HEMODIALYSIS ACCESS KDOQI GUIDELINES

1. HEMODIALYSIS ACCESSKDOQI GUIDELINES ELEFTHERIOS XENOS, MD, PhD

2. Timing of referral to AV access surgeon and timing of placement of permanent vascular access • Patients with advanced CKD disease (late stage 4, stage 4 CKD (GFR <30), or based on progression of renal disease) who have elected hemodialysis as their choice of renal replacement therapy should be referred to an access surgeon in order to evaluate and plan construction of AV access • If at the conclusion of the evaluation, upper extremity arterial and venous anatomy is adequate for an autogenous AV access, such access should be constructed as soon as possible to allow it enough time to mature and undergo further interventions that may be needed to ensure that the access is ready to be used when dialysis is initiated. • If a prosthetic access is to be constructed, this should be delayed until just before the need for dialysis.

3. Technical remarks • The average maturation time of a new autogenous access is 2 to 4 months • Catheter use at initiation of dialysis is also associated with higher subsequent mortality • 81% of United States ESRD patients initiate dialysis with a catheter, and only 26% have an autogenous or prosthetic AV access already in place • Mortality is higher among patients who receive dialyses continuously through a catheter than among those who switch from a catheter to autogenous or prosthetic permanent access • Referral for initial vascular access placement should ideally occur approximately 6 months in advance of the anticipated need for dialysis

4. Preoperative evaluation • Factors associated with increased difficulty in establishing a functional AV access : diabetes mellitus, peripheral vascular disease, severe congestive heart failure, advanced age, and female gender • Ultrasound venous mapping is of critical importance in these patients, not only for identifying preferred autogenous access sites but also for evaluating the depth of venous structures • Studies have shown both 1.5 mm and 2.0 mm to be the minimally acceptable internal arterial diameters for successful autogenous AV access, although 2.0 mm seems to be the more commonly accepted limit in adults • The Allen's test confirms a patent palmar arch and is particularly important when an autogenous AV access at the wrist is planned. Bilateral extremity blood pressures should be recorded and found to be equal

6. Preoperative evaluation • Ultrasound imaging has become the common standard in preparation for an AV access procedure, ultrasound evaluation increased AV fistula construction from 14% to 63% • Ultrasound venous mapping, which is performed with and without a venous pressure tourniquet in place, evaluates vein diameter, patency, continuity, and distensibility of the planned venous outflow conduit. Both distensibility and venous diameter have been found to independently predict autogenous AV access success • Arteriography : individuals with suspected proximal arterial occlusive lesions where pre-AV access interventional procedures might both identify and treat the problem site, gaining adequate arterial inflow for the eventual autogenous AV access

7. Operative strategies to optimize the placement of autogenous arteriovenous accesses • Upper extremity access sites are used first, with the nondominant arm given preference over the dominant arm only when access opportunities are equal in both extremities • AV accesses are placed as far distally in the upper extremity as possible to preserve proximal sites for future accesses • When possible, autogenous AV accesses should be considered before prosthetic arteriovenous accesses are placed. These autogenous access configurations should include, in order of preference, the use of direct AV anastomosis, venous transpositions, and translocations • Lower extremity and body wall access sites are used only after all upper extremity access sites have been exhausted

8. Autogenous versus prosthetic vascular access for hemodialysis: A systematic review and meta-analysis M. Hassan Murad, MD, MPH, Mohamed B. Elamin, MBBS, Anton N. Sidawy, MD, MPH, German Malaga, MD, MSc, Adnan Z. Rizvi, MD, David N. Flynn, BS, Edward T. Casey, MD, Finnian R. McCausland, MD, Martina M. McGrath, MD, Danny H. Vo, MD, Ziad El-Zoghby, MD, Audra A. Duncan, MD, Michal J. Tracz, MD, Patricia J. Erwin, MLS and Victor M. Montori, MD, MSc Journal of Vascular Surgery Vol 48,page 34-47(November 2008)

