title: Impact of methodology and the use of allometric scaling on the echocardiographic assessment of the aortic root and arch: a study by the Research and Audit Sub-Committee of the British Society of Echocardiography.
abstract: The aim of the study is to establish the impact of 2D echocardiographic methods on absolute values for aortic root dimensions and to describe any allometric relationship to body size. We adopted a nationwide cross-sectional prospective multicentre design using images obtained from studies utilising control groups or where specific normality was being assessed. A total of 248 participants were enrolled with no history of cardiovascular disease, diabetes, hypertension or abnormal findings on echocardiography. Aortic root dimensions were measured at the annulus, the sinus of Valsalva, the sinotubular junction, the proximal ascending aorta and the aortic arch using the inner edge and leading edge methods in both diastole and systole by 2D echocardiography. All dimensions were scaled allometrically to body surface area (BSA), height and pulmonary artery diameter. For all parameters with the exception of the aortic annulus, dimensions were significantly larger in systole (P<0.05). All aortic root and arch measurements were significantly larger when measured using the leading edge method compared with the inner edge method (P<0.05). Allometric scaling provided a b exponent of BSA(0.6) in order to achieve size independence. Similarly, ratio scaling to height in subjects under the age of 40 years also produced size independence. In conclusion, the largest aortic dimensions occur in systole while using the leading edge method. Reproducibility of measurement, however, is better when assessing aortic dimensions in diastole. There is an allometric relationship to BSA and, therefore, allometric scaling in the order of BSA(0.6) provides a size-independent index that is not influenced by the age or gender.
authors.affiliation: Research Institute for Sports and Exercise Sciences, Liverpool John Moores University , Liverpool, L3 9UT , UK.
authors.forename: David
authors.initials: D
authors.lastname: Oxborough
authors.affiliation: Department of Cardiology, Southend University Hospital NHS Trust , Westcliffe on Sea , UK.
authors.forename: Saqib
authors.initials: S
authors.lastname: Ghani
authors.affiliation: Cardiology Department, Colchester Hospital NHS Trust , Colchester , UK.
authors.forename: Allan
authors.initials: A
authors.lastname: Harkness
authors.affiliation: Cardiology Department, East Sussex Healthcare NHS Trust , Eastbourne , UK.
authors.forename: Guy
authors.initials: G
authors.lastname: Lloyd
authors.affiliation: Department of Cardiology, Queen Elizabeth Hospital , Birmingham , UK.
authors.forename: William
authors.initials: W
authors.lastname: Moody
authors.affiliation: Cardiology Department, West Suffolk Hospital NHS Trust , Bury St Edmonds , UK.
authors.forename: Liam
authors.initials: L
authors.lastname: Ring
authors.affiliation: Cardiac Ultrasound, Leeds Teaching Hospitals NHS Trust , Leeds , UK.
authors.forename: Julie
authors.initials: J
authors.lastname: Sandoval
authors.affiliation: National Heart and Lung Institute, Imperial College , London , UK.
authors.forename: Roxy
authors.initials: R
authors.lastname: Senior
authors.affiliation: Department of Cardiovascular Sciences, St Georges University of London , London , UK.
authors.forename: Nabeel
authors.initials: N
authors.lastname: Sheikh
authors.affiliation: Cardiology Department, University Hospital South Manchester , Manchester , UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Stout
authors.affiliation: Research Institute for Sports and Exercise Sciences, Liverpool John Moores University , Liverpool, L3 9UT , UK.
authors.forename: Victor
authors.initials: V
authors.lastname: Utomi
authors.affiliation: Department of Cardiology, Royal United Hospital , Bath , UK.
authors.forename: James
authors.initials: J
authors.lastname: Willis
authors.affiliation: Cardiology Department, Morriston Hospital , Swansea , UK.
authors.forename: Abbas
authors.initials: A
authors.lastname: Zaidi
authors.affiliation: Department of Cardiology, Queen Elizabeth Hospital , Birmingham , UK.
authors.forename: Richard
authors.initials: R
authors.lastname: Steeds
keywords: 2D echocardiography; allometric scaling; aortic root