[The Mattone Outcome-BYPASS study: short-term outcome in patients undergoing coronary artery bypass graft surgery in Italian hospitals. Final results].

Background: In early 2008, a new national prospective study on short-term outcomes of coronary artery bypass graft (CABG) procedures started in Italy. The aim was to describe short-term results in patients undergoing CABG and improve methodologies for comparative outcome evaluation.
Methods: Only 26 Italian cardiac surgery centers participated in this survey. For each patient undergoing a CABG procedure, all centers were requested to provide specific data (type of procedure, hemodynamic conditions, comorbidities, recent myocardial infarction and unstable angina, ventricular function, emergency conditions, vital status at 30 days). Representativeness was tested by comparing characteristics of the enrolled population with information derived from national hospital discharge records. A multiple logistic regression analysis was used to perform indirect standardization; the mortality rate of the whole population was used as a reference standard. Comparison with the CABG model built on 34 310 patients in 2002-2004 was performed as well.
Results: The analysis of 7436 isolated CABG procedures showed a 30-day mortality of approximately 2%. The study population seemed to be representative of the Italian population of CABG patients. Using the new estimate model, two cardiac surgery centers showed significantly better risk adjusted mortality rates than the national reference standard, and two others showed significantly worse rates. The application of the "CABG model" yielded similar results.
Conclusions: Our study shows a high-quality level of Italian cardiac surgery centers and confirms the good applicability of the CABG model to the Italian CABG population. Comparison between results from the two models highlights the usefulness of regular outcome studies either for updating risk adjustment procedures and monitoring quality of care in Italian hospitals.