Background:
Mitral valve surgery in older adults has substantial morbidity and mortality. While changes in operative techniques and post-operative care over time may lead to improved outcomes, there are currently a paucity of national surveillance data. The aims of our study were therefore to define trends in incidence, surgical technique, and mortality among patients undergoing mitral valve surgery.
Methods:
Inpatient Medicare standard analytic files were used to identify 100% of fee-for-service patients ≥65 years of age who underwent mitral valve surgery between 1999 and 2008. We constructed a denominator file from Medicare administrative data to report operative rates per 100,000 beneficiaries. Mortality (30-day and 1-year) was ascertained through corresponding vital status files. Surgery was classified as repair or replacement. Risk-standardized mortality rates were calculated using a multivariable model from Medicare claims data adjusting for medical comorbidities.
Results:
A total of 156,917 patients underwent mitral valve surgery during the study period. While the overall rate of mitral valve surgery per beneficiary remained relatively stable over time (1999: 136/100,000, 2008: 134/100,000), the proportion of patients ≥85 years of age increased (1999: 8.8%; 2008: 12.3%). The rate of mitral valve repair (vs. replacement) nearly doubled (1999: 24.7%; 2008: 46.8%). From 1999-2008, risk adjusted 30-day mortality decreased from 10.6% to 5.1% (OR 0.66; 95% CI, 0.60-0.71), a relative decline of 51.9%. Risk-adjusted one-year mortality decreased from 20.3% to 13.3% (OR 0.74; 95% CI, 0.69-0.78), a relative decline of 34.5%. Similar trends were seen across all age strata (Figure).
Conclusions:
From 1999-2008, despite an increase in the proportion of Medicare mitral valve surgery patients ≥85 years of age, postoperative risk-adjusted 30-day and one-year mortality decreased markedly across all age strata. Whether increasing rates of mitral valve repair or other management strategies are contributing factors deserves further investigation.