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The complications of AV access for H/D ©2007 UpToDate ®  The 2006 NKF/Dialysis Outcomes Quality Initiative (K/DOQI) guidel...
Chronic hemodialysis vascular access:  Types and placement <ul><li>AV fistulas  </li></ul><ul><li>Synthetic grafts  </li><...
AV   fistulas <ul><li>End-to-side vein-to-artery anastomosis </li></ul><ul><li>The 2005 Canadian and 2006 United States K/...
Synthetic grafts <ul><li>Polytetrafluoroethylene (PTFE, also known as Gortex)  </li></ul><ul><li>Straight or looped and ra...
Tunneled cuffed catheters  <ul><li>Internal jugular vein  </li></ul><ul><li>Right sided catheters malfunction less than le...
COMPARISON  <ul><li>Primary failure: </li></ul><ul><ul><li>an access that never provided reliable hemodialysis  </li></ul>...
Nonthrombotic complications <ul><li>Infection </li></ul><ul><li>Heart failure </li></ul><ul><li>Distal ischemia </li></ul>...
Infection <ul><li>Accounts for 20% of access loss  </li></ul><ul><li>The source of most bacteremia in H/D p’t </li></ul><u...
<ul><li>Prophylaxis? </li></ul><ul><ul><li>unsuccessful in preventing  </li></ul></ul><ul><li>The 2006 NKF/Dialysis Outcom...
Heart failure <ul><li>Rare, even in p’t with cardiac disease  </li></ul><ul><li>Fistula increase LV hypertrophy </li></ul>...
Distal ischemia <ul><li>Distal hypoperfusion of the extremity </li></ul><ul><li>Shunting (&quot;steal&quot;) of arterial b...
Aneurysm and pseudoaneurysm <ul><li>Infrequent complications </li></ul><ul><li>Repeated cannulation in the same area  </li...
Venous hypertension <ul><li>Valvular incompetence or central venous stenosis </li></ul><ul><li>S/S: </li></ul><ul><ul><li>...
Median nerve injury <ul><li>Carpal tunnel syndrome  </li></ul><ul><li>Local amyloid deposition </li></ul><ul><li>Compressi...
Seroma formation <ul><li>Weeping syndrome: </li></ul><ul><ul><li>ultrafiltration of plasma across a PTFE graft </li></ul><...
Thrombotic complications
Introduction <ul><li>The most common (80-85%) complication of permanent vascular access  </li></ul><ul><li>The cumulative ...
Pathogenesis  <ul><li>Initiated by endothelial cell injury  </li></ul><ul><li>Up-regulation of adhesion molecules on the e...
PROSPECTIVE MONITORING K/DOQI guidelines for surveillance of grafts : <ul><li>Intra-access flow: </li></ul><ul><ul><li>dup...
PROSPECTIVE MONITORING K/DOQI guidelines for surveillance of fistulas : <ul><li>Direct flow measurements  </li></ul><ul><l...
When to refer? <ul><li>More than one abnormalities  </li></ul><ul><li>Persistent abnormalities  </li></ul><ul><li>Access f...
Treatment of venous stenosis <ul><li>Percutaneous angioplasty </li></ul><ul><li>Endovascular metallic stents </li></ul><ul...
Percutaneous angioplasty <ul><li>Corrects over 80% of stenosis  </li></ul><ul><ul><li>in both native fistulas and syntheti...
<ul><li>Success with angioplasty varies with the size of the stenosis  </li></ul><ul><li>Monitoring:  </li></ul><ul><ul><l...
Endovascular metallic stents <ul><li>Advocated as a method of preventing recurrent stenosis after angioplasty  </li></ul><...
Surgical revision <ul><li>The gold standard  </li></ul><ul><li>The lowest recurrence rate  </li></ul><ul><li>Generally bee...
STRATEGIES TO PREVENT THROMBOSIS  <ul><li>Antiplatelet agents </li></ul><ul><li>Systemic anticoagulation </li></ul><ul><li...
Antiplatelet agents <ul><li>Dipyridamole, low-dose aspirin w/ or w/o sulfinpyrazone, aspirin + clopidogrel </li></ul><ul><...
