Vascular Surgery Cases: Detours

Brian F. Stull, RDMS, RVT

UNC REX Healthcare

Vascular Specialists

Brian.Stull@Unchealth.unc.edu

Objectives• Anatomy of a bypass graft

• Where does it connect, where does it course?

• How to approach and perform duplex exams on bypass grafts

• What do grafts look like by duplex?

• What can I expect to find when I perform an exam?• What does normal look like?

• What does abnormal look like?

• Examples of graft surveillance and maintenance

• What happens when grafts fail?

Diagnosis and Treatment of Chronic Arterial Insufficiency of the Lower Extremities: A Critical ReviewJeffrey I. Weitz, MD, Chair; John Byrne, MD; G. Patrick Clagett, MD; Michael E. Farkouh, MD; John M. Porter, MD; David L. Sackett, MD; D. Eugene Strandness, Jr, MD; Lloyd M. Taylor, MD

Reasons for a Bypass?

•Critical Limb Ischemia with no other options (stenting, angioplasty)

•Non-healing wound(s)

•Poor position for stenting

First Things First…… Know Who You Are Dealing With

Who is the more likely person to have a bypass graft?

The patient will have more than one level of disease, very likely

Where do I start?!?!

• OPERATIVE REPORT!!! Without it you’re hunting

• Previous duplex exam. WINNER!

• Always refer to your protocol; however, these are the levels that must be evaluated

• Inflow Artery

• Proximal Anastomosis• Bypass Conduit

• Distal Anastomosis

• Outflow Artery

• If any one point is faulty there is a danger for failure

Some Common Criteria

• Peak Systolic Velocities, “Normal” >50 to <200 cm/s

• Change in ABI at follow up 30% < or > previous

• PSV abnormal Low <45 cm/s*

• PSV abnormal High >200cm/s

• 50-75% stenosis Ratio >1.5 to 3.5

• 75+% stenosis Ratio >3.5

First you have to know what “normal” is

Inflow Artery: It all starts here

In lower extremity inflow is usually via common femoral artery

But not always…….

Proximal Anastomosis: Get off to a good start

Gray scale image looking

for abnormalities, thrombosis,

Intimal hyperplasia

Color Doppler looking

for filling defects or flow

outside graft at anastomosis

PW Doppler documenting

flow velocities

Bypass Conduit: Need a good clean path

Interrogate the entire graft, anastomosis to anastomosis in gray scale and in both color and pulsed wave Doppler

Bypass Conduit Transverse Interrogation

Transverse views are critical to look for defects or abnormal courses.

Distal Anastomosis: Have to end well too

Same as with the proximal anastomosis, Doppler and gray scale

Outflow Vessel: This is the landing zone

Just like having adequate inflow is necessary, so is adequate outflow

How do they do that? Magic?

Nope: TUNNELLING

Oh, so like this?

No, that would end up more like this….

Exactly like this….. Need a nice tight fit

Dr. Bobby Mendes, REX Vascular Specialists

Bypass Graft Examples

Axillo-Bi-Fem

PTFE and VEIN Graft Duplex Appearance

Vein Graft

PTFE Graft

Carotid to Subclavian BypassReally? Yes, really

Occluded subclavian with inadequate collateral flow to arm

Approaching an Incision = Scar Tissue

Angle back into the incision from the side

Following an Axillary to Fem-Fem Bypass Graft Patient• History of failed Aorta Bi-Fem bypass graft

• Left axillary to left femoral bypass graft with left to right fem-fem bypass graft

• June 2015 stenting of the proximal anastomosis due to stenosis

• February 2016 duplex shows subclavian stenosis with retrograde left vertebral artery flow, and stenosis in stent in the proximal bypass graft, patient had knee replacement and is minimally ambulatory, intervention is scheduled

Duplex and Angio Findings Differ on Subclavian Steal

• Duplex shows subclavian stenosis with steal from the vertebral artery

• Angiography shows no evidence of subclavian stenosis What??

336.1cm/s

Duplex and Angio Findings of Proximal Anastomosis/Stent Stenosis

• Velocity increase from 155.6cm/s PSV to

400.3cm/s PSV is >2.0 consistent with at

least a 50% stenosis

• Balloon angioplasty performed

Ax-Fem Bypass Surveillance

• July ABIs: Right 0.91 Left 0.89

• Patient asymptomatic

• No intervention, follow up in 3 months

• October ABIs: Right 0.64 Left 0.62

• Patient having claudication

• Stenosis identified at proximal anastomosis

• Intervention scheduled

412.7cm/s PSV

=>200cm/s PSV & 2.33 Ratio

SFA to Posterior Tibial Artery Bypass using Saphenous Vein

Distal Anastomosis

Bypass Outflow (run-off) Vessel

402cm/s PSV

117cm/s EDV

WRONG

68.2cm/s PSV

18.9cm/s EDV

Angiography and Balloon Angioplasty

Duplex Exam Status Post Intervention: Prox Anastomosis

Duplex Exam Status Post Intervention: Distal Anastomosis and Outflow Vessel

Fem-PTA: Saphenous Vein to PTFE Jump Graft

44.6cm/s PSV

Edema in Tunneled track causing Extrinsic Compression

52.8cm/s PSV 252.1cm/s PSV

Saphenous Vein to PTFE Jump to Posterior Tibial Artery

41.0cm/s PSV7.0cm/s PSV

PTFE Jump to Posterior Tibial Anastomosis

77.1cm/s PSV

To Intervene or not to Intervene?

• Surgery costs money

• People don’t like having surgery

• Patient’s wounds are healing, no other symptoms

• Let’s watch it and see how it does

• Come to the Emergency Department with onset of new symptoms (i.e. Pain, cold foot)

Emergency Department 3 days later………dangit!

Thrombosed due to low flow state

Proximal Anastomosis PTFE at Distal aspect of bypass

Sometimes you just can’t see much

Iliac to SMA bypass Prox Anastomosis

Unfortunately it is usually just a matter of time

April September

Thrombosed graft with compression

NOTES……

NOTES……