Canadian Hemodialysis Morbidity Study

Disturbances of acquired immunity in hemodialysis patients

Acquired immunity disturbances in hemodialysis (HD) patients are many and diverse. They are caused by uremia per se, the HD procedure, chronic renal failure complications, and therapeutic interventions for their treatment. Current data suggest that acquired immunity disturbances in HD patients concern mainly the T-lymphocyte and the antigen-presenting cell (APC). The T-lymphocyte-dependent immune response is deficient, predisposing to infections and inadequate response to vaccinations. In addition, APCs are preactivated, which seems to be responsible for the malnutrition-inflammation-atherosclerosis syndrome, and also affects T-lymphocyte function. At the molecular level it is assumed that the interaction between the APC and the T-lymphocyte is impaired. This disturbance is likely to concern the signal that results from the interaction between the major histocompatibility complex:peptide complex on APC surfaces and T-cell receptors on T-lymphocyte surfaces, or the signal that results from the interaction among the co-receptors of these two cells. The aim of the present review was to collect and classify the available clinical and experimental data in this area. Although many pieces are still missing from the puzzle, a better understanding of the responsible molecular mechanisms, will potentially lead to increased survival and a better quality of life in HD patients.

Protein and energy intake in advanced chronic kidney disease: how much is too much?

Uremic wasting is strongly associated with increased risk of death and hospitalization events in patients with advanced chronic kidney disease (CKD). Recent evidence indicates that patients with advanced chronic kidney disease are prone to uremic wasting due to several factors, which include the dialysis procedure and certain comorbid conditions, especially chronic inflammation and insulin resistance or deficiency. While the catabolic effects of dialysis can be readily avoided with intradialytic nutritional supplementation, there are no established alternative strategies to avoid the catabolic consequences of comorbid conditions other than treatment of their primary etiology. To this end, there is no indication that simply increasing dietary protein and energy intake above the required levels based on level of kidney disease is beneficial in patients with advanced chronic kidney disease. However, aside from the potential adverse effects such as uremic toxin production, dietary protein and energy intake in excess of actual needs might be beneficial in maintenance dialysis patients as it may lead to weight gain over time. Clearly, the role of obesity in advanced uremia needs to be examined in detail prior to making any clinically applicable recommendations, both in terms of ''low'' and ''high'' dietary protein and energy intake.

Prevention of sepsis during the transition to dialysis may improve the survival of transplant failure patients

Dialysis patients are at risk for sepsis, and the risk may be even higher among transplant failure patients because of previous or ongoing immunosuppression. The incidence and the consequences of sepsis as defined by International Classification of Diseases, Ninth Revision, Clinical Modification hospital discharge diagnoses codes were determined among 5117 patients who initiated dialysis after transplant failure between 1995 and 2004 in the United States. The overall sepsis rate was 11.8 per 100 patient years (95% confidence interval [CI] 11.5 to 12.1). Sepsis was highest in the first 6 mo after transplant failure (35.6 per 100 patient years [95% CI 29.4 to 43.0] between 0 to 3 mo after transplant failure; 19.7 per 100 patient years [95% CI 17.2 to 22.5] between 3 to 6 mo after transplant failure). In comparison, the sepsis rate among incident dialysis patients between 3 and 6 mo after dialysis initiation was 7.8 per 100 patient years (95% CI 7.3 to 8.3), whereas the sepsis rate among transplant recipients between 3 and 6 mo after transplantation was 5.4 per 100 patient years (95% CI 4.9 to 5.9). Patients who were > or =60 yr, obese patients, patients with diabetes, and patients with a history or peripheral vascular disease or congestive heart failure were at risk for sepsis. Transplant nephrectomy was not associated with septicemia. The role of continued immunosuppression and vascular access creation was not assessed and should be addressed in future studies. In a multivariate analysis, patients who were hospitalized for sepsis had an increased risk for death (hazard ratio 2.93; 95% CI 2.64 to 3.24; P < 0.001). Strategies to prevent sepsis during the transition from transplantation to dialysis may improve the survival of patients with allograft failure.

Is Chronic Kidney Disease Comparable to Diabetes as a Coronary Artery Disease Risk Factor?

BACKGROUND

Chronic kidney disease (CKD) is one of the known risk factors for coronary heart disease (CHD). Though electrocardiograms (ECGs) have limited accuracy in determining the true prevalence of CHD, we wondered whether CKD and diabetes mellitus (DM) controlled for hypertension (HTN), had similar prevalences of ECG abnormalities that could reflect underlying coronary heart disease.

METHOD

Data were collected for 5,942 men and women aged 30 to 69 years in the Tehran Lipid and Glucose Study (TLGS), a crosssectional phase of a large epidemiologic study first initiated in 1999. ECG findings of all subjects were coded according to Minnesota ECG coding criteria. The Whitehall criteria for abnormal ECG findings that could represent ischemia were utilized. Creatinine clearance (Crcl) was estimated using the Cockroft-Gault equation and diabetes was defined according to the American Diabetic Association (ADA) criteria. Subjects with moderate CKD and without DM were compared with the patients with DM without CKD. HTN prevalence was similar. The analysis was performed for all Whitehall ECG ischemia abnormalities combined, and separately for pathologic Q waves.

RESULTS

In spite of an overall similar prevalence of smoking, and a lower incidence of dyslipidemia and HTN, moderate CKD patients had a higher prevalence of Whitehall criteria abnormal ECG findings compared with the patients with DM. Over 19% of patients with CKD had abnormal ECG findings while 14.7% of diabetic patients had abnormal ECGs (P = 0.02). The prevalence of Q waves was 11.5% in patients with CKD and 10.8% in patients with DM. In an age-matched subgroup of patients with DM and no CKD, the prevalence of ECG abnormalities was 19.3%, similar to the patients with moderate CKD and no DM (19.7%) (P = 0.9). The prevalence of pathologic Q waves in an age-matched group was 11.45%, compared with 11.5%, respectively.

CONCLUSION

Moderate CKD is a major risk factor for the development of the Whitehall ECG criteria which have been associated with ischemic heart disease. The importance of CKD as a risk factor for ECG abnormalities is comparable with DM. Patients with moderate CKD probably are candidates for aggressive CHD risk modification.

Vascular access thrombosis prophylaxis

Vascular access thrombosis in the hemodialysis patient leads to significant cost and morbidity. Fistula patency supersedes graft patency, therefore obtaining a mature functioning fistula in patients approaching end-stage renal disease (ESRD) by early patient education and referral needs to be practiced. Current methods to maintain vascular access patency rely on early detection and radiologic or surgical prevention of thrombosis. Study of thrombosis biology has elucidated other potential targets for the prophylaxis of vascular access thrombosis. The goal of this review is to examine the current available methods for vascular access thrombosis prophylaxis.

Hyperhomocysteinaemia and vascular access thrombosis among chronic hemodialysis patients in Taiwan: a retrospective study

Vascular access thrombosis (VAT) is an important cause of morbidity for chronic haemodialysis (HD) patients. Some risk factors for VAT have been well-defined for chronic HD patients from western countries. However, only a few such factors have been confirmed for Taiwanese patients. This study attempted to determine the association between hyperhomocysteinaemia and the incidence of VAT for chronic HD patients in Taiwan. We retrospectively enrolled a total of 196 patients into this study during 2003. The patients were separated into VAT (n = 142) and control (n = 54) group. The participants of the VAT group were identified as those having one or more VAT, and the participants of the control group were those with no VAT in the past. The mean follow-up period was 48 months. The mean serum homocysteine levels were 29.5 +/- 9.6 and 29.1 +/- 9.5 micromol/l for the VAT (n = 142) and the control (n = 54) group, respectively. There was no significant difference in the level of homocysteine between the VAT and the control group (p = 0.70). Female chronic HD patients had significantly greater mean total homocysteine levels than male (30.89 micromol/l, 95% CI 28.84-32.94 vs. 28.06 micromol/l, 95% CI 26.32-29.82, respectively, p = 0.038). That synthetic graft was a significant risk factor for VAT was determined using multivariate logistic regression analysis. There was no association between serum total homocysteine levels and the incidence of VAT in chronic HD patients in Taiwan.

