Stent graft versus balloon angioplasty for failing dialysis-access grafts.

BACKGROUND: The leading cause of failure of a prosthetic arteriovenous hemodialysis-access graft is venous anastomotic stenosis. Balloon angioplasty, the first-line therapy, has a tendency to lead to subsequent recoil and restenosis; however, no other therapies have yet proved to be more effective. This study was designed to compare conventional balloon angioplasty with an expanded polytetrafluoroethylene endovascular stent graft for revision of venous anastomotic stenosis in failing hemodialysis grafts. METHODS: We conducted a prospective, multicenter trial, randomly assigning 190 patients who were undergoing hemodialysis and who had a venous anastomotic stenosis to undergo either balloon angioplasty alone or balloon angioplasty plus placement of the stent graft. Primary end points included patency of the treatment area and patency of the entire vascular access circuit. RESULTS: At 6 months, the incidence of patency of the treatment area was significantly greater in the stent-graft group than in the balloon-angioplasty group (51% vs. 23%, P<0.001), as was the incidence of patency of the access circuit (38% vs. 20%, P=0.008). In addition, the incidence of freedom from subsequent interventions at 6 months was significantly greater in the stent-graft group than in the balloon-angioplasty group (32% vs. 16%, P=0.03 by the log-rank test and P=0.04 by the Wilcoxon rank-sum test). The incidence of binary restenosis at 6 months was greater in the balloon-angioplasty group than in the stent-graft group (78% vs. 28%, P<0.001). The incidences of adverse events at 6 months were equivalent in the two treatment groups, with the exception of restenosis, which occurred more frequently in the balloon-angioplasty group (P<0.001). CONCLUSIONS: In this study, percutaneous revision of venous anastomotic stenosis in patients with a prosthetic hemodialysis graft was improved with the use of a stent graft, which appears to provide longer-term and superior patency and freedom from repeat interventions than standard balloon angioplasty. (ClinicalTrials.gov number, NCT00678249.)

Early use conversion of the HeRO dialysis graft.

Although more challenging to place, the HeRO device (Hemosphere Inc, Eden Prairie, Minn) provides the dialysis access-challenged patient the opportunity to have an upper extremity graft rather than being dependent on a catheter or requiring a lower extremity access. A major difficulty with the HeRO is the need for a concomitant dialysis catheter until the graft matures. This has been associated with a large number of bacteremia episodes. Currently available early-access grafts have patency rates similar to standard polytetrafluoroethylene. We have modified the HeRO insertion technique to combine its attributes with those of an early-use graft. In the five patients presented in this report, we confirm that this new technique can give the patient a graft that is functional ≤72 hours and obviate the need for a concomitant catheter. This results in an infection-free access over the follow-up period.

Graft for immediate use as first stage of a native fistula.

The majority of patients in the United States begin hemodialysis with a catheter. Many have immature or inadequate fistulae. At 90 days 77% of these patients are still using a catheter or a graft. The morbidity and mortality from prolonged catheter use have been well delineated. Although most of us adhere to the DOQI and Fistula First tenets, a fistula at all costs can seem counterproductive. A new paradigm is needed. The techniques described in this paper offer a novel approach to circumvent the problems of increasing catheter use and long fistula maturation times. The graft for immediate use is placed in the forearm and allows the proximal vessels to mature while providing dialysis access without a catheter. When these vessels meet maturation guidelines, or when surveillance indicates impending graft failure, a native fistula can be constructed and used in a 2-3 week period. This approach minimizes or circumvents catheter use altogether.

Use of bovine carotid artery for buttonhole technique hemodialysis.

