Machine-learning predictions for acute kidney injuries after coronary artery bypass grafting: a real-life muticenter retrospective cohort study.

BACKGROUND: Acute kidney injury (AKI) after coronary artery bypass grafting (CABG) surgery is associated with poor outcomes. The objective of this study was to apply a new machine learning (ML) method to establish prediction models of AKI after CABG. METHODS: A total of 2,780 patients from two medical centers in East China who underwent primary isolated CABG were enrolled. The dataset was randomly divided for model training (80%) and model testing (20%). Four ML models based on LightGBM, Support vector machine (SVM), Softmax and random forest (RF) algorithms respectively were established in Python. A total of 2,051 patients from two other medical centers were assigned to an external validation group to verify the performances of the ML prediction models. The models were evaluated using the area under the receiver operating characteristics curve (AUC), Hosmer-Lemeshow goodness-of-fit statistic, Bland-Altman plots, and decision curve analysis. The outcome of the LightGBM model was interpreted using SHapley Additive exPlanations (SHAP). RESULTS: The incidence of postoperative AKI in the modeling group was 13.4%. Similarly, the incidence of postoperative AKI of the two medical centers in the external validation group was 8.2% and 13.6% respectively. LightGBM performed the best in predicting, with an AUC of 0.8027 in internal validation group and 0.8798 and 0.7801 in the external validation group. The SHAP revealed the top 20 predictors of postoperative AKI ranked according to the importance, and the top three features on prediction were the serum creatinine in the first 24 h after operation, the last preoperative Scr level, and body surface area. CONCLUSION: This study provides a LightGBM predictive model that can make accurate predictions for AKI after CABG surgery. The LightGBM model shows good predictive ability in both internal and external validation. It can help cardiac surgeons identify high-risk patients who may experience AKI after CABG surgery.

Predictive ability of EuroSCORE II integrating cardiactroponin T in patients undergoing OPCABG.

BACKGROUND: Preoperative risk evaluation systems are significant and important to the allocation of medical resources and the communication between doctors and patients. The European System for Cardiac Operative Risk Evaluation II (EuroSCORE II) is widely used in clinical practice. Cardiac troponin T (cTnT) can specifically and accurately reflect myocardial injury. Whether EuroSCORE II can improve the predictive power after integrating with cTnT is still unclear. This study was a retrospective single center study designed to assess the predictive ability of EuroSCORE II integrated with cTnT for patients undergoing isolated off-pump coronary artery bypass grafting (OPCABG). METHODS: This retrospective and observational cohort study included 1887 patients who underwent first isolated OPCABG. cTnT was detected within 48 h before operation in each patient. According to myocardial injury, patients were divided by cTnT into 4 stages. A new risk evaluation system was created through logistic regression with EuroSCORE II and myocardial injury classification as covariates. Then the two risk evaluation systems were comparatively assessed by regression analysis, receiver operator characteristic curves, net reclassification index, Bland-Altman plots and decision curve analysis. RESULTS: There were 43 in-hospital deaths, with a mortality of 2.30% (43/1887). The logistic regression analysis showed that preoperative myocardial injury classification was a significant risk factor for in-hospital mortality in both total cohort (OR 1.491, 95%CI 1.049-2.119) and subsets (OR 1.761, 95%CI 1.102-2.814). The new risk evaluation system has higher calibration and discrimination power than EuroSCORE II, both for overall cohort and subsets. Especially, the new system has obvious advantages in discrimination power in the subset of acute myocardial infarction (AUC 0.813 vs. 0.772, 0.906 vs. 0.841, and 0.715 vs. 0.646, respectively). CONCLUSIONS: Both myocardial injury classification and EuroSCORE II are independent risk factors of in-hospital mortality in OPCABG patients. The new risk evaluation system has higher predictive ability than EuroSCORE II, especially in patients with a recent history of AMI.

Postoperative acute kidney injury increases short- and long-term death risks in elderly patients (≥ 75 years old) undergoing coronary artery bypass graft surgery.

