Abstract 10199: Increased Aortic Wall Shear Stress in Marfan Patients Long-Term After Proximal Grafting Assessed by 4D Flow Cardiac Magnetic Resonance

Abstract

Introduction: For Marfan syndrome patients (MFS) with thoracic aortic aneurysms (TAA), prosthetic graft surgery provides lifesaving benefits, but adverse event risk persists in the native aorta for which mechanism is unclear. Sustained impact of proximal grafts on biomechanics within and distal to grafts is unknown. Methods: MFS patients with chronic (> 6 month) proximal grafts were compared to non-surgical MFS (nsMFS) and age/sex matched controls: Wall shear stress (WSS) on 4D flow cardiac MRI and size (diameter) were quantified at aortic landmarks (ascending, arch, descending, thoracoabdominal). Results: 34 subjects were studied including MFS late (7.3±6.7 years) after graft implantation (n=12). Post-surgical MFS were of similar age (p=0.93) and sex (p=0.64) to controls but older than non-surgical MFS (45±10 vs 33±11 yo, p=0.01): In the ascending aorta (grafted territory), post-surgical MFS had higher WSS (1.17±0.55 Pa) than nsMFS (0.74±0.17 Pa) and controls (0.60±0.17 Pa; p=0.002 for trend). Similarly, in the (native) descending aorta, WSS was higher in post-surgical (1.06±0.24 Pa) than nsMFS (0.97±0.11) and controls (0.83±0.16; p=0.02) ( Figure ) paralleling results in the arch (p=0.06) and a similar trend in the thoracoabdominal aorta (p=0.12). Among the overall MFS cohort (n=23), proximal graft implantation associated with increased WSS in the ascending and descending aorta (both p<0.01) in analyses controlling for age and aortic size in respective territories ( Table ). Conclusions: Prosthetic grafts yield sustained alterations in aortic biomechanics, including elevated WSS (a marker of adverse remodeling) in grafted regions and the distal native aorta.