Surgery insight: the dilated ascending aorta--indications for surgical intervention.

Awareness of the clinical significance of thoracic aortic aneurismal disease has increased in recent years. As diagnostic tools have improved our ability to identify aortic pathology, surgical outcomes have also improved, making intervention a life-saving option in the majority of cases. Here, we aim to examine the indications for surgical intervention on the dilated aorta, particularly the ascending segment. Studies of the natural history of ascending aortic aneurysms indicate that aneurysms exceeding 6 cm in maximum diameter are associated with a particularly high risk of complications. In the interest of providing some margin of safety, most surgeons would agree that intervention is indicated with an aortic diameter of 5.5 cm. Many would intervene even earlier (at 5.0 cm) for patients at low surgical risk, or for those with known connective tissue disorders such as Marfan's syndrome. In some cases, only the ascending aortic segment needs to be treated, while in others full root replacement is required. Reduction aortoplasty has been superseded largely by interposition graft replacement. The standard procedure involves replacement of the valve and root with a composite mechanical conduit or tissue root prosthesis, and results are excellent. Recently developed valve-sparing root reconstructive options, however, are promising and have encouraged an even more aggressive surgical stance.