[The impact of the "patient - prosthesis mismatch" in patients with aortic valve replacement]

Abstract

Patient-Prosthesis Mismatch (PPM) is still a controversial matter in our days. We have PPM when the orifice area of an implanted aortic prosthesis valve is too small for the body surface area of an individual; this is, when the orifice area indexed to the body surface area is <0.8-0.9 cm2/m2.

Objective: Assess the impact of Patient-Prosthesis Mismatch in the short term and 2 years follow up in a group of patients submitted to aortic valve replacement.

Material and methods: The authors present a retrospective study involving 343 patients with a mean age of 64,68+/-12,4 years that were submitted to aortic valve replacement between January 2005 and December 2008. Data were collected from patients' files and direct contact with the patients, comparing the groups with and without PPM and correlating them in terms of Euroscore, demographics, type of implanted prosthesis, surgical times, ICU and hospital stay. The data related to short term and long term mortality as well as the NYHA class evolution were also obtained.

Results: Using the cut-off related to effective orifice area index 0,9 cm2/m2 we found PPM in 109 patients (31.7%). When comparing the two groups, we found that PPM seems to be related to advanced age (p=0.001), biological prosthesis (p=0.01) and, as expected, with use of valves less than 21 (p<0,05). A statistical significant difference was found for: 1) short-term mortality in patients with PPM (p<0,001), however, there were no differences in 2 years mortality and NYHA class between the groups; 2) aorta's cross clamping and extra corporeal circulation time (p=0.047 and p=0.036, respectively).