Autogenous Arteriovenous Research Articles

Bone vascularized composite allotransplantation model in swine tibial defect: Evaluation of surgical angiogenesis and transplant viability.

In prior small animal studies, we maintained vascularized bone allotransplant viability without long-term immunotherapy. Instead, an autogenous neoangiogenic circulation is created from implanted vessels, sufficient to maintain bone viability with only 2 weeks immunosupression. Blood flow is maintained despite rejection of the allogeneic vascular pedicle thereafter. We have previously described a large animal (swine) pre-clinical model, reconstructing tibial defects with vascularized tibial allotransplants. In this manuscript, autologous angiogenesis is evaluated in this model and correlated with bone viability. Allogeneic tibial segments were transplanted across a major swine leukocyte antigen mismatch. Microvascular repair of the bone VCA pedicle was combined with intraosseous implantation of an autogenous arteriovenous (AV) bundle. The bundle was ligated in group 1 (n = 4), and allowed to perfuse in group 2 (n = 4). Three-drug immunotherapy was given for 2 weeks. At 16 weeks micro-CT angiography quantified neoangiogenic vessel volume. Bone viability, rejection grade, and bone healing were analyzed. A substantial neoangiogenic circulation developed from the implanted AV-bundle in group 2, with vessel density superior to ligated AV-bundle controls (0.11 ± 0.05 vs. 0.01 ± 0.01, P = .029). Bone allotransplant viability was also significantly enhanced by neoangiogenesis (78.7 ± 4.4% vs. 27.7 ± 5.8%, P = .028) with higher bone healing scores (21.4 ± 2.9 vs. 12.5 ± 3.7, P = .029). Ligated control tibias demonstrated disorganized bone morphology and higher local inflammation (P = .143). Implantation of autogenous AV bundles into vascularized bone allotransplants resulted in the rapid formation of a neoangiogenic autogenous blood supply in a swine tibia model that maintained bone viability, improved bone healing, and minimized rejection.

Successful Surgical Remodeling of a Giant Venous Aneurysm Formed in an Autogenous Arteriovenous Fistula: A Case Report

One complication of an autogenous arteriovenous fistula (AVF) for hemodialysis is the formation of a venous aneurysm. The treatment of a massive aneurysmal AVF generally involves ligation or resection with the use of prosthetic interposition. We present the case of a 46-year-old man in whom an AVF aneurysm was successfully treated by placating the excess free wall of the aneurysm with sutures. This method is a simple and effective intervention for managing aneurysm-associated complications. In addition, this approach helps to maintain the benefits of autogenous access while conserving future dialysis sites.

Primary Balloon Angioplasty Combined with Balloon-Assisted Maturation of Autogenous Arteriovenous Fistula in Patients with Small-Caliber Vasculature

