Validation of the SMH Equations for the Estimation of the Total Body Water Volume in Hemodialysis Patients.

Background: Online dialysis clearance monitors typically provide an accurate value for Kt. A value for V (total body water [TBW]) is required to calculate Kt/V, the measure of the adequacy of the delivered dialysis in hemodialysis (HD) patients. Using bioimpedance spectroscopy (BIS), we previously developed 2 sex-specific equations for the estimation of the TBW, which we have chosen to name the St Michael's Hospital (SMH) equations. Objective: The objective of this study was to validate the SMH equations in a second distinct population of patients. Design: Cross-sectional study. Setting: Single center hemodialysis unit at St Michael's Hospital, a tertiary care teaching hospital, in Toronto, Canada. Patients: Eighty-one adult HD patients who had been receiving conventional maintenance HD for at least 3 months. Measurements: Anthropometric measurements including weight, height, and waist circumference were collected. TBW was measured by BIS using the Body Composition Monitor (Fresenius Medical Care, Bad Homburg, Germany). Methods: The Bland-Altman method to calculate the bias and limits of agreement and the difference plot analysis were used to evaluate the difference between the BIS-TBW and the TBW derived from our equations (SMH equation) in this validation cohort. Results: The TBW values based on our equations had a high correlation with BIS-TBW (correlation coefficients = 0.93, P values < .01, bias = 1.8 [95% CI: 1-2.6] liter). Application of SMH equations closely predicted Kt/V, based on BIS value, in all categories of waist circumference. Limitations: Small sample size, single-center, not including peritoneal dialysis patients. A larger and more heterogeneous sample with more patients at the extremes of body mass index would allow for more detailed sub-group analyses in different races and different anthropometric categories to better understand the performance of these equations in discrete sub-groups of patients. Conclusions: In maintenance HD patients, our previously derived equations to estimate the TBW using weight and waist circumference appear to be valid in a distinct patient population. Given the centrality of TBW to the calculation of small molecule clearance, the SMH equations may enhance the measurement of dialysis adequacy and inform practice.

Contexte: En général, les versions en ligne des moniteurs de clairance de la dialyse fournissent une valeur de Kt précise. Une valeur de V (ECT = eau corporelle totale) est nécessaire pour calculer le Kt/V, soit la mesure de l'adéquation de la dialyse chez les patients sous hémodialyse (HD). Grâce à la spectroscopie de bio-impédance (BIS), nous avons précédemment développé deux équations spécifiques au sexe qui permettent d'estimer l'ECT, les « équations du St Michael's Hospital ¼ (équations SMH). Objectif: Valider les équations SMH dans une deuxième population distincte de patients. Conception: Étude transversale. Cadre: L'unité d'hémodialyse du St Michael's Hospital, un hôpital universitaire de soins tertiaires de Toronto (Canada). Sujets: 81 patients adultes suivant des traitements d'HD de maintien conventionnelle depuis au moins 3 mois. Mesures: Des mesures anthropométriques, soit le poids, la taille et le tour de taille, ont été recueillies. L'ECT a été mesurée par BIS (ECT-BIS) à l'aide d'un moniteur de composition corporelle, le Body Composition Monitor TM de Fresenius Medical Care (Bad Homburg, Allemagne). Méthodologie: La méthode Bland-Altman a été utilisée pour calculer le biais et les limites d'agrément. L'analyse des courbes de différence a servi à évaluer la différence entre l'ECT-BIS et l'ECT dérivée de nos équations (équations SMH) dans la cohorte de validation. Résultats: Les valeurs d'ECT obtenues par les équations se sont avérées très étroitement corrélées aux valeurs obtenues par bio-impédance (coefficient de corrélation: 0,93; valeurs de p < 0,01; biais = 1,8 litres [IC 95 %: 1-2,6]). L'application des équations SMH a prédit précisément le Kt/V, sur la base de la valeur par BIS, dans toutes les catégories de tour de taille. Limites: Échantillon de petite taille provenant d'un seul centre et n'incluant pas les patients sous dialyse péritonéale. Un échantillon plus vaste et plus hétérogène, avec davantage de patients dont l'IMC se situe aux extrêmes de la courbe, permettrait une analyse plus détaillée de sous-groupes provenant de différentes ethnies et présentant différentes catégories anthropométriques; ceci permettrait de valider la performance des équations SMH dans des sous-groupes distincts de patients. Conclusion: Dans une population de patients sous HD de maintien, nos équations précédemment dérivées, qui permettent d'estimer l'ECT à partir du poids et du tour de taille, semblent valides. Compte tenu de l'importance de l'ECT dans le calcul de la clairance des petites molécules, les équations SMH pourraient améliorer la mesure de l'adéquation de la dialyse et éclairer la pratique.

Left ventricular strain analysis using cardiac magnetic resonance imaging in patients undergoing in-centre nocturnal haemodialysis.

