Midterm outcomes of arteriovenous fistula aneurysm repair with simultaneous inflow revision or outflow tract revascularization.

OBJECTIVE: The aim of this study was to investigate the 2-year outcomes of extensive revisions aimed at simultaneously addressing arteriovenous fistula (AVF) aneurysms, outflow stenosis, and/or high flow volumes. METHODS: This was a retrospective cohort study in a tertiary referral center. The study population comprised hemodialysis patients with aneurysmal AVFs requiring revision. Subjects were eligible if they were ≥18 years of age and had aneurysm repair associated with inflow revision or treatment of outflow lesions. Patients were followed-up for a minimum of 2 years, and the primary outcome measure was cumulative patency. RESULTS: Our cohort comprised 93 patients with a mean age of 56 ± 12 years. The most frequent access type was brachiocephalic fistula (61%), and the median access age at the time of revision was 66 months (interquartile range, 46-93 months). The median access flow volume was 2300 ml/min (interquartile range, 1281-2900), and 31 subjects (33%) presented aneurysms associated with both high flow and venous obstruction. Aneurysm repair consisted of aneurysmorraphy in the overwhelming majority (95%). Inflow revision was performed in a total of 49 cases (53%), and outflow tract obstruction was treated in 71 patients (72%), with 27 patients (29%) receiving a simultaneous 3-component revision. At 2 years, the primary, primary assisted, and cumulative patencies were 60% ± 1%, 91% ± 3%, and 94% ± 3%, respectively. The most frequent indication for first-time reinterventions was outflow tract stenosis (24%). Aneurysm recurrence was observed in 13 subjects (14%) during the entire follow-up and was responsible for reinterventions in seven of them (8%), with a 2-year freedom from aneurysm-related reintervention rate of 95% ± 3%. CONCLUSIONS: Extensive AVF revision with simultaneous aneurysm repair, inflow revision, and outflow tract revascularization is feasible, safe, and associated with favorable 2-year patency rates.

Downregulation of the endothelial histone demethylase JMJD3 is associated with neointimal hyperplasia of arteriovenous fistulas in kidney failure.

Jumonji domain-containing protein-3 (JMJD3), a histone H3 lysine 27 (H3K27) demethylase, promotes endothelial regeneration, but its function in neointimal hyperplasia (NIH) of arteriovenous fistulas (AVFs) has not been explored. In this study, we examined the contribution of endothelial JMJD3 to NIH of AVFs and the mechanisms underlying JMJD3 expression during kidney failure. We found that endothelial JMJD3 expression was negatively associated with NIH of AVFs in patients with kidney failure. JMJD3 expression in endothelial cells (ECs) was also downregulated in the vasculature of chronic kidney disease (CKD) mice. In addition, specific knockout of endothelial JMJD3 delayed EC regeneration, enhanced endothelial mesenchymal transition, impaired endothelial barrier function as determined by increased Evans blue staining and inflammatory cell infiltration, and accelerated neointima formation in AVFs created by venous end to arterial side anastomosis in CKD mice. Mechanistically, JMJD3 expression was downregulated via binding of transforming growth factor beta 1-mediated Hes family transcription factor Hes1 to its gene promoter. Knockdown of JMJD3 enhanced H3K27 methylation, thereby inhibiting transcriptional activity at promoters of EC markers and reducing migration and proliferation of ECs. Furthermore, knockdown of endothelial JMJD3 decreased endothelial nitric oxide synthase expression and nitric oxide production, leading to the proliferation of vascular smooth muscle cells. In conclusion, we demonstrate that decreased expression of endothelial JMJD3 impairs EC regeneration and function and accelerates neointima formation in AVFs. We propose increasing the expression of endothelial JMJD3 could represent a new strategy for preventing endothelial dysfunction, attenuating NIH, and improving AVF patency in patients with kidney disease.

Dynamic, Time-Resolved CT Angiography After EVAR: A Quantitative Approach to Accurately Characterize Aortic Endoleak Type and Identify Inflow Vessels.

