Arteriovenous Fistula Patency Rates Research Articles

Expected Flow Parameters Within Hemodialysis Access and Selection for Remedial Intervention of Nonmaturing Conduits

Persistent poor patency rates of arteriovenous fistulae and bridge grafts for dialysis access prompted us to investigate whether flow parameters derived from an initial postconstruction, precannulation duplex study could predict access longevity or direct remedial procedures to salvage nonmaturing conduits. We analyzed 125 consecutive dialysis access conduits (34 forearm fistulae, 53 arm fistulae, 38 prosthetic bridge grafts, 108 patients, 82 male/26 female, average age 58 years) over the past 5 years having early (2 to 8 weeks) duplex scanning done prior to attempted hemodialysis cannulation. Velocity waveforms were recorded in the arterial inflow, arterial and venous anastomoses, mid-conduit, and in the venous outflow with averaging of volume flow rate (product of average velocity and cross-sectional area) measured at 3 mid-conduit sites. Conduits were deemed "adequate" for dialysis cannulation or "nonmaturing" by the presence of detected high-grade stenoses (peak systolic velocity >400cm/s, velocity ratio >3, and minimal diameter <2 to 3 mm) and subjected to remedial interventions (endovascular or open). Subsequent access function for hemodialysis use and late patency were recorded and correlated with early duplex findings. Average flow rates (forearm fistula 784 +/- 623 mL/min, arm fistula 1400 +/- 850, bridge graft 1270 +/- 604) and mid-conduit peak-systolic velocities (215 +/- 214 cm/s forearm fistula vs 312 +/- 194 arm fistula) differed between conduit type and location. Remedial interventions were needed in 10 (26%) bridge grafts and 18 (21%) fistulae "nonmaturing" due to occlusive lesions. Conduit flow rates differentiated "nonmaturing" (606 +/- 769 mL/min) and "maturing" (1140 +/- 857) fistulae (P = .01). A threshold conduit flow rate of 800 mL/min better discriminated failing and functional fistulae and bridge grafts (accuracy 77%) than a flow rate greater or less than 500 mL/min (accuracy 67%). Remedial interventions doubled average flow rates of "nonmaturing" accesses (from 605 to 1159 mL/min) to values similar to "mature, functional" conduits (1374 mL/min) and facilitated a mean duration of patency (12.9 months) equivalent to conduits not needing remedial interventions (11.5 months). Duplex-derived hemodynamic parameters characterized early dialysis access conduit function, prognosticated access patency, guided necessary remedial interventions, and facilitated favorable access longevity.

Effect of Operating Surgeon on Outcome of Arteriovenous Fistula Formation

To study whether surgical trainees can perform arteriovenous fistula (AVF) surgery to a standard comparable to consultants. Retrospective study of all vascular access surgery over a three year period at a single centre. The operating surgeon was identified from theatre log books and categorised by grade. Fistula patency was used as the primary outcome measure and was determined from patients' case-notes and from a prospectively collected electronic record of dialysis sessions. Patency was defined as "used for dialysis" if the AVF was used for dialysis for at least 6 consecutive sessions. One hundred and eighty six cases were used for analysis. In 60 cases (32%) the operating surgeon was the consultant, in 53 cases (29%) a trainee was supervised by a consultant, in 56 cases (30%) a trainee performed the operation independently and in 17 cases (9%) the grade of the operating surgeon could not be established. Primary and primary assisted patency rates by operating surgeon did not differ significantly (P-values 0.25 and 0.16 respectively). Age of the patient was the only predictor of patency failure in a multivariate model. Grade of operating surgeon (logrank test chi(2)=3.1, p=0.38) and type of fistula (logrank test chi(2)=2.3, p=0.52) were not significantly related to the primary survival of the fistula. This study showed no significant differences in AVF patency rates between trainee and consultant surgeons. Allocation of appropriate cases can result in trainees obtaining similar outcomes as consultants, demonstrating that dialysis access surgery can provide good training opportunities for junior doctors without detriment to patient care.

Can the National Kidney Foundation Guidelines for First-Time Arteriovenous Fistula Creation Be Met in Underserved End-Stage Renal Disease Patients?

