Canadian Hemodialysis Morbidity Study

Infective endocarditis in dialysis patients: new challenges and old

BACKGROUND

Since the 1960s chronic hemodialysis (HD) has been recognized as a risk factor for the development of infective endocarditis (IE). Historically, it has been particularly associated with vascular access via dual lumen catheters. We wished to examine the risk factors for, and consequences of, IE in the modern dialysis era.

METHODS

Cases of IE (using the Duke criteria) at St. Thomas' Hospital (1980 to 1995), Guy's (1995 to 2002), and King's College Hospitals (1996 to 2002) were reviewed.

RESULTS

Twenty-eight patients were identified as having developed IE (30 episodes of IE). Twenty-seven patients were on long-term HD and one patient was on peritoneal dialysis (PD). Mean age was 54.1 years, and mean duration of HD prior to IE was 46.3 months. Eight patients were diabetic. Primary HD hemoaccess was an arteriovenous fistula (AVF) in 41.3%, a dual-lumen tunneled catheter (DLTC) in 37.9%, a polytetrafluoroethylene (PTFE) graft in 10.3%, and a dual- lumen non-tunneled catheter (DLNTC) in 4%. The presumed source of sepsis was directly related to hemoaccess in 25 HD patients: DLTC in 48%; AVF in 32%; PTFE in 12%; and DLNTC in 4%. Staphylococcus aureus[including methicillin resistant Staphylococcus aureus (MRSA)] was present in 63.3%. The mitral valve was affected in 41.4% of patients, aortic valve in 37.9% of patients, and both valves were affected in 17.2% of patients. Of note, 51.7% of patients had an abnormal valve before the episode of IE. In 15 cases surgery was undertaken. Fourteen patients survived to discharge, and 12 survived for 30 days. In 15 cases antibiotic treatment alone was employed; in this case, eight patients died and seven survived to discharge.

CONCLUSION

This is the largest reported confirmed IE series in dialysis patients. Infective endocarditis in HD patients remains a challenging problem-although hemoaccess via dual-lumen catheters remains a significant risk, many cases developed in patients with AVFs and this group suffered the greatest mortality. An abnormal valve (frequently calcified) was another risk factor; because valve calcification is now common after 5 years on dialysis, more effort in preventing this avoidable form of ectopic calcification may reduce the risk of developing IE.

Vascular access outcomes using the transposed basilic vein arteriovenous fistula

BACKGROUND

Although the transposed basilic vein arteriovenous fistula (TBAVF) is increasingly performed for hemodialysis vascular access in patients lacking adequate superficial veins, little is known about the long-term patency or risk factors for failure.

METHODS

A retrospective analysis was conducted for 99 patients who had a TBAVF created between April 1997 and October 2001. Primary outcomes were unassisted and assisted patency rates and primary failure rates.

RESULTS

This was the first access procedure in 46% of patients, mean age was 55 years, and 46% were men. Unassisted and assisted patency rates were 47% and 64% at 1 year and 41% and 58% at 2 years, respectively. Primary access failure occurred in 23% of cases. Unassisted access patency was significantly worse in patients with a previous access (relative risk [RR], 2.04; confidence interval [CI], 1.09 to 3.85; P = 0.03) or an ipsilateral central venous catheter (RR, 2.92; CI, 1.34 to 6.38; P < 0.01). Primary access failure was affected by older age (RR, 2.0; CI, 1.20 to 3.38; P < 0.01), obesity (RR, 7.1; CI, 1.65 to 30.1; P < 0.05), and a previous vascular access (RR, 6.4; CI, 1.49 to 27.6; P = 0.01). Steal syndrome requiring intervention occurred in 5% of cases.

CONCLUSION

In summary, the TBAVF provides a viable option for vascular access; however, certain patient characteristics seem to affect long-term patency and should be considered when exploring access options.

Lipoprotein(a) and prevalent cardiovascular disease in a dialysis population: The Choices for Healthy Outcomes in Caring for ESRD (CHOICE) study

BACKGROUND

Levels of lipoprotein(a) [Lp(a)], an atherogenic lipoprotein, are elevated in patients with end-stage renal disease and inversely related to the size of apolipoprotein(a) [apo(a)], a glycoprotein bound to Lp(a). We studied the association of Lp(a) level and apo(a) size with prevalent atherosclerotic cardiovascular disease (ASCVD) in 871 incident dialysis patients (261 blacks, 565 whites, 45 other).

METHODS

Lp(a) was measured by an apo(a) size-independent enzyme-linked immunoassay; and apo(a) size was measured by sodium dodecyl sulfate-agarose gel electrophoresis. Prevalent ASCVD, derived from medical records, was defined as coronary heart disease or cerebral or peripheral vascular disease. Adjustment variables included age, sex, race, dialysis modality, diabetes, serum creatinine level, albumin level, and low-density lipoprotein cholesterol level.

RESULTS

ASCVD prevalence was 58%. Median Lp(a) levels for those with compared with those without ASCVD were 38 versus 35 nmol/L for whites (P = 0.49) and 100 versus 74 nmol/L for blacks, respectively (P = 0.35). Lp(a) level was associated with ASCVD among those younger than 60 years (odds ratio [OR] for +1 interquartile range of Lp(a), 1.5; P = 0.02), but not among those 60 years and older (OR, 1.0; P = 0.82; P(interaction) by age, 0.08). ORs were 1.3 for all whites (P = 0.03) and 1.1 for all blacks (P = 0.87; P(interaction)by race = 0.53). ORs of ASCVD were 1.7 for whites younger than 60 years (P = 0.01) and 1.2 for blacks younger than 60 years (P = 0.77; P(interaction) by race = 0.42). No association between apo(a) isoform size and ASCVD was present.

CONCLUSION

In an incident dialysis cohort, Lp(a) level was associated with prevalent ASCVD among whites younger than 60 years, but not among blacks or those older than 60 years. Apo(a) isoform size was not associated with prevalent ASCVD. These data suggest that baseline ASCVD is unlikely to strongly confound the potential associations of Lp(a) level and prospectively ascertained ASCVD among incident dialysis patients.

Adapting the Charlson Comorbidity Index for use in patients with ESRD

BACKGROUND

Accurate prediction of survival for patients with end-stage renal disease (ESRD) and multiple comorbid conditions is difficult. In nondialysis patients, the Charlson Comorbidity Index has been used to adjust for comorbidity. The purpose of this study is to assess the validity of the Charlson index in incident dialysis patients and modify the index for use specifically in this patient population.

METHODS

Subjects included all incident hemodialysis and peritoneal dialysis patients starting dialysis therapy between July 1, 1999, and November 30, 2000. These 237 patients formed a cohort from which new integer weights for Charlson comorbidities were derived using Cox proportional hazards modeling. Performance of the original Charlson index and the new ESRD comorbidity index were compared using Kaplan-Meier survival curves, change in likelihood ratio, and the c statistic.

RESULTS

After multivariate analysis and conversion of hazard ratios to index weights, only 6 of the original 18 Charlson variables were assigned the same weight and 6 variables were assigned a weight higher than in the original Charlson index. Using Kaplan-Meier survival curves, we found that both the original Charlson index and the new ESRD comorbidity index were associated with and able to describe a wide range of survival. However, the new study-specific index had better validated performance, indicated by a greater change in the likelihood ratio test and higher c statistic.

CONCLUSION

This study indicates that the original Charlson index is a valid tool to assess comorbidity and predict survival in patients with ESRD. However, our modified ESRD comorbidity index had slightly better performance characteristics in this population.

Significance of platelet activation in vascular access survival of haemodialysis patients

BACKGROUND

Vascular access failure is the most common cause of morbidity and hospitalization in haemodialysis (HD) patients. Although there are reports that anti-platelet agents can prevent vascular access thrombosis, the relationship between platelet activation and vascular access failure is not clear. The aim of this study was to investigate the role of platelet activation in recurrent vascular access failure.

METHODS

The studied subjects were divided into three groups: group I included 23 HD patients with recurrent vascular access failure (native arteriovenous fistula <2 year survival or synthetic arteriovenous graft <1 year survival), group II included 15 HD patients with longer vascular access survival (>5 year survival) and group III included 10 healthy volunteers as controls. The expression of platelet activation markers (CD62P and fibrinogen receptor) and the numbers of platelet-derived microparticles were measured and compared between groups.

RESULTS

CD62P-positive platelets were significantly higher in group I than in both group II (7.3+/-3.7 vs 3.5+/-1.3%; P<0.0005) and group III (2.9+/-0.9%; P<0.00005). Fibrinogen receptor-positive (PAC-1-positive) platelets were also significantly higher in group I than in group II (2.2+/-2.1 vs 0.9+/-0.7%; P<0.01) and group III (0.8+/-0.6%; P<0.01).

CONCLUSIONS

A higher level of circulating activated platelets is associated with shorter survival of vascular access in HD patients. The higher level of circulating activated platelets may be a predictor of recurrent vascular access failure. The potential advantageous effects of anti-platelet therapy on this patient population warrant further investigation.

