Original article: cardiovascular
Yearly rupture or dissection rates for thoracic aortic aneurysms: simple prediction based on size

Presented at the Thirty-seventh Annual Meeting of The Society of Thoracic Surgeons, New Orleans, LA, Jan 29–31, 2001.
https://doi.org/10.1016/S0003-4975(01)03236-2Get rights and content

Abstract

Background. Prior work has clarified the cumulative, lifetime risk of rupture or dissection based on the size of thoracic aneurysms. Ability to estimate simply the yearly rate of rupture or dissection would greatly enhance clinical decision making for specific patients. Calculation of such a rate requires robust data.

Methods. Data on 721 patients (446 male, 275 female; median age, 65.8 years; range, 8 to 95 years) with thoracic aortic disease was prospectively entered into a computerized database over 9 years. Three thousand one hundred fifteen imaging studies were available on these patients. Five hundred seventy met inclusion criteria in terms of length of follow-up and form the basis for the survival analysis. Three hundred four patients were dissection-free at presentation; their natural history was followed for rupture, dissection, and death. Patients were excluded from analysis once operation occurred.

Results. Five-year survival in patients not operated on was 54% at 5 years. Ninety-two hard end points were realized in serial follow-up, including 55 deaths, 13 ruptures, and 24 dissections. Aortic size was a very strong predictor of rupture, dissection, and mortality. For aneurysms greater than 6 cm in diameter, rupture occurred at 3.7% per year, rupture or dissection at 6.9% per year, death at 11.8%, and death, rupture, or dissection at 15.6% per year. At size greater than 6.0 cm, the odds ratio for rupture was increased 27-fold (p = 0.0023). The aorta grew at a mean of 0.10 cm per year. Elective, preemptive surgical repair restored life expectancy to normal.

Conclusions. This study indicates that (1) thoracic aneurysm is a lethal disease; (2) aneurysm size has a profound impact on rupture, dissection, and death; (3) for counseling purposes, the patient with an aneurysm exceeding 6 cm can expect a yearly rate of rupture or dissection of at least 6.9% and a death rate of 11.8%; and (4) elective surgical repair restores survival to near normal. This analysis strongly supports careful radiologic follow-up and elective, preemptive surgical intervention for the otherwise lethal condition of large thoracic aortic aneurysm.

Section snippets

Patient population

Our database now includes information on 721 patients with TAAs. There are 2,276 total patient-years of follow-up and 1,383 patient-years of follow-up preceding operation, from which natural history can be assessed. We have analyzed 3,115 radiographic studies (985 computed tomographic scans, 418 magnetic resonance imaging scans, 139 transesophageal echocardiography studies, 1,344 transthoracic echocardiography studies, and 229 angiographic studies) of patients with thoracic aortic disease.

Aneurysm characteristics

The distribution of aneurysms by initial size is shown in Table 1. Aneurysms of the ascending aorta were substantially more common than the others. The mean initial aortic size for patients with Marfan syndrome was significantly smaller than for those without (4.6 versus 5.1 cm, p = 0.0001); in addition, aneurysms of the aortic arch and thoracoabdominal aorta were significantly larger than those of the ascending aorta (5.9 and 5.7 versus 4.8 cm, p < 0.005).

Aneurysm growth rates

Aneurysm growth rates were calculated

Comment

Examining the natural history of TAAs is complicated by a number of issues specific to the disease, which make scientific assessments of risks difficult. Patients with large aneurysms or high rates of growth between imaging studies and those with significant symptoms are usually selected for surgical intervention. Those who are not selected for operation may have been excluded as surgical candidates because of significant comorbidities. Therefore, studies of risk factors for complications

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