Direct Arteriovenous Communication Angioaccess Blair Keagy A major focus of the kidney disease outcomes and quality initiative is the creation of the national vascular access improvement initiative with a “fistula first” campaign. A goal of 66% prevalence of arteriovenous fistulas (AVFs) was suggested for 2009. This has resulted in an increase in the number of fistulas placed by access surgeons. However, this might not be the best approach for all patients undergoing dialysis. Biuckians and colleagues reviewed their experience with AVFs and showed that if an AVF was successfully used for hemodialysis, there was an average requirement of 5 months prior to cannulation. In addition, of those that functioned, only two thirds were working at the end of 1 year. We have a policy of preoperative vein mapping for our dialysis patients and tend not to use a vein unless it is greater than 2 mm in diameter. At many institutions, fistulas are not placed in a timely fashion. This is one of the causative factors contributing to the fact that approximately 60% of patients in the United States begin hemodialysis by means of a catheter. The use of catheters, as opposed to fistulas, has been associated with as much as a three times greater mortality rate and higher health care expenditures. A fistula should be placed before the patient begins dialysis, with the goal of avoiding the placement of a dialysis catheter. Thus, optimal timing of fistula placement is extremely important and may be aided by employment of a nurse coordinator dedicated to all aspects of the care of a patient with kidney failure. Preoperative Evaluation One determinant, possibly the most important, of a successful vascular access surgery is the preoperative planning. With the availability of imaging modalities, a patient should never be subjected to exploration of various vessels at the time of surgery to determine an appropriate location. A preoperative ultrasound evaluation of the upper extremity yields important data that are used in procedural planning. Information obtained includes size and patency of the radial, ulnar, and brachial arteries; presence of calcium or shadowing in the artery; diameter, depth, and patency of the cephalic and basilic veins; and presence or absence of central vein stenosis. Vein diameter is a major predictor of the maturation process of a fistula. In many instances a fistula can be technically constructed, but it will not mature because of the size of the vessels involved. Data from our institution demonstrate that fistulas established using a vein less than 2 mm in diameter portends a poor outcome. Some researchers feel that the primary failure rate in the fistula-first era is a result of artery size rather than vein size. Of equal importance is the condition of the artery. Severe calcification, as identified by ultrasound, can indicate difficulties in performing the anastomosis, thus adversely affecting patency. In patients who have had any type of central venous catheter for longer than 6 weeks or who have had multiple catheters, there is a risk of central venous stenosis. These central veins cannot always be assessed with ultrasound; therefore, a central venogram should be obtained to verify the absence of ipsilateral obstruction. Failure to adequately assess both the arterial and venous systems before forming the fistula can lead to prolonged or failed maturation, decreased patency rates, and increased catheter use. Location of the Fistula In the upper extremity a fistula may be constructed using the radial artery at the wrist, proximal radial artery, ulnar artery, or brachial artery. Upper extremity veins commonly include the cephalic vein at various locations, the basilic vein with transposition, and the brachial vein with transposition. It is important to select the appropriate vascular access based on careful preoperative planning and not only to consider the first procedure but also to have a long-term, stepwise plan for possible multiple access procedures. Some authors recommend starting as distally as possible in the extremity, thus allowing the construction of a more proximal fistula in case of failure. In general, the nondominant arm should be employed in case any untoward events such as hand ischemia occur. The radial artery is often used as the initial site for an arteriovenous fistula, including a snuffbox fistula, a wrist radiocephalic fistula, or a forearm radiocephalic fistula. Also, an anastomosis between the ulnar artery and the basilic vein below the antecubital fossa may be used on occasion. Basilic vein transposition has been used successfully in many cases. This is a more difficult operation because complete mobilization of the basilic vein is generally required. Basilic vein transposition in one or two stages is based on superficializing the basilic vein, which may be done at the time the initial fistula is created or as a second-stage procedure. However, patency rates are good and this may be a successful way of salvaging a fistula in a patient in whom a more proximal construction has failed. Brachial artery AVFs have a better patency rate than those constructed in the more distal radial artery. More creative ways can be used to establish a fistula, such as a transposed femoral vein anastomosed to the femoral artery. Only gold members can continue reading. 