Unstented and Partial Stented Bioprostheses for Aortic Valve Replacement-Up to 6 Years of Follow-Up

Abstract

Since January 8,1985, three different designs of unstented (type A, n = 9) and partial stented (type B, n = 4; and type C, n = 3) glutaraldehyde preserved porcine aortic valves were used for aortic valve replacement in 16 patients with acquired aortic valve lesions. Type A and type B prostheses were Implanted using a two suture row technique. In type C prostheses, only a single suture row was necessary for implantation, facilitating surgery considerably. In all patients, the fully flexible commissures of the bioprostheses were secured to the aortic wall of the recipient. There was no hospital mortality. Two patients with type A bioprostheses died due to noncardiac causes, 4 and 24 months postoperatively. One bioprosthesis in this group had to be replaced after 3 months because of insufficiency. Serial Doppler echocardiographic studies were performed up to 6 years after implantation. No significant leaflet calcification was observed. In three type A bioprostheses, a mild insufficiency without progression was recorded. The latest mean/peak transprosthetic pressure gradients were: type A: 6 ± 4 mmHg/12 ± 6 mmHg; type B: 6 ± 3 mmHg/14 ± 5 mmHg; and type C: 11 ± 5 mmHg/18 ± 8 mmHg. The functional results of the type A and type B bioprostheses have proven to be satisfactory. The slightly higher pressure gradients in patients with a type C bioprosthesis give rise to further refinements of its design. These results confirm the usefulness of imitating normal anatomy by using unstented or partial stented bioprostheses.

Técnica simplificada de implante de bioprótese aórtica sem suporte ("stentless")

“…Após essa experiência pioneira, pouco se difundiu em relação à utilização das biopróteses aórticas "stentless", provavelmente pela sua maior complexidade de implante, quando comparada às biopróteses convencionais e próteses mecânicas (7,8,13) . Várias técnicas têm sido propostas para o seu implante -posicionamento subcoronário, técnica de inclusão de raiz aórtica, substituição total da raiz da aorta -necessitando, na maioria das vezes, dois planos completos de sutura e/ou reimplante dos óstios coronarianos (18)(19)(20)(21)(22) . Na presente padronização, utilizou-se um plano de sutura com pontos separados na altura do anel aórtico e suspensão dos pilares com sutura contí-nua, com posicionamento subcoronário da biopró-tese.…”