3.3 ASSESSMENT OF AORTIC MORPHOLOGY IN A BICUSPID AORTIC VALVE POPULATION

Abstract

Background: Bicuspid aortic valve (BAV) is a congenital heart disease associated with aortic wall abnormalities and co-existing with other congenital defects (e.g. aortic coarctation). This study aimed to explore aortic shape features in a BAV population, identifying sub-groups with different aortic morphologies. Methods: Single-centre retrospective study. Patients with an MRI scan and native BAV diagnosis between 2011 and 16 were studied (n = 525); those with a 3D MRI dataset were included for shape analysis (n = 108, 64% males, 38 ± 16.5 years). MRI-derived 3D aortic reconstructions were analysed using a statistical shape modelling framework [1]. A mean aortic shape (‘template’) was computed and shape deformations were correlated with demographic, volumetric and functional data. Results: Aortic coarctation (n = 71) was significantly associated with a more gothic arch (p = 0.02), more tubular ascending aorta and descending aorta dilation (p < 0.001). Also, smaller aortic size in patients with coarctation was associated with the younger age of this group (33 ± 13 vs. 47 ± 19, p < 0.001), given the overall relationship between aortic size and age (p < 0.001). Aortic stenosis (n = 30) was also associated with gothic arch (p = 0.01), and dilated ascending aorta but with no aortic root dilation (p = 0.02). On multivariate regression analysis, gothic arch was indeed associated with coarctation and stenosis, and also with non-coronary valve fusion pattern (p = 0.03). Patients with aortic regurgitation tended to have larger aortas (p = 0.005). Conclusion: The presence of aortic coarctation and stenosis may influence the amount of dilation and the overall arch architecture in BAV patients. Patients with BAV present profoundly different morphological phenotypes depending on the presence/absence of aortic coarctation (Fig. 1). Figure 1Shape features of coarctation (CoA) vs no CoA in BAY population. A) The ‘template’ (or average shape) for patients with CoA on the left, and patients without CoA on the right. B) Patients with CoA have tubular ascending aortas (left), while patients without CoA tend to have increased ascending aortic dilation (right). C) Patients with CoA have more a gothic arch (left), whereas patients without CoA have a rounder arch (right).