Inaccuracy of Prediction of Mitral Valve Prosthesis Size

Abstract

Several formulae related to body surface area have been proposed to predict normal mitral annular size. This study examined the applicability of such formulae in predicting the size of mitral valve prostheses. Developmental criteria and echocardiographic parameters were used retrospectively to determine mitral annular size in 92 consecutive patients undergoing mitral valve replacement. Discrepancies were noted among the different predicted annular diameters. Moreover, predicted diameters differed from the diameters of the implanted prostheses. These differences were not influenced by type of prosthesis, type of lesion, technique of surgery, or sex of the patient. A greater degree of disparity was noted for larger body surface areas with all prediction formulae. However, valve size index and valve area index remained incremental with increasing prosthesis size. It was concluded that prediction formulae for mitral annular size based on body surface area do not help the surgeon to predetermine the size of mitral valve prosthesis that may be implanted at operation.