Understanding prosthesis patient mismatch in aortic valve replacement: from pitfalls to clinical impact.

Almost half a century ago, cardiac surgeons introduced the concept of prosthesis-patient mismatch (PPM), which was defined by indexing the effective orifice area (EOA) to body surface area. Although PPM has demonstrated strong prognostic value following surgical aortic valve replacement (SAVR), its significance in transcatheter aortic valve replacement (TAVR) remains uncertain. In this review, we revisit the concept of PPM and explore the methodological and clinical challenges in its application. Special focus is given to the limitations in interpreting EOA and indexed EOA (EOAi), including flow dependency and imaging variability. We also review the literature evaluating the association between PPM and clinical outcomes after SAVR and TAVR. Finally, we discuss a potential role of alternative metric such as the fitting index.