Background: Failure or delayed maturation of arteriovenous fistula (AVF) in patients with end-stage renal disease (ESRD) who require hemodialysis (HD) can lead to catheter-related complications as bacteremia and sepsis with the resultant high morbidity and mortality. Small- diameter veins are often a limiting factor for the successful creation of arteriovenous fistulas (AVFs). Balloon-assisted maturation (BAM) is a recent, innovative, yet controversial method for developing autogenous arterio-venous fistulae (AVF). Purpose: Is to evaluate the use of intraoperative primary balloon angioplasty (PBA) as a technique to upgrade the small-caliber or diameter veins during AVF construction in conjunction with sequential balloon- assisted maturation to salvage failing fistulas, expedited maturation & improve the patency of AVFs. Materials and methods: Prospectively collected data over a 2-year period. Between January 2016 and December 2017, 121 patients who underwent AVF creation in two tertiary referral hospitals in Saudi Arabia, Vascular surgery Department, Nile Insurance Hospital & Vascular Surgery Unit, Benha University/Department of Surgery, Egypt, were retrospectively analyzed. The duration to maturation of the AVF was determined by comparing the period between the time of creation of the fistula and the first successful cannulation of the fistula for patients with ESRD on hemodialysis. Patients with peritoneal dialysis were excluded. Patients who underwent BAM or construction of AVF at an outside institution were excluded. Follow-up consisted reviewing of postoperative AVF duplex for patency, hemodialysis units, vascular and nephrology clinics databases, and telephone interviews. Successful outcome was determined as the functional ability to use the fistula for hemodialysis without surgical revision. Results: Of the 136 PBA procedures, 119 (87.5%) remained patent and subsequently underwent BAM with a resulting functional AVF. These consisted of 106 of the original AVFs and 13 new AVFs created at other sites. Occlusions occurred in 30 of the 121 fistulas (24.8%), and 15 were salvaged using BAM techniques. The mean balloon diameter for all dilatations was 3.5 mm. Of the initial 121 AVFs placed, 106 (87.6%) were made functional and 30 failed due to occlusion. Fifteen were salvaged using recanalization techniques and sequential BAM. Of the remaining fifteen patients, 11 were unsalvaged and received AVFs at another site using PBA and BAM techniques and 4 required graft placement. One AVF had to be ligated secondary to steal syndrome with insertion of chronic hemodialysis catheter as an alternative access. Overall 116 patients (95.9%) received working AVFs. All fistulas were functioning at 90 days after the final BAM. Graft placement was necessary in only 4 of the 121 patients (3.3%). Conclusion: The combination between PBA and BAM is an overall approach that facilitates AVF maturation, improves function, prolongs patency, and facilitates use of small-caliber veins as an autogenous vascular access. The shorter maturation times have reduced the overall need for indwelling catheters with their associated risks. The resulting large-diameter AVFs are easy to cannulate and are associated with improved flow and patency rates. Successful AVFs have been created using veins that would have otherwise been deemed unusable. Adoption of this conjoint technique should help meet the stringent demands for autogenous access placement defined by KDOQI and Fistula First Breakthrough Initiative (FFBI) and, thereby, improve the duration and quality of life for the hemodialysis patients

A Single-Center Retrospective Analysis of the Efficacy of a New Balloon Catheter in Autogenous Arteriovenous Fistula Dysfunction Resistant to Conventional Balloon Angioplasty

The purpose of the study was to present a new alternative balloon catheter option for autogenous arteriovenous fistula (AVF) dysfunction with a stiff constriction resistant to conventional balloon angioplasty. Our first series of 51 patients with autogenous AVF dysfunction who were simultaneously treated with VascuTrak™ balloon catheter, following failed conventional balloon therapy (failure was defined as residual stenosis of >30%), were retrospectively observed and analyzed. The indices that were used to evaluate the clinical efficacy of VascuTrak balloon catheter included the immediate technical success rate, residual stenosis, successful dilation times, degree of pain assessed using the Visual Analog Scale, complications, and follow-up patency rate. The stenotic or occlusive lesions of all 51 cases resistant to conventional balloon angioplasty were promptly eliminated or alleviated (residual stenosis rate≤30%), with a 100% immediate technical success rate. VascuTrak balloon catheters were successful in achieving full dilation under working pressure, of which 44 cases required a 1-time dilation (86.3%) and 7 cases required 2 dilations, which differed significantly from the average of 2.4 dilations required by the preceding conventional balloon therapy (P<0.0001). A statistically significant improvement in the degree of pain experienced by patients who received VascuTrak balloon dilation was observed compared to that of the preceding conventional balloon dilation (P<0.0001). One case of a brachial artery pseudoaneurysm complication occurred in the perioperative period. The primary patency rate was 88.2% at 6months and 74.5% at 12months. The use of VascuTrak balloon catheter to treat autogenous AVF dysfunction resistant to conventional balloon angioplasty appears to be safe and effective, although further, large randomized controlled trials are necessary.

