Functional assessment of thoracic aortic aneurysms - the future of risk prediction?

Introduction: Treatment guidelines for the thoracic aorta concentrate on size, yet acute aortic dissection or rupture can occur when aortic size is below intervention criteria. Functional imaging and computational techniques are a means of assessing haemodynamic parameters involved in aortic pathology. Sources of data: Original articles, reviews, international guidelines. Areas of agreement: Computational fluid dynamics and 4D flow MRI allow non-invasive assessment of blood flow parameters and aortic wall biomechanics. Areas of controversy: Aortic valve morphology (particularly bicuspid aortic valve) is associated with aneurysm of the ascending aorta, although the exact mechanism of aneurysm formation is not yet established. Growing points: Haemodynamic assessment of the thoracic aorta has highlighted parameters which are linked with both clinical outcome and protein changes in the aortic wall. Wall shear stress, flow displacement and helicity are elevated in patients with bicuspid aortic valve, particularly at locations of aneurysm formation. Areas timely for developing research: With further validation, functional assessment of the aorta may help identify patients at risk of aortic complications, and introduce new haemodynamic indices into management guidelines.