Significance of intraoperative cultures of abdominal aortic wall and thrombus

Over the past decade, several studies of bacterial cultures of aortic aneurysms have been undertaken in an effort to evaluate the contents of the aneurysm wall as potential source for prosthetic graft infection. In this prospective study, 59 patients underwent infrarenal aortic aneurysm repair and had cultures taken from the aneurysm wall and thrombus; all patients received the same antibiotic prophylaxis. Positive cultures were obtained from 27 (45.7%) of the 59 aneurysms: cultures were more frequently positive if taken from ruptured (69%) aneurysms than from elective (39%) cases. We had only 1 case of early prosthetic graft infection: this patient, operated 4 days after the beginning of symptomatology (ruptured aneurysm), presented positive culture from the aneurysm contents. During an average follow-up period of 14 months (range, 2 to 20 months), no other graft infections were documented, also in the group with positive cultures (one year after operation, 28 patients were submitted to CT-scan). This study confirms the high incidence of positive cultures from the abdominal aortic contents but fails to confirm that the presence of positive cultures may increase the risk of subsequent graft infection.