The results show that the threshold of NT-proBNP on the first day after surgery is 871.8 pg / ml and in combination with EuroSCORE before surgery, the accuracy of diagnosing LCOS with EuroSCORE low - moderate risk (mostly medium risk) is 80.5%, with the EuroSCORE high risk 70%. With a threshold of NT-proBNP on the second day after surgery is 2516 pg / ml and and in combination with EuroSCORE before surgery, the accuracy of diagnosing LCOS with EuroSCORE low - moderate risk (mostly medium risk) is 77.9%, with the EuroSCORE high risk 66.7%.