Vascular Diagnostic Testing Optimum Re Charlotte A. Lee, M.D., DBIM, FLMI

Vascular Diagnostic Testing Part 2 Lower Extremities and Renal Arteries Charlotte A. Lee, M.D.

Screening Venous and arterial Duplex Venous and arterial Duplex Lower extremity Doppler Lower extremity Doppler Aortic ultrasound Aortic ultrasound Renal artery ultrasound Renal artery ultrasound Vein and arterial graft surveillance Vein and arterial graft surveillance Dialysis access surveillance Dialysis access surveillance

Evaluation of: Aorta Aorta Common femoral artery Common femoral artery Superficial femoral artery Superficial femoral artery Proximal deep femoral artery Proximal deep femoral artery Popliteal artery Popliteal artery Common and external iliac arteries Common and external iliac arteries Tibial arteries Tibial arteries

Abdominal Aorta Transverse and longitudinal views—proximal, mid and distal aorta Transverse and longitudinal views—proximal, mid and distal aorta Transverse view of common iliac arteries at the aortic bifurcation Transverse view of common iliac arteries at the aortic bifurcation Documentation of aneurysms, if present—measured outer wall to outer wall Documentation of aneurysms, if present—measured outer wall to outer wall

Abdominal Aorta

3-D CTA of AAA

Recommended Surveillance Less than 3 cm—no further testing Less than 3 cm—no further testing 3-4 cm—Every 12 months 3-4 cm—Every 12 months cm—Every 6 months cm—Every 6 months > 4.5 cm—Referral to vascular subspecialist > 4.5 cm—Referral to vascular subspecialist

Indications for Repair Aneurysm >5.5 cm in diameter Aneurysm >5.5 cm in diameter Expansion of >0.6 to 0.8 cm/year Expansion of >0.6 to 0.8 cm/year

Renal Artery Stenosis General population 0.1% General population 0.1% Hypertensive population 4.0 % Hypertensive population 4.0 % HTN and suspected CAD % HTN and suspected CAD % Malignant HTN % Malignant HTN % Malignant HTN and renal insufficiency 30-40% Malignant HTN and renal insufficiency 30-40% Prevalence increases with age: 7% over 65 yrs. Prevalence increases with age: 7% over 65 yrs.

RAS: Progression of atherosclerotic lesions

Testing Gold standard = Invasive renal arteriography Indicated when clinical suspicion high and results of noninvasive testing inconclusive

Magnetic Resonance Angiography Increasingly used as first line screening test Increasingly used as first line screening test Shows the renal arteries and perirenal aorta Shows the renal arteries and perirenal aorta Two small studies showed a sensitivity of 100% and specificity of 71-96% when compared to arteriography Two small studies showed a sensitivity of 100% and specificity of 71-96% when compared to arteriography Not useful for diagnosis of fibromuscular dysplasia that typically affects the middle and distal portions of the renal artery Not useful for diagnosis of fibromuscular dysplasia that typically affects the middle and distal portions of the renal artery

CT angiography Shows renal arteries and perirenal aorta Shows renal arteries and perirenal aorta Generally felt to have a sensitivity of 98% and specificity of 94% Generally felt to have a sensitivity of 98% and specificity of 94% Variable sensitivity in FMD Variable sensitivity in FMD Disadvantage: Nephrotoxic Disadvantage: Nephrotoxic

Duplex Doppler Ultrasonography Provides both anatomical and functional assessment of renal arteries Provides both anatomical and functional assessment of renal arteries Stenotic lesions are detected by comparing flow velocities of the renal artery to the aorta Stenotic lesions are detected by comparing flow velocities of the renal artery to the aorta In patients with high pretest probability of having RAS, sensitivity and specificity of 98% In patients with high pretest probability of having RAS, sensitivity and specificity of 98% Disadvantages: time consuming (2 hours), highly operator dependent Disadvantages: time consuming (2 hours), highly operator dependent

Fibromuscular dysplasia Frequently involves the distal 2/3 of the renal artery and branches Frequently involves the distal 2/3 of the renal artery and branches Characterized by “string of beads” appearance due to alternating fibromuscular webs and aneurysmal dilatation Characterized by “string of beads” appearance due to alternating fibromuscular webs and aneurysmal dilatation Total occlusion uncommon Total occlusion uncommon

Atherosclerosis Usually involves the proximal 1/3 of the main renal artery and perirenal aorta Usually involves the proximal 1/3 of the main renal artery and perirenal aorta In advanced cases, segmental and diffuse intrarenal atherosclerosis observed, particularly in ischemic nephropathy In advanced cases, segmental and diffuse intrarenal atherosclerosis observed, particularly in ischemic nephropathy

