title: A comparison of methods for assessing total arterial compliance.
abstract: There are several methods of assessing total arterial compliance (TAC) based on the two element Windkessel model, which is a ratio of pressure and volume, but the optimal technique is unclear. In this study, three methods of estimating TAC were compared to determine which was the most robust in a large group of patients with and without cardiovascular risk. In all, 320 patients (170 men; age 55+/-10) were studied; TAC was determined by the pulse-pressure method (PPM), the area method (AM) and the stroke volume/pulse-pressure method (SVPP). We obtained arterial waveforms using radial applanation tonometry, dimensions using two-dimensional echocardiography and flow data by Doppler. Clinical data, risk factors, echo parameters and TAC by all three methods were then compared. TAC (ml mm Hg(-1)) by the PPM was 1.24+/-0.51, by the AM 1.84+/-0.90 and by the SVPP 1.96+/-0.76 (P<0.0001 between groups). Correlation was good between all methods: PPM/AM r=0.83, PPM/SVPP r=0.94 and AM/SVPP r=0.80 (all P<0.0001). Subgroup analysis showed significant differences between patients with and those without cardiovascular risk for all three methods; TAC-AM and TAC-SVPP values were similar and significantly higher than TAC-PPM. The only significant relationships observed with TAC and echo parameters were in left ventricular (LV) septal thickness (R(2)=0.07; P<0.0001) and LV mass (R(2)=0.04; P=0.004). Normal and abnormal values of TAC vary according to method, which should be expressed. Each of the techniques shows good correlation with each other, however, values for TAC-PPM are significantly lower. TAC-PPM and TAC-SVPP are comparable in determining differences between groups with and without cardiovascular risk.
authors.affiliation: University of Queensland School of Medicine, Brisbane, Queensland,Australia. b.haluska@uq.edu.au
authors.forename: B A
authors.initials: BA
authors.lastname: Haluska
authors.forename: L
authors.initials: L
authors.lastname: Jeffriess
authors.forename: J
authors.initials: J
authors.lastname: Brown
authors.forename: S
authors.initials: S
authors.lastname: Carlier
authors.forename: T H
authors.initials: TH
authors.lastname: Marwick
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000502:physiology; D003187:Compliance / Q000502:physiology*; D003430:Cross-Sectional Studies; D004452:Echocardiography; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000503:physiopathology*; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000503:physiopathology; D016014:Linear Models; D008297:Male; D008365:Manometry; D008875:Middle Aged; D008955:Models, Cardiovascular; D012307:Risk Factors; D013318:Stroke Volume / Q000502:physiology; D016277:Ventricular Function, Left