New Bioprostheses for Aortic Valve Replacement
tissue stress. The new stentless bioprostheses have already been shown to have improved flow characteristics, resulting in better left ventricular mass regression post operatively. Ultimately, the decreased tissue stress in the more natural stentless valve may also translate into improved late durability.
The stentless porcine Freestyle Bioprosthesis (Medtronic, Inc.) has the added advantage of being treated with the AOA process (AOA is a registered trademark of Biomedical Design, Inc., Atlanta, GA). The AOA treatment process will eventually be used in both stented and stentless valves in the future. Overall, with these new engineering developments, tissue valves now appear to offer decreased valve-related morbidity in an easily implantable prosthesis, which is available to every surgeon.
| Follow-up data from clinical trials and newer second-generation bioprostheses have begun to demonstrate improvements and better freedom from late valve-related complications with these new prostheses than with the older generation of tissue valves. The second generation tissue valves have performed extremely well clinically. These valves utilize a low-pressure tissue fixation process. Poirier reported similar findings in 598 patients undergoing aortic valve replacement with the Perimount pericardial valve.(12) The 10-year freedom from valve degeneration was 93% and from thromboembolism, 92%. In this series, no primary tissue failure occurred in any patient over 70 years of age, highlighting the advantages of tissue valves in the geriatric population. To summarize, encouraging results with new second-generation tissue valves are showing improvements and a low risk of valve-related complications. Based on these results, it is almost certain that the use of tissue valves will increase over the next few years. Looking ahead, the introduction of stentless valves and the third and fourth generations of tissue valves offers even greater promise. The concept of a stentless bioprosthesis has resulted in a more natural valve with improved hemodynamics and less artificial |
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The stentless porcine Freestyle Bioprosthesis (Medtronic, Inc.) has the added advantage of being treated with the AOA process (AOA is a registered trademark of Biomedical Design, Inc., Atlanta, GA). The AOA treatment process will eventually be used in both stented and stentless valves in the future. Overall, with these new engineering developments, tissue valves now appear to offer decreased valve-related morbidity in an easily implantable prosthesis, which is available to every surgeon.