The aims of this study were to determine whether National Kidney Foundation (NKF) guidelines for native arteriovenous fistula (AVF) creation (at least 50% of all new end-stage renal disease [ESRD] patients and 40% of prevalent hemodialysis patients) could be met in an underserved population who presented in late stages of ESRD. We also sought to determine 1-year AVF patency rates and factors associated with early thrombosis. One hundred seventy-six patients underwent hemodialysis access surgery during the period 2003-2005 with a mean age of 51 years. Sixty-two percent were male, and 48% had diabetes mellitus. Ultrasound vein mapping was performed in only 37%. Temporary central venous access was necessary in 109 patients (62%) due to late presentation. Of the 160 patients who were first-time access, 137 (86%) received a native AVF and 23 (14%) had an arteriovenous graft. There was a higher rate of AVF creation in males (91% vs. 75% for females, p = 0.005). The 1-year primary patency was 90%. There were no differences in early thrombosis or 1-year patency rates with respect to gender, age, ethnicity, insurance status, presence of temporary access, or use of preoperative vein mapping. In an underserved population, NKF guidelines for native AVF for first-time access can be superseded with an excellent 1-year patency, despite late presentation.

Comparison of classical and non-classical cardiovascular risk factors influencing the patency of native arteriovenous fistulas after percutaneous transluminal angioplasty therapy among haemodialysis patients

Objective: To evaluate the classical and non-classical cardiovascular risk factors that effect patency of native arteriovenous fistulas (AVF) in end stage renal disease (ESRD) patients who are undergoing regular haemodialysis...

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.

Keyhole technique for autologous brachiobasilic transposition arteriovenous fistula

Autologous brachiobasilic transposition arteriovenous fistulas (AVFs) are desirable but require long incisions and extensive surgical dissection. To minimize the extent of surgery, we developed a catheter-based technique that requires only keyhole incisions and local anesthesia. The technique involves exposure and division of the basilic vein at the elbow. A guidewire is introduced into the vein, and a 6F "push catheter" is advanced over the guidewire and attached to the vein with sutures. Gently pushing the catheter proximally inverts, or intussuscepts, the vein. Side branches that are felt as resistances when pushing the catheter forward are localized, clipped, and divided under direct vision. Throughout the procedure, the endothelium always remains intraluminal. The basilic vein is externalized at the axilla without dividing it proximally and is tunneled subcutaneously, where it is anastomosed to the brachial artery. Thirty-two patients underwent the procedure--31 as outpatients. The mean duration of operation was less than 90 minutes. All patients tolerated the procedure well, and 31 required only intravenous sedation and local anesthesia. At a mean follow-up of 8 months, the primary patency rate of AVFs in patients with basilic vein diameters of 4 mm or more on preoperative duplex ultrasonography was 80%, vs 50% for those with vein diameters less than 4 mm. Overall, 78% of patent AVFs were being successfully accessed and 22% were still maturing at last follow-up. Autologous brachiobasilic transposition AVFs can be created by using catheter-mediated techniques that facilitate the mobilization and tunneling of the basilic vein through small incisions. Medium-term data suggest that the inversion method results in acceptable maturation and functionality of AVFs created with this technique.

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.

Immediate hemodialysis after percutaneous transvenous angioplasty increases patency rates of arterio-venous fistula

It was reported that pathogenesis of access failure of hemodialysis patients through progressive stenosis was followed by thrombosis. Nonionic contrast media increase platelet degranulation within an angioplasty-damaged vessel by releasing procoagulant molecules, which might contribute to acute thrombosis and restenosis. An adequate level of heparin provides satisfactory thrombin inhibition during routine angioplasty. This study was performed to evaluate the effect of immediate hemodialysis after percutaneous transvenous angioplasty (PTA) to remove nonionic contrast media or other factors while injecting heparin continuously. From September 9, 1998 - May 15, 2002, successful PTAs were performed in 66 patients with arteriovenous fistula who were not given any inhibitors of platelet aggregation. Hemodialysis was performed in 31 cases immediately after PTA, and in the remainder, hemodialysis was performed the next day. Patients were randomized and fistula patency rates were compared in these 2 groups on March 20, 2004. The patency rates after PTA in patients who were dialyzed immediately, were significantly higher than those who were dialyzed the next day (p = 0.0120). Immediate hemodialysis after PTA is an effective way of increasing the patency of arteriovenous fistula for reasons which are not clear. This observation will need to be corroborated in subsequent studies using a larger sample size.

