Hemodialysis Reliable Outflow (HeRO) graft creation in upper extremities abandoned due to stent obstruction via recanalization and HeRO outflow component insertion across stent interstices.

BACKGROUND: The purpose of this study was to assess the feasibility and outcomes of recanalization and subsequent HeRO graft outflow component insertion across stent interstices in patients with an otherwise abandoned upper extremity. METHODS: Over a 10-year period, 15 patients underwent central venous recanalization by interventional radiology across the interstices of one or more occluded stents for the purpose of subsequent HeRO graft creation. A tunneled central venous catheter was left across the stent and occlusions with tip in right atrium. On a later date, the catheter was used for rapid guidewire access for HeRO graft implantation in the OR by vascular surgery. Procedural and clinical outcomes were determined by retrospective review. Primary and secondary HeRO graft patency rates were estimated with the Kaplan-Meier technique. RESULTS: The technical success rates of recanalization across stent interstices was 100% (15/15). Between one and four overlapping stent walls were traversed. The technical success of the patients who underwent attempted HeRO graft implantation with outflow component traversing across stent interstices was 91% (11/12). No major complications were encountered with either recanalization or HeRO graft implantation. The primary and secondary HeRO patency rates at 12 months were 64% and 80%, respectively. CONCLUSION: HeRO graft insertion across stent interstices is feasible and can provide effective permanent AV access; thus, the presence of stents across the subclavian and brachiocephalic veins should not be considered a contraindication.

Use of a novel immediate access dialysis graft designed to prevent needle-related complications: A first-in-man case report.

Currently, there is no vascular access that possesses all ideal qualities for hemodialysis access, but attributes particularly lacking include: ease of identification (cannulation zone), ease of access, resistance to stenosis, durable to repetitive cannulation, resistance to infection, resistance to acute needle-related injuries, and instant hemostasis. The overall value of these attributes could be appreciated in the reduction of complications (patient burden and suffering, which can also result in increased healthcare costs), and improved safety and durability. In this case report, we present a novel hemodialysis access graft that has the potential to provide the following benefits: it is designed to be self-sealing and immediately usable post implant, easy to identify, easy to access, has more durable cannulation zones, and protects from needle-related injuries. This case report describes the first-in-man use of this novel graft technology to replace a giant, thrombotic, and difficult-to-access arteriovenous fistula to provide the patient with a potentially safer and more durable access that does not require placement of a bridging dialysis catheter. This single-patient experience suggests that implantation and function of this novel graft as a hemodialysis access is feasible in a human subject with end-stage renal disease, and it suggests that the novel properties (i.e. immediate use, easy identification, easy use, cannulation zone durability, and protection from needle-related injuries) of this graft seem to function as intended.

Determining the incidence of needle-related complications in hemodialysis access: We need a better system.

INTRODUCTION: Hemodialysis access complications are common. We hypothesize that many of these complications can be traced back to needle-related injury from routine cannulation practices or inadvertent cannulation injuries. We set out to compare the rates of hemodialysis access complications under prior and current diagnosis coding systems, determine the incidence of needle-related complications for hemodialysis access, and describe the association of needle-related complications and resulting interventions. METHODS: Arteriovenous graft and arteriovenous fistula placements occurring in the first 6 months of 2014 and 2016 were identified in the United States Renal Data System Medicare claims data. Placements were followed until end of hemodialysis access life or end of the calendar year. Diagnoses and resulting interventions occurring during placement life were identified and mapped to needle-related complication terms. RESULTS: Almost 30,000 placements for 27,000 patients were followed in each year, with 67% of all accesses placed being arteriovenous fistula and 33% arteriovenous graft. In both years, 75% of arteriovenous fistulae and arteriovenous grafts required one or more interventions. Stenosis and thrombosis were the most common complications diagnosed and treated (41% and 16%, respectively); however, potential needle-related complications accounted for 6% of this dataset. DISCUSSION: International Classification of Diseases, 9th Revision, was inadequate for determining the incidence of specific hemodialysis access complications or needle-related complications. International Classification of Diseases, 10th Revision, introduced several more hemodialysis access diagnoses but is still subject to coding confusion and catch-all coding for a variety of common and otherwise well-defined complications, suggesting that the true incidence of needle-related complications is buried in the non-specific diagnosis codes. These findings mark the clear need for an improved diagnosis coding system that consistently represents all common hemodialysis access complications.

