Results of aortic valve replacement with pulmonary and aortic homografts

Background and aim of the study: Aortic valve replacement with cryopreserve d human pulmonary or aortic valves (homografts) is an attractive alternativ e to the implantation of mechanical valves or bioprostheses, as anticoagula tion can be avoided and a near-normal anatomy restored. However, few report s exist on the long-term follow up of patients with this type of valve. Methods: Between 1990 and 1997, a total of 64 homografts were implanted in 62 adults (mean age 42 +/- 12 years) with non-endocarditic valve lesions (i nsufficiency, n = 16; stenosis, n = 20; combined lesions, n = 12; redo, n = 16). In total, 23 pulmonary grafts (PG) and 41 aortic grafts (AG) were use d. Valves were obtained from the European Homograft Bank in Brussels. Two p atients with aortic homografts were lost to follow up; the others were exam ined clinically and echocardiographically at yearly intervals (mean 3.6 +/- 2.0 years). Children aged less than 16 years (n = 21), and patients receiv ing a homograft due to endocarditis (n = 28) or during a Ross procedure (n = 16) were excluded from the study. Results: Three patients (5%) died due to early postoperative complications (two with AG, one with PG). Three PG had to be explanted due to primary mal function, and five (total 35%) during further follow up due to severe aorti c insufficiency (at a mean of 3.3 +/- 1.8 years). In contrast, all AG were functioning at the end of the observation period (log rank test, p = 0.0001 , chi-square test 13.9). The mean echocardiographic degree of regurgitation for PG was significantly higher than for AG (2.2 +/- 1 vs. 0.75 +/- 0.7, p <0.0001). The peak transvalvular gradient did not differ between groups (F G 12.3 +/- 9 mmHg vs. AG 16.7 +/- 10 mmHg, p = NS). In respect of periopera tive parameters, patients with FG showed a significantly higher body temper ature during the first seven postoperative days (37.3 +/- 0.6 degrees C vs. 36.8 +/- 0.3 degrees C, p = 0.003). All three patients with acute graft ma lfunction in long-term follow up had a perioperative febrile response witho ut overt bacterial infection. Conclusion: In contrast to grafts of aortic origin, pulmonary homograft val ves should not be used for aortic valve replacement because of their high r ate of malfunction, both acutely and chronically. Higher postoperative body temperatures should lead to further investigations of possible enhanced im munoreactions against pulmonary homografts.