Normal Values of Aortic Root Size According to Age, Sex and Race: Results of the World Alliance of Societies of Echocardiography Study.

Abstract

BACKGROUND\nAccurate measurements of the aortic annulus and root are important for guiding therapeutic decisions regarding the need for aortic surgery. Current echocardiographic guidelines for identification of aortic root dilatation are limited because current normative values were derived predominantly from white individuals in narrow age ranges, and based partially on M-mode measurements. Using data from the World Alliance Societies of Echocardiography (WASE) Study, we sought to establish normal ranges of aortic dimensions across sexes, races and a wide range of ages.\n\n\nMETHODS\nAdult individuals free from heart, lung and kidney disease were prospectively enrolled from 15 countries with even distribution among sexes and age groups: young (18-40), middle (41-65) and old (>65 years). Transthoracic 2D echocardiograms of 1,585 subjects (age 47±17 years, 50.4% male, body surface area (BSA) 1.77±0.22 m2) were analyzed in a core laboratory following ASE guidelines. Measurements, indexed separately by BSA and by height, included the aortic annulus, sinuses of Valsalva (SoV), and sinotubular junction (STJ). Differences among age, sex and racial groups were evaluated using unpaired two-tailed student s t-tests.\n\n\nRESULTS\nAll aortic root dimensions were larger in males compared to females. After indexing to BSA, all measured dimensions were significantly larger in females, whereas males continued to show larger dimensions after indexing to height. Of note, the upper limits of normal for all aortic dimensions were lower across all age groups, compared to the guidelines. Aortic dimensions were larger in older age groups in both sexes, a trend that persisted regardless of BSA- or height adjustment. Lastly, differences in aortic dimensions were also observed according to race: Asians had the smallest non-indexed aortic dimensions at all levels.\n\n\nCONCLUSIONS\nThere are significant differences in aortic dimensions according to sex, age, and race. Thus, current guideline-recommended normal ranges may need to be adjusted to account for these differences.