The incidence, natural history, and outcome of secondary intervention for persistent collateral flow in the excluded abdominal aortic aneurysm

Objective: The goal of abdominal aortic aneurysm (AAA) repair is the preven tion of rupture. Exclusion of the infrarenal AAA by means of operation or e ndovascular graft placement is an alternative therapy to achieve this goal. However, thrombosis of the excluded aneurysm sac does not always occur and further intervention may be needed. This study examines the efficacy of av ailable screening methods to detect the persistence of aneurysm sac flow an d the outcome of secondary procedures to treat this problem. Methods: During the past 14 years, 1218 patients have undergone operative r etroperitoneal exclusion of AAA, To date, 48 patients have been found to ha ve persistent flow in the excluded AAA sac with duplex scanning. Twenty-sev en patients underwent surgical intervention, and seven of these procedures were performed for rupture. Six patients have undergone treatment with inte rventional techniques (four successfully). The patients were evaluated for preoperative angiographic, anatomic, and comorbid factors that may have pre disposed them to faded exclusion. Also, perioperative morbidity and mortali ty, estimated blood loss, and survival were assessed in the patients who re quired surgical treatment Results: There were no perioperative parameters that correlated with postop erative persistent flow in the excluded AAA sac. The mean time to secondary intervention was 51 months (range, 2 to 113 months). Two patients had fals e-negative computed tomographic angiogram results, eight patients had false -negative angiogram results, and six patients had duplex scan examinations that had initially negative results that were then positive for flow in sac . Reoperation had a 7.4% mortality rate (two deaths) and a median blood los s of 2600 mt, as compared with 500 mL,for primary procedures. Conclusion: Secondary operations for patent: excluded aortic aneurysm sacs have higher mortality and intraoperative blood loss rates than do primary p rocedures for AAA repair. The localization of branch leaks with computerize d tomographic angiography, angiography, and duplex scanning were imprecise, and better methods are needed to adequately diagnose patent sacs. Expansio n of AAA. sac may be the only reliable factor.