Mitral valve replacement with the Hancock, Björk-Shiley and Lillehei-Kaster prostheses. A comparison based on a 15-year follow-up

Durability of Mitral Valve Bioprostheses: A Meta-Analysis of Long-Term Follow-up Studies

BACKGROUND

Porcine and pericardial valves exhibited similar freedom from structural valve deterioration after aortic valve replacement. Limited data exist regarding their durability at long-term follow-up in the mitral position.

METHODS

A literature search was performed through online databases. Papers reporting freedom from tissue valve deterioration after mitral valve replacement with a follow-up longer than 5 years were retrieved. Four porcine valves (Carpentier-Edwards [Edwards Lifesciences, Irvine, CA] and Hancock, Hancock II, and Mosaic [Medtronic, Inc, Minneapolis, MN]) and 1 pericardial prosthesis (Carpentier-Edwards) were the objects of the study. The structural valve deterioration (SVD) rate per year was calculated for each type of prosthesis. Kaplan-Meier curves and log-rank test analysis were performed to compare the long-term durability of porcine and pericardial valves.

RESULTS

Forty full-text papers including more than 15,000 patients were considered for the meta-analysis. Porcine valves were generally implanted in younger patients in the first period after their introduction. The mean age of the patients receiving a mitral bioprosthesis increased from 50 to 70 years over the decades. In patients operated after 1980 who had similar mean age at the time of implant, freedom from SVD was higher in the group of porcine valves with Mosaic prosthesis, showing the lowest rate of SVD. Long-term survival was higher for Mosaic porcine and Carpentier pericardial valves.

CONCLUSIONS

In surgical populations that underwent mitral valve replacement after 1980 with new generation tissue valves and similar mean age at the implant time, we found, at long-term follow-up, a higher freedom from SVD in the group of porcine prostheses.

The Carpentier-Edwards standard porcine bioprosthesis: clinical performance to 15 years

The Carpentier-Edwards standard porcine bioprosthesis was implanted in 1,195 patients in 1,213 operative procedures between 1975 and 1987, with the majority of implants performed prior to 1982 at the University of British Columbia. The mean age of the patient population was 57.2 years (range 8 to 85 years). The mean follow-up was 7.4 years per patient. The freedom from the combination of thromboembolism and antithromboembolic therapy-related hemorrhage at 15 years was 79.5% for aortic valve replacement (AVR), 72% for mitral valve replacement (MVR), and 84% for multiple valve replacement (MR) (p less than 0.05, AVR greater than MR greater than MVR). The freedom from structural valve deterioration at 15 years was 71% for AVR, 41% for MVR, and 41% for MR (14 years) (p less than 0.05, AVR greater than MVR greater than MR). The freedom from nonstructural dysfunction and prosthetic valve endocarditis did not distinguish the valve positions (p = NS). The freedom from valve-related mortality from all causes including reoperation was 92% for AVR, 78% for MVR, and 77% for MR at 15 years (p less than 0.05, AVR greater than MVR greater than MR). The freedom from residual morbidity was not significantly different between valve positions (p = NS). The freedom from treatment failure (valve-related mortality and residual morbidity) at 15 years was 87% for AVR, 72% for MVR, and 75% for MR (p less than 0.05, AVR greater than MR greater than MVR). The freedom from all complications at 14 years was 50% for AVR, 25% for MVR, and 27% for MR (p less than 0.05, AVR greater than MR greater than MVR).(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of type of prosthesis on late results after combined mitral-aortic valve replacement

The influence of type of prosthesis on the late outcome of patients with combined mitral-aortic valve replacement was analyzed by comparing, at a 14-year follow-up, patients receiving two biological prostheses (group 1; n = 135), two mechanical prostheses (group 2; n = 221), or a mechanical prosthesis in the aortic position and a bioprosthesis in the mitral position (group 3; n = 97). No difference was found among the three groups in terms of actuarial survival and incidence of and freedom from valve-related deaths, thromboemboli, and hemorrhages. Patients with biological prostheses had a significantly greater incidence of structural valve deterioration, reoperations, and overall complications when compared with patients with only mechanical prostheses. The results of an extended follow-up of patients with combined mitral-aortic valve replacement indicate that mechanical prostheses perform better in the long-term owing to their superior durability when compared with biological valves. The use of bioprostheses should be confined to old patients with limited life expectancy because of their cardiac disease, provided that anticoagulants are not used. Combination of mechanical and biological prostheses in the same patient should be avoided because the advantages of each type of prosthesis are lost.