<ul><li>A surprising finding:  </li></ul><ul><ul><li>apparent increase in thrombosis with aspirin </li></ul></ul><ul><ul><...
Systemic anticoagulation <ul><li>A paucity of data exists </li></ul><ul><li>A multicenter prospective study: </li></ul><ul...
Antiphospholipid antibodies <ul><li>Lupus anticoagulant and anticardiolipin antibodies  </li></ul><ul><li>Increased incide...
Fish oil <ul><li>Omega-3 fatty acids  </li></ul><ul><li>Inhibit cyclooxygenase, may dampen intimal hyperplasia in vein gra...
Other preventive therapies <ul><li>Endovascular radiation </li></ul><ul><ul><li>prevention of vascular access stenosis  </...
TREATMENT OF THROMBOSES The 2006 K/DOQI guidelines <ul><li>With grafts and associated stenosis:  </li></ul><ul><ul><li>Sur...
Surgical thrombectomy <ul><li>Outpatient procedure </li></ul><ul><ul><li>quick </li></ul></ul><ul><ul><li>very low complic...
Thrombolysis <ul><li>Attempts to fistula thrombosis with urokinase and streptokinase, originally yielded disappointing res...
Mechanical disruption <ul><li>A study showed: </li></ul><ul><ul><li>Similar rate of success with surgical thrombectomy and...
K/DOQI goals for treatment <ul><li>A success rate of 85%: </li></ul><ul><ul><li>defined by the ability to use the graft at...
Summary <ul><li>Nonthrombotic complications: </li></ul><ul><ul><li>Infection: 20% </li></ul></ul><ul><ul><li>Heart failure...
Thanks for your attention!! References: 2007 UpToDate  The 2006 NKF/Dialysis Outcomes Quality Initiative (K/DOQI) guidelin...
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  1. 1. The complications of AV access for H/D ©2007 UpToDate ® The 2006 NKF/Dialysis Outcomes Quality Initiative (K/DOQI) guidelines The 2006 Canadian Society of Nephrology hemodialysis guidelines 2007-04-09 Ri 陳昱潤
  2. 2. Chronic hemodialysis vascular access: Types and placement <ul><li>AV fistulas </li></ul><ul><li>Synthetic grafts </li></ul><ul><li>Tunneled cuffed catheters </li></ul>
  3. 3. AV fistulas <ul><li>End-to-side vein-to-artery anastomosis </li></ul><ul><li>The 2005 Canadian and 2006 United States K/DOQI guidelines: </li></ul><ul><ul><li>radiocephalic </li></ul></ul><ul><ul><li>brachiocephalic </li></ul></ul><ul><ul><li>brachiobasilic </li></ul></ul><ul><ul><li>Brachial artery and median antecubital vein </li></ul></ul>
  4. 4. Synthetic grafts <ul><li>Polytetrafluoroethylene (PTFE, also known as Gortex) </li></ul><ul><li>Straight or looped and ranges between 4 to 8 mm in diameter </li></ul><ul><li>Straight forearm (radial artery to cephalic vein) </li></ul><ul><li>Looped forearm (brachial artery to cephalic vein) </li></ul><ul><li>Straight upper arm (brachial artery to axillary vein) </li></ul><ul><li>Looped upper arm (axillary artery to axillary vein) </li></ul><ul><li>The 2006 K/DOQI work group prefers a forearm loop graft </li></ul>
  5. 5. Tunneled cuffed catheters <ul><li>Internal jugular vein </li></ul><ul><li>Right sided catheters malfunction less than left sided </li></ul><ul><li>Subclavian catheters should be avoided to prevent subclavian stenosis </li></ul>
  6. 6. COMPARISON <ul><li>Primary failure: </li></ul><ul><ul><li>an access that never provided reliable hemodialysis </li></ul></ul><ul><ul><li>fistula > graft </li></ul></ul><ul><li>Secondary failure: </li></ul><ul><ul><li>graft > fistula </li></ul></ul><ul><li>Time to use: </li></ul><ul><ul><li>fistula: weeks to 6 months </li></ul></ul><ul><ul><li>graft: days to weeks </li></ul></ul><ul><ul><li>catheter: intermediate-duration </li></ul></ul><ul><li>Recommendation: </li></ul><ul><ul><li>fistula preferred </li></ul></ul>
