Fistula In Hemodialysis Patients Research Articles

Some Old Drugs Improve Late Primary Patency Rate of Native Arteriovenous Fistulas in Hemodialysis Patients

Vascular access failure causes 20% of all hospitalizations of dialysis patients. Native arteriovenous fistulas, the best type of dialysis vascular access, have a 1-year primary patency rate that is extremely variable, ranging 40-80%. Neointimal hyperplasia is the most important cause of arteriovenous fistula late primary dysfunction. In recent years the arteriovenous fistula late primary patency rate has not improved because of the increase of old uremic patients with a high number of comorbidities and the lack of new therapeutic interventions. Therefore, we performed a long-term case-control study to analyze which factors or drugs may affect native arteriovenous fistula late primary patency rate in 60 incident hemodialysis patients. The arteriovenous fistula late primary patency rate was 75.1% after 12 months, 58.5% after 24 months, and 50% after 987 days. Homocysteine levels during follow-up had a significant direct association with vascular access failure (event vs. event-free 28.5+/-1.9 vs. 22.3+/-1.2 micromol/L, p<0.01). Folate values had a trend toward an inverse relationship with arteriovenous fistula failure (event vs. event-free 11.5+/-1.2 vs. 14.6 vs. 1.1 ng/mL, p=0.06). Patients treated with folic acid and/or statin had an arteriovenous fistula late primary patency rate significantly higher than patients without folic acid and statin therapy, respectively, 81.7% vs. 66% after 1 year and 71.5% vs. 39.1% after 2 years (p=0.02). Many other factors were not associated with vascular access failure. Statin and homocysteine-lowering folic acid therapy is associated with prolonged arteriovenous fistula survival. It is important to perform randomized trials to verify our observation.

Calcium Channel Antagonists Reduce Restenosis After Percutaneous Transluminal Angioplasty of an Arteriovenous Fistula in Hemodialysis Patients

Percutaneous transluminal angioplasty (PTA) for stenosis of hemodialysis fistulas is associated with a high incidence of restenosis, and improvement of the patency rate after PTA is greatly needed. In addition, angiotensin II receptor blockers (ARB), calcium channel antagonists (CCA) and antiplatelet agents (APA) are commonly administered to most hemodialysis patients. This study retrospectively examined the effect of these medications on the incidence of restenosis after angioplasty for hemodialysis fistulae. The subjects were 92 patients--54 with anastomotic stenosis of an arteriovenous fistula (AVF) and 38 with stenosis of the draining veins of an arteriovenous graft (AVG)--who underwent angioplasty between January 2001 and December 2003. The patency period was defined as the interval from the first to the second angioplasty or surgical reconstruction. We excluded patients who received angioplasty two or more times. The effect of each drug on the patency of the AVF or AVG was assessed by the Kaplan-Meier method with the log-rank test and multiple logistic regression analysis. The group receiving CCA therapy showed a higher patency rate for both an AVF and an AVG. Although multiple logistic regression analysis also showed that a CCA reduces restenosis independently in an AVF, there was no significant correlation between a CCA and patency in an AVG. Treatment with an ARB and an APA was not associated with significantly higher patency rates for either an AVF or AVG. A CCA may reduce the incidence of restenosis after percutaneous intervention for stenosis of an AVF.

The D&amp;T Report

The D&amp;T Report

Far-infrared irradiation can improve blood flow and patency of arteriovenous fistulas in hemodialysis patients

Far-infrared irradiation can improve blood flow and patency of arteriovenous fistulas in hemodialysis patients

Over-expression of IGF-related peptides in stenoses of native arteriovenous fistulas in hemodialysis patients

Introduction Insulin-like growth factors (IGFs) are known to play an important role in atherogenesis. The aim of our study was to assess the local expression of IGF-related peptides in stenosed hemodialysis fistulas and compare these with their respective serum levels. Methods We investigated 15 stenosed vein segments of primary arteriovenous fistulas, 29 non-stenosed control vein segments from uremic patients and 15 non-stenosed control saphenous vein segments. Immunohistochemistry was performed for IGF-I, insulin, IGF-binding proteins (IGFBPs)-1, -2, -3 and -4, the acid labile subunit (ALS) and type 1 IGF-receptor (IGF-R). Serum levels were measured by specific radioimmunoassays. Results Compared to both control groups, a significantly higher expression of the following IGF-related peptides was seen in the stenotic (neo)intima: IGF-I, IGFBP-1, -2, -3, -4 and IGF-R; in the stenotic media: IGF-I and IGFBP-3 and in the endothelium of stenotic fistulas: IGF-I (all p < 0.05). Staining against ALS and insulin was negative in all vessels. Serum IGF-I levels did not differ. Serum levels of IGFBP-1, -2, -3 and -4 were significantly higher in patients with renal disease (all p < 0.05). There were no correlations between local and systemic IGF-related peptide levels. There were correlations of neointimal expression of IGF-I, IGFBP-1, -2, -3, -4 and IGF-R with both hypercellularity and the presence of inflammatory cells ( p < 0.05). Conclusion In the stenotic arteriovenous fistula of hemodialysis patients, expression of the peptides IGF-I, IGFBP-1, -2, -3, -4 and IGF-R was significantly increased and showed a positive correlation with neointimal inflammation and hypercellularity (all p < 0.05). IGF-related peptides are most likely synthesized locally and might be involved in the initiation and/or progression of neointimal thickening of primary arteriovenous fistulas.

