title: Effects of age and smoking on endothelial function assessed by quantitative cardiovascular magnetic resonance in the peripheral and central vasculature.
abstract: BACKGROUND
  Both age and smoking promote endothelial dysfunction and impair vascular reactivity. Here, we tested this hypothesis by quantifying new cardiovascular magnetic resonance (CMR)-based biomarkers in smokers and nonsmokers.
  
  
  METHODS
  Study population: young non-smokers (YNS: N = 45, mean age = 30.2 ± 0.7 years), young smokers (YS: N = 39 mean age 32.1 ± 0.7 years), older non-smokers (ONS: N = 45, mean age = 57.8 ± 0.6 years), and older smokers (OS: N = 40, mean age = 56.3 ± 0.6 years), all without overt cardiovascular disease. Vascular reactivity was evaluated following cuff-induced hyperemia via time-resolved blood flow velocity and oxygenation (SvO2) in the femoral artery and vein, respectively. SvO2 dynamics yielded washout time (time to minimum SvO2), resaturation rate (upslope) and maximum change from baseline (overshoot). Arterial parameters included pulse ratio (PR), hyperemic index (HI) and duration of hyperemia (TFF). Pulse-wave velocity (PWV) was assessed in aortic arch, thoracoabdominal aorta and iliofemoral arteries. Ultrasound-based carotid intimal-medial thickness (IMT) and brachial flow-mediated dilation were measured for comparison.
  
  
  RESULTS
  Age and smoking status were independent for all parameters. Smokers had reduced upslope (-28.4%, P < 0.001), increased washout time (+15.3%, P < 0.01), and reduced HI (-19.5%, P < 0.01). Among non-smokers, older subjects had lower upslope (-22.7%, P < 0.01) and overshoot (-29.4%, P < 0.01), elevated baseline pulse ratio (+14.9%, P < 0.01), central and peripheral PWV (all P < 0.05). Relative to YNS, YS had lower upslope (-23.6%, P < 0.01) and longer washout time (13.5%, P < 0.05). Relative to ONS, OS had lower upslope (-33.0%, P < 0.01). IMT was greater in ONS than in YNS (+45.6%, P < 0.001), and also in YS compared to YNS (+14.7%, P < 0.05).
  
  
  CONCLUSIONS
  Results suggest CMR biomarkers of endothelial function to be sensitive to age and smoking independent of each other.
authors.affiliation: Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA, 19104, USA. langhamc@mail.med.upenn.edu.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Langham
authors.affiliation: Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA, 19104, USA. zhouyong@mail.med.upenn.edu.
authors.forename: Yongxia
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA, 19104, USA. enchirico@gmail.com.
authors.forename: Erica N
authors.initials: EN
authors.lastname: Chirico
authors.affiliation: Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA, 19104, USA. jeremy.magland@uphs.upenn.edu.
authors.forename: Jeremy F
authors.initials: JF
authors.lastname: Magland
authors.affiliation: Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA, 19104, USA. sehgalc@uphs.upenn.edu.
authors.forename: Chandra M
authors.initials: CM
authors.lastname: Sehgal
authors.affiliation: Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA, 19104, USA. eenglund@mail.med.upenn.edu.
authors.forename: Erin K
authors.initials: EK
authors.lastname: Englund
authors.affiliation: Department of Medicine, University of Pennsylvania Medical Center, Philadelphia, PA, USA. mohlere@uphs.upenn.edu.
authors.forename: Emile R
authors.initials: ER
authors.lastname: Mohler
authors.affiliation: Department of Biostatistics and Epidemiology, University of Pennsylvania Medical Center, Philadelphia, PA, USA. wguo@mail.med.upenn.edu.
authors.forename: Wensheng
authors.initials: W
authors.lastname: Guo
authors.affiliation: Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA, 19104, USA. sulimanb@mun.ca.
authors.forename: Suliman
authors.initials: S
authors.lastname: Barhoum
authors.affiliation: Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA, 19104, USA. Wehrli@mail.med.upenn.edu.
authors.forename: Felix W
authors.initials: FW
authors.lastname: Wehrli
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001011:Aorta / Q000503:physiopathology*; D001783:Blood Flow Velocity; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging / Q000503:physiopathology; D059168:Carotid Intima-Media Thickness; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D005263:Femoral Artery / Q000503:physiopathology*; D005268:Femoral Vein / Q000503:physiopathology*; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology; D007083:Iliac Artery / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D063177:Pulse Wave Analysis; D012039:Regional Blood Flow; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D018608:Ultrasonography, Doppler; D014664:Vasodilation