Mitroflow LXA structural deterioration following aortic valve replacement: a single-center experience.

Background: Concerns have been previously raised regarding the potential early degeneration of the Mitroflow (Sorin Group Italia, Saluggia, Vercelli, Italy) bioprostheses. We aimed to evaluate our clinical experience with the Mitroflow LXA prosthesis for aortic valve replacement.

Methods: We prospectively analyzed data from 227 consecutive patients (133 males, mean age 73.9±9.2 years) implanted with the Mitroflow LXA between February 2007 and October 2011. Follow-up data were obtained by contacting the referring cardiologists. Kaplan-Meier curves were constructed for all-cause mortality, valve related mortality and structural valve degeneration (SVD). Multivariable analysis was conducted to identify SVD predictors.

Results: Median follow-up time was 54.2±37.9 months and completeness of follow-up was 95%. Overall mortality in the entire series was at 31% (N.=71) and mortality from cardiac or unknown causes at 20% (N.=46). SVD occurred in 24 patients (10%) (median delay between implantation and diagnosis: 62.6 (36.5) months). Reintervention was required in 20 cases (13 redo surgery, 7 percutaneous transcatheter valve intervention). The 8 years actuarial global survival was 54.7±4.9%, freedom from valve related mortality 67.5±4.9% and freedom from SVD 72±8%. The estimated freedom from SVD was significantly (P=0.007) longer in larger prosthesis (diameter >21 mm, 77±11%) compared to the smaller devices (≤21 mm, 59±13%.). Multivariate analysis identified smaller prostheses and age at implantation as independent predictors of SVD.

Conclusions: The Mitroflow LXA showed evidence of early SVD in this cohort. A close follow-up of these patients is strongly advised.