Vascular Access Outcomes as a Predictor of Development of Chronic Allograft Nephropathy

Introduction The vascular condition influences the outcomes of arteriovenous fistula (AVF) surgery. However, it has not been established how it influences the outcomes of renal transplantation and the development of chronic allograft nephropathy (CAN). The aim of this study was to define the relationship between AVF failure in the pretransplant period and the development of CAN. Patients and methods In this study we included all patients who underwent AVF surgery and then first kidney allotransplantations from January 1, 1999 to December 31, 2002. Patients were divided into two groups according to the AVF surgery outcomes: group 1 ( n = 45, mean age 50 ± 13 years, male/female ratio 27/18) had no vascular access complications and were dialysed through a native AVF. Group 2 ( n = 39, mean age 51 ± 11 years, male/female ratio 17/22) had additional interventions due to AVF failure. We analyzed the incidence of CAN in both groups. Results During the follow-up period CAN was observed in five patients in group 1 and 11 patients in group 2 (11,1% vs 28,2%, P < .05). There was a statistically significant relationship between CAN and acute rejection episodes ( P < .005) and diabetes mellitus ( P < .05). Conclusion Failures of arteriovenous fistulas in hemodialysis patients were associated with an increased incidence of CAN in the posttransplant period.

Influence of Homocysteine on the Function of Native Arteriovenous Fistula in Hemodialysis Patients

Background Vascular access (VA) for hemodialysis (HD) is crucial for the course of treatment and a good prognosis for patients. There have been numerous investigations of the influence of homocysteine (Hcy) on VA complications, but to date the role of Hcy is controversial. The present study of HD patients was designed to investigate the relationship between previous VA failure (VAF) and the serum level of Hcy and other routinely measured biochemical parameters. Patients and Methods Eighty-five patients participated in the study. Their mean age was 62 years, and their mean duration on HD treatment was 33 months. Incidence of VAF over the preceding 18 months was analyzed retrospectively. VAF was defined as any dysfunction of VA that required a different surgical intervention. Serum levels of Hcy and several other biochemical parameters related to the adequacy of HD, osteodystrophy, nutrition status, and atherosclerosis were determined. In addition, body mass index, normalized protein catabolic rate, and mean blood pressure were calculated. Additionally, the serum level of Hcy was determined in a healthy control group (n=12). Results VAF, as venous or graft thrombosis (n=12) and stenosis of anastomosis (n=13), was observed in 25 of the HD patients (30%). Mean Hcy level was significantly higher in the HD patients than in the control group (26.8±9.5 vs. 11.8±2.9 μmol/L, p <.01). Mean Hcy level was significantly higher in patients with VAF than in the other HD patients (31.8±10.3 vs. 25.1±8.5 μmol/L, p <.005). There were no differences in age, duration of HD, and cause of renal failure, as well as in the other measured parameters, between these groups of patients. Conclusion Patients with extremely elevated Hcy levels had higher incidences of VAF, and needed surgical intervention more frequently.

Which factors are associated with failure of arteriovenous fistulas in hemodialysis patients?

Which factors are associated with failure of arteriovenous fistulas in hemodialysis patients?

