F.M. van der Sande

Cost-effectiveness of Vascular Access for Haemodialysis: Arteriovenous Fistulas Versus Arteriovenous Grafts

BACKGROUND The use of an arteriovenous fistula (AVF) for haemodialysis treatment may be associated with a high early failure rate, but usually good long-term patency, while using an arteriovenous graft (AVG) yields a lower early failure rate with worse long-term patency. The aim of this study was to calculate and compare the costs and outcome of AVF and AVG surgery in terms of early and long-term patencies. METHODS A decision tree and a Markov model were constructed to calculate costs and performance of AVFs and AVGs. The model was populated with a retrospective cohort of HD patients receiving their first VA. The outcomes were determined probabilistically with a 5-year follow-up. RESULTS AVFs were usable for a mean (95% CI) of 28.5 months (24.6-32.5 months), while AVGs showed a patency of 25.5 months (20.0-31.2 months). The use of AVFs was the dominant type of VA and € 631 could be saved per patient/per month patency compared to AVG use. Regardless of the willingness to pay, the use of AVFs yielded a higher probability of being cost-effective compared to AVGs. CONCLUSIONS AVFs are more cost-effective than AVGs. Nonetheless, early failure rates significantly influence AVF performance and initiatives to reduce early failure can improve its cost-effectiveness.

Comparison of Outcomes on Continuous Ambulatory Peritoneal Dialysis Versus Automated Peritoneal Dialysis: Results from a USA Database

♦ Background and Objective: Automated peritoneal dialysis (APD) is being increasingly used as an alternative to continuous ambulatory peritoneal dialysis (CAPD). However, there has been concern regarding reduced sodium removal leading to hypertension and resulting in a faster decline in residual renal function (RRF). The objective of the present study was to compare patient and technique survival and other relevant parameters between patients treated with APD and patients treated with CAPD. ♦ Methods: Data for incident patients were retrieved from the database of the Renal Research Institute, New York. Treatment modality was defined 90 days after the start of dialysis treatment. In addition to technique and patient survival, RRF, blood pressure, and laboratory parameters were also compared. ♦ Results: 179 CAPD and 441 APD patients were studied. Mean as-treated survival was 1407 days [95% confidence interval (CI) 1211 – 1601] in CAPD patients and 1616 days (95% CI 1478 – 1764) in APD patients. Adjusted hazard ratio (HR) for mortality was 1.31 in CAPD compared to APD (95% CI 0.76 – 2.25, p = NS). Unadjusted as-treated technique survival was lower in CAPD compared to APD, with HR 2.84 (95% CI 1.65 – 4.88, p = 0.002); adjusted HR was 1.81 (95% CI 0.94 – 3.57, p = 0.08). Peritonitis rate was 0.3 episodes/patient-year for CAPD and APD; exit-site/tunnel infection rate was 0.1 and 0.3 episodes/patient-year for CAPD and APD respectively (p = NS). ♦ Conclusions: Patient survival was not significantly different between APD and CAPD patients, whereas technique survival appeared to be higher in APD patients and could not be explained by differences in infectious complications. No difference in blood pressure control or decline in RRF was observed between the 2 modalities. Based on these results, APD appears to be an acceptable alternative to CAPD, although technique prescription should always follow individual judgment.

Seasonal Variations in Mortality, Clinical, and Laboratory Parameters in Hemodialysis Patients: A 5-Year Cohort Study

BACKGROUND AND OBJECTIVES Mortality varies seasonally in the general population, but it is unknown whether this phenomenon is also present in hemodialysis patients with known higher background mortality and emphasis on cardiovascular causes of death. This study aimed to assess seasonal variations in mortality, in relation to clinical and laboratory variables in a large cohort of chronic hemodialysis patients over a 5-year period. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This study included 15,056 patients of 51 Renal Research Institute clinics from six states of varying climates in the United States. Seasonal differences were assessed by chi-squared tests and univariate and multivariate cosinor analyses. RESULTS Mortality, both all-cause and cardiovascular, was significantly higher during winter compared with other seasons (14.2 deaths per 100 patient-years in winter, 13.1 in spring, 12.3 in autumn, and 11.9 in summer). The increase in mortality in winter was more pronounced in younger patients, as well as in whites and in men. Seasonal variations were similar across climatologically different regions. Seasonal variations were also observed in neutrophil/lymphocyte ratio and serum calcium, potassium, and platelet values. Differences in mortality disappeared when adjusted for seasonally variable clinical parameters. CONCLUSIONS In a large cohort of dialysis patients, significant seasonal variations in overall and cardiovascular mortality were observed, which were consistent over different climatic regions. Other physiologic and laboratory parameters were also seasonally different. Results showed that mortality differences were related to seasonality of physiologic and laboratory parameters. Seasonal variations should be taken into account when designing and interpreting longitudinal studies in dialysis patients.