PURPOSE: Assess the feasibility of using a bovine carotid artery graft for buttonhole technique hemodialysis in patients who are not candidates for a native fistula. METHODS: Case reports used to demonstrate selection criteria and results for this approach. Criteria include: knowledgeable patient with prior dialysis experience, stable graft in place for 3 months minimum, not a candidate for a native fistula, and able to maintain close follow-up. RESULTS: Both grafts were based on axillary vessels and have been in place for a total of 64 months. They have been used for dialysis via buttonhole for a total of 40 months. There have been three procedures on these patients, post-buttonhole use (.87/year). There have been no infections. CONCLUSIONS: These patients were carefully selected based on desire, support, knowledge/experience and ability. Their success suggests that buttonhole technique for hemodialysis on a synthetic semi-biologic graft can be accomplished with morbidity and longevity similar to any graft using non-buttonhole needle access.

Management of Primary Hyperparathyroidism: Can We Do Better?

The failure to follow national guidelines in management of various diseases has been previously established. We sought to quantify primary care providers' familiarity with primary hyperparathyroidism as it affects adherence to the 2009 National Institute of Health (NIH) consensus recommendations in treatment of primary hyperparathyroidism. A large primary care group was surveyed to determine their familiarity with the 2009 NIH consensus recommendations for management of primary hyperparathyroidism (PHPT). Retrospective review of the group's records (2009-2011) was performed to verify compliance. Survey responders included 109 clinicians, 31 per cent were familiar with all criteria for surgical intervention in asymptomatic patients and 34 per cent correctly identified appropriate surveillance testing for patients undergoing observation. Chart review identified 124 patients with PHPT. Of the patients who met NIH criteria, 34 per cent had a parathyroidectomy. Younger age, higher intact parathyroid hormone, hypercalciuria, and history of nephrolithiasis were associated with surgery in multivariable analysis. Of the observed patients, 16 per cent had appropriate surveillance studies. In conclusion, this study confirms suboptimal adherence with consensus recommendations in management of PHPT. A minority of clinicians demonstrated solid familiarity with management strategies, paralleling their treatment approach. Educational efforts may improve adherence with upcoming national recommendations.

Achieving vascular access success in the quality outcomes era.

BACKGROUND: In 1997 the National Kidney Foundation put forth guidelines for hemoaccess through its Dialysis Outcomes Quality Initiative (DOQI). Some centers have been able to meet these standards; most have not. METHODS: A retrospective review was made of our database of more than 3,500 hemoaccess procedures from 1986 to 2003. RESULTS: Our approach, increased use of transposed fistulas and preoperative duplex mapping, has led to a fistula incidence (84%) and prevalence (54%) exceeding DOQI criteria. Meeting the DOQI guideline for thrombectomy rate (0.5 per year) is mostly achieved by increased use of fistulas. Additionally, access monitoring, as well as intraoperative angiography, angioplasty, stenting, and surgical revision, can aid in decreasing the frequency of occlusions (0.45 per year). This operative approach has led to a 98% success rate for surgical thrombectomy, exceeding the DOQI guideline of 85%. Earlier referrals from nephrologists have lowered the catheter use prevalence to 9%. CONCLUSIONS: An aggressive approach to placing fistulas, maintaining the access, and receiving prompt referrals can lead to success in meeting DOQI criteria.

Treatment strategies for primary hyperparathyroidism: what is the cost?

Primary hyperparathyroidism (HPT) contributes to the onset of many chronic conditions. Although parathyroidectomy is the only definitive treatment, observation remains a valid option. Over a 3-year span, a major health plan was queried for HPT and benign parathyroid neoplasm. Patients with secondary and tertiary HPT, Stage III to V kidney disease, and prior renal transplant were excluded. Patients were divided into: observation (Group 1), parathyroidectomy during the study period (Group 2), and parathyroidectomy before the study group (Group 3), and were compared with a control group of 27,092 adult members without HPT using analysis of variance. The 3-year mean total allowed expenditure for Group One (n = 559), Group Two (n = 93), and Group Three (n = 48) were $21,267, $37,043, and $14,702, respectively. Groups One and Two had significantly higher use than the nonparathyroid group (P < 0.0001), whereas that of Group Three was comparable. Group Two had the highest cost, whereas Group Three had a significantly lower cost than Group One (P 0.0001). Primary hyperparathyroidism is associated with a higher use of healthcare resources. Patients observed incurred a higher allowed expenditure than those with prior parathyroidectomy. Surgical treatment may represent a cost-effective strategy for treatment of hyperparathyroidism, although more comprehensive studies are needed to confirm these findings.