PURPOSE: Our purpose was to study the accuracy of dynamic computed tomography angiography (d-CTA) in characterizing endoleak type, inflow vessels as compared with digital subtraction angiography (DSA) using qualitative and quantitative analysis. METHODS: Between March 2019 and January 2021, all patients who underwent d-CTA imaging after EVAR were retrospectively reviewed. Two blinded independent reviewers qualitatively reviewed d-CTA and DSA images. Quantitative region of interest (ROI) analysis was performed by measuring time-resolved contrast enhancement within the aorta and endoleak lesion(s) in the aneurysm sac. Differences between time-to-peak enhancement (Δ TTP) across different ROIs were quantified. RESULTS: A total of 48 patients underwent d-CTA during the study period, of whom 24 patients had abdominal EVAR and DSA imaging for comparison. Qualitative review of DSA imaging showed type I (n=4), type II (n=16), and type III (n=2) and no endoleak (n=2). In 23 of 24 patients (95.8%), d-CTA findings correlated with DSA findings for endoleak type. One patient had a type III endoleak that was demonstrated only in d-CTA (arising from defect in polymer sealing ring of Ovation stent graft) imaging. In type II endoleak cases, d-CTA identified more inflow vessels than DSA imaging (33 vs 21 vessels, p=0.010). Quantitative analysis showed mean (±SD) Δ TTP values for type I endoleak as 1.8 (±1.8) seconds, type II as 9.6 (±3.5) seconds, and for type III endoleak as 5.6 (±1.3) seconds. CONCLUSION: Dynamic CTA can accurately characterize aortic endoleak type, inflow vessels as compared with DSA imaging. Quantitative parameters such as Δ TTP enhancement can help better differentiate endoleak types and provide an objective approach to endoleak diagnosis.

Dynamic Computed Tomography Angiography is More Accurate in Diagnosing Endoleaks than Standard Triphasic Computed Tomography Angiography and Enables Targeted Embolization.

BACKGROUND: The primary objective was to compare the accuracy of dynamic computed tomography (CT) angiography (d-CTA) with standardized triphasic contrast enhanced CT angiography (t-CTA) in diagnosing endoleak type after endovascular aortic repair (EVAR) using digital subtraction angiography (DSA) as reference standard. The secondary objective was to study the impact of d-CTA on image fusion-guided endoleak embolization. METHODS: A retrospective review of patients who underwent d-CTA imaging after EVAR between March 2019 and July 2021 was performed. Deidentified images were independently reviewed by two-two blinded readers to document endoleak type and target vessels. An impact of d-CTA-guided embolization was evaluated by a number of planning angiograms, radiation exposure, and accuracy of target vessel overlay. RESULTS: During the study period, 52 patients underwent d-CTA and 19 had all 3 modalities available for analysis. DSA imaging confirmed 4 (21.0%) type-I, 14 (73.7%) type-II, and 1 (5.3%) type-III endoleak. Findings from d-CTA matched with DSA in 19/19 cases (100%), whereas t-CTA matched in 14/19 cases (73.7%). In type-II endoleaks, the number of target vessels identified by d-CTA, t-CTA, and DSA were 23, 17, and 16, respectively. Mean dose-length product from d-CTA and t-CTA was 1,445 ± 551 and 1,612 ± 530 mGy × cm (P = 0.26). Nine patients underwent d-CTA-guided type-II endoleak embolization, using a median of 1 (range: 1-4) planning angiogram before embolization using 21.6 (± 8.7)% of total procedural radiation dose. Target vessel overlay was accurate in 9/9 (100%) cases. CONCLUSIONS: Dynamic, time-resolved CTA is more accurate compared to standardized triphasic contrast enhanced CTA in diagnosing endoleak type after EVAR. In type-II endoleak, d-CTA better identified target vessels and enabled safe, targeted embolization.

Vasculink iPhone Application and Risk Prediction Model for Groin Complication in Vascular Surgery.

