Vascular Tools

Chapter 32 Vascular Tools



Lino F. Miele, MD, MS, Alexander Uribe, MD



Section Editor’s Note


There is more to understanding a diagnostic study than simply reading the interpretation. The physician who understands the theory behind a test, how a test is performed technically and how it is interpreted and applied, will be best able to use the results of that test in the evaluation and treatment of the patient.


Accordingly, in the discussion of the first two Vascular Tools (Ankle-Brachial Index and Lower Extremity Arterial Duplex), a model is offered for consideration that can be used to organize background information on the tests that you commonly order. Given the constraints of space in this book, only two Tools will be covered in this manner; for the remaining Tools we give you “indications” only. You can find the more complete information on the Web site of this book.



Ankle-Brachial Index



Indication


Indications include a clinical history consistent with peripheral vascular disease, including claudication, rest pain or tissue loss, or a physical examination indicating decreased or absent pulses.



Theory


The ankle-brachial index (ABI) is a noninvasive measurement of the hemodynamic consequences of aortoiliac, femoropopliteal, and tibial occlusive disease.



Technical


The ankle systolic pressure is compared (indexed) with the brachial systolic pressure. A pneumatic cuff (blood pressure cuff) is wrapped around the ankle. Using a Doppler, flow is identified in the dorsalis pedis and posterior tibial arteries. With inflation of the cuff, blood flow is occluded. The ankle systolic pressure (PAnkle) in the dorsalis pedis and posterior tibial arteries is the pressure at which flow returns when the cuff is deflated. In a similar fashion, the right and left brachial artery systolic pressures are obtained. The ankle pressures are compared to the higher of the two brachial pressures (PBrachial):




image




Interpretation


The study provides an ABI for the dorsalis pedis and posterial tibial artery. Generally the higher of the two is considered to provide an estimate of flow to the ankle. Normally the ankle systolic blood pressure is equal to or higher than the brachial systolic pressure. The normal ABI is 1 to 1.2, and less than 0.9 is abnormal. Patients with claudication have ABIs from 0.5 to 0.8, whereas patients with rest pain have ABIs less than 0.3.



Application


The ABI should always be interpreted in the perspective of the patient’s clinical symptoms. Frequently a patient’s clinical symptoms can improve even though there may be no change in the ABI.



Additional Considerations


Diabetic patients can have circumferential calcification involving the media of midsized arteries, such as the superficial femoral, popliteal, and tibial arteries. The circumferential calcification prevents compression of the arteries, resulting in artifactual elevation of the ankle pressure and the ABI. See Sabiston 66, Becker 37.

Related posts:

  1. Pigmented Skin Lesion in a 58-Year-Old Female (Case 12)
  2. Professor’s Pearls: Pediatric Surgery
  3. Splenomegaly in a 40-Year-Old Female (Case 19)
  4. The Resident as Teacher: Facilitating Student Success

Stay updated, free articles. Join our Telegram channel
Tags:
Mar 20, 2017 | Posted by in GENERAL SURGERY | Comments Off on Vascular Tools

Full access? Get Clinical Tree
Get Clinical Tree app for offline access