Emergency surgery for acute infective aortic valve endocarditis: performance of cryopreserved homografts and mode of failure.

Abstract

To describe our experience in the surgical treatment of infective, native and prosthetic aortic valve endocarditis, using cryopreserved homograft valves. Between January 1988 and September 1995, cryopreserved homografts were implanted in 49 patients (mean age 47 +/- 15 years; range 19-79) with acute infective endocarditis of the native (21/49; 43%) or the prosthetic (28/49; 57%) aortic valve. Aortic root abscesses were found in 39/49 (80%) patients, ventriculo-aortic disconnection in 27/49 (55%). An intracardiac fistula, originating from the left ventricular outflow tract was found in 25/49 (51%) patients. Indications for emergency surgery were congestive heart failure due to severe aortic valve regurgitation in 44/49 (90%) and systemic emboli in 5/49 (10%) patients. Preoperatively, 23/49 (47%) patients were in New York Heart Association (NYHA) class IV, and 5/49 (10%) were in acute circulatory failure. Mean left ventricular ejection fraction was 53 +/- 10% (25-65). Streptococci (27%) and staphylococci (27%) were the most important microorganisms found. The homograft was implanted as a scalloped freehand valve (34/49; 70%), as an intra-aortic inclusion cylinder (4/49; 6%) or as a free-standing root replacement (12/49; 24%). Combined procedures were necessary in 11/49 (22.5%) patients. Hospital mortality was 8.2% (4/49): 2/49 (4.1%) patients died from endocarditis-related sepsis, one (2%) from low cardiac output and one (2%) from a cerebrovascular accident. After a mean interval of 21 +/- 15 months (2-48), 9/45 (20%) patients had to be reoperated, all reoperations except one being homograft related. After a mean follow-up of 35 +/- 22 months (2-90), 4/44 (9%) patients had their homograft replaced by a mechanical prosthesis. After 5 years, actuarial freedom from late death was 97 +/- 3%; from late reoperation 69 +/- 9%; from late endocarditis 85 +/- 8%; and from late homograft degeneration 87 +/- 6%. Explanted homografts were acellular and non-vital, containing bacteria and/or leucocytes. B-lymphocytes were found in all and in one, T-cell lymphocytes were present. Emergency aortic valve replacement with cryopreserved homografts for acute native or prosthetic aortic valve endocarditis has a low operative mortality. The late incidence of recurrent endocarditis or homograft failure up to 7 years is acceptable. Cryopreserved homografts are non-viable. The presence of T-cell lymphocytes in explanted homografts indicates that rejection may be possible.