PURPOSE: To explore the incidence of postoperative acute kidney injury (AKI) after coronary artery bypass grafting (CABG) in elderly Chinese patients (≥ 75 years old) and its impacts on the short- and long-term prognosis. METHODS: A total of 493 patients aged 75-88 years old who underwent CABG from two medical centers between January 2006 and October 2021 were involved. Perioperative (preoperative and 7 days after operation) serum creatinine (Scr) levels were measured in all the enrolled patients. Univariate and multivariate logistic regression analyses were conducted to explore the independent risk factors of postoperative in-hospital mortality. Kaplan-Meier curves and COX model were used to test the risk factors of all-cause death during follow-up. Propensity score matching was used to balance differences between AKI and control groups. The primary outcome event was in-hospital death, and the secondary outcome was all-cause death during follow-up. RESULTS: The 198 patients were diagnosed with postoperative AKI. Intra-aortic balloon pump (IABP), cardiopulmonary bypass, and postoperative AKI were independent risk factors of in-hospital death. Gender, New York Heart Association Classification, preoperative eGFR, last eGFR within 7 days after operation, postoperative AKI, and postoperative renal function all impacted long-term prognosis. After 1:1 matching, 190 patients were included in the AKI and control groups. Use of IABP, use of cardiopulmonary bypass, and occurrence of postoperative AKI were still independent risk factors of in-hospital death. Preoperative eGFR, last eGFR within 7 days after operation, postoperative AKI and postoperative renal function all impacted long-term prognosis. CONCLUSION: The incidence of postoperative AKI in elderly patients undergoing CABG is high, and postoperative AKI is an independent risk factor of both short- and long-term postoperative prognosis.

The clinical applications of ensemble machine learning based on the Bagging strategy for in-hospital mortality of coronary artery bypass grafting surgery.

Background: Machine learning (ML) has excelled after being introduced into the medical field. Ensemble ML models were able to integrate the advantages of several different ML models. This study compares the ensemble ML model's and EuroSCORE II's performance predicting in-hospital mortality in patients undergoing coronary artery bypass grafting surgery. Methods: The study included 4,764 patients from three heart centers between January 2007 and December 2021. Of these, 3812 patients were assigned to the modeling group, and 952 patients were assigned to the internal test group. Patients from other two heart center (1733 and 415 cases, respectively) constituted the external test group. The modeling set data are trained using each of the three ML strategies (XGBoost, CatBoost, and LightGBM), and the new model (XCL model) is constructed by integrating these three models through an ensemble ML strategy. Performance of different models in the three test groups comparative assessments were performed by calibration, discriminant, decision curve analysis, net reclassification index (NRI), integrated discriminant improvement (IDI), and Bland-Altman analysis. Results: In terms of discrimination, the XCL model performed the best with an impressive AUC value of 0.9145 in the internal validation group. The XCL model continued to perform best in both external test groups. The NRI and IDI suggested that the ML model showed positive improvements in all three test groups compared to EuroSCORE II. Conclusions: ML models, particularly the XCL model, outperformed EuroSCORE II in predicting in-hospital mortality for CABG patients, with better discrimination, calibration, and clinical utility.

Advances of Liquid Biopsy for Diagnosis of Atrial Fibrillation and Its Recurrence After Ablation in Clinical Application.

Atrial fibrillation (AF) is a common arrhythmia disease with high morbidity in clinical practice and leads to stroke, heart failure, peripheral embolism, and other severe complications. With aging of the society, AF has become one of the biggest public health challenges. Effective treatments including antiarrhythmic drugs, electrical cardioversion, and ablation (with or without catheters) can alleviate the symptoms of AF. Ablation is the most effective method for the treatment of persistent AF, but cannot cure all patients. Recurrence of AF is a realistic and unavoidable problem. For early predicting and warning of AF and its recurrence, liquid biopsy for accurate molecular analysis of biofluids is a new strategy with potential value and easy sampling and can detect genetic and epigenetic polymorphisms, especially microRNAs. In this review, liquid biopsy is constructed as a new powerful way for diagnosing AF and predicting its recurrence, contributing to the treatment of AF.

Preoperative prognostic nutritional index is an independent indicator for perioperative prognosis in coronary artery bypass grafting patients.

