Vascular Access Failure Research Articles

Pressure profile analysis at hemodialysis needle: a new method for early detection of vascular access stenoses

HEMODIALYSIS vascular access complications, such as thromboses due to flow limiting stenosis, are a major cause of morbidity and mortality in chronic renal failure patients [1, 2]. The Kidney Disease Outcomes Quality Initiative (K/DOQI) clinical practice guidelines define a stenosis significant at 50 % diameter reduction, accompanied by a hemodynamic or clinical abnormality [1]. Since, flow limitation and pressure drop rise appear only at a diameter reduction above 70%, the current vascular access surveillance techniques (flow measurements and static-access pressure measurements) are unable to detect early stenosis (<50% diameter reduction) and cannot further reduce the incidence of vascular access failure due to thrombosis [3, 4]. To overcome the inability to predict early stage stenoses and the low sensitivity of current tests, a new, non-invasive method based on pressure profile analysis (PPA) was studied. Therefore, an in vitro model of a radio-cephalic arterio-venous fistula was built.

Clinical Practice Guidelines for evidence-based use of erythropoietic-stimulating agents

BACKGROUND In patients with chronic kidney disease (CKD), anemia is associated with left ventricular hypertrophy and adverse cardiovascular and clinical outcomes. Moreover, anemia is associated with a reduction in quality of life, particularly when the hemoglobin level drops below 100 g/l. 1 Thus, the goal of treating anemia in iron-replete patients with erythropoietic-stimulating agents (ESAs) is to reduce the likelihood of cardiovascular events, improve patients’ survival, and improve patients’ quality of life while minimizing any deleterious effects of the drug. Given that ESAs increase blood pressure and have other potential side effects, it is also important to assess whether the quantity of the ESA used might contribute to adverse events such as more rapid deterioration of kidney function, earlier requirement for dialysis, and vascular access failure. It is acknowledged that, if left untreated, patients with severe anemia may require blood transfusions, which have associated risks and costs, and possible implications for patients awaiting a kidney transplant. In light of this, in most developed countries, the question for CKD patients with significant anemia has often not been whether to use ESAs, but when to use them and what target hemoglobin level to aim for. 2 The earliest anemia correction studies in nondialysischronic kidney disease (ND-CKD) and hemodialysis-chronic kidney disease (HD-CKD) patients compared the use of erythropoietin a with placebo. 3–5 Most early studies were not designed and powered to examine clinical outcomes other than quality of life, and no differences were apparent in such other outcomes. Several of the studies showed improvements in quality of life compared with placebo. 3–5 Subsequent randomized control trials (RCTs) have tended to examine the impact of using ESAs to achieve different target hemoglobin level ranges on surrogate endpoints, such as left ventricular (LV) mass, where patients with the lower hemoglobin target would be less likely to require the use of an ESA or would require lower doses to maintain the prespecified lower target hemoglobin. Two RCTs 6,7 in HDCKD patients compared with the use of ESAs to achieve intermediate hemoglobin and high hemoglobin targets. Although both studies showed no difference in progression of LV mass, the higher target hemoglobin led to improved quality of life in some of the domains, but the size of this

Pharmacological approaches to preventing vascular access failure

Date written: December 2006Final submission: March 2008

HOming in on arteriovenous fistula survival

Vascular access failure is a major clinical problem for patients on hemodialysis, but therapeutic approaches aimed at improving arteriovenous fistula (AVF) dysfunction remain elusive. Using a murine AVF model, Juncos et al. demonstrate for the first time that the stress protein heme oxygenase-1 (HO-1) is induced in AVFs and that HO-1 is a critical determinant of AVF survival.

