Aortic patient-prosthesis mismatch - does it matter? A review for cardiologists and cardiac surgeons

Patient-prosthesis mismatch (PPM) is the situation in which the area of an artificial valve is smaller than that of a healthy native valve it replaces. By this definition, all artificial valves demonstrate PPM, but large observational studies and several meta-analyses suggest that it is present in 30-50% of patients after surgical aortic valve replacement (SAVR). PPM has an impact on outcomes only when the indexed aortic valve area (AVAi) is ≤0.85cm2/m2 (moderate PPM) or 0.65cm2/m2 (severe PPM), particularly in patients with reduced LVEF. In transcatheter aortic valve replacement, the prevalence of PPM may be as low as 0.1%, and its impact on hard outcomes is not clear. We present a review of the relevant literature together with a framework for the differential diagnosis of increased pressure gradient and reduced area in prosthetic aortic valves and different strategies to reduce the risk of PPM with SAVR.