Noninvasive Vascular Diagnostic Laboratory. Peripheral Arterial Occlusive Disease
PERIPHERAL ARTERIAL OCCLUSIVE DISEASE
11. What is the primary test for diagnosis of lower extremity ischemia?
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The ankle brachial index (ABI) or systolic pressure ratio is normally greater than or equal to 1.0. Typically, Doppler ultrasound is used (instead of a stethoscope) as the flow sensor distal to the pressure cuff, but plethysmographic instruments also may be used. Doppler signals are usually monitored at the posterior tibial artery or dorsalis pedis artery.
KEY POINTS: NONINVASIVE VASCULAR DIAGNOSTIC LABORATORY
1. Duplex ultrasound has a sensitivity of 97% in detecting carotid artery disease and an accuracy of 95% in correctly classifying carotid stenoses as > 50% reduction in diameter.
2. The primary test for diagnosis of lower extremity ischemia is the ankle branchial index.
3. The noninvasive test used to diagnose acute DVT is duplex ultrasound.
12. What is gained by measuring pressures at limb levels other than the ankle?
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Segmental limb pressure (SLP) measurements, performed at the upper thigh, lower thigh, calf, and ankle, localize the arterial segment(s) involved in peripheral arterial occlusive disease.
13. What tests are used for assessing peripheral artery disease in diabetic patients who may have incompressible arteries caused by medial calcification?
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Pulse volume recording (PVR) is a pneumoplethysmographic technique that tracks the limb volume changes over the cardiac cycle. It measures the segmental pressure changes with pneumatic cuffs as a function of the limb volume changes. The relative PVR amplitudes identify the presence of peripheral artery disease and localize the arterial segment involved. The PVR is unaffected by medial calcification. Great-toe pressure also may be used to diagnose and assess disease severity in diabetic patients because medial calcification rarely affects the digital arteries.
14. How should the patient with suspected intermittent claudication be evaluated?
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The patient first should be evaluated by obtaining ABIs or segmental limb pressures at rest. The patient with ischemia at rest does not normally need further evaluation. The patient with mild arterial insufficiency at rest or even normal resting pressures should perform an exercise stress test (treadmill walking using either fixed or variable load protocols) followed by ABIs. The distance that the patient is able to walk allows assessment of functional disability, and the postexercise reduction in ankle pressure, or lack thereof, allows assessment of whether the disability is caused by arterial insufficiency rather than musculoskeletal or neurologic pain.
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Abernathy’s Surgical Secrets, Updated Edition (Book w / Student Consult)
Author / s: Harken Alden H., Abernathy Charles, Moore Ernest Eugene
Year: 2004
Pages: 473
Publishers: Elsevier Mosby; 5th Bk & Acc edition
ISBN: 0323034160