Obesity as a Predictor of Vascular Access Outcomes: Analysis of the USRDS DMMS Wave II Study

Arteriovenous fistulae (AVF) are widely regarded as the preferred vascular access in hemodialysis patients due to their primary patency and patient survival benefits. While the obesity paradox has been associated with improved cardiovascular morbidity and all-cause mortality in dialysis patients, its long-term vascular access outcomes are less clear. Recent literature has suggested that obese patients may have increased early and late fistula failure. The purpose of this study was to explore the relationships between obesity and vascular access outcomes. We performed a retrospective cohort analysis using the USRDS DMMS Wave 2 data set. All incident dialysis patients as of January 1, 1996, over the age of 18, receiving only hemodialysis as mode of renal replacement therapy were eligible for inclusion. Among other variables, data collected for the DMMS Wave 2 included: type and location of vascular access, AVF maturity, vascular access revision, and failure. Logistic regression analyses were used to examine the relationships between obesity and vascular access outcomes, adjusting for important covariates. In all, 1486 hemodialysis patients were included. Using body mass index (BMI) <30 kg/m(2) as reference, obesity did not emerge as a factor in predicting vascular access revisions or failures. An increased risk of AVF failure to mature was found only in the highest BMI quartile (>or=35 kg/m(2)) (aOR 3.66 [95% CI 1.27-10.55], p = 0.017). Peripheral vascular disease was independently associated with an increased risk of AVF failure (aOR 2.78 [95% CI 1.01-7.63], p = 0.047) and arteriovenous graft (AVG) failure (aOR 1.65 [95% CI 1.03-2.64], p = 0.036). Obesity was not associated with increased AVF or AVG revision rates or failure and only associated with poorer AVF maturity at highest BMI quartile. We conclude that obesity should not preclude placement of AVF as vascular access of choice, except in the very obese where assessment should be individually based.

A Rare Look at a Cause for Vascular Access Failure After Correct Needle Placement Under Ultrasound Guidance

A Rare Look at a Cause for Vascular Access Failure After Correct Needle Placement Under Ultrasound Guidance

A mathematical model of venous neointimal hyperplasia formation.

BackgroundIn hemodialysis patients, the most common cause of vascular access failure is neointimal hyperplasia of vascular smooth muscle cells at the venous anastomosis of arteriovenous fistulas and grafts. The release of growth factors due to surgical injury, oxidative stress and turbulent flow has been suggested as a possible mechanism for neointimal hyperplasia.ResultsIn this work, we construct a mathematical model which analyzes the role that growth factors might play in the stenosis at the venous anastomosis. The model consists of a system of partial differential equations describing the influence of oxidative stress and turbulent flow on growth factors, the interaction among growth factors, smooth muscle cells, and extracellular matrix, and the subsequent effect on the stenosis at the venous anastomosis, which, in turn, affects the level of oxidative stress and degree of turbulent flow. Computer simulations suggest that our model can be used to predict access stenosis as a function of the initial concentration of the growth factors inside the intimal-luminal space.ConclusionThe proposed model describes the formation of venous neointimal hyperplasia, based on pathogenic mechanisms. The results suggest that interventions aimed at specific growth factors may be successful in prolonging the life of the vascular access, while reducing the costs of vascular access maintenance. The model may also provide indication of when invasive access surveillance to repair stenosis should be undertaken.

Interleukin-10 and Tumor Necrosis Factor-α Polymorphisms in Vascular Access Failure in Patients on Hemodialysis: Preliminary Data in Korea

Neointimal hyperplasia causes vascular stenosis and subsequent thrombosis, which result in vascular access failure in patients undergoing hemodialysis. Interleukin-10 (IL-10) and tumour necrosis factor-α (TNF-α ) are involved in this inflammatory process. The aim of this study was to investigate the relationship between vascular accessm failure and various inflammatory markers including the genetic polymorphisms of IL-10 and TNF-α . Seventy-five patients on hemodialysis with an arteriovenous fistula in place or an artificial graft (18 with vascular access failure and 82 without failure) and 98 healthy individuals were genotyped for IL-10 and TNF-α single nucleotide polymorphisms. Clinical and laboratory data including serum IL-10 and TNF-α levels were compared. Stimulated IL-10 levels, from in vitro incubation of blood with lipopolysaccharide, were also obtained and compared. Female gender, hypoproteinemia, and hypertriglyceridemia were associated with vascular access failure. The basal TNF-α level was significantly higher in patients with access failure. The distribution of IL-10 and TNF-α genotype did not differ among patients with or without access failure. This study could not demonstrate a relationship between genetic polymorphisms and vascular access failure. However, an altered immune response and inflammation might contribute to vascular access failure.

