Mediastinal false aneurysm after thoracic aortic surgery

Background. Postoperative mediastinal false aneurysm is associated with a s ubstantial morbidity and mortality. Surgical treatment is mandatory, althou gh the individual approach varies according to the type of pathologic proce ss, infection status, and site of origin of the aneurysm. Methods. Between April 1993 and February 1999, we treated 10 patients, aged 25 to 73 years, with anastomotic mediastinal false aneurysm originating fr om the proximal thoracic aorta. Nine had undergone prior operations on the ascending aorta (7, type A dissection repair; 1, aortitis; 1, root abscess) with a Dacron conduit (n = 5) or valved conduit (n = 4). The last patient had undergone valve replacement for excavating aortic root sepsis. False an eurysms were detected from 2 to 70 months after the most recent operation. Three patients had positive tissue cultures. The surgical procedure was dir ect suture repair of the disrupted anastomosis in 5, root or ascending aort ic replacement with an aortic homograft in 4, and Dacron graft interpositio n in 1. Hypothermic low-now perfusion with or without circulatory arrest wa s used in all patients. Results. There was one hospital death caused by staphylococcal mediastiniti s. A false aneurysm recurred after direct suture repair in 2 patients with underlying type A dissection or aortitis. This resulted in one late death. One patient experienced a neurologic event during removal of an infected va scular graft. All 8 surviving patients are alive and well after a mean foll ow-up of 2 years. Three patients with mycotic false aneurysms remain free f rom infection after aortic homograft replacement. Conclusions. Mediastinal false aneurysms are surgically taxing. Low-flow hy pothermic perfusion with or without circulatory arrest allows safe reentry. Radical surgery provides a satisfactory outcome in infected patients. Loca l repair of suture dehiscence in pathologic tissues may predispose to recur rence. We suspect that excessive use of formalin in gelatin-resorcin-formol glue may predispose to tissue necrosis. (C) 2000 by The Society of Thoraci c Surgeons.