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We reviewed a number of prospective randomized and multiple retrospective cohort studies of different dialysis prescriptions: longer dialysis time, at a frequency of at least three times a week, or a frequency of daily hemodialysis with a shorter dialysis time. Interestingly, the retrospective analyses have generally found significant survival benefits in the intensive dialysis groups, whereas more modest effects were observed in the prospective randomized controlled trials. The reason for this discrepancy may be related to the retrospective nature of the studies and possible selection bias; for example, the patients who were prescribed more frequent dialysis may have had more difficulties with volume control or high blood pressure. In contrast, the randomized controlled trials of increased dialysis frequency, which have shown indirect and modest benefits in complex coprimary end points, have small sample sizes and are plagued with difficulties in recruitment and compliance with the randomly allocated more frequent dialysis. This review, which attempts to balance the potential benefits of more frequent dialysis with the burden on the patient's lifestyle, an increased risk of access malfunction, as well as societal costs of such intensive dialysis prescriptions, concludes in favor of the conventional three times per week dialysis (at a minimum) but at longer dialysis times than is currently prescribed based on the Kt/Vurea metric alone. [ABSTRACT FROM AUTHOR]

Eighty-two percent (82%) of patients initiating hemodialysis in the United States in 2006 did so with a catheter as the functioning access. Even in patients who have been followed by nephrologists for 6 months or more, 74% of patients initiated dialysis with a catheter. This is a multifactoral problem that requires attention and solutions from all stakeholders, including the nephrologist, the vascular surgeon, the hospital, and the insurance industry, as well as the patient and family. We propose a series of specific proposals that include a process for the timely referral and timely placement of a permanent access based on the patient's estimated or measured glomerular filtration rate (GFR), and a ‘pay-for-performance’ measure for vascular surgeons and nephrologists who admit patients with functional permanent accesses; such pay for performance would place a higher value for patients who are admitted with a functional arteriovenous (AV) fistula than for patients who are admitted with an AV graft. We also propose that hospitals develop a less permissive process for placement of PICC (peripherally inserted central catheters) lines in patients with GFR <60 ml/min and to consider surgery for access placement as ‘urgent’. Finally, a more proactive educational process for patients and their families, including an ‘informed non-consent’ for patients who defer placement of a permanent access needs to be considered. The morbidity, mortality, and health-care costs associated with prolonged catheter use mandate urgent attention to this problem. [ABSTRACT FROM AUTHOR]

Hemodialysis access failure: A call to action. Recent evidence suggests that the cost as well as the morbidity associated with the maintenance of hemodialysis access is increasing rapidly; currently, the cost exceeds 1 billion dollars and access related hospitalization accounts for 25% of all hospital admissions in the U.S.A. This increase in cost and morbidity has been associated with several epidemiological trends that may contribute to access failure. These include late patient referral to nephrologists and surgeons, late planning of vascular access as well as a shift from A-V fistulaes to PTFE grafts and temporary catheters, which have a higher failure rate. The reasons for this shift in the types of access is multifactorial and is not explained by changes in the co-morbidities of patients presenting to dialysis. Surgical preference and training also appear to play an important role in the large regional variation and patency rate of these PTFE grafts. We propose a program for early placement of A-V fistulae, a continuous quality improvement, multidisciplinary program to monitor access outcome, the development of new biomaterials, and a research plan to investigate pharmacological intervention to reduce development of stenosis and clinical interventions to treat those that do develop, prior to thrombosis. [ABSTRACT FROM AUTHOR]

Editorial. Comments on the study by Fleischman and colleagues which showed that low body mass index (BMI) is associated with increased risk of hospitalization and mortality, even after adjusting for demographic attributes and nutritionally-associated serum markers. Additional protective effect of having 'excess' nutrition, particularly in the Afro-American patient; Hemodialysis nutrition; ESRD.