Outcomes research in dialysis

Worldwide, the number of patients with end stage renal disease (ESRD) and the number of ESRD patients receiving renal replacement therapy is growing. In the United States the number of patients enrolled in the Medicare-funded ESRD program has grown substantially, from approximately 10000 beneficiaries in 1973 to 340261 as of December 31, 1999. United States has the highest incidence ESRD of 317 per million population. Despite the magnitude of resources committed to the treatment of ESRD and the substantial improvements in the quality of dialysis therapy, these patients continue to experience significant mortality and morbidity, and reduced quality of life. Moreover, 50% of dialysis patients have 3 or more comorbid conditions, the mean number of hospital days per year is approximately 14 per patient, and self reported quality of life is far lower in dialysis patients than in general population. The most desirable interventions are those that specifically target measurable global outcomes such as mortality, morbidity, and health care costs. Nevertheless, patient outcomes that have shown links with these global outcomes may also be appropriate targets for intervention. This article will briefly review the available literature to discuss the role of important clinical indicators on dialysis outcomes and their impact on continuing care of ESRD population.

Overcoming barriers to arteriovenous fistula creation and use

National guidelines advocate the placement of arteriovenous fistulas (AVFs) as the preferred vascular access for hemodialysis (HD) patients because of their low complication rate, lower costs, and prolonged patency, once matured. The current Dialysis Outcomes Quality Initiative (DOQI) guidelines aim for an AVF incidence of 50% and a 40% prevalence in the United States. Although patients currently starting dialysis do so at an increasingly older age and with more comorbidity, they should be given every opportunity to receive an AVF. Meeting this challenge is facilitated by a multidisciplinary approach with early referral to the nephrologist in the predialysis period for access planning. Key components of a vascular access program may include the coordination by a dedicated access coordinator and outcome tracking via a prospective database. Preoperative vessel evaluation and careful selection of an appropriate surgical site, along with an experienced surgeon, improve surgical outcomes. Transposed brachiobasilic or other tertiary fistulas should be offered to patients who cannot receive a native radiocephalic or brachiocephalic fistula. The ability to routinely monitor and salvage failing AVFs is important to achieving successful AVF outcomes. Standardized definitions of AVF outcomes are important to allow individual centers and continuous quality assurance (CQA) programs to track and benchmark their outcomes against local and national standards to help them meet recommended targets.

Using cuffed and tunnelled central venous catheters as permanent vascular access for hemodialysis: a prospective study

BACKGROUND

Adequate care of a hemodialysis patient requires constant attention to the need to maintain vascular access (VA) patency. VA complications are the main cause of hospitalization in hemodialysis patients. The native arteriovenous fistula (NAVF), synthetic arteriovenous grafts fistula (GAVF) and silastic cuffed central venous catheters (CVCs) are used for permanent vascular access (PVA). CVCs are primary the method of choice for temporary access. But using this access modality is increasing more and more for PVA in elderly hemodialysis patients and when other PVA is not possible. The primary aim of this study is to investigate survivals and complications of the CVCs used for long-term VA.

METHODS

We prospectively looked at 92 CVCs (Medcomp Ash Split Cath, 14 FR x 28 cm (Little, M.A.; O'Riordan, A.; Lucey, B.; Farrell, M.; Lee, M.; Conlon, P.J.; Walshe, J.J. A prospective study of complications associated with cuffed, tunnelled hemodialysis catheters. Nephrol. Dial. Transplant. 2001, 16 (11), 2194-2200) with Dacron cuff) inserted in 85 (50 females, 35 males) chronic hemodialysis patients (the mean age: 56.6 +/- 14.1 years) from July 1999 to January 2002. The overall survival and complications were followed up. Furthermore, the patients were evaluated for demographic and clinical characteristics. Data were analysed by chi-square, Wilcoxon rank and Kaplan-Meier survival tests.

RESULTS

The median duration of CVC survival was 289 days (range: 10-720). Eleven (11.9%) CVCs were removed due to complications. In 79 (92.9%) patients, 1, in 5 (5.8%) patients, 2 and in 1 patient, 3 CVCs were inserted. Of the 85 patients, 56 have CVCs functioning. In addition, 27 (31.76%) patients have CVCs functioning for over 12 months, 17 (20%) patients have CVCs functioning for 6 months. The total incidence of CVC related infections was 0.82 episodes/1000 catheter days. Besides, thrombosis was occurred in 10 (10.8%) CVCs. The most frequent indications for CVC removal were patient death (69.4%), thrombosis (16.6%) and CVC-related infections (13.8%).

CONCLUSIONS

CVCs are primarily used for temporary access. But this study indicates that CVC may be a very useful alternative permanent vascular access for hemodialysis patients when other forms of vascular access are not available.

Thrombosis in end-stage renal disease

Although renal failure has classically been associated with a bleeding tendency, thrombotic events are common among patients with end-stage renal disease (ESRD). A variety of thrombosis-favoring hematologic alterations have been demonstrated in these patients. In addition, "nontraditional" risk factors for thrombosis, such as hyperhomocysteinemia, endothelial dysfunction, inflammation, and malnutrition, are present in a significant proportion of chronic dialysis patients. Hemodialysis (HD) vascular access thrombosis, ischemic heart disease, and renal allograft thrombosis are well-recognized complications in these patients. Deep venous thrombosis and pulmonary embolism are viewed as rare in chronic dialysis patients, but recent studies suggest that this perception should be reconsidered. Several ESRD treatment factors such as recombinant erythropoietin (EPO) administration, dialyzer bioincompatibility, and calcineurin inhibitor administration may have prothrombotic effects. In this article we review the pathogenesis and clinical manifestations of thrombosis in ESRD and evaluate the evidence that chronic renal failure or its management predisposes to thrombotic events.

Why is coronary heart disease of uraemic patients so frequent and so devastating?

On September 6, 2001, Professor Fernando Valderrabano (Hospital Gregorio Marañon, Madrid) died at the age of 59 years. He was a leading figure in Spanish nephrology, a full professor of Medicine/Nephrology at the University Complutense of Madrid, and an outstanding scientist who published more than 300 articles in medical journals. He was a very intelligent and cultured person, and a man of great style who enjoyed a wide range of hobbies and interests in addition to his medical work. All his colleagues and friends mourn his passing.

Albumin at the start of peritoneal dialysis predicts the development of peritonitis

BACKGROUND

Both peritonitis and serum albumin level are associated with morbidity and mortality in peritoneal dialysis (PD) patients. Severe cases of peritonitis result in hypoalbuminemia. However, it is not clear whether hypoalbuminemia predicts the development of peritonitis.

METHODS

We performed a retrospective analysis of a prospectively collected database from six centers in western Pennsylvania and West Virginia. Incident PD patients with a Charlson Comorbidity Index (CCI) score at the start of PD therapy and serum albumin level measured within 30 days of initiation were selected. Poisson regression was used to analyze predictors of peritonitis.

RESULTS

Three hundred ninety-three patients had a CCI score and serum albumin level measured at the start of PD therapy. Overall peritonitis rate was 0.65 episodes/dialysis-year. Significant univariate predictors were albumin level (rate ratio [RR], 0.79 per 1-g/dL [10-g/L] increase; 95% confidence interval [CI], 0.65 to 0.95; P = 0.015), male sex (P = 0.003), and being dialyzed in the Veterans Administration (RR, 1.97; 95% CI, 1.48 to 2.62; P < 0.001) or other center (RR, 1.68; 95% CI, 1.92 to 5.62; P < 0.001). Although CCI score correlated inversely with albumin level (r = -0.305; P < 0.001), CCI score was only marginally predictive of peritonitis (P = 0.068). In multivariate analysis, predictors were albumin level (RR, 0.74; 95% CI, 0.31 to 1.75; P = 0.002) and race (RR, 1.36; P = 0.024). Patients with an initial serum albumin level less than 2.9 g/dL (29 g/L) had a peritonitis rate of 1.5 episodes/dialysis-year compared with 0.6 episodes/dialysis-year for patients with an initial serum albumin level of 2.9 g/dL or greater (P < 0.001).

CONCLUSION

Hypoalbuminemia at the start of PD therapy is an independent predictor of subsequent peritonitis. Intervention studies to decrease peritonitis risk in this high-risk subset of patients are needed.

Management of heart failure and coronary artery disease in patients with chronic kidney disease

Cardiovascular disease (CVD) is a major contributor to the mortality and morbidity of patients who suffer from chronic kidney disease (CKD). Heart failure and ischemic heart disease (IHD) are both highly prevalent in this population. The diagnosis of myocardial dysfunction is usually based on echocardiography. As in the general population, systolic dysfunction is treated with a combination of diuretics, renin-angiotensin system blockade, and beta-receptor antagonists. Diastolic dysfunction is best managed by eliminating the cause. Non-invasive tests for coronary artery disease (CAD) may be less reliable in patients with renal disease compared with nonuremic patients. Medical therapy of IHD in this population is generally similar to that for other patient groups, but surgical revascularization appears to carry a higher risk of complications with poorer clinical outcomes. The choice of revascularization procedure (coronary artery bypass grafting versus percutaneous transluminal angioplasty) should be based on the specific coronary anatomy of a given patient as well as a consideration of other comorbid factors.

