Aortic dissection beginning in the abdomen.

Two cases of aortic dissection beginning in the abdominal aorta are presented, and the angiographic and surgical principles are discussed. Every effort must be made to identify the sites of all intimal tears at aortography and to excise or oversew these sites at surgery; otherwise, dissection may continue. If an intimal tear cannot be identified at aortography, we recommend initial conservative therapy unless the patient's clinical condition forces emergency surgery.