July 15, 2013
Article Review

“Effects of Aging and Body Size on Proximal and Ascending Aorta and Aortic Arch: Inner Edge-to-Inner Edge Reference Values in a Large Adult Population by Two-Dimensional Transthoracic Echocardiography”

Aortic size varies significantly with age and body size and is a predictor of cardiovascular disease. This is why obtaining an accurate assessment of the aorta is critical in guiding clinical and therapeutic decisions. A total of 500 consecutive studies between 2007 and 2012 were retrospectively included in the study in the presence of normal echocardiographic findings according to recent guidelines. The patients were referred for echocardiographic evaluation in the presence of routine cardiac evaluation, heart murmurs, suspicion of coronary artery disease, rhythm disturbances and other causes. 70 individuals had mild systemic arterial hypertension, defined as a documented history of mild high blood pressure without any abnormality on echocardiographic examination and specifically no left ventricular hypertrophy. The study aimed to include 25 or more subjects per gender and per age decade. Exclusions of poor quality echocardiographic images, obesity, diabetes, coronary, valve, congenital diseases, renal diseases, and previous cardiac percutaneous or surgical intervention. All patients were performed echocardiographic examinations, following the protocol of our laboratory. All exams were performed by iE33 or Vivid 7 ultrasound equipment with the appropriate 2D transthoracic probe. The diameters of the proximal aorta were measured at the aortic valve annulus, as the distance between the hinge points of the right and noncoronary leaflets, the diameter at the sinuses of Valsalva, the sinotubular junction, the ascending aorta, as the maximum diameter visualized, and the aortic arch, as the diameter in correspondence of the junction of the far wall of the left subclavian artery with the aorta and the angle of insertion of the aorta on the left ventricle was considered by tracing the anterior-septal wall midaxis and evaluating the angle formed with the aortic long axis through the leaflet coaptation point. All measurements were taken at end-diastole from the parasternal long axis view, except the aortic arch diameter which was taken from the suprasternal view. All measurements were taken by a single expert cardiologist. Clinical and echocardiographic characteristics are expressed as mean SD for continuous variables and as absolute numbers or percentages for categorical variables. Aortic indices were considered as absolute measures or as indexed to body surface area according to the DuBois formula. All parameters were quantified across age decades. Values in men and women were compared using unpaired tests. The relationship between aortic measurements and subject characteristics were investigated using bivariate linear regression. Independent associations between aging and aortic measurements were studied using multivariate linear regression, applying both ratiometric and allometric methods. Ratiometric AGr model was adjusted for sex only, ratiometric AGWHr included adjustments for gender, height, weight, and allometric AGWHa model was obtained adjusting for age after log transforming each aortic parameters of interest and regressing on log-transformed age, weight, and height. The latter adjustments for height and weight avoided the assumptions made in indexing measures to certain parameters of body size, such as BSA while allowing us to account for differences in body size. Patients who documented histories of mild hypertension as previously defined were documented histories in the reference ranges but excluded from further analysis concerning the influence of age and body size on normal aortic size, to avoid any possible bias of the results. To assess reproducibility, the main investigator repeated the analysis after a period of 2 weeks. A second independent observer, blinded to