Patient-prosthesis mismatch can be predicted at the time of operation

Background. Patient-prosthesis mismatch is a frequent cause of high postope rative gradients in normally functioning prostheses. The objective of this study was to determine whether mismatch can be predicted at the time of ope ration. Methods. Indices used to predict mismatch were valve size, indexed internal geometric area, and projected indexed effective orifice area (EOA) calcula ted at the time of operation, and results were compared with indexed EOA an d mean gradients measured by Doppler echocardiography after operation in 39 6 patients. Results. The sensitivity and specificity of these indices to detect mismatc h, defined as a postoperative indexed EOA of 0.85 cm(2)/m(2) or less, were respectively: 35% and 84% for valve size, 46% and 85% for indexed internal geometric area, and 73% and 80% for projected indexed EGA. Projected indexe d EOA also correlated best with resting (r = 0.67) and exercise (r = 0.77) postoperative gradients. Conclusions. The projected indexed EOA calculated at the time of operation accurately predicts mismatch as well as resting and exercise postoperative gradients, whereas valve size and indexed internal geometric area cannot be used for this purpose. (C) 2001 by The Society of Thoracic Surgeons.