Does Hospital Volume Impact Rates of Mitral Valve Repair and Mortality Post Mitral Valve Surgery in the Elderly?

Journal Wrap | While most hospitals perform few mitral valve operations on elderly patients, a greater volume of mitral procedures is associated with higher repair rates, according to new research published in the Journal of Thoracic Cardiovascular Surgery. In addition, both greater volume of mitral procedures and increasing mitral repair rates were associated with decreased mortality.

Using Medicare Provider Analysis and Review (MEDPAR) and corresponding Beneficiary Annual Summary Files (BASF), the study looked at all Medicare beneficiaries aged ≥65 years who underwent mitral valve repair or replacement from 2000 through 2009. Patients with significant concomitant procedures or other nonvalvular procedures were excluded, as were patients with <12 months of Medicare Part A and Part B coverage in the year preceding their index admission, and patients with emergency admissions. The Vital Status file for February 2012 was used to calculate long-term survival.

Overall results found that of 1,239 hospitals performing mitral valve surgery on Medicare beneficiaries from 2000 through 2009, only 9% of hospitals performed >40 mitral operations per year, 29% performed ≤5, and 51% performed ≤10. Mitral repair rates were low: 22.7% of hospitals performed ≤1, 65.1% performed ≤5, and only 5.6% performed >20 mitral repairs per year in those aged ≥65 years. Repair rates increased with increasing volume of mitral operations per year: ≤5, 30.5%; 6-10, 32.9%; 11-20, 34.9%; 21-40, 38.8%; and >40, 42.0% (p = 0.0001).

In terms of mortality, hospitals with lower volume had significantly higher adjusted operative mortality compared with hospitals performing >40 cases per year: ≤5 cases per year, odds ratio (OR) 1.58 (95% confidence interval [CI], 1.40-1.78); 6-10 cases per year, OR 1.29 (95% CI, 1.17-1.43); 11-20 cases per year, OR 1.17 (95% CI, 1.07-1.28); 21-40 cases per year, OR 1.15 (95% CI, 1.05-1.26). Hospitals with lower mitral repair rates had an increased likelihood of operative mortality relative to the top quartile: lowest quartile, OR 1.31 (95% CI, 1.20-1.44); second quartile, OR 1.18 (95% CI, 1.09-1.29); and third quartile, OR 1.14 (95% CI, 1.05-1.24). Long-term mortality beyond 6 months was also higher in low-volume hospitals: ≤5 cases year, hazard ratio 1.11 (95% CI, 1.06-1.18); 6-10 cases per year, OR 1.06 (95% CI, 1.02-1.10) compared with hospitals performing >40 cases per year.

“This is not the first study that demonstrates a relationship between mitral surgical volume and rates of mitral valve repair,” notes David S. Bach, MD, in an ACC Journal Scan. “As with some earlier studies, this study also shows an effect between volume and mortality: higher mitral surgical volume and higher rates of mitral repair both were associated with decreased mortality rates. These data give further weight to the current American Heart Association/American College of Cardiology guideline recommendations that many patients with heart valve disease are best served in a Center of Excellence.”


  1. Vassileva CM, McNeely C, Spertus J, et al. J Thorac Cardiovasc Surg. 2015;149:762-68.

Clinical Topics: Valvular Heart Disease

Keywords: CardioSource WorldNews Interventions, Confidence Intervals, Heart Valve Diseases, Hospital Mortality, Infarction, Mandatory Reporting, Medicare, Mitral Valve, Outcome Assessment, Health Care, Patient Readmission, Patient Selection, Registries

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