Uremic malnutrition is a predictor of death independent of inflammatory status.Background.Several studies have pointed out the influence of nutritional parameters and/or indices of inflammation on morbidity and mortality. Often, these conditions coexist, and the relative importance of poor nutritional status and chronic inflammation in terms of predicting clinical outcomes in chronic hemodialysis (CHD) patients has not been clarified.Methods.We undertook a prospective cohort study analyzing time-dependent changes in several established nutritional and inflammatory markers, and their influence on mortality in 194 CHD patients (53% male, 36% white, 30% with diabetes mellitus, mean age 55.7± 15.4 years) throughout a 57-month period. Serial measurements of serum concentrations of albumin, prealbumin, creatinine, transferrin, cholesterol, and C-reactive protein (CRP), as well as normalized protein catabolic rate, postdialysis weight, and phase angle and reactance by bioelectrical impedance analysis were performed every 3 months. Clinical outcomes were simultaneously assessed using indicators of mortality.Results.Serum albumin, serum prealbumin, serum creatinine, and phase angle were significant predictors of all-cause mortality, even after adjustment for serum CRP concentrations. Serum CRP concentrations were not significantly associated with mortality. Serum albumin concentrations and phase angle were also independent predictors of cardiovascular deaths in the multivariate model.Conclusion.The nutritional status of CHD patients predicts mortality independent of concomitant presence or absence of inflammatory response. Prevention of, and timely intervention to treat uremic malnutrition by suitable means are necessary independent of the presence and/or therapy of inflammation in terms of improving clinical outcomes in CHD patients. [ABSTRACT FROM AUTHOR]

Urea volume of distribution exceeds total body water in patients with acute renal failure.. Background: An accurate estimate of volume of distribution of urea (V[sub urea]) is critically important to guide the prescription of therapy and the quantification of delivered dialysis dose in patients with chronic and acute renal failure (ARF). While V[sub urea] has been shown to be substantially the same as total body water (TBW) in other patient populations, this relationship has not been adequately studied in detail in ARF patients. Methods: To evaluate this question, we undertook a systematic study of these parameters in a cohort of 28 patients with ARF to analyze methods of estimating V[sub urea] and TBW using blood-based kinetic data, anthropometric data and bioelectrical impedance analysis (BIA). Results: The results show that V[sub urea] estimated by double-pool Kt/V (67.9 ± 19.2 L) and by equilibrated Kt/V (61.2 ± 13.6 L) were statistically significantly higher than V[sub urea] determined by single-pool Kt/V (55.3 ± 12.9 L; difference of 16% and 11%, respectively). Determination of TBW by anthropometric measurements (Watson, 42.5 ± 7.0 L; Hume-Weyer, 43.6 ± 7.1 L; Chertow, 46.8 ± 8.1 L) yielded significantly lower measures compared to TBW determined by physiological formulae and by BIA (51.1 ± 11.6 L and 51.1 ± 13.3 L, respectively). Most importantly, all measures of V[sub urea] by blood-based kinetics exceeded TBW measurements by any method (7% to 50% difference). Conclusion: Our results suggest that in terms of useful guidelines to prescribe a specific dose of dialysis in patients with acute renal failure, estimates of TBW cannot be used as a surrogate for V[sub urea] in determining dialysis adequacy. [ABSTRACT FROM AUTHOR]

Mortality rates for maintenance hemodialysis patients are much higher than the general population and are even greater soon after starting dialysis. Here we analyzed mortality patterns in 86,886 patients in 11 countries focusing on the early dialysis period using data from the Dialysis Outcomes and Practice Patterns Study, a prospective cohort study of in-center hemodialysis. The primary outcome was all-cause mortality, using time-dependent Cox regression, stratified by study phase adjusted for age, sex, race, and diabetes. The main predictor was time since dialysis start as divided into early (up to 120 days), intermediate (121-365 days), and late (over 365 days) periods. Mortality rates (deaths/100 patient-years) were 26.7 (95% confidence intervals 25.6-27.9), 16.9 (16.2-17.6), and 13.7 (13.5-14.0) in the early, intermediate, and late periods, respectively. In each country, mortality was higher in the early compared to the intermediate period, with a range of adjusted mortality ratios from 3.10 (2.22-4.32) in Japan to 1.15 (0.87-1.53) in the United Kingdom. Adjusted mortality rates were similar for intermediate and late periods. The ratio of elevated mortality rates in the early to the intermediate period increased with age. Within each period, mortality was higher in the United States than in most other countries. Thus, internationally, the early hemodialysis period is a high-risk time for all countries studied, with substantial differences in mortality between countries. Efforts to improve outcomes should focus on the transition period and the first few months of dialysis. [ABSTRACT FROM AUTHOR]

