Early Structural Valve Deterioration of Mitroflow Aortic Bioprosthesis: Mode, Incidence and Impact on Outcome in a Large Cohort of Patients
Background—Structural valve deterioration (SVD) is a major flaw of bioprostheses. Early SVD has been suspected in the last models of Mitroflow bioprosthesis. We sought to assess the incidence, the mode and the impact of SVD on outcome in a large series of Mitroflow aortic valve replacement (AVR).
Methods and Results—617 consecutive patients (76.1±6.3 years) underwent AVR with a Mitroflow prosthesis (models 12A/LX) between 2002 and 2007. By echocardiography, 39 patients developed early SVD (1.66% per patient-year), mainly on a stenosis mode (n=36). Mean delay to SVD was only 3.8±1.4 years and five-years SVD-free survival was 91.6%[95%CI 88.7-94.7] for the whole cohort, 79.8%[71.2-89.4] and 94.0%[90.3-97.8] for 19 and 21 mm sizes, respectively. Among the 39 SVD, 13 patients (33%) had an accelerated SVD once mean gradient exceeded 30mmHg. Valve-related death was 46.2% in this SVD subgroup. Five-years overall survival was 69.6%[65.7-73.9]. In multivariable analysis SVD was the strongest correlate of overall mortality (HR=7.7; [95% CI;4.4-13.6]).
Conclusions—Early SVD is frequent in Mitroflow bioprosthesis (models 12A/LX), especially for small sizes (19 and 21 mm) and reduces overall survival. An unpredictable accelerated pattern of SVD constitutes a life-threatening condition. In view of the large number of Mitroflow valves implanted worldwide, one can expect an epidemic of SVD and valve-related deaths, which represents a major public health issue, especially in the elderly. Hence, a close follow-up with yearly echocardiography after Mitroflow implantation is advisable. An urgent redo surgery should be discussed in patients with severe SVD even though still asymptomatic.
- structural valve disease
- survival analysis
- cardiac valvular surgery
- aortic stenosis
- Received March 31, 2014.
- Revision received September 8, 2014.
- Accepted September 18, 2014.