Long‐term outcomes of transposed basilic vein arteriovenous fistulae

The need for reliable, long-term hemodialysis vascular access remains critical. To determine the long-term outcomes of transposed basilic vein arteriovenous fistulae (BVT) and their comparability with other vascular accesses, we determined retrospectively the primary and secondary patency rates in 58 BVT and in a total of 58 arteriovenous fistulae (AVF) and arteriovenous grafts (AVG) at a single center. Fifty-eight BVT were placed in 57 individuals, 69% after prior vascular access failure. Ten BVT failed before initial use and 2 patients expired with functioning accesses before dialysis initiation. In all 58 BVT, 46.8+/-10.8% functioned at 3 years, with median survival 30.8 months. Limiting analyses to the 46 BVT that were ultimately accessed, 3-year primary and secondary patency rates were 38.3+/-7.7% and 56.5+/-12.6%, respectively. Lower ejection fraction (p=0.054) and greater numbers of prior permanent dialysis catheters (p=0.005) were present in those with failed BVT. Compared with AVF, BVT had similar 3-year primary and secondary patency rates. The secondary patency rate was significantly better for BVT vs. AVG over the observation period; at 3 years, the rates were 56.5+/-12.6% vs. 9.1+/-6.0% (p=0.002), respectively. Basilic vein arteriovenous fistulae are valuable hemodialysis accesses. Although nearly 20% of newly placed BVT will not function before first use, those that are functional have median survivals exceeding 6 years, and 38% will not require intervention within 3 years of initial use.

Predictors of Early Dialysis Vascular-Access Failure after Thrombolysis

Background: Vascular-access patency is critical for effective and uninterrupted haemodialysis. Limited literature exists evaluating if a surgical or repeated radiological approach is superior for reocclusion following failure of radiological recanalization. Few consistent early predictors of failure have been identified after radiological intervention for thrombosed vascular access. Methods: 138 patients with thrombosed arteriovenous fistulas or prosthetic grafts treated by radiological intervention, over 10 years, were retrospectively investigated. Reocclusion was treated by either repeated thrombolysis or surgery. Radiological patency rates, after first and second episodes of access thrombosis at 12 months after intervention were analysed. Surgical and radiological patency rates for second access thrombosis were compared. The Cox and logistic regression models were used to identify potential factors associated with reocclusion. Results: In patients who experienced reocclusion within 1 month after radiological intervention, the 3-month repeated radiological patency rate (n = 13) was 38.5%, compared to a 60% surgical patency rate (n = 10), but this did not reach statistical significance. Radiological patency rates after first access thrombosis at 3 and 12 months were 56.6 and 39.5%, respectively. In contrast, radiological patency rates after a second access thrombosis were 51.1 and 24.4%, respectively; a statistical difference in success was not achieved. Native arteriovenous fistulas were 3.23 times as likely to remain patent over 12 months following a first radiological intervention (p < 0.02) and less likely to experience a second reocclusion event (p < 0.01). Anticoagulation was associated with a lower risk of second reocclusion, whilst a history of venous thrombosis was associated with a greater risk (p < 0.02). Conclusion: Surgery achieves superior patency rates compared to repeated radiological interventions and should be considered if reocclusion occurs within a month following radiological thrombolysis.