Predictors and outcome of catheter-related bacteremia in children on chronic hemodialysis

Tunneled central venous catheters are often used in children on chronic hemodialysis. This study was done to evaluate the spectrum of catheter-related bacteremia (CRB) and to determine predictors of recurrent CRB in children on hemodialysis. Chart review was performed in 59 children from a pediatric dialysis unit with chronic, tunneled, cuffed hemodialysis catheters between January 1999 and December 2003. CRB was diagnosed in 48 of 59 (81%) patients. The incidence of CRB was 4.8/1,000 catheter days. Overall catheter survival (290+/-216 days) was significantly longer than infection-free catheter survival (210+/-167 days, p<0.05). Organisms isolated were gram-positive in 67%, gram-negative in 14%, and polymicrobial in 19%. Systemic antibiotics cleared CRB in 34% and an additional 23% cleared with the inclusion of antibiotic-heparin locks; 43% required catheter exchange. There was a significant likelihood of early catheter exchange with polymicrobial CRB (p<0.01). Catheter loss occurred from infection in 63%. Risk factors for CRB included young age (<10 years) and presence of human immunodeficiency virus (HIV) infection. Patients with >2 initial positive blood cultures (p<0.0001) had a significantly higher rate of recurrence after 6 weeks of initial treatment. In conclusion, CRB remains a major determinant of catheter loss. However, overall catheter survival is longer than infection-free catheter survival, suggesting that systemic antibiotics with antibiotic-heparin locks should be the initial step in the management of CRB and this approach may salvage some catheters.

Risk Equation Determining Unsuccessful Cannulation Events and Failure to Maturation in Arteriovenous Fistulas (REDUCE FTM I)

Fistulas are the preferred permanent hemodialysis vascular access but a significant obstacle to increasing their prevalence is the fistula's high "failure to mature" (FTM) rate. This study aimed to (1) identify preoperative clinical characteristics that are predictive of fistula FTM and (2) use these predictive factors to develop and validate a scoring system to stratify the patient's risk for FTM. From a derivation set of 422 patients who had a first fistula created, a prediction rule was created using multivariate stepwise logistic regression. The model was internally validated using split-half cross-validation and bootstrapping techniques. A simple scoring system was derived and externally validated on 445 different, prospective patients who received a new fistula at five large North American dialysis centers. The clinical predictors that were associated with FTM were aged > or =65 yr (odds ratio [OR] 2.23; 95% confidence interval [CI] 1.25 to 3.96), peripheral vascular disease (OR 2.97; 95% CI 1.34 to 6.57), coronary artery disease (OR 2.83; 95% CI 1.60 to 5.00), and white race (OR 0.43; 95% CI 0.24 to 0.75). The resulting scoring system, which was externally validated in 445 patients, had four risk categories for fistula FTM: low (24%), moderate (34%), high (50%), and very high (69%; trend P < 0.0001). A preoperative, clinical prediction rule to determine fistulas that are likely to fail maturation was created and rigorously validated. It was found to be simple and easily reproducible and applied to predictive risk categories. These categories predicted risk of FTM to be 24, 34, 50, and 69% and are dependent on age, coronary artery disease, peripheral vascular disease, and race. The clinical utility of these risk categories in increasing rates of permanent accesses requires further clinical evaluation.

In Preparation for a Treatment Guideline for Suitable Vascular Access Repair in Japan

In cases of vascular access (VA) for hemodialysis including arteriovenous fistula and arteriovenous graft, venipuncture and hemostasis are usually repeated three times a week. Accordingly, it is assumed that VA vascular disorders are worsened following long-term hemodialysis. In particular, angiostenosis frequently occurs and results in insufficient blood flow or increased venous pressure. Additionally, stenosis is a major cause of VA occlusion. While VA intervention treatment is mainstream for VA stenosis, its major advantage lies in its less invasiveness because it is a percutaneous treatment. A further advantage of this treatment procedure is that the existing VA can be preserved intact. For practical use of VA intervention treatment, however, compliance with the therapeutic indication guideline is required. In K/DOQI of the United States, such a guideline has already been formulated based on evidence and specialist opinion, while the guideline of the European Vascular Access Society is presented in the form of a flowchart. The Japanese Society for Dialysis Therapy is currently preparing a guideline for the construction and maintenance of VA, which introduces the timing and principles of repair of VA in the following six categories: (i) stenosis; (ii) occlusion; (iii) venous hypertension; (iv) steal syndrome; (v) excess blood flow; and (vi) infection. Except for infection, most of the treatments for these events involve VA intervention, thus the need for the guideline for VA intervention treatment is becoming widely recognized.

Clinical Course Associated with Vascular Access Type in a National Cohort of Adolescents Who Receive Hemodialysis: Findings from the Clinical Performance Measures and US Renal Data System Projects

Limited research has described clinical outcomes that are associated with the type of vascular access in pediatric patients who receive maintenance hemodialysis. This retrospective cohort study examined prevalent pediatric patients who were aged 12 to <18 yr and identified in the 2000 ESRD Clinical Performance Measures Project as receiving in-center hemodialysis. Vascular access type as of December 31, 1999, was identified. These patients were linked with 1 yr of data (January 1, 2000, through December 31, 2000) from US Renal Data System standard analytic files that allow for the comparison of rates of hospitalizations and access complications by access type. Of the 418 patients who met inclusion criteria, the mean age was 15.6 yr, 53% were male, 49% were white, the mean time on dialysis was 22 mo, and 42% had a structural/urologic cause of ESRD; 42% of patients had an arteriovenous graft or fistula, and 58% had a vascular catheter. Patients with a vascular catheter as compared with those with a graft or fistula had the following adjusted relative risks (95% confidence interval): 1.84 (1.38 to 2.44) for hospitalization for any cause, 4.74 (2.02 to 11.14) for hospitalization as a result of infection, and 2.72 (2.00 to 3.69) for a complication of vascular access. Vascular catheters are the predominant access type in adolescent patients who receive maintenance hemodialysis and are associated with significantly more hospitalizations and complications.

Reducing dialysis associated bacteraemia, and recommendations for surveillance in the United Kingdom: prospective study

PROBLEM

Bacteraemia in dialysis units accounts for major morbidity, mortality, and antibiotic usage. Risk is much greater when lines rather than fistulas are used for haemodialysis. Surveillance is critical for infection control, but no standardised surveillance scheme exists in the United Kingdom.

DESIGN

Prospective study in a London dialysis unit of the implementation and applicability of a dialysis associated bacteraemia surveillance scheme developed in the United States and its effect on bacteraemia, antibiotic usage, and admission.

SETTING

Hammersmith Hospital dialysis unit, London, where 112 outpatients receive dialysis three times weekly. Between June 2002 and December 2004, 3418 patient months of data were collected.

KEY MEASURES FOR IMPROVEMENT

Successful adoption of the scheme and reductions in bacteraemia rates, antibiotic usage, and admission to hospital. Strategy for improvement Embedding the surveillance scheme in the unit's clinical activity.

EFFECTS OF CHANGE

Raised awareness of bacteraemia prevention, prudent antibiotic prescribing, and the need for improved provision of vascular access. The scheme required two hours a month of consultant time. Significant downward trends were seen in bacteraemia rates and antibiotic usage: mean rate ratios from quarter to quarter 0.90 (95% confidence interval 0.85 to 0.94) and 0.91 (0.87 to 0.96), respectively. The rate of admission to hospital also showed a significant downward trend, with admissions directly connected to access related infection declining more rapidly: mean rate ratio of successive quarters 0.90 (0.84 to 0.96). The overall proportion of patients dialysed through catheters was significantly higher than in US outpatient centres (62.3% v 29.4%, P < 0.01). Study data were successfully used in a business case to improve access provision.

LESSONS LEARNT

Dialysis specific surveillance of bacteraemia is critical to infection control in dialysis units and improving quality of care. Such a scheme could be adopted across the United Kingdom.

Physical activity patterns in chronic hemodialysis patients: comparison of dialysis and nondialysis days

OBJECTIVE

To determine physical activity patterns in chronic hemodialysis patients with a specific emphasis on the difference between dialysis and nondialysis days. Design A cross-sectional single-center study.

SETTING

Vanderbilt University Outpatient Dialysis Unit.

PATIENTS

Twenty current chronic hemodialysis patients: 10 male, 10 female; 15 black, 5 white; mean age, 50.1 +/- 9.9 years; height, 164.5 +/- 10.9 cm; weight, 82.5 +/- 15.4 kg; length on dialysis, 57.3 +/- 45.3 months.

METHODS

Minute-by-minute physical activity was assessed over a 7-day period using a triaxial accelerometer, which consists of raw numbers or counts calculated by the 3 axes of the accelerometer (PA counts). PA counts were extrapolated on a daily and hourly basis. Physical functioning tests included: sit-to-stand, 6-minute walk, and 1-repetition maximal leg press exercise. Laboratory values for serum concentrations of albumin, prealbumin, C-reactive protein, and cholesterol were also collected.