Arterial reconstruction with human bioengineered acellular blood vessels in patients with peripheral arterial disease.

OBJECTIVE: Vascular conduit is essential for arterial reconstruction for a number of conditions, including trauma and atherosclerotic occlusive disease. We have developed a tissue-engineered human acellular vessel (HAV) that can be manufactured, stored on site at hospitals, and be immediately available for arterial vascular reconstruction. Although the HAV is acellular when implanted, extensive preclinical and clinical testing has demonstrated that the HAV subsequently repopulates with the recipient's own vascular cells. We report a first-in-man clinical experience using the HAV for arterial reconstruction in patients with symptomatic peripheral arterial disease. METHODS: HAVs were manufactured using human vascular smooth muscle cells grown on a biodegradable scaffold. After the establishment of adequate cell growth and extracellular matrix deposition, the vessels were decellularized to remove human cellular antigens. Manufactured vessels were implanted in 20 patients with symptomatic peripheral arterial disease as above-knee, femoral-to-popliteal arterial bypass conduits. After HAV implantation, all patients were assessed for safety, HAV durability, freedom from conduit infection, and bypass patency for 2 years. RESULTS: Twenty HAVs were placed in the arterial, above-knee, femoral-to-popliteal position in patients with rest pain (n = 3) or symptomatic claudication (n = 17). All HAVs functioned as intended and had no evidence of structural failure or rejection by the recipient. No acute HAV infections were reported, but three surgical site infections were documented during the study period. Three non-HAV-related deaths were reported. One vessel developed a pseudoaneurysm after suspected iatrogenic injury during a balloon thrombectomy. No amputations of the HAV implanted limb occurred over the 2-year period, and no HAV infections were reported in approximately 34 patient-years of continuous patient follow-up. CONCLUSIONS: Human tissue engineered blood vessels can be manufactured and readily available for peripheral arterial bypass surgery. Early clinical experience with these vessels, in the arterial position, suggest that they are safe, have acceptable patency, a low incidence of infection, and do not require the harvest of autologous vein or any cells from the recipient. Histologic examination of tissue biopsies revealed vascular remodeling and repopulation by host cells. This first-in-man arterial bypass study supports the continued development of human tissue engineered blood vessels for arterial reconstruction, and potential future expansion to clinical indications including vascular trauma and repair of other size-appropriate peripheral arteries.

Vascular access-specific health-related quality of life impacts among hemodialysis patients: qualitative development of the hemodialysis access-related quality of life (HARQ) instrument.

BACKGROUND: End stage kidney disease and hemodialysis dependence are associated with impairments in health-related quality of life (HRQOL), which may be related to vascular access (VA). Few HRQOL measures are VA-specific and none differentiate HRQOL impact by VA type. We developed a VA-targeted HRQOL measure to distinguish the impact of fistulas, grafts and catheters. METHODS: We created an initial item pool based on literature review and then conducted focus groups at 4 US sites with 37 adults and interviews with nine dialysis clinicians about VA's impact on HRQOL. We then drafted the Hemodialysis Access-Related Quality of Life (HARQ) measure and cognitively tested it with 17 hemodialysis patients. Focus group and cognitive interview participants were diverse in age, gender, years on dialysis, and VA. RESULTS: We identified six domains for the HARQ: symptoms, physical functioning, emotional impacts, social and role functioning, sleep, and care-related burdens. Cognitive interviews indicated that items were easily understood and supported content validity. Attributing HRQOL impact to VA as opposed to other hemodialysis burden was challenging for some items. Some items were dropped that were considered redundant by patients, limitations while dressing was added, and reference to VA-specific impact was included for each item. The average Flesch-Kincaid reading grade level for the revised 47-item HARQ was 5.3. CONCLUSIONS: The HARQ features VA-specific content not addressed in other HRQOL measures, making it ideal for comparisons of different VA types and new VA technologies. The psychometric properties of the HARQ will be evaluated in future research.

