NKF KDOQI GUIDELINES 2000
GUIDELINES FOR VASCULAR ACCESS
V. Management of Complications: Optimal Approaches for Treating Complications
Management of vascular access complications relies on a multidisciplinary approach involving nephrologists, nephrology nurses, vascular interventionists, and surgeons. The goal of these management efforts is the preservation of vascular access.
Treatment of Stenosis Without Thrombosis in Dialysis AV Grafts and Primary AV Fistulae
A. Stenoses that occur in a dialysis AV graft or primary AV fistula (venous outflow or arterial inflow) should be treated with percutaneous transluminal angioplasty or surgical revision if the stenosis is >50% of the lumen diameter and is associated with the following clinical/physiologic abnormalities: (Evidence)
1. Previous thrombosis in the access
2. Elevated venous dialysis pressure
3. Abnormal urea or other recirculation measurements
4. Abnormal physical findings
5. Unexplained decrease in measurement of dialysis dose
6. Decreasing access flow (see Guideline 17: When to Intervene Dialysis AV Grafts for Venous Stenosis, Infection, Graft Degeneration, and Pseudoaneurysm Formation, and Guideline 18: When to Intervene Primary AV Fistulae)
B. Each dialysis center should determine which procedure (angioplasty versus surgical revision) is best for the patient based on the expertise at that center. (Evidence/Opinion)
C. Stenosis, as well as the clinical parameters used to detect it, should return to within acceptable limits following intervention. (Evidence)
Stenosis Treatment Outcomes:
A. Centers should monitor stenosis treatment outcomes on the basis of patency; reasonable patency goals (for the center as a whole) for PTA and surgical revision in the absence of thrombosis are:
PTA 50% unassisted patency* at 6 months (Evidence); no more than 30% residual stenosis postprocedure and resolution of physical indicator(s) of stenosis
Surgical revision 50% unassisted patency at 1 year (Opinion)
B. If angioplasty is required more than 2 times within 3 months, the patient should be referred for surgical revision if such an option is available and if the patient is a good surgical candidate. (Opinion)
C. Stents are useful in selected instances (eg, limited residual access sites, surgically inaccessible lesions, contraindication to surgery) when PTA fails. (Evidence)
Rationale Correction of venous stenoses of >50% lumen diameter associated with a clinical/physiologic variable correlates with a significant decrease in the rate of fistula thrombosis and an improvement in access patency.9,103,109,119 Eighty-five percent to 90% of AV access thromboses are associated with venous outflow stenotic lesions caused by endothelial and fibromuscular hyperplasia.13,66,103,119,125 Few studies comparing venous stenoses correction with PTA versus surgical revision have been performed, and they report conflicting results.172,173 Published noncomparative data do not indicate a preferred technique for the treatment of access stenosis.13,38,53,66,103,111,112,119,174-178
The potential long-term patency rate following PTA is well established.103,111,112,119,174-177 Published series consistently report 40% to 50% 6-month unassisted patency rates from PTA. Long-term unassisted patency after surgical revision is less well established due to reporting of cumulative patency.13,38,66 The Work Group believes that a 50% 1-year unassisted patency after surgical revision should be the goal. Treatment of stenoses postthrombosis yields lower primary patency rates than elective correction of stenoses detected by monitoring. This observation suggests that thromboses are associated with more critical stenoses166 (see Guideline 21: Treatment of Thrombosis and Associated Stenosis in Dialysis AV Grafts).
Surgical revision is held to a higher standard than PTA because surgical revision usually extends the access farther up the extremity by the use of a jump graft. Thus, more vein is used in surgical revision than in PTA.
Individual patients may have rapid recurrence of stenosis that requires repeated PTA.103,111 In these patients, repeated PTA may not be cost-effective, prompting surgical revision. The Work Group recommends defining PTA failure as the need for more than two PTA interventions within a 3-month interval.177
The unassisted patency of stents in hemodialysis access is no better than that following PTA, except in elastic stenoses.36,179-183 Thus, stents should be reserved for surgically inaccessible stenoses that fail PTA.
Arterial inflow stenoses are relatively uncommon.9,103,109,119 They usually manifest themselves as an inability to achieve target blood flow due to increased negative arterial pre-pump pressure.
Treatment of Central Vein Stenosis
Percutaneous intervention with transluminal angioplasty is the preferred treatment for central vein stenosis.