BACKGROUND: Postoperative groin complication is a common cause of morbidity in vascular surgery. Prophylactic wound adjuncts addressing this issue have been shown to reduce complications in high-risk patients, but their widespread implementation is limited by their high cost. This study introduces a risk prediction model for patients at a high risk for groin complication which can be accessed through the iPhone application, Vasculink. METHODS: A literature search identified risk prediction models for groin complication in vascular surgery. Odds ratios of risk factors that were present in at least 2 published models were calculated with a pooled effect size. The weighted risk for each factor was used to create our model and a cutoff point defining high risk patients was chosen. The initial model was assessed and validated using a split-sample methodology on a cohort identified via a retrospective chart review of all patients undergoing open vascular surgery at our institution between 2017 and 2020. Model performance was assessed using the C-statistic. RESULTS: Risk factors included in our model were female gender, body mass index ≥28 kg/m2, ever-smoker, reoperation, use of prosthetic, emergency, and end-stage renal disease. Of 216 patients, 131 were at a high risk. The overall groin complication rate was 43%, and specific complication rates were 27% infection, 14.8% seroma, and 6.9% hematoma. Our model's sensitivity and specificity were 92.47% and 60.98%, respectively. The C-statistic is 0.768. CONCLUSIONS: By using risk factors identified in the literature we have been able to establish a highly sensitive risk prediction model for groin complication following open vascular surgery. By incorporating our model into an iPhone application, Vasculink, we hope to facilitate preoperative decision making regarding the use of prophylactic wound adjuncts.

Notch signaling in bone marrow-derived FSP-1 cells initiates neointima formation in arteriovenous fistulas.

Neointima formation is a major contributor to arteriovenous fistula (AVF) failure. We have previously shown that activation of the Notch signaling pathway contributes to neointima formation by promoting the migration of vascular smooth muscle cells (VSMCs) into the venous anastomosis. In the current study we investigated the mechanisms underlying the dedifferentiation and migration of VSMCs, and in particular the role of bone marrow-derived fibroblast specific protein 1 (FSP-1)+ cells, another cell type found in models of vascular injury. Using VSMC-specific reporter mice, we found that most of the VSMCs participating in AVF neointima formation originated from dedifferentiated VSMCs. We also observed infiltration of bone marrow-derived FSP-1+ cells into the arterial anastomosis where they could interact with VSMCs. In vitro, conditioned media from FSP-1+ cells stimulated VSMC proliferation and phenotype switching. Activated Notch signaling transformed FSP-1+ cells into type I macrophages and stimulated secretion of cytokines and growth factors. Pretreatment with a Notch inhibitor or knockout of the canonical downstream factor RBP-Jκ in bone marrow-derived FSP1+ cells decreased FSP1+ cell infiltration into murine AVFs, attenuating VSMC dedifferentiation and neointima formation. Our results suggest that targeting Notch signaling could provide a new therapeutic strategy to improve AVF patency.

A randomized trial of vonapanitase (PATENCY-1) to promote radiocephalic fistula patency and use for hemodialysis.

OBJECTIVE: Arteriovenous fistulas created in patients with chronic kidney disease often lose patency and fail to become usable. This prospective trial evaluated the efficacy of vonapanitase, a recombinant human elastase, in promoting radiocephalic fistula patency and use for hemodialysis. METHODS: PATENCY-1 was a double-blind, placebo-controlled trial that enrolled 349 patients on or approaching hemodialysis and being evaluated for radiocephalic arteriovenous fistula creation. Of these, 313 were randomized and 311 treated. Patients were assigned to vonapanitase (n = 210) or placebo (n = 103). The study drug solution was applied topically to the artery and vein for 10 minutes immediately after fistula creation. The primary and secondary end points were primary patency (time to first thrombosis or corrective procedure) and secondary patency (time to abandonment). Tertiary end points included use of the fistula for hemodialysis, fistula maturation by ultrasound, and procedure rates. RESULTS: The Kaplan-Meier estimates of 12-month primary patency were 42% (95% confidence interval [CI], 35-49) and 31% (95% CI, 21-42) for vonapanitase and placebo (P = .25). The Kaplan-Meier estimates of 12-month secondary patency were 74% (95% CI, 68-80) and 61% (95% CI, 51-71) for vonapanitase and placebo (P = .048). The proportions of vonapanitase and placebo patients were 39% and 25% (P = .035) with unassisted use for hemodialysis and 64% and 44% (P = .006) with unassisted plus assisted use. CONCLUSIONS: Vonapanitase treatment did not significantly improve primary patency but was associated with increased secondary patency and use for hemodialysis. Further research is needed to evaluate these end points.