An immediate access dialysis graft designed to prevent needle-related complications: Results from the initial pre-clinical studies.

INTRODUCTION: No technology has been specifically developed with the intent to reduce needle-related vascular access injuries; a significant source of complications and abandonment. We present the initial pre-clinical study results of a novel, self-sealing, immediate cannulation dialysis graft that aims to prevent needle-related complications; to promote safe, reliable needle access; to reduce catheter use; and could facilitate home hemodialyisis. METHODS: The innovative graft design consists of two cannulation chambers with self-sealing properties and materials that prevent side and back wall needle puncture. Study and control grafts (expanded polytetrafluoroethylene) were implanted in one pig and 10 sheep in two studies over the course of 1 year. First cannulation occurred immediately post implant for all study grafts. Post-cannulation time to hemostasis, hematoma and seroma formation, infection, and patency were recorded. RESULTS: The two studies account for nearly 60 weeks (average 6.4 weeks/graft) of study graft follow-up. In the ovine study, average study graft time to hemostasis was 27.3 s (standard deviation = 26.3, range = 0-120), and the control averaged 177.2 s (standard deviation = 113.4, range = 60-600), p < 0.0001. Secondary patency was 75% and 67% for the study and control grafts, respectively. Neither study nor control groups experienced seroma, graft infections, or deaths. DISCUSSION: All novel grafts in the studies were implanted successfully and functioned as intended. There were no complications related to tunneling of the study graft and the chamber prevented back/side wall needle injury. This novel technology may help to mitigate these needle-related complications, while allowing for early/immediate cannulation which could also reduce catheter contact time.

Treatment of Arm Swelling in Hemodialysis Patients with Ipsilateral Arteriovenous Access and Central Vein Stenosis: Conversion to the Hemodialysis Reliable Outflow Graft versus Stent Deployment.

PURPOSE: To compare outcomes after conversion of arteriovenous (AV) access to Hemodialysis Reliable Outflow (HeRO) graft vs stent deployment in patients with arm swelling owing to ipsilateral central vein stenosis. MATERIALS AND METHODS: This single-center retrospective study comprised 48 patients (19 men, mean age 58 y) with arm swelling ipsilateral to AV access and central vein stenosis over a 13-year period who had clinical follow-up and without prior central stents. Twenty-one patients underwent placement of a HeRO graft with anastomosis of the HeRO graft to the existing graft or fistula, and 27 patients underwent central venous stent deployment. Symptomatic improvement in arm swelling and access patency rates after intervention were ascertained from medical records. RESULTS: Improvement in swelling within 1 month after HeRO conversion and stent deployment was found in 95% and 89%, respectively (P = .62). Swelling eventually recurred in 16 patients (59%) treated with stents compared with 1 patient (5%) who underwent HeRO conversion (P < .001). Primary access patency was statistically significantly longer after HeRO conversions than stent deployments, with 6- and 12-month primary patency rates of 89% and 72% vs 47% and 11% (P < .001). HeRO conversions also resulted in longer 6- and 12-month secondary access patency rates (95% and 95% vs 79% and 58%, P = .006). Mean number of interventions per 1,000 access days to maintain secondary patency was 2.7 for the HeRO group vs 6.3 for the stent group. CONCLUSIONS: Although stent deployment and HeRO graft conversion are effective for alleviating arm swelling in the short term in patients receiving hemodialysis with clinically significant arm swelling and functioning AV access, the HeRO graft has more durable results.

Costs Attributable to Arteriovenous Fistula and Arteriovenous Graft Placements in Hemodialysis Patients with Medicare coverage.