Outpatient thyroidectomy: is it a safe and reasonable option?

BACKGROUND: Outpatient surgery is cost effective and convenient. The aim of this study was to determine the safety and feasibility of outpatient thyroidectomy. METHODS: Retrospective review was performed of all thyroidectomy patients from a tertiary care center between January 2004 and March 2010. RESULTS: One hundred forty-eight patients met the inclusion criteria. Subtotal and hemithyroidectomies (n = 79) were compared against completion and total thyroidectomies (n = 72). Nine total thyroidectomy patients (12.5%) required unplanned overnight admission, compared with 4 hemithyroidectomy patients (5.1%) (P = .15). The majority were admitted for pain and nausea control. Overnight admissions were highest among men (32% vs 5%, P = .002) and patients with Graves' disease (36% vs 6%, P = .003). Postoperative complications occurred in 6 total thyroidectomy patients (8.3%) and 3 hemithyroidectomy patients (3.8%) (P = .31). Only 4 patients (2.6%) required readmission for complications. There were no deaths. CONCLUSIONS: Outpatient thyroidectomy performed by an experienced surgeon is safe and feasible. Men and patients with Graves' disease have a higher probability of requiring postoperative admission.

Early cannulation prosthetic graft (Flixene™) for arteriovenous access.

PURPOSE: Preferred hemodialysis (HD) access is an autologous fistula. Vascular grafts are used in patients with vessels unsuitable to accomplish an arteriovenous fistula (AVF). It is recommended that most current grafts mature in situ for 2-3 weeks before being accessed. Graft complications occur because the structure was not designed for the trauma of repeated cannulation. This study graft has a different structure that enables early use. Its design minimizes weeping through the graft walls and is meant to endure repeated access, thus minimizing the use of HD catheters. The purpose of this study was to show that the Flixene™ graft can be safely placed in patients where fistulas have failed and can be cannulated in 24-72 hr, while maintaining patency rates similar to other polytetrafluoroethylene (PTFE) grafts on the market. Flixene™ configuration should also reduce the incidence of pseudoaneurysms and seromas. METHODS: A prospective two-center study placed 33 grafts in 33 patients; graft efficacy, post-operative complications, and patency were evaluated. Ease of cannulation and dialysis center complications related to early cannulation were documented. Six month follow-up data was analyzed. RESULTS: Successful access was achieved in all 33 patients within 72 hr (29 patients within 24 hr). Overall primary patency at 6 months was 49%; primary-assisted patency at 6 months was 80%. No pseudoaneurysms or seromas were documented at 6 months. Complications were typical of graft access. CONCLUSION: Early cannulation was successful in all patients. Primary and secondary patency rates at 6-months were equivalent to other data reported on PTFE grafts. Flixene™ successfully prevented pseudoaneurysm and seroma formation at 6 months of prospective follow-up. This graft is a better last-resort option for patients who cannot receive a fistula, compared to double-lumen cuffed catheters.

Sirolimus-loaded polyurethane graft for hemodialysis access in sheep.

Intimal hyperplasia is the most common final pathway for hemoaccess occlusion in dialysis patients. Drug eluting stents have been shown to decrease intimal hyperplasia in coronary arteries and possibly in peripheral arteries. We evaluated the use of a sirolimus loaded polyurethane graft as prophylaxis in hemodialysis access. Grafts were loaded with sirolimus and elution curves were determined for the polyurethane material. The arteriovenous grafts were then placed in the neck of 20 sheep. A non-loaded graft was placed in the contralateral neck. Patency rates, ultrasound evaluation, angiography and histomorphometry were determined for each graft. At 30, 60 and 90 days the drug loaded graft had improved patency rates compared to the control, with a 25% improvement noted at 3 months. Life table analysis showed the drug loaded graft consistently better patency than the control (p=.136). The control graft had greater neointimal stenosis (14.5% vs. 9.17%) over the course of the study (p=.157). Although none of these findings was statistically significant in this pilot study, the sirolimus coated graft out-performed the control in every measured parameter at each time point evaluated. Further work to asses the validity of drug coated materials to prevent intimal hyperplasia in hemodialysis access is warranted.

