Bacteriologic and surgical determinants of survival in patients with mycotic aneurysms

Mycotic aneurysms are a fulminant infectious process frequently resulting in rupture and death if not properly treated. A review of the University of California, Los Angeles, medical records identified 10 patients with extrathoracic, extracranial mycotic aneurysms. In addition, a search of the English literature revealed 178 patients with 243 mycotic aneurysms. These patients were reviewed to identify the aneurysm location, etiology, bacteriology, and modality of treatment in order to determine the relationship between these factors and the outcome. The femoral artery was the most common site (38%), followed by the abdominal aorta (31%). Arterial trauma was the primary etiology in 42% of mycotic aneurysms. In 25% no clear source of infection could be identified. Staphylococcus aureus was cultured from 28% of mycotic aneurysms, and Salmonella from 15%. A trend toward the involvement of more gram-negative aerobes and anaerobes is noted. Aortic aneurysms were repaired with in situ Dacron in 61% of patients with a 32% mortality rate and 16% reinfection rate. Simple ligation of femoral artery mycotic aneurysms resulted in a 34% incidence of ischemia necessitating amputation. Methods of treatment of superior mesenteric, carotid, iliac, and peripheral arteries are also analyzed. On the basis of these data, specific surgical procedures are recommended for the treatment of mycotic aneurysms.