13. 2.1 The order of preference for placement of fistulae in patients with kidney failure who choose HD as their initial mode of KRT should be (in descending order of preference): • 2.1.1 Preferred: Fistulae. (B) • 2.1.1.1 A wrist (radiocephalic) primary fistula. (A) • 2.1.1.2 An elbow (brachiocephalic) primary fistula. (A) • 2.1.1.3 A transposed brachial basilic vein fistula: (B) • 2.1.2 Acceptable: AVG of synthetic or biological material, such as: (B) • 2.1.2.1 A forearm loop graft, preferable to a straight configuration. • 2.1.2.2 Upper-arm graft. • 2.1.2.3 Chest wall or “necklace” prosthetic graft or lower-extremity fistula or graft; all upper-arm sites should be exhausted. • 2.1.3 Avoid if possible: Long-term catheters. (B) • 2.1.3.1 Short-term catheters should be used for acute dialysis and for a limited duration in hospitalized patients. Noncuffed femoral catheters should be used in bed-bound patients only. (B) • 2.1.3.2 Long-term catheters or dialysis port catheter systems should be used in conjunction with a plan for permanent access. Catheters capable of rapid flow rates are preferred. Catheter choice should be based on local experience, goals for use, and cost. (B) • 2.1.3.3 Long-term catheters should not be placed on the same side as a maturing AV access, if possible. (B)Special attention should be paid to consideration of avoiding femoral catheter access in HD patients who are current or future kidney transplant candidates.

14. Brescia-Cimino AVF

16. Choice of arteriovenous access when a patient is not a suitable candidate for forearm autogenous access • Two studies compared the autogenous upper arm access with a prosthetic lower arm access (prosthetic looped forearm access). • Placement of autogenous access in the upper arm is associated with a significantly lower rate of infections (RR, 0.23; 95% CI, 0.07-0.83) and nonsignificant trends for better 12-month primary (RR, 0.88; 95% CI, 0.72-1.07) and secondary (RR, 0.81; 95% CI, 0.54-1.20) patency. • Patency at 24 months was similar between the two accesses. Both studies reported the upper arm placement of autogenous access to be associated with fewer complications and to require fewer interventions to maintain patency.

19. Choice of arteriovenous access when a patient is not a suitable candidate for forearm autogenous access • For patients who have exhausted all forearm veins on both sides and, according to vein availability the surgeon should offer both alternatives to patients • Although the upper arm autogenous access may fare better compared with a forearm prosthetic access, using these two accesses sequentially may lead to additive benefit: This practice may help to preserve upper arm veins for future placement of autogenous access, may help to increase the caliber of these veins and maximize the success of future upper arm autogenous access, and may provide patients with an additional 1 to 3 years of functional hemodialysis access . • For patients at risk for ischemia, such as when the brachial or lower extremity arteries are used for inflow, a tapered graft should be considered for use with the smaller end of the graft placed at the arterial end

20. ACCESS CONFIGURATIONS Upper arm autogenous accesses • Autogenous brachial (or proximal radial)–cephalic upper arm direct access  • Autogenous brachial (or proximal radial)–basilic upper arm transposition  • Autogenous brachial (or proximal radial artery)–brachial vein upper arm transposition • Autogenous brachial (proximal radial) artery–axillary vein upper arm indirect greater saphenous translocation

23. ACCESS CONFIGURATIONS Configurations of prosthetic AV accesses • Prosthetic radial–antecubital forearm straight access  • Prosthetic brachial–antecubital forearm looped access • Prosthetic brachial–axillary (vein) upper arm access 

26. ACCESS CONFIGURATIONSConfigurations of prosthetic AV accesses • Prosthetic femoral artery–femoral vein lower extremity looped access  • Prosthetic axillary–axillary (vein) chest access (necklace prosthetic access)  • Prosthetic axillary–internal jugular chest loop access  • Prosthetic axillary–femoral (vein) body wall access 

30. The role of monitoring and surveillance in arteriovenous access management • “Monitoring” :physical examination indicators such as observation, palpation, and auscultation of the access, • “Surveillance” :tests to assess access function. • Clinical monitoring by skilled personnel was shown to have adequate diagnostic accuracy; clinical monitoring has been reported to have positive predictive value of 70% to 90% in prosthetic accesses and a specificity of 90% and a sensitivity of 93% in autogenous accesses • Lower incidence of thrombosis may translate into a reduction in access-related costs and hospitalizations • Flow surveillance produced a 32.5% reduction in the overall cost of access care