MAIN OUTCOME MEASURE

PA counts.

RESULTS

Total PA counts were significantly lower on dialysis days when compared with nondialysis days (128,279 +/- 74,009 versus 168,744 +/- 95,168, respectively, P = .025). The average PA counts during the 4-hour dialysis time period were significantly lower on dialysis days when compared with nondialysis days (3,086 +/- 3,749 versus 11,070 +/- 7,695, respectively, P = .001). At postdialysis hours 1 and 2, PA counts on dialysis days were significantly higher than on nondialysis days (11,410 +/- 5,340 versus 9,082 +/- 6,646, P = .008, and 14,048 +/- 9,728 versus 8,662 +/- 6,433, P = .016, respectively). By postdialysis hour 4, PA counts on dialysis days had significantly decreased when compared with nondialysis days (6,068 +/- 6,268 versus 10,512 +/- 7,420 PA counts, P = .01, respectively). From postdialysis hours 5 to 20, there was no significant difference in PA counts between dialysis and nondialysis days.

CONCLUSION

This study shows that physical activity is lower on dialysis days when compared with nondialysis days, and this decrease is caused by the lack of activity during the 4-hour hemodialysis procedure. New behavior modification strategies involving physical activity, both during hemodialysis and on nondialysis days, must be examined in this patient population.

Prealbumin, mortality, and cause-specific hospitalization in hemodialysis patients

BACKGROUND

Prealbumin (transthyretin) is a hepatic secretory protein thought to be important in the evaluation of nutritional deficiency and nutrition support. Prior studies have suggested that the serum prealbumin concentration is independently associated with mortality in hemodialysis patients, even with adjustment for serum albumin and other nutritional parameters.

METHODS

To determine whether prealbumin was independently associated with mortality and morbidity (cause-specific hospitalization) in hemodialysis patients, we analyzed data on 7815 hemodialysis patients with at least one determination of serum prealbumin during the last three months of 1997. Unadjusted, case mix-adjusted, and multivariable-adjusted relative risks of death were calculated for categories of serum prealbumin using proportional hazards regression. We also determined whether the prealbumin concentration was associated with all-cause, cardiovascular, infection-related, and vascular access-related hospitalization.

RESULTS

The relative risk (RR) of death was inversely related to the serum prealbumin concentration. Relative to prealbumin > or =40 mg/dL, the adjusted RRs of death were 2.41, 1.85, 1.49, and 1.23 for prealbumin <15, 15-20, 20-25, and 25-30 mg/dL, respectively. The adjusted RRs of hospitalization due to infection were 2.97, 1.95, 1.81, and 1.61 for prealbumin <15, 15-20, 20-25, and 25-30 mg/dL, respectively. The adjusted RRs of vascular access-related hospitalization were 0.48, 0.52, 0.58, and 0.71 for prealbumin <15, 15-20, 20-25, and 25-30 mg/dL, respectively. While serum albumin was strongly associated with mortality and all-cause hospitalization, it was not associated with hospitalization due to infection, and lower levels were associated with higher rather than lower rates of vascular access-related hospitalization.

CONCLUSION

In hemodialysis patients, lower prealbumin concentrations were associated with mortality and hospitalization due to infection, independent of serum albumin and other clinical characteristics. Higher prealbumin concentrations were associated with vascular access-related hospitalization. In light of these findings, more intensive study into the determinants and biological actions of prealbumin (transthyretin) in end-stage renal disease is warranted.

Thrombosed arteriovenous fistula for hemodialysis access is characterized by a marked inflammatory activity

BACKGROUND

Thrombosis is the dominant cause of failure of arteriovenous fistulas for hemodialysis access. Vascular inflammation, an important pathologic change in various human vascular diseases, may be involved in the thrombotic process of arteriovenous fistulas.

METHODS

The inflammatory activities of 23 thrombosed and 13 non-thrombosed stenotic arteriovenous fistulas were compared by investigating the contents of macrophages and lymphocytes, and the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6) using immunohistochemistry method. The expression of matrix metalloproteinase (MMP)-2 and MMP-9, which play important roles in thrombosis of human coronary artery, was also investigated. The immunoreaction results were characterized using a semiquantitative scoring system.

RESULTS

The macrophage and lymphocyte contents of the thrombosed group were abundant, and markedly greater than those of the non-thrombosed group (P < 0.001 and P = 0.001, respectively). The infiltration of macrophages and neovasculature were spatially closely correlated. The expressions of VCAM-1, IL-6, and TNF-alpha, but not ICAM-1, were significantly higher in the thrombosed group (P = 0.031, P = 0.010, P < 0.001, and P= 1.000, respectively). The expression of MMP-2 was not different in either groups (P = 0. 344). Differential expression of MMP-9 by macrophages near the vascular lumen, but not those distant from the lumen, was observed in most thrombosed specimens.

CONCLUSION

This study demonstrated that the thrombosed arteriovenous fistula was characterized by marked inflammation. We hypothesize that the preferential expression of MMP-9 at luminal edge may cause disruption of the anticoagulant endothelial barrier and contribute to luminal thrombosis of arteriovenous fistulas.

Thromboembolism and anticoagulant management in hemodialysis patients: A practical guide to clinical management

The need for anticoagulation in dialysis patients is common and the incidence of venous thromboembolism (VTE) and atrial fibrillation in this population is high. While direct data are lacking on the management of anticoagulation in dialysis patients, careful weighing of risks and benefits on the basis of evidence from other populations is crucial. VTE should be managed with adjusted dose warfarin for most patients. Placement of an inferior vena cava filter is a reasonable option for those patients with unacceptable bleeding risks. Studies are ongoing to assess the safety of some low-molecular-weight heparins (LMWH), which may potentially be useful for long-term anticoagulation in hemodialysis patients. In atrial fibrillation the available data on risk of bleeding, risk of stroke, and patient preferences should all be taken into account when considering long-term anticoagulation. We have constructed an evidence model to help quantitate the risks and benefits for an individual patient. The impact of dialysis on risk of bleeding is such that the risk of bleeding will outweigh the benefit in many patients, and anticoagulation will not be used: in some of these patients aspirin therapy may be an alternative. Finally, in the area of prevention of graft and access thrombosis, some randomized controlled trials are available, but none have to date shown benefit from anticoagulation for primary or secondary prevention of thrombosis, and the risk of bleeding in these studies was high.

Vein wall dissection: a rare puncture-related complication of brachiocephalic fistula. Gray-scale and color Doppler sonographic findings

We describe a case of brachiocephalic fistula vein wall dissection (VWD) occurring in a 36-year-old female hemodialysis patient. Unlike subcutaneous or subfascial infiltrations for which the mechanism is blood extravasation, VWD seems to be due to disruption of the fistula vein layers caused by misplacement of the outflow (venous) needle bevel. In this setting, the pressure of the dialysis blood pump acts as the driving force of the dissecting column, extending it proximally. Gray-scale and color Doppler sonography proved to be very useful in the differential diagnosis of VWD, particularly with thrombosis of the fistula. Sonography also helped us decide when to resume cannulations.

Haemodialysis vascular access problems in Canada: results from the Dialysis Outcomes and Practice Patterns Study (DOPPS II)

BACKGROUND

The optimal vascular access for chronic maintenance haemodialysis (HD) is the native arteriovenous fistula (AVF). Vascular access practice patterns are reported for a Canadian cohort of patients from the Dialysis Outcomes and Practice Patterns Study (DOPPS II).

METHODS

DOPPS II is a prospective, observational study in 12 countries, including Canada. A representative random sample of 20 Canadian HD facilities and patients within those units were studied during 2002-2004. Canadian results were compared with those found in Europe and the USA.

RESULTS

AVF use in Canadian prevalent (53%) and incident (26%) patients was lower than Canadian guidelines recommend (60%), and lower than in Europe [prevalent (74%), incident (50%)]. Despite 85% of Canadian HD patients having seen a nephrologist for > 1 month prior to starting dialysis, central venous catheter use in Canada (33% in prevalent patients, 70% in incident patients) was much higher than in Europe (prevalent 18%, incident 46%) and slightly higher than in the USA (prevalent 25%, incident 66%). This pattern is contrary to the preferences of Canadian medical directors and vascular access surgeons. The typical time from referral until permanent vascular access creation is substantially longer in Canada (61.7 days) than in Europe (29.4 days) or the USA (16 days). This longer delay time and higher catheter use in Canada may be a consequence of the significantly lower number of access surgeons per 100 HD patients in Canada (2.9) compared with the USA (8.1) and Europe (4.6). Furthermore, the median hours per week devoted to vascular access-related surgery per 100 patients is substantially lower in Canada (0.027 h) compared with the USA (0.082 h) and Europe (0.059 h).

