title: Quantitative CMR markers of impaired vascular reactivity associated with age and peripheral artery disease.
abstract: BACKGROUND
  The aim of this study was to develop and evaluate an integrated CMR method incorporating dynamic oximetry, blood flow and pulse-wave velocimetry to assess vascular reactivity in patients with peripheral artery disease (PAD) and healthy controls.
  
  
  RESULTS
  The study population consisted of young healthy subjects (YH, 30 ± 7 yrs, N = 19),PAD (71 ± 9 yrs, N = 38), and older healthy controls (OHC, 68 ± 9 yrs, N = 43). Peripheral vascular reactivity was evaluated with two methods, time-resolved quantification of blood flow velocity and oxygenation level in the femoral artery and vein, respectively, performed simultaneously both at rest and hyperemia. Aortic stiffness was assessed via pulse-wave velocity. Oximetric data showed that compared to OHC, the time-course of the hemoglobin oxygen saturation in PAD patients had longer washout time (28.6 ± 1.2 vs 16.9 ± 1.1 s, p < 0.0001), reduced upslope (0.60 ± 0.1 vs 1.3 ± 0.08 HbO2/sec, p < 0.0001) and lower overshoot (8 ± 1.4 vs 14 ± 1.2 HbO2, p = 0.0064). PAD patients also had longer-lasting antegrade femoral artery flow during hyperemia (51 ± 2.1 vs 24 ± 1.8 s, p < 0.0001), and reduced peak-to-baseline flow rate (3.1 ± 0.5 vs 7.4 ± 0.4, p < 0.0001). Further, the pulsatility at rest was reduced (0.75 ± 0.32 vs 5.2 ± 0.3, p < 0.0001), and aortic PWV was elevated (10.2 ± 0.4 vs 8.1 ± 0.4 m/s, p = 0.0048).
  
  
  CONCLUSIONS
  The proposed CMR protocol quantifies multiple aspects of vascular reactivity and represents an initial step toward development of a potential tool for evaluating interventions, extrapolating clinical outcomes and predicting functional endpoints based on quantitative parameters.
authors: Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, PA 19104, USA.
authors: Michael C
authors: MC
authors: Langham
authors: Erin K
authors: EK
authors: Englund
authors: Emile R
authors: ER
authors: Mohler
authors: Cheng
authors: C
authors: Li
authors: Zachary B
authors: ZB
authors: Rodgers
authors: Thomas F
authors: TF
authors: Floyd
authors: Felix W
authors: FW
authors: Wehrli
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001013:Aorta, Thoracic / Q000503:physiopathology*; D015415:Biomarkers / Q000097:blood; D001783:Blood Flow Velocity; D016022:Case-Control Studies; D005263:Femoral Artery / Q000503:physiopathology*; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D010092:Oximetry; D010108:Oxyhemoglobins / Q000378:metabolism; D058729:Peripheral Arterial Disease / Q000097:blood / Q000175:diagnosis* / Q000503:physiopathology; D011237:Predictive Value of Tests; D063177:Pulse Wave Analysis; D012039:Regional Blood Flow; D013997:Time Factors; D059289:Vascular Stiffness; D055815:Young Adult
chemical_list: D015415:Biomarkers; D010108:Oxyhemoglobins
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