Obesity and Hemodialysis Vascular Access Failure

A variety of factors have been proposed to explain arteriovenous fistula primary failures in patients undergoing hemodialysis, including obesity, diabetes mellitus, female sex, and the absence of preoperative vein mapping. In this report, we describe 2 women for whom premature upper-extremity arteriovenous fistula failures occurred in the setting of venographic evidence of soft-tissue compression of the venous outflow with the patient's arm in the adducted position. In each instance, preoperative noninvasive duplex vein mapping showed veins of adequate diameter (0.28 to 0.54 cm), and further evaluation showed no evidence of a hypercoagulable state. Upper-extremity venography was used to assess central venous patency and fully assess the venous vasculature. Unlike the widely patent venous systems seen in the abducted position, venography performed with the upper extremities in adduction showed marked narrowing of the brachial and/or axillary veins. The hemodynamic effects of this narrowing were readily apparent in patient 2 with the appearance of collateral filling of the cephalic vein in the adducted position. Patient 1 had a body mass index of 39 kg/m(2), and patient 2 had a body mass index of 34 kg/m(2). Each patient had excess axillary soft tissue that appeared to compress the venous outflow in adduction. To our knowledge, this is the first report to radiographically document soft-tissue compression of the venous outflow of the upper extremity in the adducted position, suggesting a mechanism whereby obesity, or at least excess axillary fat, can lead to premature hemodialysis vascular access failures.

Assisted Peritoneal Dialysis

Elderly patients are the largest and fastest growing group of patients with chronic kidney disease maintained on dialysis in the world. Because of advanced age and a heavy burden of comorbidities, the elderly are usually not candidates for kidney transplantation and are less likely to be offered peritoneal dialysis (PD). There is, however, growing evidence that the use of community nurses to assist with PD and the introduction of programs for assisted peritoneal dialysis (aPD) targeting these frail, elderly patients may enable more elderly patients to have their PD treatment at home. Suitable candidates for aPD are incident end-stage kidney disease patients preferring PD but unable to perform their own treatment because of comorbidities, physical disabilities, or psychosocial problems; prevalent, previous autonomous PD patients who have lost their independence because of advanced age or an increased burden of comorbidities; or prevalent hemodialysis (HD) patients switched from HD to aPD because of their own preference, failure of vascular access for HD, or an inability to tolerate HD. We believe that aPD in the future will prove to be a safe and feasible complementary alternative to in-center HD for the growing group of frail, elderly patients with end-stage kidney disease.

Local Activation of Interleukin 6 Signaling Is Associated With Arteriovenous Fistula Stenosis in Hemodialysis Patients

Vascular access failure is the main cause of morbidity in hemodialysis patients. Stenosis of the arteriovenous fistula (AVF) is similar histologically to atherosclerosis. Recent studies showed that interleukin 6 (IL-6) has a key role in the pathogenesis of atherosclerosis by binding 2 specific receptors, gp80 and gp130. When activated, gp130 interacts with a tyrosine kinase, Janus kinase (JAK2), which then activates a transcription factor, signal transducers and activators of transcription (STAT3), directly turning on several proinflammatory genes. The aim of this study is to evaluate gp130 expression and JAK2/STAT3 activation within stenotic AVFs. 44 patients undergoing surgery for AVF creation were enrolled; 10 of them had AVF failure with histologically proven AVF stenosis (wall-lumen ratio > 1). A venous fragment of the AVFs was collected during creation and revision of the vascular access. gp130 and gp80 expression, as well as JAK/STAT activation, were evaluated by means of confocal microscopy. Peripheral-blood mononuclear cells were isolated at the time of AVF creation and revision. gp130 protein expression, barely detectable in native AVFs, was strikingly increased within the venous branch of stenotic AVFs. The signaling subunit of the IL-6 receptor broadly colocalized with gp80, the IL-6-binding subunit. gp130-expressing cells were mainly CD34(+), suggesting that this receptor is expressed primarily by neovasculature endothelial cells. At the same time, a significant increase in phosphorylation of JAK2/STAT3 was observed in endothelial cells of stenotic AVFs. Interestingly, peripheral-blood mononuclear cells isolated at the time of AVF failure presented strikingly greater IL-6 expression compared with dialysis age-matched controls. IL-6 receptor activation may have a role in the pathogenesis of AVF failure in hemodialysis patients and may represent a potential therapeutic target in this setting.

