Treadmill testing in the assessment of peripheral arterial disease.

A treadmill exercise test is used in many vascular laboratories to measure the claudication time and the total walking time of patients with intermittent claudication. Three hundred and nine consecutive outpatients in the peripheral arterial disease clinic were assessed on the treadmill. Fifty-nine were unable to walk on it at all, and of the remaining 250 patients, 68 (27%) could manage five minutes of treadmill exercise, and 87 (35%) patients stopped for reasons other than intermittent claudication. Only 95 (38%) stopped walking within five minutes as a result of intermittent claudication. Fifty of these 95 patients were retested approximately 10 days later and the mean change from day 1 to day 2 in the claudication time and in the total walking time was calculated to establish the normal range. From these results, if a treadmill is to be used to infer any improvement, we calculate that the claudication time must increase by at least 63 seconds and the total walking time by 93 seconds. Treadmill testing for the assessment of symptoms, if it is used at all, should be used in conjunction with objective methods of assessment.