Transcript
Dialysis Access Interventions
“Preservation of arteriovenous access”
Matt Hawkins, MDAssistant Professor – Emory University SOM
Introduction
• Understand basic construction and function of AV fistulas and grafts
• Review endovascular interventions for non-thrombosed AV fistulas and grafts
• Review endovascular interventions for thrombosed fistulas and grafts
Construction and Function
Construction and Function
• NKF-KDOQI = at least 65% fistulas• All new patients with ESRD
• Typical fistula failure rates after construction = 15%-25%
• Fistula maturity time = 3-4 months• Balloon-assisted maturation = 74-94%
salvage of non-maturing fistulas
Construction and Function
• Fistulas are ready to use when:• Flow > 600 mL/min• Vein diameter > 0.6 cm• Depth under the skin < 0.6 cm
• Diameter > 4mm and flow > 500 mL/min = 95% likelihood of successful dialysis1
1:Robbin et al. Hemodialysis arteriovenous fistula maturity: US evaluation. Radiology 2002.
Construction and Function
• AV Grafts – looped configuration from brachial artery to brachial vein preferred.
• May be used within 14 days of placement
• Primary 1 yr patency = 40%• Secondary 1 yr patency = 60-90%
• Most common reason for graft failure?
Construction and Function
• SURVEILLANCE• Flows < 400 mL/min• Increased bleeding after dialysis• Increased pulsatility• Increased swelling
• 50-90% decrease in thrombosis rate with monitoring and surveillance and with early venous stenosis angioplasty
Endovascular Interventions
• NON-THROMBOSED FAILING ACCESS
• Comparably miserable for surgical and endovascular repair (25% patency at 6 months)
Endovascular Interventions
• NON-THROMBOSED FAILING ACCESS• Commonly Venous outflow in FISTULAS• Brachiocephalic = cephalic arch (39%)• Primary patency rate w/ angioplasty
(3, 6, & 12 mos) = 96%, 83%, 75%• Brachiobasilic transposition = “swing”
site• Arterial stenoses = < 15%
Endovascular Interventions
• NON-THROMBOSED FAILING ACCESS• PTFE graft angioplasty results:• 50% 6 month primary patency• Angioplasty-enabled patency = 68% at
1 year; 51% at 2 years• Secondary patency rates = 82% at 1
year; 65% at 2 years
Endovascular Interventions
• NON-THROMBOSED FAILING ACCESS• PTFE graft angioplasty results:
• NKF-KDOQI endorses Secondary patency of:
• 70% at 1 year• 60% at 2 years• 50% at 3 years
Endovascular Interventions
• NON-THROMBOSED FAILING ACCESS• Venous outflow stenosis in a graft,
consider covered stent
Endovascular Interventions
• PTFE stent = 38% 6 month patency of circuit• Angioplasty = 20%
• PTFE stent = 32% freedom from intervention
• Angioplasty = 16%
Endovascular Interventions
• NON-THROMBOSED FAILING ACCESS• Fistula angioplasty results:• WIDELY VARIABLE• 55% 6 month primary patency• 80% 6 month assisted primary patency• 82% 6 month secondary patency
Clark et al. Outcome and prognostic factors of restenosis after percutaneous treatment of native hemodialysis fistulas. JVIR 2002.
Endovascular Interventions
• NON-THROMBOSED FAILING ACCESS
Endovascular Interventions
• NON-THROMBOSED FAILING ACCESS
Endovascular Interventions
• NON-THROMBOSED FAILING ACCESS
DE-CLOT
Endovascular Interventions
• THROMBOSED ACCESS
• Pre-procedure work-up• K+• Right-to-left shunt• Prior procedures
Endovascular Interventions
• THROMBOSED ACCESS
Endovascular Interventions
• THROMBOSED ACCESS
Endovascular Interventions
• THROMBOSED ACCESS• Outcomes for PTFE grafts:• 90% initial clinical success (at least 1
round of dialysis)• 1 year primary patency = 11-26%• 1 year secondary patency = 51-69%
• Surgical and endovascular methods demonstrate similar patency rates
Endovascular Interventions
• THROMBOSED ACCESS• Outcomes for FISTULAS:• Technical success 75-100%• 18-60% primary patency at 6 months• 60-80% primary assisted patency at 6
months
Endovascular Interventions
• THROMBOSED ACCESS• Three ways to declot thrombosed access:
1. Pulse-spray thrombolysis2. Lyse-and-wait (“Lyse-and-go”)3. Mechanical thrombectomy
They all work!
How do we declot
dialysis access?
Endovascular Interventions
• TECHNIQUE
Endovascular Interventions
• TECHNIQUE• Micropuncture access both directions• Infuse 4 mg tPa in 10mL saline• Split between the two catheters
• Wait, prep remainder of equipment
Endovascular Interventions
• TECHNIQUE• 6F sheaths, bilaterally (radio-opaque tip)• Wire access both directions• Pull-back venogram to level of venous
outflow clot• Heparin• Venous outflow angioplasty/balloon
maceration (start with 6 mm Conquest)
Endovascular Interventions
• TECHNIQUE• Compliant balloon (Python/Fogarty) over
wire in artery (through anastamosis)• Pull back arterial plug into shunt• Repeat venous outflow
angioplasty/maceration• Repeat angiogram• Treat residual stenosis within the dialysis
circuit and centrally
Endovascular Interventions
• TECHNIQUE
Endovascular Interventions
• TECHNIQUE
Endovascular Interventions
• TECHNIQUE
Endovascular Interventions
• TECHNIQUE
Endovascular Interventions
• OTHER CONSIDERATIONS• Venous collateral embolization• Ischemia/steal syndromes• Venous hypertension (central occlusion)• Aneurysms/pseudoaneurysms
Endovascular Interventions
• OTHER CONSIDERATIONS• Current coding: • Access 36147, 36148• Angiography 35476, 75978• Thrombectomy 36870• Stent 37236, 37238• Venous embolization 37241
• TOTAL = 27.52 RVU
Endovascular Interventions
• COMPLICATIONS• Arterial embolization (up to 10%)• Peri-graft bleeding• Vein rupture from angioplasty
Endovascular Interventions
• SUMMARY• As a general rule: 6 month primary
patency following angioplasty = 50%• Stent grafts may be superior to
angioplasty at the venous anastamosis of grafts
• As a general rule: 50-67% 1 year secondary patency after thrombosis
REFERENCES
Matt Hawkins, MD@MattHawkinsMD
matt.hawkins@emory.edu
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