Aortic Vorticity, Helicity, and Aortopathy in Adult Patients with Tetralogy of Fallot: Pilot Study Using Four-Dimensional Flow Magnetic Resonance Images.

Abstract

To employ quantitative analysis in the vorticity and helicity of the aortic root and the ascending aorta (AAo) in adults with tetralogy of Fallot (TOF), and to evaluate aortopathy and the relevant factors. Prospectively, 51 consecutive adults with TOF underwent 4 dimensional flow magnetic resonance imaging study for the assessment of vorticity and helicity of the aortic root and AAo, wall shear stress (WSS), viscous energy loss (EL), and the left ventricular outflow tract - aortic root (LVOT-Ao) angle. Patients were divided into the two groups: dilated aortic root and/or AAo (indexed diameter > 25mm/cm2), Group A (15 patients); non-dilated aortic patients, Group B (36 patients). Ten age-matched controls were also enrolled. Group A showed more acute LVOT-Ao angle, higher incidence of aortic regurgitation, and initial anatomy of pulmonary atresia, compared to Group B (P < 0.0001, 0.02, 0.043). Group A showed greater clockwise vorticity at the level of Valsalva, AAo, and proximal arch, sagittal vorticity, AAo helicity, WSS, and EL than in Group B (P < 0.001, < 0.001, < 0.001, 0.045, 0.049, 0.02, 0.026). More acute LVOT-Ao angle correlated with the diameter of the aortic root and AAo, AAo vorticity, helicity, WSS, and EL (P = 0.004, 0.023, 0.045, 0.004, 0.0004, 0.017). On a univariate logistic analysis, more acute LVOT-Ao angle, AAo vorticity, AAo helicity, and maximum WSS were relevant factors of AAo dilatation (P = 0.02, 0.02, 0.045, 0.03, 0.046). On a multivariate logistic analysis, more acute LVOT-Ao angle was the most important factor of AAo dilatation (odds ratio 0.66, 95% CI 0.46-0.95, P < 0.024). TOF adults presenting dilated AAo have greater vorticity, helicity, and acute LVOT-Ao angle. Flow eccentricity and these flow hemodynamic parameters may be adjunctive predictions of aortopathy in this population.