Abstract 13035: Aorta Measurements Are Genetically Determined and Influenced by Bicuspid Aortic Valve
Introduction: Bicuspid aortic valve (BAV) is the most common congenital cardiovascular malformation (CVM), with an estimated incidence of ∼ 1 to 2% in the general population. BAV patients and their relatives are at increased risk of aortic (Ao) root dilation. However, there has been little characterization of how BAV may be related to Ao diameter beyond the root.
Hypothesis: Given the increased familial incidence, we hypothesize that Ao dimensions are influenced by both underlying genetic effects as well as the presence of BAV.
Methods: We identified families enriched for BAV. All participants underwent standardized 2-dimensional and Doppler transthoracic echocardiograms using available systems (Hewlett-Packard Sonos 5500, GE Vivid 7 or a GE Vivid 5). A single experienced echocardiographer interpreted all studies and identified clinically significant findings including BAV and Ao dilation. Measures of Ao diameter (6 sites: annulus to descending Ao), mitral valve (MV) annulus, and pulmonary artery (PA) diameter were taken. Using variance components analysis, we estimated the heritability of the measures and determined the effect of BAV after accounting for age, sex and body surface area effects.
Results: We used a cohort of 162 families (n = 1090 participants). Individuals with a history of cardiac surgery were excluded. All Ao, PA and MV measures exhibited moderate to strong heritability (h2 range 0.25 ± 0.07 to 0.53 ± 0.07). Overt Ao dilation (z-score>2) was identified in 32 (2.9%) participants; individuals with BAV were at greater odds of having Ao dilation (OR = 6.76 (95% CI = 3.29 - 13.89)). Beyond overt dilation, we found that having BAV causes a statistically significant increase in all Ao and PA measures (p value range 0.009 - 3.3 × 10-25) except the descending Ao and MV.
Discussion: Our results demonstrate the importance of both underlying genetics and the presence of BAV on Ao and PA measures suggesting these measures are quantitative traits influenced by both genes and environmental factors. Since individuals with BAV had increased measures of most Ao and PA dimensions, these data suggest that an underlying BAV increases risk of Ao dilation compared to family members without BAV and the prevalence of aortopathy in BAV patients may be underestimated.
- © 2010 by American Heart Association, Inc.