Ankle-Brachial Index - Essay Example

"Ankle-Brachial Index" is a worthy example of a paper on diagnostic tests.
The ankle-brachial index (ABI) test is a fast, painless, non-invasive method of identifying a person’s likelihood of developing peripheral artery disease (PAD). PAD is a disorder wherein the arms’ or legs’ arteries are clogged or constricted. Individuals with this disorder are highly susceptible to leg pain, stroke, heart attack and poor circulation (WOCNS, 2012). ABI test is performed by determining blood pressure at the arm and in the ankle in a resting position. Some patients perform an exercise test as well, wherein blood pressure is measured at the arm and in the ankle after several minutes of treading on a treadmill (Bozkurt, Tasci, Tabak, Gumus, & Kaplan, 2011). Within the primary care environment, an ABI test is beneficial in both contexts: first, in an asymptomatic individual, to evaluate the vascular susceptibility to PAD; and, second, in asymptomatic individual, to make a diagnosis of PAD. In trauma or emergency situations, an ABI test is beneficial for the assessment of an individual who is at higher risk for lower-extremity arterial damage (WOCNS, 2012; Bozkurt et al., 2011).

Indications for an ABI test are as follows (WOCNS, 2012, S23-S24): in combined arterial/venous disorder, lower levels of compression are recommended; compression must be prevented and the patient must be advised to consult a vascular specialist for surgical assessment or additional tests if the ABI is lower than 0.5; high, continuous compression is not advised for patients with ABI lower than 0.8; establish sufficient flow of arterial blood in lower extremities before wound debridement, or compression therapy; older age with a history of diabetes and smoking; 70 and above years of age; recurrent claudication (i.e. fatigue or pain in the legs that happens when walking); determine the diagnosis of the arterial disorder in individuals with suspected lower extremity arterial disease (LEAD), and dismiss LEAD in individuals with a lower extremity injury.

The important results to look for in an ABI test are classified in the following: no blockage; borderline; mild blockage; moderate blockage; severe blockage; and rigid arteries. The American College of Cardiology and the American Heart Association proposes a normal ABI ranges from 1.0-1.4, a borderline ABI ranges from 0.91-0.99, and an abnormal ABI lower than 0.9 (Bozkurt et al., 2011). These ranges change for exercise ABI test results. As previously stated, the ABI result can establish the diagnosis of PAD. A lower ABI implies probable PAD. A minor decrease in ABI result with exercise, although the patient has a normal ABI when resting, implies that s/he possibly suffers from PAD (Bozkurt et al., 2011; WOCNS, 2012).       

A normal ABI at rest is 1.0 to 1.4. This indicates that the person’s blood pressure at his/her ankle is higher than or the same as the pressure at his/her arm, and indicates that s/he do not suffer from major blockage or tightening of blood flow (Coke, 2010). On the other hand, abnormal results for ABI at rest are lower than 0.9 or higher than 1.40. If the ABI ranges from 0.91 to 1.00, it is classified as borderline abnormal. Abnormal results may imply a patient has a greater risk for constricted arteries in other body parts (Coke, 2010; Bozkurt et al., 2011). This can elevate the patient’s susceptibility to a stroke or heart attack.