Ilya Goldin

Angioplasty with stent graft versus bare stent for recurrent cephalic arch stenosis in autogenous arteriovenous access for hemodialysis: A prospective randomized clinical trial

BACKGROUND Early recurrent stenosis of the cephalic arch in autogenous arteriovenous access for hemodialysis is a common problem that requires stenting to prevent thrombosis. Because the results of stenting are unsatisfactory, we compared the efficacy of stent grafts with bare stents in these patients. METHODS All patients who presented with recurrent cephalic arch stenosis >50% within 3 months of successful balloon angioplasty were randomized to have angioplasty and stenting with either a bare nitinol stent or a stent graft. Outcome was assessed by angiography 3 months later. Restenosis was defined as >50% narrowing of the stent lumen or of the vessel margin up to 0.5 cm adjacent to the stent. There were no exclusions. RESULTS This report includes data on the outcome of 25 consecutive patients with recurrent cephalic arch stenosis who were treated from April to August 2006. At 3 months, three patients had died and one had undergone a renal transplant. The 21 patients who had angiography at 3 months had patent stents. Restenosis rates were seven of 10 (70%) in the bare stent group and two of 11 (18%) in the stent graft group (P = .024). Life-table analysis at 3 and 6 months showed that primary patency was 82% in the stent graft group and 39% in the bare stent group. One-year primary patency was 32% in the stent graft group and 0% in the bare stent group (P = .0023). During a mean follow-up of 13.7 months, nine patients died, four in the bare stent group and five in the stent graft group. Two patients in the stent graft group had received a renal transplant. The number of interventions per patient-year was 1.9 in the bare stent group and 0.9 in the stent graft group (P = .02). CONCLUSIONS The use of stent grafts in angioplasty for recurrent cephalic arch stenosis significantly improved short-term restenosis rates and long-term patency compared with the use of bare stents. The significant improvement that emerged during the study caused accrual of patients to be halted for ethical reasons. This study altered our usage of stents for venous stenoses in arteriovenous accesses by eliminating bare nitinol stents in favor of stent grafts.

Stent graft treatment for hemodialysis access aneurysms

BACKGROUND Aneurysms that develop in arteriovenous accesses as a result of repeated punctures are sometimes complicated by infection or ischemia causing sloughing of the overlying skin, which may endanger the access and risk major bleeding and other complications. Surgical revision may necessitate the temporary use of a central venous catheter until dialysis can be resumed via the access. We used stent grafts in selected patients for the exclusion of access aneurysms. METHODS Twenty of 63 patients requiring access revision for complication of an aneurysm from February 2005 to December 2009 underwent ambulatory endovascular stent graft deployment. Indications included signs of impending rupture, questionable viability of overlying skin, pain, infection, and limitation of cannulation sites by the size or number of the aneurysms. Endovascular treatment always included angioplasty of associated outflow or central vein stenoses at the same ambulatory session. RESULTS Twenty patients with complicated access aneurysms were treated by endovascular stent graft exclusion at an average of 4.8 ± 4.3 years (range, 0.2 to 16.1 years) after access construction: nine graft pseudoaneurysms, nine native vein aneurysms, and two acute iatrogenic pseudoaneurysms. Six patients had skin erosion over the aneurysm, and 12 had painful aneurysms and clinical signs of compromised blood supply to the skin. Another two patients with an acute giant false aneurysm occurring during endovascular procedures were treated in the same interventional session by the stenting technique to control bleeding. All the aneurysms underwent endovascular exclusion without complications. Only one infected puncture site failed to heal within 2 months of stenting and was closed surgically 10 months later due to persistent localized graft infection, but with no further bleeding episodes. Only one aneurysm did not reabsorb within 3 months. Patients with painful skin ischemia had immediate pain relief. All patients also had stenosis in the draining veins necessitating additional percutaneous transluminal angioplasty. Only one patient required hospitalization (for intravenous antibiotic treatment of staphylococcal sepsis). No patients required a central catheter for hemodialysis. One access occluded due to cephalic arch stenosis in a noncompliant patient. Functional patency was 87% at 12 months, with a median follow-up of 15 months (range, 6.3 to 55.5 months). CONCLUSION Endovascular treatment with stent grafts in complicated access aneurysms is a simple, safe and rapid ambulatory procedure that enables treatment of both the aneurysm and its accompanying draining vein stenosis. It enables continued cannulation of the existing access and avoids the use of central catheters.

Vascular access in hemodialysis patients older than 80 years.

