Dialysis access interventions


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Presentation on Hemodialysis Access Evaluation and Intervention

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Dialysis access interventions

  1. 1. Arun Jagannathan MD Vascular & Interventional Radiology Central Illinois Radiological Associates
  2. 2. It’s all plumbing… www.radclinic.com
  3. 3. Introduction Arteriovenous graft or fistula Direct communication between artery and vein without an intervening capillary bed Etiology  Congenital  Acquired  Surgically created dialysis graft/fistula  Traumatically created  Iatrogenically created during cannulation/treatment of artery/vein www.radclinic.com
  4. 4. Traumatic AV Fistula www.radclinic.com
  5. 5. What is KDOQI? Kidney Disease Outcomes Quality Initiative Evidence-based clinical practice guidelines developed by volunteer physicians and health care providers for all stages of chronic kidney disease and related complications, from diagnosis to monitoring and management This presentation utilizes the National Kidney Foundation (NKF) KDOQI Clinical Practice Guidelines 2006 update www.kidney.org www.radclinic.com
  6. 6. AV Access for Dialysis Advent of hemodialysis in the early 60s has provided significantly improved longevity for CKD patients Initially used external AV shunt by Scribner and Quinton Currently provided by catheter, AV fistula, or AV graft Over 250k pts on permanent HD in US currently www.radclinic.com
  7. 7. HD Access Three primary methods Catheter  Non-tunneled  Tunneled AV Fistula AV Graft www.radclinic.com
  8. 8. www.radclinic.com
  9. 9. Catheter Access Advantages Immediate access Easy to place if central veins are patent Disadvantages Infection (greater w/ noncuffed/nontunneled) Potential Thrombosis/Occlusion Risks Flow rates limited www.radclinic.com
  10. 10. www.radclinic.com
  11. 11. Catheter Access Vein selection, order of preference Right Internal/External Jugular Vein Left Internal/External Jugular Vein Femoral veins (higher infection rates) IVC (tunneled translumbar or transhepatic) Subclavian (LAST RESORT as it may compromise future upper extremity fistula/graft creation) www.radclinic.com
  12. 12. Subclavian Occlusion www.radclinic.com
  13. 13. Nontunneled HD Catheter www.radclinic.com
  14. 14. Catheter Access Nontunneled (Mahurkar, etc.) SHORT term access (up to 10 days) Tunneled Cuffed Short to medium term access (weeks to months) Bridge to more durable access (AVF, AVG, PD) If a patient with acute onset renal failure is likely to require more than 7-10 days of access, primarily place a tunneled HD catheter www.radclinic.com
  15. 15. Tunneled Cuffed HD Catheter www.radclinic.com
  16. 16. Catheter Complications Treat when dialyzer blood flow of 300 cc/min not being attained in a catheter previously able to deliver greater than 350 at prepump pressure -250 torr Dysfunctional catheter (<300) for 2 treatments should be treated in HD unit w/ intraluminal interdialytic thrombolytic lock protocol between 2 treatments If the above fails, send for radiological evaluation www.radclinic.com
  17. 17. IR Evaluation of HD Catheter Catheter imaging w/ contrast can identify and treat various issues Residual lumen thrombus -> pharmacologic or mechanical thrombolysis Malpositioned catheter tip -> reposition or exchange Fibrin sheath at tip -> angioplasty/exchange/stripping SVC thrombosis/stenosis -> thrombolysis/angioplasty/stent www.radclinic.com
  18. 18. SVC Thrombosis www.radclinic.com
  19. 19. SVC Stenosis (tip malposition) www.radclinic.com
  20. 20. Fibrin Sheath www.radclinic.com
  21. 21. Catheter Infections Treatment Catheter exit-site, no tunnel infection  Treat w/ topical and/or oral Abx, not necessary to remove catheter  If bacteremic pt is afebrile w/in 48 hrs and stable, catheter salvage might be considered w/ interdialytic Abx lock solution and 3wks of parenteral Abx, f/u Blood Cx in 1 wk  Abx lock when f/u cultures indicate reinfection w/ same organism in pt w/ limited access  Short-term catheters should be removed when infected www.radclinic.com
  22. 22. Save the veins! CKD 3b or worse (eGFR < 45) pts are predialysis Veins of dorsum of hand preferred IV site Rotate sites if arm veins necessary PICC lines are NOT benign!  Incidence of central vein stenosis and occlusion after PICC/Port is 7%  Do NOT use PICC lines in predialysis patients (small bore central catheter via IJV for medium term access instead) www.radclinic.com
  23. 23. If at all possible… www.radclinic.com
  24. 24. www.radclinic.com
  25. 25. Surgical Access: AV Fistulas and Grafts Fistulas have a superior longevity compared to grafts (85% vs 50% patency at 2 yrs) but take longer to mature Up to 1/3 of fistulas fail to mature Fistulas can remain patient at flow rates of as low as 80 cc/min Grafts require flow rates of > 450 cc/min to prevent thrombosis www.radclinic.com
  26. 26. AV Fistula Creation Usually nondominant arm Radiocephalic or Brescia-Cimino is anastamosis of radial artery to cephalic vein Braciocephalic fistula is brachial artery to cephalic vein in the antecubital region Average of 4-6 wks for maturation Preferred sites radiocephalic > braciocephalic > transposed brachial basilic www.radclinic.com
  27. 27. AV Fistula Fistula Advantages  Lower infection rates  Higher blood flow rates  Lower thrombosis/stenosis rates Disadvantages  Longer maturation time  Potential for steal syndrome  Aneurysm formation www.radclinic.com
  28. 28. AV Fistula www.radclinic.com
