Structural Valve Deterioration of Bioprosthetic Aortic Valves: An Underestimated Complication
Résumé
OBJECTIVES: Structural valve deterioration (SVD) remains a major bioprosthesis-related complication, as recently described for the Mitroflow~valve (models LX and 12A) (LivaNova, London, United Kingdom). The real incidence of the SVD risk remains unclear, often due to methodologic pitfalls by systematically using the Kaplan-Meier estimator and/or the Cox model. In this report, we propose for the first time a precise statistical modeling of this issue. METHODS: Five hundred sixty-one patients who underwent aortic valve replacement with the aortic Mitroflow valve between 2002 and 2007 were included. We used an illness-death model for interval-censored data. Median follow-up was 6.6~years; 103 cases of SVD were diagnosed. RESULTS: The 4-year and 7-year SVD cumulative incidences after the first anniversary of surgery were 15.2% (95% confidence interval, 11.9-19.1) and 31.0% (95% confidence interval, 25.8-37.2), respectively. Female gender, dyslipidemia, chronic obstructive pulmonary disease, and severe patient-prosthesis mismatch were significant risk factors of SVD. The occurrence of SVD was associated with a 2-fold increase in the risk of death. CONCLUSIONS: Appropriate statistical models should be used to avoid underestimating the SVD complication associated with worse long-term survival.
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