Isometric exercise increases the size of forearm veins in patients with chronic renal failure

OBJECTIVES

Delay in maturation or failure of maturation of Cimino-Brescia fistulae contributes to the significant vascular access-related morbidity of chronic hemodialysis patients. Increased size and capacitance of native veins before the formation of vascular access has been considered an important variable in the success rate of native fistulae. We evaluated whether a formal exercise program might alter the size of native veins.

METHODS

The effect of exercise on venous size was evaluated in 5 patients with severe chronic renal failure [glomerular filtration rate, 30.6 +/- 5.3 mL/min (mean +/- SD)]. Five male patients with a mean age of 57 +/- 9 years underwent a 6-week forearm exercise training program, involving nondominant arms, that included isometric hand-grip contractions to 25 to 35% of MVC lasting 40 to 120 seconds and repetitive squeezing of squash and racquet balls. Both the volume and intensity of exercise training was increased weekly based on strength measured by hand-grip dynamometer and on the patients' indicated level of comfort. Cephalic vessel size in both the nondominant (trained) and dominant (control) arms, with and without a tourniquet, were obtained using Doppler ultrasound before and after the 6-week exercise training program.

RESULTS

The size of the cephalic vein of the exercised arm increased significantly ( < 0.05) compared with the control arm when measured in both the absence (048 +/- 0.016 versus 0.024 +/- 0.023 cm ) and the presence of a tourniquet (0.056 +/- 0.022 versus 028 +/- 0.027 cm ).

CONCLUSIONS

These findings indicate that a simple, incremental resistance, exercise-training program can cause a significant increase in the size of the cephalic vein commonly used in the creation of an arteriovenous fistula. The increase in size and resultant probable increase in blood flow might accelerate the maturation of native arteriovenous fistulae, thereby lessening the morbidity associated with vascular access.

Alternative methods of anticoagulation for dialysis-dependent patients with heparin-induced thrombocytopenia

Dialysis patients who are continually exposed to heparin are at risk for heparin-induced thrombocytopenia (HIT). Heparin-induced antibodies have been reported to occur in 0-12% of hemodialysis (HD) patients. The diagnosis or suspicion of HIT in this patient population requires careful confirmation of the diagnosis and substitution of heparin with an alternate anticoagulant for dialysis. Alternate agents such as the direct thrombin inhibitors (hirudin and argatroban) are available, but careful dosing and monitoring of the anticoagulant effect are required. Despite careful dosing, hemorrhagic complications have occurred with these agents. Unfortunately there are limited options for treatment of hemorrhagic complications and no specific antidotes are available for the direct thrombin inhibitors. In this report the currently available alternatives to heparin for dialysis, including dosing and monitoring recommendations, are reviewed.

No Association between Hyperhomocysteinemia and Vascular Access Thrombosis in Chronic Hemodialysis

Purpose

Hyperhomocysteinemia, recognized as a risk factor for cardiovascular diseases, has also been related with controversy to vascular access thrombosis in hemodialysis. Our objective was to determine if such an association could be found in our hemodialysis population.

Methods

The survey was conducted in a cohort of 165 chronic hemodialysis patients. Their vascular access history was considered from hemodialysis initiation until November 1999, including the number of vascular accesses created (either native or synthetic fistulae), focussing on vascular access thrombotic events, and excluding primary vascular access dysfunction. Diabetes, hemoglobin, erythropoietin dose, anticoagulation, and methyltetrahydrofolate reductase (MTHFR) status were considered. Serum total homocysteine (tHcy) measures were sampled for all patients in June 1998 and repeated yearly. Patients had not been supplemented routinely with hydrosoluble vitamins until June 1998, after which all received DiaVite® (R&D Laboratories, CA, USA) daily.

Results

Median survival of native fistulae was significantly longer (81 months, 95%CI 35–127) than for synthetic fistulae (31 months, 95%CI 27–51). Median vascular access survival was reduced for diabetics vs non diabetics (28 vs 57 months) (P<0.05), whereas sex, age and smoking had no impact. No correlation was found between tHcy concentration and the number of vascular access thrombotic events; homozygotes for MTHFR had higher tHcy but no more vascular access thrombotic events. The 38 patients with a mean vascular access survival of less than 12 months (6±3 months) were compared to the 127 patients with a mean vascular access survival of ≥ 12 months (39±25 months) (P<0.05): no difference in their respective tHcy concentrations before and after DiaVite® introduction was found (31±13 and 20±8 vs 34±17 and 22±6 μmol/L), but the first group presented more numerous synthetic fistulae (p<0.0001), lower hemoglobin levels, and higher erythropoietin doses.

Conclusions

No significant association between hyperhomocysteinemia and vascular access thrombosis could be found in our population. DiaVite® introduction allowed a significant reduction in tHcy, but had no impact on vascular access survival, except for a slight but not significant reduction in the prevalence of vascular access thrombotic events during the year on DiaVite®. Potential benefits of approaches to reduce tHcy for vascular access time-life prolongation remain to be demonstrated.

Medical adjuvant treatment to increase patency of arteriovenous fistulae and grafts

BACKGROUND

End Stage Renal Failure (ESRF) patients often require either the formation of an arteriovenous (A-V) fistula or an A-V interposition prosthetic shunt for haemodialysis.

OBJECTIVES

To determine the effects of adjuvant drug treatment on the patency of fistulae and shunts in patients with ESRF undergoing haemodialysis by assessing the number of thrombotic episodes.

SEARCH STRATEGY

Publications describing (or potentially describing), randomised controlled trials of medical adjuvant treatment of patients with ESRF on haemodialysis via A-V fistula or interposition prosthetic A-V shunt, were sought through electronic searches of the Cochrane Peripheral Vascular Diseases Specialised Trials Register (last searched October 2002), and the Cochrane Central Register of Controlled Trials (CENTRAL) database (last searched Issue 3, 2002).

SELECTION CRITERIA

Randomised controlled trials of active drug versus placebo in patients with ESRF undergoing haemodialysis via an A-V fistula or prosthetic interposition A-V shunt.

DATA COLLECTION AND ANALYSIS

Two reviewers (ADS, PAR), independently assessed trial quality and three (ADS, XE, PAR) extracted data. Information on adverse events was collected from the trials. The outcome measure analysed was the long term fistula, or shunt patency rate.

MAIN RESULTS

The overall search identified three randomised controlled trials of aspirin versus placebo with a total number of 173 participants followed up to a maximum of 18 months. The aspirin dosage given was different in each of the trials (325 mg/once daily; 500 mg/once daily; and 160 mg/once daily). The overall result of the meta-analysis favoured treatment with aspirin (Odds Ratio (OR) 0.42, 95% Confidence Interval (CI) 0.20 to 0.86). The overall p-value for the three studies was 0.02. Three ticlopidine (a platelet aggregation inhibitor) versus placebo trials were also identified with a total number of 312 participants. All patients were followed up for one month, and the dose of ticlopidine given was the same for all three studies (250 mg/twice daily). The overall result of the meta-analysis also favoured treatment. (OR = 0.47, 95% CI 0.26 to 0.85). P-value for overall effect was 0.01. One trial in a parallel group design examined the effect of dipyridamole versus placebo, and dipyridamole plus aspirin versus placebo, and followed up patients for eighteen months. The overall result favoured treatment (OR 0.29, 95% CI 0.06 to 1.40) and (OR 0.77, CI 0.19 to 3.19) respectively.

REVIEWER'S CONCLUSIONS

The meta-analysis confirmed the beneficial effect of antiplatelet treatment as an adjuvant to increase the patency of A-V fistulae and shunts in the short term.

Normalized protein nitrogen appearance is correlated with hospitalization and mortality in hemodialysis patients with Kt/V greater than 1.20

OBJECTIVES

Normalized protein nitrogen appearance (nPNA), also known as protein catabolic rate (nPCR), reflects the daily protein intake in maintenance hemodialysis (MHD) patients. Several studies indicate that nPNA and Kt/V correlate with clinical outcome and also with each other. Thus, the relationship between low nPNA and poor outcome could be due to uremia, low Kt/V or due to reported mathematical coupling between nPNA and Kt/V. We therefore investigated whether nPNA is associated with outcome in patients who have adequate or high Kt/V.

DESIGN

Prospective cohort.

SETTINGS

Outpatient dialysis unit affiliated with a tertiary-care community medical center.

PATIENTS

From a pool of 135 MHD outpatients in one dialysis unit, 122 patients with a delivered, Kt/V(sp)>1.20, independent of their residual renal function, were evaluated. Patients (61 women, 61 men), aged from 23 to 89 years (53.4+/-14.0 years)(+/-SD), had been undergoing MHD for one month to 17 years.

INTERVENTION

Review of laboratory values and clinical outcome.

MAIN OUTCOME MEASURES

Twelve-month mortality and hospitalization.