To compare the relative effectiveness of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) in reducing cardiovascular mortality in chronic hemodialysis patients, we conducted an observational analysis of all patients initiated on ACEI or ARB therapy undergoing chronic hemodialysis at a large dialysis provider. Survival curves with mortality hazard ratios (HRs) were generated using the Kaplan-Meier method and Cox regression. Outcomes were compared using inverse probability of treatment weighting and propensity score matching. Over 6 years, 22,800 patients were newly initiated on an ACEI and 5828 on an ARB after at least 60 days of chronic hemodialysis. After adjustment for baseline cardiovascular risk factors, there was no significant difference in the risk of cardiovascular, all-cause, or cerebrovascular mortality in patients initiated on an ARB compared with an ACEI (HR of 0.96). A third of 28,628 patients, newly started on an ACEI or ARB, went on to another antihypertensive medication in succession. After adjustment for risk factors, 701 patients initiated on combined ACEI and ARB therapy (HR of 1.45) or 6866 patients on ACEI and non-ARB antihypertensive agent (HR of 1.27) were at increased risk of cardiovascular death compared with 1758 patients initiated on an ARB and non-ACEI antihypertensive therapy. Thus, an ARB, in combination with another antihypertensive medication (but not an ACEI), may have a beneficial effect on cardiovascular mortality. As observational studies may be confounded by indication, even when adjusted, randomized clinical trials are needed to confirm these findings. [ABSTRACT FROM AUTHOR]

Dialysis patients have a greater number of hospitalization events compared to patients without renal failure. Here we studied the relationship between different post-discharge interventions and repeat hospitalization in over 126,000 prevalent hemodialysis patients to explore outpatient strategies that minimize the risk of repeat hospitalization. The primary outcome was repeat hospitalization within 30 days of discharge. Compared to pre-hospitalization values, the levels of hemoglobin, albumin, phosphorus, calcium, and parathyroid hormone and weight were significantly decreased after hospitalization. Using covariate-adjusted models, those patients whose hemoglobin was monitored within the first 7 days after discharge, followed by modification of their erythropoietin dose had a significantly reduced risk for repeat-hospitalization when compared to the patients whose hemoglobin was not checked, nor was the dose of erythropoietin changed. Similarly, administration of vitamin D within the 7 days following discharge was significantly associated with reduced repeat hospitalization when compared to patients on no vitamin D. Therefore, it appears that immediate re-evaluation of anemia management orders and resumption of vitamin D soon after discharge may be an effective way to reduce repeat hospitalization.Kidney International (2009) 76, 331–341; doi:10.1038/ki.2009.199; published online 10 June 2009 [ABSTRACT FROM AUTHOR]

