title: Influence of the central-to-peripheral arterial stiffness gradient on the timing and amplitude of wave reflections.
abstract: In individuals with compliant aortas, peripheral muscular artery stiffness exceeds central elastic artery stiffness. With aging, central stiffness increases with little change in peripheral stiffness, resulting in a reversal of the normal stiffness gradient. This reversal may reduce the wave reflection amplitude due to the movement of the major 'effective' reflection site further from the heart. To test this phenomenon, we investigated the relationship among arterial stiffness gradients (normal and reversed), wave reflection amplitude and reflection site distance. Subjects aged ⩾50 years were recruited from the Anglo-Cardiff Collaborative Trial. Central stiffness was assessed by carotid-femoral pulse wave velocity (cfPWV). In Study 1, peripheral PWV was also measured in the arm (carotid-radial pulse wave velocity) and, in Study 2, in the leg (femoral-dorsalis pedis). Reflection site distance was calculated from cfPWV and the reflected wave Tr. Subjects were dichotomized into those with a normal stiffness gradient (peripheral >central PWV) or a reversed gradient (peripheral <central PWV). In Study 1, the reflection site distance was greater in subjects with a reversed gradient (P<0.01), whereas time-to-reflection was lower (P<0.001). Both the augmentation pressure (P<0.001) and augmentation index (P<0.05) were greater in subjects with a reversed gradient. In Study 2, the augmentation pressure, augmentation index and reflection site distance were greater in subjects with a reversed stiffness gradient (P<0.01, P<0.05 and P<0.01, respectively), and time-to-reflection was not different between groups. A reversed arterial stiffness gradient is associated with an increased reflection site distance, and a paradoxical increase in reflected wave amplitude and augmentation index.
authors.affiliation: Division of Experimental Medicine and Immunotherapeutics, Department of Medicine, University of Cambridge, Cambridge, UK.
authors.forename: Stacey S
authors.initials: SS
authors.lastname: Hickson
authors.affiliation: Division of Cardiovascular Medicine, Department of Medicine, University of Florida, Gainesville, FL, USA.
authors.forename: Wilmer W
authors.initials: WW
authors.lastname: Nichols
authors.affiliation: Division of Experimental Medicine and Immunotherapeutics, Department of Medicine, University of Cambridge, Cambridge, UK.
authors.lastname: Yasmin
authors.affiliation: Department of Biomedical Sciences, School of Health Sciences, Cardiff Metropolitan University, Cardiff, UK.
authors.forename: Barry J
authors.initials: BJ
authors.lastname: McDonnell
authors.affiliation: Department of Cardiology, Wales Heart Research Institute, Cardiff University, Cardiff, UK.
authors.forename: John R
authors.initials: JR
authors.lastname: Cockcroft
authors.affiliation: Division of Experimental Medicine and Immunotherapeutics, Department of Medicine, University of Cambridge, Cambridge, UK.
authors.forename: Ian B
authors.initials: IB
authors.lastname: Wilkinson
authors.affiliation: Division of Experimental Medicine and Immunotherapeutics, Department of Medicine, University of Cambridge, Cambridge, UK.
authors.forename: Carmel M
authors.initials: CM
authors.lastname: McEniery
mesh_terms: D000368:Aged; D001011:Aorta / Q000502:physiology*; D001132:Arm / Q000098:blood supply; D001794:Blood Pressure / Q000502:physiology; D002339:Carotid Arteries / Q000502:physiology*; D005260:Female; D005263:Femoral Artery / Q000502:physiology*; D006801:Humans; D007866:Leg / Q000098:blood supply; D008297:Male; D008875:Middle Aged; D011673:Pulsatile Flow / Q000502:physiology; D063177:Pulse Wave Analysis; D059289:Vascular Stiffness / Q000502:physiology*