CONCLUSION

These findings suggest that Canadian chronic HD patients often rely on central venous catheters for vascular access, despite their known association with numerous detrimental outcomes in HD. Nephrologists, vascular access surgeons, interventional radiologists, other physicians and health care funding bodies must be more broadly educated about the priority of AVF creation as the preferred vascular access for chronic HD patients. They must work together to secure both the human and financial resources and other health care system enhancements to increase AVF creation rates in a timely manner.

Coronary artery bypass graft mycotic aneurysms in a dialysis patient

Infection is a common problem in dialysis patients and ranks second behind cardiovascular disease as a major cause of death. The major causes of infections, mainly bloodstream infections, often are related to dialysis access. Metastatic infectious complications have been reported frequently in the course of such bacteremias. We report the case of a 79-year-old dialysis patient who was admitted with recurrent catheter-related bacteremia caused by methicillin-resistant Staphylococcus aureus. Echocardiography and a computed tomographic scan of her chest showed multiple coronary artery bypass graft mycotic aneurysms. Despite prompt dialysis catheter removal and antibiotic treatment, she had progressive deterioration of her hemodynamic and mental status and eventually died of profound sepsis. An autopsy confirmed computed tomographic findings, plus extensive suppuration involving the left atrial and ventricular myocardium and upper lobe of the left lung. To our knowledge, this is the first report of coronary artery graft aneurysms complicating infective endocarditis in a dialysis patient.

Clinical and economic outcomes of Staphylococcus aureus septicemia in ESRD patients receiving hemodialysis

BACKGROUND

Serious infections are a common problem in patients with end-stage renal disease (ESRD). The purpose of this study is to identify clinical and economic consequences of hospitalizations for septicemia caused by Staphylococcus aureus in hemodialysis patients with ESRD.

METHODS

We conducted a retrospective analysis of data obtained from the US Renal Data System to determine lengths of stay and Medicare paid costs for index hospitalizations and episodes of care for patients with ESRD hospitalized with septicemia caused by S aureus. Factors associated with hospital length of stay and Medicare paid costs were examined in multivariate analysis.

RESULTS

A total of 11,572 patient admissions with septicemia caused by S aureus were included; 20.7% of patients developed 1 or more complications. Average length of stay for the index admission was 13.0 days, and 11.8% of patients were readmitted within 12 weeks for care related to S aureus. Average Medicare cost for the index admission was 17,307 dollars. Average episodic cost of care, including the index hospitalization, outpatient visits, and readmissions related to S aureus during the subsequent 12 weeks, was 20,067 dollars. S aureus--related complications were associated with greater episodic costs of care: no complications, 18,476 dollars; one complication, 25,804 dollars (P < 0.05 versus no complications); and 2 or more complications, 32,102 dollars (P < 0.05 versus no complications). In multivariate analysis, complications resulted in increased mean lengths of stay of 4 to 7 days, and complications were among the strongest predictors of total episodic costs.

CONCLUSION

Patients with septicemia caused by S aureus had costly and lengthy hospitalizations, which frequently were associated with clinically and economically important complications, including hospital readmissions.

Hyperhomocysteinemia and arteriovenous fistula thrombosis in hemodialysis patients

BACKGROUND

To date, the relationship between vascular access (VA) failure and plasma total homocysteine level has been investigated only in mixed dialysis populations (ie, patients with a native arteriovenous [AV] fistula or arterial graft), whereas almost no data exist for hemodialysis patients with a native AV fistula.

METHODS

In this prospective cohort study, we examined the relationship between plasma total homocysteine level and the methylenetetrahydrofolate reductase (MTHFR) gene and VA-related incident morbidity in a cohort of 205 hemodialysis patients, all with a native AV fistula.

RESULTS

During follow-up, 78 patients experienced 1 or more VA thrombotic episodes. Patients with incident VA thrombosis had a significantly greater plasma total homocysteine level compared with patients without this event (P = 0.046). In Kaplan-Meier survival analysis, the hazard ratio for VA thrombosis increased in parallel with homocysteine level, such that patients in the third homocysteine level tertile had a relative risk for this outcome 1.72 times (95% CI, 1.21 to 2.24) greater than in those in the first tertile (log-rank test, 6.81; P = 0.009). In a multiple Cox regression model, plasma total homocysteine level was confirmed to be an independent predictor of AV fistula outcome. Plasma total homocysteine level was significantly greater (P < 0.001) in patients with the TT genotype of the MTHFR gene than in those with the CT or CC genotype.

CONCLUSION

VA thrombosis in dialysis patients is associated with hyperhomocysteinemia. Intervention studies are needed to clarify whether decreasing plasma homocysteine concentrations may prevent VA failure in hemodialysis patients.

Growth and nutrition in children with chronic kidney disease

Growth failure remains an important problem for children with kidney disease secondary to medical kidney disease or urologic disorders. In children with chronic kidney disease, growth remains suboptimal even with energy intake above 80% of the recommend daily allowance. Adults who had chronic kidney disease as children frequently report dissatisfaction with final adult height. Additionally, growth failure in children with end-stage renal disease is associated with adverse clinical outcomes, including more frequent hospitalizations and increased mortality. This review describes the prevalence and morbidity associated with growth retardation in US children with chronic kidney disease. Additionally, available strategies to optimize growth and nutrition and current controversies in nutritional management and assessment of nutritional status in children with chronic kidney disease are discussed.

Arteriovenous fistula outcomes in the era of the elderly dialysis population

BACKGROUND

The growth of patients > or =65 years on hemodialysis is increasing. Guidelines recommend arteriovenous fistula (AVF) access but their outcomes in elderly patients are controversial. This study compared the outcomes of AVF in patients <65 years old (65- group) versus those > or =65 years old (65+ group).

METHODS

This retrospective analysis of prospectively collected data included 444 incident, first-time AVF created in a large dialysis center between January 1, 1995 and July 1, 2003. The primary outcome of AVF cumulative patency was evaluated using Kaplan-Meier survival analysis with log-rank test comparison. A Cox model determined factors associated with AVF loss.

RESULTS

One hundred ninety-six patients (44%) were in the 65+ group. In total, there were 230 (52.2%) radiocephalic, 186 (42.2%) brachiocephalic, and 25 (5.6%) basilic vein transposed AVF. The one-year AVF cumulative survival was 75.1% (65+ group) and 79.7% (65- group); the five-year survival was 64.7% (65+ group) and 71.4% (65- group). The overall total procedure, angioplasty, thrombolysis, and revision rates per access-year were 0.83, 0.30, 0.66, and 0.16, respectively. The 65+ group had a relative risk of 1.7 of their AVF failing to mature compared with the 65- group. Multivariate analysis yielded these variables significant for AVF loss: male sex HR 0.63 (95% CI 0.44-0.91), coronary artery disease HR 2.1 (95% CI 1.5-3.0), and Caucasian ethnicity HR 0.63 (95% CI 0.44-0.91).

CONCLUSION

Age should not be a limiting factor when determining candidacy for AVF creation due to equivalent survival and procedural rates. Failure of fistula maturation is a primary concern to patients of all ages and demands further study.

Future of home haemodialysis in Australia and New Zealand (Review Article)

Maintenance haemodialysis (HD) was pioneered in Seattle and rapidly became home-based. When dialysis treatment began in Australia and New Zealand, home haemodialysis (HHD) became the predominant form of dialysis. When compared with in-centre conventional dialysis, HHD is associated with superior survival and quality of life and is cheaper. There is currently significant interest in increasing the frequency and duration of dialysis and in providing more flexible dialysis regimens for patients. If the likely benefits of these treatment changes are to be fully realized HHD and self care HD services will need to expand. Dialysis units in Australia and New Zealand are better equipped than most to respond to this challenge.