RESULTS

Delivered Kt/V(sp) ranged from 1.23 to 2.71 (1.77+/-0.34), nPNA from 0.5 to 2.15 (1.13+/-0.29 g/kg/day), and serum albumin, from 1.9 to 4.6 (3.76+/-0.37 g/dL). During the 12-month follow-up, 55 patients were hospitalized overnight at least once; 12 patients died; 5 patients underwent renal transplantation, and 6 patients left the study. The nPNA and Kt/V(sp) did not correlate significantly (r=.09) except when analysis was limited to Kt/V values < 1.5 (r=.54). Serum nPNA and albumin were the only variables with statistically significant correlations with both mortality and 3 measures of hospitalization (H): total days of H (H(D)), total number of H (H(F)), and time to first H (H(T)). The case-mix adjusted correlations for serum albumin and nPNA versus total days (r(HD)) and frequency of H (r(HF)) were significant, and Cox analysis based on H(T) and time to death resulted in significant odds ratios for each standard deviation decrement for both serum albumin and nPNA. Serum total iron binding capacity (TIBC) and creatinine concentrations also correlated with some but not all outcome measures: lower serum concentrations of these values were each significantly associated with poor clinical outcomes.

CONCLUSIONS

Both nPNA and serum albumin predict prospective hospitalization and mortality in MHD patients with Kt/V > 1.20. Serum TIBC and creatinine concentrations appear to have association with some outcome measures as well. These data are consistent with the possibility that protein intake affects the clinical course even in the setting of an adequate to high hemodialysis dose. Studies based on randomized assignments to different protein intakes would be helpful to confirm these conclusions.

Hypertension as a determinant of survival for patients treated with home dialysis

BACKGROUND

Previous studies of the risks of hypertension for dialysis patients have yielded conflicting results. The aim of this study was to investigate, in a home dialysis population with low rates of diabetes and antihypertensive drug use, whether blood pressure (BP) was an independent risk factor for survival.

METHODS

The outcome of 168 consecutive patients (94 male, 88% Caucasian), aged 48 years (SD 16), who began home hemodialysis (HD; N = 124) or home continuous ambulatory peritoneal dialysis (CAPD; N = 44) between January 1, 1985 and December 31, 1994 were analyzed retrospectively. Only 4.7% of patients took antihypertensive drugs while on dialysis. The patients were followed to December 31, 1998 with the primary outcome being all-cause mortality. Censoring events were transplantation, transfer to another center and treatment modality change. The Cox proportional hazard model was used with baseline predictors.

RESULTS

Seventy-one patients died and the median overall survival was 4.2 years (5.6 on HD, 2.2 on CAPD, P < 0.0001). Mean BP at start of dialysis predicted survival on its own (P = 0.0009) and in the joint Cox model (P = 0.047). Other significant predictors in the joint model were age [10 year increase, relative hazard (RH) = 1.55, P = 0.0008], albumin (10 g/L decrease, RH = 2.05, P = 0.007), diabetes (RH = 3.42, P = 0.015) and peripheral vascular disease (RH = 2.19, P = 0.02) but not dialysis modality (RH = 1.63, P = 0.13). High and low mean blood pressure (BP) values at the start of dialysis were associated with the highest mortality.

CONCLUSIONS

Among the home dialysis patients, most of whom did not require antihypertensive drugs, hypertension was a risk factor for survival and patients with mid-range BP values survived the longest.

Prospective surveillance for primary bloodstream infections occurring in Canadian hemodialysis units

OBJECTIVE

Bloodstream infections are a major cause of morbidity and mortality in patients receiving long-term hemodialysis. We wanted to determine the incidence of hemodialysis-related bloodstream infections in Canadian centers participating in the Canadian Nosocomial Infection Surveillance Program.

METHODS

Prospective surveillance for hemodialysis-related bloodstream infections was performed in 11 centers during a 6-month period. Bloodstream infections were defined by published criteria. Hemodialysis denominators included the number of dialysis procedures, the number of patient-days on dialysis, and the frequencies of different types of vascular access.

RESULTS

There were 184 bloodstream infections in 133,158 dialysis procedures (1.4 per 1,000) and 316,953 patient-days (0.6 per 1,000). Hemodialysis access through arteriovenous (AV) fistulae was associated with the lowest risk for bloodstream infection (0.2 per 1,000 dialysis procedures). The relative risk for infection was 2.5 with AV graft access, 15.5 with cuffed and tunneled central venous catheter (CVC) access, and 22.5 with uncuffed CVC access (P < .001). There was marked variation among the 11 centers in the means of vascular access used for hemodialysis. Significant variation in infection rates was observed among the centers when controlling for types of access.

CONCLUSIONS

There was a hierarchy of risk of hemodialysis-related bloodstream infection according to type of vascular access. There was significant variation in the type of vascular access being used among the Canadian hemodialysis centers, and also variation in access-specific infection rates between centers.

Randomized trial of darbepoetin alfa for treatment of renal anemia at a reduced dose frequency compared with rHuEPO in dialysis patients

BACKGROUND

Darbepoetin alfa is a glycoprotein with a three-fold longer terminal half-life than recombinant human erythropoietin (rHuEPO). We aimed to determine whether darbepoetin alfa is as effective and well tolerated as rHuEPO for treating renal anemia in dialysis patients when administered at a reduced dose frequency.

METHODS

A total of 522 European and Australian hemodialysis and peritoneal dialysis patients receiving stable rHuEPO therapy by either the intravenous (IV) or subcutaneous (SC) route were randomized, open-label in a 1:2 ratio to continue rHuEPO or to receive an equivalent dose of darbepoetin alfa at a reduced dose frequency. Patients receiving rHuEPO once weekly changed to once every other week darbepoetin alfa, and those receiving rHuEPO two or three times weekly changed to once-weekly darbepoetin alfa. The doses of rHuEPO and darbepoetin alfa were titrated to maintain hemoglobin close to the patient's baseline level for up to 52 weeks. The primary endpoint was the change in hemoglobin between baseline and the evaluation period at weeks 25 to 32 of treatment.

RESULTS

The mean change in hemoglobin from baseline to the evaluation period was similar in the darbepoetin alfa (-0.03 g/dL; SE 0.11) and rHuEPO (-0.06 g/dL; SE 0.13) groups, and the difference between the two treatments was 0.03 g/dL (95% CI -0.16, 0.21). This was not a statistically significant or clinically relevant difference, despite the reduced frequency of darbepoetin alfa administration. At the end of the evaluation period, >/=95% of patients had their hemoglobin successfully maintained on their assigned dose frequency for darbepoetin alfa (once weekly and once every other week) and rHuEPO (once, twice and three times weekly). The safety profiles of darbepoetin alfa and rHuEPO were similar, and no antibodies to either treatment were detected.

CONCLUSIONS

Darbepoetin alfa maintains hemoglobin as effectively as rHuEPO, but with a reduced dose frequency.

Increasing arteriovenous fistulas in hemodialysis patients: problems and solutions

National guidelines promote increasing the prevalence of fistula use among hemodialysis patients. The prevalence of fistulas among hemodialysis patients reflects both national, regional, and local practice differences as well as patient-specific demographic and clinical factors. Increasing fistula prevalence requires increasing fistula placement, improving maturation of new fistulas, and enhancing long-term patency of mature fistulas for dialysis. Whether a patient receives a fistula depends on several factors: timing of referral for dialysis and vascular access, type of fistula placed, patient demographics, preference of the nephrologist, surgeon, and dialysis nurses, and vascular anatomy of the patient. Whether the placed fistula is useable for dialysis depends on additional factors, including adequacy of vessels, surgeon's experience, patient demographics, nursing skills, minimal acceptable dialysis blood flow, and attempts to revise immature fistulas. Whether a mature fistula achieves long-term patency depends on the ability to prevent and correct thrombosis. An optimal outcome is likely when there is (1) a multidisciplinary team approach to vascular access; (2) consensus about the goals among all interested parties (nephrologists, surgeons, radiologists, dialysis nurses, and patients); (3) early referral for placement of vascular access; (4) restriction of vascular access procedures to surgeons with demonstrable interest and experience; (5) routine, preoperative mapping of the patient's arteries and veins; (6) close, ongoing communication among the involved parties; and (7) prospective tracking of outcomes with continuous quality assessment. Implementing these measures is likely to increase the prevalence of fistulas in any given dialysis unit. However, differences among dialysis units are likely to persist because of differences in gender, race, and co-morbidity mix of the patient population.

Hemodialysis arteriovenous fistula maturity: US evaluation

PURPOSE

To compare various objective ultrasonographic (US) criteria for native arteriovenous fistula (AVF) maturation with subsequent fistula outcomes and clinical evaluation by experienced dialysis nurses.

MATERIALS AND METHODS

US fistula evaluation results were analyzed retrospectively in 69 patients within 4 months after AVF placement; adequacy for dialysis was known in 54. Measurements included minimum venous diameter and blood flow rate. Experienced dialysis nurses examined 30 fistulas clinically. Predictors of fistula adequacy were analyzed with univariate and multivariate logistic regression. Mean fistula diameters and blood flow rates were compared by using analysis of variance or unpaired Student t tests.

