Aortic angle is associated with neo-aortic root dilatation and regurgitation following arterial switch operation.

Introduction: Neo-aortic root dilatation and regurgitation are common progressive long-term complications of the arterial switch operation (ASO) for transposition of the great arteries (TGA) with increasing clinical burden. While several risk factors have been identified, most are constitutional. The acute aortic angle commonly seen after ASO might alter aortic dynamics and facilitate progression of the neo-aortic root dilatation and aortic regurgitation, but insufficient data is available. We intend to assess the effect of the aortic angle in the extent of neo-aortic root dilatation and presence of regurgitation.

Methods: Retrospective analysis of TGA patients undergoing CMR after ASO at a single tertiary centre from November 2010 to July 2017.

Results: 180 patients were analysed, 157 of which having adequate imaging of the aortic arch and root. Neo-aortic root Z score was normally distributed with 73% of patients having a Z score > 2. The aortic angle had a significant (p < 0,001) inverse relationship with the neo-aortic root Z score both in univariate and multivariate linear regression. Other significant associations were male gender and the concomitant presence of a VSD or a dysplastic neo-aortic valve. The presence of neo-aortic regurgitation was also inversely correlated with the aortic angle. The presence of a bicuspid neo-aortic valve was another significant association, further correlating with the more severe forms.

Conclusions: Acute aortic angles associate more extensive neo-aortic root dilatation and higher incidence of regurgitation. We believe a surgical technique promoting less acute aortic angles has potential for ameliorating the long-term outcomes of TGA.