AIM: Intensified haemodialysis is associated with regression of left ventricular (LV) mass. Compared to LV ejection fraction, LV strain allows more direct assessment of LV function. We sought to assess the impact of in-centre nocturnal haemodialysis (INHD) on global LV strain (radial, circumferential, and longitudinal) and torsion by cardiac MRI (CMR). METHODS: In this prospective, two-centre cohort study, 37 participants on conventional haemodialysis (CHD, 3-4 h/session for three sessions/week) converted to INHD (7-8 h/session for three sessions/week) and 30 participants continued CHD. Participants underwent CMR using a standardized protocol and had biomarker measurements at baseline and 52 weeks. RESULTS: Among the 55 participants (mean age 55; 40% women) with complete CMR data, those who converted to INHD had a significant improvement in their global circumferential strain (GCS, P = 0.025), while those continuing CHD did not have any significant changes in LV strain. When the two groups were compared, there was significant improvement in torsion. LV strains were significantly correlated with each other, but not with troponin I, C-reactive protein, or brain natriuretic protein (NT-proBNP), except for global longitudinal strain (GLS) with troponin I (P = 0.001) and NT-proBNP (P = 0.038). CONCLUSION: Conversion to INHD was associated with significant improvement in GCS over one year of study, although comparisons with the CHD group were not significant. There was also a significant decrease in torsion in the INHD group compared with CHD. Improvement in LV regional function would support the notion that INHD has favourable effects on both LV structure and function.

Extended Duration Nocturnal Hemodialysis and Changes in Plasma Metabolite Profiles.

BACKGROUND AND OBJECTIVES: In-center, extended duration nocturnal hemodialysis has been associated with variable clinical benefits, but the effect of extended duration hemodialysis on many established uremic solutes and other components of the metabolome is unknown. We determined the magnitude of change in metabolite profiles for patients on extended duration nocturnal hemodialysis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: In a 52-week prospective, observational study, we followed 33 patients receiving conventional thrice weekly hemodialysis who converted to nocturnal hemodialysis (7-8 hours per session, three times per week). A separate group of 20 patients who remained on conventional hemodialysis (3-4 hours per session, three times per week) served as a control group. For both groups, we applied liquid chromatography-mass spectrometry-based metabolite profiling on stored plasma samples collected from all participants at baseline and after 1 year. We examined longitudinal changes in 164 metabolites among those who remained on conventional hemodialysis and those who converted to nocturnal hemodialysis using Wilcoxon rank sum tests adjusted for multiple comparisons (false discovery rate <0.05). RESULTS: On average, the nocturnal group had 9.6 hours more dialysis per week than the conventional group. Among 164 metabolites, none changed significantly from baseline to study end in the conventional group. Twenty-nine metabolites changed in the nocturnal group, 21 of which increased from baseline to study end (including all branched-chain amino acids). Eight metabolites decreased after conversion to nocturnal dialysis, including l-carnitine and acetylcarnitine. By contrast, several established uremic retention solutes, including p-cresol sulfate, indoxyl sulfate, and trimethylamine N-oxide, did not change with extended dialysis. CONCLUSIONS: Across a wide array of metabolites examined, extended duration hemodialysis was associated with modest changes in the plasma metabolome, with most differences relating to metabolite increases, despite increased dialysis time. Few metabolites showed reduction with more dialysis, and no change in several established uremic toxins was observed.

Sodium-Reduced Meat and Poultry Products Contain a Significant Amount of Potassium from Food Additives.

BACKGROUND: Sodium-reduced packaged food products are increasingly available to consumers; however, it is not clear whether they are suitable for inclusion in a potassium-reduced diet. For individuals with impaired renal potassium excretion caused by chronic kidney disease and for those taking certain medications that interfere with the rennin-angiotensin aldosterone axis, the need to limit dietary potassium is important in view of the risk for development of hyperkalemia and fatal cardiac arrhythmias. OBJECTIVE: The primary objective of this study was to determine the impact of the reduction of sodium in packaged meat and poultry products (MPPs) on the content of potassium and phosphorus from food additives. DESIGN: This was a cross-sectional study comparing chemically analyzed MPPs (n=38, n=19 original, n=19 sodium-reduced), selected from the top three grocery chains in Canada, based on market share sales. All MPPs with a package label containing a reduced sodium content claim together with their non-sodium-reduced packaged MPP counterparts were selected for analysis. The protein, sodium, phosphorus, and potassium contents of sodium-reduced MPPs and the non-sodium-reduced (original) MPP counterparts were chemically analyzed according to the Association of Analytical Communities official methods 992.15 and 984.27 and compared by using a paired t test. The frequency of phosphorus and potassium additives appearing on the product labels' ingredient lists were compared between groups by using McNemar's test. RESULTS: Sodium-reduced MPPs (n=19) contained 44% more potassium (mg/100 g) than their non-sodium-reduced counterparts (n=19) (mean difference [95% CI): 184 [90-279]; P=0.001). The potassium content of sodium-reduced MPPs varied widely and ranged from 210 to 1,500 mg/100 g. Potassium-containing additives were found on the ingredient list in 63% of the sodium-reduced products and 26% of the non-sodium-reduced products (P=0.02). Sodium-reduced MPPs contained 38% less sodium (mg/100 g) than their non-sodium-reduced counterparts (mean difference [95% CI]: 486 [334-638]; P<0.001). The amounts of phosphorus and protein, as well as the frequency of phosphorus additives appearing on the product label ingredient list, did not significantly differ between the two groups. CONCLUSIONS: Potassium additives are frequently added to sodium-reduced MPPs in amounts that significantly contribute to the potassium load for patients with impaired renal handling of potassium caused by chronic kidney disease and certain medications. Patients requiring potassium restriction should be counseled to be cautious regarding the potassium content of sodium-reduced MPPs and encouraged to make food choices accordingly.