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Direct Arteriovenous Communication Angioaccess Blair Keagy A major focus of the kidney disease outcomes and quality initiative is the creation of the national vascular access improvement initiative with a “fistula first” campaign. A goal of 66% prevalence of arteriovenous fistulas (AVFs) was suggested for 2009. This has resulted in an increase in the number of fistulas placed by access surgeons. However, this might not be the best approach for all patients undergoing dialysis. Biuckians and colleagues reviewed their experience with AVFs and showed that if an AVF was successfully used for hemodialysis, there was an average requirement of 5 months prior to cannulation. In addition, of those that functioned, only two thirds were working at the end of 1 year. We have a policy of preoperative vein mapping for our dialysis patients and tend not to use a vein unless it is greater than 2 mm in diameter. At many institutions, fistulas are not placed in a timely fashion. This is one of the causative factors contributing to the fact that approximately 60% of patients in the United States begin hemodialysis by means of a catheter. The use of catheters, as opposed to fistulas, has been associated with as much as a three times greater mortality rate and higher health care expenditures. A fistula should be placed before the patient begins dialysis, with the goal of avoiding the placement of a dialysis catheter. Thus, optimal timing of fistula placement is extremely important and may be aided by employment of a nurse coordinator dedicated to all aspects of the care of a patient with kidney failure. Preoperative Evaluation One determinant, possibly the most important, of a successful vascular access surgery is the preoperative planning. With the availability of imaging modalities, a patient should never be subjected to exploration of various vessels at the time of surgery to determine an appropriate location. A preoperative ultrasound evaluation of the upper extremity yields important data that are used in procedural planning. Information obtained includes size and patency of the radial, ulnar, and brachial arteries; presence of calcium or shadowing in the artery; diameter, depth, and patency of the cephalic and basilic veins; and presence or absence of central vein stenosis. Vein diameter is a major predictor of the maturation process of a fistula. In many instances a fistula can be technically constructed, but it will not mature because of the size of the vessels involved. Data from our institution demonstrate that fistulas established using a vein less than 2 mm in diameter portends a poor outcome. Some researchers feel that the primary failure rate in the fistula-first era is a result of artery size rather than vein size. Of equal importance is the condition of the artery. Severe calcification, as identified by ultrasound, can indicate difficulties in performing the anastomosis, thus adversely affecting patency. In patients who have had any type of central venous catheter for longer than 6 weeks or who have had multiple catheters, there is a risk of central venous stenosis. These central veins cannot always be assessed with ultrasound; therefore, a central venogram should be obtained to verify the absence of ipsilateral obstruction. Failure to adequately assess both the arterial and venous systems before forming the fistula can lead to prolonged or failed maturation, decreased patency rates, and increased catheter use. Location of the Fistula In the upper extremity a fistula may be constructed using the radial artery at the wrist, proximal radial artery, ulnar artery, or brachial artery. Upper extremity veins commonly include the cephalic vein at various locations, the basilic vein with transposition, and the brachial vein with transposition. It is important to select the appropriate vascular access based on careful preoperative planning and not only to consider the first procedure but also to have a long-term, stepwise plan for possible multiple access procedures. Some authors recommend starting as distally as possible in the extremity, thus allowing the construction of a more proximal fistula in case of failure. In general, the nondominant arm should be employed in case any untoward events such as hand ischemia occur. The radial artery is often used as the initial site for an arteriovenous fistula, including a snuffbox fistula, a wrist radiocephalic fistula, or a forearm radiocephalic fistula. Also, an anastomosis between the ulnar artery and the basilic vein below the antecubital fossa may be used on occasion. Basilic vein transposition has been used successfully in many cases. This is a more difficult operation because complete mobilization of the basilic vein is generally required. Basilic vein transposition in one or two stages is based on superficializing the basilic vein, which may be done at the time the initial fistula is created or as a second-stage procedure. However, patency rates are good and this may be a successful way of salvaging a fistula in a patient in whom a more proximal construction has failed. Brachial artery AVFs have a better patency rate than those constructed in the more distal radial artery. More creative ways can be used to establish a fistula, such as a transposed femoral vein anastomosed to the femoral artery. Only gold members can continue reading. Log In or Register to continue Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Related posts: Technical Aspects of Percutaneous Carotid Angioplasty and Stenting for Arteriosclerotic Disease In-Situ Treatment of Aortic Graft Infection with Prosthetic Grafts and Allografts Treatment of Acute Upper Extremity Venous Occlusion Intraoperative Assessment of the Technical Adequacy of Carotid Endarterectomy Stay updated, free articles. Join our Telegram channel Join
