Validity of identifying patient-prosthesis mismatch from the indexed effective orifice area.

The main problem that arises from patient-prosthesis mismatch after aortic valve replacement is a residual high transvalvular pressure gradient, resulting in left ventricular overload. It was demonstrated by Pibarot and Dumesnil that the indexed effective orifice area should be larger than 0.85-0.90 cm2/m2 to prevent any significant transvalvular pressure gradient after operation. However, we have encountered a higher residual transvalvular pressure gradient than expected in some patients with an aortic stented bioprosthesis with an indexed effective orifice area greater than 0.85 cm2/m2. Based on our data, an indexed effective orifice area of less than 1.25 cm2/m2 might be considered the threshold for patient-prosthesis mismatch in patients with a stented bioprosthesis because this indexed effective orifice area is associated with a low mean transvalvular pressure gradient (less than 10 mmHg). The practical implications include the necessity to consider the hemodynamic performance of each prosthesis type when seeking to define patient-prosthesis mismatch and abnormally or significant high postoperative gradients that lead to an increased left ventricular workload, so as to avoid residual significant transvalvular pressure gradients and higher rates of morbidity and mortality.