You have now learned how to answer the four focused questions:
• Is a pericardial fluid collection present? • Is the left ventricle systolic function reduced? • Are signs of aortic stenosis present? • Are signs of right heart strain present? • Are signs of hypovolemia present?
Facts • The ascending aortic diameter is highly variable and increases with increasing body-surface area and age. • An ascending aortic maximum diameter >5 cm is always pathological – regardless of age and body-size. • An aortic maximum diameter <3.5 cm makes aortic dissection unlikely. • Approximate distribution of size at the time of dissection: <4 cm: 5% , 4-5 cm: 35%, >5 cm: 60%.
Tips • The ascending aorta is measured at the point of largest diameter. • Precise measurements are done perpendicular to a line through the centre of aorta during systole. • The aortic diameter is measured from the leading edge of the anterior aortic wall to leading edge of the posterior aortic wall.
Facts No ultrasonographic finding can rule out aortic dissection.
However, in combination with relevant symptoms, four findings are highly suggestive of type A aortic dissection: • the presence of a dissection membrane • loss of sino-tubular junction • largest ascending aorta diameter >5 cm • pericardial fluid collection
Two findings reduce a suspicion of type A aortic dissection: • preserved sino-tubular junction • largest ascending aortic diameter <3.5 cm