Bioengineered human acellular vessels for dialysis access in patients with end-stage renal disease: two phase 2 single-arm trials.

BACKGROUND: For patients with end-stage renal disease who are not candidates for fistula, dialysis access grafts are the best option for chronic haemodialysis. However, polytetrafluoroethylene arteriovenous grafts are prone to thrombosis, infection, and intimal hyperplasia at the venous anastomosis. We developed and tested a bioengineered human acellular vessel as a potential solution to these limitations in dialysis access. METHODS: We did two single-arm phase 2 trials at six centres in the USA and Poland. We enrolled adults with end-stage renal disease. A novel bioengineered human acellular vessel was implanted into the arms of patients for haemodialysis access. Primary endpoints were safety (freedom from immune response or infection, aneurysm, or mechanical failure, and incidence of adverse events), and efficacy as assessed by primary, primary assisted, and secondary patencies at 6 months. All patients were followed up for at least 1 year, or had a censoring event. These trials are registered with ClinicalTrials.gov, NCT01744418 and NCT01840956. FINDINGS: Human acellular vessels were implanted into 60 patients. Mean follow-up was 16 months (SD 7·6). One vessel became infected during 82 patient-years of follow-up. The vessels had no dilatation and rarely had post-cannulation bleeding. At 6 months, 63% (95% CI 47-72) of patients had primary patency, 73% (57-81) had primary assisted patency, and 97% (85-98) had secondary patency, with most loss of primary patency because of thrombosis. At 12 months, 28% (17-40) had primary patency, 38% (26-51) had primary assisted patency, and 89% (74-93) had secondary patency. INTERPRETATION: Bioengineered human acellular vessels seem to provide safe and functional haemodialysis access, and warrant further study in randomised controlled trials. FUNDING: Humacyte and US National Institutes of Health.

Arteriovenous fistula patency in the 3 years following vonapanitase and placebo treatment.

OBJECTIVE: This study explored the long-term outcomes of arteriovenous fistulas treated with vonapanitase (recombinant human elastase) at the time of surgical creation. METHODS: This was a randomized, double-blind, placebo-controlled trial of 151 patients undergoing radiocephalic or brachiocephalic arteriovenous fistula creation who were randomized equally to placebo, vonapanitase 10 µg, or vonapanitase 30 µg. The results after 1 year of follow-up were previously reported. The current analysis occurred when the last patient treated was observed for 3 years. For the current analysis, the primary end point was primary patency; the secondary end points included secondary patency, use of the fistula for hemodialysis, and rate of procedures to restore or to maintain patency. RESULTS: There was no significant difference in the risk of primary patency loss with vonapanitase 10 µg or 30 µg vs placebo. When seven initial patency loss events related to cephalic arch and central vein balloon angioplasty were excluded, the risk of patency loss was reduced with vonapanitase overall (hazard ratio [HR], 0.63; P = .049) and 30 µg (HR, 0.51; P = .03). In patients with radiocephalic fistulas (n = 67), the risks of primary and secondary patency loss were reduced with 30 µg (HR, 0.37 [P = .02] and 0.24 [P = .046], respectively). The rate of procedures to restore or to maintain fistula patency was reduced with 30 µg vs placebo (0.23 vs 0.72 procedure days/patient/year; P = .03) and also reduced in patients with radiocephalic fistulas with 30 µg vs placebo (0.17 vs 0.85 procedure days/patient/year; P = .048). CONCLUSIONS: In this study, vonapanitase did not significantly improve primary patency in the primary analysis but did significantly improve primary patency in an analysis that excluded patency loss due to cephalic arch and central vein balloon angioplasty. In patients with radiocephalic fistulas, 30 µg significantly improved primary and secondary patency. Vonapanitase 30 µg decreased the rate of procedures to restore or to maintain patency in the analysis that included all patients and in the subset with radiocephalic fistulas.