  29. 29. AV Graft Creation Artificial vessel (graft) made of synthetic material such as PTFE or sterilized animal vessel connects the native artery to vein Preferred sites forearm loop > forearm straight > upper arm > chest wall > lower extremity www.radclinic.com
  30. 30. AV Graft Advantage Can be used much sooner Disadvantages Higher restenosis rates  usually at venous anastomosis Higher thrombosis rates Higher infection rates Potential steal Pseudoaneurysms www.radclinic.com
  31. 31. AV Graft www.radclinic.com
  32. 32. Dialysis Unit www.radclinic.com
  33. 33. Detection of Access Dysfunction Prospective surveillance of fistulae/grafts for hemodynamically significant stenosis, combined with correction of anatomic stenosis, improves patency rates and reduces incidence of thrombosis www.radclinic.com
  34. 34. Physical Examination Look (inspection) Aneurysms Fistula that does not collapse w/ arm elevation likely has outflow stenosis Palpable strictures Downstream stenosis can produce venous dilatation Arm edema Prolonged bleeding after needle withdrawal www.radclinic.com
  35. 35. www.radclinic.com
  36. 36. Physical Examination Touch (palpation) and listen (auscultate) Strong pulse is NOT evidence of good flow! Bruit over access system that is only systolic is abnormal, should be continuous Palpable thrill at the arterial, middle, and venous segments of graft predicts flow > 450 cc/min Palpable thrill at axilla predicts > 500 cc/min www.radclinic.com
  37. 37. Access Flow Number of techniques to measure www.radclinic.com
  38. 38. Access Flow www.radclinic.com
  39. 39. Access Pressures www.radclinic.com
  40. 40. www.radclinic.com
  41. 41. Recirculation Return of dialyzed blood to dialyzer without equilibration with systemic arterial circulation Not a recommended technique for assessing grafts Up to 1/3 of dysfunctional fistulae will show increased recirculation, but often occurs late www.radclinic.com
  42. 42. When to refer for evaluation Do not respond to a single isolated abnormal value, trend analysis is the key Flow rate < 600 in grafts and < 400-500 in fistulae Venous segment static pressure ratio greater than 0.5 in grafts or fistulae Arterial segment static pressure ratio greater than 0.75 in grafts Persistent abnormalities -> graftogram/fistulogram! www.radclinic.com
  43. 43. Treatment of Fistulae Complications Intervene for Inadequate flow Significant venous stenosis Aneurysm formation in primary fistula (also correct postaneurysmal stenosis) Ischemia www.radclinic.com
  44. 44. www.radclinic.com
  45. 45. Access Evaluation for Ischemia Patients prone to develop ischemia Elderly Hypertensive History of PAD Diabetes Not common (1-4%) but critical to recognize Most occur early, but up to a quarter develop months to years later www.radclinic.com
  46. 46. Access Evaluation for Ischemia Stage I, pale/blue and/or cold hand without pain Stage II, pain during exercise and/or HD Stage III, pain at rest Stage IV, ulcers/necrosis/gangrene www.radclinic.com
  47. 47. Stage IV www.radclinic.com
  48. 48. Ischemia -- Emergent Referral to Vascular Access Surgeon Treatments Angioplasty of arterial stenosis proximal to anastomosis Ligation of peripheral radial artery DRIL (distal revascularization—interval ligation)  Pts w/ venous anastomosis to brachial artery, anastomosis is bridged by venous bypass, after which the artery is ligated closely peripheral to the anastomosis Low flow rates and ischemia, proximal AV anastomosis technique with ligation of the previous anastomosis and placement of a new more proximal one with blood brought to the vein by an interposed vein graft or small caliber PTFE graft www.radclinic.com
  49. 49. Surgical Steal Tx DRIL – distal revascularization with interval ligation RUDI – revision using distal inflow www.radclinic.com
  50. 50. Infection Rare, but potentially lethal If at anastomosis, immediate surgery w/ resection More often at cannulation sites, rest and treat w/ Abx (treat like subacute bacterial endocarditis, 6 wks) www.radclinic.com
  51. 51. Graft Complications Extremity edema Persisting > 2 wks require contrast imaging to evaluate central veins with plasty as necessary  Stent placement if acute elastic recoil after plasty or if stenosis recurs within 3 months Indicators of risk for graft rupture (evaluate urgently) Poor eschar formation Spontaneous bleeding Rapid expansion of pseudoaneurysm Severe degeneration of graft material www.radclinic.com
  52. 52. Graft Complications Indications for revision/repair AVGs w/ severe degeneration or pseudoaneurysm (PSA) should be repaired if…  Number of cannulation sites limited by large or multiple PSAs  PSA threatens viability of overlying skin  PSA is symptomatic  Possible infection AVOID cannulation of PSA, especially if enlarging www.radclinic.com
  53. 53. Graft Complications Treat stenosis w/ angioplasty or surgery if > 50% in diameter and… Abnormal physical exam Decreasing intragraft flow (< 600) Elevated static pressure within graft www.radclinic.com
  54. 54. Take Home Points Save the veins! PICC lines and subclavian catheters are NOT benign, and should almost NEVER be used in dialysis or predialysis patients Surveillance of AV fistulae and grafts is crucial in order to intervene early and prevent loss of a potential access site Open line of communication between dialysis center, radiology, and surgical services is imperative www.radclinic.com
  55. 55. Infrascrotal Femoro-Femoral Perineal Bypass Graft Not to be wished upon your worst enemy! www.radclinic.com
  56. 56. The End www.radclinic.com