Medtronic freestyle aortic root bioprosthesis: Implant techniques

Background: The Medtronic Freestyle aortic root bioprosthesis is a complete porcine aortic root to allow implantation (1) as a subcoronary valve repla cement by removing graft sinus aorta, (2) as a cylinder with the sinotubula r junction intact within the aorta (root inclusion), or (3) as a complete a ortic root replacement. The choice among the three implant techniques depen ds on surgeon preference or upon the pathology encountered. The advantages and differences among the three implant techniques are examined. Methods: T he Medtronic Freestyle bioprosthesis was implanted in 1163 patients in a Fo od and Drug administration (FDA) clinical trial between August 1992 and Oct ober 1997. There were 21 centers in the international trial using a single data repository. Clinical data was collected prior to and at operation, at 3 to 6 months and annually. The data were compiled and statistical analysis performed at the data center. Results: Patients having subcoronary valve i mplants were older (80% > 65 years) and aortic occlusion time was about 20 minutes less than the other methods. Patients having aortic root replacemen t presented with more aortic valve insufficiency (20%). Pathology of the ao rtic root and ascending aorta requiring repair was 26%, and larger (27 mm) valves were used in 40% of patients. Risk of operation was lowest (5.0%) wi th subcoronary valve implants and highest (11.7%) with root replacement tec hnique. Thromboembolism was higher, early and late, with root inclusion (3. 0, 3.9%/patient per year) and root replacement (3.2, 3.0%/patient per year) than for subcoronary implants (1.8, 1.6%/patient per year). There were mor e patients taking warfarin at the 4-year point with root inclusion (20%) or root replacement techniques (24%) than among patients having subcoronary i mplants (14%). Explants of the valve occurred in 2% of patients, none of wh om had aortic root replacement. Conclusions: The Medtronic Freestyle biopro sthesis is an effective and versatile device for replacement of the aortic valve. It offers implant techniques that can treat the aortic root patholog y encountered at surgery and allows the operation to proceed according to s urgeon preference.