Dissecting aneurysm of the descending aorta. Improved surgical results in 91 patients.

Dissecting aneurysm of the descending thoraic aorta (type iii) is a specific disease process whose pathogenesis, pathologic description, surgical treatment, and prognosis is different from dissections of the ascending arota (types l and ll). From 1964 through 1974, 91 patients underwent surgical correction of type iii dissection. The operative mortality was 21% and late mortality, up to ten years follow-up, was 13%. During the past four years, operative mortality has dropped to 6.5%. Mortality was determined by extent of the aneurysm and underlying cardiac disease. Antihypertensive and negative ionotropic drugs have not been used as definitive treatment but as adjuncts in perioperative support. Based on our present mortality of 6.5%, with no late mortality, we urge early surgical treatment of acute and chronic dissecting aneurysms of the descending thoracic aorta before extension, rupture, or massive enlargement of the aneurysm occurs.