Aortic root dimensions are predominantly determined by genetic factors: a classical twin study
Previous studies using transthoracic echocardiography (TTE) observed moderate heritability of aortic root dimensions. Computed tomography angiography (CTA) might provide more accurate heritability estimates. Our primary aim was to assess the heritability of the aortic root with CTA. Our secondary aim was to derive TTE-based heritability and compare this with the CTA-based results.
In the BUDAPEST-GLOBAL study 198 twin subjects (118 monozygotic, 80 dizygotic; age 56.1 ± 9.4 years; 126 female) underwent CTA and TTE. We assessed the diameter of the left ventricular outflow tract (LVOT), annulus, sinus of Valsalva, sinotubular junction and ascending aorta. Heritability was assessed using ACDE model (A additive genetic, C common environmental, D dominant genetic, E unique environmental factors).
Based on CTA, additive genetic effects were dominant (LVOT: A = 0.67, E = 0.33; annulus: A = 0.76, E = 0.24; sinus of Valsalva: A = 0.83, E = 0.17; sinotubular junction: A = 0.82, E = 0.18; ascending aorta: A = 0.75, E = 0.25). TTE-derived measurements showed moderate to no genetic influence (LVOT: A = 0.38, E = 0.62; annulus: C = 0.47, E = 0.53; sinus of Valsalva: C = 0.63, E = 0.37; sinotubular junction: C = 0.45, E = 0.55; ascending aorta: A = 0.67, E = 0.33).
CTA-based assessment suggests that aortic root dimensions are predominantly determined by genetic factors. TTE-based measurements showed moderate to no genetic influence. The choice of measurement method has substantial impact on heritability estimates.
• Aortic root dimensions are determined by genetic and environmental effects.
• Transthoracic echocardiography (TTE) demonstrated moderate to no genetic effects on aortic root dimensions.
• Computed tomography angiography might provide more accurate heritability estimates compared to TTE.
• Three-dimensional imaging techniques are needed to reliably quantify aortic root dimensions.
KeywordsAscending aorta Multidetector computed tomography Transthoracic echocardiography Twins Genetic determinism
Abbreviations and acronyms
additive genetic, common environment, dominant genetic, unique environment
body mass index
computed tomography angiography
left ventricular outflow tract
The authors thank Levente Littvay, PhD, from the Central European University (Budapest, Hungary) for his instrumental help in the statistical analysis. The scientific guarantor of this publication is Pál Maurovich-Horvat MD, PhD, MPH. The authors of this manuscript declare relationships with the following companies: Szilard Voros, MD, is a shareholder in Global Genomics Group, LLC, and receives salary from Global Genomics Group, LLC. This study has received funding by a grant from the EFSD (European Foundation for the Study of Diabetes) New Horizons Program to György Jermendy, MD. Global Genomics Group contributed funding for CT imaging and blood-based biomarker measurements. One of the authors has significant statistical expertise. Institutional review board approval was obtained. Written informed consent was obtained from all subjects (patients) in this study. Methodology: prospective, classical twin study, performed at one institution.
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