A Prospective, Randomized Study of an Expanded Polytetrafluoroethylene Stent Graft versus Balloon Angioplasty for In-Stent Restenosis in Arteriovenous Grafts and Fistulae: Two-Year Results of the RESCUE Study.

PURPOSE: To assess the safety and efficacy of an expanded polytetrafluoroethylene stent graft versus balloon angioplasty for the treatment of in-stent restenosis in the venous outflow of hemodialysis access grafts and fistulae. MATERIALS AND METHODS: Two hundred seventy-five patients were randomized at 23 US sites to stent-graft placement or percutaneous transluminal angioplasty (PTA). Primary study endpoints were access circuit primary patency (ACPP) at 6 months and safety through 30 days; secondary endpoints were evaluated through 24 months. RESULTS: ACPP at 6 months was significantly higher in the stent-graft group (18.6%) versus the PTA group (4.5%; P < .001), and freedom from safety events (30 days) was comparable (stent graft, 96.9%; PTA, 96.4%; P = .003 for noninferiority). The separation in ACPP survival curves remained through 12 months (stent graft, 6.2%; PTA, 1.5%). Treatment area primary patency (TAPP) was superior for the stent-graft group (66.4%) versus the PTA group (12.3%) at 6 months (P < .001), with a survivorship difference in favor of stent-graft placement maintained through 24 months (stent graft, 15.6%; PTA, 2.2%). ACPP and TAPP for the stent-graft group were better than those for the PTA group when compared within central and peripheral vein subgroups (P < .001). In central veins, TAPP was 13.6% in the stent-graft group versus 4.3% in the PTA group at 24 months (P < .001). CONCLUSIONS: Stent-graft use provided better ACPP and TAPP than PTA when treating in-stent restenosis in patients receiving dialysis with arteriovenous grafts and fistulae.

Transcatheter anastomosis connector system for vascular access graft placement: results from a first-in-human pilot study.

PURPOSE: A lengthy healing and maturation period follows standard surgical preparation of a permanent arteriovenous access, often requiring or extending use of a venous catheter (VC) for hemodialysis. The InterGraft™ Anastomotic Connector System was developed for minimally invasive anastomosis of an arteriovenous graft (AVG). The venous and arterial InterGraft™ connectors are designed to provide optimized flow dynamics and may result in reduction of AVG stenosis. This pilot study evaluated placement procedure success, patency and safety of the InterGraft™ connectors. METHODS: Nine AVGs were implanted in nine patients currently receiving dialysis with a VC. The study allowed use of both connectors (n = 5) or use of the venous connector with a sutured arterial anastomosis (n = 4). Monthly ultrasound examinations were performed throughout the six-month follow-up. AVG angiography was performed at five months. Endpoints included procedure success (acceptable graft flow at end of procedure, without significant bleeding or need for emergent surgery), patency, and device-related major adverse events. RESULTS: Procedure success was attained in all patients. AVGs were used for dialysis within 17 days, on average, and VCs were removed. Three patients exited the study early for reasons unrelated to the InterGraft™ connectors. The remaining six patients had patent grafts: two with assisted and four with unassisted patency. AVG flow rates were greater than 1 L/minute. No dilatations or aneurysms were observed by angiography. There were no device-related major adverse events. CONCLUSIONS: The InterGraft™ connectors can be safely and successfully used for AVG anastomoses, with acceptable near-term patency. Further clinical evaluation is warranted.

Hand Ischemia in a Patient With an Arteriovenous Fistula.

An ischemic digit causes significant morbidity due to its associated discomfort and potential for tissue necrosis. Historically, when this phenomenon was peripheral to an ipsilateral arteriovenous access in a hemodialysis patient, it was called "steal syndrome" and was usually treated with access ligation, resulting in loss of the access. We present a dialysis patient with hand pain due to ischemia that was referred for access ligation. Instead, a minimally invasive banding procedure was performed that resulted in access salvage and resolution of symptoms. We present images and a discussion of the diagnosis and treatment of distal hypoperfusion ischemia syndrome in this Imaging Teaching Case.

Percutaneous versus surgical insertion of PD catheters in dialysis patients: a meta-analysis.

