Treatment of complicated prosthetic aortic valve endocarditis with annular abscess formation by homograft aortic root replacement. The outcome of 30 consecutive patients with active aortic prosthetic valve endocarditis and root abscesses treated by the technique of homograft aortic root replacement with reimplantation of the coronary arteries is detailed. The principles of this technique are the removal of all abscesses and infected areas likely to drain into the infected mediastinum, excision of infected tissues down to healthy noninfected tissue and replacement with an antibiotic-impregnated homograft aortic root. All patients had evidence of progressive cardiac failure and ongoing sepsis. Mean patient age (+/- SD) at the time of operation was 42 +/- 18 years. The mean number of previous aortic valve replacements per patient was 1.6 +/- 0.7; 14 patients (47%) had undergone greater than or equal to 2 previous replacements. At operation, aortic root abscesses were found in all patients; abscess extension to adjacent structures and partial valve dehiscence had occurred in 23. In-hospital death occurred in 9 (30%) of the 30 patients. The 21 hospital survivors have been followed up for a mean of 66 +/- 42 months (range 9 to 144). Overall, 17 (81%) of the 21 hospital survivors have remained free of major adverse events (recurrence of endocarditis, need for reoperation or death). The results of our study suggest that homograft aortic root replacement should be considered favorably in the treatment of patients with aortic prosthetic valve endocarditis and root abscesses. 