Prosthesis-Patient Mismatch After Transcatheter Aortic Valve Replacement

T he purpose of aortic valve replacement (AVR) is to replace the severely dysfunctional native valve with a prosthetic valve that ideally has no residual stenosis or regurgitation. However, the hemodynamics of most prosthetic valves are often inferior to that of the normal native valve, and a significant proportion of patients undergoing AVR have high residual transprosthetic pressure gradients due to prosthesis–patient mismatch (PPM). PPM refers to a prosthetic valve that is functioning normally but whose effective orifice area (EOA) is too small in relation to the patient’s body surface area and thus to cardiac output requirements. PPM is thus defined on the basis of the prosthetic valve EOA indexed to the patient’s body surface area, and it is considered absent or not clinically significant when the indexed EOA (EOAi) is >0.85 cm/m, moderate when it is between 0.65 and 0.85 cm/m, and severe when <0.65 cm/m (1). In a meta-analysis conducted by Head et al. in 2012 (2), severe PPM occurred in 9.8% of patients following surgical aortic valve replacement (SAVR) and was associated with a 1.84-fold increase in mortality (Figure 1). Earlier this year, Fallon et al. (3) reported the data of 59,779 patients $65 years of age who underwent isolated SAVR between 2004