Treadmill exercise testing
The most common symptom of peripheral artery disease (PAD) is intermittent claudication (IC). Muscles that have sufficient blood-flow under resting conditions may not have sufficient circulation when exercise increases the muscles’ demand for oxygenated blood. As a result, patients with claudication experience pain, aching or fatigue in their lower limb muscles when they walk
The ankle/brachial index (ABI) is an objective measurement of lower-extremity arterial perfusion. The ABI is the ratio of the arterial blood pressure at the ankle divided by the arm blood pressure. An ABI less than 0.90 is good evidence for the diagnosis of PAD.
Treadmill exercise testing and post-exercise measurement of ankle/brachial indices may be used in addition to resting measurements of lower-extremity arterial pressures and pulse volume recordings. In patients with lower-limb pain, treadmill testing can confirm or exclude PAD as the likely cause. The ankle pressure and ABI drops after exercise in patients with intermittent claudication due to PAD.
In addition to evaluating the effect of exercise on the ankle-level blood pressure, treadmill exercise testing also offers a means to characterize the functional impact of claudication symptoms. The distance walked before the onset of symptoms (pain-free walking distance) and the maximum distance that can be walked can be measured using a standardized speed and grade on the treadmill. These values establish a baseline for comparison, allowing objective assessment of change in walking performance with medical therapy or interventions.
No special preparation is required. Comfortable clothes and walking shoes should be worn. A complete study usually takes about 30 minutes. Treadmill testing may be inappropriate for people who need assistance to walk or who are limited by other medical conditions.
Evaluation by a specialist in the Division of Vascular Surgery will generally be recommended if the diagnoses of PAD and intermittent claudication are confirmed. Further evaluation or treatment may be recommended.
See also:
Diseases, conditions and their treatments: Claudication
Diseases, conditions and their treatments: Critical limb ischemia
Diseases, conditions and their treatments: Peripheral artery disease (PAD)
Vascular Laboratory exams: Bypass graft evaluation
Vascular Laboratory exams: Lower extremity physiologic testing
Vascular Laboratory exams: Peripheral arterial duplex scanning
Vascular Laboratory exams: Vein mapping