OBJECTIVES: The prognostic nutritional index is widely used for surgery prognosis, but the association between preoperative prognostic nutritional index and short-term prognosis for coronary artery bypass grafting surgery and the profiles of perioperative prognostic nutritional index remain unclear. METHODS: This study retrospectively enrolled a total of 879 adult patients undergoing coronary artery bypass grafting surgery in the Shanghai Chest Hospital from 2006 to 2022. The prognostic nutritional index was calculated based on serum albumin and peripheral lymphocyte count. In-hospital mortality, demographic characteristics, blood biochemistry parameters, cardiovascular medical history, and physical examination results were collected from the hospital information system. The propensity score matching method and multivariate logistic regression were used to detect the association between preoperative prognostic nutritional index and in-hospital mortality. RESULTS: Patients were divided into a high-prognostic nutritional index group (n = 500) and a low-prognostic nutritional index group (n = 379), using a cutoff value of 48.1 according to receiver operating characteristic curve analysis. The propensity score matching-adjusted mean prognostic nutritional index levels decreased from 48.35 before the operation to 34.04 an in ≤24 h after the operation and rebounded to 43.36 before discharge. High preoperative prognostic nutritional index was inversely associated with in-hospital mortality for coronary artery bypass grafting surgery (odds ratio = 0.86; 95% CI, 0.77-0.97) in propensity score matching-adjusted multivariate logistic regression. CONCLUSIONS: Preoperative prognostic nutritional index is an independent indicator for in-hospital mortality of for coronary artery bypass grafting surgery, and the variation trend of prognostic nutritional index during perioperation tends to be U-shaped.

Release Profile of Cardiac Troponin T and Risk Factors of Postoperative Myocardial Injury in Patients Undergoing CABG.

BACKGROUND: Cardiac troponin T (cTnT) is currently one of the important indicators for clinical diagnosis of myocardial injury, which is inevitable in cardiac surgery, especially coronary artery bypass grafting (CABG). Describing the release profile of cTnT and finding out the risk factors of postoperative myocardial injury (PMI) are of great significance. The purposes of this study are to explore the release profile of cTnT in patients undergoing CABG and to search for independent risk factors of PMI. METHODS: In this retrospective study, clinical data of CABG patients were collected. The cTnT was measured at 24 hours before and 6, 12, 24, 48, 72, 96 and 120 hours after operation separately. The release profiles and peak time of cTnT in total cohort and sub-cohorts were observed. Independent risk factors of PMI were explored via univariate and multivariate logistic regression analyses. RESULTS: In total, 2084 patients were enrolled, including 998 patients in a cTnT group and 1086 patients in a high-sensitive cTnT (hs-cTnT) group. PMI was recognized in 797 patients. In both groups, cTnT showed a trend of rising first and then falling within 120 hours after operation. The peak cTnT appeared within 12-24 hours after operation, while the peak hs-cTnT occurred mostly within 24-48 hours after operation. Univariate logistic analysis showed that body mass index (BMI), New York Heart Association (NYHA) classification, coronary artery disease (CAD) classification, cerebrovascular disease, left ventricular ejection fraction, number of diseased vessels, valvular disease, intra-aortic balloon pump (IABP) implantation, chronic obstructive pulmonary disease, pulmonary hypertension, previous percutaneous coronary intervention (PCI), BMI, bypass graft number, cardiopulmonary bypass, and preoperative cTnT were related risk factors. Multivariate logistic regression analysis showed that NYHA classification, CAD classification, valvular disease, IABP implantation, pulmonary hypertension, previous PCI, bypass graft number, cardiopulmonary bypass, and preoperative cTnT were independent risk factors of PMI. CONCLUSION: NYHA classification, CAD classification, valvular disease, IABP implantation, pulmonary hypertension, previous PCI, bypass graft number, cardiopulmonary bypass, and preoperative cTnT are independent risk factors of PMI in patients undergoing CABG.

Predictive Ability of European Heart Surgery Risk Assessment System II (EuroSCORE II) and the Society of Thoracic Surgeons (STS) Score for in-Hospital and Medium-Term Mortality of Patients Undergoing Coronary Artery Bypass Grafting.

