Chapter 174 - Acquired arteriovenous fistulas Flashcards
First description of acquired AVF
William Hunter 1761 attempted phlebotomy
Bruit and thrill descriptions
Traumatic causes of AVF
1) stab wounds 63%
2) gun shot 26%
3) blunt 1%
Iatrogenic AVF most common location
CFA 37%
Rate of access complications using fluoroscopy or US
fluoroscopy 3.4%
US 1.4%
Spontaneous AVF first described by and definition
Syme 1831
1) atherosclerotic
2) inflammatory
3) mycotic aneurysm
4) other infections and connective tissue diseases (rare)
Rate of neck injuries resulting in carotid jugular AVF
4-27%
Causes of vertebral artery AVF
1) iatrogenic 2/3
2) trauma 1/3
AVF rate after subclavian vein catheterization
0.58%
Iatrogenic AVF in radial and ulnar arteries rate
0.02-0.04%
Incidence of CFA AVF iatrogenic
0.06-0.86%
Factors predisposing iatrogenic femoral AVF
1) female
2) emergency procedure
3) anticoagulation
4) low distal puncture
5) HTN
6) prosthetic graft
7) age > 65
8) sheath > 8F
9) high BMI
10) femoral atherosclerosis
11) left-sided
12) multiple punctures
13) hostile groin
Popliteal AVF as a % of all AVF
5-14%
Cause of aorto-caval fistula
1) rupture or erosion of AAA (80-90%)
2) penetrating injury (10-20%)
Lumbar disc procedures in causing AVF key points
1) rate 0.05%
2) risks with low aortic bifurcation at L4-L5
3) most common CIA injury right 43%, left 29%)
risk of biopsy causing renal AVF
9-18%
1) large bore needle
2) lack of radiologic guidance
3) medullary penetration
4) atherosclerosis
Causes of renal AVF
1) biopsy
2) nephrostomy tube
3) laser lithotripsy
4) mass ligation of renal pedicle
Causes of splenic AVF
1) trauma/iatrogenic
2) mass ligation of splenic pedicle
3) erosion of pancreatic pseudocyst
4) rupture of noncalcified splenic artery aneurysm
Causes of hepatic AVF
1) trauma/iatrogenic
2) transhepatic diagnostic catheterization
3) biliary drainage
4) TIPS
5) biopsy 5.4% risk
6) carcinoma
7) aneurysm
Fistula size critical point for affecting normal arterial flow
Holman and Taylor
<1.5x diameter of inflow artery: normal arterial flow
>1.5x: 5x increase proximal artery flow
>3x diameter: diminished or reversed flow and 8x increase in proximal artery flow
> 350ml/min = cannot close spontaneously
Chronic changes with AVF
2 months: structural changes become evident
15 months: established but may be reversible
2 years: irreversible changes
Clinical presentation of AVF
75% small asymptomatic
Thrill/bruit 61-96%
Pulsatile mass 20-52%
Pain 70-80% (aorto/iliac avf)
Nicoladoni-Branham sign
Temporary compression of artery proximal to fistula resulting in bradycardia and decrease pulse pressure
signs of an aortocaval fistula
1) holosystolic murmur 75%
2) thrill 25%
3) CHF
CTA diagnosis of AVF sen and spe
Sensitivity 90-95%
Specificity 99-100%
Percentage of iatrogenic femoral AVFs that will close in 1 year
38-81%
Renal AVFs that resolve within 4 years spontaneously
33-90%
Compression therapy to treat AVF key points
1) low success rate 0-30%
2) long duration 15+days
3) skin ulcerations and DVTs
Onyx is made of
Ethylene vinyl alcohol copolymer
Success rate of embolization of small AVFs
89-92%
Endovascular tools for treating AVF
1) embolization material
2) covered stents
3) amplatzer plugs
Timing before normalization of cardiac, pulmonary and renal function of truncal AVF
Cardiac/pulmonary - immediate
Renal 48-72 hours
Surgical repair of post-cath AVF success rate
89-96%
Mortality and morbidity following spontaneous aorto-caval fistula
mortality 7-12%
Morbidity 36%: MI, PE, CVA, organ failure
Success rate of stent + embolization in neck and arm AVF
83.9-100%
Stent graft occlusion, restenosis (>50%), reintervention and mortality following neck and UE AVF embolization + stent
Occlusion: 5-10%
Restenosis 4-20%
Reintervention 6-12%
Mortality 0-5.9%
Aortocaval fistula endo success
84-94%
Aortocaval fistula endo repair mortality and morbidity
Mortality 0-19%
Morbidity 12-46%
% of renal AVF that require treatment
23-36%
Embolization of renal AVF +/- stent graft success rate
90%
Visceral artery aneurysm success rate of coil embolization
93.3-100%
Mortality and morbidity of visceral artery aneurysm endo repair
Mortality 0-8.3%
Morbidity 10-12.5%
Mortality and morbidity after splenic artery aneurysm reapir
Mortality 0%
Morbidity 40% splene infarction
Mortality after hepatic aneurysm embolization
11%
Decision to treat with open vs endo for AVF’s
No real difference
