Acute Aortic Disease.. - Index of

Natural History of Thoracic Aortic Aneurysms 185
Arteriosclerosis
Joyce et al. (51) in 1964 studied 107 patients who had nondissecting, nonsurgically
treated TAAs. Approximately 73% were considered “arteriosclerotic” in
origin, and the incidence of syphilitic aneurysms at that time had fallen to 20%.
One of the reasons that the natural history of aortic aneurysms has been
difficult to record is the fact that arteriosclerosis is so prevalent in this population.
Joyce et al. (51) attributed the most deleterious effects on survival to the presence
of associated coronary, cerebral, or other peripheral arterial occlusive or aneurysmal
disease. In their study, approximately 50% of patients with aortic aneurysms
were not alive at five years after diagnosis. Whether arteriosclerosis is a cause
of aortic aneurysm formation, or simply a coexisting disease process, is still a
matter of debate.
EVIDENCE-BASED CLINICAL DECISION-MAKING
FOR THORACIC AORTIC ANEURYSM
TAAs are serious conditions that frequently require surgical intervention due to
the threat of dissection or rupture. The natural history of aortic aneurysm is often
related to the specific location and the primary cause of the disease. The decisionmaking
process is further complicated by the greater risks of thoracic aortic
replacement compared to abdominal aortic replacement.
In developing management protocols for appropriate patient selection for
surgery, it is essential to study risk factors that may influence the natural history
of the disease. The specific objective is to select patients for whom the operative
risks are justified.
Our team at the Yale Center for Thoracic Aortic Disease has developed and
maintained a robust clinical database to:
1. Further define the natural history of TAAs in terms of thoracic aortic
growth, incidence of complications (dissection and rupture), and
survival;
2. determine risk factors for thoracic aortic growth, dissection, and
rupture; and
3. define scientific criteria for surgical intervention based on the natural
history available from these patients.
The Yale observations confirm that TAA is, over the long term, a lethal
disease. Figure 7A illustrates that patients with TAA do, indeed, have a dramatically
poorer natural outlook than an age and sex-matched general population.
Figure 7B illustrates that patients with descending aneurysms do have a poorer
outlook than those with ascending aneurysm. Figure 7C illustrates that patients
with dissection fare more poorly than patients free of dissection. And, Figure 7D
shows that prognosis depends on size of the aortic aneurysm: patients with larger
aneurysms do more poorly. Careful scrutiny of Figure 7D reveals that that TAA is