Unconventional Venous Access Procedures for Chronic Hemodialysis




Historical Background


Despite the success of the Brescia-Cimino type subcutaneous arteriovenous fistula in 1962, the absence of suitable forearm vessels in many patients led to the evaluation of alternative conduits. In 1969 May and colleagues described the creation of a forearm arteriovenous fistula using autogenous saphenous vein. This was soon followed by the evaluation of nonautogenous conduits, including the bovine carotid heterograft, as described by Chivitz and associates in 1972, and microporous expanded polytetrafluoroethylene (PTFE), which was first reported by Baker and co-workers in 1975. PTFE grafts, as either loop or straight arteriovenous conduits, was applied both in the upper and lower extremity in these early reports. In the decades that followed, patients presenting with limited vascular access options in the upper extremity continued to challenge surgeons with increasing frequency. Thus the use of unconventional sites and means of achieving vascular access for hemodialysis continued to be explored. Use of the anterior chest wall axillary artery and vein for arteriovenous access was reported by Ono and colleagues in 1995, and the transposition of the brachial vein in the upper extremity and saphenous vein in the lower extremity for henodialysis access described in 1998. Katzman and associates described their initial experience with the hybrid HERO graft-catheter vascular access device in 2009.




Indications


Although algorithms have been developed to define a general “order of preference” for access placement in the upper extremity, a similar algorithm for patients who require more complex access placement is problematic given the lack of evidence-based reports. It is possible, however, to provide recommendations for specific clinical situations in which a particular complex access procedure would be most helpful and in which it should be avoided. These recommendations are outlined in Table 66-1 .



TABLE 66-1

Considerations for Major Complex Access Procedures







































Access Procedure Indications Ideal Clinical Situations Relative Contraindications
Femoral or saphenous vein transposition Patent femoral or saphenous vein
Femoral or saphenous vein > 3 mm in diameter
Patent, noncalcific femoral artery
Pediatric or young healthy patients
Thrombophilia with no other autogenous access option
Patients at high risk for infection (poor hygiene, immunosuppressed, multiple previous access infections)
Significant obesity of the thigh
Patients who are medically fragile
Access sites for temporary catheter placement not readily available
Patients at high risk for access-related limb ischemia
Brachial vein transposition Brachial vein > 2.5 mm in diameter Pediatric or young healthy patient
Patients at high risk for infection (poor hygiene, immunosuppressed, multiple previous access infections)
Patients who are candidates for autogenous radial-cephalic, brachial-cephalic, or brachial-basilic access
Significant obesity of the upper arm
Prosthetic midthigh or proximal loop femoral-femoral access Patent femoral or common femoral vein
Patent, noncalcific superficial femoral artery (midthigh access), common femoral artery
Patients who are elderly or have significant medical comorbidities Patients at high risk for infection (poor hygiene, immunosuppressed, multiple previous access infections)
Patients who are morbidly obese
Prosthetic chest wall access Patent axillary or subclavian artery and vein
Patient central vein
Patients who are morbidly obese Patients who are reasonable candidates for an autogenous or prosthetic thigh access procedure
Transthoracic cuffed dialysis catheter Patent superior vena cava (long stump preferable)
Access to the superior vena cava via the femoral vein for pigtail catheter placement
Patients who have limited life expectancy (<6 months)
Patients for whom all alternative access procedures have been used
Patients who are candidates for an alternative complex access procedure
Patients who are candidates for cuffed dialysis catheter placement via the internal jugular or subclavian vein
Patients with severe cardiac or pulmonary disease
HERO device Patent central veins
Brachial artery anatomy suitable for arteriovenous access placement
Patients whose only option for chronic hemodialysis access is a tunneled cuffed dialysis catheter Patients who are candidates for an alternative complex access procedure




Preoperative Preparation





  • History. A complete history that specifies the presumed cause for prior vascular access failures requires a thorough review of operative notes, as well as consultation with treating nephrologists and dialysis nurses.



  • Preoperative imaging. Noninvasive vascular testing may not provide sufficient anatomic information for patients who have had multiple access procedures. Accordingly, contrast angiography may be required to identify arterial and venous pathology that may influence outcome.



  • Preoperative preparation. The patient’s medical condition should be optimized before surgery, including fluid status, which may require coordination with the treating nephrologist and the patient’s dialysis schedule. In addition, healing of all open wounds and resolution of coexistent infection, as well as stabilization of significant comorbid conditions that may increase anesthetic risk, should be undertaken before surgery. Preoperative vascular and neurologic status of the extremity should be documented.



