Background and aim of the study: By increasing the longitudinal stress in the ascending aorta, downward movement of the aortic root might promote the proximal transverse tears seen in aortic dissections. The study aim was to evaluate the influence of five common cardiac conditions on the magnitude of aortic root displacement in cardiac patients.
Methods: Aortic root contrast injections were analyzed in 90 patients (mean age 68 years) to measure downward motion of the root perpendicular to the plane of the sinotubular junction (STJ).
Results: Displacement of the aortic root ranged from 0 to 14 mm (mean 4.8 mm). Patients with aortic insufficiency (AI) showed increased aortic root movement (7.3 versus 4.3 mm, p = 0.003), whereas those with left ventricular hypokinesis (3.7 versus 5.5 mm, p = 0.014) or with myocardial hypertrophy (3.8

versus 5.1 mm, p = 0.073) exhibited reduced downward movement. These variables were independent, and correlated with the magnitude of aortic root motion. A stress analysis of the aortic root, arch and branches of the arch determined that the longitudinal stress approximately 2 cm above the STJ, in the outer curve of the aorta, was increased by 32% in patients with AI compared to patients without AI.
Conclusion: Patients with cardiac conditions associated with increased aortic root motion such as AI may be at greater risk of aortic dissection because of increased longitudinal stress in the ascending aorta. Therefore, AI should be used as an indicator and aortic root displacement monitored to prevent the risk of aortic dissection.

The Journal of Heart Valve Disease 2005;14:610-615