  7. 7. Nonthrombotic complications <ul><li>Infection </li></ul><ul><li>Heart failure </li></ul><ul><li>Distal ischemia </li></ul><ul><li>Aneurysm and pseudoaneurysm </li></ul><ul><li>Venous hypertension </li></ul><ul><li>Median nerve injury </li></ul><ul><li>Seroma formation </li></ul>
  8. 8. Infection <ul><li>Accounts for 20% of access loss </li></ul><ul><li>The source of most bacteremia in H/D p’t </li></ul><ul><li>S. aureus, S. epidermidis </li></ul><ul><li>Predisposing factors: </li></ul><ul><ul><li>pseudoaneurysms or perifistular hematomas </li></ul></ul><ul><ul><li>severe pruritus over needle sites </li></ul></ul><ul><ul><li>intravenous drug abuse </li></ul></ul><ul><ul><li>secondary surgical procedures </li></ul></ul>
  9. 9. <ul><li>Prophylaxis? </li></ul><ul><ul><li>unsuccessful in preventing </li></ul></ul><ul><li>The 2006 NKF/Dialysis Outcomes Quality Initiative (K/DOQI) guidelines: </li></ul><ul><ul><li>six weeks Abx for fistula </li></ul></ul><ul><ul><li>surgical excision with septic emboli </li></ul></ul><ul><ul><li>infected PTFE grafts: </li></ul></ul><ul><ul><ul><li>surgical intervention, may require skin flaps, 3 weeks of Abx </li></ul></ul></ul>
  10. 10. Heart failure <ul><li>Rare, even in p’t with cardiac disease </li></ul><ul><li>Fistula increase LV hypertrophy </li></ul><ul><li>High-output heart failure if fistula flow >20% C.O </li></ul><ul><li>Treatment: </li></ul><ul><ul><li>limiting fistula flow by banding </li></ul></ul><ul><ul><li>access thrombosis, may not permanently decrease flow </li></ul></ul><ul><ul><li>peritoneal dialysis or cuffed catheter </li></ul></ul>
  11. 11. Distal ischemia <ul><li>Distal hypoperfusion of the extremity </li></ul><ul><li>Shunting (&quot;steal&quot;) of arterial blood flow </li></ul><ul><li>1-20%, DM and the elderly </li></ul><ul><li>Absent pulse or a cold extremity warrant immediate surgery </li></ul><ul><li>Paresthesia, sense of coolness with retained pulses, improve over weeks </li></ul><ul><li>Management: </li></ul><ul><ul><li>percutaneous transluminal balloon angioplasty </li></ul></ul><ul><ul><li>distal revascularization with interval ligation </li></ul></ul>
  12. 12. Aneurysm and pseudoaneurysm <ul><li>Infrequent complications </li></ul><ul><li>Repeated cannulation in the same area </li></ul><ul><li>Pseudoaneurysm: </li></ul><ul><ul><li>a particular problem with PTFE grafts, the material deteriorates after prolonged use </li></ul></ul><ul><li>If small defect (<5 mm), occlude it! </li></ul><ul><li>Options for the evaluation: graft rupture </li></ul><ul><ul><li>spontaneous bleeding, rapid expansion in size, severe degeneration in the material </li></ul></ul><ul><li>The K/DOQI guidelines for intervention: </li></ul><ul><ul><li>The skin overlying the fistula is compromised </li></ul></ul><ul><ul><li>a risk of fistula rupture </li></ul></ul><ul><ul><li>Available puncture sites are limited </li></ul></ul>
  13. 13. Venous hypertension <ul><li>Valvular incompetence or central venous stenosis </li></ul><ul><li>S/S: </li></ul><ul><ul><li>severe upper limb edema </li></ul></ul><ul><ul><li>skin discoloration </li></ul></ul><ul><ul><li>access dysfunction </li></ul></ul><ul><ul><li>peripheral ischemia with resultant fingertip ulceration </li></ul></ul><ul><li>Venous duplex ultrasound, venography </li></ul><ul><li>Treatment: </li></ul><ul><ul><li>correcting the underlying vascular problem </li></ul></ul><ul><ul><li>screening </li></ul></ul>