Volume Estimates in Chronic Hemodialysis Patients by the Watson Equation and Bioimpedance Spectroscopy and the Impact on the Kt/Vurea calculation.

BACKGROUND: Accurate assessment of total body water (TBW) is essential for the evaluation of dialysis adequacy (Kt/Vurea). The Watson formula, which is recommended for the calculation of TBW, was derived in healthy volunteers thereby leading to potentially inaccurate TBW estimates in maintenance hemodialysis recipients. Bioimpedance spectroscopy (BIS) may be a robust alternative for the measurement of TBW in hemodialysis recipients. OBJECTIVES: The primary objective of this study was to evaluate the accuracy of Watson formula-derived TBW estimates as compared with TBW measured with BIS. Second, we aimed to identify the anthropometric characteristics that are most likely to generate inaccuracy when using the Watson formula to calculate TBW. Finally, we derived novel anthropometric equations for the more accurate estimation of TBW. DESIGN AND SETTING: This was a cross-sectional study of prevalent in-center HD patients at St Michael's Hospital. PATIENTS: One hundred eighty-four hemodialysis patients (109 men and 75 women) were evaluated in this study. MEASUREMENTS: Anthropometric measurements including weight, height, waist circumference, midarm circumference, and 4-site skinfold (biceps, triceps, subscapular, and suprailiac) thickness were measured; fat mass was measured using the formula by Durnin and Womersley. We measured TBW by BIS using the Body Composition Monitor (Fresenius Medical Care, Bad Homburg, Germany). METHODS: We used the Bland-Altman method to calculate the difference between the TBW derived from the Watson method and the BIS. To derive new equations for TBW estimation, Pearson's correlation coefficients between BIS-TBW (the reference test) and other variables were examined. We used the least squares regression analysis to develop parsimonious equations to predict TBW. RESULTS: TBW values based on the Watson method had a high correlation with BIS-TBW (correlation coefficients = 0.87 and P < .001). Despite the high correlation, the Watson formula overestimated TBW by 5.1 (4.5-5.8) liters and 3.8 (3.0-4.5) liters, in men and women, respectively. Higher fat mass and waist circumference (general and abdominal obesity) were correlated with the greater TBW overestimation by the Watson formula. We created separate equations for men and women based on weight and waist circumference. LIMITATIONS: The main limitation of our study was the lack of an external validation for our novel estimating equation. Furthermore, though BIS has been validated against traditional reference standards, our assumption that it represents the "gold standard" for body compartment assessment may be flawed. CONCLUSIONS: The Watson formula generally overestimates TBW in chronic dialysis recipients, particularly in patients with the highest waist circumference. Widespread reliance on the Watson formula for derivation of TBW may lead to the underestimation of Kt/Vurea..

