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

https://doi.org/10.1016/j.echo.2021.09.011Get rights and content

Highlights

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    Normal values of aortic root dimensions were obtained from 1,585 healthy adults.

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    Normal limits were established for aortic annulus, SoV, and STJ.

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    Normal values differ by age, sex, and race.

Background

Accurate 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 study, the authors sought to establish normal ranges of aortic dimensions across sexes, races, and a wide range of ages.

Methods

Adult individuals free of heart, lung, and kidney disease were prospectively enrolled from 15 countries, with even distributions among sexes and age groups: young (18–40 years), middle aged (41–65 years) and old (>65 years). Transthoracic two-dimensional echocardiograms of 1,585 subjects (mean age, 47 ± 17 years; 50.4% men; mean body surface area [BSA], 1.77 ± 0.22 m2) were analyzed in a core laboratory following American Society of Echocardiography guidelines. Measurements, indexed separately by BSA and by height, included the aortic annulus, sinuses of Valsalva, and sinotubular junction. Differences among age, sex, and racial groups were evaluated using unpaired two-tailed Student's t tests.

Results

All aortic root dimensions were larger in men compared with women. After indexing to BSA, all measured dimensions were significantly larger in women, whereas men 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 with the guidelines. Aortic dimensions were larger in older age groups in both sexes, a trend that persisted regardless of BSA or height adjustment. Last, differences in aortic dimensions were also observed according to race: Asians had the smallest nonindexed aortic dimensions at all levels.

Conclusions

There 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.

Section snippets

Study Design and Population

The rationale and design of the WASE study has been described in detail elsewhere.3 Briefly, this is a multicenter, international, observational, prospective, cross-sectional study of healthy adult individuals. The ASE invited representatives of all member societies of the ASE International Alliance Partners to participate in this study. Each participant center was tasked with enrolling 100 local healthy adult volunteers without histories or clinical evidence of heart, lung, or kidney disease.

Results

A total of 1,585 subjects (50% men; mean age, 47 ± 17 years) formed the final population of the 2D analysis of the periannular aortic dimensions after the exclusion of subjects who did not have complete data sets suitable for analysis. Basic demographic characteristics of the study population, including race and ethnicity, are listed in Table 1. Most individuals were white (n = 540 [34.1%]) or of Asian race (n = 687 [43.3%]), with a minority being black (n = 182 [11.5%]) or mixed race (n = 176

Discussion

This WASE study of aortic dimensions provides normal values by transthoracic echocardiography from a large cohort of healthy subjects across the spectrum of sex, age, and race. The main findings are summarized as follows: (1) aortic dimensions were larger in men compared with women and remained so when adjusted for height but not when adjusted for BSA, (2) aortic dimensions generally are larger in older age, and (3) aortic dimensions vary according to ethnicity.

Echocardiography is a widely

Conclusion

Our results from the WASE Normal Values Study provide normal reference ranges for aortic dimensions, which differ according to sex, age, and race. Current guideline-recommended normal ranges may need to be adjusted to account for these differences.

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Linda D. Gillam, MD, MPH, FASE, served as guest editor for this report.

Mr. Schreckenberg, Mr. Blankenhagen, Mr. Degel, and Mr. Hitschrich are employees of TomTec Imaging Systems.

The WASE Study was supported by the American Society of Echocardiography.

†

A list of additional WASE investigators is provided in the Appendix.

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2021 by the American Society of Echocardiography.