Early Experiences of Intraoperative Ultrasound Guided Angioplasty of the Arterial Stenosis during Upper Limb Arteriovenous Fistula Creation

In recent years the high prevalence of diabetes and atherosclerosis in elderly uremic patients starting hemodialysis (HD) has led to the increase in the risk of vascular access (VA) failure caused by pre-existing arterial diseases, including both VA slow maturation and early failure, and upper limb ischemic symptoms. Recently, in performing radial (R), brachial (B) and ulnar (U) artery (A) percutaneous transluminal angioplasty (PTA) in HD patients affected by access thrombosis, with insufficient blood flow and severe upper limb ischemia, good outcomes have been reported. Nevertheless, these procedures were performed after arteriovenous fistula (AVF) creation. About 2 years ago, we approached an intra-operative ultrasound-guided transluminal angioplasty (IUTA) performed during AVF creation, using the arterial incision, necessary because of the anastomosis, to introduce the necessary devices for the IUTA. The arterial stenosis having undergone IUTA was diagnosed by a preliminary ultrasound examination. Ultrasound guidance during the procedure is necessary for correct balloon location in the stenosis site. We treated seven patients (four diabetics), mean age 76 + 5 yrs. In all cases, the radial arteries because of hyposphygmia, were unfit for AVF creation. Four distal radio-cephalic AVFs at the wrist were created in patients 1, 3, 4 and 5; in the other three patients (2, 6 and 7), with failure or thrombosis of previous distal AVFs, an immediately upstream anastomosis was performed. In all cases, first, the area selected to perform the AV anastomosis was exposed, then the AR was incised, and the introductory metallic guide wire and the angioplasty catheter (with dimensions decided after PUS), were introduced. The balloon was inflated to 8–13 atm for 30–35 sec. In two patients a stent was also positioned. Later, a side-to-side AVF was created, closing the distal venous vessel. Patient follow-up ranged from 6–22 months. The ultrasound evaluation after IUTA showed the correction of all the stenosis treated. AVF maturation was good, except for the stented ones, which were inadequate. In conclusion, our early experience shows IUTA could be an adequate and effective procedure allowing the use of the stenotic arteries (otherwise unsuitable) for AVF creation. In our experience, stenting after IUTA does not add any other advantages.

The Effect of Patient Age and Other Factors on the Maintenance of Permanent Hemodialysis Vascular Access

The objective of the present study was to investigate whether patient age is associated with vascular access failure during maintenance hemodialysis. Thus, patients who had a successful permanent hemodialysis vascular access installed (Group N: 314 cases), and those who required vascular access revision (Group R: 108 patients) were studied. To assess the association between patient age and the risk of vascular access failure, Cox proportional hazards regression was used to determine hazard ratios (HR) and 95% confidence intervals (CI). We found that in Group N, the significant risk factors were age, gender, and diabetes mellitus (95% CI: 1.004-1.013, 0.380-0.827, 1.279-2.859). Using a univariate analysis model, significant hazard ratios (HR) were found with ages of 60 (CI: 1.062-2.302), 65 (CI: 1.052-2.280), and 70 (CI: 1.082-2.537) years, with the largest HR at 70 years of age (HR: 1.657). In contrast, in Group R, multivariate analysis using Cox proportional hazards identified only one prognostic variable, the location of the vascular access. In Group R, univariate analysis models showed that age was not a significant factor. We conclude that our data show that age is a risk factor for the successful maintenance of initial permanent hemodialysis vascular access. Other risk factors include gender and diabetes mellitus. However, these factors were not related to the successful maintenance of revised vascular access.

