Log in to MyACC
Aortic Dilation and Stiffness of BAV vs. Marfan Syndrome and Degenerative Aortic Aneurysm
Study Questions:
Does regional thoracic aortic stiffness in patients with bicuspid aortic valve (BAV), as assessed by cardiovascular magnetic resonance (CMR), differ from that in patients with Marfan syndrome (MFS) or those with degenerative aortic aneurysm with tricuspid aortic valve (DA-TAV)? And how are aortic dilation and aortic valve morphology related to aortic stiffness in BAV patients?
Methods:
The CMR protocol included steady-state free-precession cine images, which were used to assess BAV morphology and measure aortic diameters, and four-dimensional phase-contrast CMR (4D flow CMR). Aortic distensibility (AD) was calculated from double-oblique cine imaging in the ascending and descending aorta at the pulmonary artery level. Pulse wave velocity (PWV) was calculated from 4D flow CMR data in the ascending and descending aorta.
Results:
This prospective study included 234 subjects (136 BAV, 44 MFS, 18 DA-TAV, 36 healthy controls). BAV phenotype was right-left fusion in 104 subjects and right-noncoronary fusion in 32 subjects. MFS subjects were significantly younger than those with BAV and DA-TAV (38 ± 13 years for MFS vs. 51 ± 14 years for BAV, p < 0.001; and 64 ± 9 years for DA-TAV, p = 0.014). After adjustment for age, diastolic blood pressure, and ascending aortic diameter, patients with BAV without aortic dilation did not differ significantly from controls in terms of PWV or AD. Conversely, MFS patients had significantly stiffer aortas than BAV patients, even after adjustment for these factors (mean PWV 6.81 in nondilated MFS vs. 4.35 in nondilated BAV, adjusted p = 0.035, and mean AD 2.0 in nondilated MFS vs. 1.8 in nondilated BAV, adjusted p = 0.015). BAV phenotype did not have a significant influence on aortic biomechanics (mean AD 1.7 in both groups, p = 0.558, and mean PWV 3.2 in right-left and 3.7 in right-noncoronary fusion, p = 0.244). In increasing quintiles of aortic dilation, BAV patients showed a trend toward increased AD (1.9 in first quintile vs. 1.0 in fifth quintile, p = not significant), while PWV decreased with increasing diameter (mean 3.4 in third quintile vs. 2.6 in fourth, p = 0.017), then increased in the fifth quintile (mean 2.9, p = 0.042). In a multivariable model including age, blood pressure, body surface area, gender, AD, and PWV, only ascending aortic PWV was significantly correlated with ascending aortic dilation in BAV patients (p < 0.001).
Conclusions:
Aortic stiffness in BAV patients is comparable to that in TAV patients and is related to degree of aortic dilation. MFS patients have stiffer aortas, even in the absence of aortic dilation.
Perspective:
This work adds to the growing body of literature considering the aneurysmal aorta as a dynamic structure. This research group recently published a study demonstrating a correlation between reduction in longitudinal aortic strain and progressive aortic dilation in MFS (see Journal Scan on Guala A, et al., Eur Heart J 2019;Apr 24:[Epub ahead of print]). One notable limitation of this study is that only Caucasian patients were included. Because the group of BAV patients with right-noncoronary fusion was small, differences between morphology groups may have been undetectable. No patient outcomes were reported, so it is unclear how measures of aortic stiffness might influence risk prediction and clinical decision making. See associated editorial for further comments (Bhave NM, Eagle KA. JACC Cardiovasc Imaging 2019;12:1030-1).
Clinical Topics: Cardiac Surgery, Congenital Heart Disease and Pediatric Cardiology, Noninvasive Imaging, Valvular Heart Disease, Vascular Medicine, Aortic Surgery, Cardiac Surgery and CHD and Pediatrics, Cardiac Surgery and VHD, Congenital Heart Disease, CHD and Pediatrics and Imaging, CHD and Pediatrics and Prevention
Keywords: Aorta, Thoracic, Aortic Aneurysm, Aortic Diseases, Blood Pressure, Body Surface Area, Diagnostic Imaging, Dilatation, Heart Valve Diseases, Magnetic Resonance Spectroscopy, Marfan Syndrome, Phenotype, Pulse Wave Analysis, Vascular Stiffness
< Back to Listings
