Abstract 14415: Aortic Strain and Stiffness in Patients with Turner and Marfan Syndrome: Non-Invasive Phenotyping of Aortic Biomechanical Properties

Introduction: Turner and Marfan Syndromes (TS and MFS) are hereditary connective tissue disorders with increased risk of aortic aneurysm and rates of dissection. Prior studies suggest that TS and MFS have increased aortic stiffness when compared to healthy controls but comparative phenotyping of central aortic stiffness between the two syndromes has not yet been performed. Hypothesis: Non-invasively derived aortic biomechanical properties will differ between MFS and TS patients. Methods: Patients underwent cardiac MRI to evaluate central aortic strain and stiffness. Circumferential strain was evaluated using relative area change (RAC) for both the ascending and descending aorta and longitudinal aortic strain (LAS) was measured in the ascending aorta. Stiffness was evaluated using pulse wave velocity (PWV) and by wave-intensity analysis derived backward compression wave (BCW) ratio measuring stiffness of arch and abdominal vessels. Results: Patients with TS (N=53, mean age: 17.2±5.4) and MFS (N = 22, mean age: 17.8±6.2) had similar ascending aortic size and z-score. When compared to TS, MFS patients had reduced RAC in both ascending (33 vs 16%, P < 0.05) and descending aorta (24 vs 14%, P < 0.01) (Figure). PWV was increased in MFS in both ascending (4.0 vs 3.0 m/s, P < 0.01) and descending aorta (3.8 vs 4.7 m/s, P < 0.01). LAC was reduced in MFS patients as well (14 vs 8%, P < 0.01). Lastly, MFS had increased BCW ratio for arch vessel stiffness (0.11 vs 0.26, P < 0.01) with no difference in abdominal vessels (0.35 vs 0.36, P = NS). Conclusion: In contrast to TS, MFS patients have comparably increased stiffness and reduced compliance throughout the central aorta including aortic arch vessels. These differences are in parallel with clinical observations describing higher rate of aortic events throughout the entire aorta in patients with MFS. Our results might also be critical given the increasingly dominant role of biomechanical indices in the risk assessment for aortic events.