Actuarial versus actual freedom from structural valve deterioration with the Carpentier-Edwards porcine bioprostheses

BACKGROUND: The clinical performance of porcine bioprostheses for valve replacement surgery has been evaluated for over three decades by actuarial analysis as the standard for reporting time related results. The incidence of structural valve deterioration (SVD) is used for the selection of prostheses for various subsets of patients. Actual or cumulative incidence analysis may provide a superior method to determine durability of bioprostheses. OBJECTIVE: To compare actuarial versus actual methodology in determining the durability of porcine bioprostheses for aortic (AVR) and mitral valve replacement (MVR). PATIENTS AND METHODS: Carpentier-Edwards porcine bioprostheses were implanted between 1975 and 1995 in 2237 AVR and 1582 MVR. The mean age for AVR patients was 65.4 +/- 12 years and for MVR patients 61.7 +/- 12 years. The cumulative follow up for AVR was 14,810 years (mean 6.6 +/- 4.7) and for MVR 9718 years (mean 6.1 +/- 4.5). RESULTS: For AVR the actual freedom from SVD was 87.4 +/- 2.0% and 95.6 +/- 1.8% in those aged 61 to 70 years and more than 70 years, respectively; the actuarial freedom was 75.9 +/- 4.2% and 82.3 +/- 7.9%, respectively. For MVR the actual freedom from SVD was 69.4 +/- 2.5% and 92.9 +/- 1.9% for those aged 61 to 70 years and more than 70 years, respectively; the actuarial freedom was 25.5 +/- 5.7% and 79.5 +/- 6.0%, respectively. Predictors of freedom from SVD for AVR were identified as advancing age, falling into the age groups 61 to 70 and those older than 70 years, and intermediate valve sizes; predictors for MVR were advancing age and age older than 70 years. CONCLUSIONS: Comparison of methods of durability assessment revealed that actual freedom from SVD supports porcine bioprostheses for AVR in patients more than 60 years of age and for MVR in patients more than 70 years of age. This evaluation with experience to 15 years supports the indications for use of porcine bioprostheses. (Pour le resume, voir page 974).