Comparison of clinical assessment with ultrasound flow for hemodialysis access surveillance.

HYPOTHESIS: Organized clinical assessment of hemodialysis access is as useful a surveillance tool as ultrasound flow measurements in preventing access thrombosis. DESIGN: Cohort analysis comparing a dialysis unit evaluated using ultrasound flow measurements with another unit evaluated clinically. SETTING: University-affiliated community program with private and health maintenance organization dialysis units. PATIENTS: One hundred patients in each unit were enrolled. Patients who were unavailable for follow-up or died within the first 30 days of enrollment were excluded from further analysis. INTERVENTION: Angiograms were obtained in the Transonics Doppler ultrasound system (Transonics Systems Inc, Ithaca, New York) cohort if graft flow was less than 600 mL/min, fistula flow was less than 450 mL/min, or flow decreased more than 25%, and in the clinical cohort if there was a change in the access appearance, change in the bruit, or a sharp increase in venous resistance. MAIN OUTCOME MEASURES: Primary and secondary patencies of the hemodialysis access were analyzed for each cohort. Subset analysis was obtained for synthetic grafts and native fistulas. Procedures were assessed for each cohort. RESULTS: The patients in the clinical cohort had similar primary patency (1199 days) as in the Transonics cohort (1162 days) (P = .92). Angiographic procedures were also similar, with 56% of all patients having none. The mean number of procedures was 0.56 per patient in the Transonics cohort and 0.48 in the clinical group (P = .48). CONCLUSION: An organized clinical assessment, using a formal tracking tool, is equal to ultrasound flow measurements as a surveillance method to prevent hemodialysis access thrombosis.

Dose-ranging trial with a recombinant urokinase (urokinase alfa) for occluded central venous catheters in oncology patients.

PURPOSE: Recombinant urokinase (r-UK) is a high-molecular-weight urokinase produced in transfected, non-human, mammalian cells. A Phase II, randomized, double-blind, parallel, placebo-controlled, dose-ranging study was performed to compare the safety and efficacy of one or two instillations of three intraluminal concentrations of r-UK (5,000; 15,000; and 25,000 IU/mL) with a placebo for reestablishment of total function to occluded central venous access devices (CVADs). MATERIALS AND METHODS: One-hundred eight patients with CVAD withdrawal or total occlusion were enrolled and randomized to treatment; 104 patients received at least one instillation of study drug and 101 patients completed treatment. All but one patient had cancer. RESULTS: All three concentrations of r-UK were significantly superior to placebo in restoring total CVAD function (patency of all occluded lumens) after one or two instillations of study medication (25,000 IU/mL r-UK, 68% vs. placebo, 28% [P =.007]; 15,000 IU/mL r-UK, 69% vs. placebo, 24% [P =.004]; 5,000 IU/mL r-UK, 70% vs. placebo, 28% [P =.003]). Comparisons of the three r-UK concentrations indicated no difference after one or two instillations with regards to patency restoration. Treatment-emergent hemorrhagic events occurring within 72 hours after study drug exposure were experienced by four patients (17%) in the 25,000 IU/mL r-UK group, two patients (7%) in the 15,000 IU/mL r-UK group, no patients in the 5,000 IU/mL r-UK group, and no patients in the placebo group. CONCLUSIONS: Efficacy and safety results of this study support further evaluation of a 5,000 IU/mL concentration of r-UK for treatment of occluded CVADs in adult and pediatric patients from 1 year of age.