Urea space and total body water measurements by stable isotopes in patients with acute renal failure. Background. Knowledge of urea volume of distribution (Vurea) in patients with acute renal failure (ARF) is critical in order to prescribe and monitor appropriate dialytic treatment. We have recently shown that in ARF patients, Vurea estimation by urea kinetic modeling is significantly higher than total body water (TBW) by anthropometric estimation. However, these estimates of Vurea and TBW have not been validated by isotopic methods, considered as reference measurement standards. Methods. In this study, we measured Vurea by [13C]urea and TBW by deuterium oxide (D2O) in 21 patients with ARF (14 males, 7 females, age 62.0 ± 10.6 years old, 83% Caucasian, 17% African American) at three different centers. These measurements were compared to TBW estimates from anthropometric and bioelectrical impedance (BIA) measurements. Results. Our results show that Vurea by [13C]urea (51.0 ± 11.7 L) is significantly higher than TBW estimated by all other methods (TBW by D2O: 38.3 ± 9.8 L, P < 0.001; TBW by BIA: 45.7 ± 15.7 L, P= 0.08; TBW by Watson formula: 38.3 ± 7.3 L, P < 0.001; TBW by Chertow formula: 39.3 ± 7.8 L, P= 0.002, all versus Vurea). Despite significant overestimation of the absolute value and considerable variation, Vurea significantly correlated with TBW by BIA ( r= 0.66, P < 0.01) and TBW by D2O ( r= 0.5, P= 0.04). There was also significant correlation between D2O and BIA determined TBW ( r= 0.8, P < 0.001). Conclusion. In terms of useful guidelines to prescribe a specific dose of dialysis in patients with ARF, conventional estimates of TBW as surrogates for Vurea should be used with caution. We propose that these conventional estimates of TBW should be increased by approximately 20% (a factor of 1.2) to avoid significant underdialysis. [ABSTRACT FROM AUTHOR]

Cardiovascular disease is the leading cause of mortality in uremic patients. In large cross-sectional studies of dialysis patients, traditional cardiovascular risk factors such as hypertension and hypercholesterolemia have been found to have low predictive power, while markers of inflammation and malnutrition are highly correlated with cardiovascular mortality. However, the pathophysiology of the disease process that links uremia, inflammation, and malnutrition with increased cardiovascular complications is not well understood. We hereby propose the hypothesis that increased oxidative stress and its sequalae is a major contributor to increased atherosclerosis and cardiovascular morbidity and mortality found in uremia. This hypothesis is based on studies that conclusively demonstrate an increased oxidative burden in uremic patients, before and particularly after renal replacement therapies, as evidenced by higher concentrations of multiple biomarkers of oxidative stress. This hypothesis also provides a framework to explain the link that activated phagocytes provide between oxidative stress and inflammation (from infectious and non-infectious causes) and the synergistic role that malnutrition (as reflected by low concentrations of albumin and/or antioxidants) contributes to the increased burden of cardiovascular disease in uremia. We further propose that retained uremic solutes such as beta-2 microglobulin, advanced glycosylated end products (AGE), cysteine, and homocysteine, which are substrates for oxidative injury, further contribute to the pro-atherogenic milieu of uremia. Dialytic therapy, which acts to reduce the concentration of oxidized substrates, improves the redox balance. However, processes related to dialytic therapy, such as the prolonged use of catheters for vascular access and the use of bioincompatible dialysis membranes, can contribute to a pro-inflammatory and pro-oxidative state and thus to a pro-atherogenic state. Anti-oxidative therapeutic... [ABSTRACT FROM AUTHOR]

Inflammatory signals associated with hemodialysis. Background. Inflammation is highly prevalent in chronic hemodialysis patients. Because hemodialysis involves the contact of blood with “foreign” surfaces, and the documented activation of several humoral and cellular pathways during the procedure, the hemodialysis procedure has been suggested as a potential source of inflammation in this patient population. Earlier studies did not provide clear-cut evidence of the potential contribution of the hemodialysis procedure to inflammation, as assessed by markers of inflammation such as cytokine levels and acute-phase protein production. Methods. Nine patients were studied using primed-constant infusion of l-(l-13 C) leucine 2 hours before, during, and 2 hours after a single hemodialysis session. We evaluated the effects of hemodialysis on induction of interleukin-6 (IL-6) production as well as the fractional synthetic rates (FSR) of albumin and fibrinogen, two well-known acute-phase proteins. Results. During hemodialysis, albumin FSR and fibrinogen FSR increased significantly compared to the measurements obtained during baseline period. During this period, albumin and fibrinogen FSR increased 64% and 34%, respectively, compared to baseline (P < 0.05). While the increase in IL-6 concentration was modest during hemodialysis (14%), the levels further increased at the end of the 2-hour post-hemodialysis period (68% higher compared to baseline, P < 0.05). Fibrinogen FSR also demonstrated a further increase during the post-dialysis period (17% higher compared to the intradialytic period and 58% higher compared to baseline), while albumin FSR stabilized during this period. Conclusions. The results provide clear evidence of hemodialysis-induced inflammatory response. The process is most notable during the 2-hour post-hemodialysis period. [ABSTRACT FROM AUTHOR]