Influence of Arterial and Venous Diameters on Autogenous Arteriovenous Access Patency

The autogenous arteriovenous fistula (AVF) is the standard procedure for patients requiring chronic hemodialysis. To enhance its success, preoperative duplex ultrasound has been used to determine fistula location based on venous and arterial diameters. Previous authors have suggested that a minimum outflow vein diameter (MOVD) and perianastomotic arterial diameter are associated with successful maturation. The goal of this study was to determine anatomic and clinical variables that may influence access patency to guide optimal autogenous access configuration selection. AVFs created from 2010 to 2016 were analyzed from data entered into a prospective database. Preprocedure duplex ultrasound mapping data of venous and arterial diameters and demographic and clinical variables were collected. Kaplan-Meier and Cox hazards analysis were used to assess patencies and maturation and to identify independent predictors of access failure. There were 535 AVFs were created (median follow-up, 17.0 months; range, 0-73 months). Of these, 265 (49.5%) were radiocephalic, 221 (41.3%) were brachiocephalic, and 49 (9.2%) were brachiobasilic. AVFs with an MOVD <3 mm were associated with inferior primary patencies at 12 months (43% ± 4% vs 54% ± 4%; P = .009) and 36 months (19% ± 4% vs 33% ± 4%) and secondary patencies at 12 months (75% ± 3% vs 91% ± 2%; P < .001) and 36 months (63% ± 4% vs 78% ± 4%; P < .001). Arterial diameter <2 mm for radiocephalic AVFs was associated with impaired maturation at 12 months in diabetics vs nondiabetics (53% ± 9% vs 87% ± 8%), with no differences observed in maturation rates with radial artery diameters >2 mm (84% ± 5% vs 85% ± 4%; P =.019). On multivariate regression, MOVD (hazard ratio [HR], 0.02; 95% confidence interval [CI], 0.01-0.23; P = .002), female sex (HR, 1.75; 95% CI, 1.12-2.73), and diabetes (HR, 1.67; 95% CI, 1.00-2.79; P =.048) were associated with secondary patency loss. MOVD is strongly predictive of autogenous access patency. Radial artery diameter <2 mm was predictive of radiocephalic AVF failure to mature, but only in diabetic patients.

The Clinical Efficacy of Balloon-Assisted Maturation of Autogenous Arteriovenous Fistulae

This retrospective study suggests that balloon-assisted maturation (BAM) of arteriovenous fistula (AVF) does not decrease maturation times and warrants further scrutiny before adoption more widely.

Predictors of Autogenous Arteriovenous Hemodialysis Access Thrombosis after Renal Transplantation

The fate of autogenous arteriovenous fistula (aAVF) after renal transplantation (RT) remains variable. The aim of this study was to determine the predictors for their thrombosis after RT. We conducted a monocentric retrospective review of prospective clinical records of 145 patients with a functional aAVF who had an RT between January 2004 and December 2009 in the University Hospital of Clermont-Ferrand. Our primary end point was the thrombosis of the aAVF. Univariate and multiple logistic regression analyses were used to identify risk factors associated to aAVF thrombosis after RT. There were 105 men (72%) and 40 women (28%), mean age 52years (range: 18.4-74.7years). The aAVF was created on average 40months (range: 2-169) before the RT. The aAVF was distal in 96 cases (66%) and proximal in 49 cases (34%). Nineteen aAVF (13.1%) were complicated and required an endovascular or surgical repair before RT. Forty-nine patients (34%) required multiple aAVF (>2). Mean follow-up from RT was 58months (range: 1day-123months) and from aAVF creation 97months (range: 5-262months). At the end of the follow-up, 81 aAVFs (59%) were patent, 42 (29%) were thrombosed, and 22 (15%) were surgically closed. Patients that had multiple fistulas before RT and active smokers were significantly at risk to thrombose their aAVF after the RT in univariate (P=0.03 and P=0.02, respectively) and multiple logistic regression analyses (P=0.03 and P=0.047, respectively). Thrombosis is a part of the natural history of the aAVF after RT. A history of multiple aAVF creations before RT and active smoking were associated to significant increased risk for fistula thrombosis. Because hemodialysis may be needed after RT, the aAVF patency should be preserved, excepted when the aAVF resulted in complications. Follow-up of the aAVF after RT is important to detect and treat complications before thrombosis occurs.

