title: The dicrotic notch as alternative time-reference point to measure local pulse wave velocity in the carotid artery by means of ultrasonography.
abstract: OBJECTIVE
  Increased arterial stiffness is associated with cardiovascular disease. Its applicability in individual patient management, however, is limited due to lack of reliable methods. We developed a method to measure arterial stiffness by means of local pulse wave velocity (PWV), using multiple M-mode ultrasound and the dicrotic notch (PWVdn) rather than the systolic foot (PWVsf) as time-reference point.
  
  
  METHODS
  Systolic foot and dicrotic notch were determined in 14 simultaneously recorded distension waveforms obtained in young and older participants (mean age 26 and 59 years). Linear regression was performed on echo-line position and time-reference point, resulting in a local PWV estimate, either PWVsf or PWVdn.
  
  
  RESULTS
  PWVdn, at about mean arterial pressure, had a better intra-individual variability (0.6 m/s) than PWVsf (1.1 m/s). The expected difference in stiffness between the two age categories was identified by PWVdn (P < 0.0001), but not by PWVsf. Moreover, in contrast to PWVsf, PWVdn showed a significant correlation with relative distension (r = 0.56) and the local distensibility coefficient (r = 0.52).
  
  
  CONCLUSIONS
  PWVdn is a noninvasive and suitable measure of arterial stiffness: it has a good reproducibility, discriminates well between age groups, and correlates with local distensibility. PWVdn does not require additional assessment of distance or local pulse pressure. Furthermore, PWVdn is measured locally, at near-mean arterial pressure, thereby better reflecting the effective arterial stiffness, which determines the load the left ventricle is subjected to as it ejects blood.
authors: Department of Biomedical Engineering/Biophysics, Maastricht University, Maastricht 6200 MD, The Netherlands.
authors: Evelien
authors: E
authors: Hermeling
authors: Koen D
authors: KD
authors: Reesink
authors: Liselotte M
authors: LM
authors: Kornmann
authors: Robert S
authors: RS
authors: Reneman
authors: Arnold Pg
authors: AP
authors: Hoeks
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001783:Blood Flow Velocity / Q000502:physiology*; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000502:physiology; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D006973:Hypertension / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008875:Middle Aged; D011673:Pulsatile Flow / Q000502:physiology*; D012015:Reference Standards; D015203:Reproducibility of Results; D014463:Ultrasonography / Q000379:methods / Q000592:standards*; D055815:Young Adult