OBJECTIVE There is a worldwide surge in numbers of elderly people requiring hemodialysis accompanying the prevailing increase in longevity. There is a trend for central venous catheters to be preferentially placed in elderly patients, whereas others recommend routine use of grafts for surgical access. In our center, age has not been a consideration in deciding to construct arteriovenous access for hemodialysis. We reviewed our experience with arteriovenous access surgery in all hemodialysis patients aged 80 years and older to determine if this approach is justified in terms of patency and life expectancy. METHODS A retrospective study was made of all patients aged 80 years and older who had surgery from January 2005 to December 2009 at our national vascular access referral center. All patients had preoperative mapping and had fistula construction if the vein size was at least 3 mm. Otherwise they had brachiobasilic or brachioaxillary grafts. All patients had routine access surveillance by Doppler ultrasound (duplex) and physical examination at regular intervals, and interventions were carried out according to the findings. Type of access, success rate, maturation, primary and secondary patency, and patient survival in the age group older than 80 years were noted. RESULTS During the study period, 134 patients had 146 new accesses. There were 128 autogenous accesses (30 forearm, 91 upper arm, and seven transposed basilic veins) and 18 prosthetic accesses. Overall primary patency was 39%, 33%, and 23% at 12, 24, and 36 months. Secondary patency was 92%, 83%, and 77% at 12, 24, and 36 months. There was no significant difference in patency between the different types of accesses and between diabetic and nondiabetic patients. Eleven upper arm and four forearm fistulas had delayed maturation or nonmaturation. The relative risk for delayed maturation or nonmaturation of forearm fistulas (13.3%) compared with brachial-cephalic fistula (12.1%) was 1.1030 (95% confidence interval, 0.3973-3.204; P = .8571). Median patient survival was 38 months, with 49 dying during follow-up. CONCLUSIONS Contrary to recent recommendations favoring grafts for hemodialysis in patients older than 80 years, most elderly patients in this study were found to have vasculature that was suitable for autogenous access construction, with patency rates similar to those of their younger counterparts when adequate preoperative planning and postoperative maintenance were carried out. Age alone should not disqualify patients older than 80 years from access surgery for hemodialysis, nor should age disqualify these patients from the Fistula First Initiative.

A prospective randomized study of heparin-bonded graft (Propaten) versus standard graft in prosthetic arteriovenous access

OBJECTIVE Prosthetic grafts continue to be required for hemodialysis access when the options for native fistulas have been exhausted. The inferior long-term patency of grafts makes the possibility of preventing occlusion with heparin-bonded grafts an attractive alternative. We carried out a prospective randomized study to compare the patency of standard grafts with heparin-bonded grafts. METHODS Patients with end-stage renal failure requiring a prosthetic access were randomized to receive either a standard expanded polytetrafluorethylene (ePTFE) graft or a heparin-bonded ePTFE graft. Patients were enrolled from June 2007 until November 2011 and were followed up until July 2013, when the study concluded. RESULTS In this study, 160 patients were randomized and followed up for a median of 23.5 months. No patient was lost to follow-up. Primary patency was 35% and 14% for heparin-bonded grafts and 29% and 12% for standard ePTFE grafts at 6 and 12 months, respectively (P = .48). Assisted primary patency was 54%, 41%, and 27% for heparin-bonded grafts and 41%, 30%, and 23% for standard grafts at 12, 24, and 36 months, respectively (P = .12). Secondary patency was 83%, 83%, and 81% for heparin-bonded grafts and 81%, 73%, and 68% for standard grafts at 12, 24, and 36 months, respectively (P = .33). There were significantly fewer thromboses in heparin-bonded grafts during the first 5 months (P = .020). Of 80 standard grafts, 24 were eventually abandoned vs 17 heparin-bonded grafts (P = .188). Bleeding complications, infections, and intervention rates were similar in both groups. CONCLUSIONS Heparin-bonded grafts demonstrated a trend to improved patency, but the difference was not statistically significant. Heparin-bonded grafts had a significantly lower early thrombosis rate that was sustained only for the first 5 months of follow-up.

Stent Grafts for Central Venous Occlusive Disease in Patients with Ipsilateral Hemodialysis Access

PURPOSE To assess long-term outcomes of stent grafts in patients with symptomatic central venous stenoses and occlusions ipsilateral to hemodialysis grafts or fistulas. MATERIALS AND METHODS The study included 52 of 55 consecutive patients with symptomatic stenoses of the central veins draining upper limb dialysis access grafts or fistulas treated with stent grafts. Indications for stent grafts were poor angioplasty results, rapid recurrence, or total occlusion. Endpoints were lesion patency and access patency following intervention. Mean follow-up was 25 months with a median of 24 months and 1.25 additional procedures per patient year. Patency rates were calculated using Kaplan-Meier analysis. RESULTS All stent grafts were successfully deployed. The lesion patency rates at 6, 12, 24, and 36 months after intervention were 60%, 40%, 28%, and 28%. The access patency rates at 6, 12, 24, and 36 months after intervention were 96%, 94%, 85%, and 72%. There was one major complication and no minor complications. In 40 patients (77%), the internal jugular vein confluence was covered by the stent graft. In five patients, the dialysis circuits became occluded, with no clinical sequelae in four; one patient was lost to follow-up. The contralateral brachiocephalic vein was covered in three patients (6%), preventing contralateral access construction in one patient. CONCLUSIONS Central vein stent graft placement in patients with hemodialysis access is associated with prolonged access patency. Coverage of major vein confluences, which occurred in 83% of the patients in this series, can compromise future access and should be avoided whenever possible by careful technique.