RESULTS

Fistula adequacy for dialysis doubled if the minimum venous diameter was 0.4 cm or greater (89% [24 of 27]) versus less than 0.4 cm (44% [12 of 27]; P <.001). Fistula adequacy for dialysis was nearly doubled if flow volume was 500 mL/min or greater (84% [26 of 31]) versus less than 500 mL/min (43% [nine of 21]; P =.002). Combining venous diameter and flow volume increased fistula adequacy predictive value: minimum venous diameter of 0.4 cm or greater and flow volume of 500 mL/min or greater (95% [19 of 20]) versus neither criterion met (33% [five of 15]; P =.002). Women were less likely to have an adequate fistula diameter of 0.4 cm or greater: 40% (12 of 30) of women versus 69% (27 of 39; P =.015) of men. No significant differences in blood flow or minimum venous diameter were found during 2-4 postoperative months. Experienced dialysis nurses' accuracy in predicting eventual fistula maturity was 80% (24 of 30).

CONCLUSION

US measurements of AVF at 2-4 months in patients undergoing hemodialysis are highly predictive of fistula maturation and adequacy for dialysis.

Comorbidities in patients with end-stage renal disease in developing countries

Patients with end-stage renal disease (ESRD) who are on renal replacement therapy (RRT) usually have a certain number of comorbid factors. Cardiovascular diseases are the most common comorbidities and the most common causes of mortality in ESRD patients. Noncardiovascular comorbid factors including nutrition also have impact on survival of ESRD patients on RRT. There are scarce data regarding comorbidity in developing countries. Available data have shown that hypertension, diabetes, and various cardiovascular disorders are the leading comorbidities. Improvement in outcome for ESRD patients would depend on improving quality in RRT as well as a better understanding and management of comorbid conditions.

Pitfalls in achieving the Dialysis Outcome Quality Initiative (DOQI) guidelines for hemodialysis access?

The Dialysis Outcome Quality Initiative (DOQI) mandates that 50% of permanent hemodialysis (HD) access be native arteriovenous fistulae (AVFs). Recent reports have shown that when these guidelines are followed, the percentage of new AVFs can exceed DOQI guidelines. From July 1998 to July 2001, 330 HD access procedures were performed in an academic tertiary care center. Patients were categorized into two groups. Group I followed DOQI guidelines and underwent history and physical examination; duplex vein mapping; use of basilic vein transposition; and a postoperative protocol to determine maturation and start needle access in a stepwise progression. Group II had history and physical examination and basilic vein transposition was not used. Patient data were retrospectively reviewed. Overall, 100 (31%) HD shunts were AVFs. Group I (42/183, 23%) had significantly less AVFs (p = 0.005) than group II (58/147, 39%). For first-time placement of HD access, there was no significant difference (p = 0.95) in the percentage of AVFs in group I (26/62, 42%) and group II (29/68, 43%). For patients with prior history of HD access, significantly less AVFs (p <0.001) were placed in group I (16/121, 13%) than in group II (29/79, 37%). Group I had significantly less first-time HDS (P = 0.03) than group II, 34% VS. 46%, respectively. AVF maturation for hemodialysis occurred in 79% of group I and 71% of group II (P = 0.52). There were no significant differences (P > 0.05) when comparing age, gender, and incidence of diabetes between the two groups. AVF formation based largely on duplex vein mapping in group I and lack of basilic vein transposition in group II contributed to the inability to achieve DOQI guidelines. Integration of knowledge and practice among vascular surgeons may help to avoid these pitfalls.

Low-intensity warfarin is ineffective for the prevention of PTFE graft failure in patients on hemodialysis: a randomized controlled trial

Polytetrafluoroethylene (PTFE) dialysis grafts in patients with end-stage renal disease (ESRD) are prone to thrombotic failure. The objective of this multicenter, randomized, double-blind, placebo-controlled clinical trial was to determine if warfarin reduces the risk of failure of PTFE dialysis grafts. Patients with ESRD and newly placed PTFE grafts were studied at community and academic dialysis centers in Southwestern Ontario. Patients were allocated to receive warfarin or matching placebo, with the warfarin administered to achieve a target INR of 1.4 to 1.9. Time to graft failure was the main outcome measure. A total of 107 patients (56 allocated to warfarin) were randomized. The time-to-event analysis revealed no significant difference in the likelihood of graft survival between the two groups (odds ratio, 1.76 in favor of placebo; 95% confidence interval, 0.72 to 4.34). Six major bleeds occurred in five patients allocated to warfarin compared with none in the patients who received placebo (P = 0.03). In conclusion, low-dose warfarin was associated with an excess of clinically important major bleeding in patients with ESRD enrolled in this study. Furthermore, low-intensity, monitored-dose warfarin does not appear to prolong PTFE graft survival.

A prospective study of hemodialysis access-related bacterial infections

The objective of this study was to describe hemodialysis vascular-access related infections that occurred in hemodialysis patients over an 18-month period. The study is a prospective descriptive analysis of incidence infection rates in a hemodialysis unit in a tertiary-care medical center. Prospective surveillance for hemodialysis vascular access-related infection was performed for all patients undergoing hemodialysis from November 1999 through April 2001 at King Fahd Hospital of King Faisal University, Al-Khobar, Saudi Arabia. The total number of dialysis sessions was calculated. The type of vascular access was noted. Cultures were obtained and all infections were recorded and infection rates were calculated. There were 9627 hemodialysis sessions (5437 via permanent fistulae or grafts, 2409 via temporary central catheters, and 1781 via permanent tunneled catheters) during the 18-month study period. We identified a total of 109 infections, for a rate of 11.32/1000 dialysis sessions (ds). Of the 109, 23 involved permanent fistulae or grafts (4.23/1000 ds); 18 involved permanent-tunneled central catheter infections (10.1/1000 ds); and 68 involved temporary-catheter infections (28.23/1000 ds). There were 38 bloodstream infections (3.95/1000 ds) and 34 episodes of clinical sepsis (3.53/1000 ds). Seventy-one vascular access infections without bacteremia were identified (7.38/1000 ds), including 16 permanent-fistulae or graft infections (2.94/1000 ds), 7 permanent-tunneled central catheter infections (3.93/1000 ds), and 48 temporary-catheter infections (19.92/1000 ds). Staphylococcal organisms were responsible for 77% of the infections, with Staphylococcus epidermidis being the strain most commonly implicated. Gram-negative organisms were responsible for 23% of the infections. In conclusion, infection rates were highest in hemodialysis patients with temporary vascular access, compared with rates in those with permanent arteriovenous fistulae and synthetic grafts. Most of the bacterial organisms isolated from the vascular access sites were gram-positive cocci, with S. epidermidis accounting for 50% of the organisms. The rate of infection with gram-negative bacilli was higher than in other reports. Our greater dependence on central venous catheters, due to local factors, coupled with the immune-compromising comorbid conditions of our patients, may be contributory to the pattern of infection reported. Delays in the creation of vascular grafts for hemodialysis access should be avoided.

Vascular access and increased risk of death among hemodialysis patients

BACKGROUND

Hemodialysis with a venous catheter increases the risk of infection. The extent to which venous catheters are associated with an increased risk of death among hemodialysis patients has not been extensively studied.

METHODS

We conducted a retrospective cohort study of 7497 prevalent hemodialysis patients to assess the association between dialysis with a venous catheter and risk of death due to all causes and to infection.

RESULTS

A tunneled cuffed catheter was used for access in 12% of the patients and non-cuffed, not tunneled catheter in 2%. Younger age (P = 0.0005), black race (P = 0.0022), female gender (P = 0.0004), short duration since starting dialysis (P = 0.0003) and impaired functional status (P = 0.0001) were independently associated with increased use of catheter access. The proportion of patients who died was higher among those who were dialyzed with a non-cuffed (16.8%) or cuffed (15.2%) catheter compared to those dialyzed with either a graft (9.1%) or a fistula (7.3%; P < 0.001). The proportion of deaths due to infection was higher among patients dialyzed with a catheter (3.4%) compared to those dialyzed with either a graft (1.2%) or a fistula (0.8%; P < 0.001). The adjusted odds ratio (95% CI) for all-cause and infection-related death among patients dialyzed with a catheter was 1.4 (1.1, 1.9) and 3.0 (1.4, 6.6), respectively, compared to those with an arteriovenous (AV) fistula.

CONCLUSION

Venous catheters are associated with an increased risk of all-cause and infection-related mortality among hemodialysis patients.

