Alexis D. Jacob
Thomas S. Huber
Presentation
A 63-year-old female with a history of type II diabetes mellitus, hypertension, and chronic kidney disease (CKD) presents to the emergency room with shortness of breath and bilateral lower-extremity swelling. She states that she has not seen her primary care physician or nephrologist recently. She is hemodynamically stable but requires 2 L of oxygen by nasal cannula to maintain an oxygen saturation of >90%. Her physical examination is notable for bibasilar rales and pitting edema in both lower extremities. Her laboratory studies are remarkable for a blood urea nitrogen of 102 mg/dL, a serum creatinine 6.8 mg/dL, and a serum potassium of 6.1 mmol/L. An electrocardiogram demonstrates a normal sinus rhythm with slightly peaked T waves, and chest radiograph demonstrates findings consistent with fluid overload and congestive heart failure.
Diagnosis and Treatment
The patient appears to be in acute renal failure with the diagnosis based upon her generalized fluid overload, elevated blood urea nitrogen, and elevated potassium. She requires acute hemodialysis and needs dialysis access.
Discussion
The National Kidney Foundation Kidney Disease Outcome Quality Initiative (KDOQI) and the Fistula First Breakthrough Initiative (FFBI) have helped define the care of patients with CKD and end-stage renal disease (ESRD), emphasizing the role of autogenous hemodialysis access. These guidelines suggest that patients with stage 4 CKD (GFR < 30 mL/min) should be referred to an access surgeon for a permanent access well in advance of their anticipated dialysis initiation date. The guidelines recommend that autogenous arteriovenous access (AVF) should be constructed 6 months prior to initiation, while prosthetic access (AVG) should be constructed 3 to 6 weeks prior to initiation. Notably, the longer lead time for AVF allows for access maturation and any necessary remedial procedures. Additionally, patients with advanced CKD should be educated about the various options for renal replacement therapy (i.e., hemodialysis, peritoneal dialysis, transplantation) and engaged to preserve the veins on their nondominant arm for future access options. Despite national initiatives, the majority of patients in our country initiate dialysis with a catheter according to the United States Renal Data System. Although these dialysis catheters facilitate life-sustaining treatment, they are associated with a variety of complications including thrombosis, infection, and central vein stenosis/occlusion. The associated catheter patency rates are limited (i.e., primary patency rates 2 to 3 months), and the limited flow rates can lead to ineffective dialysis. Long-term catheter use is associated with increased mortality when compared to AVFs or AVGs, and the percentage of patients dialyzing through catheters is used as a marker of quality (or lack thereof) for the dialysis units. Noncuffed catheters are frequently placed in the urgent or emergent setting to facilitate the initiation of dialysis and should not be used for more than a week. Cuffed, tunneled catheters are more resistant to infection and can be used for time periods ranging from weeks to months. Both the noncuffed and the cuffed catheters should be inserted through the internal jugular vein opposite the side of the proposed permanent access. Notably, insertion of a dialysis catheter into the subclavian vein is associated with a significant risk of stenosis/occlusion that can preclude an ipsilateral permanent access.
Presentation Continued
A noncuffed hemodialysis catheter is placed in the emergency room and the patient is initiated on dialysis. The noncuffed catheter is replaced with a cuffed tunneled catheter after several dialysis sessions.
Diagnosis and Treatment
After the patient is “stabilized” on hemodialysis and her volume and electrolyte abnormalities are corrected, a permanent hemodialysis access should be constructed.
Discussion
As noted above, the KDOQI and the FFBI have emphasized the use of AVFs and have set ambitious national targets (AVF prevalence: KDOQI—65%, FFBI—66%). This strong emphasis on AVFs is based upon their improved patency rates (Figure 1), reduced complication rates, reduced mortality rate, and lower cost when compared with both cuffed tunneled catheters and AVGs. However, not all patients have suitable veins for an AVF and there are some disadvantages with AVFs that include an obligatory maturation period that can last several months (frequently mandating the use of a cuffed tunneled catheter as a “bridge”) and the need for remedial procedures to facilitate maturation. Although most providers would concede that a “mature” AVF is the optimal access, the ultimate goal should be a functional, durable permanent access rather than an AVF.
FIGURE 1 • The patency rates (percent patent) for the autogenous (Auto) and prosthetic (polytetrafluoroethylene [PTFE]) upper-extremity hemodialysis accesses are plotted against time (months) with the positive standard error bars. Both the primary (Auto 1, PTFE 1) and the secondary (Auto 2, PTFE 2) patency rates for the two access types are shown. The patency rates for the autogenous accesses were better than their corresponding prosthetic counterparts with the one exception of the initial (1.5 mos) time point for the primary patency comparison. (From Huber TS, et al. Patency of autogenous and PTFE upper extremity arteriovenous hemodialysis accesses: a systematic review. J Vasc Surg. 2003;38:1005–1011.)