Gene Polymorphism Association Studies in Dialysis: Vascular Access

Complications of the vascular access site for hemodialysis are a major cause of morbidity, suboptimal dialysis, and hospitalization. Vascular access for dialysis that is achieved by central venous catheters is associated with complications such as infection and thrombosis. Arteriovenous fistulas and grafts are also at risk for infectious complications. Further, proliferation of the venous wall with secondary thrombosis is a common pathophysiological process that leads to vascular access dysfunction. Genetic polymorphisms that contribute to vascular access failure are found among factors of the coagulation cascade, and host mediators that induce endothelial dysfunction as well as vessel wall proliferation. The two most common mutations of coagulation factors seem to influence the risk of central venous catheter and fistula thrombosis. Indeed, both the single nucleotide polymorphism of the factor V gene at amino acid position 506 (factor V Leiden mutation) and the prothrombin 20210 polymorphism have been associated with thrombotic complications of the vascular access. Among the endothelium-directed factors, a polymorphism of the methylene tetrahydrofolate reductase gene coding for an enzyme that degrades the endothelium toxic product homocysteine, has been associated with fistula failure. While the angiotensin converting enzyme polymorphism does not seem to be associated with vascular access complications, polymorphisms of the profibrogenic cytokine transforming growth factor-beta1 are associated with the prognosis of native arteriovenous fistulae. The role of pro- and anti-inflammatory cytokine gene polymorphisms as prognostic factors for vascular access is yet to be clearly defined.

Endothelial Nitric Oxide Synthase Gene Intron 4 (VNTR) Polymorphism and Vascular Access Graft Thrombosis

Vascular access thrombosis is a leading cause of vascular access failure in hemodialysis patients. Thrombosis is a multifactorial condition and genetic makeup can affect thrombosis risk. We conducted a study to investigate for possible associations between ecNOS gene intron 4 variable-number tandem repeat (VNTR) polymorphism and thrombosis of polytetrafluoroethylene hemodialysis arteriovenous access grafts (AVG) in Turkish patients. Fifty-five patients with end-stage renal disease who had AVGs implanted between 2000 and 2002 and 167 healthy individuals representing our healthy population were enrolled in this prospective study. Each subject provided a venous blood sample from which DNA was isolated, and polymerase chain reaction analysis was done to identify genotypes (aa, bb, ab) for ecNOS gene intron 4 VNTR polymorphism. All grafts were placed in brachioaxillary position. The subjects were divided into two groups based on duration of graft patency. The thrombosis group (Group I) comprised 26 patients who developed AVG thrombosis in the first 12 months after placement. The no-thrombosis group (Group II) comprised 29 patients whose grafts remained patient for at least 12 months. The frequency of the aa genotype in Group I was significantly higher than that in Group II (p =. 005). At 6, 12, and 24 months, the primary patency rates for the AVGs in patients with the aa genotype were significantly lower than the corresponding rates for the bb and ab genotype groupings (p =. 01, p =. 01 and p =. 04 for the three respective time points; Kaplan–Meier). ecNOS gene intron 4 VNTR polymorphism is linked with the pathogenesis of vascular access thrombosis in Turkish patients undergoing hemodialysis.

Long-Term Peritoneal Dialysis Experience in Portugal

Peritoneal dialysis (PD) penetration varies widely. Since the beginning of this therapy, indications have changed and outcomes have improved. In Portugal, PD still remains clearly underutilized. The results of a 20 year PD programme were evaluated: 312 cumulative patients, 48+/-16 years, 27%>60 years old, 27% diabetic, 59% with prior hemodialysis (HD). The main reason for admission was vascular access failure (48.7%). Admission due to patient preference has increased significantly between first and second decades of the programme (33% vs 47% (P<0.001)); 98 patients (31.4%) were treated with automated PD but this prescription increased to 43% of the active patients.A total of 376 Tenckhoff catheters were surgically implanted, recently by the Popovich-Moncrief technique (77 catheters): the cumulative survival was 82%, 64% and 50% at 1, 3 and 5 years,respectively. A better catheter survival was found in the last decade (85.7%, 69.6%, 54.8% versus 77.3%, 55.5%, 40.2%, at 1, 3 and 5 years, respectively (P=0.007). The patient and technique cumulative survivals were 91, 74, 55% and 85, 67, 41%, at 1, 3, and 5 years, respectively. The main drop-out was to hemodialysis (35.8%), followed by death (23.7%), and transplantation (21.5%). Peritonitis and access-related infections caused 35% of the transfer to HD. Cardiovascular events caused 58% of deaths. The median PD retention was 35.5 months. The rate of peritonitis has decreased to one episode /30 patient months. Hospital admission has also decreased to 4.8 days/patient year. This is a first report on long-term PD experience in Portugal. It has been an effective modality of renal replacement therapy, reflected by the growing patient preference in our PD programme.Experience, knowledge and new technical solutions have improved the outcomes.

