Risk stratification for open heart operations: Comparison of centers regardless of the influence of the surgical team

Plinio Pinna-Pintor, Marco Bobbio, Luca Sandrelli, Massimo Giammaria, Francesco Patané, Silvia Bartolozzi, Gianluigi Bergandi, Ottavio Alfieri

Research output: Contribution to journalArticlepeer-review


Background. Risk-adjusted mortality was previously used to compare institutions as a whole or surgeons. Because the same surgical team is working in two different hospitals, the aim of our study was to assess whether the institution can make a difference in surgical mortality. Methods. Preoperative data of 554 patients in institution A and 500 in institution B were prospectively collected during the same period of time. All patients were operated on by the same surgeon with the same first assistant and anesthesiology staff in both institutions. Patient population was stratified according to Parsonnet's predictive model, in five risk groups, and mortality was adjusted by the direct standardization method. Results. At institution A it was observed that in-hospital mortality was 2.3% (95% confidence interval, 1.3% to 4.0%), and in institution B 4.0% (95% confidence interval, 2.5% to 6.1%). The difference between the two mortality rates (1.7%; 95% confidence interval, -0.5% to 3.8%) is not statistically significant (p = 0.16), nor is the difference within each class. The standardized mortality ratio was 3.6% (95% confidence interval, 2.7% to 4.8%) and 5.8% (95% confidence interval, 4.6% to 7.2%), respectively. The difference of 2.2% (95% confidence interval, 0.5% to 3.8%) is statistically significant (p = 0.01). Conclusions. The institution can affect mortality of patients undergoing open heart operations, regardless of the influence of the surgical team.

Original languageEnglish
Pages (from-to)410-413
Number of pages4
JournalAnnals of Thoracic Surgery
Issue number2
Publication statusPublished - Aug 1997

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Surgery


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