Dilatation of the ascending aorta is associated with presence of aortic regurgitation in patients after repair of tetralogy of Fallot

Abstract

To evaluate the association between aortic morphology and elasticity with aortic regurgitation in surgically corrected of tetralogy of Fallot (TOF) patients. We retrospectively identified 72 consecutive patients with surgically corrected TOF and 27 healthy controls who underwent cardiac MRI evaluation. Velocity-encoded cine MRI was used to quantify degree of aortic regurgitation (AR) in TOF patients. Ascending aorta diameters were measured at standard levels on MRA images. Aortic pulse-wave velocity (PWV) was quantified with MRI. Morphological and functional MRI variables were compared between groups of TOF patients with and without clinically relevant AR and controls. The association between aortic morphology and elasticity with the presence of AR was evaluated using univariate and multivariate logistic regression. The majority of TOF patients had only trace AR. Nine TOF patients (12 %) had an AR fraction higher than 15 %. Indexed aorta diameter at the sinotubular junction (p = 0.007), at the RPA level (p = 0.006), and low left ventricular ejection fraction (LVEF) (p = 0.015) showed the strongest associations with the presence of at least mild AR, which persisted after controlling for age and gender. Increased ascending aorta dimension is associated with AR in patients after repair of TOF. LVEF was also low in the group of patients with relevant AR compared to those without, suggesting even mild to moderate AR may contribute to LV dysfunction in these patients. Enlarged ascending aorta may be an indication for precise quantification of regurgitant fraction with MRI, since symptomatic patients may need aortic valve repair when moderate regurgitation is present.

Keywords: Aortic dilatation; Aortic insufficiency; MRI; Tetralogy of Fallot.

Fig. 1

Δt measurement for pulse wave velocity calculation. The Δt was defined as the difference in arrival time of the pulse wave in the ascending aorta and descending aorta. The steepest part of the flow curve was extrapolated and the intersection of this line with the baseline flow was defined as the pulse wave arrival time. Superiorly directed flow was defined as positive flow (forward flow in the ascending aorta) and inferiorly directed flow was defined as negative flow (forward flow in the descending aorta). AsAo ascending aorta, DsAo descending aorta

Fig. 2

Direct comparison between study groups: controls (0) and patients without (1) and with (2) clinically relevant aortic regurgitation. RPA right pulmonary artery, PWV pulse wave velocity, LVEF left ventricular ejection fraction, LVESVi left ventricular end-systolic volume index, LVEDVi left ventricular end-diastolic volume index

Fig. 3

Enlarged ascending aorta in a patient with tetralogy of Fallot and aortic regurgitation. Axial steady-state free precession image at the level f the aortic valve during diastole (a) shows flow jet (arrow) consistent with aortic regurgitation. Maximum intensity projection reformation of the gadolinium-enhancement MRA in an oblique sagittal plane (b) shows dilatation of the aorta at the sinotubular junction (white arrow) and level of the right pulmonary artery (arrowhead), relatively sparing the sinus of Valsalva (black arrow)