Therapeutic effects of oral nutritional supplementation during hemodialysis. Background. Protein-calorie malnutrition is common in chronic hemodialysis (CHD) patients and correlates with morbidity and mortality in these patients. There are limited trials evaluating the efficacy of oral nutritional supplementation in malnourished CHD patients. Methods. Eighty-five CHD patients with evidence of malnutrition were included in this prospective study. Patients were followed for a 3-month baseline period during which they received conventional nutrition counseling. This was followed by an intervention period, during which an oral nutritional supplement specifically formulated for CHD patients was given over a period of 6 months. An important element of this study was that the nutritional supplement was provided during dialysis to ensure compliance. Serial measurements of nutritional parameters including concentrations of serum albumin, prealbumin, transferrin as well as body mass index (BMI) and subjective global assessment (SGA) were obtained during the 9-month period. Results. The nutritional parameters did not change during the 3-month baseline period. Following administration of oral supplementation during hemodialysis, there were significant increases in concentrations of serum albumin (from 3.33 ± 0.32 g/dL at baseline, to 3.65 ± 0.26 g/dL at month 6, P < 0.0001) and serum prealbumin (from 26.1 ± 8.6 mg/dL at baseline, to 30.7 ± 7.4 mg/dL at month 6, P = 0.002). Mean SGA score increased 14% by the end of the study (P = 0.023). Although BMI and estimated dry weight increased also, these changes were not statistically significant. Serum transferrin did not change during the study period. Conclusion. Oral nutritional supplementation given during hemodialysis improves nutritional markers in malnourished CHD patients. [ABSTRACT FROM AUTHOR]

Vascular access blood flow monitoring reduces access morbidity and costs. Background. Vascular access morbidity results in suboptimal patient outcomes and costs more than $8000 per patient-year at risk, representing approximately 15% of total Medicare expenditures for ESRD patients annually. In recent years, the rate of access thrombosis has improved following the advent of vascular access blood flow monitoring (VABFM) programs to identify and treat stenosis prior to thrombosis. To define further both the clinical and financial impact of such programs, we used the ultrasound dilution method to study the effects of VABFM on thrombosis-related morbid events and associated costs, compared with both dynamic venous pressure monitoring (DVPM) and no monitoring (NM) in arteriovenous fistulas (AVF) and grafts. Methods. A total of 132 chronic hemodialysis patients were followed prospectively for three consecutive study phases (I, 11 months of NM; II, 12 months of DVPM; III, 10 months of VABFM). All vascular access-related information (thrombosis rate, hospitalization, angiogram, angioplasty, access surgery, thrombectomy, catheter placement, missed treatments) was collected during the three study periods. Results. During the three study phases, graft thrombosis rate was reduced from 0.71 (phase I), to 0.67 (phase II), to 0.16 (phase III) events per patient-year at risk (P < 0.001 phase III vs. phases I and II). Similarly, hospital days, missed treatments, and catheter use related to thrombotic events were significantly reduced during phase III compared to phases I and II. Hospital days related to vascular access morbidity and adjusted for patient-year at risk were 1.8, 1.6, and 0.4 and missed dialysis treatments were 0.98, 0.86, and 0.26 treatments per patient-year at risk for phases I, II, and III, respectively (P < 0.001 for phase III vs. phases I and II). Catheter use was also significantly reduced during phases II and III, from 0.29 (phase I) to 0.17 and further to... [ABSTRACT FROM AUTHOR]

Investigates the role of transforming growth factor-beta in the pathogenesis of dialysis-related to amyloidosis. Termination of inflammatory response; Release of proinflammatory cytokines through macrophage activation; Measurement of endotoxin levels.