The Clinical Efficacy of Balloon-Assisted Maturation of Autogenous Arteriovenous Fistulae

Delayed maturation of arteriovenous fistulae (AVF) among patients who require hemodialysis (HD) can lead to catheter sepsis with its resultant morbidity and mortality. Some have proposed that sequential balloon-assisted maturation (BAM) may accelerate the maturation times of these accesses. On the other hand, serial balloon angioplasty of normal vein may result in stenosis and delay maturation. Although the safety of BAM has been shown, direct comparison to nonmatured AVF has not been explored. Therefore, we conducted a retrospective analysis of our prospectively maintained vascular access database to compare the duration of period to AVF maturation between patients who received BAM and those who were not referred for BAM at our institution. Prospectively collected data over a 3-year period in 194 patients who underwent AVF creation at our institution were retrospectively analyzed. The duration to maturation of the AVF was determined by comparing the period between the creation of the fistula and the first successful cannulation of the fistula. Only patients on HD were included. Patients who underwent BAM or placement of AVF at an outside institution were excluded. Follow-up consisted reviewing of postoperative AVF duplex for patency, hospital and clinic databases, HD center databases, and telephone interviews. Of the 194 patients who had AVF placement, 172 patients were on HD within 2weeks of AVF placement, whereas 22 patients had AVF placed in anticipation of the need for HD. Of the 172 patients on HD within 2 weeks, 54 patients had BAM performed at our institution and 4 patients had BAM at an outside institution, whereas 114 patients were not referred for BAM. Thirty-three of these 114 patients were age and gender matched to compare to the patients who underwent BAM at our institution. At the time of this analysis, of the 54 patients who had BAM, 30 had functional AVF (19 men, 11 women; mean age, 62years; range, 26-86 [standard deviation, SD±18] years). In the BAM group of functioning AVF, n=30, the total number of procedures was 125 (range, 1-8, average 4). The overall average duration to maturation of the AVF was 119days (SD±84days) and 146days (SD±157 days) P=0.73, for BAM and non-BAM, respectively. These preliminary data suggest the role of BAM did not decrease maturation times of AVF and that BAM warrants further scrutiny before further adoption.

Recipient-derived angiogenesis with short term immunosuppression increases bone remodeling in bone vascularized composite allotransplantation: A pilot study in a swine tibial defect model.

Current vascularized composite allotransplantation (VCA) transplantation protocols rely upon life-long immune modulation to maintain tissue perfusion. Alternatively, bone-only VCA viability may be maintained in small animal models using surgical angiogenesis from implanted autogenous vessels to develop a neoangiogenic bone circulation that will not be rejected. This study tests the method's efficacy in a large animal model as a bridge to clinical practice, quantifying the remodeling and mechanical properties of porcine tibial VCAs. A segmental tibial defect was reconstructed in Yucatan miniature swine by transplantation of a matched tibia segment from an immunologically mismatched donor. Microsurgical repair of nutrient vessels was performed in all pigs, with simultaneous intramedullary placement of an autogenous arteriovenous (AV) bundle in Group 2. Group 1 served as a no-angiogenesis control. All received 2 weeks of immunosuppression. After 16 weeks, micro-CT and histomorphometric analyses were used to evaluate healing and remodeling. Axial compression and nanoindentation studies evaluated bone mechanical properties. Micro-CT analysis demonstrated significantly more new bone formation and bone remodeling at the distal allotransplant/recipient junction and on the endosteal surfaces of Group 2 tibias (p = 0.03). Elastic modulus and hardness were not adversely affected by angiogenesis. The combination of 2 weeks of immunosuppression and autogenous AV-bundle implantation within a microsurgically transplanted tibial allotransplant permitted long-term allotransplant survival over the study period of 16 weeks in this large animal model. Angiogenesis increased bone formation and remodeling without adverse mechanical effects. The method may allow future composite-tissue allotransplantation of bone without the risks associated with long-term immunosuppression. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1242-1249, 2017.

