AORTIC COMPLIANCE MEASURED BY NONINVASIVE DOPPLER ULTRASOUND - APPLICATION OF A PERSONAL-COMPUTER BASED MKII SYSTEM AND ITS REPEATABILITY

A non-invasive pulse-wave-velocity Doppler ultrasound technique for th e assessment of aortic compliance is described. A computational aprroa ch for correcting for the effect of non-chronic changes in blood press ure is considered and applied to compliance mearurements performed on an age-select cohort of 70 normotensive, normal healthy volunteers. In order to permit the wider availability of the pulse-wave-velocity Dop pler ultrasound technique, the authors have developed a Mk II system b ased on a standard 80486/33 MHz IBM compatible WINDOWS based personal computer; real-time spectral analysis being achieved using a relativel y inexpensive but fast analogue to digital signal processing card. An overview of the new apparatus is provided and verification work to com pare the repeatability of the Mk I and Mk II systems is described. Med ical disorders such as atherosclerosis, diabetes mellitus, familial hy percholesterolaemia, growth hormone deficiency, and Ehlers-Danlos and Marfans syndromes have all been shown to affect arterial wall complian ce. We suggest that the in vivo clinical measurement of blood pressure corrected aortic distensibility using the Mk II system may be a usefu l, reproducible, non-invasive tool for assessing such patients' suscep tibility to atheromatous arterial disease as well as for monitoring th eir response to therapeutic interventions. Measurements in the aorta m ay be especially pertinent since the natural history of fatty streaks there tends to parallel that in the coronary vasculature thereby Poten tially affording a convenient surrogate estimate of coronary heart dis ease.