High brachial artery bifurcation: clinical considerations and practical implications for an arteriovenous access.

High brachial artery bifurcation (HiBAB) is not a rare occurrence. Recent data have emphasized that HiBAB can have major clinical implications including high failure rate and decreased functional patency of an arteriovenous (AV) fistula. In this retrospective study, we investigated the incidence of HiBAB. Patients with advanced chronic kidney disease and end-stage renal disease on chronic hemodialysis undergoing preoperative vascular mapping for the creation of an AV access were included in this analysis. Ultrasound examination was used to map the arteries of the upper extremities. Four hundred and eighty-one arms in 340 patients were examined (right arm = 181, left arm = 300). Sixty-nine of the 481 (12.3%) demonstrated HiBAB. The internal diameter of the radial and ulnar arteries measured at the elbow region was found to be 2.9 ± 0.8 and 3.6 ± 1.0 mm, respectively (p = 0.0001). There were no statistically significant differences in terms of race, gender, and right versus left arms regarding the incidence of HiBAB. As HiBAB can be present in a significant number of patients and have an impact on the AV access, its presence should be evaluated during vascular mapping prior to an AV access creation.

Status of research in vascular access for dialysis.

BACKGROUND: Vascular access issues impose a major financial burden to health care and can be associated with increased morbidity and mortality. In this context, strategies, guidelines and available published information become important tools for health-care facilities and workers. While published data form a sound basis of formulating clinical practice guidelines for vascular access (VA), quality of the medical information is critically important. This study investigates the current status of VA publications. METHODS: A PubMed search was performed to capture all articles related to dialysis vascular access published from January 1997 to December 2009. The articles were categorized by publication type, study subject, year of publication and specialty of the authors. RESULTS: A total of 2260 articles from 60 medical journals were identified. Insignificant publications (letters/communications, n = 125) were excluded from the analysis. Therefore, 2135 articles formed the basis for analysis. Sixteen of the 60 journals routinely published on vascular access and generated 1747 articles [nephrology = 7 (publications = 782); radiology = 4 (publications = 333); surgery = 5 (publications = 486)], while 44/60 journals published scarcely and produced 388 articles over the 13-year period. Overall, 1213 (57%) of the articles were published by the direct involvement of nephrologists [nephrologists alone (n = 564); nephrologists in collaboration with others (n = 649)]. There were 1194 observational studies, 444 case reports/series, 375 review/editorials, 51 basic research, 12 meta-analyses and 59 randomized controlled trials published over the 13-year period. The average impact factor for nephrology, radiology and surgery journals that routinely published on vascular access was 4.425, 3.099 and 2.679, respectively. CONCLUSIONS: Despite an increased rate of scholarly activity in the area of vascular access, there remains a significant challenge ahead due to the lack of randomized controlled trials and research focusing on the biology of vascular access stenosis.

Cephalic arch stenosis.

The Kidney Dialysis Outcomes Quality Initiative guidelines and the Fistula First Initiative for vascular access have had a measurable impact on the incidence and prevalence of the type of access used to deliver hemodialysis in the United States. There has been a yearly increase in the placement of arteriovenous fistulas and an exponential increase in endovascular treatment of failing and immature fistulas. Undoubtedly, the predominant cause of fistula malfunction is stenosis within the access system. The stenotic lesions can occur anywhere within the access system from the arteries to the outflow and central veins. One of the relatively common sites for stenosis in patients with brachiocephalic fistulas is the cephalic arch region. While access stenoses at many other sites have been successfully treated with percutaneous balloon angioplasty, the results of this approach in the management of cephalic arch stenosis (CAS) have been rather disappointing. This has been in part due to multiple factors including the resistant nature of the stenosis, the development of early restenosis, as well as poor patency and high vein rupture rates. This article discusses the anatomy, postulated etiology and percutaneous interventions for the treatment of CAS. In addition, the report highlights surgical alternatives to the management of stenosis in this segment of the cephalic vein.