  • Prevention of surgical site infection. Appropriate prophylactic antibiotics should be administered, and an antimicrobial adhesive film barrier should be applied over the operative field.





Pitfalls and Danger Points





  • Relevant vascular anatomy should be delineated.



  • Factors contributing to prior access failures, including undetected thrombophilia, should be identified. Strategies to prolong patency may include adjusting medications and the patient’s dry weight to minimize the risk of hypotension during or after hemodialysis. In addition, initiating anticoagulation therapy immediately after thrombectomy or access placement may be appropriate.



  • All access options must be considered to formulate a long-term vascular access strategy.





Operative Strategy


Options for Temporary Dialysis Access


Planning for the potential need for future access should begin long before surgical intervention is necessary. Strategic considerations should also include options for temporary access. If options for a temporary dialysis catheter are limited, an “early stick” vascular graft may be of value. If possible, catheters located at or near the region where new access is planned should be removed several days before the operative procedure.


Assessment of Remaining Options for Upper Extremity Access


The complication rate of vascular access in the lower extremity, chest wall, and other so-called exotic access sites is higher than in the upper extremity, and management of these problems can be challenging. Therefore one should ensure that alternative options in the upper extremity no longer exist. For example, a venogram may reveal paired brachial veins or an open cephalic vein in the deltopectoral groove, either of which could provide adequate venous outflow. Occasionally upper extremity arterial and venous anatomy is adequate, but an ipsilateral central venous stenosis or occlusion seemingly precludes vascular access. Although long-term durability of central vein angioplasty is modest, with primary patency rates of about 40% at 6 months, repeat angioplasty with or without stenting does extend secondary patency rates. Thus treatment of a central vein stenosis with a percutaneous intervention followed by placement of an upper extremity arteriovenous access site should be considered before proceeding to the thigh or chest wall. For patients who are obese, standard basilic, brachial, or femoral transpositions through a separate subcutaneous tunnel may be impractical because vein length will not be sufficient. However, a transposition may be possible if the vein is elevated into the incision.


The Pediatric Patient


For small children, peritoneal dialysis may be advisable. If necessary, hemodialysis via percutaneously or surgically placed catheters can be achieved, but infectious complications are common. Ideally, pediatric patients should receive an autogenous vascular access placed distally in the extremity. Microsurgical techniques, including the use of microsurgical instruments, interrupted sutures, and adequate magnification, greatly facilitate pediatric vascular access placement. To minimize vessel dissection and vasospasm, the use of a sterile tourniquet may be helpful.


Brachial Vein Transposition


Brachial vein transposition should be considered if vein diameter exceeds 2.5 mm on preoperative vein mapping and if a brachial-cephalic fistula or basilic vein transposition is precluded. Brachial vein transposition should be performed as a two-stage procedure, whereby the arteriovenous anastomosis is created first and is followed 6 weeks later by vein transposition. A one-stage procedure may be considered if the preoperative brachial vein diameter exceeds 4 mm. Obese patients with significant upper arm adipose tissue are not ideal candidates for brachial vein transposition because the vein length may be too short to transpose superficially.


Saphenous Vein Transposition


Use of skip incisions or endoscopic techniques to harvest the saphenous vein may decrease the risk of wound complications. Because the great saphenous vein does not readily dilate after creation of a fistula, only veins greater than 3 mm in diameter should be used. Cannulation of the access must be delayed at least 6 weeks postoperatively to avoid puncture site bleeding and hematoma. The procedure may not be practical for patients who are morbidly obese, because cannulation may require the patient to lie supine and to retract the pannus to expose the access site.


Prosthetic Lower Extremity Vascular Access


Sites used for prosthetic arteriovenous access in the lower extremity are the femoral artery to great saphenous or femoral vein loop access, and the midthigh, midsuperficial femoral artery to femoral vein loop access. Prosthetic access in the lower extremity is preferred once options in the upper extremity have been exhausted because of simplicity and accessibility of femoral vessels, with patency rates that are comparable if not superior to upper extremity procedures. In addition, graft infection and an anastomotic stenosis are easier to manage than if the access site is in the chest wall, and both hands are free to self-cannulate or to perform other activities during dialysis. By basing the arterial and venous anastomoses in the midthigh superficial femoral artery and femoral vein, node-bearing tissue and panniculus in the groin are avoided. As a result, prosthetic midthigh loop access appears to carry a lower infection rate compared with prosthetic procedures in the groin. The prosthetic midthigh loop access also preserves proximal femoral vessels for future access placement. Preoperative duplex ultrasonography should be performed to verify patency of both artery and vein, as well as to determine the degree of calcification in the arterial wall.