Native arteriovenous fistula: Preoperative evaluation

Duplex sonography recently has been recognized as an objective and noninvasive method to assess morphological and functional parameters of vessels that could predict arteriovenous fistula (AVF) patency and time of adequate maturation. To prospectively study prognostic indicators of native AVFs, forearm arteries and veins of patients with end-stage renal disease were examined by duplex sonography before AVF construction. Several anatomic parameters, including feeding artery internal diameter (IDA), resistance index (RI), and arterial blood flow (QA) before and at reactive hyperemia (RH) and internal diameter of the vein (IDV) before and after proximal vein compression (PVC), were measured. Measurements of the feeding artery were repeated at different periods after native AVF construction. One hundred sixteen patients were included on the study. The primary patency rate (successful constructed AVF) of native AVFs was 80.2%. In this group, mean values for IDA were 0.264 cm; RI at RH, 0.50; and QA, 54.5 mL/min. IDV increased after PVC for 59.3%. In the group with failed AVFs (19.8%), mean IDA was 0.162 cm; RI at RH, 0.70; and QA, 24.1 mL/min. IDV increased after PVC for only 12.4%. Patency rates after surgery in a group with IDAs greater than 0.16 cm was 93%, and with IDAs of 0.16 cm or less, 32%. In a group with RIs at RH less than 0.7, the patency rate was 95.3%, and with RIs of 0.7 or greater, 38.7%. An AVF feeding artery QA of 300 mL/min was achieved in the group with IDAs greater than 0.16 cm, those with RIs at RH less than 0.7 after 1 week, those with IDAs of 0.16 cm or less between 3 and 8 weeks, and those with RIs of 0.7 or greater between 8 and 12 weeks. This study shows that duplex sonography may provide useful data on preoperative morphological and functional characteristics of vessels used for AVF construction. Increase in IDA, QA, RI at RH, and IDV after PVC are important to predict AVF primary patency rate. Based on these measurements, the most adequate location for AVF construction, as well as time of optimal AVF development, can be determined, particularly for patients at greater risk for primary failure, such as the elderly and patients with diabetes. © 2002 by the National Kidney Foundation, Inc.

Venous Rupture Complicating Hemodialysis Access Angioplasty: Percutaneous Treatments and Outcomes

Purpose: To evaluate the usefulness of percutaneous management and prognosis in venous rupture during angioplasty of hemodialytic arteriovenous fistulas. Materials and Methods: Among 814 patients who underwent angioplasty on account of inadequate hemodialysis, 63[39 women and 24 men aged 20-78 (mean, 55.8) years] were included in this study. All 63 had peripheral venous stenosis. Venous rupture was diagnosed when contrast leakage was seen at venography after percutaneous angioplasty (PTA). In order to manage venous rupture, the sites at which this occurred were compressed manually for 3-5 minutes or blood flow was blocked with a balloon catheter for the same period. In one case, a stent was inserted at the rupture site. Using the Kaplan-Meier method, we investigated the patency rate of arteriovenous fistula (AVF) in cases of successful PTA. We also compared PTA patency rates in cases with and without peripheral venous rupture. Results: Venous rupture occurred in 38 cephalic, 16 brachial, and 9 basilic veins. In 63 patients, bleeding stopped and in 54 (85.7%) of these, PTA was successful. Among the nine failed cases, dilatation was incomplete in five, though bleeding had stopped. In patients with brachial and cephalic vein rupture, the venous tract at the rupture site was not located. Two patients underwent surgery: one of these experienced brachial venous rupture, with incontrollable bleeding, and the other had nerve compression symptoms due to hematoma. Among 54 patients in whom PTA was successful, the primary and secondary six-month rates for angioaccess were 47.9% and 81.2%, and the mean patency period was 6.1 and 15.8 months, respectively. In cases of non-venous rupture, the mean patency period was 9.6 months, significantly longer than in cases involving venous rupture (p=0.02). Conclusion: Venous rupture occurring during the PTA of hemodialytic AVF can be managed percutaneously.

Primary Vascular Access for Chronic Hemodialysis: A Comparison of Arteriovenous Fistulae with PTFE Grafts

The purpose of this study was to compare patency rates of arteriovenous fistula (AVF) and polytetrafluoroethylene grafts (PTFE) for hemodialysis and the complications associated with each. All new permanent vascular access procedures for hemodialysis performed at one institution between January 1989 and December 1993 were reviewed with follow-up to December 1995. Patient demographics, secondary operations, complications, and length of stay were compared between the two types of access strategies. Seventy-seven PTFE and 89 AVF were performed in 166 patients. Age, sex, and frequency of diabetes were similar between the two groups. Primary patency rate at 36 months for AVF was 53%, compared with 16% for PTFE (p&lt;0.01). Secondary patency rate at 36 months was 70% for AVF and 50% for PTFE (p&lt;0.02). PTFE was associated with more hospital days per patient per year (26 vs 6.9), more infections (12 vs one during secondary patency interval), and a higher initial failure rate (19 vs eight) as compared with AVE. Patient survival rate at 4 years was higher for those with AVF (65% vs 52%). We conclude that an AVF as the primary access procedure for new renal dialysis patients is preferable to PTFE whenever possible.

