Abstract 14443: Aortic Root Rotational Position Associates With Aortic Valve Incompetence and Aortic Dilation After Arterial Switch Operation for Transposition of the Great Arteries

Abstract

Introduction: Variation in aortic root (AoR) rotational position affects flow dynamics in normal patients. Complications of arterial switch operation (ASO) for transposition of the great arteries (TGA) include aortic dilation and neo-aortic regurgitation (AR). We sought to assess the association of neo-AoR rotational position with neo-AoR and ascending aorta (AA) dilation and neo-AR in TGA after ASO. Methods: Patients after ASO for TGA who underwent cardiac magnetic resonance (CMR) from 2005-2020 were retrospectively reviewed. Neo-AoR rotational angle, indexed (to height) neo-AoR and AA dimensions, indexed left ventricular end diastolic volume (LVEDVi), and neo-aortic regurgitant fraction (RF) were obtained from CMR. Multivariable regression analysis for neo-AoR and AA dilation, RF, and LVEDVi were performed. Results: A total of 36 patients (78% male) were included. Median age at ASO was 5 days (3, 7) and at CMR was 17.1 years (12.3, 21.9). Rotational angle was 25% counterclockwise (<-9°), 25% central (-9 to +14°), and 50% clockwise (>+15°). There was no material association of neo-AoR and AA size with sex, age, and coronary artery anatomy. A quadratic term for neo-AoR rotational angle - increasing extremes of counterclockwise and clockwise angles - was significantly associated with neo-AoR dilation (p=0.03), AA dilation (p<0.02), and LVEDVi (p<0.01) (Figure 1) and remained significant in multivariable model of neo-AoR dilation (p<0.02), AA dilation (p<0.01), and LVEDVi (p<0.02). Rotational angle was negatively associated with neo-aortic RF (p<0.05) and remained significant in multivariable model (p<0.02). Conclusions: In conclusion, both clockwise and counterclockwise neo-AoR rotational position in TGA after ASO are associated with neo-AoR and AA dilation and LVEDVi. Counterclockwise rotational angle was associated with RF. Neo-AoR rotational position likely affects valve function and hemodynamics, leading to risk of neo-AR and aortic dilation.