INTRODUCTION: Hemodialysis (HD) in end-stage renal disease (ESRD) patients requires vascular access (VA) through an arteriovenous fistula (AVF), a prosthetic arteriovenous graft (AVG), or a central venous catheter. While AVF or AVG is commonly used for HD, the economic implications of AVF versus AVG use have not been fully established. We describe the healthcare resource utilization and costs of AVF and AVG use for incident ESRD patients in the United States. METHODS: This observational cohort study of AVF and AVG placements used data from the United States Renal Data System to identify and follow access placements. AVF and AVG placements after ESRD onset for incident patients from 2012 to 2014 with continuous Medicare primary coverage were included. All-cause and access-related Medicare costs were averaged over the placement lifetime and expressed as per dialysis-month costs. RESULTS: The analysis included 38,035 AVF placements and 12,789 AVG placements. Total all-cause monthly costs for AVF averaged USD 8,508; mean monthly costs were USD 3,027 for inpatient (IP), USD 3,139 for outpatient (OP), USD 1,572 for physician services, and USD 770 for other care settings. Access-related monthly costs averaged USD 1,699 and represented 20% of all-cause charges for AVFs. Mean all-cause monthly costs for AVG were USD 9,605; by setting monthly costs were USD 3,811 for IP, USD 3,034 for OP, USD 1,881 for physician services and USD 879 for other care settings. Access-related monthly costs averaged USD 2,656 and represented 28% of all-cause charges for AVGs. DISCUSSION/CONCLUSIONS: This study indicates that costs due to VA are a significant burden on Medicare budgets and on patients. The factors driving access-related utilization and costs merit attention in future research. Both optimizing process of care and discovery innovation may significantly accelerate better stewardship of available healthcare resources.

Clinical Outcomes of Arteriovenous Access in Incident Hemodialysis Patients with Medicare Coverage, 2012-2014.

BACKGROUND: Chronic hemodialysis requires a mode of vascular access through an arteriovenous fistula (AVF), a prosthetic arteriovenous graft (AVG), or a central venous catheter (CVC). AVF is recommended over AVG or CVC due to increased patency and decreased intervention rates for those that mature. AVG are preferred over CVC due to decreased infection and mortality risk. The aims of this study were to evaluate the lifespan of AVF and AVG in maturation, sustained access use, and abandonment. METHODS: The United States Renal Data System (USRDS), Medicare claims, and CROWNWeb were used to identify access placements. Patients with a first end-stage renal disease (ESRD) service from January 1, 2012 to June 30, 2014 with continuous coverage with Medicare as primary payer and ≥1 AVF or AVG placed after ESRD onset were included. Maturation was defined as the first use of the access for hemodialysis recorded in CROWNWeb. Sustained access use was defined as 3 consecutive months of use without catheter placement or replacement. Accesses that were never used at any time post-placement were considered abandoned. RESULTS: The cohort included 38,035 AVF placements and 12,789 AVG placements. Sixty-nine percent of AVF and 72% of AVG matured. Fifty-two percent of AVF and 51% of AVG achieved sustained access use. One quarter of AVF and 14% of AVG were abandoned without use as recorded in CROWNWeb. CONCLUSION: Although considered the gold standard for vascular access, only half of AVF and AVG placements achieved sustained access use. The USRDS database has inherent limitations but provides useful clinical insight into maturation, sustained use, and abandonment.

Bioengineered hemodialysis access grafts.

There is a need for bioengineered therapies to improve the overall health of the growing and aging world population. Patients with renal failure have a life-long requirement for a durable form of hemodialysis vascular access. In this article, we review the history of tissue engineering as it pertains to bioengineered grafts and vessels for hemodialysis access. Over the years, various strategies have been utilized to develop ideal, humanized vessels for vascular replacement such as fixation of animal or human vessels, cell seeding of synthetic materials, and the synthesis of completely autologous or allogeneic bioengineered vessels. Tissue engineering technologies from two companies have progressed to reach phase 2 and phase 3 clinical trials, but the prospect of newer strategies on the horizon may offer improved manufacturing efficiency, a greater variety of conduit size and length, and reduce the cost to produce.

