Early Structural Valve Deterioration of the Mitroflow Aortic Bioprosthesis

There has been a trend toward more frequent use of bioprosthetic valves, especially in the young generations, over the last decade.1,2 According to the Society of Thoracic Surgeons database, use of bioprosthetic valve increased from 44% in 1996 to 78% in 2006 in North America.1 Freedom from warfarin use and restrictions on diet and activities make bioprosthetic valves more attractive and popular, and multiple reports have shown that choosing a bioprosthetic valve does not decrease survival despite the increased rate of reoperation.3,4Article see p 2012The Mitroflow aortic prosthesis (Sorin Group Inc) is one of the most frequently used bioprostheses, with >100 000 implanted worldwide.5 The bovine pericardium is mounted externally around the stent, which maximizes the flow relative to the stent size. The valve is placed in the supra-annular position compared with the intra-annular position in some of the other bioprostheses. These characteristics allow superior valve hemodynamics in the Mitroflow aortic valve, especially in those with a small aortic annulus (19 and 21 mm)6; therefore, the Mitroflow aortic valve is considered an ideal valve for patients with a small aortic root.The Achilles heel of the bioprosthetic valve is structural valve deterioration (SVD). Cusp tears and thickening, calcification, pannus formation, and thrombus lead to deterioration of the valve,7 which is the leading reason for reoperation in bioprosthetic valves. The rate of SVD differs among ages; valves implanted in younger patients degenerate faster. For patients >65 years of age, the 10-year freedom from SVD in new pericardial valves is typically >90%.8In this issue of Circulation , Senage et al9 strike a note of warning …