The Impact of Intima-media Thickness of Radial Artery on Early Failure of Radiocephalic Arteriovenous Fistula in Hemodialysis Patients

This study was performed to investigate the impact of intima-media thickness (IMT) of radial artery on early failure of radiocephalic arteriovenous fistula (AVF) in hemodialysis (HD) patients. Ninety uremic patients undergoing radiocephalic AVF operation were included in this study. During the operation, 10-mm long partial arterial walls were removed with elliptical form for microscopic analysis. Specimens were stained with trichrome and examined by a pathologist blinded to the clinical data. And then AVF patency was followed up for 1 yr after the operation. Of the total 90 patients, 31 patients (34%) had AVF failure within 1 yr after the operation. Mean IMT was thicker in failed group (n=31) than in patent group (n=59) (486±130 µm vs. 398±130 µm, p=0.004). The AVF patency rate within 1 yr after the operation was lower in patients with IMT ≥500 µm (n=26) than in patients with IMT <500 µm (n=64) (p=0.017). Age was an independent risk factor of IMT. Diabetes mellitus tended to be independent risk factor but not statistically significant. Our data suggest that increased radial artery IMT is closely associated with early failure of radiocephalic AVF in HD patients.

Association between Carpel Tunnel Syndrome and Arteriovenous Fistula in Hemodialysis Patients

Carpal tunnel syndrome is more common in hemodialysis patients than in the general population. In addition to uremic neuropathy, arteriovenous fistula has been identified as one of the possible causes for the development of carpal tunnel syndrome. Wrists of 279 hemodialysis patients who had arteriovenous fistula for at least 6 months served as the case group and the other intact wrists of the same patients served as the control group. Carpal tunnel syndrome was diagnosed clinically; however, 116 random patients underwent electrodiagnostic studies the day after hemodialysis. Clinically, carpal tunnel syndrome was diagnosed less frequently in the contralateral wrist than in the wrist with arteriovenous fistula (12.2 percent versus 30.5 percent, p < 0.0001). Meanwhile, the authors found a positive correlation between the duration of fistula and the development of carpal tunnel syndrome (p < 0.028). The site of fistula (snuffbox, radiocephalic) used, however, had no effect on the rate of development of carpal tunnel syndrome (p > 0.2). Contrary to the clinical assessment, electrodiagnostic studies did not indicate any significant association between the frequency of carpal tunnel syndrome and arteriovenous fistula or its duration. With the nerve conduction velocity abnormalities observed in patients with uremic polyneuropathy, the authors believe that clinical diagnosis of carpal tunnel syndrome is more indicative of the development of the condition than the electrodiagnostic results. The authors' clinical results have revealed that hemodialysis patients are at considerable risk of developing carpal tunnel syndrome in the wrist with an arteriovenous fistula. These patients should be under close observation and receive routine checkup.

Hemodialysis Complications

Hemodialysis Complications

798Native arteriovenous fistula in hemodialysis patients: The impact of clinical, nutritional, inflammatory, atherosclerotic and genetic factors on prognosis

_______________________________ Correspondence to: Serkan Kahraman, MD, Hacettepe Hastanesi, Nefroloji Bolumu, 06100-Sihhiye, Ankara-TURKEY, : +90-312324 3109, Fax: +90-312311 3958 marici@hacettepe.edu.tr Native Arteriovenous Fistula in Hemodialysis Patients: The Impact of Clinical, Nutritional, Inflammatory, Atherosclerotic and Genetic Factors on Prognosis Serkan Kahraman, Ender Ozden, Barbaros Baseskioglu, Gultekin Genctoy, Mustafa Arici, Ilhan Erkan, Mehmet Bakkaloglu, Sali Caglar Hacettepe University Faculty of Medicine, Department of Nephrology and Department of Urology, Ankara

Intima‐media thickness of radial artery is associated with early access failure in hemodialysis patients

Objective: We have reported that intimal hyperplasia, which is the pathologic change of the radial artery, is associated with early failure of arteriovenous fistula (AVF) in hemodialysis (HD) patients (Am J Kidney Dis, 41:422–428, 2003). Intima‐media thickness (IMT), which represents the whole thickness of arterial wall, can be easily measured by ultrasonography, unlike intima thickness. This study was performed to investigate the impact of IMT of radial artery on early failure of AVF in HD patients. Methods: Ninety HD patients undergoing radiocephalic AVF operation were included in this study. The AVF was constructed in an end vein–to–side artery fashion at the wrist by one vascular surgeon. During the operation, 10‐mm long partial arterial walls were removed with elliptical form for microscopic analysis. Specimens were stained with trichrome and examined by a pathologist blinded to the clinical data. AVF patency was prospectively followed up for 1 year after the operation. Results: Mean age of the patients was 56 ± 13 years and the number of females was 44 (48.9%). Mean IMT was 430 ± 132 μm (133–760 μm). Of the total 90 patients, 31 patients (34.4%) had AVF failure within 1 year after the operation. Mean IMT was higher in the failed group (n = 31) than in patent group (n = 59)(486 ± 130 μm vs. 330 ± 178 μm, p = 0.004). Using a threshold of 500 μm of IMT, AVF patency rate was compared between these two groups using Kaplan‐Meier method with log rank test. The AVF patency rate within 1 year after the operation was higher in patients with IMT ≥ 500 μm (n = 26) than in patients with IMT &lt; 500 μm (n = 64)(p &lt; 0.001). The patients with IMT ≥ 500 μm were older and had higher incidence of diabetes mellitus, compared to the patients with IMT &lt; 500 μm. There was no difference in sex, smoking, hypertension, total cholesterol and albumin levels between the two groups. Conclusion: Our data suggest that increased intima‐media thickness of radial artery is associated with early failure of radiocephalic arteriovenous fistula in hemodialysis patients.