Anesthesia for vascular access surgery

The type of anesthesia chosen is an integral part of the decision-making process for arteriovenous access construction. We discuss the different types of anesthesia used, with emphasis on brachial plexus block, which is potentially safer than general anesthesia in this fragile patient population with end-stage renal disease. Brachial plexus block is superior to local anesthesia and enables the use of a tourniquet to minimize potential damage to the blood vessels during anastomosis using microsurgery techniques, and does not lead to the vasospasm that may be seen with local anesthesia. Regional anesthesia has a beneficial sympathectomy-like effect that causes vasodilation with increased blood flow during surgery and in the fistula postoperatively that may prevent early thrombosis and potentially improve outcome.

Banding between dialysis puncture sites to treat severe ischemic steal syndrome in low flow autogenous arteriovenous access

Dialysis-associated steal syndrome with rest pain and ischemic nonhealing ulcers dictates prompt surgical intervention. Distal revascularization with interval ligation is extensive surgery for frail patients in whom calcified distal arteries make anastomosis difficult. Simple banding is appropriate in high-flow fistulas. In low-flow accesses, further flow reduction by simple banding may result in inadequate dialysis and cause thrombosis. However, banding between puncture sites maintains a pressure gradient between the arterial and venous puncture sites that enables adequate flow with effective hemodialysis that would not be possible with banding at the anastomosis. This new technique is a good solution for maintaining access patency and increasing digital pressure while avoiding complicated surgical revisions in high-risk patients.

Heparin-bonded expanded polytetrafluorethylene grafts in hemodialysis access

When options for autologous arteriovenous (AV) fistulas have been fully exhausted, AV grafts continue to play an important role in access creation for hemodialysis, offering long-term hemodialysis access that is a better alternative to central vein catheters. The drawbacks of AV grafts are their poor patency, infection and higher cost. Their main advantages are that they are widely available, are easy to create, and mature early. In the context of the “Fistula First” initiative, many patients with low quality veins suffer from fistula failure and non-maturation resulting in prolonged catheter days that would otherwise be prevented by initial creation of an AV graft. Endeavors to improve graft patency include administration of pharmacological agents, changing graft configuration, altering graft biology, and altering the graft surface. In this review, the current status of heparin-bonded AV grafts for hemodialysis is discussed.

Upper limb grafts for hemodialysis access

Arteriovenous (AV) grafts are required for hemodialysis access when options for native fistulas have been fully exhausted, where they continue to play an important role in hemodialysis patients, offering a better alternative to central vein catheters. When planning autogenous accesses using Doppler ultrasound, adequate arterial inflow and venous outflow must be consciously preserved for future access creation with grafts. Efforts to improve graft patency include changing graft configuration, graft biology and hemodynamics. Industry offers early cannulation grafts to reduce central catheter use and a bioengineered graft is undergoing clinical studies. Although the outcome of AV grafts is inferior to fistulas, grafts can provide long-term hemodialysis access that is a better alternative to central venous catheters. AV grafts have significant drawbacks, mainly poor patency, infection and cost but also have some advantages: early maturation, ease of creation and needling and widespread availability. The outcome of AV graft surgery is variable from center to center. The primary patency rate for AV grafts is 58% at 6 months and the secondary patency rate is 76% at 6 months and 55% at 18 months. There are centers of excellence that report a 1 year secondary patency rate of up to 91%. In this review of the use of AV grafts for hemodialysis access in the upper extremities, technical issues involved in planning the access and performing the surgery in its different configurations are discussed and the role of surveillance and maintenance with their attendant surgical and radiological interventions is described.

The patient's role in patient safety and the importance of a dedicated vascular access team.

The role of dialysis patients in ensuring their own safety throughout the process of vascular access construction should be far from negligible. Patients can make important contributions to their safety starting in the predialysis stage, via vascular access construction and through the experience of chronic hemodialysis. Currently, patients assume a passive role and their empowerment requires both patients and caregivers to overcome many personal and cultural barriers, thus encouraging safety-related behavior. There are many opportunities for end-stage renal failure patients to be involved in every stage of their disease. In this chapter, we discuss how hemodialysis patients can participate in patient safety, including some of the main opportunities for involvement along the care pathway from the point at which the decision is made that the patient requires vascular access surgery.