Association of morbidity with markers of nutrition and inflammation in chronic hemodialysis patients: A prospective study. Background. Numerous studies suggest a strong association between nutrition and clinical outcome in chronic hemodialysis (CHD) patients. Nevertheless, the pathophysiological link between malnutrition and morbidity remains to be clarified. In addition, recent evidence suggests that nutritional indices may reflect an inflammatory response, as well as protein–calorie malnutrition. In this study, we prospectively assessed the relative importance of markers of nutritional status and inflammatory response as determinants of hospitalization in CHD patients. Methods. The study consisted of serial measurements of concentrations of serum albumin, creatinine, transferrin, prealbumin, C-reactive protein (CRP), and reactance values by bioelectrical impedance analysis (BIA) as an indirect measure of lean body mass every 3 months over a period of 15 months in 73 CHD patients. Outcome was determined by hospitalizations over the subsequent three months following each collection of data. Results. Patients who required hospitalization in the three months following each of the measurement sets had significantly different values for all parameters than patients who were not hospitalized. Thus, serum albumin (3.93 ± 0.39 vs. 3.74 ± 0.39 g/dl), serum creatinine (11.0 ± 3.7 vs. 9.1 ± 3.5 mg/dl), serum transferrin (181 ± 35 vs. 170 ± 34 mg/dl), serum prealbumin (33.6 ± 9.2 vs. 30.0 ± 10.1 mg/dl), and reactance (50.4 ± 15.6 vs. 43.0 ± 13.0 ohms) were higher for patients not hospitalized, whereas CRP (0.78 ± 0.89 vs. 2.25 ± 2.72 mg/dl) was lower in patients who were not hospitalized. All differences were statistically significant (P < 0.05 for all parameters). When multivariate analysis was performed, serum CRP and reactance values were the only statistically significant predictors of hospitalization (P < 0.05 for both). When a serum CRP concentration of 0.12 mg/dl was considered as a reference range (relative risk 1.0), the relative risk for hospitalization was 7% higher (relative risk = 1.07) for a CRP concentration of 0.92 mg/dl and was 30% (relative risk = 1.30) higher for a CRP concentration of 3.4 mg/dl. When a reactance value of 70 ohms was considered as a reference range with a relative risk of 1.0, the relative risk of hospitalization increased to 1.09 for a reactance value of 43 ohms and further increased to 1.14 for a reactance value of 31 ohms. Conclusions. The results of this study strongly indicate that both nutritional status and inflammatory response are independent predictors of hospitalization in CHD patients. CRP and reactance values by BIA are reliable indicators of hospitalization. Visceral proteins such as serum albumin, prealbumin, and transferrin are influenced by inflammation when predicting hospitalization. When short-term clinical outcomes such as hospitalizations are considered, markers of both inflammation and nutrition should be evaluated. [ABSTRACT FROM AUTHOR]

Measurement of the delivery of dialysis in acute renal failure. Background. Recent studies in patients with acute renal failure (ARF) have shown a relationship between the delivered dose of dialysis and patient survival. However, there is currently no consensus on the appropriate method to measure the dose of dialysis in ARF patients. In this study, the dose of dialysis was measured by blood- and dialysate-based kinetic methods in a group of ARF patients who required intermittent hemodialysis. Methods. Treatments were performed using a Fresenius 2008E volumetric hemodialysis machine with the ability to fractionally collect the spent dialysate. Single-, double-pool, and equilibrated Kt/V were determined from the pre-, immediate post-, and 30-minute post-blood urea nitrogen (BUN) measurements. The solute reduction index was determined from the collected dialysate, as well as the single- and double-pool Kt/V. Results. Forty-six treatments in 28 consecutive patients were analyzed. The mean prescribed Kt/V (1.11 ± 0.32) was significantly greater than the delivered dose estimated by single-pool (0.96 ± 0.33), equilibrated (0.84 ± 0.28), and double-pool (0.84 ± 0.30) Kt/V (compared with prescribed, each P < 0.001). There was no statistical difference between the equilibrated and double-pool Kt/V (P = NS). The solute removal index, as determined from the dialysate, corresponded to a Kt/V of 0.56 ± 0.27 and was significantly lower than the single-pool and double-pool Kt/V (each P < 0.001). Conclusion. Blood-based kinetics used to estimate the dose of dialysis in ARF patients on intermittent hemodialysis provide internally consistent results. However, when compared with dialysate-side kinetics, blood-based kinetics substantially overestimated the amount of solute (urea) removal. [ABSTRACT FROM AUTHOR]

