Patient-prosthesis mismatch: the Japanese experience.

The concept of patient-prosthesis mismatch (PPM) was defined as existing "when the effective prosthetic valve area, after insertion into the patient, is less than that of a normal valve". However, based on the correlation between the mean transvalvular pressure gradient and the corrected effective orifice area (EOA), PPM is currently defined as an EOA corrected by a body surface area (BSA) of <or=0.85 cm(2)/m(2). The surgical procedure will differ for each patient, not only because of variations in the size of the aortic annulus, but also because of the patient's age, sex, level of activity, level of motivation, and complications. However, minimizing the risk of PPM must always be considered by selection of appropriate surgical strategies, including aortic root enlargement, use of a supra-annular or high performance prosthesis, and the use of a stentless bioprosthesis, aortic homograft, or pulmonary autograft. We reviewed our results for aortic valve replacement (AVR) for 1991-2002, when we routinely performed aortic root enlargement in patients >65 years old, while supra-annular implantation of a bioprosthesis was done in patients >or=65 years old with a small aortic annulus. We discuss our present strategy after the introduction of a new high performance prosthesis, since the EOAs are dramatically increased.