Vascular Access Outcomes and Medication Use: A USRDS Study

Several medications have been proposed to improve hemodialysis (HD) vascular access outcomes based on potentially favorable anticoagulant, antiplatelet, or pleiotropic properties. The purpose of this study was to evaluate the relationship between medication use and vascular access patency in a group of HD patients. We conducted a historical cohort study of the US Renal Data System Dialysis Mortality and Morbidity Wave II study to identify patients with an arteriovenous fistula (AVF), polytetrafluoroethylene (PTFE) graft, or a permanent catheter for vascular access. Cox regression analysis, adjusted for age, gender, race, history of coronary artery disease, peripheral vascular disease, or coronary artery bypass graft, was used to model the hazard ratio (HR) of permanent vascular access failure. Of the 2001 HD patients in the Wave II study, 901 (45%) were included in the analysis. PTFE graft patency was greater for males (HR, 0.73; 95% CI 0.53-1.00, p = 0.05) and for older individuals (HR, 0.99; 95% CI 0.98-1.00, p = 0.02). Treatment with antiplatelet medications, ticlopidine and dipyridamole (HR, 3.54; 95% CI 1.07-11.76; p = 0.04), or aspirin (HR, 2.49; 95% CI 1.31-4.73; p = 0.005) was associated with significantly worse AVF patency. Antiplatelet agents had a significant negative association with access patency in this cohort. In contrast to other published data, it was difficult to identify any beneficial effect of specific medications on access patency.

Impact of a quality improvement programme based on vascular access flow monitoring on costs, access occlusion and access failure

Vascular access thrombosis is a substantial source of morbidity in chronic haemodialysis patients. Periodical access flow measurements can predict the presence of vascular access stenosis and provide an opportunity for early intervention to prevent subsequent vascular access thrombosis. By this system of quality improvement, vascular access-related costs might be reduced. The aim of this study was to analyse the cost impact of a quality improvement programme based on periodic access flow measurements. The number and costs of vascular access interventions (summary of angiography, percutaneous transluminal angioplasty, catheter placement, hospitalization days and costs for surgery) in the period 2001-2003 (quality improvement period; QIP, 218.6 patient-years observed) were retrospectively compared with a reference period (RP, 1996-1998, 214.4 patient-years observed) during which no access flow was measured. All access flow measurements were done on a regular base and interventions were performed according to the Kidney Disease Outcome Quality Initiative. Surgical thrombectomy procedures were significantly less during the QIP (0.25 +/- 0.57 events/patient-year) compared with RP (0.63 +/- 1.06 events/patient-year; P = 0.000), whereas access loss was not significantly different. During the QIP, 205 radiological interventions were performed (0.88 +/- 1.16 events/patient-year), and in the RP around 48 (0.33 +/- 0.65 events/patient-year; P = 0.000). Access-related costs tended to be lower during the QIP compared with the RP. The cost reduction appeared to be limited to patients with arteriovenous graft (AVG), in which access-related costs were significantly lower during the QIP (2360.95 euro +/- 2838.17 euro patient-year) compared with the RP (4003.96 euro +/- 3810.92 euro patient-year; P = 0.012), but not in patients with arteriovenous fistula (AVF). A quality improvement programme based on periodical access flow measurement reduced the number of acute vascular access failures due to thrombotic events and also significantly reduced health care costs in patients with AVG, but not in patients with AVF. The quality improvement programme had no effect on access survival.