CONTEXTE: Une évaluation précise du volume d'eau total (VET) de l'organisme est essentielle pour valider l'efficacité de la dialyse (Kt/Vurée). Recommandée pour le calcul du VET, la formule de Watson a pourtant été établie en fonction de volontaires sains. Conséquemment, elle fournit des estimations potentiellement inexactes chez les patients hémodialysés. La spectroscopie de bio-impédance (BIS ­ Bioimpedance Spectroscopy) pourrait s'avérer une alternative fiable pour mesurer le VET des patients hémodialysés. OBJECTIFS DE L'ÉTUDE: Notre principal objectif consistait à comparer l'exactitude des valeurs de VET mesurées par la formule de Watson et par bio-impédance. Secondairement, nous cherchions à cerner les caractéristiques anthropométriques les plus susceptibles d'engendrer des valeurs imprécises avec la formule de Watson. Enfin, nous voulions dériver des équations anthropométriques fiables pour mesurer le VET des patients. TYPE ET CADRE DE L'ÉTUDE: Nous avons mené une étude transversale auprès de patients hémodialysés à l'hôpital St Micheal's de Toronto. PATIENTS: Un total de 184 patients (109 hommes et 75 femmes) ont participé à l'étude. MESURES: Ont été effectuées une série de mesures anthropométriques : poids, grandeur, tour de taille, périmètre brachial et épaisseur de quatre plis cutanés (au biceps, au triceps, sous l'omoplate et au niveau de l'iliaque supérieur). Ces données ont servi à calculer la masse adipeuse avec l'équation de Durnin et Womersley. Pour les mesures du VET par bio-impédance (BIS), on a utilisé un Body Composition Monitor ou BCM (Fresenius Medical Care, à Bad Homburg, en Allemagne). MÉTHODOLOGIE: Nous avons utilisé la méthode de Bland-Altman pour calculer l'écart entre les mesures de VET obtenues par la formule de Watson et par BIS. Pour guider l'élaboration d'équations plus fiables, on a calculé les coefficients de corrélation de Pearson la bio-impédance (test de référence) et d'autres variables. On a développé des équations simplifiées et concises permettant de prédire le VET avec la régression par les moindres carrés. RÉSULTATS: Les valeurs de VET obtenues par la formule de Watson se sont avérées très étroitement corrélées avec les valeurs obtenues par bio-impédance (coefficient de corrélation : 0,87; p<0,001). Toutefois, la formule de Watson a surévalué le VET de 5,1 litres en moyenne (entre 4,5 et 5,8 litres) chez les hommes et de 3,8 litres en moyenne (entre 3,0 et 4,5 litres) chez les femmes. Une masse adipeuse élevée et un fort tour de taille (cas d'obésité générale et d'obésité abdominale) ont été associés aux plus importantes surestimations du VET données par la formule de Watson. Nous avons dérivé des équations distinctes pour les hommes et les femmes en tenant compte du poids du patient et de son tour de taille. LIMITES DE L'ÉTUDE: L'absence de validation externe des nouvelles équations élaborées pour l'estimation du VET constitue la principale limite de notre étude. Par ailleurs, bien que la spectroscopie de bio-impédance ait été validée contre les étalons de référence conventionnels, notre supposition selon laquelle cette méthode représenterait l'étalon par excellence pour mesurer la composition corporelle pourrait être erronée. CONCLUSION: La formule de Watson surestime généralement le VET des patients hémodialysés, particulièrement chez ceux qui présentent un fort tour de taille. Ainsi, le recours généralisé à cette formule pour la dérivation du VET des patients hémodialysés pourrait mener à une sous-évaluation du Kt/Vurée.

Frailty and the Quality of Life in Hemodialysis Patients: The Importance of Waist Circumference.

OBJECTIVE: Frailty among the end-stage renal disease (ESRD) population is highly prevalent and has been associated with mortality. Little is known about the relation of different aspects of body composition, a modifiable risk factor, with the risk of frailty in ESRD population. DESIGN AND METHODS: One hundred and fifty-one patients including 85 men and 66 women, aged ≥18 years with ESRD who had been receiving conventional maintenance hemodialysis (HD) for at least 3 months were included. Body fat and muscle mass from both bioimpedance spectroscopy and skin-fold thickness and waist circumference as a surrogate of abdominal obesity were measured. Frailty was defined based on Fried's criteria. Health-related quality of life was collected using the RAND version of the Kidney Disease Quality of Life (KDQOL-36) Survey. RESULTS: We performed single and multiple predictor logistic regression analyses to determine factors associated with frailty. After adjustment for age, sex, and comorbidities, fat mass (both by bioimpedance spectroscopy and anthropometry) and waist circumference, but not muscle mass remained the main predictors of frailty. The odds ratio of frailty in the third tertile compared with the first was 4.97 (1.70-14.55) and 3.84 (1.39-10.61) for fat mass and waist circumference, respectively (P for trends for both <.05). The scores of physical health and kidney disease effect component of quality of life were lower in frail compared with nonfrail patients (40.7 ± 9.2 vs. 33.7 ± 10.2, P < .01 and 66.8 ± 22.4 vs. 51.6 ± 25.7, P < .05 for physical health and effects of disease, respectively). CONCLUSIONS: Frailty, which is associated with poor outcomes in chronic HD patients, is common and predicted by fat mass and waist circumference but not by body mass index and muscle mass. Interventions to modify abdominal obesity, reflected by waist circumference, could potentially lower the incidence of frailty and hence improve the quality of life in the HD population.

Association between conversion to in-center nocturnal hemodialysis and right ventricular remodeling.

