidas de bioseguridad, a expensas de una baja incidencia de nuevos casos. El 80 por ciento de los pacientes eran del genotipo 1a o 1b, se detectó el HCV RNA en casi todos los pacientes anti-HCV positivos pero también en alrededor del 10 por ciento de los anti-HCV positivos tenían signos humorales de cronicidad con hepatitis crónica persistente en los biopsiados y el interferón de un opción terapéutica útil. (AU)