OBJECTIVES: We sought to analyze diameter changes of conduit arteries in response to whole-body exercise and hypothesized that this response might be endothelium-dependent and, therefore, impaired in smokers. BACKGROUND: Hyperemia and coincident vasodilation are pivotal mechanisms for meeting the increased metabolic demands of active muscle tissue during physical exercise, but studies in humans are sparse. METHODS: We studied diameter and blood flow of the femoral and brachial arteries in response to a submaximal bicycle exercise test in 10 nonsmoking and 8 smoking healthy male subjects. During an exercise period of 40 min the investigated conduit arteries were periodically scanned in longitudinal sections by high-resolution ultrasound. In the same subjects flow-mediated dilation (FMD) of the brachial artery was recorded by inducing an ischemia through a forearm-occluding cuff. RESULTS: In response to exercise the diameter of the femoral artery significantly increased in both nonsmokers and smokers, with a diminished response in smokers (9.2 +/- 1.9% vs. 4.8 +/- 1.6%, p < 0.001). Flow-mediated dilation of the brachial artery induced by forearm occlusion was also reduced in smoking subjects, revealing a strong correlation between these different methods of FMD (exercise vs. forearm ischemia) (r = 0.88, p < 0.001). In contrast, blood flow increase of the femoral artery was similar in nonsmoking and smoking subjects (392 +/- 77% vs. 382 +/- 109%, p = NS). CONCLUSIONS: Conduit arteries react with a flow-mediated dilation in response to whole-body exercise. The impairment of this vasodilation observed in smokers was strongly related to a decrease of endothelium-dependent dilation induced by forearm ischemia, indicating that endothelial dysfunction represents the underlying mechanism.
OBJECTIVES: We sought to analyze diameter changes of conduit arteries in response to whole-body exercise and hypothesized that this response might be endothelium-dependent and, therefore, impaired in smokers. BACKGROUND:Hyperemia and coincident vasodilation are pivotal mechanisms for meeting the increased metabolic demands of active muscle tissue during physical exercise, but studies in humans are sparse. METHODS: We studied diameter and blood flow of the femoral and brachial arteries in response to a submaximal bicycle exercise test in 10 nonsmoking and 8 smoking healthy male subjects. During an exercise period of 40 min the investigated conduit arteries were periodically scanned in longitudinal sections by high-resolution ultrasound. In the same subjects flow-mediated dilation (FMD) of the brachial artery was recorded by inducing an ischemia through a forearm-occluding cuff. RESULTS: In response to exercise the diameter of the femoral artery significantly increased in both nonsmokers and smokers, with a diminished response in smokers (9.2 +/- 1.9% vs. 4.8 +/- 1.6%, p < 0.001). Flow-mediated dilation of the brachial artery induced by forearm occlusion was also reduced in smoking subjects, revealing a strong correlation between these different methods of FMD (exercise vs. forearm ischemia) (r = 0.88, p < 0.001). In contrast, blood flow increase of the femoral artery was similar in nonsmoking and smoking subjects (392 +/- 77% vs. 382 +/- 109%, p = NS). CONCLUSIONS: Conduit arteries react with a flow-mediated dilation in response to whole-body exercise. The impairment of this vasodilation observed in smokers was strongly related to a decrease of endothelium-dependent dilation induced by forearm ischemia, indicating that endothelial dysfunction represents the underlying mechanism.
Authors: Georgios I Papaioannou; Christos Kasapis; Richard L Seip; Neil J Grey; Deborah Katten; Frans J Th Wackers; Silvio E Inzucchi; Samuel Engel; Amy Taylor; Lawrence H Young; Deborah A Chyun; Janice A Davey; Ami E Iskandrian; Robert E Ratner; Evelyn C Robinson; Stella Carolan; Gary V Heller Journal: J Nucl Cardiol Date: 2006 May-Jun Impact factor: 5.952