National profile of practice patterns for hemodialysis vascular access in the United States

The Centers for Medicare & Medicaid Service's (CMS), national End-Stage Renal Disease (ESRD) Clinical Performance Measures (CPM) Project is a data collection initiative to identify opportunities for improvement of care to adult, Medicare maintenance dialysis beneficiaries. This analysis of 1999 CPM data characterizes the profile of hemodialysis vascular access in the United States and identifies determinants of vascular access type 2 yr after the translation of vascular access clinical practice guideline statements into national CPMs. CPM data were collected during October to December 1999 and stratified by the 18 regional ESRD networks. Univariate and multivariable analyses were conducted to examine associations of access type with demographic, laboratory, and geographic variables. Multivariable logistic regression analyses were performed to identify independent variables associated with access type. A total of 8154 hemodialysis patients were sampled; 17% (n = 1399) were incident. Twenty-eight percent were dialyzed through an autologous arteriovenous fistula (AVF), 49% through a prosthetic graft (AVG), and 23% through a percutaneous catheter. Independent predictors of having a catheter for hemodialysis were female gender, white race, incident to hemodialysis status, and lower hemoglobin and serum albumin. For patients with a fistula or AVG, female gender (odds ration [OR], 2.46 [2.18 to 2.78]) and black race (OR, 1.70 [1.50 to 1.93]) were the strongest predictors of dialysis through an AVG. Other predictors of dialysis through an AVG were older age, increased body mass index (BMI), diabetes mellitus as the cause of ESRD, and lower serum albumin. Even in adjusted analyses, there was significant geographic variability with respect to hemodialysis access type. Despite translation of practice guidelines for hemodialysis vascular access into national CPMs, there is substantial geographic variability and gender and racial disparity in angioaccess allocation in the United States. Quality improvement strategies to improve the prevalence of fistulae should focus on selected regions and include physician education about their practice patterns and potential biases.

Delayed nephrologist referral and inadequate vascular access in patients with advanced chronic kidney failure

We sought to determine whether late referral to a nephrologist in patients with chronic renal failure influences the adequacy of vascular access for hemodialysis. We analyzed data describing all health care encounters for all Medicare and Medicaid patients with end-stage renal failure in New Jersey between January 1991 and June 1996. Patients were required to have been diagnosed with renal disease at least 1 year prior to onset of hemodialysis. In the resulting cohort of 2,398 incident hemodialysis patients, 35% had their first nephrologist consultation < or =90 days prior to initiation of dialysis. After controlling for demographic characteristics, socio-economic status and underlying renal disease, we found that patients who were referred to a nephrologist >90 days prior to onset of hemodialysis were 38% more likely to have undergone predialysis vascular access surgery than those who were referred to a nephrologist < or =90 days before dialysis [OR: 1.38; 95% CI (1.15; 1.64)]. Similarly, patients referred late were 42% more likely to require central venous access for hemodialysis compared to those seen by a nephrologist early [OR: 1.42; 95% CI (1.17; 1.71)]. Inadequate development of vascular access for renal replacement therapy in patients with late nephrologist referral unnecessarily contributes to the burden of disease experienced by this vulnerable patient population.

Extra-renal abscess in chronic hemodialysis patients

AIM

Infectious disease represents one of the major causes of morbidity and mortality in hemodialysis patients. Extra-renal abscess constitutes a specific form of infection. The aim of this study was to evaluate and analyze the clinical characteristics of extra-renal abscess in chronic hemodialysis patients.

METHODS

We retrospectively studied the extra-renal abscess among chronic hemodialysis patients in Chang Gung Memorial Hospital at Kaohsiung, Taiwan. The records of 2,168 chronic hemodialysis patients from October 1986 to January 2000, were studied. The clinical features were reviewed and analyzed.

RESULTS

Sixteen patients who were enrolled during the study period developed extra-renal abscess. Ten of them were male. The mean age was 59.2 +/- 11.8 years old. More than half of the patients had diabetes (53.6%, 9/16). The locations of extra-renal abscess in these patients were liver (8/16), lung (5/16), spleen (1/16), perianal region (1/16), psoas muscle (1/16), and prostate (1/16). One patient had concurrent liver and spleen abscesses. All patients presented with fever and chills. Laboratory studies revealed leukocytosis and thrombocytopenia in 2/3 of the patients. The patients were associated with malnutrition status with lower serum albumin level (2.94 +/- 0.55 gm/dL) and lower nPCR (normalized protein catabolism rate; 0.84 +/- 0.11 gm/Kg/day) comparing to the other hemodialysis patients (albumin: 4.05 +/- 0.47 gm/dL; nPCR: 1.14 +/- 0.31gm/kg/day). There was no significant difference in kt/V between the patients with (1.28 +/- 0.34) or without abscess formation (1.47 +/- 0.36). The major causative pathogen was Klebsiella pnewnoniae. Parenteral antibiotic treatment is sufficient to treat most of the diseases, except 2 patients who needed surgical intervention. Twelve patients recovered after 2-3 weeks of treatment.

CONCLUSIONS

The study indicated that extra-renal abscess is rare in chronic hemodialysis patients. The abscesses occurred mostly in liver. Diabetes mellitus and poor nutrition status were the important predisposing factors. Gram-negative bacilli, K. pneumoniae, were the major pathogen. Most of the patients responded to parenteral antibiotics and surgical draining.

Traditional cardiovascular disease risk factors in dialysis patients compared with the general population: the CHOICE Study

Although atherosclerotic cardiovascular disease (ASCVD) risk in end-stage renal disease (ESRD) is 5 to 30 times that of the general population, few data exist comparing ASCVD risk factors among new dialysis patients to the general population. This cross-sectional study of 1041 dialysis patients describes the prevalence of ASCVD risk factors at the beginning of ESRD compared with estimates of ASCVD risk factors in the adult US population derived from the Third National Health and Nutrition Examination (NHANES III). CHOICE Study participants had a high prevalence of diabetes (54%), hypertension (96%), left ventricular hypertrophy by electrocardiogram (EKG) criteria (22%), low physical activity (80%), hypertriglyceridemia (36%), and low HDL cholesterol (33%). CHOICE participants were more likely to be older, black, and male than NHANES III participants. After adjustment for age, race, gender, and ASCVD (defined as myocardial infarction, revascularization procedure, stroke, carotid endarterectomy, and amputation in CHOICE; and as myocardial infarction and stroke in NHANES III), the prevalence of diabetes, hypertension, left ventricular hypertrophy by EKG, low physical activity, low HDL cholesterol, and hypertriglyceridemia were still more common in CHOICE participants. Smoking, obesity, hypercholesterolemia, and high LDL cholesterol, however, were less common in CHOICE than NHANES III participants. The projected 5-yr ASCVD risk based on the Framingham Risk Equation among those older than 40 yr without ASCVD was higher in CHOICE Study participants (13%) than in the NHANES III participants (6%). In summary, many ASCVD risk factors are more prevalent in ESRD than in the general population and may explain some, but probably not all, of the increased ASCVD risk in ESRD.

Hemodialysis vascular access preferences and outcomes in the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND

Synthetic grafts have generally been found to exhibit lower survival rates and higher complication rates than native arteriovenous fistulae. We investigated whether survival of grafts relative to fistulae was better in facilities with a preference for grafts, hypothesizing that such facilities may place more grafts because grafts produced superior outcomes.

METHODS

The study was based on a national U.S. sample of 133 hemodialysis facilities participating in the Dialysis Outcomes and Practice Patterns Study (DOPPS), a prospective, observational study of dialysis treatment practices and outcomes. Vascular access preferences were ascertained from medical directors, nurse managers, and actual practice within each facility (% graft use among prevalent patients). Logistic regression was used to model the odds ratio (OR) of graft placement (vs. fistula) and Cox regression was used to model time from access creation to initial failure.

RESULTS

Grafts were preferred by 21% of medical directors and 40% of nurse managers. Patients in facilities in which the medical director or nurse manager expressed a preference for grafts were more than twice as likely to have a graft than a fistula (AOR = 2.3, P < 0.01; reference group = facilities that did not prefer grafts), suggesting that facility preferences influence the type of access created. Overall, grafts were more prevalent than fistulae in dialysis facilities, but displayed a higher relative risk of failure (RR 1.33, P < 0.0001). However, the risk of graft versus fistula failure did not vary by expressed preference of the medical director: the relative risk of graft versus fistula failure was 1.39 in facilities in which the medical director preferred grafts and 1.39 in facilities in which the medical director preferred fistulae. Moreover, the relative risk of graft versus fistula failure was 1.57 in facilities that used more than the median percentage of grafts and 1.19 in facilities that used less than the median percentage of grafts.

CONCLUSIONS

No evidence was found that graft outcomes are superior in facilities that prefer grafts to fistulae. The observed variation in vascular access practice patterns suggests opportunities for quality improvement if optimal practices can be defined.

