Descending threshold for ascending aortic aneurysmectomy: Is it time for a 'left-shift' in guidelines?

Current guidelines on the management of thoracic aortic disease recommend that the ascending aorta be replaced when it reaches the size of 5.5 cm. Recently emerging data suggest that this criterion may need to be shifted to the left, signifying a recommendation to operate on patients with smaller aortic sizes. The data that support the need for a leftward shift in the guidelines include (1) novel and more granular data on the natural history of ascending aortic aneurysm between 5 and 6 cm showing that 2 hinge risk points exist—one at 5.25 cm, and the other at 5.75 cm; (2) aortic diameter before the moment of aortic dissection is at least 7 mm smaller than postdissection aortic size; (3) the advent of a semiautomated centerline method of imaging assessment seems to underestimate true ascending aortic size; (4) aortic surgery in the present era is very safe and its benefits outweigh the associated risks; (5) genetic testing via high-throughput next-generation sequencing identifies genetic defects responsible for aortic catastrophes at smaller aortic sizes; and (6) familial aortic dissection occurrence suggests that family members of an aortic dissection victim who harbor a sizable aneurysm should be operated on regardless of aortic size.