Diagnosis value of exercise treadmill testing (bruce protocol) in assessing early atherosclerotic lesions of lower extremity / 中华老年医学杂志

ABSTRACT

Objective To assess the value of exercise treadmill testing (bruce protocol) in diagnosing early atherosclerotic lesions of the lower limb. Methods Between March and September 2008, 173 outpatients with high risks of peripheral arterial disease (PAD) were enrolled randomly from the cardiology clinic of Chinese PLA General Hospital. The patients were subjected to exercise treadmill testing (Bruce protocol) and ankle-brachial index (ABI) determination, as well as lower limb artery ultrasonography within one week. Using ultrasonic findings as diagnostic criteria, the diagnostic sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of exercise treadmill testing for early atherosclerotic lesions of the lower limb were analyzed, and the diagnostic value of exercise treadmill testing was assessed using the ROC curve. Results After exercise, ABI decrement (R value) increased in subjects with high risks for PAD with atherosclerotic lesions of the lower limb aggravating. Using the presence of large atherosclerotic plaques (area > 20 mm2 ), atherosclerotic plaques and atherosclerotic lesions in lower limb arteries as positive diagnostic criteria, the area under curve of ROC was 0. 80 (95% CI 0.72-0.88), 0.78 (95% CI 0.71-0.85) and 0. 60 (95% CI 0.44-0.76), respectively. Using the presence of large atherosclerotic plaques in lower extremities as positive diagnosis, R value was 0.80, with a sensitivity of 54. 0%, a specificity of 96. 7%, a LR+ of 16. 4, and a LR- of 0. 58, meanwhile, R value was 0. 85, with a sensitivity of 70.0%, a specificity of 91.9%, a LR + of 8.64, and a LR- of 0.33. Conclusions Exercise treadmill testing (Bruce protocol) in combination with ABI determination is a safe, accurate, objective tool for detecting early atherosclerotic lesions of the lower limb. Immediately after exercise, 0.85 is the cut-off R value appropriate for diagnosing large atherosclerotic plaques of the lower limb (area > 20 mm2).