title: Pressure half-time in aortic regurgitation: evaluation with Doppler in a cardiovascular hydromechanical simulator and in a computer model.
abstract: Doppler echocardiographic determination of pressure half-time has been proposed as a method of assessing the severity of aortic regurgitation. To evaluate this method, we assessed the relation between pressure half-time and simulated aortic regurgitant flow under various conditions in two models of the cardiovascular system. In a hydromechanical model we assessed the influence of total peripheral resistance and arterial compliance on the pressure half-time as measured by continuous wave Doppler echocardiography. In a computer model that used the half-time of the pressure gradient between the aorta and the left ventricle as an expression of pressure half-time, we assessed the influence of total peripheral resistance and arterial compliance and also the influence of left ventricular compliance on pressure half-time. In both models, although we found an inverse relation between regurgitant orifice area and pressure half-time, changing total peripheral resistance and arterial compliance (but not left ventricular compliance) within the physiologic range significantly altered the pressure half-times. We concluded that the influence of total peripheral resistance and arterial compliance limits the usefulness of Doppler echocardiographic determination of pressure half-time as a method of assessing the severity of aortic regurgitation.
authors.affiliation: Department of Biomedical Engineering, University of Trondheim, Norway.
authors.forename: S A
authors.initials: SA
authors.lastname: Slørdahl
authors.forename: H
authors.initials: H
authors.lastname: Piene
authors.forename: T
authors.initials: T
authors.lastname: Skjaerpe
mesh_terms: D001011:Aorta / Q000503:physiopathology; D001022:Aortic Valve Insufficiency / Q000503:physiopathology*; D001794:Blood Pressure; D002302:Cardiac Output; D003198:Computer Simulation; D015150:Echocardiography, Doppler; D006801:Humans; D008961:Models, Structural; D014655:Vascular Resistance