Forearm versus upper arm grafts for vascular access.

Forearm and upper arm arteriovenous grafts perform similarly in terms of patency and complications. Primary patency at 1 year for forearm arteriovenous grafts versus upper arm grafts ranges from 22%-50% versus 22%-42%, and secondary patency at 1 year ranges from 78%-89% versus 52%-67%), respectively. Secondary patency at 2 years, ranges from 30%-64% versus 35%-60% for forearm and upper arteriovenous graft, respectively. Ample pre-operative planning is essential to improved clinical success and the decision to place a graft at one location versus the other should be based solely on previous access history, physical exam, appropriate venous imaging, and other factors that make up the clinical picture. Operative implant strategies and risk of complications are very similar between the two configurations. Postoperative ischemia due to steal syndrome is a potential complication that requires immediate attention. Utilization of the proximal radial or ulnar artery for inflow for the graft can minimize risk of clinically relevant steal syndrome.

Early infection risk with primary versus staged Hemodialysis Reliable Outflow (HeRO) graft implantation.

OBJECTIVE: This study evaluated whether the use of a staged Hemodialysis Reliable Outflow (HeRO; Merit Medical, South Jordan, Utah) implantation strategy incurs increased early infection risk compared with conventional primary HeRO implantation. METHODS: A retrospective review was performed of 192 hemodialysis patients who underwent HeRO graft implantation: 105 patients underwent primary HeRO implantation in the operating room, and 87 underwent a staged implantation where a previously inserted tunneled central venous catheter was used for guidewire access for the venous outflow component. Within the staged implantation group, 32 were performed via an existing tunneled hemodialysis catheter (incidentally staged), and 55 were performed via a tunneled catheter inserted across a central venous occlusion in an interventional radiology suite specifically for HeRO implantation (intentionally staged). Early infection was defined as episodes of bacteremia or HeRO infection requiring resection ≤30 days of HeRO implantation. RESULTS: For staged HeRO implantations, the median interval between tunneled catheter insertion and conversion to a HeRO graft was 42 days. The overall HeRO-related infection rate ≤30 days of implantation was 8.6% for primary HeRO implantation and 2.3% for staged implantations (P = .12). The rates of early bacteremia and HeRO resection requiring surgical resection were not significantly different between groups (P = .19 and P = .065, respectively), nor were age, gender, laterality, anastomosis to an existing arteriovenous access, human immunodeficiency virus status, diabetes, steroids, chemotherapy, body mass index, or graft location. None of the patient variables, techniques, or graft-related variables correlated significantly with the early infection rate. CONCLUSIONS: The staged HeRO implantation strategy did not result in an increased early infection risk compared with conventional primary implantation and is thus a reasonable strategy for HeRO insertion in hemodialysis patients with complex central venous disease.

Hemodialysis Reliable Outflow device impingement in the subclavian position: a case report.

PURPOSE: The purpose of this study is to report a case of Hemodialysis Reliable Outflow (HeRO) device malfunction in the subclavian position secondary to costoclavicular impingement. METHODS AND RESULTS: The electronic medical record was reviewed for the patient in question and pertinent imaging was collected and photographs were taken with the patient's consent. The patient presented with signs of outflow obstruction after a period of HeRO venous outflow component function. The outflow component was found to be crushed between the first rib and the clavicle at the costoclavicular junction. CONCLUSIONS: This case suggests that costoclavicular impingement should be considered as a mode of outflow failure with the HeRO outflow component in the subclavian position. Other central venous access points should be considered first, and the central veins accessed through the lower extremities are possible alternatives if this failure mode was to arise. First rib resection would also be a viable strategy to relieve impingement at this site.

Percutaneous interventions on the hemodialysis reliable outflow vascular access device.

