Lower and Upper Arterial Duplex Upper Venous Duplex Fistuals Grafts
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What are some reasons for performing arterial and venous duplex exams? (9)
- 1.) stenosis vs. occlusion
- 2.) stenosis diameter reduction
- 3.) grafts- bypass artery to artery and hemodialysis access
- 4.) aneurysms
- 5.) AV fistulas
- 6.) Venous thrombosis (DVT)
- 7.) Radial A. harvesting
- 8.) Preoperative evaluation
- 9.) Evaluate venous system: measure the size of the vein
Define Paget-Schroetter Syndrome
Effort thrombosis of the upper extremity caused by hypertrophied muscle or congenital abnormalities of TOA (thoracic outlet area).
What vessels are involved with Paget-Schroetter Syndrome?
axillary and/or subclavian veins
Define primary paget-schroetter syndrome. (3)
Idiopathic and has a high risk of death.
Up to 1/3 of patients present with PE.
Define secondary paget-schroetter syndrome.
Venous thrombosis develops in patients with central venous catheters, pacemakers, or cancer and accounts for most cases.
What are the normal velocities in arterial duplex scanning?
CFA = 115 +- 25 cm/sec
SFA = 90 +- 15 cm/sec
POPA = 69 +- 15 cm/sec
Tib = 61 +- 20 cm/sec
What do we look at when doing arterial duplex scanning?
What are A-V Fistulas?
Arteriovenous Fistula (AVF)
An abnormal communication between an artery and a vein that maybe congenital or acquired by cardiac catheterization or surgically made by a vascular surgeon.
What vessels are involved in the three most common AVF?
1.) Radial artery and cephalic vein connected.
2.) Median Cubital branch of cephalic V. and Distal brachial A.
3.) Basilic V. and Brachial A.
Which AVF is known as Brescia-Cimino Fistula?
Radial artery and cephalic vein
What would anatstomosis look like on sonographic images?
causes high velocities and turbulent flow
What are the three most common AVF and what are their locations?
1.) radiocephalic at the wrist
2.) brachiocephalic at the antecubital fossa
3.) Brachiobasilic vein
Why would AVF be created on purpose? (3)
Patients with ESRD need to dialyze to filter their blood because the kidneys do not function any longer in this capacity.
Hemodialysis is a way patients eliminate excess fluid and wastes form the blood.
What does ESRD stand for?
end-stage renal disease
Where would vascular surgeons want to put the AV fistula first?
1.) in forearm of non-dominate arm
2.) move up to upper arm
3.) or even upper thigh
What is the process with hemodialysis?
1.) 2 15-guage needles placed into the AV fistula into the dialyzer
2.) 1 needle is placed more distal in the AV fistula. (the needle carries blood from the patient to the dialyzer).
3.) 2 needle is placed more proximal in the AV fistula and returns blood to the patients circulation.
What is the most common way grafts are anastomosed to arteries?
The end of the graft is joined to the side of the native artery.
What happens with Brescia Cimino AVF? (6)
1.) use non-dominant arm
2.) radial A to cephalic V or basilica v to ulnar A.
3.) Flow goes through vein because it is the path of least resistance
4.) Vein enlarges and dilates out, get a large volume of flow and velocities.
5.) Will feel a thrill (BEE)
6.) bruit- you will hear b/c high velocites
What are the 4 most common shapes of grafts?
- 1.) Forearm loop graft
- 2.) Upper arm straight graft
- 3.) Axillary loop graft
- 4.) Thigh graft
What three main shapes can Gortex-synthetic grafts be made out of?
- 1.) Straight
- 2.) Looped
- 3.) Tapered (onto arterial end to reduce flow)
What is the material that gortex-synthetic grafts are usually made from?
What are 8 complications to grafts?
- 1.) develop thrombosis/occlusions of arterial or venous side.
- 2.) Develop stenosis occurs at the proximal or distal anastomosis site.
- 3.) Venous anastomosis slower flow more likely to develop stenosis
- 4.) Infection-primary with synthetic
- 5.) Arterial steal- Not getting it to the hand
- 6.) Venous hypertension
- 7.) Aneurysm and pseudoaneurysms
- 8.) Rt. side heart pressure becomes elevated.
What are 5 things to do when imaging grafts?
- 1.) get a good patient history
- 2.) visualize and palpate arm
- 3.) use color
- 4.) evaluate inflow artery and outflow vein
- 5.) proximal artery before anastomosis
What are 3 normal results from imaging a graft?
- 1.) high flow/low resistance
- 2.) spectral broadening
- 3.) when taking peak velocity measurements expect 100-400 cm/sec
What are 2 things that would signify that a graft is occluded?
- 1.) NO flow in graft = no color
- 2.) High resistance signal again in artery
What are 3 things that signify that a graft is has a stenosis?
- 1.) Mild-velocities increase < 50% of functioning
- 2.) Moderate-velocities increase 50-90 %
- 3.) Severe-velocities >100% increase
What two things will you have to do with machine adjustments to detect stenosis in a graft?
- 1. adjust PRF
- 2.) spectral scale
Where do you take flow volume measurements within the graft?
What formula do you use to get flow volume measurements within the graft?
What units do you get for flow volume?
Take in the middle of graft.
area X time average velocity X 60 seconds = Flow volume Rate
What are the measurements for flow volume within a graft for:
-Poor dialysis graft =
-Normal dialysis graft =
-Too much flow volume =
-Poor dialysis graft = < 250 mL/min
-Normal dialysis graft = 300-1000 mL/min
-Too much flow volume = >1200 mL/min
When there is too much flow volume within a graft what can happen to the patient?
put the patient into CHF
What is a thrombectomy?
removal of a blood clot with surgery
What is the term to describe removal of a blood clot with surgery?
What can both an AV Fistula and a graft do?
both can be used for Hemodialysis access
What is the difference between AV fistulas and grafts?
AV Fistulas- vein and artery connected together directly with anastomosis.
Graft- placed between vein and artery but still connects them.
What would you like to do?
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