Rotational Position of the Aortic Root is Associated with Increased Aortic Dimensions in Marfan and Loeys–Dietz Syndrome

Progressive aortic dilation is common in Marfan syndrome (MFS) and Loeys–Dietz syndrome (LDS). Risk factors for progression are poorly understood. Normal variation in the aortic root (AoR) rotational position relative to the left ventricular base may impact this risk. We aimed to assess the relationship between the rotational position of the AoR and aortic dimensions in this population. Patients with a genetic diagnosis of MFS or LDS were included. AoR and ascending aorta (AAo) dimensions were measured from the first and most recent transthoracic echocardiogram. The AoR rotational angle was measured in the parasternal short-axis plane in diastole. Linear regression was used to study the correlation between AoR rotation angle and aortic dimensions. 53 MFS and 14 LDS patients were included (age 11.5 ± 5.8 years at first TTE and 21.2 ± 7.2 years at most recent, 68% male). The mean indexed AoR and AAo values were 2.26 ± 0.58 cm/m 2 and 1.64 ± 0.35 cm/m 2 at the first TTE and 1.98 ± 0.39 cm/m 2 and 1.45 ± 0.25 cm/m 2 at the most recent TTE, respectively. The mean AoR rotational angle was 8 ± 14°. AoR rotational angle was central (− 9 to + 14°) in 42, clockwise (≥ + 15°) in 19, and counterclockwise (≤ −10°) in 6. The six outliers with counterclockwise position were excluded. There was a positive association between the AoR rotation angle and most recent TTE indexed AoR ( r 2 = 0.08, p = 0.02) and AAo sizes ( r 2 = 0.08, p = 0.02). There was no association between AoR rotational angle and rate of change in indexed AoR size ( p = 0.8). There was a positive association between AoR rotation angle and rate of change in indexed AAo size ( r 2 = 0.10, p = 0.01). There is an association between clockwise rotational position of the AoR and increased AoR and AAo dimensions in children and young adults with MFS and LDS patients. The rotational position of the AoR may guide follow-up in these patient populations. However, this potential risk factor for dilation warrants further investigation.