PC134. Incidence of Central Venous Stenosis and Other Adverse Outcomes Related to Placement of Tunneled Hemodialysis Catheters During Maturation of Autogenous Arteriovenous Fistulas

PC134. Incidence of Central Venous Stenosis and Other Adverse Outcomes Related to Placement of Tunneled Hemodialysis Catheters During Maturation of Autogenous Arteriovenous Fistulas

Randomized Trial Comparing the Primary Patency following Cutting Versus High-Pressure Balloon Angioplasty for Treatment of de Novo Venous Stenoses in Hemodialysis Arteriovenous Fistulae

PurposeA single-center randomized clinical trial was performed to compare postinterventional primary patency rates achieved by cutting balloon angioplasty and high-pressure balloon angioplasty in the treatment of de novo stenoses within autogenous arteriovenous (AV) fistulae for hemodialysis. Materials and MethodsForty-eight patients undergoing their first angioplasty were prospectively randomized to undergo angioplasty with a cutting balloon or high-pressure balloon 4–8 mm in diameter because cutting balloons larger than 8 mm are not available. Nine patients were excluded after angiography, with seven requiring balloons larger than 8 mm. In the remaining 39 patients, there were 42 stenoses in the following regions: juxtaanastomotic (38%), perianstomotic (38%), midcephalic (9%), and cephalic arch (14%). Patients in the cutting balloon group were younger (mean age difference, 9 y; P = .04), but other demographic variables were comparable (range, P = .08–.89). The mean follow-up period was 8.5 mo (range, 24 d to 32 mo). Kaplan–Meier analysis was used to compare duration of patency. Mann–Whitney rank-sum t test and χ2/Fisher exact tests were used to compare continuous and categoric variables, respectively. ResultsTechnical success was achieved in all 39 patients. At 3, 6, and 12 months, the postinterventional primary patency rates for the cutting balloon group were 61.1% (95% confidence interval [CI], 35.75%–82.70%), 27.7% (95% CI, 9.69%–53.48%), and 11.1% (95% CI, 1.38%–34.71%), respectively, compared with 70.0% (95% CI, 45.72%–88.11%), 42.1% (95% CI, 20.25%–66.50%), and 26.3% (95% CI, 9.15%–51.20%), respectively, for the high-pressure balloon group (P < .3 at each interval). ConclusionsCompared with high-pressure balloon angioplasty, cutting balloon angioplasty does not improve postinterventional primary patency of de novo stenotic lesions in autogenous arteriovenous fistulae.

The use of the early cannulation prosthetic graft (Acuseal™) for angioaccess for haemodialysis.

Autogenous arteriovenous (AV) accesses are the preferred choice for the delivery of haemodialysis (HD). With an increase in the prevalence of end-stage renal disease and in the life expectancy of these patients, the quality and availability of superficial vessels can be limited and reduced with time. The use of prosthetic AV accesses may therefore become necessary for the delivery of HD. A new early cannulation vascular prosthesis (GORE® ACUSEAL Vascular Graft) has been introduced, developed to hinder suture line and cannulation needle bleeding. The authors report their experience with this new conduit at a London teaching hospital. Between May 2011 and June 2013, 52 patients underwent 55 procedures where the ACUSEAL® prosthetic AV access was utilized to facilitate HD. The majority of procedures involved the placement of prosthetic brachio-axillary accesses or prosthetic axillo-axillary chest accesses. The 1-year primary and secondary patency was found to be 46% and 61%, respectively. Successful cannulation of the newly placed AV access was performed with 24 hours of surgery in 40 patients (73%). Tunnelled vascular catheters were required in only 10 (18%) patients. Six (11%) of the patients in the study suffered early complications, and 9 (16%) patients developed AV access infection. These results show that, while providing patency results that compare favourably to those published for other types of regular prosthetic accesses, the conduits are amenable to very early cannulation with few cannulation-related complications. This leads to a dramatic reduction in the need for temporary or tunnelled catheters.