Establishing patient-specific criteria for selecting the optimal upper extremity vascular access procedure.

OBJECTIVE: The Kidney Disease Outcome Quality Initiative and Fistula First Breakthrough Initiative call for the indiscriminate creation of arteriovenous fistulas (AVFs) over arteriovenous grafts (AVGs) without providing patient-specific criteria for vascular access selection. Although the U.S. AVF rate has increased dramatically, several reports have found that this singular focus on increasing AVFs has resulted in increased AVF nonmaturation/early failure and a high prevalence of catheter dependence. The objective of this study was to determine the appropriateness of vascular access procedures in clinical scenarios constructed with combinations of relevant factors potentially influencing outcomes. METHODS: The RAND/UCLA Appropriateness Method was used. Accordingly, a comprehensive literature search was performed and a synthesis of results compiled. The RAND/UCLA Appropriateness Method was applied to 2088 AVF and 1728 AVG clinical scenarios with varying patient characteristics. Eleven international vascular access experts rated the appropriateness of each scenario in two rounds. On the basis of the distribution of the panelists' scores, each scenario was determined to be appropriate, inappropriate, or indeterminate. RESULTS: Panelists achieved agreement in 2964 (77.7%) scenarios; 860 (41%) AVF and 588 (34%) AVG scenarios were scored appropriate, 686 (33%) AVF and 480 (28%) AVG scenarios were scored inappropriate, and 542 (26%) AVF and 660 (38%) AVG scenarios were indeterminate. Younger age, larger outflow vein diameter, normal or obese body mass index (vs morbidly obese), larger inflow artery diameter, and higher patient functional status were associated with appropriateness of AVF creation. Older age, dialysis dependence, and smaller vein size were associated with appropriateness of AVG creation. Gender, diabetes, and coronary artery disease were not associated with AVF or AVG appropriateness. Dialysis status was not associated with AVF appropriateness. Body mass index and functional status were not associated with AVG appropriateness. To simulate the surgeon's decision-making, scenarios were combined to create situations with the same patient characteristics and both AVF and AVG options for access. Of these 864 clinical situations, 311 (36%) were rated appropriate for AVG but inappropriate or indeterminate for AVF. CONCLUSIONS: The results of this study indicate that patient-specific situations exist wherein AVG is as appropriate as or more appropriate than AVF. These results provide patient-specific recommendations for clinicians to optimize vascular access selection criteria, to standardize care, and to inform payers and policy. Indeterminate scenarios will guide future research.

Superior Vena Cava Reconstruction Using Femoropopliteal Vein as a Panel Graft.

There has been an increase in superior vena cava (SVC) syndrome secondary to the growing use of indwelling catheters and pacemaker wire insertions. These 2 factors can account up to 74% cases of benign SVC syndrome. Endovascular therapy is considered the first line of treatment. Surgery is an excellent option and is generally reserved for SVC syndrome not amenable to traditional endovascular procedures. We report a case of central venous reconstruction including an SVC reconstruction using the femoropopliteal vein as a panel graft in a patient with SVC syndrome due to pacemaker wires who failed multiple endovascular interventions.

Axillary Artery to Right Atrial Graft for Dialysis Access Using an Autologous Femoropopliteal Vein.

Patients with prolonged history of central venous catheters can develop central venous occlusion. We report the creation of an axillary artery to right atrial graft using the femoropopliteal vein (FPV) for dialysis access in a patient with end-stage renal disease on hemodialysis with history of central venous occlusion. The patient had previously developed steal syndrome following a right brachial artery to right atrial polytetrafluoroethylene graft requiring revision to a left axillary artery inflow which subsequently thrombosed. This is the first report of using an autologous FPV conduit to the right atrium for dialysis.

