Operations were conducted for the second time on 87 patients (98 operations). Reoperations were performed on 75 (76.5%) and closure of the fistula in 23 (23.5%) patients. The outcome of the operation was appraised according to the clinical course: without sepsis and with prosthetic septic endocarditis, respectively, in 57 (65.5%) and 30 (34.5%) cases. It was found that survival was lower among patients with prosthetic septic endocarditis than among those without sepsis, 37.9% and 53%, respectively. The position of the prosthesis determined the time of the development of the complication, both in fistulas and in thromboses. Disturbances in the function of the prosthesis occur mainly in the first postoperative months in patients without sepsis and in the first months and the late-term periods after surgery in patients with prosthetic septic endocarditis.