Surgeon's Intraoperative Assessments During Autogenous Arteriovenous Fistula Creation Strongly Correlate With Early Fistula Thrombosis

Surgeon's Intraoperative Assessments During Autogenous Arteriovenous Fistula Creation Strongly Correlate With Early Fistula Thrombosis

Aneurysm formation and infection in AV prosthesis.

In contrast to autogenous arteriovenous (AV) fistulae where true aneurysms are the most frequent type, aneurysms in prosthetic AV grafts are mostly false aneurysms and less frequently anastomotic ones. Indications for repair comprise false aneurysms exceeding twofold the graft diameter, those with rapid enlargement or with skin thinning or erosion, the ruptured, those causing pain or severely limiting the cannulable area and the infected ones. They can be managed either with conventional surgery or with endovascular techniques; However, conventional surgery represents the current standard treatment consisting of either aneurysm resection and interposition graft in situ or resection/exclusion and bypass via a new route to avoid a potentially contaminated area.

Six Cases of Ruptured Autogenous Arteriovenous Shunt Caused by Bacterial Infection

Six Cases of Ruptured Autogenous Arteriovenous Shunt Caused by Bacterial Infection

Risk Factors Predicting the Successful Function and Use of Autogenous Arteriovenous Fistulae for Hemodialysis

For patients with end-stage renal failure hemodialysis with an autogenous arteriovenous fistula (AVF) has proven to be the ideal vascular access. The aim of this study is to discover potential predictors of a well-functioning hemodialysis fistula. From December 2009 to March 2011, 80 patients undergoing first time AVF creation were enrolled in our retrospective study. We analyzed pre- and postoperative vessel diameters and flow characteristics gained by duplex ultrasonography (DUS) and intraoperative ultrasound transit-time flow measurements regarding intraoperative blood flow and pulsatility index (PI). Follow-up was defined until the end of the first month with regular hemodialysis, 10 weeks after AVF creation. We performed statistical analyses by employing Spearman correlation, t test, analysis of variance, χ2 test, and receiver operating characteristics (ROC). At the end of the follow-up, 62 patients (78%) featured functioning AVFs and 18 patients (22%) featured nonfunctioning AVFs. Factors influencing AVF function were radial artery diameter (χ2 = 5.23, p = 0.02), intraoperative flow (χ2 = 7.09, p = 0.01), intraoperative PI (χ2 = 6.5, p = 0.01), and postoperative flow (χ2 = 16.29, p = 0.01). According to the ROC analyses, we could develop cut-off values for predicting an ideal AVF function: radial artery diameter more than 2.3 mm, cephalic vein diameter more than 2.7 mm, intraoperative mean flow more than 113 mL/min, PI less than 1.4, and postoperative mean flow more than 160 mL/min. Intraoperative ultrasound transit-time flow measurements gained at surgery and postoperative follow-up with DUS can help identify AVFs that are unlikely to function and therefore need early intervention.