Centered endovascular irradiation to prevent postangioplasty restenosis of arteriovenous fistula in hemodialysis patients: Results of a feasibility study

Purpose To report follow-up results of a prospective trial on centered endovascular gamma-irradiation (CEGI) after percutaneous transluminal angioplasty (PTA) for stenosis of arteriovenous fistula in hemodialysis patients. Methods and materials Eight patients receiving PTA for recurrent ( n=4) or de novo arteriovenous fistula stenoses were treated with CEGI with iridium-192 (14 Gy). Angiography was performed after 6 and 12 months or if problems reoccurred during hemodialysis. Parameters of hemodialysis and duplex sonography were determined the day before and after PTA and after 1, 3, 6, 9, and 12 months. Results CEGI was performed successfully and without complications in seven patients. In six patients, restenosis occurred 6–52 weeks (mean 20.8±17.9 weeks) after PTA and required PTA. Parameters of hemodialysis and duplex sonography deteriorated during follow-up. Conclusions Centered endovascular gamma-irradiation with iridium 192 immediately after PTA of fistula stenoses was a safe and feasible method but did not prevent restenosis.

Preexisting intimal hyperplasia of radial artery is associated with early failure of radiocephalic arteriovenous fistula in hemodialysis patients

Background: The radiocephalic arteriovenous fistula (AVF), which provides the best vascular access for hemodialysis, continues to have a high incidence of early failure. Intimal hyperplasia (IH) of the radial artery is observed commonly in uremic patients before hemodialysis, but the impact of this preexisting IH on the early failure of radiocephalic AVFs has not been reported yet. Therefore, we designed this study to: (1) investigate clinical risk factors for IH, and (2) determine whether preexisting IH of the radial artery is associated with early failure of a radiocephalic AVF. Methods: Specimens from the radial artery were obtained during the radiocephalic AVF operation. IH was measured with trichrome staining, and AVF patency was prospectively followed up for 12 months after the operation. Results: Of the 59 patients, 45 patients had evidence of IH in their radial artery (76.2%). Patients with IH (n = 45) were older than those without IH (n = 14; 58 ± 12 versus 44 ± 17 years; P = 0.003). The incidence of diabetes mellitus in patients with IH was greater than that in patients without IH (60.0% versus 28.6%; P = 0.004). Of the 57 patients, except for 2 patients who died before the end point of the study with patent AVFs, fistula failure was observed only in patients with IH (22 of 44 patients; 50% versus 0%; P < 0.001). The intima was thicker in the failed-AVF group than the patent-AVF group (93.1 ± 37.5 versus 45.6 ± 17.4 μm; P < 0.001). Conclusion: This study suggests that early failure of radiocephalic AVFs in hemodialysis patients is closely associated with preexisting IH of the radial artery. Am J Kidney Dis 41:422-428.

Gender differences in outcomes of arteriovenous fistulas in hemodialysis patients

The prevalence of arteriovenous (A-V) fistula use is lower among female than male hemodialysis patients. This difference may be due, in part, to smaller vessel diameter in women. However, even when routine preoperative vascular mapping is used to select vessels with suitable diameters, fistulas are still less likely to mature in women than in men. To explore the reasons for this gender discrepancy, we evaluated the outcomes of 230 A-V fistulas placed at our institution after preoperative mapping. Vessel diameters, radiologic and surgical interventions, and fistula adequacy for dialysis were assessed. Fistula adequacy for dialysis was lower in women than men (31 vs. 51%, P = 0.001). The inferior outcome of fistulas in women was observed for both forearm fistulas (18 vs. 43%, P = 0.02) and upper arm fistulas (39 vs. 60%, P = 0.04). Differences in vessel diameter did not explain the lower patency rate of fistulas among women. Among fistulas not lost due to technical failure or early thrombosis, 31% underwent one or more interventions (salvage procedures) due to failure to mature. These interventions included angioplasty, ligation of tributaries, superficialization, and surgical revision of the anastomosis. A salvage procedure was more likely in women than in men (42 vs. 23%, P = 0.04). The likelihood of fistula maturation after an intervention was similar among women and men (50 vs. 37%, P = 0.40). Salvage procedures increased the proportion of adequate fistulas to a greater degree in women than in men (relative increases of 68 and 15%, respectively). These data suggest that fistulas are less likely to be useable for dialysis in women than in men, despite routine preoperative mapping and frequent interventions undertaken to salvage immature fistulas.