Background: In-center nocturnal hemodialysis (INHD) is associated with favorable left ventricular (LV) remodeling. Although right ventricular (RV) structure and function carry prognostic significance, the impact of dialysis intensification on RV is unknown. Our objectives were to evaluate changes in RV mass index (MI), end-diastolic volume index (EDVI), end-systolic volume index (ESVI) and ejection fraction (EF) after conversion to INHD and their relationship with LV remodeling. Methods: Of 67 conventional hemodialysis (CHD, 4 h/session, three times/week) patients, 30 continued on CHD and 37 converted to INHD (7-8 h/session, three times/week). Cardiac magnetic resonance imaging was performed at baseline and 1 year using a standardized protocol; an experienced and blinded reader performed RV measurements. Results: At 1 year there were significant reductions in RVMI {-2.1 g/m2 [95% confidence interval (CI) -3.8 to - 0.4], P = 0.017}, RVEDVI [-9.5 mL/m2 (95% CI - 16.3 to - 2.6), P = 0.008] and RVESVI [-6.2 mL/m2 (95% CI - 10.9 to - 1.6), P = 0.011] in the INHD group; no significant changes were observed in the CHD group. Between-group comparisons showed significantly greater reduction of RVESVI [-7.9 mL/m2 (95% CI - 14.9 to - 0.9), P = 0.03] in the INHD group, a nonsignificant trend toward greater reduction in RVEDVI and no significant difference in RVMI and RVEF changes. There was significant correlation between LV and RV in terms of changes in mass index (MI) (r = 0.46), EDVI (r = 0.73), ESVI (r = 0.7) and EF (r = 0.38) over 1 year (all P < 0.01). Conclusions: Conversion to INHD was associated with a significant reduction of RVESVI. Temporal changes in RV mass, volume and function paralleled those of LV. Our findings support the need for larger, longer-term studies to confirm favorable RV remodeling and determine its impact on clinical outcomes.

Coincidence of role expectations between staff and volunteer members of drug free community coalitions.

Community coalitions have proliferated as a means of addressing a range of complex community problems. Such coalitions often consist of a small paid staff and volunteer members. The present study examines one likely contributor to coalition effectiveness: the degree of agreement on role expectations between paid staff and volunteer members. Role confusion occurs when paid staff and volunteers differ in their expectations of who is responsible for accomplishing specific tasks. Staff and volunteer members from 69 randomly selected Drug Free Coalitions in the United States as well as 21 Drug Free Coalitions in Connecticut were asked to respond to an online survey asking about 37 specific coalition tasks critical for effective coalition functioning and the degree to which paid staff and/or voluntary members should be responsible for accomplishing each. Our final sample consisted of 476 individuals from 35 coalitions. Using coalitions as the unit of analysis, we found significant differences between paid staff and volunteer coalition members on nine tasks reflecting four domains: meeting leadership and participation, (2) planning and implementation leadership, (3) publicity/media relations, and (4) logistical functions. Implications of these differences and ways that evaluators could help coalitions deal with differing role expectations were discussed.

Nutritional status after conversion from conventional to in-centre nocturnal hemodialysis.

INTRODUCTION: Recipients of conventional hemodialysis (CHD; 3-4 h/session, 3 times/week) experience volume expansion and nutritional impairment which may contribute to high mortality. Prolongation of sessions with in-centre nocturnal hemodialysis (INHD; 7-8 h/session, 3 times/week) may improve clinical outcomes by enhancement of ultrafiltration and uremic toxin removal. MATERIALS AND METHODS: In this prospective cohort study, 56 adult patients who were receiving maintenance CHD for at least 90 days were assigned to CHD (patients who remained in CHD) and INHD (patients who switched to INHD) groups. Both groups were followed for 1 year divided into four 13-week quarters; post-dialysis weight and interdialytic weight gain (IDWG) were captured in each quarter. Repeated measures analysis of variance was used to calculate group main effect, time main effect or time-group interaction effect. RESULTS: Conversion to INHD was associated with a mean (95% confidence interval) change in IDWG of 0.5 (0.08, 1.2) kg as compared to -0.3 (-0.9, 0.1) kg in the CHD group (p < 0.01). In the INHD group, post-dialysis weight (% of baseline pre-dialysis weight) decreased after conversion, reaching a nadir during the first 3 months (0.7%) and subsequently it gradually increased and returned to its baseline at the end of follow-up. A similar temporal trend was seen for serum creatinine but not serum N-terminal pro-brain natriuretic peptide (NT-proBNP) which is a marker of extracellular volume. The changes in serum albumin, prealbumin and hs-CRP were not different between the two groups. CONCLUSIONS: Conversion to INHD was associated with greater IDWG and relatively stable body mass. We speculate that this gain in weight reflects an increase in lean body mass following the change in dialysis modality, which can be concluded from the parallel increase in serum creatinine and the lack of increase in NT-proBNP.

Relationship between changes in blood pressure and left ventricular mass over 1 year in end-stage renal disease.

