Expected and Observed Mortality in Patients Undergoing Coronary Artery Bypass Surgery

Abstract

Anahtar Kelimeler: Mortalite; koroner arter baypas ABSTRACT Objective: The aim of this study is to investigate the expected mortality rates calculated with EuroSCORE II and observed mortality rates in patients undergoing coronary artery bypas surgery (CABG). Material and Methods: Patients who underwent CABG surgery in 2010 and 2011 in our clinic were included in this study. In this descriptive retrospective study, hospital database and patient files were scanned to obtain patients' data. We conducted post-discharge follow-up by phone calls. Results: Four hundred fifty-five patients who matched the criteria were included in this study. Mean age of the patients was 61.4±11.1 years and 94 (20.7%) of the patients were female. Sixteen (3.5%) patients were octogenarians. One hundred eighty-seven (41.1%) patients defined CCS Class IV angina and 22 (4.8%) were in NYHA class IV functional capacity. Expected mortality rate was 3.5% (95% CI=3.0-4.0) and observed mortality rate was 3.1% (95% CI=1.5-4.7), and did not reveal a significant difference. According to EuroSCORE II, the area under ROC curve was 0.840 (95% CI= 0.747-0.933, p=0.000), and represented an excellent test. Calibration was tested with HomerLemeshow goodness of fit test (x²=15.872, df: 8, p= 0.044) and evaluated as not good. Conclusion: The observed mortality in this group of patients is relevant to expected mortality rate calculated with EuroSCORE II. The discrimination power of EuroSCORE II mortality risk model is excellent, but the calibration is not good. We recommend EuroSCORE II as a criterion for CABG surgery mortality risk modeling.