31. Surveillance of arteriovenous hemodialysis access: A systematic review and meta-analysis Edward T. Casey, DO, M. Hassan Murad, MD, MPH, Adnan Z. Rizvi, MD, Anton N. Sidawy, MD, MPH, Martina M. McGrath, MD, Mohamed B. Elamin, MBBS, David N. Flynn, BS, Finnian R. McCausland, MD, Danny H. Vo, MD, Ziad El-Zoghby, MD, Audra A. Duncan, MD, Michal J. Tracz, MD, Patricia J. Erwin, MLS and Victor M. Montori, MD, MSc Journal of Vascular Surgery Vol 48, 2008

33. The role of monitoring and surveillance in arteriovenous access management • We recommend regular clinical monitoring (inspection, palpation, auscultation, and monitoring for prolonged bleeding after needle withdrawal) to detect access dysfunction • We suggest access flow monitoring or static dialysis venous pressures for routine surveillance • We suggest performing a Duplex ultrasound (DU) study or contrast imaging study in accesses that display clinical signs of dysfunction or abnormal routine surveillance

34. The role of monitoring and surveillance in arteriovenous access management • Four most useful surveillance methods: (1) serial access flow measurement, (2) serial measurement of static dialysis venous pressure, (3) prepump arterial pressure, and (4) DU scanning • The KDOQI Guidelines recommend monthly measurement of access flow. It requires specialized equipment and a trained technician. • Access blood flow measurements. Access blood flow is the best determinant of access function. As an access develops progressive stenosis, access blood flow falls. Prosthetic access blood flow rate of <600 mL/min, or one that has decreased by >25% from the previous baseline, has a high predictive value for significant stenosis (87% to 100%).

35. The role of monitoring and surveillance in arteriovenous access management • Static venous dialysis pressure. The greatest value is in prosthetic accesses, but is of little or no value as a surveillance tool for autogenous. • Prepump arterial dialysis pressure: New autogenous accesses, which have a high incidence of failure to mature, almost always have an access flow problem that is on the arterial side of the venous needle and therefore will be identified by an excessively negative arterial dialysis pressure (ADP). In addition, most of the flow-restricting lesions in dysfunctional radial–cephalic as well as some other autogenous accesses, are likewise present on the arterial side of the venous needle and are often identified by increasingly negative ADPs. Therefore, routinely checking the ADP at every dialysis session is critically important in evaluating function in autogenous accesses, especially new ones. • Duplex ultrasound imaging. DU imaging can assess the access for both anatomic as well as flow abnormalities that may represent significant stenosis. This test requires measuring the peak systolic velocity (PSV) at the graft venous anastomosis and at any other area of visual stenosis. A ratio of PSV ≥2.0 at the stenotic site compared with the PSV immediately upstream is used to diagnose stenosis, with a positive predictive value of 80% for significant graft stenosis

36. The role of monitoring and surveillance in arteriovenous access management • Autogenous access :The best, most feasible tools for identifying dysfunction in autogenous access include (1) physical examination (monitoring), (2) routine measurement of prepump ADP at every dialysis session, and (3) serial access blood flow measurements • Prosthetic access function is best and most feasibly followed up by (1) a physical examination (monitoring), (2) serial access blood flow measurements, and (3) serial static VDP measurements.

37. Management of nonfunctional or failed arteriovenous access • An access that has failed to mature is patent but not functional • If the access is not adequately maturing by four weeks or not functional by 12 weeks (ie, access flow <500 ml/min, a recirculation higher than 10%, or inability to cannulate), a contrast study should be performed • Feasibility of salvage of the early nonmaturing autogenous accesses. Of 63 patients with inadequate autogenous access development, the access was patent in 74.7% after 1 year by using a systematic approach for revision that included diagnostic angiography, percutaneous angioplasty, and accessory vein ligation

38. Management of nonfunctional arteriovenous access • Access too deep  • Nonligated side branches  • Insufficient arterial inflow:Stenosis at the arterial anastomosis is the most common reason for inadequate arterial inflow. Arterial anastomotic stenosis usually occurs as a result of a technical error or neointimal hyperplasia. The next most common location for arterial stenosis is an orificial stenosis of the subclavian artery • Poor venous outflow :Poor venous outflow can also be caused by early anastomotic stenoses, which are technical errors, usually manifest as early thrombosis, but they can also lead to nonfunctionality or failure to mature in autogenous accesses.

