Durability of the Mitroflow Pericardial Prosthesis: Influence of Patient-Prosthesis Mismatch and New Anticalcification Treatment.

BACKGROUND:  The Mitroflow pericardial bioprosthesis (MPB) has been recently associated with a high incidence of early structural failures, questioning its validity as cardiac valve substitute. We have therefore reviewed our experience with this device.

MATERIALS AND METHODS:  A total of 398 patients with a mean age of 75 ± 7 years (58% above the age of 75 years) had aortic valve replacement with a Mitroflow prosthesis (2005-2015). Most patients had calcific aortic stenosis (86%) and were in sinus rhythm (89%). Mean EuroSCORE II was 5.5 ± 6.2. Mean follow-up was 4 ± 2 years (range: 4 months to 10 years), which was 100% complete.

RESULTS:  Hospital mortality was 6.5%; at discharge, 25% of patients had a moderate patient-prosthesis mismatch and none had a severe mismatch. Cumulative incidence of structural valve deterioration in the entire series was 2% (95% confidence interval [CI]: 1-4) at 5 years and 7% (95% CI: 4-14) at 8 years. Significant factors influencing MPB durability were age ≤ 65 years ( p  < 0.001) and the presence of patient-prosthesis mismatch ( p  = 0.01). No cases of structural valve deterioration were observed in patients with the new prosthetic model incorporating an anticalcification treatment the first 4 years of follow-up.

CONCLUSIONS:  The Mitroflow prosthesis has shown satisfactory results in the first decade of use. Durability appears adversely influenced by patient age and patient-prosthesis mismatch. Thus, a careful valve size selection and implantation in patients >65 years of age appears to be associated with excellent valve durability in the aortic position. Whether the new anticalcification treatment will provide a more durable prosthesis must be verified at a longer follow-up.