Background and Goal of Study: Nowadays, the most popular systems to evaluate the risk of mortality after a cardiac surgery (EuroSCORE, ACEF) take into account preoperative patient's parameters. As we think intraoperative factors may change the patient's risk profile, shouldn't be parameters recruited on the arrival at the intensive care unit (ICU) better to predict operative mortality in this kind of patients?
The goals of this study were
1) to find a relationship between general parameters of organ function on arrival at the ICU and patient's in hospital (90 days) mortality rate after a cardiac surgery and
2) to develop a new system to predict operative mortality after this kind of surgery.
Materials and Methods: We conducted a prospective study. 929 patients who had undergone a cardiac surgery were included.
We used logistic EuroScore and ACEF (using preoperative organ function parameters of patients) and APACHE II (using the 24 hour worst organ function parameters of patients) to predict patient's operative mortality risk. Several parameters recorded on the arrival at the ICU were explored looking for an univariate and multivariate association with in hospital mortality (90 days).
Results and Discussion: In-hospital mortality (90 days) was 9%. 6 of the parameters analyzed were considered to be independent factors of mortality. So this six postoperative parameters were included in the mortality risk model and conform our new system to predict in-hospital mortality risk profile (PCSS): Creatinine, mean arterial pressure, heart rate, troponin T, lactate and International Normalized Ratio (INR).
Our new system to predict operative mortality risk after a cardiac surgery was compared with 4 other systems for the same purpose. The best accuracy to predict in-hospital mortality was achieved by PCSS. The area under the ROC curve of the different systems analyzed were 0,890 (PCSS), followed by 0,768 (APACHE II), 0,754 (logistic EuroSCORE), 0,714 (standard EuroSCORE) and 0,699 (ACEF score).
Conclusion(s): Our new system to predict operative mortality risk of patients undergoing a cardiac surgery is better than others used for this purpose (APACHE II, logistic EuroSCORE, standard EUROSCORE, and ACEF score)