Increased susceptibility to erythrocyte C5b-9 deposition and complement-mediated lysis in chronic renal failure. Background. Decreased red blood cell survival contributes to the anemia of chronic renal failure patients. Because patients on chronic dialysis therapy are frequently exposed to excessive complement activation, we investigated the susceptibility of this patient population to erythrocyte C5b-9 deposition, complement-mediated lysis, and ghost formation. Methods. We developed a flow cytometric assay using antibodies to both glycophorin and the C5b-9 complex to detect C5b-9 deposition on intact erythrocytes and erythrocyte ghosts. Serum C5b-9 levels and C5b-9 deposition on erythrocyte ghosts were measured by enzyme-linked immunosorbent assay. Results. A significant increase in C5b-9 deposition on intact erythrocytes was demonstrated in patients with advanced chronic renal failure (2.2 ± 0.5%) and in patients on chronic maintenance hemodialysis (2.3 ± 0.4%) compared with normal volunteers (0.9 ± 0.1%, P = 0.005 vs. chronic renal failure, P < 0.001 vs. chronic hemodialysis patients). There was also a significantly higher percentage of C5b-9–positive erythrocyte ghosts in patients with advanced chronic renal failure (20.6 ± 5%) and in chronic hemodialysis patients (15.5 ± 3.1%) compared with normal controls (2.6 ± 0.9%, P ≤ 0.001 vs. advanced chronic renal failure and chronic hemodialysis patients). Treatment of erythrocyte preparations with cobra venom factor, which activates the complement cascade, resulted in dramatic increases in the percentages of C5b-9–positive erythrocyte ghosts in patients with chronic renal failure (49.9 ± 6.9%) and in chronic hemodialysis patients (45.0 ± 4.2%) compared with normal volunteers (22.3 ± 2.7%, P < 0.001 vs. chronic renal failure and chronic hemodialysis patients). Erythrocyte membrane expression of the complement regulatory proteins CD59 and CD55 did... [ABSTRACT FROM AUTHOR]

Change in access blood flow over time predicts vascular access thrombosis. Background. Vascular access thrombosis accounts for at least $1 billion dollars in annual expenses and 25% of hospitalizations for chronic hemodialysis patients. Low vascular access blood flow (less than 800 ml/min) has been shown to modestly increase the relative risk for thrombosis in the subsequent three months. In this study, it is hypothesized that a time-dependent decrease in vascular access blood flow may be more predictive of subsequent thrombosis especially in vascular accesses with flows more than 800 ml/min, since it would indicate the development of a critical outlet stenosis in the graft. Methods . Ninety-five accesses in 91 CHD patients were prospectively followed over 18 months. Vascular access blood flow was measured every six months by the ultrasound dilution technique. Thrombotic events were recorded during the three study periods. Results . A total of 34 thrombotic events in 95 accesses were documented through the total study duration. Accesses that thrombosed had a 22% decrease in vascular access blood flow during the first observation period and a further 41% decrease during the second observation period as compared to 4% drop and 15% increase during the first and second observation periods, respectively, for accesses that did not thrombose. There was an estimated 13.6-fold (95%, confidence interval 2.68 to 69.16) increase in the relative risk of thrombosis for accesses with more than 35% decrease in vascular access blood flow compared to those accesses with no change in blood flow. There was no statistical difference in the average vascular access blood flow of all patients over the study period. Conclusions . Accesses that show a large (>15%) decrement in vascular access blood flow are associated with a high risk of thrombosis. Serial measurements of vascular access blood flow predict access thrombosis. [ABSTRACT FROM AUTHOR]