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School of Medicine
Non-Invasive Flow Studies
Atherosclerosis in the leg arteries can decrease the blood flow and thus the oxygen supply to the muscles, causing pain when walking, or "claudication". The most common cause of claudication is peripheral arterial disease (PAD).
If you have symptoms such as discomfort in your legs with walking or an ulcer on your foot, your physician may order Non-Invasive Flow Studies (NIFS). NIFS include segmental pressures and pulse volume recordings, both of which provide information about the arterial circulation. Blood pressure cuffs are inflated on the arms, thighs, calves, ankles, and feet. The study also includes the measurement of the ABI (ankle-brachial index). A normal ABI is between 0.90 and 1.3.
If your ABI is less than 0.90, then your test result is not normal and you most likely have peripheral arterial disease (PAD). If your ABI is more than 1.3, then the vessel may be calcified and the number is not valid. If your ABI is normal or borderline at rest, you may be asked to walk on the treadmill to see if your ABI drops with exercise.
Early diagnosis of PAD is important to insure proper treatment and to prevent related cardiovascular complications such as heart attack and stroke. If you have been told that you need your ABI checked or that you are at risk for PAD, please call the Johns Hopkins Center for Vascular Medicine at 410-616-7225 or the Vascular Surgery Lab at 410-955-5165 to schedule an appointment for NIFS. No special preparation is needed prior to the test.