Protein and energy: recommended intake and nutrient supplementation in chronic dialysis patients

Nutritional status is an important predictor of clinical outcome in end-stage renal disease (ESRD) patients, especially in patients on chronic hemodialysis. Uremic malnutrition is strongly associated with increased risk of death and hospitalization events in this patient population, and decreased muscle mass is the most significant predictor of these outcomes. Several factors that influence protein metabolism predispose chronic hemodialysis patients to increased catabolism and loss of lean body mass. The available evidence suggests that low protein and energy intake associated with advanced uremia along with catabolic consequences of dialytic therapies can lead to the development of uremic malnutrition. Recent studies show that the hemodialysis procedure induces a net protein catabolic state at the whole-body level as well as skeletal muscle. There is evidence to suggest that these undesirable effects are due to decreased protein synthesis and increased proteolysis. Provision of nutrients, either in the form of intradialytic parenteral nutrition or oral feeding during hemodialysis, can adequately compensate for the catabolic effects of the hemodialysis procedure. While the mechanisms of these effects are not studied in detail, changes in extracellular amino acid concentrations, along with certain anabolic hormones such as insulin, are important mediators of these actions.

Influence of Intravenous Drug Abuse on Vascular Access Placement and Survival in HIV-Seropositive Patients

BACKGROUND

The influence of intravenous drug abuse (IVDA) on hemodialysis access placement practices and access survival in HIV-infected patients is unknown.

METHODS

We conducted a retrospective study of 60, HIV seropositive, maintenance hemodialysis patients. Type of access and assisted access survival (measured from date of placement) were compared in those with (77%) and without (23%) a history of IVDA.

RESULTS

Mean age was 37.8 years, mean baseline serum albumin was 2.9 g/dl and median CD4 count was 222 cells/mm3. Fifteen patients, all IVDA, were dialyzed using only tunneled catheters (median number of catheters per person (range): 2.5 (1-11)). There were longer delays in creation of a permanent access (p = 0.08), but no difference in the type of permanent access placed in IVDA versus the non-IVDA group. Over 1,051 cumulative months of access follow-up, 134 tunneled catheters, 28 grafts and 19 fistulae were placed, with observed failure rates of 1 per 4.7 access-months, 1 per 19.7 access-months, 1 per 38.2 access-months, respectively. The adjusted relative hazard of access failure for grafts versus catheters was 0.41 (95% CI: 0.23, 0.72; p = 0.002) and for fistulae versus catheters was 0.21 (95% CI: 0.08, 0.52; p = 0.001). Thirty-two percent of accesses were removed due to infection, an infection removal rate for catheters of 1 per 7.8 access-months and for grafts of 1 per 62.5 access-months; all graft infections occurred in the IVDA group. No fistula was removed due to infection.

CONCLUSION

Fistulae are the first line of choice for hemodialysis access in HIV-seropositive patients regardless of IVDA history; if not feasible, graft placement in non-IVDA or abstinent IVDA patients is recommended. In those with active IVDA, the optimal method of renal replacement therapy and type of hemodialysis access remain uncertain.

Type of vascular access and survival among incident hemodialysis patients: the Choices for Healthy Outcomes in Caring for ESRD (CHOICE) Study

Arteriovenous fistulae (AVF) have advantages over arteriovenous grafts (AVG) and central venous catheters (CVC), but whether AVF are associated independently with better survival is unclear. Recent studies showing such a survival benefit did not include early access experience or account for changes in access type over time and did not include data on some important confounders. Reported here are survival rates stratified by the type of access in use up to 3 yr after initiation of hemodialysis among 616 incident patients who were enrolled in the Choices for Healthy Outcomes in Caring for ESRD (CHOICE) Study. A total of 1084 accesses (185 AVF, 296 AVG, 603 CVC) were used for a total of 1381 person-years. At initiation, 409 (66%) patients were using a CVC, 122 (20%) were using an AVG, and 85 (14%) were using an AVF. After 6 mo, 34% were using a CVC, 40% were using an AVG, and 26% were using an AVF. Annual mortality rates were 11.7% for AVF, 14.2% for AVG, and 16.1% for CVC. Adjusted relative hazards (RH) of death compared with AVF were 1.5 (95% confidence interval, 1.0 to 2.2) for CVC and 1.2 (0.8 to 1.8) for AVG. The increased hazards associated with CVC, as compared with AVF, were stronger in men (n = 334; RH = 2.0; P = 0.01) than women (n = 282; RH = 1.0 for CVC; P = 0.92). These results strongly support existing clinical practice guidelines and suggest that the use of venous catheters should be minimized to reduce the frequency of access complications and to improve patient survival, especially among male hemodialysis patients.

Effects of hemodialysis on protein metabolism

Uremic malnutrition, as evidenced by decreased muscle mass, is strongly associated with increased risk of death and hospitalization events in chronic hemodialysis (CHD) patients. Several factors that influence protein metabolism predispose CHD patients to increased catabolism and loss of lean body mass. It has been long suspected that the hemodialysis (HD) procedure is a net catabolic event. Recent studies show that the HD procedure indeed induces a net protein catabolic state at the whole-body level as well as in skeletal muscle. There is evidence to suggest that these undesirable effects are caused by decreased protein synthesis and increased proteolysis. Animal studies suggest that decreased protein synthesis is likely mediated by the significant decrease in plasma amino acid concentrations during HD. On the other hand, increased protein degradation is, at least in part, mediated by the HD-associated inflammatory response.

Radiocephalic wrist arteriovenous fistula for hemodialysis: meta-analysis indicates a high primary failure rate

OBJECTIVE

To improve the precision of the estimates of primary failure rates and primary and secondary 1 year patency of radial-cephalic arteriovenous fistulas (RCAVF) for hemodialysis.

DESIGN

Meta-analysis.

MATERIALS AND METHODS

A Medline search was performed of the English language medical literature between January 1970 and October 2002. Key words that were searched included radiocephalic fistula, arteriovenous shunt, Brescia-Cimino fistula and patency. Primary failure, primary and secondary patency rates were analysed using the standard mixed effects model, which allows for variability between the different studies.

RESULTS

Eight prospective and 30 retrospective studies were included. The analysis showed a pooled estimated primary failure rate of 15.3% (95% CI: 12.7-18.3%). In addition, the pooled estimated primary and secondary patency rates of 62.5% (95% CI: 54.0-70.3%) and 66.0% (95% CI: 58.2-73.0%), respectively, were calculated. Subgroup analysis concerning various study characteristics, including study year, gender and age, did not reveal statistically significant differences.

CONCLUSION

Although, the autogenous RCAVF is considered to be the primary choice for vascular access, this meta-analysis indicates a high primary failure rate and only moderate patency rates at 1 year of follow-up.

Relationship among catheter insertions, vascular access infections, and anemia management in hemodialysis patients

BACKGROUND

Arteriovenous fistulas are the recommended permanent vascular access (VA) for chronic hemodialysis. However, in the United States most patients begin chronic hemodialysis with a catheter. Recent data suggest that VA type contributes to recombinant human erythropoietin (rHuEPO) resistance. We examined catheter insertions, VA infections, and anemia management in Medicare, rHuEPO-treated, chronic hemodialysis patients.

METHODS

We compared hemoglobin values and rHuEPO and intravenous iron dosing with concurrent catheter insertions and VA infections in 186,348 period-prevalent patients in 2000. We studied anemia management after catheter insertions and VA infections in 67,410 incident patients from 1997 to 1999. Multiple linear regression models examined follow-up hemoglobin and rHuEPO dose per week (rHuEPO/wk) by numbers of catheter insertions and hospitalizations for VA infection.

RESULTS

In the prevalent cohort, increasing temporary and permanent catheter insertions and VA infections were associated with slightly lower hemoglobin, higher rHuEPO doses, and higher intravenous iron doses. In the incident cohort, compared to patients with no VA infections or no catheter insertions (temporary or permanent), respectively, patients with 2+ VA infections or 2+ catheter insertions had 0.12 g/dL and 0.06 g/dL lower mean hemoglobin (P = 0.0028 and P < 0.0001), and 25.7% and 12.2% higher mean rHuEPO/wk (P < 0.0001).

CONCLUSION

Higher rHuEPO doses may be required to maintain similar or slightly lower mean hemoglobin values among chronic hemodialysis patients with higher numbers of catheter insertions and VA infections, compared to patients without any.

The differential impact of risk factors on mortality in hemodialysis and peritoneal dialysis

BACKGROUND

While the survival ramifications of dialysis modality selection are still debated, it seems reasonable to postulate that outcome comparisons are not the same for all patients at all times. Trends in available data indicate the relative risk of death with hemodialysis (HD) compared to peritoneal dialysis (PD) varies by time on dialysis and the presence of various risk factors. This study was undertaken to identify key patient characteristics for which the risk of death differs by dialysis modality.

