Is there an advantage in using homografts in patients with acute infective endocarditis of the aortic valve?

BACKGROUND AND AIM OF THE STUDY: Acute infective endocarditis is a surgical challenge, particularly when paravalvular abscesses and annular destruction are present. The choice of a homograft or mechanical valve prosthesis is an important issue in these patients. The study aim was to compare the outcome with homografts and mechanical valves in patients with acute infective endocarditis.

METHODS: A total of 77 patients (mean age 49+/-9 years) operated on for acute endocarditis of the aortic valve was included in the study and analyzed retrospectively. The causative bacterium was isolated from blood cultures in 71 cases. Preoperatively, 21 patients required artificial ventilation and 24 had inotropic support due to hemodynamic instability. Aortic homografts were implanted in 43 patients, and mechanical valve prostheses in 34. The two patient groups were similar in terms of gender, age and preoperative inotropic support. In total, 31 patients (44%) had paravalvular abscesses, and a homograft was used significantly more often (77%, p <0.05) in these cases. Follow up examinations (clinical examination, ECG and transthoracic echocardiography) were performed six months postoperatively and continued on an annual basis. Endocarditis relapse was defined as persisting infection, whereas re-endocarditis indicated a new infection after an interval of at least six months.

RESULTS: Perioperative mortality was 11.5% (5/43) in homograft patients. In the 38 survivors, follow up was complete and averaged 5.0+/-1.2 years. One patient had an endocarditis relapse three months after surgery. Re-endocarditis occurred in three patients after two or three years. One other patient had pseudoaneurysm formation without a need for intervention, and one had repeat aortic valve replacement due to dysfunction of the graft after four years. The other 33 patients had an uneventful follow up. Echocardiography revealed aortic insufficiency grade 1 in 12 cases (36%), with no progression during follow up. Perioperative mortality in mechanicat valve patients was 20.5% (n = 7) (p <0.05 versus homograft), and in those with paravalvular abscess, perioperative mortality was even higher than in homograft patients (4/7, 57.1% versus 3/24, 12.5%; p <0.05). When considering only patients without paravalvular abscess, there was no significant difference between groups (10.5% versus 12.5%). Three relapses occurred in mechanical valve patients (10.3%), but no endocarditis recurred during follow up. One late death (3.7%) occurred due to bleeding complicating long-term anticoagulation.

CONCLUSION: The study results do not permit a general recommendation to be made for homograft use in patients with acute endocarditis. In cases with paravalvular abscesses, however, there was a trend towards improved outcome in the homograft group.