Revision using distal inflow is a safe and effective treatment for ischemic steal syndrome and pathologic high flow after access creation.

OBJECTIVE: Ischemic steal syndrome (ISS) and pathologic high flow (HF) are a complications after hemodialysis access creation. Their management is complex and varied with most requiring surgical revision for correction of symptoms. Revision using distal inflow (RUDI) has been described in small series for the treatment of ISS. We present our experience with RUDI for the treatment of ISS and pathologic HF. METHODS: We retrospectively reviewed consecutive patients who underwent RUDI for ISS from April, 2010 to March, 2014. Data collection included demographic characteristics, medical histories, subsequent procedures, volume flows, access usage, limb salvage, and patient survival. RESULTS: We performed 29 RUDI procedures in 28 patients (16 women, 12 men). Indications for surgery were pathologic HF in 13 and ISS in 19. Ten percent had previous banding for ISS or HF. Sixty-nine percent of patients had a history of diabetes. Fifty-two percent had a history of atherosclerotic disease. Mean time to intervention from creation was 40 months (range, 6-88 months). Accesses included 1 upper arm graft and 27 brachial artery-based fistulas. Outflow included 25 cephalic veins and 3 basilic veins. Distalization targets were 19 radial arteries and 10 ulnar arteries. Mean flow reduction was 1191 mL/min. Primary assisted patency at 1 year was 74%. Secondary patency at 1 year was 87%. A single access was ligated for continued heart failure after RUDI. ISS symptom resolution was reported as complete in 69% and partial in 31%. CONCLUSIONS: RUDI is an effective and durable treatment of ISS and HF comparable with reported experiences with distal revascularization-interval ligation, proximalization of the arterial inflow, and banding. Patient selection is key for optimizing relief of symptoms and maintaining use of the access.

Evaluating and treating venous outflow stenoses is necessary for the successful open surgical treatment of arteriovenous fistula aneurysms.

BACKGROUND: Arteriovenous fistula (AVF) aneurysms (AVFAs) can lead to skin erosion, bleeding, difficult access while on hemodialysis, and poor cosmetic appearance. We reviewed our experience in treating patients with aneurysmal dilatation of their AVF. METHODS: We reviewed clinical data of 48 patients (37 men; overall mean age, 55 years; range, 28-85 years) with an AVFA who underwent treatment during a 30-month period. Relevant clinical variables and treatment outcomes were analyzed. RESULTS: All patients underwent a fistulogram, and 90% required percutaneous angioplasty to improve outflow. Fifty-six percent of patients had one stenotic outflow lesion, and 44% had at least two tandem outflow stenoses that required treatment. Open repair with aneurysmorrhaphy was performed in one stage in 64% of patients and in two stages in 36%. A tunneled hemodialysis catheter was required in 11 patients (23%) until the surgically repaired AVF was ready for use again, comprising 10 patients treated with single-stage surgery and only one patient in the staged group. All AVFAs were effectively treated, and patients were able to maintain functional use of their access when healed. CONCLUSIONS: There is a high association of venous outflow stenoses and AVFA. Comprehensive therapy should encompass treatment of any venous outflow stenoses before open AVFA repair. A two-stage repair may decrease tunneled hemodialysis catheter use in patients with multiple aneurysms.

Early Experience With a Novel Hybrid Vascular Graft for Hemodialysis Access Creation in Patients With Disadvantaged Anatomy.

