Episode 12 - Ankle-brachial Index

A patient is seen in an outpatient cardiac rehabilitation facility for complaints of claudication during exercise. The therapist assesses the patient’s ankle-brachial index as a part of the examination. Which ankle-brachial index value would be MOST consistent with complaints of claudication symptoms that only occur during fairly intense exercise?

1. 0.10
2. 0.40
3. 0.70
4. 1.10

Welcome back to the Scorebuilders’ Question and Answer Podcast! This podcast provides members of the Scorebuilders’ team with the opportunity to explore challenging multiple-choice examination questions with students actively preparing for the licensing examination. My name is Scott Giles and I will be your host for today’s journey.

Ready? Let’s go! 

A patient is seen in an outpatient cardiac rehabilitation facility for complaints of claudication during exercise. The therapist assesses the patient’s ankle-brachial index as a part of the examination. Which ankle-brachial index value would be MOST consistent with complaints of claudication symptoms that only occur during fairly intense exercise?

1. 0.10
2. 0.40
3. 0.70
4. 1.10

Wow! It’s great to encounter our old friend – ABI! Ankle-Brachial Index. The ABI is a measure of perfusion of the lower extremities.

ABI Measurement
Systolic blood pressures are measured in both brachial arteries and both tibialis posterior arteries with a sphygmomanometer and a handheld Doppler ultrasound device.

The ABI is calculated by dividing the higher of the two systolic blood pressure measurements in the ankles by the higher of the two systolic blood pressure measurements in the arms.

ABI Values
A normal ABI value is typically defined as falling between 1.0 and 1.4.

Normal: 1.0 – 1.4
Indicates no blockage. Values above 1.0 can be considered normal since pressure is normally higher in the ankle than in the arm. Values above 1.4 suggest a noncompressible calcified vessel

Mild Blockage: 0.8 – 0.99
Indicates the beginning of peripheral arterial disease

Moderate blockage: 0.4 – 0.79
Indicates moderate peripheral arterial disease

Severe blockage: less than 0.4
Indicates severe peripheral arterial disease

Let’s explore each of the options.

Option 1 - 0.10
An ABI value of 0.10 indicates that the patient has severe peripheral arterial disease. A patient with severe peripheral arterial disease would have pain both with activity and at rest (i.e., resting claudication). There may also be associated tissue necrosis secondary to poor perfusion to the lower extremities.

Option 2 - 0.40
An ABI value of 0.40 indicates that the patient has moderate to severe peripheral arterial disease. A patient with moderate to severe peripheral arterial disease would have pain both with activity and at rest and would be referred to a vascular specialist.

Option 3 - 0.70
An ABI value of 0.70 indicates that the patient has moderate peripheral arterial disease. A patient with moderate peripheral arterial disease would likely only have symptoms with physical activity. They would typically be referred to a vascular specialist.

If the patient’s ABI was indicative of only mild peripheral arterial disease (i.e., 0.80-0.99), treatment would be focused on risk factor management (e.g., smoking, diabetes, high cholesterol, high blood pressure, atherosclerosis). 

Option 4 - 1.10
An ABI value of 1.10 is considered normal. This patient would not have peripheral arterial disease and would not present with any claudication symptoms.

The correct answer is Option 3

Let’s explore the all student data:
4% of students selected Option 1, an ABI of 0.10
18% of students selected Option 2, an ABI of 0.40
64% of students selected Option 3, an ABI of 0.70, the correct response
14% of students selected Option 4, an ABI of 1.10

System Classification
This question is a Cardiovascular and Pulmonary Systems question which represents approximately 14% of all exam items.

Content Outline Classification
This question is a Physical Therapy Examination question which represents approximately 24% of all exam items.

Level Classification
This question is a Level 1 question since the question requires students to possess basic foundational academic knowledge. Remediation of Level 1 questions occurs through academic review of entry-level content using textbooks, review books, Basecamp, and flash cards.

Academic Focus Area
Looking to review related academic content? Page 430 from PTEXAM: The Complete Study Guide.

Bonus Thought
The ABI can be an effective diagnostic tool, but it’s also important to be aware of other signs of peripheral vascular disease. 

These include patient history and examination findings such as pain with walking, paraesthesia, paralysis, pulselessness (i.e., dorsalis pedis and posterior tibial arteries), and pallor of the distal extremities. Both paralysis and paraesthesia are often seen in the presence of very severe ischemia to the legs.

Thanks for joining us on the Scorebuilders Q and A podcast! See you next week!

Watch the video version of this Q&A episode on YouTube - https://youtu.be/f0OJVlcQ5uQ