Page 413 - Libro 2

26
Hemodialysis Access Grafts and Fistulae
Michael J. Singh and Cheryl Sura
OBJECTIVES
Describe the difference between an arteriovenous fistula and graft
Identify the duplex findings of a normal arteriovenous fistula
Define normal venous and arterial anatomy in the upper extremity
Describe the venous Doppler findings in an occluded axillary vein
Demonstrate proper probe positioning for imaging a radiocephalic fistula
Differentiate a forearm graft from a brachiocephalic fistula
Quantify the degree of stenosis based on Doppler findings
KEY TERMS
arteriovenous fistula | arteriovenous graft | hemodialysis access
GLOSSARY
arteriovenous fistula an abnormal connection between an artery and vein; this may be congenital or acquired; one type of acquired arteriovenous fis- tula is surgically created to allow for hemodialysis
arteriovenous graft a type of hemodialysis ac- cess that uses a prosthetic conduit to connect an artery to a vein to allow for dialysis
Due to various factors, the incidence of chronic kidney disease and end-stage renal disease are be- coming more prevalent in the United States. In 2005, the Renal Data System determined that more than 106,000 patients began hemodialysis and the total number of people undergoing hemodialysis had reached 341,000. The National Kidney Foundation Kidney Disease Outcomes Quality Initiative was published in 1997 and recommended that 50% of future hemodialysis access be constructed with au- togenous arteriovenous access. In 2005, the Centers for Medicare and Medicaid Services (CMS) promoted the Fistula First Breakthrough Initiative. The goal of this was to expand the creation of new autogenous access to 66% by 2009.1
The goal of arteriovenous (AV) access is to provide long-term hemodialysis access with a low frequency of reintervention and a low complication rate. The
hemodialysis access also known as vascular access; a surgically created connection between an artery and vein to allow for the removal of toxic products from the blood by dialysis
tenet for hemodialysis access is to create an autoge- nous fistula as far distally as possible in the nondom- inant arm. This technique preserves the proximal vessels for future access and allows the individual to carry out normal daily activities. Autogenous access has been the preferred first line of therapy because it has superior patency rates and lower complication rates compared to prosthetic grafts.2 Upper extrem- ity access is preferred; it maintains a lower infection rate and provides easier access for hemodialysis. A native AV fistula is a surgically created anastomo- sis between an artery and a vein. When fistula cre- ation is not possible, a prosthetic graft is often used to connect the two vessels. These prosthetic grafts are made of polytetrafluoroethylene (PTFE) and tun- neled in the subcutaneous tissue.
Failure of an AV fistula to mature and throm- bose are frequent indications for reintervention.
393