Abstract 9744: Declining Relative Use of Mitral Valve Repair in Australia Despite Superior Outcomes: A Statewide Population-linkage Study

Abstract

Introduction: Mitral valve (MV) repair (MVr) has superior survival outcomes to MV replacement (MVR) for primary MV diseases. MVr cases has increased in other developed nations but is unknown in Australia. We assessed temporal trends in the total and relative MVr volume and compared MVr and MVR outcomes over 17 years. Method: Patients who had isolated MV surgery (MVSx) between 2001-2017 were identified from the New South Wales statewide Admitted Patient Data Collection registry. Mortality outcome was tracked to Dec 2018. Results: A total of 5693 patients (MVr: n=2020 [35%]; mechanical MVR: n=1656 [29%]; bioprosthetic MVR: n=2017 [35%]) were identified; median age [interquartile range] were 67y [59-75y] vs 64y [55-71y] vs 75y [68-80y], respectively (all P<0.001). Median follow-up for the cohort was 6.3yrs. Annual MVSx cases increased over the study period but relative use of MVr declined from 44% (110/252 MVSx) in 2002 to 27% (165/601 MVSx) in 2017 (Fig1). Crude in-hospital and 1-yr mortality steadily declined for all groups between 2001 and 2017. MVr had the best outcome, with 1.2% in-hospital, 2.5% 1-yr, and 21.6% total cumulative mortality. Compared to MVr, after adjusting for age, sex, referral source, and comorbidities, the adjusted hazard ratios for long-term mortality were 1.41 (95% confidence interval [CI]=1.24-1.61) for mechanical MVR and 1.73 (95% CI=1.53-1.95) for bioprosthetic MVR (Fig 2). Conclusion: In this statewide Australian cohort study, relative use of MVr decreased over 17 years and are lower than reported by other international studies, despite having superior outcome compared to MVR. Factors driving the relatively low use of MVr should be explored.