METHODS

Analyses utilized incidence data from 398,940 United States Medicare patients initiating dialysis between 1995 and 2000. Proportional hazards regression identified the presence of diabetes, age, and the presence of comorbidity as factors that significantly interact with treatment modality. Stratifying by these factors, proportional and nonproportional hazards models were used to estimate relative risks of death [RR (HD:PD)].

RESULTS

Of the 398,940 patients studied, 11.6% used PD as initial therapy, 45% had diabetes mellitus (DM), 51% were 65 years or older, and 55% had at least one comorbidity. Among the 178,693 (45%) patients with no baseline comorbidity, adjusted mortality rates in nondiabetic (non-DM) patients were significantly higher on HD than on PD [age 18-44: RR (95% CI) = 1.24 (1.07, 1.44); age 45-64: RR = 1.13 (1.02, 1.25); age 65+: RR = 1.13 (1.05, 1.21)]. Among diabetic (DM) patients with no comorbidity, HD was associated with a higher risk of death among younger patients [age 18-44: RR = 1.22(1.05, 1.42)] and a lower risk of death among older patients [age 45-64: RR = 0.92 (0.85, 1.00); age 65+: RR = 0.86 (0.79, 0.93)]. Within the group of 220,247 (55%) patients with baseline comorbidity, adjusted mortality rates were not different between HD and PD among non-DM patients [age 18-44: RR = 1.19 (0.94, 1.50); age 45-64: RR = 1.01 (0.92, 1.11); age 65+: RR = 0.96 (0.91, 1.01)] and younger DM patients [age 18-44: RR = 1.10 (0.92, 1.32)], but were lower with HD among older DM patients with baseline comorbidity [age 45-64: RR = 0.82 (0.77, 0.87); age 65+: RR = 0.80 (0.76, 0.85)].

CONCLUSION

Valid mortality comparisons between HD and PD require patient stratification according to major risk factors known to interact with treatment modality. Survival differences between HD and PD are not constant, but vary substantially according to the underlying cause of ESRD, age, and level of baseline comorbidity. These results may help identify technical advances that will improve outcomes of patients on dialysis.

Establishment and maintenance of vascular access in incident hemodialysis patients: a prospective cost analysis

Despite the importance of hemodialysis vascular access, the cost of vascular access care has not been studied in detail. A prospective cost analysis was performed among incident hemodialysis patients to determine the cost of vascular access care overall and on the basis of access type. Detailed clinical and demographic information, as well as data on access type, was collected for all local incident hemodialysis patients between July 1, 1999, and November 1, 2001. A comprehensive measure of total vascular access costs, including surgery, radiology, hospitalization for access complications, physician costs, costs for management of outpatient bacteremia, and vascular access monitoring costs, was obtained. Costs are reported in 2002 Canadian dollars (1 CAN dollar = 0.69 US dollar). A total of 239 consecutive incident hemodialysis patients were identified, 49, 157, and 33 of whom were dialyzed exclusively with a catheter or had a native arteriovenous fistula or synthetic graft attempted, respectively. In year 1, 18.4% of all hospital admissions were for vascular access-related complications. The mean cost of all vascular access care in year 1 was 6890 CAN dollars(median 4020 dollars; interquartile range [IQR] 2440 dollars to 7540 dollars). The mean cost of access care per patient-year at risk for maintaining a catheter exclusively, attempting an arteriovenous fistula, or attempting a graft was 9180 dollars (median 3812 dollars; IQR 2250 dollars to 7762 dollars), 7989 dollars (median 4641 dollars ; IQR 3035 dollars to 8832 dollars), and 11,685 dollars (median 8152 dollars; IQR 3395 dollars to 12,908 dollars), respectively (P = 0.01). Vascular access care is responsible for a significant proportion of health care costs in the first year of hemodialysis. These results support clinical practice guidelines that recommend preferential placement of a native fistula.

Healing of Implanted Expanded Polytetrafluoroethylene Vascular Access Grafts with Different Internodal Distances: A Histologic Study in Dogs

OBJECTIVE

We assessed characteristics of healing, over time, of two types of expanded polytetrafluoroethylene grafts.

STUDY DESIGN

An experimental histological study in dogs.

METHODS

The graft types studied had the same internal diameter (5 mm) but different internodal distances. In one, the internodal distance was 60 microm in the external surface and 20 microm in the luminal surface. In the other, the internodal distance was 30 microm throughout the material. Sixteen grafts of each type were implanted between the femoral artery and vein in 16 dogs; explanted 1, 2, 4 or 12 weeks later; and examined histologically.

RESULTS

In both graft types, infiltrating-cell density and maximum cell-penetration depth increased significantly between 1 and 2 weeks after implantation, but no significant increases occurred after 2 weeks. The number of inflammatory cells peaked 1 week after implantation and decreased significantly by 2 weeks. Subsequently, there were no significant changes in inflammatory cell numbers, suggesting that the inflammatory phase was over by 2 weeks after implantation and the grafts had become attached to surrounding tissue. There were no significant differences between the two graft types in cell density, cell-penetration depth, or number of inflammatory cells at any assessment time.

CONCLUSION

Our results provide histologic support for guidelines recommending that synthetic vascular grafts for hemodialysis access should not be cannulated until 2 weeks after implantation. Since increasing the internodal distance to 60 microm in the external surface had no effect on graft healing, methods other than manipulation of internodal distance should be used in developing a graft suitable for early cannulation.

Inadequate Treatment of Cardiovascular Disease and Cardiovascular Disease Risk Factors in Dialysis Patients: A Commentary

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in patients with end-stage renal disease (ESRD). Despite its significant impact on health outcomes, which would imply a need for aggressive intervention, both CVD and CVD risk factors are inadequately treated in this patient population. The reasons for this inadequate treatment are unclear. This article reviews the contribution of traditional risk factors to the burden of CVD in ESRD patients, outlines the evidence regarding undertreatment of CVD and traditional CVD risk factors, and identifies potential factors that may be responsible for inadequate cardiovascular care in ESRD patients.

Incidence of arteriovenous thrombosis and the role of anticardiolipin antibodies in hemodialysis patients

INTRODUCTION

Fistula thrombosis in patients on maintenance hemodialysis is an important morbidity factor. Arterial or venous thrombotic events have been described as complications in patients on regular hemodialysis and positive titers of anticardiolipin antibodies (ACLA). This study was designed to evaluate the prevalence of ACLA in hemodialysis patients and it's relation to arteriovenous fistula (AVF) thrombosis.

METHODS

218 patients with AVF on maintenance hemodialysis were studied prospectively during a period of 14 months for any episode of AVF thrombosis (AVFT), after ACLA was assayed by ELISA in 171 ones. Other risk factors for thrombosis such as presence of diabetes, hypotension during dialysis, using of erythropoietin (rEpo), fistula site, gender, age, dialysis duration, and type of dialyser membrane were accessed.

RESULTS

56% of the patients had IgG ACLA = 10 GPL which was significantly correlated with dialysis duration (23.18 +/- 24.56 months in patients with ACLA = 10 GPL vs 37.73 +/- 36.35 months in patients with 20 = IgG ACLA < 40 GPL). Within 14 months follow up, 39 episodes of AVFT occurred in 34 patients (15.8%). Dialysis duration prior to start of study was 29.16 +/- 22.04 months. In our patients radiocephalic AVFs showed more thrombosis than brachiocephalic ones (23% vs 10%, p = 0.01 by Chi-square). Age more than 50 years old was a risk factor for AVFT (p = 0.034 by Chi-square). Also erythropoietin use (p = 0.011 by chi-square) and ultrafiltration more than 3 liters (average value of 14 months) were correlated with AVFT (p = 0.042 by Chi-square), but there wasn't any correlation between diabetes, presence of ACLA, hypotension during dialysis, gender, and dialysis membranes with AVFT. Ultimately, logistic regression analysis of factors associated with thrombosis was done and only fistula site (p = 0.015, O.R. = 2.87), and Eprex use (p = 0.031, O.R. = 4.05) showed significant correlation with AVFT.

CONCLUSION

Although incidence of anticardiolipin antibodies was high in our patients, we found no correlation between IgG ACLA and AVFT. Instead, we found that radiocephalic fistulas and Eprex injection were risk factors for AVFT.

K/DOQI Guidelines: What Should an Interventionalist Know?

