Extended Arch Procedures for Acute Type A Aortic Dissection: A Downstream Problem?

Current discussion regarding the management of acute type A aortic dissection is focused on whether to perform a standard hemiarch resection or perform an extended repair, in hopes of improving long-term outcomes by avoiding late, distal aortic sequelae. Critical to this discussion is an estimation of the short-term risks of an extended procedure and the magnitude of the late "downstream problem." Extension of the hemiarch to a total arch plus frozen elephant trunk does not improve survival; carries some increased perioperative risk, not the least of which is paraplegia; but decreases late aortic events, the most common of which is reoperation on the distal aorta. However, these reoperations are low frequency, primarily elective, low-risk events and it should be noted that extended index repairs do not eliminate or necessarily decrease the incidence of late reoperations. Routine extension of the index procedure puts 100% of patients at risk in order to protect a minority that may benefit. Therefore, it is important to select patients at high risk for reoperation if an extended repair is to be performed. Predictors that may identify this high-risk group include the size and location of the entry tear, aortic and luminal dimensions, degree of luminal flow and thrombosis, and the presence of a connective tissue disorder. Timing may also be important and, in patients at high risk for late events, early complications may be minimized by strategies that delay an extension of the proximal repair until the subacute period.