Surgical Treatment of Culture-Negative Aortic Infective Endocarditis

Background. We retrospectively analyzed the results of operations done for culture-negative aortic infective endocarditis at a single center over a period of 26 years. Methods. From June 1985 to January 2011, we operated on 82 patients with infective endocarditis of the aortic valve for which the results of culture were negative. Sixty-five of the patients (79.3%) were male and the patients' mean age was 38.0 +/- 14.4 years (range, 9 to 73 years). Nineteen of the patients (23.2%) had a history of previous cardiac surgery, and 16 of the patients (19.5%) had endocarditis of a prosthetic valve. Two patients (2.4%) had conduction blocks. The mean duration of follow-up was 7.1 +/- 4.3 years (range, 0.1 to 16.9 years), yielding a total of 477.0 patient-years for the study population. Results. One hundred and thirty-eight procedures were done on the 82 patients in the study. The most common procedure was aortic valve replacement, which was done on 67 patients (81.7%). Thirty-nine patients (47.6%) had concomitant procedures done on the mitral valve. Inhospital death occurred in 14 patients (17.1%). Postoperatively, 17 patients (20.7%) had a low cardiac output and 9 patients (11.0%) had heart block, of whom 3 required implantation of a permanent pacemaker. The actuarial rate of survival of the patient population at 1, 5, 10, and 15 years was 92.5% +/- 3.2%, 85.6% +/- 4.5%, 82.5 +/- 5.3%, and 72.2 +/- 10.7% respectively. Conclusions. Culture-negative infective endocarditis is a major problem in the diagnosis and treatment of a significant proportion of cases of endocarditis. Most of the affected patients are in a healed state, which could be a cause of negative culture results. In-hospital mortality in patients with culture-negative infective aortic endocarditis is associated with a history of previous cardiac surgery, whereas long-term mortality in this patient population is associated with nonaortic procedures. (Ann Thorac Surg 2012; 93:44-50) (C) 2012 by The Society of Thoracic Surgeons