PURPOSE: Several small studies have suggested that the percutaneous method of peritoneal dialysis (PD) catheter insertion is effective and has a lower complication rate than surgical techniques (open, laparoscopic or peritoneoscopic), although no randomized, controlled study has compared these methods. Our objective was to compare percutaneous PD catheter insertion vs surgical placement in terms of 1-year catheter survival, catheter dysfunction, fluid leak and incidence of peritonitis. METHODS: We searched Medline for English-language literature from 1966 through June 2014, along with national conference proceedings and reference lists of all included publications to identify relevant studies. Inclusion criteria were having a measure of catheter survival at 1 year, catheter dysfunction, peritonitis rate per patient-month or fluid leak as outcomes. Studies were excluded if they were not in English or if they included pediatric patients. Random effects models were used to derive the pooled risk ratios, differences in patency and their variations. RESULTS: Thirteen studies with a total of 2,681 subjects met the inclusion criteria. There was no significant difference in 1-year catheter survival in percutaneous vs surgical PD catheter placement (relative risk [RR] = 0.81; 95% confidence interval [CI]: 0.59-1.11, p = 0.19). Catheter dysfunction also did not differ significantly between the groups (pooled odds ratio [OR] = 0.86; 95% CI: 0.57-1.29, p = 0.46). The prevalence of peritoneal fluid leak also was similar for percutaneous and surgical groups (OR = 1.10; 95% CI: 0.58-2.09, p = 0.77). However, there was a significant lower incidence of peritonitis among those with percutaneous placement (incidence rate ratio [IRR] = 0.77; 95% CI: 0.62-0.96, p = 0.02). Significant heterogeneity was detected across studies (I2 = 78.4%, p<0.0001). CONCLUSIONS: Our results suggest that there is no significant difference in catheter survival between percutaneous and surgical placement of PD catheters. Whether there are significant benefits from percutaneous placement in terms of peritonitis rates requires further robust studies. These findings have significant implications for future design of clinical trials in the placement of PD catheters and the delivery of dialysis-related services.

Interventional nephrology: Novel devices that will one day change our practice.

There is increasing awareness of vascular access dysfunction as a significant contributor to the morbidity associated with chronic hemodialysis. Over the last several years, interventional nephrologists, in conjunction with our colleagues in vascular surgery, have led the way in the creation of novel devices that are designed to help solve the vascular access problem. The purpose of this review is to describe novel devices in the precommercial stage of development that have the potential to revolutionize the field of dialysis vascular access. These devices include bioengineered blood vessels, access monitoring technology, and advanced anastomotic connectors.

Cell-based approaches for the treatment of systemic inflammation.

Acute and chronic solid organ failures are costly disease processes with high mortality rates. Inflammation plays a central role in both acute and chronic organ failure, including heart, lung and kidney. In this regard, new therapies for these disorders have focused on inhibiting the mediators of inflammation, including cytokines and free radicals, with little or no success in clinical studies. Recent novel treatment strategies have been directed to cell-based rather than mediator-based approaches, designed to immunomodulate the deleterious effects of inflammation on organ function. One approach, cell therapy, replaces cells that were damaged in the acute or chronic disease process with stem/progenitor technology, to rebalance excessive inflammatory states. As an example of this approach, the use of an immunomodulatory role of renal epithelial progenitor cells to treat acute renal failure (ARF) and multiorgan failure arising from acute kidney injury is reviewed. A second therapeutic pathway, cell processing, does not incorporate stem/progenitor cells in the device, but rather biomimetic materials that remove and modulate the primary cellular components, which promote the worsening organ tissue injury associated with inflammation. The use of an immunomodulating leukocyte selective cytopheretic inhibitory device is also reviewed as an example of this cell processing approach. Both of these unconventional strategies have shown early clinical efficacy in pilot clinical trials and may transform the therapeutic approach to organ failure disorders.

Calciphylaxis responsive to lanthanum carbonate (FOSRENOL) therapy.

Calciphylaxis is a rare and debilitating vasculopathy predominantly seen in patients with renal failure. The proposed mechanism of injury is active vascular calcification with associated elevated parathyroid hormone, hypercalcemia, or hyperphosphatemia. With improved pharmacologic agents including non-calcium containing phosphate binders, vitamin D analogues, calcimimetics, and bisphosphonates, targeted therapy on the mineralization process has been tried with varied success. We report a case of biopsy-proven calciphylaxis in a patient with acute kidney injury requiring dialysis that had persistently elevated calcium-phosphorus product refractory to treatment. The patient, however, responded rapidly to the initiation of lanthanum carbonate therapy and modified dialysis. This is the first known case reported in the literature utilizing this new non-calcium-based phosphate binder in the setting of calciphylaxis.