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 Review Jeffrey 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 Bypass Really? 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 336.1cm/s Angiography shows no evidence of subclavian stenosis What??
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 WRONG 68.2cm/s PSV 18.9cm/s EDV 402cm/s PSV 117cm/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 PSV 7.0cm/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! Proximal Anastomosis PTFE at Distal aspect of bypass Thrombosed due to low flow state
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
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