Renal Vein Thrombosis

Renal Vein Thrombosis—CT

Peripheral Circulation

Arterial Circulation

Ankle-Brachial Index (ABI) Used to predict the severity of peripheral arterial disease Used to predict the severity of peripheral arterial disease Ratio of the blood pressure in the lower legs to the blood pressure in the arms; the BP in the ankle is normally the same or greater than the BP in the arms Ratio of the blood pressure in the lower legs to the blood pressure in the arms; the BP in the ankle is normally the same or greater than the BP in the arms Determined by dividing the SBP in the arteries at the ankle/foot by the higher of the two SBP’s in the arms Determined by dividing the SBP in the arteries at the ankle/foot by the higher of the two SBP’s in the arms

Procedure Measurements are taken at rest Measurements are taken at rest Usually repeated after 5 minutes of walking on a treadmill* Usually repeated after 5 minutes of walking on a treadmill* * Even a slight drop in the ABI with exercise signals a high probability of PAD

Interpretation of ABI Ratio of the highest ankle to brachial artery pressure Ratio of the highest ankle to brachial artery pressure >1.3 is considered abnormal >1.3 is considered abnormal <1.0 is considered abnormal <1.0 is considered abnormal Abnormal result suggests calcification of the walls of the arteries, thus leading to incompressible vessels Abnormal result suggests calcification of the walls of the arteries, thus leading to incompressible vessels

Interpretation of ABI >1.2 Abnormal vessel hardening from PVD >1.2 Abnormal vessel hardening from PVD Normal range Normal range Acceptable Acceptable Some arterial disease Some arterial disease Moderate arterial disease Moderate arterial disease <0.5 Severe arterial disease <0.5 Severe arterial disease

Limitations > 1.3 indicates that vessels are so sclerotic/calcified that they cannot be compressed for accurate BP readings > 1.3 indicates that vessels are so sclerotic/calcified that they cannot be compressed for accurate BP readings Does not specifically identify which arteries are affected Does not specifically identify which arteries are affected

Segmental BP’s

Copyright ©2007 American Heart Association Yesenko, S. L. et al. Circulation 2007;115:e624-e626 Segmental leg pressure measurements with pulse-volume recordings

Predictability of ABI Studies in 2006 suggest that an abnormal ABPI may be an independent predictor of mortality, as it reflects the burden of atherosclerosis 1,2 Studies in 2006 suggest that an abnormal ABPI may be an independent predictor of mortality, as it reflects the burden of atherosclerosis 1,2

Venous Insufficiency Screening

Venous Valves

Purpose To evaluate the deep and superficial venous systems for evidence of valvular incompetence To evaluate the deep and superficial venous systems for evidence of valvular incompetence

Indications Pre-op evaluation Pre-op evaluation Venous ulcers Venous ulcers Lower extremity pain or heaviness Lower extremity pain or heaviness Visible varicose veins Visible varicose veins Pain, edema, discoloration Pain, edema, discoloration

Contraindications and Limitations Obesity Obesity Open draining ulcers Open draining ulcers Severe edema Severe edema Inability to stand for an extended length of time (patient has to be in reverse Trendelenberg or standing) Inability to stand for an extended length of time (patient has to be in reverse Trendelenberg or standing) May be seated for below-the-knee testing May be seated for below-the-knee testing

Direct Method Duplex evaluation for reflux to include 2-D structure and motion in real-time, color flow imaging, and Doppler US signal documentation Duplex evaluation for reflux to include 2-D structure and motion in real-time, color flow imaging, and Doppler US signal documentation

Indirect Method Photoplethysmographic sensors—vein is emptied and the filling time is recorded (venous refill time or VRT) Photoplethysmographic sensors—vein is emptied and the filling time is recorded (venous refill time or VRT)

Results If abnormal VRT normalizes with application of tourniquet above the knee  incompetence of GSV If abnormal VRT normalizes with application of tourniquet above the knee  incompetence of GSV If VRT remains abnormal, but normalizes with tourniquet below the knee, LSV incompetence is suggested If VRT remains abnormal, but normalizes with tourniquet below the knee, LSV incompetence is suggested If still abnormal, deep venous incompetence is suggested If still abnormal, deep venous incompetence is suggested

Deep Vein Thrombosis (DVT) Due to acute or chronic thrombophlebitis, frequently due to injury Due to acute or chronic thrombophlebitis, frequently due to injury Chronic stagnation leading to phlebothrombosis Chronic stagnation leading to phlebothrombosis

Studies Duplex ultrasound Duplex ultrasound Venogram—injection of contrast dye with radiographic imaging Venogram—injection of contrast dye with radiographic imaging

References 1. Feringa HH, Bax JJ, van Waning VH et al. (March 2006). “ The long-term prognostic value of the resting and postexercise ankle-brachial index”. Arch Intern. Med. 166 (5): Wild SH, Byrne CD, Smith FB, Lee AJ, Fowkes FG (March 2006). “Low ankle- brachial pressure index predicts increased risk of cardiovascular disease independent of the metabolic syndrome and conventional cardiovascular risk factors in the Edinburgh Artery Study”. Diabetes Care 29(3): Diabetes Care 29(3):