The Kidney Disease Outcomes Quality Initiative (K/DOQI) is an evolving, literature-based set of practice guidelines designed to improve measurably the quality of life for dialysis patients. As is characteristic of guidelines, they do not change as rapidly as the literature. The K/DOQI guidelines are not meant as the definitive document and should be not treated as such. Although the guidelines are not perfect, everyone caring for chronic renal patients should be very familiar with the guidelines. It is perfectly acceptable to adopt approaches that differ from the guidelines as long as they are supported by literature. An attempt is made in this article to review the aspects of the guidelines most pertinent to the interventionalist and outline deviations from the guidelines that are supported by literature.

The effect of dialysis dose and membrane flux on nutritional parameters in hemodialysis patients: Results of the HEMO Study

BACKGROUND

The effect of standard or high dialysis dose and low or high dialysis flux on nutritional status was ascertained in 1846 maintenance hemodialysis patients enrolled in the HEMO Study.

METHODS

Serum albumin levels, equilibrated protein catabolic rate, and postdialysis weight were obtained monthly, while adjusted protein and energy intake, self-reported appetite assessment, upper arm circumference, and calf circumference were obtained yearly. To account for patient attrition due to death or transfer, three statistical models were used to test the effects of the study interventions on longitudinal changes in nutritional parameters.

RESULTS

During the first 3 years of follow-up, neither mean serum albumin levels, which declined by 0.21 g/dL, nor mean postdialysis weight, which declined by 2.7 kg, were significantly affected by either study intervention. Mean levels of all anthropometric measures declined during follow-up. For years 1, 2, and 3, the mean +/- SE declines in upper arm and calf circumferences were 0.35 +/- 0.16 cm (P= 0.031) and 0.31 +/- 0.13 (P= 0.015) cm less, respectively, in the high flux compared to the low flux group. Appetite scores and mean equilibrated protein catabolic rate also declined in all randomized groups; however, the average decline in equilibrated protein catabolic rate during years 1, 2, and 3 was 0.019 +/- 0.007 g/kg/day less in the high dose than the standard dose group (P= 0.007). There was no significant change in either mean energy or protein intake from diet records over time, and neither parameter was affected by the study interventions.

CONCLUSION

Although the dose and flux interventions may subtly influence certain nutritional parameters, neither intervention prevented deterioration in nutritional status over time.

Long-term survival of arteriovenous fistulas in home hemodialysis patients

BACKGROUND

We report the outcome of arteriovenous (AV) fistulas created and managed by a multidisciplinary team in patients on hemodialysis (HD) over 20 years.

METHODS

We analyzed 432 AV fistulas in 301 home HD patients (12% diabetic; median age 47 years) followed for up to 161 months. Observed end points were spontaneous or surgical AV fistula closure, or construction of a new vascular anastomosis. Survival was analyzed for first and second AV fistulas and predictors of outcome for first AV fistulas.

RESULTS

One vascular surgeon constructed 58% of AV fistulas. Three hundred sixty-seven AV fistulas were in the forearm, 64 at or above the elbow, and 1 in the thigh. Four hundred fourteen AV fistulas used in situ vessels, and 18 were autografts. Two hundred thirty-one anastomoses were side-to-side. Only five grafts were placed during this time. There were 131 second and subsequent AV fistulas in 76 patients, 79 (60%) of which required primary construction, and 52 used arterialized vessels from a previous AV fistula. The median time from formation to use for first and second AV fistula, respectively, was 2.39 (SE 0.35) and 3.2 (SE 1.9) months. Assisted survival from first use for first AV fistula was 90% at 1 year, 66% at 5 years, 84% at 1 year, and 72% at 2 years for second AV fistula. AV fistula survival from creation was superior for side-to-side anastomoses (P < 0.0001) and in men (P= 0.05).

CONCLUSION

A multidisciplinary approach has been successful in providing durable AV fistulas for home HD for >95% of consecutive patients entering our program.

The association of initial hemodialysis access type with mortality outcomes in elderly Medicare ESRD patients

BACKGROUND

Dialysis access is critical for therapy delivery. Few studies have linked type of dialysis access to patient survival in the elderly population.

METHODS

We included 1995 to 1997 incidence Medicare hemodialysis patients (N = 66,595) who were 67 years and older at dialysis therapy initiation. Medicare Physician/Supplier claims were used to determine initial access type: simple fistula, autologous vein graft, synthetic graft, and hemodialysis catheter. We used International Classification of Diseases, Ninth Revision, Clinical Modification, codes to determine vascular access placement for renal failure. A Cox regression analysis assessed risk for death within 1 year, with explanatory variables of incidence year, age, sex, race, diabetes, initial access type, body mass index, days from first access placement date to initial dialysis date, and serum albumin, creatinine, and blood urea nitrogen levels.

RESULTS

One-year crude death rates were 24.9%, 27.2%, 28.1%, and 41.5% for patients with simple fistulae, autologous vein grafts, synthetic grafts, and hemodialysis catheters, respectively. Patients with simple fistulae (the reference) had the lowest (P < 0.0001) likelihood of death compared with those with synthetic grafts (hazard ratio [HR], 1.160; 95% confidence interval [CI], 1.084 to 1.241) or catheters (HR, 1.696; 95% CI, 1.593 to 1.806). No difference (P > 0.09) in mortality risk was detected between simple fistulae and autologous vein grafts or between autologous vein grafts and synthetic grafts.

CONCLUSION

In the US Medicare dialysis population, type of initial hemodialysis access was associated with 1-year mortality. Mortality risks were (in ascending order) fistulae, grafts, and catheters.

End-stage renal disease and dialysis in hereditary amyloidosis TTR V30M: presentation, survival and prognostic factors

Classical familial amyloid polyneuropathy may have a course with progressive renal impairment. We studied 62 patients (24 males, 38 females) with FAP, transthyretin variant V30M, and end-stage renal disease (ESRD) treated with hemodialysis, all referred to a single center over a period of 11 years. Clinical course, morbidity and survival after dialysis were analyzed. Patient's mean age at first dialysis was 51.5 +/- 10.7 years, and mean duration of neuropathy was 10.2 +/- 3.8 years. The most frequent form of presentation of FAP nephropathy was nephrotic proteinuria with renal dysfunction. In the year prior to dialysis, renal function declined rapidly, and fluid overload was the main indication to initiate treatment. The presence of decubitus ulcers, significant disability, venous catheter for definitive vascular access for long-term treatment, and permanent bladder catheter, were related to death during the first year of dialysis. The mean duration of renal replacement therapy was 21 months, with a 54.5% one year, and 38.4% two year treatment survival. However, when the duration of neurological symptoms at first dialysis exceeded 10 years, survival was significantly lower. Infections, (41% were decubitus ulcers with sepsis) were the cause of early, as well as late mortality. Early creation of vascular access for hemodialysis, surveillance of skin wounds, and intervention on neurogenic bladder are essential to improve the prognosis of ESRD in FAP.

Protein homeostasis in chronic hemodialysis patients

PURPOSE OF REVIEW

Nutritional status is an important predictor of clinical outcome in chronic hemodialysis patients, as uremic malnutrition is strongly associated with an increased risk of death and hospitalization events. Decreased muscle mass is the most significant predictor of morbidity and mortality in these patients. Several factors that influence protein metabolism predispose chronic hemodialysis patients to increased catabolism and the loss of lean body mass. The purpose of this review is to discuss recent advances in the understanding of abnormalities in protein homeostasis in chronic hemodialysis patients.

RECENT FINDINGS

It has long been suspected that the hemodialysis procedure is a net catabolic event. Recent studies have indeed shown that the hemodialysis procedure induces a net protein catabolic state at the whole-body level as well as in skeletal muscle. There is evidence to suggest that these undesirable effects are caused by decreased protein synthesis and increased proteolysis. The provision of nutrients, either in the form of intradialytic parenteral nutrition or oral feeding during hemodialysis, can adequately compensate the catabolic effects of the hemodialysis procedure. Whereas the mechanisms of these effects have not been studied in detail, changes in extracellular amino acid concentrations and certain anabolic hormones such as insulin are important mediators of these actions.

SUMMARY

There is now indisputable evidence to suggest that the hemodialysis procedure leads to a highly catabolic state. Despite this, chronic hemodialysis patients can still achieve anabolism when given adequate protein supplementation to meet the metabolic requirements of hemodialysis, and when adequate insulin is present.

