Abstract 3444: Patient-Prosthesis Mismatch After Mechanical Mitral Valve Replacement Does not Affect Long-term Survival but has an Impact on Functional Status
Background: Definition and incidence of Patient-Prosthesis Mismatch (PPM) in the mitral position are unclear. This study was conducted to determine the impact of PPM on late survival and functional status after MVR with a mechanical valve.
Methods: Between 1992 and 2005, 711 patients, mean age 60±10 years underwent a mechanical valve replacement with either St-Jude (294) or CarboMedics (416) valve. There were 52 concomitant procedures (50 tricuspid annuloplasties, 25 PFO closures and 20 radiofrequency mazes). Mean clinical follow-up was 4.4±3.3 years. Statistics for PPM were done with cutoff values for EOAi <1.2 cm2/m2, <1.3 cm2/m2 and <1.4 cm2/m2. Parametric and non-parametric tests were used to determine predictors of outcome.
Results: Prevalence of PPM was 5%, 10% and 23% when considering values of <1.2 cm2/m2,<1.3 cm2/m2 and <1.4 cm2/m2 respectively. When considering functional amelioration (defined as 1 or 2 or 3 NYHA functional class amelioration) patients with an EOAi >1.4 cm2/m2 had a better outcome than patients with EOAi<1.4 cm2/m2 (OR: 1.98; p<0.03) when adjusted for age and sex. There was only a trend toward decreased long-term survival in patients with EOAi <1.2 cm2/m2: survival with and without PPM at 1, 3, 5 and 10 years was 92% vs 82%, 88% vs 80%, 85% vs 76% and 72% vs 71% respectively. Defining PPM as EOAi <1.3 cm2/m2, survival of patients without PPM versus patients with PPM at 1, 3, 5 and 10 years was 92% vs 89%, 88% vs 84%, 84% vs 78% and 73% vs 72% respectively (NS). Survivals were similar using EOAi <1.4 cm2/m2.
Conclusions: In a large cohort of patients undergoing MVR with mechanical prostheses, we could not find a significant influence of PPM on long-term survival. PPM defined as EOAi <1.2 cm2/m2 was observed in only 5% of patients. Patients with an EOAi >1.4 cm2/m2 had a better improvement in their functional status.