Prosthetic Chest Wall Vascular Access


The most common sites and graft configurations for prosthetic arteriovenous access placement on the chest wall are axillary artery to ipsilateral axillary vein loop access and axillary artery to contralateral axillary vein straight or necklace access. An advantage of the looped graft configuration over the axillary-axillary straight or necklace access is that the contralateral axillary vessels are preserved as a site for future access placement. It is important that central venous patency be confirmed before surgery. If the proximal axillary, subclavian, or brachiocephalic vein has recently undergone angioplasty or stenting, an alternative site for arteriovenous access should be chosen, because recurrent stenosis after central venous intervention is common and influences patency. If there is a significant difference in blood pressure between the arms, the axillary artery on the side with the highest pressure is the preferred donor vessel. A preoperative contrast arteriogram or computed tomography angiogram should be considered. Access-related ischemia has not been reported, even when chest wall access was performed using vessels ipsilateral to an arm in patients with a prior history of steal syndrome. Chest wall prosthetic access may be associated with a lower risk of infection or wound complications than a lower extremity prosthetic arteriovenous access graft in a morbidly obese patient. A major disadvantage of chest wall access is that proximal control of the axillary vessels can be challenging if the graft becomes infected and excision required.


Transthoracic Cuffed Dialysis Catheter Placement


The procedure using a transthoracic cuffed dialysis catheter should be considered only after conventional central venous catheter placement is precluded by internal jugular and subclavian vein thrombosis. Severe cardiopulmonary disease is a relative contraindication to transthoracic cuffed dialysis catheter placement. The risk of bleeding is increased in patients with a short superior vena cava stump that requires cannulation of the vessel through the pericardial sac.


Hemodialysis Reliable Outflow Vascular Access Device Placement


Blood cultures should be obtained before Hemodialysis Reliable Outflow (HERO) device placement (Hemosphere, Minneapolis) and if present, bacteremia should be treated with appropriate antibiotics. If the silicone catheter component of the HERO device is inserted over a wire after removal of a tunneled dialysis catheter, the catheter tip should be cultured. Antibiotics should be considered if the culture is positive. Placement of the HERO device through a previously infected field should be avoided. If a tunneled dialysis catheter is present, the catheter should be removed as soon as the HERO device is ready for cannulation in 2 to 3 weeks and the tip should be cultured.




Operative Technique


Brachial Vein Transposition


There are important differences between brachial and basilic vein transpositions. Transposition of the brachial vein is technically more challenging because of its short length, greater depth, and numerous venous tributaries. Furthermore, although use of basilic vein transposition is well established, the role of brachial vein transposition is poorly defined. The largest experience consists of 58 brachial vein transpositions, most of which were completed in two stages. Primary and secondary patency rates were 52% and 92% at 12 months, respectively.


Anesthesia and Patient Positioning


Initial creation of an arteriovenous anastomosis is performed under local anesthesia. In the second stage, local sedation can be used in select cases of mobilization and transposition of the vein; however, a regional interscalene block or general anesthesia is preferred. For both stages, the patient is positioned at the table edge with the upper extremity abducted to 90 degrees and centered on an arm board.


Stage 1: Creation of the Arteriovenous Anastomosis


A longitudinal incision over the brachial pulse in the antecubital fossa exposes both the brachial artery and the brachial vein. Where multiple veins are present, the largest is used for the arteriovenous anastomosis. The vein is ligated distally and divided. The proximal vein is gently dilated hydrostatically with heparinized saline. Use of the most proximal radial artery, rather than the brachial artery, may reduce the risk of steal syndrome. An end-to-side vein to artery anastomosis is performed using a running 6-0 polypropylene suture ( Fig. 66-1 ).


Mar 13, 2019 | Posted by in VASCULAR SURGERY | Comments Off on Unconventional Venous Access Procedures for Chronic Hemodialysis
Premium Wordpress Themes by UFO Themes