Patient-prosthesis mismatch: surgical aortic valve replacement versus transcatheter aortic valve replacement in high risk patients with aortic stenosis.

Patient prosthesis mismatch (PPM) can occur when a prosthetic aortic valve has an effective orifice area (EOA) less than that of a native valve. A recent study by Zorn and colleagues evaluated the incidence and significance of PPM in high risk patients with severe aortic stenosis who were randomized to transcatheter aortic valve replacement (TAVR) or surgical aortic valve replacement (SAVR). TAVR is associated with decreased incidence of severe PPM compared to traditional SAVR valves. Severe PPM increases risk for death at 1 year postoperatively in high risk patients. The increased incidence of PPM is largely due to differences in valve design and should encourage development of newer SAVR valves to reduce risk for PPM. In addition more vigorous approaches to root enlargement in small annulus should be performed with SAVR to prevent PPM.