Stent placement combined with angioplasty is indicated in elastic central vein stenoses or if a stenosis recurs within a 3-month period. (Evidence)
Rationale Early detection and treatment of central vein stenosis reduces the rate of thrombosis and increases the likelihood of preserving an existing extremity for future access.9,109,119,163,179 Surgical treatment of central vein stenosis requires thoracotomy and should be avoided. Stents improve patency in subclasses of patients with elastic stenoses and in patients with early recurrence of stenoses.15,20,103,112,179,180,183
Treatment of Thrombosis and Associated Stenosis in Dialysis AV Grafts
Thrombosis Treatment Thrombosis of an AV graft should be corrected with surgical thrombectomy or with pharmacomechanical or mechanical thrombolysis. The choice of technique to treat thrombosis should be based on the expertise of the center. However, it is essential that:
A. Treatment be performed rapidly following detection of thrombosis to minimize the need for temporary access. (No more than one, and preferably, no femoral vein catheterization should be required.) (Opinion)
B. The access be evaluated by fistulogram for residual stenosis postprocedure. (Evidence)
C. Residual stenosis be corrected by angioplasty or surgical correction. (Evidence) (Note: Outflow venous stenoses are present in >85% of instances of thrombosis; the need for PTA or surgical revision is expected in most instances.)
D. The procedure be performed as outpatient procedure under local anesthesia. (Access revision may require up to a 24-hour observation to evaluate swelling and steal.) (Opinion)
E. Monitoring tests used to screen for venous obstruction should return to normal following intervention (see Guidelines 10, 17, and 18). (Evidence)
Patency goals following thrombosis. Centers should monitor outcome results on the basis of patency; minimum reasonable goals (for the center as a whole) for percutaneous thrombolysis and surgical revision thrombectomy should be:
Percutaneous thrombolysis with PTA: 40% unassisted patency and functionality at 3 months (Evidence)
Surgical thrombectomy and revision: 50% unassisted patency and functionality at 6 months and 40% unassisted patency and functionality at 1 year (Opinion)
Immediate patency*: 85% for both techniques (Evidence/Opinion)
Rationale Available data do not indicate a clear-cut preference between surgical thrombectomy and revision and percutaneous mechanical or pharmacomechanical thrombolysis. Comparative studies163,164,184-186 show conflicting results, with similar technical success rates and long-term patencies between these methodologies. Noncomparative studies do not yield a definitive preference.13,14,38,53,66,103,158-162,178,187,188 In the Work Groups opinion, current data suggest surgical thrombectomy and mechanical and pharmacomechanical thrombolysis are all effective for resolving thrombosis.
Thrombosis is associated with underlying venous stenosis in >85% of instances.13,14,38,66,158- 162,178,187 It is essential that fistulography is performed rapidly to prove the stenosis is corrected. Failure to do so will result in rapid repeat thrombosis.13,66
Delay in restoring access will result in the need for temporary catheters. The Work Groups consensus is that the placement of more than one temporary femoral catheter while awaiting thrombosis correction is unwarranted. Placement of a central vein catheter while awaiting thrombosis treatment is also unwarranted.
General anesthesia and hospitalization add to the risk and cost of treatment respectively and should be avoided when possible.
Patency rates. Stenosis accompanied by thromboses are more difficult to treat than stenoses detected by prospective monitoring; treatment of stenoses associated with thrombosis is therefore associated with poorer outcomes for both surgical and percutaneous techniques. Percutaneous techniques yield 90-day patencies ranging from 30% to 40%; 40% is an acceptable goal.160-162,187 Surgical unassisted patency is difficult to determine due to reporting of cumulative patencies; it is approximately 50% at 6 months and 20% at 1 year.164,185,186 The Work Group recommends goals of 50% unassisted patency at 6 months and 40% unassisted patency at 1 year.13,14 Surgical correction of stenoses is held to a higher standard than PTA because the access is usually extended farther up the extremity when surgical revision is performed.
Treatment of Thrombosis in Primary AV Fistulae
Thrombosis of an AV fistula is difficult to treat. Neither percutaneous nor surgical techniques offer good results. Each institution should attempt to resolve thrombosis with the technique that is preferred at that institution. (Opinion)
Rationale Little data on the success of treating thrombosis in native AV fistulae are reported. The Work Group believes that treatment of thrombosis in native AV fistulae is not as successful as treatment of thrombosis in AV grafts. Some authors have reported success with various techniques.189
Treatment of Tunneled Cuffed Catheter Dysfunction
Catheter dysfunction is defined as failure to attain and maintain an extracorporeal blood flow sufficient to perform hemodialysis without significantly lengthening the hemodialysis treatment. The Work Group considered sufficient extracorporeal blood flow to be 300 mL/min. (Opinion)
Urokinase is currently not available on the US market. Preliminary studies using thromboplastin activator (TPA) and recombinant urokinase (rUK) in the treatment of hemodialysis catheter dysfunction are underway and appear promising. At this time neither agent has sufficient evidence for the guidelines to recommend their wholesale adoption.