  14. 14. Median nerve injury <ul><li>Carpal tunnel syndrome </li></ul><ul><li>Local amyloid deposition </li></ul><ul><li>Compression of the median nerve </li></ul><ul><ul><li>due to the extravasation of blood or fluid </li></ul></ul><ul><li>Ischemic injury by a vascular steal effect </li></ul>
  15. 15. Seroma formation <ul><li>Weeping syndrome: </li></ul><ul><ul><li>ultrafiltration of plasma across a PTFE graft </li></ul></ul><ul><li>A pocket of serous fluid, firm and gelatinous </li></ul><ul><li>Typically at the arterial end of the graft where intraluminal pressure is higher </li></ul><ul><li>Occur at the distal end if there is significant central venous obstruction </li></ul><ul><li>Fistulogram to exclude central venous stenosis </li></ul>
  16. 16. Thrombotic complications
  17. 17. Introduction <ul><li>The most common (80-85%) complication of permanent vascular access </li></ul><ul><li>The cumulative fistula patency rate in most centers: </li></ul><ul><ul><li>60 to 70% at one year </li></ul></ul><ul><ul><li>50 to 60% at two years </li></ul></ul><ul><li>Expensive to maintain fistula patency, 15% of annual spending </li></ul><ul><li>Predisposing factor: </li></ul><ul><ul><li>anatomic venous stenosis, 80-85% </li></ul></ul><ul><ul><li>arterial stenosis </li></ul></ul><ul><ul><li>excessive post-dialysis fistula compression </li></ul></ul><ul><ul><li>hypotension </li></ul></ul><ul><ul><li>increased hematocrit levels </li></ul></ul><ul><ul><li>hypovolemia </li></ul></ul><ul><ul><li>hypercoagulable states </li></ul></ul><ul><li>A standard definition for stenosis does not exist </li></ul><ul><li>Narrowing >= 50% </li></ul>
  18. 18. Pathogenesis <ul><li>Initiated by endothelial cell injury </li></ul><ul><li>Up-regulation of adhesion molecules on the endothelial cell surface </li></ul><ul><li>leukocyte adherence to damaged and activated endothelium causes the release of chemotactic and mitogenic factors for vascular smooth muscle cells </li></ul><ul><li>Enhancing smooth muscle cell migration and proliferation </li></ul><ul><li>Activated PLT and inflammatory cells: </li></ul><ul><ul><li>secrete oxidants and toxins, injure the vessel wall </li></ul></ul>
  19. 19. PROSPECTIVE MONITORING K/DOQI guidelines for surveillance of grafts : <ul><li>Intra-access flow: </li></ul><ul><ul><li>duplex and variable flow Doppler ultrasound </li></ul></ul><ul><ul><li>magnetic resonance angiography </li></ul></ul><ul><ul><li>dilution based upon ultrasound, urea, or thermal techniques </li></ul></ul><ul><li>Static venous pressure </li></ul><ul><li>Duplex ultrasonography </li></ul><ul><li>Gadolinium-based MRI should be avoided due to nephrogenic systemic fibrosis </li></ul>
  20. 20. PROSPECTIVE MONITORING K/DOQI guidelines for surveillance of fistulas : <ul><li>Direct flow measurements </li></ul><ul><li>Physical findings suggestive of stenosis: </li></ul><ul><ul><li>arm swelling </li></ul></ul><ul><ul><li>prolonged bleeding after needle withdrawal </li></ul></ul><ul><ul><li>collateral veins </li></ul></ul><ul><ul><li>altered features of the pulse or thrill </li></ul></ul><ul><li>Duplex ultrasonography </li></ul><ul><li>Static pressure </li></ul>
  21. 21. When to refer? <ul><li>More than one abnormalities </li></ul><ul><li>Persistent abnormalities </li></ul><ul><li>Access flow rate <600 mL/min for fistula </li></ul><ul><li>Access flow rate <400-500 mL/min for graft </li></ul><ul><li>Venous segment static pressure ratio >0.5 </li></ul><ul><li>Arterial segment static pressure ratio >0.75 </li></ul>