Ultrasound-Guided Angioplasty of Autogenous Arteriovenous Fistulas in the Office Setting

Ultrasound-Guided Angioplasty of Autogenous Arteriovenous Fistulas in the Office Setting

Long-term Results of Stent-graft Placement to Treat Central Venous Stenosis and Occlusion in Hemodialysis Patients with Arteriovenous Fistulas

Purpose To determine the effectiveness of stent-grafts for the treatment of central venous disease in hemodialysis patients with functioning arteriovenous (AV) fistulas. Materials and Methods Between October 2004 and March 2010, 42 VIABAHN stent-grafts were deployed in central veins of 30 patients (16 men, 14 women; mean age 60 y) with functioning AV fistulas and central venous disease that did not respond to percutaneous transluminal angioplasty (PTA). Eighteen patients had central vein stenosis and 12 had occlusion. Previous PTA and/or bare metal stent placement had been performed in 23 patients (77%). Surveillance was carried out at 3, 6, 9, 12, 18, and 24 months with diagnostic fistulography. The mean follow-up was 705 days (range, 66–1,645 d). Statistical analysis included Kaplan–Meier and log-rank studies. Results Technical success rate was 100%. Primary patency rates were 97%, 81%, 67%, and 45% at 3, 6, 12, and 24 months, respectively. Primary assisted patency rates were 100%, 100%, 80%, and 75% at 3, 6, 12, and 24 months, respectively. Patients without previous procedures had significantly shorter times to repeat intervention ( P = .018) than those who had undergone PTA or bare metal stent placement previously. Patients with occlusive lesions had a significantly shorter primary patency interval ( P = .05) than patients with stenoses. Occluded veins were more likely to require further stent-grafts ( P = .02). Twelve patients required further stent-grafts to maintain patency. There was one minor complication. Conclusions Stent-graft placement to treat central venous disease in hemodialysis patients with autogenous AV fistulas is safe and effective if PTA fails to maintain luminal patency.

Balloon Angioplasty to Facilitate Autogenous Arteriovenous Access Maturation: A New Paradigm for Upgrading Small-Caliber Veins, Improved Function, and Surveillance

Balloon angioplasty maturation is emerging as an important method to increase utilization and improve function of autogenous arteriovenous hemodialysis accesses (AVFs). Through the sequential dilation of small veins, large-diameter AVFs can be created with the inherent benefits of easier cannulation, greater overall surface area, improved patency, and fewer complications. A usable AVF can be created in a shorter amount of time, decreasing the need for dialysis catheters. In addition, selective angioplasty of the AVF inflow and outflow can facilitate improved flow rates and increase access longevity. Our approach, including primary balloon angioplasty during AVF creation, sequential balloon angioplasty maturation, and surveillance fistulagrams will be presented.

Evaluation of Expanded Polytetrafluoroethylene–covered Stents for the Treatment of Venous Outflow Stenosis in Hemodialysis Access Grafts

Purpose To investigate the use of an expanded polytetrafluoroethylene–coated nitinol stent-graft in patients with failing hemodialysis access circuits and compare grafts with and without a heparin-coated surface. Materials and Methods A single-institution retrospective review of 16 patients (average age, 55 years; seven men) treated for hemodialysis access circuit stenoses was performed. Patients had a prosthetic arteriovenous (AV) graft ( n = 10) or autogenous AV fistula ( n = 6), all with clinically relevant access stenoses that were refractory to angioplasty alone; 10 patients also had access circuit thrombosis at the time of treatment. Stents were placed in the basilic ( n = 4), brachial ( n = 7), cephalic ( n = 4), and femoral ( n = 1) veins. Study endpoints included primary treatment area patency, primary circuit patency, primary assisted circuit patency, and secondary circuit patency, followed to a maximum of 6 months. Results Primary treatment area patency rates at 30 days and 180 days were 75% and 31%, respectively. Secondary patency rates at the same time points were 88% and 68%, respectively. Mean primary treatment area patency was 93 days. Thrombosis was a major cause of failure, occurring in seven of 11 cases of primary treatment area patency loss. Subgroup analysis demonstrated that the heparin-coated configuration ( n = 7) showed a 6-month primary patency rate of 57%, compared with 11% for the stent-grafts without heparin bonding ( n = 9; P = .06). Conclusions Overall, the majority of deployed stent-grafts lost primary patency within 6 months, with thrombosis a major cause of failure. However, the addition of a heparin-coated surface appeared to improve results in these otherwise treatment-refractory access circuits.