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International Journal of Vascular Medicine
Volume 2012, Article ID 274381, 6 pages
http://dx.doi.org/10.1155/2012/274381
Clinical Study

The Influence of Endothelial Function and Myocardial Ischemia on Peak Oxygen Consumption in Patients with Coronary Artery Disease

1Montreal Behavioural Medicine Centre, Hôpital du Sacré-Coeur de Montréal, A University of Montreal Affiliated Hospital, Montréal, QC, Canada H4J 1C5
2Department of Exercise Science, Concordia University, Montreal, QC, Canada H4B 1R6
3Research Centre, Hôpital du Sacré-Coeur de Montréal, A University of Montreal Affiliated Hospital, Montréal, QC, Canada H4J 1C5
4Research Centre, Montreal Heart Institute, A University of Montreal Affiliated Hospital, Montréal, QC, Canada H1T 1C8
5Department of Psychiatry and Behavioral Science, Duke University Medical Center, Durham, NC 27708, USA
6Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
7Department of Psychology, Université du Québec à Montréal, Montréal, QC, Canada H3C 3P8

Received 11 June 2012; Revised 16 August 2012; Accepted 8 September 2012

Academic Editor: Linda Pescatello

Copyright © 2012 Simon L. Bacon et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Impaired endothelial function has been shown to limit exercise in coronary artery disease (CAD) patients and has been implicated in myocardial ischemia. However, the association of endothelial function and ischemia on peak exercise oxygen consumption (VO2) has not been previously reported. A total of 116 CAD patients underwent standard exercise stress testing, during which VO2 was measured. On a separate day, endothelial-dependent and -independent function were assessed by ultrasound using flow-mediated arterial vasodilation (FMD) and sublingual glyceryl trinitrate administration (GTNMD) of the brachial artery. Patients with exercise-induced myocardial ischemia had lower FMD than nonischemic patients ( versus , ), but there was no difference in GTNMD ( versus , ). Analyses revealed that both FMD ( ) and GTNMD ( ) were related to peak VO2. However, neither the presence of ischemia ( ) nor the interaction of ischemia with FMD ( ) and GTNMD ( ) was related to peak VO2. These data suggest that poor endothelial function, potentially via impaired NO production and smooth muscle dysfunction, may be an important determinant of exercise capacity in patients with CAD, independent of myocardial ischemia.