American Board of Internal Medicine (ABIM) Certification Practice Exam

If a patient has claudication and a borderline ABI, what test is recommended?

1. Magnetic resonance angiography

2. Exercise ankle-brachial index testing

3. Stress echocardiogram

4. Treadmill functional capacity test

The correct answer is: Exercise ankle-brachial index testing

The recommended test for a patient with claudication and a borderline ankle-brachial index (ABI) is exercise ankle-brachial index testing. This test is specifically designed to assess the severity of peripheral artery disease (PAD) more precisely when initial resting ABI results are inconclusive or considered borderline. When a patient presents with claudication—pain in the legs during exertion due to inadequate blood flow—it's important to confirm the diagnosis of PAD. The ABI is a non-invasive test that compares the blood pressure in the patient's ankle with the blood pressure in the arm. A borderline ABI can be ambiguous, and exercise testing can help clarify the presence of significant vascular disease because symptoms, and subsequently blood flow, may become more apparent with physical activity. During exercise ankle-brachial index testing, the patient performs an activity, usually walking on a treadmill, which can induce symptoms of claudication, allowing for a more accurate assessment of blood flow changes and enhancing the reliability of ABI results. If claudication occurs, measuring the ABI during and after exercise helps determine if there is a significant difference suggesting PAD. Other tests mentioned, such as magnetic resonance angiography or a stress echocardiogram, are more invasive or focused on different aspects of