Clinical, microbiologic, and outcome analysis of mycotic aortic aneurysm: the role of endovascular repair

Abstract

Background: Mycotic aortic aneurysm (MAA) is an infrequent but devastating form of vascular disease.

Methods: We conducted a retrospective cohort study at a major medical center to identify independent risk factors for MAA and to provide opinions about treating it. The study population consisted of 43 patients who had had 44 MAAs over a period of 15 y.

Results: All of the patients had positive blood cultures, radiologic findings typical of MAA, and clinical signs of infection (leukocytosis, fever, and elevated C-reactive protein). The mean age of the patients was 63.8±10.6 y and the mean period of their follow up was 35.7±39.3 mo. Twenty-nine patients with MAAs underwent traditional open surgery, 11 others received endovascular stent grafts, and four MAAs were managed conservatively. The most frequent causative pathogens were Salmonella (36/44 patients [81.8%]), in whom organisms of Salmonella serogroup C (consisting mainly of S. choleraesuis) were identified in 14 patients, organisms of Salmonella serogroup D were identified in 13 patients, and species without serogroup information were identified in nine patients. The overall mortality in the study population was 43.2% (with an aneurysm-related mortality of 18.2%, surgically related mortality of 13.6%, and in-hospital mortality of 22.7%).

Conclusions: Shock is a risk factor for operative mortality. Misdiagnosis and treatment of MAA as low back pain, co-existing connective-tissue disease such as systemic lupus erythematosus and rheumatoid arthritis, and Salmonella serogroup C-associated bacteremia are risk factors for aneurysm-related death. Endovascular repair should be considered as an alternative option to the open repair of MAA.

FIG. 1.

A mycotic aortic aneurysm (MAA) presenting as hydronephrosis with urosepsis. (A) Pre-operative image of MAA. Black arrow indicates hydronephrosis with double J tube in the ureter. Black asterisk indicates MAA with content rupture and retroperitoneal hematoma. (B) Endovascular repair of MAA. White arrow indicates stent-graft in aorta. White asterisk indicates successful exclusion of the MAA.

FIG. 2.

Kaplan–Meier curves of actuarial overall survival of study patients. The open boxes represent patients undergoing endovascular repair and the black triangles represent patients undergoing open surgical repair. The probability of survival is plotted on the vertical axis and the survival period in days is plotted on the horizontal axis.