Peritoneal Dialysis in Patients with Primary Cardiac Failure Complicated by Renal Failure

Background/Aims: Clinical outcome in cardiorenal syndrome type II and treated with peritoneal dialysis (PD). Methods: Retrospective analysis over a period of 10 years. Results: Twenty-four patients with mean age at start of dialysis of 67 ± 10 years had mean survival on dialysis of 1.03 ± 0.84 years (median survival 1.0 year). The number of hospitalizations for cardiovascular causes were reduced (13.7 ± 26.5 predialysis vs. 3.5 ± 8.8 days/patient/month postdialysis, p = 0.001). Patients who survived longer than the median survival time (n = 12) also had a reduced number of hospitalizations for all causes (3.7 ± 3.8 predialysis vs. 1.4 ± 2.1 days/patient/month postdialysis, p = 0.041), a lower age (62 ± 10 vs. 71 ± 8 years, p = 0.013) and fewer had diabetes (2 vs. 7 patients, p = 0.039), but left ventricular ejection fraction was not different. Conclusion: After starting PD for cardiorenal syndrome, hospitalizations for cardiovascular causes were reduced for all patients. Survival after starting PD is highly variable. Age and diabetes seem to be significant prognostic factors, but not left ventricular ejection fraction.

Prospective Evaluation of Ischemia in Brachial–Basilic and Forearm Prosthetic Arteriovenous Fistulas for Hemodialysis

UNLABELLED Ischemia is a devastating complication after arteriovenous fistula (AVF) creation. When not timely corrected, it may lead to amputation. Symptomatic ischemia occurs in 3.7-5% of the hemodialysis population. Upper arm AVFs have a higher incidence of ischemia compared to forearm AVFs. As more patients may need upper arm AVFs in the growing and older hemodialysis population, occurrence of symptomatic ischemia may increase. The purpose of this study is to identify predictors for occurrence of ischemia. METHODS A prospective evaluation of ischemia was performed in patients randomised for either a brachial-basilic (BB-) AVF or a prosthetic forearm loop AVF. Clinical parameters, preoperative vessel diameters, access flows, digital blood pressures, digit-to-brachial indices (DBI) and interventions for ischemia were recorded. RESULTS Sixty-one patients (BB-AVF 28) were studied. Seventeen patients (BB-AVF 8) developed ischemic symptoms. Six patients (BB-AVF 3) needed interventions for severe symptoms. Age, history of peripheral arterial reconstruction and radial artery volume flow were significant predictors for the occurrence of ischemia. CONCLUSION Symptomatic ischemia occurred in 28% of patients with brachial-basilic and prosthetic forearm AVFs. Age, history of peripheral arterial reconstruction and radial artery volume flow might be important for prediction of ischemia.

Feasibility of Non-contrast-enhanced Magnetic Resonance Angiography for Imaging Upper Extremity Vasculature Prior to Vascular Access Creation

OBJECTIVES Preoperative mapping of arterial and venous anatomy helps to prevent postoperative complications after vascular access creation. The use of gadolinium in contrast-enhanced (CE) magnetic resonance angiography (MRA) has been linked to nephrogenic systemic fibrosis in patients with end-stage renal disease (ESRD). The purpose of this study was to evaluate non-contrast-enhanced (NCE) MRA for assessment of upper extremity and central vasculature and to compare it with CE-MRA. METHODS NCE and CE-MRA images were acquired in 10 healthy volunteers and 15 patients with ESRD. In each data set, two observers analysed 11 arterial and 16 venous segments with regard to image quality (0-4), presence of artefacts (0-2) and vessel-to-background ratio. RESULTS More arterial segments were depicted using CE-MRA compared to NCE-MRA (99% vs. 96%, p = 0.001) with mean image quality of 3.80 vs. 2.68, (p < 0.001) and mean vessel-to-background ratio of 6.47 vs. 4.14 (p < 0.001). Ninety-one percent of the venous segments were portrayed using NCE-MRA vs. 80% using CE-MRA (p < 0.001). Mean image quality and vessel-to-background ratio were 2.41 vs. 2.21 (p = 0.140) and 5.13 vs. 3.88 (p < 0.001), respectively. CONCLUSIONS Although arterial image quality and vessel-to-background ratios were lower, NCE-MRA is considered a feasible alternative to CE-MRA in patients with ESRD who need imaging of the upper extremity and central vasculature prior to dialysis access creation.

The Predictive Value of C-Reactive Protein in End-Stage Renal Disease: Is It Clinically Significant?