The evaluation of patients presenting for permanent hemodialysis access includes a focused history and physical examination in combination with noninvasive imaging. Special attention should be directed at documenting the access history including procedures, revisions, and associated complications. Physical examination should include a detailed pulse examination with an Allen’s test to determine the forearm vessel responsible for the dominant arterial supply to the hand. The noninvasive testing in the diagnostic vascular laboratory includes examination of both the arterial and venous circulation. The arterial studies include blood pressure measurements of the brachial, radial, ulnar, and digital arteries along with the corresponding Doppler waveforms of all but the digital vessels (Figure 2). Additionally, Allen’s test is repeated and the diameters of both the radial and the brachial arteries are measured at the wrist and antecubital fossa, respectively. Venous imaging includes the interrogation of the cephalic and basilic veins from the wrist to the axilla complete with diameter measurements similar to the preoperative vein survey obtained prior to infrainguinal arterial revascularization (Figure 3).
FIGURE 2 • Part of the preoperative noninvasive arterial imaging studies are shown. The brachial, radial, and ulnar arterial pressures (mm Hg) are shown on the diagram of the upper extremities, while the finger pressures are shown in the center of the figure at the bottom. The corresponding Doppler waveforms (sec/div) are shown for the brachial, radial, and ulnar arteries. The FBI denotes the finger/brachial index and is the ratio of the finger pressure to the ipsilateral brachial artery pressure. Note the symmetric brachial artery pressures and the corresponding normal appearing triphasic Doppler waveforms.
FIGURE 3 • Part of the preoperative noninvasive venous imaging studies are shown. The diameters (mm) of both the basilic and cephalic veins are shown on the diagram of the upper extremities. The diameters are reported for the corresponding anatomic segment (prx upper—proximal upper arm, mid upper—mid upper arm, ac fossa—antecubital fossa, dista forea—distal forearm). Note that the basilic vein segments in both upper arms and the cephalic vein in the right upper arm are suitable for autogenous access using the diameter criteria (≥3 mm). The cephalic vein in the left upper arm was unable to be imaged. Additionally, the patient has a patent access in the right forearm that was not imaged.
An operative plan is then generated, based upon the results of the history/physical and noninvasive imaging with a strong emphasis on autogenous access. Our objective has been to select the combination of the artery and vein that would most likely result in a successful AVF. We have not felt constrained by the usual conventions of using the nondominant > dominant extremity and the forearm > arm although we have followed these standard approaches when the choices are equivocal. The criteria for an adequate artery and vein include an adequate diameter, no hemodynamically significant arterial inflow stenoses, no venous outflow stenoses, and a peripheral vein segment of suitable length and diameter (Table 1). Our preferences in descending order include the radiocephalic, radiobasilic, brachiocephalic, and brachiobasilic autogenous accesses prior to use of prosthetic material (Table 2). Notably, these preferences are consistent with the current KDOQI guidelines. Contrast arteriography and venography can be used to confirm the preliminary access choice although these are usually reserved for select patients with suspected arterial inflow or venous outflow lesions respectively.
TABLE 1. Criteria to Determine Suitability of Artery and Vein for Autogenous Access
aGreater than or equal to 15-mm Hg-pressure gradient between the brachial arteries for proposed arm accesses or between the ipsi lateral brachial and radial arteries for proposed forearm accesses.
TABLE 2. Hierarchy for Permanent Hemodialysis Accesses Configurations
Presentation Continued
The patient undergoes noninvasive imaging and is found to have a suitable basilic vein in the left upper arm for a possible AVF. Her brachial artery on the same side measures 3.5 mm at the antecubital fossa, and she has no evidence of arterial inflow stenosis based upon her Doppler waveforms and pressure measurements. Additionally, she has no evidence of venous outflow stenosis on either side.
Diagnosis and Treatment
Brachial-basilic AVF.