OBJECTIVE: The optimal timing of blood pressure (BP) measurement is not firmly established for patients undergoing hemodialysis. We sought to assess which BP measurement change best correlates with changes in left ventricular mass index (LVMI) over 1 year in patients with end-stage renal disease. METHODS: Fifty-seven patients were included in a prospective cohort study comparing the cardiovascular impact of conversion to in-center nocturnal hemodialysis versus continuing conventional hemodialysis. BP measurements were recorded at different time points (predialysis, after initiation of dialysis, at the intradialytic nadir, and postdialysis) during dialysis sessions over 12 weeks at baseline and after 1-year follow-up. LVMI was independently measured by a single blinded reader using cardiac magnetic resonance imaging at baseline and 1 year. RESULTS: Overall, the mean LVMI was 69.9 g/m (standard deviation 15.9) at baseline and 69.6 g/m (standard deviation 16.0) at 1 year. The change in initiation mean arterial pressure (MAP) most strongly correlated with the change in LVMI (Pearson correlation coefficient r = 0.71, P < 0.001). The relationship was similar in both dialysis groups and in multivariable analysis. In pairwise comparisons, initiation MAP was more strongly correlated with the change in LVMI than nadir and postdialysis measurements (all P < 0.05). However, the correlation was not stronger than predialysis SBP (P = 0.33). CONCLUSION: The change in initiation MAP correlated best with the change in LVMI over 1 year in patients undergoing hemodialysis. Further studies are needed to determine whether it represents a potentially useful treatment target to prevent adverse ventricular remodeling, thereby improving cardiovascular outcome.ClinicalTrials.gov Identifier: NCT00718848.

Relationships Between Left Ventricular Structure and Function According to Cardiac MRI and Cardiac Biomarkers in End-Stage Renal Disease.

BACKGROUND: We sought to assess the relationships between left ventricular (LV) remodelling and the mechanical and uremic stressors in hemodialysis patients. METHODS: In this prospective 2-centre cohort study, 67 prevalent hemodialysis patients were followed for 1 year. Data on routine bloodwork and predialysis blood pressure (BP) measurements were collected over a 12-week period. LV end-diastolic volume (LVEDV) and LV mass (LVM) were measured using cardiac magnetic resonance imaging and indexed. High-sensitivity troponin-I (hsTnI), N-terminal pro-brain natriuretic peptide (NT-proBNP), fibroblast growth factor 23 (FGF-23), and high-sensitivity C-reactive protein (hsCRP) were also measured. All study procedures were performed at baseline and at 1 year. We examined the relationships between LV remodelling and (1) NT-proBNP and hsTnI (LV stretch and injury); (2) ultrafiltration volume (UFV) and interdialytic weight gain (IDWT; volume overload); (3) predialysis BP measurements (pressure overload); and (4) biomarkers of inflammation (hsCRP) and fibrosis (FGF-23). RESULTS: LVEDV was significantly associated with UFV and with IDWT, at baseline as well as at 1 year. NT-proBNP was significantly and negatively correlated with UFV and IDWT, respectively, at 1 year. There were significant correlations between systolic BP and LVM index, at baseline and at 1 year as well as longitudinally. Systolic BP was the only parameter longitudinally correlated with LVM/LVEDV. hsTnI was not associated with urea, parathyroid hormone, calcium, phosphorus, FGF-23, hsCRP, or hemoglobin. CONCLUSIONS: We did not observe significant relationships between myocardial injury and markers of fibrosis, inflammation, and LV remodelling. Elevated predialysis systolic BP, which might represent a common mediator of pressure and volume overload, appears to be a dominant stimulus for LV remodelling.

A case report of unusually long lag time between immunotactoid glomerulopathy (itg) diagnosis and diffuse large B-cell lymphoma (DLBCL) development.

BACKGROUND: Immunotactoid glomerulopathy (ITG) is a rare cause of proteinuria characterized by organized microtubular deposits in the glomerulus. ITG has been associated with underlying lymphoproliferative disorders and any renal impairment may be reversible with treatment of the concomitant hematologic malignancy. This case is the first reported in literature where diffuse large B cell lymphoma developed two years following the initial ITG diagnosis. CASE PRESENTATION: A 55-year-old woman with a history of well-controlled diabetes mellitus and thalassemia trait presented with proteinuria (830 mg/day) in 2010. Initially, she was managed with renin-angiotensin-aldosterone-system blockade. In 2012, the proteinuria worsened (4.3 g/day) and a renal biopsy showed immunotactoid glomerulopathy (Fig. 1). Despite extensive work up, no lymphoproliferative disorder was initially found. In January 2014, the patient presented with a soft-palate mass found on biopsy to be diffuse large B-cell lymphoma. She received 6 cycles of R-CHOP, 4 cycles of high dose methotrexate chemotherapy for CNS prophylaxis and 30 Gy of Intensity Modulated Radiation Therapy. Follow-up revealed complete remission of diffuse large B-cell lymphoma and resolution of proteinuria from the ITG. CONCLUSION: As we recognize that patients with ITG may develop hematopoietic neoplasms, close long-term monitoring is important. Moreover, treatment of the lymphoproliferative disorder can allow for complete remission of ITG.