Cardiovascular disease is the leading cause of death in patients with end-stage renal disease. Besides traditional risk factors, disturbances in mineral and bone metabolism and inflammation are thought to be responsible for the increased risk of death. In the last years C-reactive protein (CRP) has gained a lot of attention in the general population, especially with regard to its link with atherosclerosis. Although several studies suggest that CRP may be useful as a parameter in predicting future cardiovascular events in both the general population and in patients with end-stage renal disease, there is doubt about the clinical evidence of this assumption. A statistical association between CRP and cardiovascular disease was observed in various studies, but the predictive power of this association is markedly diminished when adjusted for other risk factors. The relative contributions of CRP as a marker, as a causative agent, or as a consequence of atherosclerotic vascular disease are unclear, both in the general population and in the dialysis population. The CRP levels are highly variable and influenced by intercurrent events in dialysis patients. In dialysis patients, it is possible to reduce the CRP levels by statins, although these agents do not reduce the cardiovascular mortality in diabetic dialysis patients.

Hypotension and Ultrafiltration Physiology in Dialysis

One of the main goals of dialysis therapy in patients with end-stage renal failure is removal of excess fluid that has accumulated during the interdialytic period. In this respect, hemodynamic instability with symptomatic hypotension will remain one of the most important complications in dialysis therapy especially as the number of elderly, cardiovascular-compromised patients on dialysis is still increasing. Although recent data are lacking, the incidence of hypotensive episodes is still reported to be around 20%. Symptomatic hypotension is not only a burden for the patient it also implicates expensive interventions leading to less effective treatment. Furthermore, recent data showed that also low preand postdialysis systolic blood pressures are increasing the relative risk for mortality in dialysis patients [1]. Moreover, blood pressure is even decreasing further as compared to the postdialysis blood pressure in some patients in the first 5–6 h after dialysis, as could be shown by Battle et al. [2]. Therefore, it is of utmost importance to optimize dialysis therapy with respect to blood pressure stability. Already in the late 1970s, Bergström [3] and Quellhorst et al. [4] showed that blood pressure was better maintained when fluid was withdrawn during either isolated ultrafiltration or hemofiltration as compared to combined ultrafiltration hemodialysis. Differences in blood volume preservation due to osmotic changes as well as differences in vascular reactivity due to differences in increase of sympathetic tone has been held responsible for the disparity in blood pressure stability [5, 6]. A theoretical analysis of the pathophysiology of intradialytic hypotension reveals 3 important factors: the fall in blood volume, a reduced vascular reactivity, which will even enhance the effect of structural cardiovascular abnormalities like decreased left-ventricular compliance [7].

Monitoring dialysis outcomes across the world--the MONDO Global Database Consortium

Background/Aims: Dialysis providers frequently collect detailed longitudinal and standardized patient data, providing valuable registries of routine care. However, even large organizations are restricted to certain regions, limiting their ability to separate effects of local practice from the pathophysiology shared by most dialysis patients. To overcome this limitation, the MONDO (MONitoring Dialysis Outcomes) research consortium has created a platform for the joint analysis of data from almost 200,000 dialysis patients worldwide. Methods: We examined design and operation of MONDO as well as its methodology with respect to patient inclusion, descriptive data and other study parameters. Results: MONDO partners contribute primary databases of anonymized patient data and collaboratively analyze populations across national and regional boundaries. To that end, datasets from different electronic health record systems are converted into a uniform structure. Patients are enrolled without systematic exclusions into open cohorts representing the diversity of patients. A large number of patient level treatment and outcome data is recorded frequently and can be analyzed with little delay. Detailed variable definitions are used to determine if a parameter can be studied in a subset or all databases. Conclusion: MONDO has created a large repository of validated dialysis data, expanding the opportunities for outcome studies in dialysis patients. The density of longitudinal information facilitates in particular trend analysis. Limitations include the paucity of uniform definitions and standards regarding descriptive information (e.g. comorbidities), which limits the identification of patient subsets. Through its global outreach, depth, breadth and size, MONDO advances the observational study of dialysis patients and care.

Surgical techniques to improve cannulation of hemodialysis vascular access

OBJECTIVE Successful access cannulation is of utmost importance for adequate hemodialysis treatment. Upper arm fistulae, obesity and deep or tortuous veins may impair needling and can cause significant complications and inconvenience for the patient. In the ultimate case, cannulation problems lead to temporary central vein catheter use for dialysis or even to irreversible access loss. Surgical access revision may enhance successful cannulation. METHODS A systematic literature review of all publications related to hemodialysis vascular access, cannulation complications and treatment was performed. RESULTS A total of 384 publications were identified, of which only 17 were related to treatment of cannulation complications in large patient populations. The clinical success rate of surgical intervention with vein elevation or transposition ranges from 85% to 91%. The 1-year primary and secondary patencies are 60% and 71%, respectively. Lipectomy results in an initial success rate of 100% with a primary and secondary patency of 71% and 98%, respectively, after 1 year of follow-up. CONCLUSION Surgical revision to improve hemodialysis vascular access cannulation has a high clinical success rate with good long-term patency.