PURPOSE: To describe the use of the Hybrid vascular graft in disadvantaged anatomy for hemodialysis access creation and compare outcomes to standard-wall polytetrafluoroethylene (PTFE) grafts. METHODS: In a retrospective analysis, 25 patients (mean age 65±14 years; 13 men) who received the Hybrid graft were compared with 35 contemporaneous patients (mean age 63±12 years; 20 men) who received a standard PTFE graft for hemodialysis access over a 2-year period. Criteria for Hybrid graft placement were (1) exhausted or inadequate peripheral veins for arteriovenous fistula (AVF) creation and concomitant small target veins that precluded conventional PTFE graft placement, (2) previous graft anastomosis or a stent in the venous target at the level of the axilla, or (3) failed brachial-basilic or brachial-brachial upper arm transposition AVF with a small target vein at the axilla. Efficacy, anatomic and clinical considerations, and technique were reviewed; patency rates, complications, and reinterventions were examined. RESULTS: Technical success was achieved in all cases, and all grafts were usable for hemodialysis. Seven of 25 Hybrid patients required stent-graft extensions and 3 patients required angioplasty to improve venous outflow at the time of Hybrid graft insertion. Three of 35 standard PTFE graft patients required angioplasty to improve venous outflow at the time of graft insertion. There was no perioperative mortality or procedure-related morbidity in either group. Median follow-up was 21 months. The patient survival estimate was 66% at 2 years. Estimated primary patency (24% vs 18%, p>0.05), assisted primary patency (34% vs 28%; p>0.05), and secondary patency rates (40% vs 38%, p≥0.05) at 24 months were equivalent for Hybrid vs PTFE grafts, respectively. Venous hypertension was not a complication following Hybrid graft implantation but was seen in 2 patients with the standard PTFE graft. CONCLUSION: The Hybrid graft offers a safe, technically effective alternative for patients with disadvantaged anatomy requiring hemodialysis access and has comparable outcomes to standard PTFE grafts. Further clinical experience and long-term data are required for determining the proper utility of this device in chronic dialysis-dependent patients.

Right Brachial to Atrial Xenograft Conduit for Hemodialysis Access: A Case Report.

Biologic grafts may be a viable alternative to their prosthetic counterparts in the patients who have exhausted conventional access alternatives given their superior patency rates and possible resilience to infection. This is a case report of a 66-year-old woman with end-stage renal disease and human immunodeficiency virus who has had multiple failed peripheral arteriovenous (AV) fistulas and grafts as well as inferior vena caval obstruction necessitating a transhepatic catheter for hemodialysis (HD). Given the patient's comorbidities and history, a right brachial artery-to-atrial conduit was created for long-term access. Biologic bovine carotid artery was used given its decreased susceptibility to infection and favorable patency rates. The AV access continues to function at 3.5-year follow-up and remains her primary means of HD. We present this novel use of a biologic graft as an option in patients with central venous obstruction and high risk of infection requiring exotic dialysis access.

Human type I pancreatic elastase treatment of arteriovenous fistulas in patients with chronic kidney disease.

OBJECTIVE: This study explored the safety and efficacy of recombinant type I pancreatic elastase (PRT-201) topically applied once to the external surface of an arteriovenous fistula. METHODS: This was a randomized, double-blind, placebo-controlled trial. Adults with kidney disease undergoing creation of a radiocephalic fistula (RCF) or brachiocephalic fistula were randomized to treatment with placebo (n = 51), PRT-201 at 10 µg (n = 51), or PRT-201 at 30 µg (n = 49). The primary efficacy measure was unassisted primary patency (PP) over 1 year. Secondary efficacy measures were secondary patency (SP), unassisted maturation by ultrasound interrogation, use for hemodialysis, and hemodynamically significant lumen stenosis. RESULTS: Median PP was 224 days for placebo and >365 days for the PRT-201 groups. At 1 year, 45%, 54%, and 53% of placebo, 10-µg, and 30-µg patients retained PP. The risk of PP loss was nonsignificantly reduced for 10 µg (hazard ratio [HR], 0.69; P = .19) and 30 µg (HR, 0.67; P = .17) vs placebo. In the subset (44% of patients) with a RCF, the median PP was 125 days for placebo and >365 days for the PRT-201 groups. At 1 year, 31%, 50%, and 63% of placebo, 10-µg, and 30-µg RCFs retained PP. The risk of RCF PP loss was nonsignificantly reduced by 10 µg (HR, 0.59; P = .18) and significantly reduced by 30 µg (HR, 0.37; P = .02) vs placebo. At 1 year, 77%, 81%, and 83% of placebo, 10-µg, and 30-µg patients retained SP. The risk of SP loss was nonsignificantly reduced for 10 µg (HR, 0.79; P = .61) and 30 µg (HR, 0.76; P = .55) vs placebo. In the subset with RCFs, 65%, 82%, and 90% of placebo, 10-µg, and 30-µg patients retained SP at 1 year. The risk of RCF SP loss was nonsignificantly reduced for 10 µg (HR, 0.45; P = .19) and 30 µg (HR, 0.27; P = .08) vs placebo. At month 3, 67%, 87% (P = .03), and 92% (P < .01) of the placebo, 10-µg, and 30-µg group fistulas had unassisted maturation by ultrasound interrogation. At month 3 in the subset with an RCF, 47%, 74% (P = .17), and 93% (P < .01) of placebo, 10-µg, and 30-µg group fistulas had unassisted maturation by ultrasound interrogation. Adverse event reports were not meaningfully different between groups. CONCLUSIONS: PRT-201 appeared safe. The primary efficacy end point was not met. However, both PRT-201 doses were associated with improved unassisted maturation. The 30-µg dose was associated with increased PP in the subset with RCF.