39. Management of failed arteriovenous access • Prosthetic accesses have a much higher incidence of thrombosis and the access-specific stenotic lesion is more predictably found at the prosthetic venous anastomosis • In autogenous access the stenosis can be located anywhere along the access vein used for needle puncture, and multiple stenoses are often present(need for complete access evaluation) • Prosthetic and autogenous accesses can both have stenoses along the venous outflow tract, including central veins on the same side.

41. Management of nonfunctional or failed arteriovenous access • It is important to note that once access occlusion occurs, prolonged patency is unusual • In >90% of cases, prosthetic accesses failure is due to stenosis of the venous anastomosis, draining vein, or central vein • Histologic analysis of the venous anastomotic lesion demonstrates that it is identical to restenotic lesions that occur in the coronary arteries after coronary angioplasty or artery-to-artery bypass. The pathophysiology of prosthetic access failure is largely that of neointimal hyperplasia at the venous anastomosis.

42. Complications of arteriovenous hemodialysis access: Recognition and management • Dysfunctional hemostasis  • Infection  • Noninfectious fluid collections  • Pseudo aneurysm • Venous hypertension • Arterial steal syndrome  • High-output cardiac failure • Neuropathy

43. Dysfunctional hemostasis • Platelet dysfunction in uremia is common ,the hazard rate for bleeding in ESRD patients is 0.55 per annum, the hazard rate increased with antiplatelet therapy to 0.99 per annum • Management of acute bleeding is best treated with 1-deamino-8-d-arginine vasopressin (DDAVP). Cryoprecipitate may play an adjunctive role • Bleeding time in von Willebrand disease is often corrected during pregnancy, and randomized, placebo-controlled trials have confirmed that estrogen administration shortens the bleeding time in uremic patients, both women and men

44. Dysfunctional hemostasis • Evidence from randomized, prospective clinical trials shows no role for clopidogrel or warfarin as an adjunct to patency of prosthetic or autogenous AV access • Prosthetic access thrombosis was not reduced by 75 mg of clopidogrel plus 325 mg of acetylsalicylic acid • low dose warfarin (international normalized ratio, 1.4-1.9) reported no improvement in prosthetic graft function and an increase in major bleeding events with warfarin • Clopidogrel (75 mg) demonstrated no benefit for autogenous access

45. Venous hypertension • Flow in the radial artery increases from 30 to 300 mL/min after construction of a radiocephalic AV access, Mean flow using ultrasound-detected indicator dilution is 645 mL/min for radiocephalic and 1336 mL/min for brachiocephalic autogenous AV accesses. • The most frequent cause of upper extremity venous thrombosis is now central venous catheters or cardiac devices; the most powerful predictor is the presence of these devices, with an odds ratio of 7.3 • Approximately 50% of dialysis patients had a history of subclavian catheterization, and 50% of those exposed had stenoses that were considered significant • 10-year review of pacemaker insertions at one institution found a 71% incidence of significant subclavian vein stenosis; ligation of an ipsilateral AV access was required in 10 of 14 dialysis patients • defibrillator lead placements found 14 of 30 had >50% subclavian stenosis

47. Venous hypertension • Endovascular options offer a minimally invasive approach with relatively low risk • durability is only mediocre • repeated intervention is frequently necessary to maintain the result • Surgical management options include a direct approach to the site of obstruction, bypass of the obstruction, construction of the access in another extremity, and conversion to peritoneal dialysis.

48. Infection • An increasing international body of data implicates catheter access as the leading source of these bloodstream infections • 81% of United States ESRD patients initiate dialysis with a catheter, and only 26% have an autogenous or prosthetic AV access already in place • CDC, recruited 109 centers in 30 states to form the Dialysis Surveillance Network in the United States. Overall, there were 3.22 access-related infections per month, of which 1.78 per month were bacteremias. As expected, the rate ratios for access-related bacteremia were less with autogenous AV access (0.48 [95% CI, 0.35-0.65]), or prosthetic graft (1.0 [reference]) than with a cuffed catheter (9.2 [95% CI, 7.7-10.8]).

49. Infection • Staphylococcus spp constitute 32% to 53% • Enterococci and coagulase-negative Staphylococcus spp, 20% to 32 • Polymicrobial infections with gram-negative bacteria, 10% to 18 • Staphylococcus and Pseudomonas spp may both be highly destructive and likely to incur anastomotic disruption • 0.56% to 5% per year for autogenous AV access • 4% to 20% per year for prosthetic AV grafts