Aortic stiffness and hemodynamics in Loeys-Dietz syndrome by 4Dflow CMR: a comparison with healthy volunteers and patients with Marfan syndrome

Abstract

Abstract Background Connective tissue disorders, such as Loeys-Dietz (LDS) and Marfan (MFS) syndromes, are rare genetic diseases associated with progressive aortic dilation. Aortic dissections have been observed at lower aortic root diameters in LDS than in MFS, and research on aortic flow dynamics and biomechanics in LDS is lacking. Purpose To evaluate rotational aortic flow and aortic stiffness in LDS compared to healthy volunteers (HV) and MFS patients, using 4Dflow CMR. Methods Twenty-one LDS and 44 MFS patients, without previous aortic dissection or surgery, and 44 HV underwent a non-contrast-enhanced 4D flow CMR. In-plane rotational flow (IRF), systolic flow reversal ratio (SFRR) and local aortic diameters were obtained at 20 equidistant planes from the ascending (AAo) to the proximal descending aorta (DAo). Aortic stiffness was quantified at the AAo and DAo using pulse wave velocity (PWV). Results LDS patients had lower IRF at the distal AAo and proximal DAo compared to HV (p=0.053 and 0.004, respectively), once adjusted for age, stroke volume and local aortic diameter; but no differences were found with respect to MFS (Figure). Although SFRR at the proximal DAo was increased in LDS patients compared to both HV (p=0.037) and MFS populations (p=0.015), once adjusted for age and aortic diameter, the difference in magnitude was small (Figure). On the other hand, AAo and DAo PWV revealed stiffer aortas in LDS patients compared to HV but no differences versus MFS patients (Table). Conclusions LDS patients showed decreased in-plane rotational flow and abnormally-high regional aortic stiffness compared to healthy controls, and similar hemodynamics and aortic stiffness with respect to MFS patients Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): Instituto de Salud Carlos III, La Maratό TV3