ABSTRACT
Thoracic aortic aneurysms (TAAs) (Fig. 1) have an annual incidence in populationbased studies of as high as 10.4 per 100,000 persons (1). The population based annual rate of thoracic aneurysmal rupture or dissection was 7.0 per 100,000 (2) in one study, and the rate of rupture was 5.0 per 100,000 in another (3). The gravity of these occurrences is illustrated by the median survival of three days after aneurysmal dissection in the former study (2), and the 97% to 100% mortality after rupture in the latter (3). The public health impact of this disease can be brought into focus by comparing these rates to the 5.0 per hundred thousand mortality rate from Human Immunodeficiency Virus infection in the United States (4). Operative repair of TAAs is effective in improving survival (5). However, elective surgical repair for asymptomatic aneurysms remains a clinical decision, which must be based on the patient’s operative risk, and the risk that a given TAA will progress, dissect, or rupture. In order to consider the risks of these complications, a thorough understanding of both the natural history and the pathophysiology of TAAs are required.