  22. 22. Treatment of venous stenosis <ul><li>Percutaneous angioplasty </li></ul><ul><li>Endovascular metallic stents </li></ul><ul><li>Surgical revision </li></ul>
  23. 23. Percutaneous angioplasty <ul><li>Corrects over 80% of stenosis </li></ul><ul><ul><li>in both native fistulas and synthetic grafts </li></ul></ul><ul><ul><li>in both venous and arterial outflow tracts </li></ul></ul><ul><li>The 2006 K/DOQI guidelines recommend angioplasty if: </li></ul><ul><ul><li>stenosis in fistula >50% </li></ul></ul><ul><ul><li>stenosis in graft >50% + (abnormal physical findings, intragraft blood flow <600, or elevated static pressure) </li></ul></ul>
  24. 24. <ul><li>Success with angioplasty varies with the size of the stenosis </li></ul><ul><li>Monitoring: </li></ul><ul><ul><li>high recurrence rate (55 to 70% at 12 months) </li></ul></ul><ul><li>Recurrent lesions: repeat angioplasty </li></ul><ul><li>Summary: </li></ul><ul><ul><li>Reduced vascular morbidity </li></ul></ul><ul><ul><li>Preserves future access sites </li></ul></ul>
  25. 25. Endovascular metallic stents <ul><li>Advocated as a method of preventing recurrent stenosis after angioplasty </li></ul><ul><li>Variable results </li></ul>
  26. 26. Surgical revision <ul><li>The gold standard </li></ul><ul><li>The lowest recurrence rate </li></ul><ul><li>Generally been replaced by angioplasty: </li></ul><ul><ul><li>requiring hospitalization </li></ul></ul><ul><ul><li>extending the fistula site further up the involved extremity </li></ul></ul>
  27. 27. STRATEGIES TO PREVENT THROMBOSIS <ul><li>Antiplatelet agents </li></ul><ul><li>Systemic anticoagulation </li></ul><ul><li>Antiphospholipid antibodies </li></ul><ul><li>Fish oil </li></ul><ul><li>Other preventive therapies </li></ul>
  28. 28. Antiplatelet agents <ul><li>Dipyridamole, low-dose aspirin w/ or w/o sulfinpyrazone, aspirin + clopidogrel </li></ul><ul><li>Neither therapy appeared to be effective, the recurrence rate was 78% </li></ul><ul><li>In patients with new grafts , the rate of thrombosis was reduced by dipyridamole (relative risk 0.35 versus placebo). </li></ul>
  29. 29. <ul><li>A surprising finding: </li></ul><ul><ul><li>apparent increase in thrombosis with aspirin </li></ul></ul><ul><ul><li>one possibility: cyclooxygenase inhibition shifts arachidonate metabolism toward nonprostaglandin metabolites (such as lipoxygenases), promote intimal hyperplasia </li></ul></ul><ul><li>The role of anti-PLT agents in preventing fistula thrombosis is unresolved </li></ul>
  30. 30. Systemic anticoagulation <ul><li>A paucity of data exists </li></ul><ul><li>A multicenter prospective study: </li></ul><ul><ul><li>warfarin to patients with newly placed PTFE grafts </li></ul></ul><ul><ul><li>no increasing graft survival </li></ul></ul><ul><ul><li>with significant bleeding </li></ul></ul><ul><li>We only administer warfarin to p’t with repetitive thrombus but w/o anatomic stenosis </li></ul>
  31. 31. Antiphospholipid antibodies <ul><li>Lupus anticoagulant and anticardiolipin antibodies </li></ul><ul><li>Increased incidence of thromboses </li></ul><ul><li>Increase the risk of access thrombosis </li></ul><ul><ul><li>A report of 97 patients on hemodialysis </li></ul></ul><ul><ul><li>62% versus 26% </li></ul></ul><ul><li>Reasonable to screen: </li></ul><ul><ul><li>Warfarin is indicated in patients with thromboses not involving the access </li></ul></ul>
  32. 32. Fish oil <ul><li>Omega-3 fatty acids </li></ul><ul><li>Inhibit cyclooxygenase, may dampen intimal hyperplasia in vein grafts </li></ul><ul><li>Among 24 patients with PTFE grafts: </li></ul><ul><ul><li>At 12 months, the primary patency rate was significantly higher: 77% versus 15% </li></ul></ul>