PURPOSE: To determine the outcomes of percutaneous interventions for prolonging the patency of the Hemodialysis Reliable Outflow (HeRO) device. MATERIALS AND METHODS: Between January 2007 and August 2011, 73 percutaneous interventions were performed on 26 HeRO devices in 25 patients. The graft was implanted in the upper arm with the outflow catheter tip in the superior vena cava or right atrium. Procedural reports, angiographic images, and clinical notes were retrospectively reviewed. The primary and secondary patency rates after intervention were calculated using the Kaplan-Meier method. RESULTS: The mean time from HeRO implantation to initial dysfunction or thrombosis was 171 days. In 60 (82%) procedures, the HeRO device was thrombosed. An intragraft stenosis was the most common lesion identified (59%; n = 43) followed by an arterial anastomosis stenosis identified in 18% (n = 13). In 22% (n = 16) of procedures in which the HeRO device was thrombosed, an underlying cause was not identified after thrombectomy. The 3-, 6-, and 12-month primary patency rates after intervention were 47%, 37%, and 26% for first-time interventions. The secondary patency rates were 80%, 70%, and 64%. The only complication was pulmonary embolism resulting in death 2 days after HeRO thrombectomy. CONCLUSIONS: Percutaneous interventions on thrombosed and failing HeRO devices yielded acceptable primary and secondary patency rates after intervention in these patients with few, if any, alternatives for hemodialysis access.

Tissue-engineered vascular grafts: autologous off-the-shelf vascular access?

Dialysis grafts have provided reliable access for millions of patients in need of renal replacement therapy. However, regardless of the material used for artificial dialysis grafts their mean patency remains generally poor and infection rates are greater than native arteriovenous fistulas. The need for superior alternatives to conventional synthetic materials used for vascular access has been an area of investigation for more than 25 years and recently there has been a great deal of progress in the field of tissue-engineered vascular grafts. Many of these technologies are either commercially available or are now entering early phases of clinical trials. This review briefly covers the history, potential advantages, and disadvantages of these technologies, which are likely to create an impact in the field of vascular access surgery.

Analysis of infection risk following covered stent exclusion of pseudoaneurysms in prosthetic arteriovenous hemodialysis access grafts.

PURPOSE: To determine whether exclusion of pseudoaneurysms with the use of a covered stent in prosthetic arteriovenous (AV) hemodialysis access grafts impacts the incidence of eventual AV graft infection. MATERIALS AND METHODS: Review of an interventional radiology database for prosthetic AV graft interventions involving stent deployment anywhere within the AV graft circuit revealed 235 interventions in 174 patients between November 2004 and December 2008. Incidence of AV graft infection was analyzed based on stent type (bare metal vs covered), location, and indication for stent deployment on a per-stent, per-procedure, and per-graft basis. RESULTS: A total of 16.3% of the stent-implanted AV grafts were eventually surgically excised as a result of graft infection. Covered stents used to treat an intragraft pseudoaneurysm were more commonly associated with subsequent graft infection compared with bare or covered stents deployed within the graft for other reasons: 42.1% versus 18.2% (P = .011). Stents deployed in an intragraft location were also associated with a higher incidence of graft infection compared with those deployed at the venous anastomosis or outflow vein: 26.9% versus 6.9% (P < .001). No significant difference was identified in infection rates between bare and covered stents. CONCLUSIONS: Covered stent exclusion of intragraft pseudoaneurysms demonstrated a significant correlation with eventual prosthetic AV graft infection.

Autologous endothelial progenitor cell-seeding technology and biocompatibility testing for cardiovascular devices in large animal model.