Role of surgical intervention for cephalic arch stenosis in the "fistula first" era.

Cephalic arch stenosis (CAS) is a frequent cause of vascular access dysfunction in patients with brachiocephalic fistulae. While percutaneous balloon angioplasty has been used to treat CAS, the results of this approach have been poor due to multiple factors including resistant nature of the stenosis, development of early restenosis, as well as poor patency and high vein rupture rates. In this analysis, we report the results of an alternative approach to manage this problem. Thirteen patients with frequently recurring CAS were referred for surgical intervention. Angiographic images recorded during the prior percutaneous procedures were made available to the surgeons. The surgical procedure entailed transecting the healthy portion of the cephalic vein distal to the stenotic segment in the arch, transposing and anastomosing it to the upper basilic/axillary vein. Following surgical revision, development of access dysfunction was treated with percutaneous balloon angioplasty. Patency rates for angioplasty before and after the surgical revision were evaluated. Primary patency rates for angioplasty before the surgical revision were 23%, 8% and 0% at 3, 6, and 12 months, respectively. Following surgical revision, all patients needed angioplasty procedure. However, primary patency increased to 92%, 69%, and 39% at 3, 6, and 12 months, respectively (p = 0.0001). Secondary patency before the surgical revision at 3, 6, and 12 months was 100%, 39%, and 8%, respectively, compared with 92% at 3, 6, and 12 months postsurgical revision (p = 0.0003). The results of this study demonstrate that surgical transposition of the cephalic vein in frequently recurring CAS is a viable option and yields better patency rates for future angioplasty procedures.

Efficiency and outcomes of emergent vascular access procedures performed at a dedicated outpatient vascular access center.

The outpatient vascular access center (VAC) may have an important impact in improving the outcomes of emergent procedures on nonfunctioning hemodialysis access. An emergent procedure is defined as the absence of a functioning access for hemodialysis, including thrombosed graft or fistula, nonfunctioning dialysis catheters, and the need for access to initiate emergent hemodialysis. The aim of this study was to prospectively evaluate the efficiency and outcomes of all consecutive emergent hemodialysis access procedures during a 3-month period at a single high volume VAC. Data collection for each procedure included anatomic outcome, clinical outcome, the amount of time from referral to procedure and to successful dialysis, 2-week-follow-up to screen for postprocedure complications and fluoroscopy time. A total of 157 emergent procedures were performed in 136 patients with the majority of interventions on nonfunctioning grafts and tunneled catheters. The overall clinical success (defined as successful postprocedure completion of at least one dialysis treatment at the prescribed blood flow) was achieved in 149 out of 157 (95%) cases. 90% of subjects completed their procedure within 24 hours of the initial referral to the VAC. The study also demonstrated a rapid turn around time, with successful dialysis being performed within 24 hours of referral in 61% and within 48 hours in 90% of referrals. This is the first study to demonstrate both the efficiency and successful outcomes of an outpatient vascular access center in treating emergent vascular access problems.

The new arteriovenous fistula: the need for earlier evaluation and intervention.

The National Kidney Foundation's Dialysis Outcomes Quality Initiative recommends an ideal 3- to 4-month arteriovenous fistula (AVF) maturation period prior to cannulation. This recommendation may be misinterpreted by practicing nephrologists to mean that they should wait 3 months before performing a clinical assessment of the AVF. Such a delay in evaluating AVF maturity results in unnecessarily prolonged catheter use in dialysis patients whose ultimately unsatisfactory fistula could already have been diagnosed and modified at a much earlier point. Clinical assessment at 1 month can detect the common etiologies for nonmaturity, including stenosis in the vein adjacent to the anastomosis and accessory vein diversion of flow from the main fistula vein. Duplex ultrasound provides additional information in selected cases. Early evaluation allows for early fistulography for problems and potentially early cannulation for adequately maturing fistulas. Prospective trials of early AVF clinical assessment at 1 month should be performed.