title: Simultaneous Noninvasive Assessment of Systemic and Coronary Endothelial Function.
abstract: BACKGROUND
  Normal endothelial function is a measure of vascular health and dysfunction is a predictor of coronary events. Nitric oxide-mediated coronary artery endothelial function, as assessed by vasomotor reactivity during isometric handgrip exercise (IHE), was recently quantified noninvasively with magnetic resonance imaging (MRI). Because the internal mammary artery (IMA) is often visualized during coronary MRI, we propose the strategy of simultaneously assessing systemic and coronary endothelial function noninvasively by MRI during IHE.
  
  
  RESULTS
  Changes in cross-sectional area and blood flow in the right coronary artery and the IMA in 25 patients with coronary artery disease and 26 healthy subjects during IHE were assessed using 3T MRI. In 8 healthy subjects, a nitric oxide synthase inhibitor was infused to evaluate the role of nitric oxide in the IMA-IHE response. Interobserver IMA-IHE reproducibility was good for cross-sectional area (R=0.91) and blood flow (R=0.91). In healthy subjects, cross-sectional area and blood flow of the IMA increased during IHE, and these responses were significantly attenuated by monomethyl-l-arginine (P<0.01 versus placebo). In patients with coronary artery disease, the right coronary artery did not dilate with IHE, and dilation of the IMA was less than that of the healthy subjects (P=0.01). The blood flow responses of both the right coronary artery and IMA to IHE were also significantly reduced in patients with coronary artery disease.
  
  
  CONCLUSIONS
  MRI-detected IMA responses to IHE primarily reflect nitric oxide-dependent endothelial function and are reproducible and reduced in patients with coronary artery disease. Endothelial function in both coronary and systemic (IMA) arteries can now be measured noninvasively with the same imaging technique and promises novel insights into systemic and local factors affecting vascular health.
authors.affiliation: Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD.|Critical Care Medicine Department, National Institutes of Health, Bethesda, MD.
authors.forename: Micaela
authors.initials: M
authors.lastname: Iantorno
authors.affiliation: Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD.
authors.forename: Allison G
authors.initials: AG
authors.lastname: Hays
authors.affiliation: Department of Radiology, Division of Magnetic Resonance Research, Johns Hopkins University, Baltimore, MD.
authors.forename: Michael
authors.initials: M
authors.lastname: Schär
authors.affiliation: Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD.
authors.forename: Rupa
authors.initials: R
authors.lastname: Krishnaswamy
authors.affiliation: Department of Radiology, Division of Magnetic Resonance Research, Johns Hopkins University, Baltimore, MD.|Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD.
authors.forename: Sahar
authors.initials: S
authors.lastname: Soleimanifard
authors.affiliation: Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD.
authors.forename: Angela
authors.initials: A
authors.lastname: Steinberg
authors.affiliation: Department of Radiology, Division of Magnetic Resonance Research, Johns Hopkins University, Baltimore, MD.|Department of Radiology, Centre Hospitalier Universitaire Vaudois, Center for Biomedical Imaging (CIBM) and University of Lausanne, Lausanne, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Stuber
authors.affiliation: Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD.
authors.forename: Gary
authors.initials: G
authors.lastname: Gerstenblith
authors.affiliation: Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD.|Department of Radiology, Division of Magnetic Resonance Research, Johns Hopkins University, Baltimore, MD.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Weiss
mesh_terms: D000328:Adult; D050197:Atherosclerosis / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology; D001783:Blood Flow Velocity; D016022:Case-Control Studies; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology*; D004791:Enzyme Inhibitors / Q000008:administration & dosage; D005260:Female; D018737:Hand Strength; D006801:Humans; D007262:Infusions, Intravenous; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008323:Mammary Arteries / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology*; D008875:Middle Aged; D009119:Muscle Contraction; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013997:Time Factors; D014664:Vasodilation / Q000187:drug effects
chemical_list: D004791:Enzyme Inhibitors; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase
keywords: atherosclerosis; coronary artery disease; endothelium; magnetic resonance imaging; vasodilation