Quick Fire Session
SCMR 22nd Annual Scientific Sessions
Ascending aorta (AAo) dilation is usually associated with the presence of bicuspid aortic valve (BAV). Despite abnormal flow patterns has been related to aortic dilation, aortic extracellular matrix dysregulation and elastic fiber degeneration in BAV patients; there is still controversy about the presence of intrinsic aortic wall alterations in this population. Nonetheless, the increase occurrence of aortic aneurysm within BAV families and the fibrillin-1 deficiency in the AAo of BAV patients have supported the existence of intrinsic degeneration of the aortic wall, similar to those reported in Marfan syndrome patients (MFS).
We aim (1) to assess the influence of AAo dilation on regional stiffness parameters in BAV patients and (2) to analyze the existence of an intrinsic alteration in regional aortic stiffness in BAV patients by comparing them with healthy volunteers, degenerative aneurysm with tricuspid aortic valve (DA-TAV) and MFS patients with and without aortic dilation.
Methods: Two hundred and thirty-four subjects (136 BAV, 44 Marfan, 18 DA-TAV and 36 healthy controls) were prospectively included. Ascending and descending aorta (DAo) pulse wave velocities (PWV) were assessed with 4D flow MRI, whereas distensibility (AD) was computed with double-oblique 2D steady-state free-precession cine CMR. Aortic dilation was defined when z-score > 2 considering AAo and root maximum diameters. A two-tailed p value < 0.05 was considered statistically significant.
Results: PWV and AD, in both AAo and DAo, were similar in dilated BAV and DA-TAV patients and between non-dilated BAV and healthy volunteers. Conversely, AAo and DAo stiffness was markedly increased in MFS patients compared to BAV patients. In BAV patients, AAo PWV presented a biphasic pattern: first decreased and then increased throughout AAo dilation, with a clear turning point at 50 mm, while distensibility did not discern mildly-dilated aorta (see figure 1).
Aortic stiffness strongly depends on dilation severity. Whereas BAV and TAV patients present a similar AAo and Dao stiffness, MFS patients have a stiffer aorta at both locations. While distensibility did not discern mildly-dilated aorta, AAo PWV resulted in a possibly clinically-useful biphasic trend with respect to aneurysm diameter.