Surgical Approach
An incision is made in the upper arm over the basilic vein and this can be facilitated by having the course of the vein marked on the skin in the vascular laboratory during the preoperative evaluation. The basilic vein courses deep to the subcutaneous tissue and can actually be quite deep relative to the skin in obese patients. It courses adjacent to the medial antecubital cutaneous nerve in the distal upper arm and this nerve can actually serve as a landmark. The basilic vein should be dissected throughout its course and the branches ligated. We frequently suture-ligate the larger, broadbased branches with a 5-0 monofilament vascular suture. After the proximal end of the vein is transected (antecubital end), it is distended and all defects are repaired. The distended vein is then gently draped over the upper arm in an arc, and the future course of the transposed vein is marked on the skin. The brachial artery is dissected free in the distal upper arm at the site of the planned anastomosis. The brachial artery courses in the groove formed between the triceps and the biceps muscles beneath the deep fascia and lies deep to the median nerve, adjacent to the paired brachial veins and the ulnar nerve. Approximately a 3-cm segment of artery is dissected free to facilitate the anastomosis. A tunnel is then created along the course marked on the skin using a semicircular, hollow tunneling device. The tunneler is passed deep to the subcutaneous tissue near the antecubital fossa and the axilla, but immediately below the dermis throughout the region that will actually be used for cannulation. A sharp-tipped tunneler is particularly helpful because it facilitates passing the device in the correct plane. Patients are heparinized with 5,000 units after the tunnel is created and the anastomosis is performed in an end-side fashion with a running 6-0 monofilament suture. A closed suction drain (e.g., #10 Jackson-Pratt) is placed in the bed of the basilic vein harvest and brought out through a separate stab wound on the distal upper arm. The wound is closed in two layers with a 2-0 braided, absorbable suture and the skin is reapproximated with a subcuticular suture. It is important to examine the access (i.e., the thrill) during the closure to assure that it is has not been inadvertently narrowed or kinked.
Case Conclusion
The patient undergoes a left brachial-basilic AVF and is discharged home on her first postoperative day after removal of the closed suction drain. Follow-up to the vascular surgery clinic is arranged in 2 weeks.
Discussion
Patients are monitored throughout the postoperative period for the development of access-related ischemia or “steal.” Moderate or severe symptoms requiring intervention occur in approximately 10% of the brachial artery-based procedures. The diagnosis of access-related hand ischemia is a clinical one that can be corroborated with noninvasive testing for equivocal cases. Preoperative predictors include advanced age, female gender, the presence of peripheral vascular occlusive disease, large conduits, and a prior episode of hand ischemia. Treatment options include access ligation, distal revascularization and interval ligation (DRIL), proximalization of the anastomosis, and limiting the flow through the access (e.g., “banding”).
Patients are seen in the outpatient clinic 2 weeks after their operative procedure and at monthly intervals thereafter until their accesses are usable for dialysis. The KDOQI recommendations (“rule of 6’s”—6 mm in diameter, 6 mm depth below the skin, 600 mL/min) are used to determine when the access is suitable for cannulation. Accesses that fail to dilate and those without a thrill are investigated with a catheter-based fistulagram to identify potential problems. Open surgical or endovascular procedures (e.g., balloon angioplasty, vein patch angioplasty) are performed as necessary based upon the fistulagram. When the accesses are ultimately deemed suitable for cannulation, the patients are provided with a diagram of their specific access configuration and instructions for cannulation while a similar facsimile is sent to their dialysis unit. The cuffed, tunneled catheter is removed when the AVF can be cannulated repeatedly.
TAKE HOME POINTS
· Patients with stage IV and V CKD should be referred to an access surgeon well in advance of their anticipated hemodialysis initiation date.
· Cuffed tunneled catheters should be inserted into the internal jugular vein contralateral to the site of the planned permanent access.
· A mature autogenous arteriovenous hemodialysis access is the best access option, but the primary goal is a durable, functional permanent access.
· Preoperative arterial and venous noninvasive imaging can help identify the optimal artery and vein combination for a permanent access.
· Patients should be followed in the surgical clinic until the access is suitable for cannulation and monitored closely for access-related hand ischemia.
· The construction and maintenance of hemodialysis access is a challenging problem that requires a lifetime plan and committed providers.
SUGGESTED READINGS
Fistula First Breakthrough Initiative: http://fistulafirst.org.
Huber TS, Carter JW, Carter RL, et al. Patency of autogenous and PTFE upper extremity arteriovenous hemodialysis accesses: A systematic review. J Vasc Surg. 2003;38:1005–1511.
Huber TS, Ozaki CK, Flynn TC, et al. Prospective validation of an algorithm to maximize native arteriovenous fistulae for chronic hemodialysis access. J Vasc Surg. 2002;36:452–459.
National Kidney Foundations KDOQI 2006 Vascular Access Guidelines. Am J Kidney Dis. 2006;48:S177–S322.
U.S. Renal Data System. USRDS 2010 Annual Data Report: Atlas of Chronic Kidney Disease and End-Stage Renal Disease in the United States, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 2010.