Re-endothelialization of punctured ePTFE graft: an in vitro study under pulsed perfusion conditions

BACKGROUND

When used as arteriovenous (AV) shunts for haemodialysis, small diameter expanded polytetrafluoroethylene (ePTFE) grafts have a high failure rate in vivo. Attempts to improve graft patency are various, and focus on either improvement of implantation techniques or graft tissue engineering. The tissue engineering approach attempts to reproduce in grafts the properties of pristine vasculature. As shown in previous experiments, it is possible to grow on ePTFE grafts under shear stress in vitro an autologous endothelial cell layer, which will withstand physiological stress under in vivo conditions of blood flow. The aim of this study was to investigate in an in vitro model the regenerative potency of a tissue-engineered prosthetic vascular graft after repeated cannulation with a haemodialysis cannula.

METHODS

Pig endothelial cells were harvested from an external jugular vein. Following processing of the endothelial cells, seven ePTFE grafts were coated with an inner cell layer and were kept under pulsed perfusion. Each graft was then cannulated three times with a standard shunt needle. The endothelium was then left to regenerate for a maximum of 48 h. The grafts were stained with haematoxylin/eosin before histological study.

RESULTS

All grafts were endothelialized over the puncture sites within 48 h. Histological analysis revealed a confluent endothelial cell lining at each puncture site. Cell morphology and cell pattern over puncture sites were not different from randomly picked locations over the graft lumen.

CONCLUSION

Our results underline the potential of endothelial tissue engineering in vascular shunt surgery. Vascular bio-hybrids that have the properties of pristine vascular endothelium may be a key step forward in maintaining angio-access in patients who require haemodialysis.

Durability and cumulative functional patency of transposed and nontransposed arteriovenous fistulas

OBJECTIVES

Preoperative duplex scanning of arm and forearm veins has increased the creation of autogenous arteriovenous (AV) fistulas. However, the cumulative functional patency and durability of transposed AV fistulas (TAVF) compared with nontransposed AV fistulas (AVF) and prosthetic bridging grafts (AVG) remains ill-defined.

METHODS

From January 1998 to December 2002, 245 dialysis access procedures were performed at University Hospital and the Veteran Affairs Medical Center in New Jersey. Follow-up data were available for 125 procedures (TAVF, n = 42; AVF, n = 30; AVG, n = 53) performed in 97 patients. All access procedures were planned on the basis of preoperative duplex scans of arm and forearm veins. Functional patency was defined as ability to cannulate and hemodialyze patients successfully. Primary and secondary cumulative functional patency of TAVFs, AVFs, and AVGs was determined with life table analysis, and differences were analyzed with the log-rank test. Differences in revision rates, including thrombolysis, thrombectomies, and operative revisions, were determined with the Fisher exact t test.

RESULTS

Mean follow-up was 18 months (range, 4-24 months). For TAVFs, AVFs, and AVGs, primary functional patency rate at 1 year was 76.2%, 53.3%, and 47.2%, respectively, and at 2 years was 67.7%, 34.4%, and 25.5%, respectively. Similarly, secondary functional patency rate at 1 year was 83.2%, 66.7%, and 58.5%, respectively, and at 2 years was 74.6%, 56.2%, and 40.2%, respectively. Primary and secondary functional patency rates for TAVFs were superior to those for AVGs at 1 and 2 years (P <.001). AVFs had superior secondary functional patency rate at 2 years, compared with AVGs (P <.05), and TAVFs had superior primary and secondary patency rates at 2 years, compared with AVFs (P <.05). AVGs required significantly more revisions than did TAVFs (28.5% vs 54.7%; P <.001) or AVFs (36.7% vs 54.7%; P <.05).

CONCLUSIONS

Preoperative duplex scanning of upper arm and forearm veins facilitated successful creation of all types of autogenous fistulas at our institution. TAVF cumulative functional patency rates were superior compared with AVGs and AVFs. Furthermore, TAVFs and AVFs were more durable and required fewer revisions than did AVGs. When preoperative duplex criteria indicate that TAVFs can be performed, they should be the initial access of choice, because of their superior long-term patency and durability.

Hospitalization in the first year of renal replacement therapy for end-stage renal disease

BACKGROUND

The requirement for hospitalization of patients on dialysis is likely to be a surrogate marker of age and comorbid diseases. It may also reflect the level of care delivered, and substantially increases the cost of this expensive therapy.

AIM

To identify the factors most strongly associated with hospitalization.

DESIGN

Prospective population study.

METHODS

Data were recorded for all patients starting RRT in Scotland over one year, including the reasons for and duration of, each hospital admission during the first year of RRT. Factors most strongly associated with hospitalization were determined by Poisson regression analysis.

RESULTS

Overall, 526 patients were admitted to hospital on 1668 occasions (median 3, IQR 1-4) for 13384 days (median 13, IQR 4-35). Formation of vascular access for haemodialysis (HD) was the most frequent reason for admission, followed by infections. Age, comorbidity, mode of presentation for RRT and primary renal diagnosis were all significantly associated with prolonged hospitalization. Attainment of UK Renal Association standards for urea reduction ratio and serum albumin concentration, and vascular access in the form of arterio-venous fistulae were associated with less hospitalization in patients treated with HD by 90 days.

DISCUSSION

Patients in their first year of RRT have a high requirement for in-patient care, 8.6% of patient treatment days being spent in hospital. Vascular access formation, failure and complications account for a large proportion of this. Age and comorbidity prolong the time spent in hospital. As the RRT population continues to increase, with older patients and those with greater comorbidity, in-patient facilities must also expand.

Regular Monitoring of Access Flow Compared with Monitoring of Venous Pressure Fails to Improve Graft Survival

ABSTRACT. Regular vascular access blood flow (Qa) surveillance is recommended to detect graft stenosis; however, there is little evidence that monitoring and correcting with angioplasty improves graft survival. This blinded, randomized, controlled trial of 112 patients studied time to graft thrombosis and graft loss, comparing monthly Qa plus standard surveillance (dynamic venous pressure and physical examination) (treatment group) to standard surveillance alone (control group). Only the treatment group was referred for angiogram if Qa <650 ml/min or a 20% decrease in Qa from baseline. Percutaneous angioplasty was performed for stenosis >50%. The rate of graft thrombosis per patient-year at risk was 0.41 and 0.51 in the control and treatment groups, respectively. Fifty-one interventions (0.93/patient-years at risk) were performed in the treatment groupversus31 interventions (0.61/patient-years at risk) in the control group. There was no difference in time to graft loss (P= 0.890). In a multivariate analysis, aspirin (ASA) therapy at baseline was associated with an 84% reduction in risk of graft thrombosis (odds ratio [OR], 0.14;P= 0.002). Higher baseline Qa (OR, 0.84;P= 0.05) and longer interval since graft insertion (OR, 0.97;P= 0.07) were associated with a decrease in graft thrombosis. Results reveal that graft surveillance that uses Qa increases the detection of stenosis, compared with standard surveillance; however, intervention with angioplasty does not improve the time to graft thrombosis or time to graft loss. E-mail: louise.moist@lhsc.on.ca

Hypercoagulable states and antithrombotic strategies in recurrent vascular access site thrombosis

Vascular access site thrombosis is a major cause of morbidity in patients receiving hemodialysis. The role of hypercoagulable states in recurrent vascular access site thrombosis remains poorly understood. Data are limited regarding systemic anticoagulation to improve access graft patency, because of concern about hemorrhagic complications. We determined the prevalence of hypercoagulable states and clinical outcome (thrombotic and hemorrhagic) after initiation of antithrombotic therapy in a series of patients with recurrent vascular access site thrombosis. We evaluated 31 patients who had sustained 119 thrombotic events that resulted in vascular access graft failure during the year before evaluation. Sixty-eight percent of patients tested had elevated concentrations of antibody to anticardiolipin or topical bovine thrombin, and 18% of patients tested had heparin-induced antibodies. More than 90% of patients had elevated factor VIII concentration, 62% had elevated fibrinogen concentrations, and 42% had elevated C-reactive protein concentrations. Twenty-nine patients were given antithrombotic therapy: 13 with warfarin sodium, 12 with unfractionated heparin (UFH), and 11 with low molecular weight heparin (LMWH). Seven patients received more than one antithrombotic agent, sequentially. Nineteen patients have had no thrombotic events since beginning antithrombotic therapy (10 with warfarin, 3 with UFH, 6 with LMWH). Mean follow-up was 8.6 months (median, 7 months). Eight patients sustained 10 bleeding complications (5 with warfarin, 3 with UFH, and 2 with LMWH). In conclusion, hypercoagulable states are common in patients with recurrent vascular access site thrombosis. Antithrombotic therapy may increase vascular access graft patency, but is associated with significant risk for hemorrhage. Prospective studies are needed to evaluate the role and safety of antithrombotic agents in improving vascular access graft patency.