Longitudinal comparison of dialysis access methods: Risk factors for failure

Purpose: To compare dialysis access patency rates and identify risk factors for failure. Methods: All access procedures at our institution from 1987 to 1996 were reviewed. Primary procedures were surgically implanted dual-lumen central venous hemodialysis catheters (SIHCs), peritoneal dialysis catheters (PDCs), arteriovenous fistulas (AVFs), and prosthetic shunts (PTFEs). Results: Five hundred eighty-five primary procedures (236 PTFEs, 87 AVFs, 112 SIHCs, and 150 PDCs) and 259 secondary procedures (215 PTFEs, 14 AVFs, 0 SIHCs, and 30 PDCs) were performed on 350 patients. By life table analysis, SIHCs exhibited the lowest primary patency rate (9% at 1 year; p < 0.0001), whereas PDCs had the highest primary patency rate (57% at 1 year; p < 0.02). The primary patency rates of AVFs and PTFEs was similar, with 43% and 41% 1-year patency rates, respectively ( p = 0.70). Less-stringent reporting methods would have increased apparent 1-year patency rates by 9% to 41%. With regard to secondary patency, there was no significant difference between PTFEs and PDCs, with 1-year patency rates of 59% and 70%, respectively ( p = 0.62), but PTFEs were more frequently revised. In addition, there was no significant difference between AVF and PTFE secondary patency rates, with 1-year patency rates of 46% and 59%, respectively. Early differences in patency rates for AVFs, PTFEs, and PDCs diminished over time, and at 4 years AVFs had the best secondary patency rate ( p = 0.6). The most common reasons for access failure were: PTFEs, thrombosis; AVFs, thrombosis and failure to mature; SIHCs, inadequate dialysis; PDCs, infection and inadequate exchange. By regression analysis, a history of a previous unsalvageable PTFE was the only significant risk factor for failure of a subsequent PTFE ( p < 0.01), and the risk of graft failure increased exponentially with the number of previous PTFE shunts. Diabetes was the only significant risk factor for failure of PDCs ( p < 0.02; odds ratio, 2.0). Conclusions: The patency rate for PTFEs is similar to that for AVFs, but AVFs require fewer revisions. When replacing a failed access graft, the risk of PTFE failure increases with the number of prior unsalvageable PTFE shunts. PDCs have excellent patency rates, but failure rates are doubled in patients with diabetes. Because of poor patency rates and inadequate dialysis flow rates, SIHCs should be avoided when possible. Reporting methods dramatically affect apparent patency rates, and reporting standards are needed to allow meaningful comparisons in the dialysis access literature. (J Vasc Surg 1997;26:1009-19.)

Comparison of basilic vein and polytetrafluoroethylene for brachial arteriovenous fistula

Purpose: The aim of this study was to compare patency and complication rates between basilic vein and polytetrafluoroethylene (PTFE) for brachial arteriovenous fistulas (AVF) for long-term hemodialysis.Methods: All basilic vein and PTFE brachial AVF constructed between March 1988 and April 1993 were retrospectively reviewed. After construction of life-tables, log-rank testing was used to compare the primary patency rate of basilic vein AVF (n = 59) with the primary and secondary patency rates of PTFE AVF (n = 47). Complication rates were calculated for each type of fistula and compared by use of chi-squared testing.Results: The primary patency rate for basilic vein AVF (90%) was superior to that of PTFE AVF (70%) at 1 year (p < 0.01), and at 2 years (86% vs 49%, p < 0.001). Complications occurred two and a half times more frequently in the PTFE group than in the basilic vein group (p < 0.05).Conclusions: Basilic vein AVF provided superior patency rates and lower complication rates compared with PTFE AVF. Prospective randomized trials comparing the two fistula types is required to firmly establish the basilic vein AVF as the alternative access procedure of choice after a failed or unconstructable radiocephalic fistula.