title: Repeatability of the measurement of aortic pulse wave velocity (aPWV) in the clinical assessment of arterial stiffness in community-dwelling older patients using the Vicorder(®) device.
abstract: BACKGROUND
  Pulse wave velocity measured using the Vicorder(®) apparatus is a non-invasive indicator of arterial stiffness. The objective of this study was to assess its repeatability in older patients when used by medical professionals with limited experience of the technique.
  
  
  METHODS
  Aortic pulse wave velocity (aPWV) was measured using the Vicorder(®) system four times using the conventional pathway and twice by adapted pathway in 25 consecutive ambulant patients (15 male) after they rested supine for 15 min. A nurse and a doctor independently and alternately measured PWV using the same equipment and were blinded to their colleague's PWV readings. 'Within' and 'between' observer differences were assessed using intra-class correlation coefficients (rI) and 95% limits of agreement (95% LoA) derived from Bland-Altman plots.
  
  
  RESULTS
  Mean age was 79.8 (mean blood pressure [BP] = 133/69, Mean heart rate [HR]: 70.9). Mean PWV was 11.73 (Standard Deviation [SD] 2.6-3.6). 'Between' and 'within' observer repeatability was high, with rIs ranging from 0.8-0.93. The repeatability index for 'between' nurse and doctor measures was slightly lower (rI = 0.88) when an adapted cuff measure was used in assessing PWV compared to conventional cuff measures (rI = 0.93). Mean PWV readings 'between' observers differed by only 0.094 (95% CI -0.24 to 1.59).
  
  
  CONCLUSIONS
  When undertaken by operators with limited previous technical experience, both 'within' and 'between' observer repeatability of PWV measurement was high. This method has the potential to be included in the clinical assessment of arterial stiffness in older ambulant patients.
authors.affiliation: a Department of Geriatric and Stroke Medicine, Royal College of Surgeons in Ireland (RCSI), Beaumont Hospital , Dublin.
authors.forename: Cora
authors.initials: C
authors.lastname: McGreevy
authors.affiliation: a Department of Geriatric and Stroke Medicine, Royal College of Surgeons in Ireland (RCSI), Beaumont Hospital , Dublin.
authors.forename: Miriam
authors.initials: M
authors.lastname: Barry
authors.affiliation: b Department of Pharmacology and Therapeutics, Trinity Centre for Health Sciences, St James's Hospital , Dublin, Ireland.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Bennett
authors.affiliation: a Department of Geriatric and Stroke Medicine, Royal College of Surgeons in Ireland (RCSI), Beaumont Hospital , Dublin.
authors.forename: David
authors.initials: D
authors.lastname: Williams
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D057187:Independent Living; D008297:Male; D015588:Observer Variation; D063177:Pulse Wave Analysis / Q000295:instrumentation / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D059289:Vascular Stiffness
keywords: Pulse wave velocity; Vicorder®; arterial stiffness; elderly; reproducibility