title: Novel application of parameters in waveform contour analysis for assessing arterial stiffness in aged and atherosclerotic subjects.
abstract: OBJECTIVE
  Although contour analysis of pulse waves has been proposed as a non-invasive means in assessing arterial stiffness in atherosclerosis, accurate determination of the conventional parameters is usually precluded by distorted waveforms in the aged and atherosclerotic objects. We aimed at testing reliable indices in these patient populations.
  
  
  METHODS
  Digital volume pulse (DVP) curve was obtained from 428 subjects recruited from a health screening program at a single medical center from January 2007 to July 2008. Demographic data, blood pressure, and conventional parameters for contour analysis including pulse wave velocity (PWV), crest time (CT), stiffness index (SI), and reflection index (RI) were recorded. Two indices including normalized crest time (NCT) and crest time ratio (CTR) were also analysed and compared with the known parameters.
  
  
  RESULTS
  Though ambiguity of dicrotic notch precluded an accurate determination of the two key conventional parameters for assessing arterial stiffness (i.e. SI and RI), NCT and CTR were unaffected because the sum of CT and T(DVP) (i.e. the duration between the systolic and diastolic peak) tended to remain constant. NCT and CTR also correlated significantly with age, systolic and diastolic blood pressure, PWV, SI and RI (all P<0.01).
  
  
  CONCLUSIONS
  NCT and CTR not only showed significant positive correlations with the conventional parameters for assessment of atherosclerosis (i.e. SI, RI, and PWV), but they also are of particular value in assessing degree of arterial stiffness in subjects with indiscernible peak of diastolic wave that precludes the use of conventional parameters in waveform contour analysis.
authors.affiliation: Department of Electrical Engineering, National Dong Hwa University, Hualien, Taiwan.
authors.forename: Hsien-Tsai
authors.initials: HT
authors.lastname: Wu
authors.forename: Cyuan-Cin
authors.initials: CC
authors.lastname: Liu
authors.forename: Po-Hsun
authors.initials: PH
authors.lastname: Lin
authors.forename: Hui-Ming
authors.initials: HM
authors.lastname: Chung
authors.forename: Ming-Chien
authors.initials: MC
authors.lastname: Liu
authors.forename: Hon-Kan
authors.initials: HK
authors.lastname: Yip
authors.forename: An-Bang
authors.initials: AB
authors.lastname: Liu
authors.forename: Cheuk-Kwan
authors.initials: CK
authors.lastname: Sun
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D050197:Atherosclerosis / Q000175:diagnosis* / Q000503:physiopathology*; D001794:Blood Pressure; D002309:Cardiology / Q000379:methods; D005260:Female; D005853:Geriatrics / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D010991:Plethysmography / Q000379:methods; D012307:Risk Factors; D014655:Vascular Resistance