Early and late outcome of surgical repair for small abdominal aortic aneurysms: A population-based analysis

Purpose: Whether small abdominal aortic aneurysms (AAAs) (≤ 5 cm in diameter) should be repaired early to enhance late survival remains controversial. Long-term population-based data on the surgical outcome for small AAAs may help to establish practice guidelines until randomized clinical trials are completed. Methods: To examine an entire community experience with small AAAs, we conducted a population-based analysis of the recognition, reasons for operation, perioperative mortality rates, and late survival in Olmsted County, Minnesota. Results: The incidence of recognized small AAAs increased thirtyfold during a 30-year period. The propensity to repair small AAAs also increased during the same period. Eventually one third of small AAAs were repaired. The primary reasons for surgical consultation and operation were presence of the aneurysm (49%), expansion on serial examination (28%), nonspecific abdominal or back symptoms (18%), and excessive patient anxiety about the aneurysm (5%). Community operative mortality rates for small AAAs were low (2.6%) compared with those for large aneurysms (5.5%) (p = 0.65). However, the observed 5-year survival rate for the group undergoing repair of small aneurysms was 62%, which was significantly less than the 83% expected survival for the general population (p < 0.05). Relative survival for the operated small and large aneurysms was similar. The primary cause of death for both groups was myocardial infarction. Conclusions: The results of our population-based analysis indicate that early operative results for elective repair of small AAAs are excellent, but late survival remains significantly impaired by coronary heart disease. Consequently, our data question whether early repair of small AAAs will enhance late survival. Until randomized clinical trials on management of small AAAs are completed, most small AAAs should be monitored for expansion and operated on electively when they approach or enter the range of 5 to 6 cm in good-risk patients.