  33. 33. Other preventive therapies <ul><li>Endovascular radiation </li></ul><ul><ul><li>prevention of vascular access stenosis </li></ul></ul><ul><ul><li>gamma radiation: effective in animal models in inhibiting intimal hyperplasia </li></ul></ul><ul><ul><li>catheter-based irradiation: utilized to prevent restenosis after angioplasty in the coronary circulation </li></ul></ul><ul><ul><li>primary patency at 6 months was better: 42% versus 0 </li></ul></ul><ul><ul><li>no difference in secondary patency at 6 (92% versus 91%) or 12 months (44% versus 57%). </li></ul></ul><ul><li>Gene therapy </li></ul><ul><ul><li>theoretically effective, result in less systemic toxicity </li></ul></ul>
  34. 34. TREATMENT OF THROMBOSES The 2006 K/DOQI guidelines <ul><li>With grafts and associated stenosis: </li></ul><ul><ul><li>Surgical thrombectomy </li></ul></ul><ul><ul><li>Thrombolysis </li></ul></ul><ul><ul><li>Mechanical disruption </li></ul></ul><ul><li>With fistulas: </li></ul><ul><ul><li>no recommend any approach to the removal of thromboses </li></ul></ul>
  35. 35. Surgical thrombectomy <ul><li>Outpatient procedure </li></ul><ul><ul><li>quick </li></ul></ul><ul><ul><li>very low complication rate </li></ul></ul><ul><ul><li>initially success in 90% </li></ul></ul><ul><li>However, failure to correct the underlying outflow stenosis leads to rapid rethrombosis </li></ul>
  36. 36. Thrombolysis <ul><li>Attempts to fistula thrombosis with urokinase and streptokinase, originally yielded disappointing results </li></ul><ul><li>Dosing adjustments and technical advances: </li></ul><ul><ul><li>improved the success rate </li></ul></ul><ul><ul><li>reduced the incidence of bleeding </li></ul></ul><ul><li>Combines thrombolytic therapy with mechanical clot disruption: </li></ul><ul><ul><li>90% patency </li></ul></ul><ul><ul><li>50% patency in 1 year </li></ul></ul>
  37. 37. Mechanical disruption <ul><li>A study showed: </li></ul><ul><ul><li>Similar rate of success with surgical thrombectomy and urokinase </li></ul></ul><ul><ul><li>considerably greater long-term patency </li></ul></ul><ul><li>The major concern: pulmonary emboli </li></ul><ul><ul><li>only 1 of 650 had pulmonary embolus </li></ul></ul><ul><ul><li>2 of 650 developed transient chest pain of undetermined etiology </li></ul></ul>
  38. 38. K/DOQI goals for treatment <ul><li>A success rate of 85%: </li></ul><ul><ul><li>defined by the ability to use the graft at least once post-procedure </li></ul></ul><ul><li>After percutaneous thrombectomy </li></ul><ul><ul><li>40% patency at 3 months </li></ul></ul><ul><li>After surgical thrombectomy </li></ul><ul><ul><li>50% patency at 6 months </li></ul></ul><ul><ul><li>40% patency at 12 months </li></ul></ul>
  39. 39. Summary <ul><li>Nonthrombotic complications: </li></ul><ul><ul><li>Infection: 20% </li></ul></ul><ul><ul><li>Heart failure </li></ul></ul><ul><ul><li>Distal ischemia </li></ul></ul><ul><ul><li>Aneurysm and pseudoaneurysm </li></ul></ul><ul><ul><li>Venous hypertension </li></ul></ul><ul><ul><li>Median nerve injury </li></ul></ul><ul><ul><li>Seroma formation </li></ul></ul><ul><li>Thrombotic complication: 80-85% </li></ul>
  40. 40. Thanks for your attention!! References: 2007 UpToDate The 2006 NKF/Dialysis Outcomes Quality Initiative (K/DOQI) guidelines The 2006 Canadian Society of Nephrology hemodialysis guidelines
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