Implantable cardiovascular devices are manufactured from artificial materials (e.g. titanium (Ti), expanded polytetrafluoroethylene), which pose the risk of thromboemboli formation. We have developed a method to line the inside surface of Ti tubes with autologous blood-derived human or porcine endothelial progenitor cells (EPCs). By implanting Ti tubes containing a confluent layer of porcine EPCs in the inferior vena cava (IVC) of pigs, we tested the improved biocompatibility of the cell-seeded surface in the prothrombotic environment of a large animal model and compared it to unmodified bare metal surfaces (Figure 1). This method can be used to endothelialize devices within minutes of implantation and test their antithrombotic function in vivo. Peripheral blood was obtained from 50 kg Yorkshire swine and its mononuclear cell fraction cultured to isolate EPCs. Ti tubes (9.4 mm ID) were pre-cut into three 4.5 cm longitudinal sections and reassembled with heat-shrink tubing. A seeding device was built, which allows for slow rotation of the Ti tubes. We performed a laparotomy on the pigs and externalized the intestine and urinary bladder. Sharp and blunt dissection was used to skeletonize the IVC from its bifurcation distal to the right renal artery proximal. The Ti tubes were then filled with fluorescently-labeled autologous EPC suspension and rotated at 10 RPH x 30 min to achieve uniform cell-coating. After administration of 100 USP/kg heparin, both ends of the IVC and a lumbar vein were clamped. A 4 cm veinotomy was performed and the device inserted and filled with phosphate-buffered saline. As the veinotomy was closed with a 4-0 Prolene running suture, one clamp was removed to de-air the IVC. At the end of the procedure, the fascia was approximated with 0-PDS (polydioxanone suture), the subcutaneous space closed with 2-0 Vicryl and the skin stapled closed. After 3 - 21 days, pigs were euthanized, the device explanted en-block and fixed. The Ti tubes were disassembled and the inner surfaces imaged with a fluorescent microscope. We found that the bare metal Ti tubes fully occluded whereas the EPC-seeded tubes remained patent. Further, we were able to demonstrate a confluent layer of EPCs on the inside blood-contacting surface. Concluding, our technology can be used to endothelialize Ti tubes within minutes of implantation with autologous EPCs to prevent thrombosis of the device. Our surgical method allows for testing the improved biocompatibility of such modified devices with minimal blood loss and EPC-seeded surface disruption.

Use of autologous blood-derived endothelial progenitor cells at point-of-care to protect against implant thrombosis in a large animal model.

Titanium (Ti) is commonly utilized in many cardiovascular devices, e.g. as a component of Nitinol stents, intra- and extracorporeal mechanical circulatory assist devices, but is associated with the risk of thromboemboli formation. We propose to solve this problem by lining the Ti blood-contacting surfaces with autologous peripheral blood-derived late outgrowth endothelial progenitor cells (EPCs) after having previously demonstrated that these EPCs adhere to and grow on Ti under physiological shear stresses and functionally adapt to their environment under flow conditions ex vivo. Autologous fluorescently-labeled porcine EPCs were seeded at the point-of-care in the operating room onto Ti tubes for 30 min and implanted into the pro-thrombotic environment of the inferior vena cava of swine (n = 8). After 3 days, Ti tubes were explanted, disassembled, and the blood-contacting surface was imaged. A blinded analysis found all 4 cell-seeded implants to be free of clot, whereas 4 controls without EPCs were either entirely occluded or partially thrombosed. Pre-labeled EPCs had spread and were present on all 4 cell-seeded implants while no endothelial cells were observed on control implants. These results suggest that late outgrowth autologous EPCs represent a promising source of lining Ti implants to reduce thrombosis in vivo.

Salvaging vascular access and treatment of severe limb edema: case reports on the novel use of the hemodialysis reliable outflow vascular access device.

We report two cases in which patients on chronic hemodialysis presented with morbid unilateral edema of the upper extremity and chest on the side of a currently functioning arteriovenous access. Both patients were known to the vascular surgery service and had previously undergone multiple attempts to create and maintain vascular access. Both severe and disabling edema and the need to maintain dialysis access were of significant concern. These patients were taken to the operating room to address both issues. Upper extremity venography with central venous runoff revealed central vein stenosis and/or occlusion resistant to angioplasty and stenting. Ultimately, these two patients received the Hemodialysis Reliable Outflow vascular access device. The experiences in this study demonstrate the novel use of a relatively new vascular access device for salvage of a malfunctioning arteriovenous fistula or graft as well as treatment of symptoms and complications resulting from long standing vascular access.