A. A dysfunctional catheter should be treated in the hemodialysis unit using the protocol for intraluminal urokinase administration (see Table III-2 in Guideline 6: Acute Hemodialysis Vascular AccessNoncuffed Catheters). (Evidence)
B. If urokinase treatment fails, a radiographic study using catheter contrast injection should be performed. Further treatment should then be performed based on the radiographic findings. Appropriate treatments include:
1. Fibrin sheath stripping using a snare if a fibrin sheath is present (Evidence)
2. Exchanging the thrombosed catheter over a guidewire if a fibrin sheath is present or if the catheter is malpositioned or of inadequate length (Evidence)
3. Intra-catheter urokinase infusion (eg, 20,000 units/lumen/hour) for 6 hours if a fibrin sheath is present or a luminal thrombosis remains (Evidence)
4. Performing embolectomy on the catheter if the lumens show residual thrombus (Opinion)
5. Repositioning a malpositioned catheter using a snare (Evidence)
Rationale Thrombosis of catheter lumens is the most common cause of catheter dysfunction.73,128 The urokinase protocol78,128 (see Table III-2, Guideline 6) is successful in resolving the thrombus in 70% to 90% of instances.128 This protocol should be attempted as the first procedure to resolve catheter thrombosis because it is the least invasive and least costly of all catheter salvage techniques.
Catheter imaging with contrast infusion will identify other correctable problems (residual lumen thrombus, external fibrin catheter sheath, malpositioned catheter tip). Treatment of fibrin sheath formation may include fibrin sheath stripping, guidewire catheter exchange, and urokinase infusion.78,79,190 Any of the three techniques are acceptable options for correcting fibrin sheath adherence to cuffed catheters.
Intraluminal residual thrombosis may be treated with urokinase infusion or with catheter embolectomy. The Work Group concluded that both procedures are effective for treating intracatheter thrombosis that does not respond to the urokinase protocol.
Catheter malposition may be corrected by snare-mediated catheter repositioning or by exchange of the catheter over a guidewire.78,79 The Work Groups opinion is that both methods are effective. Catheters of inadequate length should be exchanged over a guidewire to the appropriate position or replaced.
Additional data are emerging on the role of continuous thrombolytic therapy, as opposed to mechanical therapy, in the treatment of malfunctioning catheters. Preliminary evidence suggests that continuous three hour infusion of 250,000 units during the dialysis treatment may also be effective treatment of fibrin sheath. Further studies of the use of continuous urokinase infusions are pending. Currently urokinase (Abbott) is not available on the North American market. Preliminary studies utilizing recombinant urokinase and thromboplastin activator TPA are underway.
Treatment of Infection of Dialysis AV Grafts
Local infection of a dialysis AV graft should be treated with appropriate antibiotics based on culture results and by incision/resection of the infected portion of the graft. (Evidence)
Extensive infection of a dialysis AV graft should be treated with antibiotics and total resection of the graft. (Evidence)
Infection of a newly placed graft (ie, within 1 month) should be treated with antibiotics and by removing the graft, regardless of the extent of the infection. (Opinion)
Initial antibiotic treatment should cover both Gram-negative and Gram-positive organisms and should cover Enterococcus. (Opinion)
Rationale Infection involving an AV graft has been demonstrated to require both antibiotic therapy and surgical therapy to achieve cure in the vast majority of cases.14,191,192 Superficial infection that does not involve the graft may respond to antibiotic therapy alone. Antibiotic therapy should be based on culture results but initially should include both Gram-negative and staphylococcal and streptococcal coverage because of the likelihood of both Gram-negative and Gram-positive infection. An increasing trend toward enterococcal infection warrants coverage of this organism until culture results are obtained.
A newly placed graft is not incorporated into the surrounding tissue; thus, in the Work Groups opinion, even a localized infection of a new graft requires total removal of the graft. (For management of established AV grafts that are infected, see Guideline 17: When to Intervene Dialysis AV Grafts for Venous Stenosis, Infection, Graft Degeneration, and Pseudoaneurysm Formation.)
Treatment of Infection of Primary AV Fistulae
Infections of primary AV fistulae are rare and should be treated as subacute bacterial endocarditis with 6 weeks of antibiotic therapy. Fistula take-down is required in cases of septic emboli. (Opinion)
Rationale Native AV fistulae infections have been shown to respond well to antibiotic therapy without fistula removal in most instances. The Work Group believes only septic emboli warrant take-down of the fistula.