Approach to vascular access for hemodialysis: experiences from the Republic of Macedonia

Eight thousand eight hundred and forty nine different vascular hemodialysis accesses were performed in the period from 1976 until 1999 at the Department of Nephrology, Skopje: 3,114 native arterial-venous fistula (AVF), 715 arterial-venous shunts (AVS), 4,964 temporary or permanent catheters (4,411/88.86% femoral, 410/8.26% subclavian, 143/2.88% jugular) and 56 PTFE vascular grafts. Femoral catheterization (4,312/86.86%) is the favoured solution if a temporary vascular dialysis access is taken into consideration. The most popular chronic dialysis angio-access in our country is native AVF (90.5% of 3,440 permanent dialytic vascular accesses). The tunneled subcutaneously positioned catheters as a permanent dialytic angio-access were present in 270 cases (7.9%): 99 in femoral veins (our original method), 123 in subclavian veins and 48 catheters in jugular veins. The synthetic vascular grafts-PTFE (polytetrafluoro-ethylene) represent only 1.6% of all dialysis angio-accesses. The number of preventive AVFs created in patients with preterminal end-stage renal disease eventually increased; from 14% in the eighties, 20.8% after 10 years and 31.50% in 1999. Most of the preventive AVFs are done in outpatients 71.8% in 1999. This year 44.4% of all chronic vascular access were created in the same way. We prefer femoral catheters for both temporary and permanent access because our results show that femoral catheterization has a lower rate of early complications when compared to the subclavian catheterization group; the rate of late complications (thrombosis, stenosis, infections) is lower or the same; infections in femoral catheterizations are less frequent, compared to subclavian and jugular ones. Our contributions in the field of vascular access surgery are the three original methods which are constantly used at the Department: 1. Combination of temporary (AVS) and permanent vascular access (AVF) using the same blood vessels, performed in one surgical act; 2. Tunneled femoral catheter as a permanent vascular access for hemodialysis (2 types: on the abdominal wall and on the infrainguinal region - thigh); 3. Reduction of hyper-flow in AVF without the operation of "banding", with ligation of the artery before arteriovenous anastomosis.

Adverse clinical outcomes associated with short stature at dialysis initiation: a report of the North American Pediatric Renal Transplant Cooperative Study

OBJECTIVE

We examined whether height less than the 1% for age (z score <-2.5) at dialysis initiation predicts adverse clinical outcomes for children with kidney failure.

DESIGN

National cohort study of children initiating dialysis, followed for a minimum of 1 month to a maximum of 8 years.

SETTING

Voluntary consortium of pediatric nephrology centers across the United States and Canada in the North American Pediatric Renal Transplant Cooperative Study.

PATIENTS

Two thousand three hundred six patients </=21 years old initiated on dialysis between 1992 and 2000. Outcome Measures. School attendance, transplant wait listing, hospitalization rates, and survival.

RESULTS

Although there were no differences in transplant wait listings, school-aged children with short stature were less likely to be attending school full-time than were their counterparts with more normal height, even if medically capable. Short-stature patients have significantly more hospital days per month of dialysis follow-up than those patients with better growth (mean: 1.92 vs 1.58; median: 0.73 vs 0.44 hospital days per month of follow-up). Cox proportional hazards regression analyses show that children with height <1% for age have a twofold higher risk of death than those with more normal height, even after controlling for patient age, race, gender, cause of end-stage renal disease, wait list status, and dialysis modality.

CONCLUSIONS

Poor growth during chronic renal insufficiency leading to short stature at dialysis initiation is a marker for a more complicated clinical course for children with kidney failure. Aggressive nutritional support and early referral to a nephrologist to optimize growth may improve long-term outcomes for children with chronic kidney disease.

Critical care issues in the patient with chronic renal failure

The metabolic abnormalities associated with chronic renal failure and complications of the dialysis procedure present unique challenges in critical care medicine. Understanding how renal failure impacts the development and management of cardiovascular disease, bleeding tendencies, infection, and malnutrition is necessary to provide optimal care for these patients. The recognition of ESRD as a state of chronic inflammation and increased oxidative stress ultimately should lead to more effective treatment approaches for several of the comorbid conditions common in this patient population.

Race-specific association of lipoprotein(a) with vascular access interventions in hemodialysis patients: the CHOICE Study

BACKGROUND

Elevated serum levels of lipoprotein(a) [Lp(a)] and low molecular weight apolipoprotein(a) [apo(a)] isoforms are associated with atherothrombotic disease in the general population and in patients with kidney failure. Lp(a) may be more atherothrombotic in whites than in blacks. Data on the relation of Lp(a) and apo(a) isoform size to hemodialysis vascular access complications are limited.

METHODS

We analyzed the intervention-free survival of the first arteriovenous (AV) access among 215 white and 112 black incident hemodialysis patients participating in the CHOICE Study, a national multicenter prospective cohort study.

RESULTS

Median levels of Lp(a) protein were higher among blacks than whites (81.0 versus 37.5 nmol/L; P < 0.001) and inversely correlated with apo(a) isoform size (r = -0.57; P < 0.001). The incidence rate of access interventions was much higher in synthetic grafts (N = 193) than native fistulae (N = 134; 1.0 vs. 0.5 interventions per access-year; P < 0.001) and in patients with kidney failure primarily due to diabetes mellitus (N = 161) than others (N = 166; 0.9 vs. 0.6; P < 0.01), but did not differ by race. Blacks in the highest race-specific Lp(a) quartile (>145 nmol/L) had a significantly higher incidence rate than other blacks (1.4 vs. 0.7; P = 0.04), whereas no association was found in whites. The association in blacks remained after adjustment for access type and other characteristics (relative hazard = 1.68; 95% confidence interval: 0.98 to 2.86). No association was found with apo(a) isoform size in either race.

CONCLUSIONS

Elevated Lp(a) may be a risk factor for arteriovenous access complications among black hemodialysis patients. Future studies should explore this possibility and be adequately powered to allow race-specific analyses.

Short- and long-term functional effects of percutaneous transluminal angioplasty in hemodialysis vascular access

The efficacy of percutaneous transluminal angioplasty (PTA) is usually expressed as the angiographic result. Access flow (Qa) measurements offer a means to quantify the functional effects. This study was performed to evaluate the short-term functional and angiographic effects of PTA and to determine the longevity of the functional effects during the follow-up period. Patients with an arteriovenous graft (AVG) or an arteriovenous fistula (AVF) who were eligible for PTA (Qa values of <600 ml/min) were included. Ultrasound-dilution Qa measurements were obtained shortly before PTA and periodically after PTA, beginning 1 wk after the procedure. The short-term effects were expressed as the increase in Qa and the reduction of stenosis. The long-term effects were expressed as patency and the decrease in Qa after PTA. Ninety-eight PTA procedures for 60 patients (65 AVG and 33 AVF) were analyzed. Qa improved from 371 +/- 17 to 674 +/- 30 ml/min for AVG and from 304 +/- 24 to 638 +/- 51 ml/min for AVF (both P < 0.0001). In 66% (AVG) and 50% (AVF) of cases, Qa increased to levels of >600 ml/min. The degree of stenosis decreased from 65 +/- 3 to 17 +/- 2% for AVG and from 72 +/- 5 to 23 +/- 7% for AVF (both P < 0.005). The reduction of stenosis was not correlated with DeltaQa (r(2) = 0.066). Six-month unassisted patency rates after PTA were 25% for AVG and 50% for AVF. The decreases in Qa were 3.7 +/- 0.8 ml/min per d for AVG and 1.8 +/- 0.9 ml/min per d for AVF. Qa values before PTA and DeltaQa were correlated with the subsequent decrease in Qa (P < 0.005). In conclusion, Qa increases after PTA but, in a substantial percentage of cases, not to levels of >600 ml/min. Qa values before PTA and the increase in Qa were correlated with long-term outcomes, whereas angiographic results were not. These data, combined with literature data, suggest that there is optimal timing for PTA.

Homocysteine and vascular access thrombosis in hemodialysis patients

BACKGROUND

Vascular access remains the Achilles' heel of successful hemodialysis, and thrombosis is the leading cause of vascular access failure. Hyperhomocystinemia is common in hemodialysis patients and is associated with venous and arterial thrombosis in patients without end-stage renal disease.

SUBJECTS AND METHODS

In the study, 65 hemodialysis patients with native arteriovenous fistula were included. Two groups of patients were defined: group A including 45 patients with their vascular access either never or only once thrombosed, and group B including 20 patients with two or more thromboses of their vascular access. We determined serum concentrations of total homocysteine (immunoassay, Abbott) in our patients.

RESULTS

In 63 (96.9%) patients, hyperhomocystinemia was presented. There was no statistically significant difference between group A and B regarding age, gender and duration of hemodialysis treatment. Total homocysteine concentrations were higher in group A (42.1 +/- 18.6 micromol/l) than in group B (36.1 +/- 18.1 micromol/l) patients but the difference was small and not statistically significant.

CONCLUSION

We found no significant differences in total homocysteine concentrations between group A (thrombosis non-prone) and group B (thrombosis prone) patients. Our results suggest that thrombosis of native arteriovenous fistulas may not be caused by hyperhomocystinemia in these patients.