Increasing arteriovenous fistulas in hemodialysis patients: Problems and solutions

Increasing arteriovenous fistulas in hemodialysis patients: Problems and solutions

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.

Access Blood Flow as a Predictor of Early Failures of Native Arteriovenous Fistulas in Hemodialysis Patients

Blood flow imaging using color doppler has proven effective in predicting graft failures in hemodialysis patients, but its effect on native arteriovenous fistulas (AVF) is not well known. This study was performed to investigate whether measurements of the access blood flow can be used as predictors of an early failure of a native AVF in hemodialysis patients. Fifty-three consecutive patients who received native AVF operations were included in this study. Access blood flow was measured at 1 week after operations, and AVF function was followed for 4 months. During the follow-up, access failures developed in 10 patients at 9.8 ± 3.5 weeks. AVF blood flow was significantly lower in the failure group (n = 10) than in the patent group (n = 43) (450 ± 214 vs. 814 ± 348 ml/min, p = 0.003). The incidence of access failures was higher in the patients with a flow <350 ml/min (n = 9) compared to the patients with a flow >350 ml/min (n = 44) (55.5 vs. 11.3%, p = 0.008). The diameters of veins were significantly smaller in the failure group than in the patent group (3.5 ± 0.5 vs. 4.1 ± 0.7 mm, p = 0.018). The incidence of diabetes mellitus was higher in the failure group than in the patent group (90 vs. 51%, p = 0.025). However, age, sex, duration from an operation to first cannulation, and different AVF sites did not make a significant difference between the two groups. Our data suggest that access blood flow measurements using color doppler ultrasound during early postoperative periods are useful parameters in predicting an early failure of a native AVF in hemodialysis patients.

Surgical Revision and Early Cannulation of the Arteriovenous Fistula in Hemodialysis Patients: An Effective Technique.

Arteriovenous fistula (AVF) dysfunction is a common problem in hemodialysis patients. After surgical revision for malfunction, we used AVFs early to avoid complications associated with central venous catheters. In this study, we report experience with surgical revisions of native AVFs with suspected arterial dysfunction as the cause of inadequate arterial inflow for dialysis. Exclusion criteria were presence of a central venous catheter as a hemodialysis access, and clinical or radiologic evidence of stenosis or thrombosis of the distal venous segment of the AVF. We prospectively studied 50 patients (mean age 60.2 ± 10.5 years, 25 men and 25 women) with 59 revisions. The patients were followed until change in the modality of dialysis, transplant, or death. The types of AVFs revised were left wrist radiocephalic in 27 patients (54%), left forearm radiocephalic in 10 (20%), right wrist radiocephalic in 6 (12%), left antecubital brachiocephalic in 3 (6%), right antecubital brachiocephalic in 2 (4%), and right forearm radiocephalic in 2 (4%). The causes of inadequate arterial flow were juxta-anastomotic thrombosis in 20 patients (40%), inadequate arterial anastomotic flow in 16 (32%), inadequate anastomosis in 7 (14%), and juxta-anastomotic venous stenosis in 7 (14%). The primary surgical revision techniques were proximal neo-anastomosis using the semiarterialized vein in 43 patients (86%), thrombectomy and re-anastomosis in 5 (10%), and resection and repair in 2 (4%). Technical success, defined as successful cannulation of the revised AVF for hemodialysis and avoidance of central venous catheter, was achieved in 44 of 50 patients (88%). Technical failure occurred 6 cases, the causes being inadequate arterial flow in 3 patients, failure to cannulate the veins in 2 patients, and steal syndrome in 1 patient. After primary revisions failed, 9 re-revisions were done in 6 patients. The 1-year, 2-year, and 3-year primary and overall patency rates were 76.2%, 67.6%, 65.0%, and 85.7%, 75.7%, 65.0%, respectively. In conclusion, surgical salvage of the AVF with inadequate arterial flow is an effective approach that can be performed as an outpatient procedure and allows early cannulation of the semi-arterialized veins, thus avoiding the use of central venous catheters.