Treatment of Infection of Tunneled Cuffed Catheters
Tunneled cuffed catheter infection is a serious problem. Appropriate treatment is dependent upon the nature of the infection:
A. Catheter exit site infectionscharacterized by redness, crusting, and exudate at the exit site in the absence of systemic symptoms and negative blood culturesshould be treated as follows:
1. Apply topical antibiotics, ensuring proper local exit site care; do not remove the catheter. (Opinion)
2. If there is tunnel drainage, treat with parenteral antibiotics (anti-staphylococcal, anti-streptococcal therapy pending exit site cultures) in addition to following appropriate local measures. Definitive therapy should be based on culture results. Do not remove the catheter unless the infection fails to respond to therapy. If the infection fails to respond to therapy, remove the catheter and replace it using a different tunnel and exit site. (Evidence/Opinion)
B. Catheter-related bacteremia, with or without systemic signs or symptoms of illness, should be treated by initiating parenteral treatment with an antibiotic(s) appropriate for the organism(s) suspected, usually Staphylococcus and Streptococcus. (Evidence) Definitive therapy should be based on the organism(s) isolated. (Evidence) The catheter should be removed in all instances if the patient remains symptomatic more than 36 hours. (Evidence) The catheter should also be removed in any clinically unstable patient. (Opinion) Preliminary reports suggest that after obtaining a bactericidal level of the antibiotic in the blood, in a stable asymptomatic patient without exit site or catheter tunnel tract involvement may be treated by changing the catheter over a guidewire plus a minimum of 3 weeks of systemic antibiotic therapy. Blood cultures should be repeated periodically during and immediately after this treatment to monitor its effectiveness.
A new permanent access should not be placed until blood cultures, performed after cessation of antibiotic treatment, have been negative for at least 48 hours. (Opinion)
Rationale Infection is one of the leading causes of catheter removal and morbidity in dialysis patients.70,78,153 Catheters associated with exit site infections alone can usually be salvaged without the need for catheter replacement.70,71,73 Catheter-mediated bacteremia is the major reason for catheter loss78 and has been associated with substantial morbidity, including metastatic infection.81 Catheter-mediated bacteremia is a life-threatening condition requiring initial hospitalization and parenteral antibiotic therapy. Unstable patients require removal of the catheter for rapid response to therapy. Despite initial reports of success (catheter salvage) with an "antibiotic lock" technique193 in a recent large trial of patients with catheter-mediated bacteremia, systemic antibiotics alone were able to salvage less than 25% of catheters.153 Most infections recurred as soon as the antibiotics were discontinued. In contrast, a preliminary study using catheter guidewire exchange in stable patients without tunnel involvement was able to salvage most catheters without apparent ill effects.80 Bacteremia with tunnel tract involvement should prompt catheter removal. The Work Group believes that 3 weeks of systemic antibiotic therapy are needed to treat catheter-associated bacteremia and that new permanent access should not be placed until cultures have been negative for at least 48 hours after cessation of antibiotic therapy.
Treatment of Pseudoaneurysm of Dialysis AV Grafts
Needle insertion into the area of pseudoaneurysm should be avoided. (Opinion)
Pseudoaneurysm of a dialysis AV graft should be treated by resection and insertion of an interposition graft if the pseudoaneurysm:
A. Is characterized by rapid expansion in size (Evidence/Opinion)
B. Exceeds twice the diameter of the graft (Opinion)
C. Threatens viability of the overlying skin (Opinion)
D. Is infected (Evidence)
Rationale Insertion of needles into a pseudoaneurysm may result in hemorrhage and should be avoided. A pseudoaneurysm is most effectively treated by resection and segment interposition.53,169 Pseudoaneurysms that are not resected may expand and rupture, resulting in significant blood loss. Pseudoaneurysms that exceed twice the diameter of the graft or those that are increasing in size should be surgically corrected due to their increased risk of rupture. Pseudoaneurysm expansion that threatens the viability of the skin places the patient at risk of graft infection. In these cases, surgical correction is indicated.
Aneurysm of Primary AV Fistulae
Aneurysms of primary AV fistulae require surgical intervention only when the aneurysm involves the arterial anastomosis. Venipuncture should avoid the aneurysm. (Opinion)
Rationale Aneurysms develop as a matter of course in AV fistulae. Their natural history is benign. The Work Group recommends revision only if the aneurysm involves and compromises the arterial anastomosis. Venipuncture should avoid the aneurysm due to the risk of difficult hemostasis in the area of the aneurysm.
*Unassisted patency is defined as patency until either a thrombosis or access failure or an intervention to prevent thrombosis is performed.
*Immediate patency is defined as patency to next hemodialysis session.
© 2001 National Kidney Foundation, Inc