Epidemiology of hemodialysis vascular access infections from longitudinal infection surveillance data: predicting the impact of NKF-DOQI clinical practice guidelines for vascular access

National Kidney Foundation-Dialysis Outcomes Quality Initiative (NKF-DOQI) Vascular Access Guidelines 29 (40% of prevalent patients should have a native fistula) and 30 (<10% use of catheters for chronic hemodialysis) are currently based on opinion, rather than published evidence. The impact of these guidelines on reducing vascular access infection rates is unknown and was tested using data from an outpatient prospective cohort analysis. Patients undergoing hemodialysis from January 1998 through December 2000 at six outpatient facilities in Idaho and Oregon were evaluated prospectively for vascular access infections. There were 111,383 dialysis sessions (DSs) with 471 infections identified (4.2 infections/1,000 DSs). The risk for infection relative to arteriovenous (AV) fistulae was highly dependent on type of access used: 2.2 (P = 0.002) for AV grafts, 13.6 (P < 0.0001) for tunneled catheters, and 32.6 (P < 0.0001) for temporary catheters. Based on incidence infection rates, the number of infections predicted to occur with implementation of guidelines 29 and 30 in this population was calculated, and the percentage of reduction in infection was determined. Following either guideline 29 or 30 alone would have predictably prevented 103 or 97 total infections (22% and 21% reduction) and 40 or 51 bloodstream infections (24% and 30% reduction), respectively. Following both guidelines simultaneously would have prevented 151 total infections (32% reduction) and 64 bloodstream infections (38% reduction). These epidemiological data firmly establish that a major risk for vascular access infections is the type of access used (temporary catheters > tunneled catheters > AV grafts > AV fistulae). Furthermore, they strongly support the role of these NKF-DOQI guidelines in preventing infectious complications attributed to vascular access.

Hemodialysis vascular access survival: upper-arm native arteriovenous fistula

Achieving Dialysis Outcomes Quality Initiative guidelines for native arteriovenous fistulae using the radiocephalic forearm fistula (lower-arm fistula [LAF]) is difficult. This study reports results using the upper-arm native arteriovenous fistula (UAF). From a prospective access database (1992 to 1998), this study was based on 204 patients (322 accesses). Average patient age was 56 +/- 1 years, 63% were men, and 47% had diabetes. A native fistula was the first access in 73% of patients (36%, LAFs; 37%, UAFs) and accounted for 48% of subsequent accesses (13%, LAFs; 35%, UAFs). Younger men were more likely to receive an LAF, but there was no demographic difference between patients receiving a UAF or arteriovenous graft (AVG). Both primary unassisted and cumulative access patencies were significantly better for UAFs than either LAFs or AVGs. For first accesses, cumulative access patency rates at 1, 3, and 5 years were 71%, 57%, and 57% for UAFs; 54%, 46%, and 36% for LAFs; and 54%, 28%, and 0% for AVGs (P < 0.01). Despite shorter access survival, AVGs required more total access procedures than either UAFs or LAFs (procedures per access: 2.5, 1.0, and 0.6 for AVGs, UAFs, and LAFs, respectively). When used, catheters were required for dialysis for a longer time for UAFs (median catheter days, 36, 53, and 56 for AVGs, LAFs, and UAFs, respectively; P < 0.05). Access flow rates were greater in UAFs (1,247 mL/min; n = 48; P < 0.01) than AVGs (851 mL/min; n = 30) or LAFs (938 mL/min; n = 31). There was no evidence that UAFs were banded or ligated for steal syndromes or heart failure more often than AVGs or LAFs. These results show that the UAF is a good alternative to an AVG for achieving Dialysis Outcomes Quality Initiative guidelines.

In vitro evaluation of hemolysis and sublethal blood trauma in a novel subcutaneous vascular access system for hemodialysis

Hemodialysis requires reliable frequent access to the patients' vasculature, with blood flow rates of > 300 ml/min. Currently in the U.S. market, there are three types of hemodialysis access systems: the native arteriovenous fistula, generally using 15G needles; the synthetic arteriovenous (AV) graft, also generally using 15G needles; and the percutaneous catheter. Some of the problems with current vascular access technologies include insufficient blood flow, blood trauma, thrombosis, infection, cardiac load, and venous stenosis. The LifeSite System (Vasca, Inc.) represents an alternative for vascular access, and consists of a subcutaneous valve and 12F cannula accessed by a standard 14G needle. The LifeSite valve is implanted in the upper torso with the cannula generally entering the right internal jugular vein. The purpose of this study was to compare the LifeSite System with two known vascular access systems: the 10F dialysis catheter (Tesio-Cath, MedComp) and the 15G A.V. Fistula Needle Set (JMS Co., Ltd.) with regard to blood damage produced by these devices in use. Mechanical hemolysis and sublethal blood trauma were evaluated by means of in vitro blood pumping through a circulating loop incorporating a hemodialysis vascular access system. Sublethal blood damage was examined by using a hemorheologic assay that included parameters such as erythrocyte mechanical fragility, plasma total protein and fibrinogen concentrations, and blood viscosity. The tests demonstrated that, at both studied flow rates of 300 ml/min and 450 ml/min, the LifeSite produced lower hemolysis and less sublethal damage to blood than either the Tesio-Cath catheter or the A.V. Fistula Needle Set.

Dialysis and nutrition practices in Korean hemodialysis centers

OBJECTIVE

Survey the dialysis practices and nutritional status-related patient characteristics.

DESIGN

Cross-sectional survey.

SETTING

Twenty-eight randomly selected Korean hemodialysis facilities.

METHODS

Medical record review of 140 randomly selected patients in 28 Korean dialysis facilities. The Student t test and chi-square tests were used to compare facility types and locations.

RESULTS

The mean number of dialysis treatments per week was 2.7 +/- 0.4. Mean dialysis treatment length was 253 +/- 27.5 minutes. Rural dialysis centers reported fewer treatments per week and shorter dialysis treatment times than did urban centers but, otherwise, there were few differences by either location (urban v rural) or by facility type (hospital affiliated v freestanding facility). The mean age of the patients surveyed by record review was 51 +/- 14 years, and 59% of the patients were men. The primary causes of end-stage renal disease were chronic glomerulonephritis, hypertension, and diabetes. Average vintage of dialysis was 53 +/- 46 months. Adequacy of dialysis was usually assessed by using clinical judgment; urea kinetic modeling and urea reduction ratios were used less frequently. Patients' mean body mass index was 20.7 +/- 2.3, which was at the lower end of the healthy range of 18.5 to 25, and most (93%) of their weights had been stable over the previous 6 months. Their mean serum albumin level was 4.0 +/- 0.4 g/dL. Forty-two percent of patients used iron supplements and 68% of them received erythropoietin treatment. However, their mean hematocrit levels were only 25.9% +/- 4.2%, suggesting that iron supplements were underused or erythropoietin doses were lower than optimal. Virtually all patients (94%) had received initial diet instruction but few (6%) received follow-up nutrition counseling.

CONCLUSION

Greater attention to dialysis adequacy, hematocrit levels, nutrition assessment, weight monitoring, and diet therapy are recommended.

Use of ACE inhibitors is associated with prolonged survival of arteriovenous grafts

Vascular access complications are common in hemodialysis patients. To investigate whether the use of angiotensin-converting enzyme (ACE) inhibitors influences the rate of polytetrafluoroethylene (PTFE) graft complications, we compared the rate of intervention-free graft survival among patients treated versus not treated with ACE inhibitors. We retrospectively analyzed the survival of grafts placed at our institution between January 1, 1995, and October 31, 1999. Among 121 grafts, 25 grafts were placed in 19 patients treated with ACE inhibitors and 96 grafts were placed in 68 patients not treated with ACE inhibitors. Follow-up ranged from 1 month to 5 years. Ten of 25 grafts failed in the ACE-inhibitor group and 62 of 95 grafts failed in the non-ACE-inhibitor group. Actuarial intervention-free access survival rates (Kaplan-Meier) were significantly greater in the ACE-inhibitor than non-ACE-inhibitor group (71% versus 53% at 6 months, 58% versus 35% at 12 months, and 44% versus 22% at 24 months; P = 0.04). Using a Cox model adjusting for age, race, sex, and diabetes, the relative risk (RR) for access failure in the ACE-inhibitor group was 53% less than in the non-ACE-inhibitor group (RR, 0.47; p < 0.03). In a more complex Cox model with additional adjustment for comorbid conditions, the RR was even lower (RR, 0.32; P = 0.003) for the ACE-inhibitor compared with non-ACE-inhibitor group (reference = 1.00). The lower RR was observed for patients with and without congestive heart failure. These results suggest that ACE inhibitors offer clinical promise in the prevention of PTFE graft failure. A prospective randomized trial is warranted to confirm the benefit of ACE inhibitors.

Evidence for high incidence of end-stage renal disease in patients after stroke and acute myocardial infarction at age 60 or younger

The impact of stroke and acute myocardial infarction (AMI) on the incidence of end-stage renal disease (ESRD) is unknown. Two community-based registries, one of patients with stroke or AMI and another of patients with ESRD who undergo dialysis, are available in Okinawa, Japan. Whether survivors after stroke and AMI who were registered from April 1988 through March 1991 entered an ESRD dialysis program by the end of December 1999 was determined. Among 4,556 patients (3,809 patients with stroke, 747 patients with AMI) who survived at least 28 days after the event onset, 44 patients (36 patients, stroke; 8 patients, AMI) entered an ESRD dialysis program during the study period. The 10-year cumulative incidence of ESRD was approximately 2.0% in those who survived stroke or AMI. The observed-expected ratio was 4.1 in men (P < 0.01) and 5.8 in women (P < 0.01) aged 30 to 59 years and 0.8 in men (not significant) and 0.4 in women (not significant) 60 years and older. The present results confirm that survivors after stroke or AMI have a greater incidence of ESRD than those in the general population, in particular, those who had stroke or AMI at 60 years or younger.