title: The noninvasive estimation of central aortic blood pressure in patients with aortic stenosis.
abstract: OBJECTIVE
  To determine the relationship between brachial blood pressure, and transfer function-estimated and invasively measured central aortic pressure in patients with at least moderate symptomatic aortic stenosis.
  
  
  METHODS
  Fourteen patients aged 54-81 years with mean (SD) effective valve area of 0.69 (0.20) cm2, undergoing coronary angiography, had simultaneous peripheral and central aortic blood pressure measurements. Brachial blood pressure was determined by an oscillometric method. Aortic pressure was measured directly using pressure transducer tipped catheters, and estimated indirectly by the application of a transfer function to a radial arterial waveform obtained by tonometry.
  
  
  RESULTS
  Measured aortic systolic pressure did not differ significantly from brachial pressure [mean difference (SD) 2 (9) mmHg, P = not significant (NS)]. Transfer function estimates of central systolic pressure obtained from the radial waveform calibrated from brachial pressure were less accurate [mean difference -8 (7) mmHg, P = 0.001]. Recalibration of the radial waveforms using the invasive mean and diastolic blood pressure improved the agreement [mean difference -2 (6) mmHg, P = NS] but did not provide a better estimate than brachial blood pressure. The accuracy of noninvasively estimated subendocardial viability ratio was substantially improved by recalibration of radial arterial waveforms using corrected ejection time.
  
  
  CONCLUSIONS
  In patients with aortic stenosis there is clinically acceptable agreement between noninvasive brachial pressure and directly measured central aortic pressure.
authors.affiliation: Department of Cardiology, St Thomas' Hospital, Lambeth Palace Road, London, UK.
authors.forename: Ronak
authors.initials: R
authors.lastname: Rajani
authors.forename: Phil
authors.initials: P
authors.lastname: Chowienczyk
authors.forename: Simon
authors.initials: S
authors.lastname: Redwood
authors.forename: Antoine
authors.initials: A
authors.lastname: Guilcher
authors.forename: John B
authors.initials: JB
authors.lastname: Chambers
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001011:Aorta / Q000503:physiopathology*; D001024:Aortic Valve Stenosis / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination / Q000379:methods; D001916:Brachial Artery / Q000502:physiology; D017023:Coronary Angiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D011673:Pulsatile Flow / Q000502:physiology; D017534:Radial Artery / Q000502:physiology; D012039:Regional Blood Flow / Q000502:physiology