Reduction of carbamylated albumin by extended hemodialysis.

Introduction Among conventional hemodialysis (CHD) patients, carbamylated serum albumin (C-Alb) correlates with urea and amino acid deficiencies and is associated with mortality. We postulated that reduction of C-Alb by intensive HD may correlate with improvements in protein metabolism and cardiac function. Methods One-year observational study of in-center nocturnal extended hemodialysis (EHD) patients and CHD control subjects. Thirty-three patients receiving 4-hour CHD who converted to 8-hour EHD were enrolled, along with 20 controls on CHD. Serum C-Alb, biochemistries, and cardiac MRI parameters were measured before and after 12 months of EHD. Findings EHD was associated with reduction of C-Alb (average EHD change -3.20 mmol/mol [95% CI -4.23, -2.17] compared to +0.21 [95% CI -1.11, 1.54] change in CHD controls, P < 0.001). EHD was also associated with increases in average essential amino acids (in standardized units) compared to CHD (+0.38 [0.08, 0.68 95%CI]) vs. -0.12 [-0.50, 0.27, 95% CI], P = 0.047). Subjects who reduced C-Alb more than 25% were found to have reduced left ventricular mass, increased urea reduction ratio, and increased serum albumin compared to nonresponders, and % change in C-Alb significantly correlated with % change in left ventricular mass. Discussion EHD was associated with reduction of C-Alb as compared to CHD, and reduction of C-Alb by EHD correlates with reduction of urea. Additional studies are needed to test whether reduction of C-Alb by EHD also correlates with improved clinical outcomes.

The Association Between Conversion to In-centre Nocturnal Hemodialysis and Left Ventricular Mass Regression in Patients With End-Stage Renal Disease.

BACKGROUND: In-centre nocturnal hemodialysis (INHD, 7-8 hours/session, 3 times/week) is an increasingly utilized form of dialysis intensification, though data on the cardiovascular benefits of this modality are limited. METHODS: In this prospective cohort study, we enrolled 67 prevalent conventional hemodialysis (CHD, 4 hours/session, 3 times/week) recipients at 2 medical centres in Canada, of whom 37 converted to INHD and 30 remained on CHD. The primary outcome was the change in left ventricular mass (LVM) after 1 year as assessed by cardiac magnetic resonance imaging. Secondary outcomes included changes in serum phosphate concentration, phosphate binder burden, haemoglobin, erythropoiesis stimulating agent usage, and blood pressure. RESULTS: Conversion to INHD was associated with a 14.2 (95% confidence interval [CI] 1.2-27.2) g reduction in LVM as compared with continuation on CHD. This result was maintained after adjustment for baseline imbalances between the groups and in ancillary analyses. There was a trend toward a larger drop in systolic blood pressure (9.8 [95% CI, -1.4-20.9] mm Hg) among INHD recipients with a significant reduction in the number of prescribed antihypertensive agents (0.7 [95% CI, 0.3-1.1] agents). Serum phosphate declined by 0.40 (95% CI, 0.16-0.63) mmol/L among INHD recipients without any difference in calcium-based phosphate binder requirements, as compared with those who remained on CHD. CONCLUSIONS: Compared with continuation of CHD, conversion to INHD was associated with significant LVM regression and reduction in serum phosphate concentration at 1 year.

Relationship between different blood pressure measurements and left ventricular mass by cardiac magnetic resonance imaging in end-stage renal disease.

Hypertension is prevalent in patients with end-stage renal disease and is strongly associated with left ventricular hypertrophy (LVH), an independent predictor of cardiovascular mortality. Blood pressure (BP) monitoring in hemodialysis patients may be unreliable because of its lability and variability. We compared different methods of BP measurement and their relationship with LVH on cardiac magnetic resonance imaging. Sixty patients undergoing chronic hemodialysis at a single dialysis center had BP recorded at each dialysis session over 12 weeks: pre-dialysis, initial dialysis, nadir during dialysis, and post-dialysis. Forty-five of these patients also underwent 44-hour inter-dialytic ambulatory BP monitoring. Left ventricular mass index (LVMI) was measured using cardiac magnetic resonance imaging and the presence of LVH was ascertained. Receiver operator characteristic curves were generated for each BP measurement for predicting LVH. The mean LVMI was 68 g/m(2) (SD = 15 g/m(2)); 13/60 patients (22%) had LVH. Mean arterial pressure measured shortly after initiation of dialysis session was most strongly correlated with LVMI (Pearson correlation coefficient r = 0.59, P < .0001). LVH was best predicted by post-dialysis systolic BP (area under the curve, 0.83; 95% confidence interval, 0.72-0.94) and initial dialysis systolic BP (area under the curve, 0.81; 95% confidence interval, 0.70-0.92). Forty-four-hour ambulatory BP and BP variability did not significantly predict LVH. Initial dialysis mean arterial pressure and systolic BP and post-dialysis systolic BP are the strongest predictors of LVH, and may represent the potentially best treatment targets in hemodialysis patients to prevent end-organ damage. Further studies are needed to confirm whether treatment targeting these BP measurements can optimize cardiovascular outcomes.

