Association between bicuspid aortic valve morphotype and regional dilatation of the aortic root and trunk

Abstract

Thoracic aortic disease, including thoracic aortic aneurysm (TAA), is frequently seen in patients with bicuspid aortic valve (BAV). We hypothesized that BAV morphotype would be associated with aortic aneurysm phenotypes but that other patient variables would significantly modify this relationship. 829 patients between 18 and 90 years with BAV and available raw imaging of the aortic valve and the ascending aorta to its mid-portion prior to aortic valve and aortic surgery were examined. The sinuses of Valsalva and proximal ascending aorta were measured from 2-dimensional co-planar echocardiographic images. We observed strong associations between patient habitus and raw and normalized dimensions of the aortic root and ascending aorta. Patients with R-L morphotype presented at an older age with larger aortic root but similar ascending aortic dimensions. After accounting for patient morphometric characteristics and severity of aortic valve disease, patients with R-L valve morphotype were marginally more likely to have an aortic root aneurysm (86% vs. 78%; P = 0.043), defined as aortic root dimension Z score ≥3. We observed only small differences in aortic dimensions between BAV morphotypes, that are eclipsed by variation in patient habitus. We interpret these findings to mean that BAV patients will not likely benefit from therapies based on aortic valve morphotype. Rather, we propose that all BAV patients should undergo longitudinal follow-up, independent of valve morphotype. Guidelines for aortic surgery based upon dimensions alone may be improved by considering patient characteristics such as age, body size and other characteristics.

Bicuspid aortic valve morphology and its impact on aortic diameters—A systematic review with meta‐analysis and meta‐regression

“…A total of 220 articles were analyzed as full texts. Of these, 23 met inclusion criteria: for analysis of SVD 4 studies with indexed, 12 with nonindexed and 4 with both aortic diameters and AAD 8 studies with indexed, 11 with nonindexed and 4 with both aortic diameters and were finally included in the meta‐analysis (Figure ). The final meta‐analysis included 1271 patients for the evaluation of indexed SVD and 3454 patients of nonindexed SVD and 2192 patients for evaluation of indexed AAD and 3104 for nonindexed AAD.…”

Pathogenic Mechanisms of Bicuspid Aortic Valve Aortopathy

“…This similarity is reinforced by the observation of decreased tissue fibrillin and increased TGF-β content in both (Nataatmadja et al, 2013 ). But surprisingly, if we expected the root aneurysm phenotype of both Marfan syndrome and BAV to mirror the distribution of CNC migration, BAV morphotype is not well-correlated with aortic aneurysm morphotype (Jackson et al, 2011 ; Habchi et al, 2017 ).…”

“…About 15% of patients with AAD have a dilated aortic root characterized by dilated sinuses and annulus, often including the sinotubular junction; these patients present at a younger age because of the severity of aortic incompetence, occurring in the absence of CAVD. This phenotype has been more frequently associated with right-left cusp fusion (Jassal et al, 2010 ; Della Corte et al, 2014a ), but not reliably so (Girdauskas et al, 2016b ; Habchi et al, 2017 ). In contrast to the accelerated CAVD seen in patients with BAV having the tubular ascending aortic phenotype, which perhaps results from abnormal aortic shear stress, this phenotype probably results from a primary structural lesion of the aortic root and annulus rather than occurring secondarily to altered aortic wall stresses, with the aortic incompetence directly resulting from the aortic annulus and root lesion.…”

“…Some patients with a seemingly normally functioning BAV exhibit early and marked tubular AAD, while conversely, many patients with long-standing BAV and CAVD do not have AAD. The association between BAV morphotype (right-left vs. right-non-coronary fusion) and aortic phenotype (root vs. tubular) is weak (Habchi et al, 2017 ), and mechanistic studies still do not explain the overall phenotypes. It is recognized that merely accounting for the severity of valve disease, the configuration of the valve, the presence or absence of a raphe, or aortic dimensions does not describe the severity of aortic wall disease, or risk of future adverse events (Fedak et al, 2016 ).…”

The aortic root does not dilate over time after replacement of the aortic valve and ascending aorta in patients with bicuspid or tricuspid aortic valves

“…Certain BAV fusion types are associated with different presentations of aortopathy. [30][31][32] However, we did not have a large enough sample size to examine aortic size progression according to BAV fusion type. Similarly, most patients in our study had a stenotic aortic valve and we were unable to identify those with a root phenotype (annuloaortic ectasia and aortic insufficiency), who would be more at risk of an aortic root aneurysm.…”