title: The influence of endothelial function and myocardial ischemia on peak oxygen consumption in patients with coronary artery disease.
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 (VO(2)) has not been previously reported. A total of 116 CAD patients underwent standard exercise stress testing, during which VO(2) 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 (3.64 ± 0.57 versus 4.98 ± 0.36, P = .050), but there was no difference in GTNMD (14.11 ± 0.99 versus 15.47 ± 0.63, P = .249). Analyses revealed that both FMD (P = .006) and GTNMD (P = .019) were related to peak VO(2). However, neither the presence of ischemia (P = .860) nor the interaction of ischemia with FMD (P = .382) and GTNMD (P = .151) was related to peak VO(2). 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.
authors.affiliation: Montreal Behavioural Medicine Centre, Hôpital du Sacré-Coeur de Montréal, A University of Montreal Affiliated Hospital, Montréal, QC, Canada H4J 1C5 ; Department of Exercise Science, Concordia University, Montreal, QC, Canada H4B 1R6 ; Research Centre, Hôpital du Sacré-Coeur de Montréal, A University of Montreal Affiliated Hospital, Montréal, QC, Canada H4J 1C5 ; Research Centre, Montreal Heart Institute, A University of Montreal Affiliated Hospital, Montréal, QC, Canada H1T 1C8.
authors.forename: Simon L
authors.initials: SL
authors.lastname: Bacon
authors.forename: Andrew
authors.initials: A
authors.lastname: Sherwood
authors.forename: Alan
authors.initials: A
authors.lastname: Hinderliter
authors.forename: Annik
authors.initials: A
authors.lastname: Plourde
authors.forename: Lee
authors.initials: L
authors.lastname: Pierson
authors.forename: James A
authors.initials: JA
authors.lastname: Blumenthal