Correlates of left ventricular mass in chronic hemodialysis recipients.

We aimed to clarify the correlates of left ventricular mass and secondarily, left ventricular volume, in a cohort of prevalent hemodialysis recipients. Left ventricular hypertrophy is common and left ventricular mass is a widely-accepted surrogate for clinical outcomes in dialysis recipients, who are often subjected to chronic pressure and volume overload. However, the precise pathophysiologic mechanisms of left ventricular hypertrophy in this unique population have not been well understood. This was a cross-sectional study of patients receiving conventional thrice-weekly dialysis in Toronto, Canada. Left ventricular mass and volume were assessed with cardiac magnetic resonance and indexed to the patient's height to the power of 2.7. Fibroblast growth factor-23 concentration was measured using a C-terminal enzyme-linked immunosorbent assay. Patient demographics, comorbidities, dialysis-associated blood pressures and ultrafiltration volumes, biochemical and hematologic parameters, vascular access and medications were extracted from clinical records. Multivariable linear regression was used to identify independent correlates of left ventricular mass index (LVMI) and the left ventricular end diastolic volume index (LVEDVI). We enrolled 56 patients, of whom 23 (41.1 %) were women with mean age 54 ± 12 years. Mean LVMI was 31.1 ± 6.8 g/m(2.7). In multivariable analyses, systolic blood pressure and LVEDVI were the only factors significantly associated with LVMI. Post-dialysis weight, percent reduction in urea and the presence of a permanent form of vascular access were associated with LVEDVI. Fibroblast growth factor-23 was not associated with either LVMI or LVEDVI. Blood pressure and left ventricular dilatation are independent determinants of elevated left ventricular mass. Aggressive blood pressure reduction and avoidance of volume overload may confer LVM regression and improve clinical outcomes.

Supercath Safety Clampcath buttonhole creation: complication of catheter breakage.

The creation of buttonhole tracks with Supercath Safety Clampcath is a novel and simple technique that allows dull fistula needle insertions with relative ease and diminished pain. As greater experience with this procedure develops, new issues arise for consideration. We report an unexpected complication of Supercath Safety Clampcath catheter breakage that may be due to physical distortions as a result of its location in the antecubital fossa just proximal to the elbow joint. We present a review of our experience and a framework for the safe ongoing use of this device for creation of buttonholes in fistula for hemodialysis.

Comparative assessment of 2-dimensional echocardiography vs cardiac magnetic resonance imaging in measuring left ventricular mass in patients with and without end-stage renal disease.

BACKGROUND: While echocardiography (ECHO)-measured left ventricular mass (LVM) predicts adverse cardiovascular events that are common in hemodialysis (HD) recipients, cardiac magnetic resonance imaging (CMR) is now considered the reference standard for determination of LVM. This study aimed to evaluate concordance between LVM measurements across ECHO and CMR among chronic HD recipients and matched controls. METHODS: A single-centre, cross-sectional study of 41 chronic HD patients and 41 matched controls with normal kidney function was performed to compare LVM measurements and left ventricular hypertrophy (LVH) designation by ECHO and CMR. RESULTS: In both groups, ECHO, compared with CMR, overestimated LVM. Bland-Altman analysis demonstrated wider agreement limits in LVM measurements by ECHO and CMR in the chronic HD group (mean difference, 60.8 g; limits -23 g to 144.6 g) than in the group with normal renal function (mean difference, 51.4 g; limits -10.5 g to 113.3 g). LVH prevalence by ECHO and CMR in the chronic HD group was 37.5% and 22.5%, respectively, while 17.5% and 12.5% had LVH by ECHO and CMR, respectively, in the normal kidney function group. Intermodality agreement in the designation of LVH was modest in the chronic HD patients (κ = 0.42, P = 0.005) but strong (κ = 0.81, P < 0.001) in the patients with preserved kidney function. Agreement was strong in assessing LVH by ECHO and CMR only in those with normal kidney function. CONCLUSIONS: Our results suggest that the limitations of LVM measurement by ECHO may be more pronounced in patients receiving HD, and provide additional support for the use of CMR in research and clinical practice when rigourous assessment of LVM is essential.