A comparison between the HeRO graft and conventional arteriovenous grafts in hemodialysis patients.

Venous stenosis and occlusion are a major cause of vascular access dysfunction and failure. The HeRO Graft bypasses occlusion and traverses stenosis with outflow directly into the central venous circulation. A randomized, multicenter study was conducted to evaluate the efficacy and safety of the HeRO Graft relative to conventional AV grafts. The design was to enroll 143 patients in a 2:1 randomization ratio between HeRO and conventional AV control groups. Data on 72 subjects (52 HeRO Graft and 20 AV graft controls) were obtained. The HeRO Graft and control cohorts were comparable in baseline characteristics. Adequacy of dialysis, bacteremia rates, and adverse events were consistent between groups. Twelve month Kaplan-Meier estimates for primary and secondary patency rates were 34.8% and 67.6% in the HeRO Graft cohort, and 30.6% and 58.4% in the control cohort. There was no statistical difference in terms of patency between groups. The rates of intervention were 2.2/year for HeRO Graft and 1.6/year for the control (p = 0.100). Median days to loss of secondary patency was 238 for HeRO Graft versus 102 for the control (p = 0.032). The HeRO Graft appears to provide similar patency, adequacy of dialysis, and bacteremia rates to those of conventional AV grafts.

Open arterial revascularization of the critically ischemic foot using arterial homograft.

BACKGROUND: Revascularization alternatives for patients with critical limb ischemia and without adequate autogenous vein remain challenging. We reviewed our experience with the use of arterial homograft as a conduit for limb salvage in patients with limb ischemia and active lower extremity infections. METHODS: A retrospective review of patients who underwent open arterial revascularization of the lower extremity with cryopreserved femoral artery homograft for the treatment of symptomatic critical limb ischemia (i.e., foot ulceration, infection, or gangrene) during an 18-month period was performed. Relevant clinical variables and treatment outcomes were analyzed. Clinical success was defined as limb salvage for one year, patency of the reconstruction, and wound healing. RESULTS: Thirteen patients (5 men; average age 71 +/- 83 years, range 51-87 years) were treated during this study period. Treatment indications included 10 (77%) foot ulcerations, 2 (15%) critically ischemic limbs without ulceration, and 1 (8%) infected polytetrafluoroethylene bypass graft with acute occlusion and limb ischemia. A femoral below-the-knee popliteal bypass was performed in 4 (1%), femoral to anterior tibial artery in 4 (31%), femoral to posterior tibial artery in 3 (23%), and femoral to peroneal artery in 2 (15%). All 13 limbs were preserved. Minor amputations were performed in 6 patients, 2 underwent toe amputations and 4 patients had a trans-metatarsal amputation. The cumulative patency rate at 6, 9, and 18 months was 92.3%, 70.3%, and 58.6%, respectively. CONCLUSION: Open arterial revascularization with arterial femoral homograft is an acceptable treatment method in patients with critical limb ischemia and active infection in whom autogenous vein is not available or the use of a synthetic conduit is not possible.