From the Guidelines
The best diagnostic tests for intermittent claudication due to peripheral arterial disease (PAD) are noninvasive hemodynamic tests such as the ankle-brachial index (ABI), toe-brachial index, segmental pressures, and pulse volume recordings, followed by duplex ultrasound, computed tomography angiography (CTA), or magnetic resonance angiography (MRA) if revascularization is being considered.
Diagnostic Approach
- The initial diagnosis of PAD is typically made using noninvasive hemodynamic tests, which are considered the first line of diagnosis 1.
- The ankle-brachial index (ABI) is a reliable marker of PAD, with an ABI < 0.9 indicating ≥50% stenosis between the aorta and the distal leg arteries 1.
- If the results of noninvasive hemodynamic tests are inconclusive, duplex ultrasound, CTA, or MRA may be considered to establish the diagnosis of PAD and determine the severity of disease 2, 3.
Imaging Modalities
- Duplex ultrasound is a technologist-dependent modality with good sensitivity and specificity for detecting PAD stenotic and/or occlusive lesions, but has limited spatial resolution compared to CTA and MRA 4.
- CTA provides high spatial resolution but is limited by the need for iodinated contrast and radiation exposure 4.
- MRA provides high spatial resolution and can visualize infrapopliteal and pedal vessels, but certain formulations of gadolinium-containing contrast agents are contraindicated in patients with severe renal dysfunction 4.
Revascularization Planning
- If revascularization is being considered, duplex ultrasound, CTA, MRA, or catheter angiography can be used to assess anatomy and severity of disease and determine potential revascularization strategy 2.
- Catheter angiography remains the gold standard for imaging the peripheral vasculature and allows for dynamic depiction of the arteries, but is associated with potential risks such as radiation exposure and contrast nephropathy 3.
From the Research
Diagnostic Tests for Intermittent Claudication
The diagnosis of intermittent claudication due to peripheral arterial disease (PAD) can be made using a combination of clinical history, physical examination, and non-invasive tests. The following are some of the best diagnostic tests for intermittent claudication:
- Ankle-brachial index (ABI): This is the most commonly used test for screening and diagnostic purposes 5, 6. An ABI of 0.9 or less is believed to be associated with 50% or greater vessel stenosis 6.
- Comprehensive history and physical examination: This is paramount for initial diagnosis and to differentiate between claudication secondary to vascular disease vs. neurogenic causes 5.
- Palpation of peripheral pulses: This is the single most important part of the physical examination to confirm a diagnosis of intermittent claudication 6.
- Walking Impairment Questionnaire (WIQ): This is a qualitative measure that best describes the ambulatory limitations in patients with symptomatic peripheral arterial disease 7.
- Claudication distances: Initial and absolute claudication distances are measures that correlate well with the ambulatory limitation of patients with symptomatic peripheral arterial disease 7.
Non-Invasive Tests
Non-invasive tests such as the ankle-brachial index (ABI) are useful in diagnosing intermittent claudication. The ABI is a simple, non-invasive test that can be performed in a clinical setting 5, 6. Other non-invasive tests such as duplex ultrasound and computed tomography angiography (CTA) may also be used to diagnose PAD, but are not as commonly used for intermittent claudication 8.
Clinical Evaluation
A comprehensive clinical evaluation is essential in diagnosing intermittent claudication. This includes a thorough medical history, physical examination, and non-invasive tests. The clinical evaluation should aim to identify the underlying cause of the claudication, as well as assess the severity of the disease 9, 5. The WHO/Rose Questionnaire and the Edinburgh Questionnaire have been used widely to diagnose intermittent claudication, but they have a low sensitivity and therefore underestimate the true prevalence of the condition 6.