Risk factors for descending aortic aneurysm formation in medium-term follow-up of patients with type A aortic dissection

BACKGROUND: After surgery to repair a type A aortic dissection, most late complications and mortality result from descending aorta-related problems. This study was performed to determine the risk factors leading to descending aortic aneurysm formation and late mortality in patients undergoing the type A aortic dissection operation. METHODS: The medical records of patients who survived the operation for type A aortic dissection between 1984 and 1998 were reviewed. There were 144 patients (95 men and 49 women), ranging in age from 24 to 78 years (mean age, 52 years). Most patients were acutely ill, 15 patients were in shock, and 54 patients had cardiac tamponade at the time of the surgical procedure. One hundred thirty-seven patients had ascending aortic replacement only, and of the other 6 patients 2 had hemiarch and 4 had total arch replacement using the elephant trunk technique. The aortic valve was replaced in 23 patients, resuspended in 100, and untouched in 21. Twenty-four risk factors were evaluated in statistical analyses for the prediction of descending aortic aneurysm formation and 3-year mortality. Risk factors were investigated using univariate and multiple logistic regression and survival analyses. RESULTS: The 3-year, 5-year, and 8-year cumulative survival rates were 96.2%, 89.1%, and 80.0%, respectively. The 3-year, 5-year, and 8-year cumulative survival rates, free from descending aortic aneurysm formation or descending aorta operation, were 74.7%, 58.6%, and 43.0%, respectively. Multivariate analysis confirmed that patent false lumen and initial descending aortic diameter were statistically significant risk factors for descending aortic aneurysm formation. CONCLUSIONS: The medium-term survival rate of patients who received operations for type A aortic dissection was satisfactory, despite the high incidence of descending aortic aneurysm formation. The intimal entry site over the aortic arch that was resected during the first operation could decrease the patency rate of a false lumen over the descending aorta. In the absence of a patent false lumen over the descending aorta, the chance of descending aortic aneurysm formation or operation is lessened, and the late survival rate is increased.