Is Prosthesis–Patient Mismatch a Clinically Relevant Entity?

Abstract

In this issue of Circulation , Koch and associates1 from the Cleveland Clinic published a study on the relationship between prosthetic valve size and the Duke Activity Status Index (DASI) after aortic valve replacement (AVR). The study was conducted with 1014 patients operated on from 1995 through 1998, completed 1 year later, and published now. DASI scores increased from a mean of 29 preoperatively to 46 postoperatively after a mean follow-up of 8.3 months. The investigators could find no obvious relationship between prosthetic valve size and postoperative DASI score. One of the limitations of the study was that prosthetic valve gradients and effective orifice areas were not measured by echocardiography to quantify prosthesis–patient mismatch. It is also interesting to note that more than two thirds of the patients were in New York Heart Association functional classes I and II preoperatively, and yet the DASI mean score before surgery was only 29 out of a maximum of 58.2. For this reason alone, it must be assumed that factors other than the aortic valve disease played a role in the DASI score. Nevertheless, this is not the first study to suggest that valve size plays no role in the clinical outcomes of AVR. See p 3221 Valve prosthesis–patient mismatch (PPM) is a term introduced by Rahimtoola in 1978 to describe a condition in which the in vivo prosthetic valve effective orifice area is smaller than that of the native valve.2 According to this broad definition, every patient with a prosthetic heart valve has PPM because the leaflets of both mechanical and bioprosthetic valves are mounted into frames that occupy …