OBJECTIVE: To evaluate the powers of European Heart Surgery Risk Assessment System II (EuroSCORE II) and the Society of Thoracic Surgeons (STS) score in predicting in-hospital and medium-term mortality of patients undergoing coronary artery bypass grafting (CABG). METHODS: Totally 1628 Chinese patients were included between January 2000 and January 2018. Their perioperative clinical data were collected and the patients were closely followed up. According to the length of follow-up time, the total cohort was divided into 1-year, 2-year, 3-year, 4-year and 5-year groups. The in-hospital and medium-term risk prediction of EuroSCORE II and STS score were comparatively assessed by calibration, discrimination, decision curve analysis (DCA), net reclassification index (NRI), integrated discrimination improvement (IDI) and Bland-Altman analysis. RESULTS: About 36 (2.21%) patients died during hospitalization. Both EuroSCORE II and STS score performed extremely well in predicting in-hospital mortality (area under curve = 0.900 and 0.879, respectively). However, calibration and discrimination analyses showed gradual decrease when these two risk evaluation systems were used to predict mortality during the follow-up period. At the same time, the predictive ability of EuroSCORE II was better than STS score. DCA curves showed that the performances of the two evaluation systems were roughly equal between the threshold probability of 0% to 20%. The percentage of correct reclassification of EuroSCORE II was 21.64% higher than that of STS score in predicting 2-year postoperative mortality. The IDI index showed that the predictive capabilities of these two systems were roughly equivalent. Bland-Altman analysis showed no significant difference between the values of the two systems. CONCLUSION: EuroSCORE II and STS score have excellent predictive powers in predicting in-hospital mortality of patients undergoing CABG. In particular, EuroSCORE II is superior in calibration and discrimination. The prediction efficiency of the two risk evaluation systems is still acceptable for two-year postoperative mortality, but decreases year by year.

Assessment of three risk evaluation systems for patients aged ≥70 in East China: performance of SinoSCORE, EuroSCORE II and the STS risk evaluation system.

OBJECTIVES: To assess and compare the predictive ability of three risk evaluation systems (SinoSCORE, EuroSCORE II and the STS risk evaluation system) in patients aged ≥70, and who underwent coronary artery bypass grafting (CABG) in East China. METHODS: Three risk evaluation systems were applied to 1,946 consecutive patients who underwent isolated CABG from January 2004 to September 2016 in two hospitals. Patients were divided into two subsets according to their age: elderly group (age ≥70) with a younger group (age <70) used for comparison. The outcome of interest in this study was in-hospital mortality. The entire cohort and subsets of patients were analyzed. The calibration and discrimination in total and in subsets were assessed by the Hosmer-Lemeshow and the C statistics respectively. RESULTS: Institutional overall mortality was 2.52%. The expected mortality rates of SinoSCORE, EuroSCORE II and the STS risk evaluation system were 0.78(0.64)%, 1.43(1.14)% and 0.78(0.77)%, respectively. SinoSCORE achieved the best discrimination (the area under the receiver operating characteristic curve (AUC) = 0.829), followed by the STS risk evaluation system (AUC = 0.790) and EuroSCORE II (AUC = 0.769) in the entire cohort. In the elderly group, the observed mortality rate was 4.82% while it was 1.38% in the younger group. SinoSCORE (AUC = .829) also achieved the best discrimination in the elderly group, followed by the STS risk evaluation system (AUC = .730) and EuroSCORE II (AUC = 0.640) while all three risk evaluation systems all had good performances in the younger group. SinoSCORE, EuroSCORE II and the STS risk evaluation system all achieved positive calibrations in the entire cohort and subsets. CONCLUSION: The performance of the three risk evaluation systems was not ideal in the entire cohort. In the elderly group, SinoSCORE appeared to achieve better predictive efficiency than EuroSCORE II and the STS risk evaluation system.

Feasibility and efficacy of simultaneous off-pump coronary artery bypass grafting and esophagectomy in elderly patients.

INTRODUCTION: To analyze the outcomes of off-pump coronary artery bypass grafting (OPCABG) and esophagectomy simultaneously for patients with coronary artery disease (CAD) and coexisting esophageal cancer. METHODS: Twenty-two patients with CAD and coexisting esophageal cancer underwent combined surgical interventions were subjected to the study. OPCABG was performed first, followed by esophagectomy. All the corresponding data including clinicopathological characteristics and postoperative outcomes were all investigated. RESULTS: All the combined procedures were performed successfully. The average number of grafts was 2.36. Tumors were located at the middle third of the esophagus in 5 patients, at the lower third of the esophagus in 8 patients, at the esophageal gastric junction (EGJ) in 9 patients, respectively. The operations were carried out through a left lateral thoracotomy approach in 21 patients while a median sternotomy and left lateral thoracotomy approach was used in 1 patient for his condition rapidly worsened. Postoperatively, pneumonia occurred in 4 patients (18.2%). During the follow-up, three patients died of cancer metastasis /recurrence (6, 18, 37 months) and one died of pneumonia (1 month). The cumulative 5 years survival rate is 52.9%. CONCLUSIONS: The combined procedure of OPCABG and esophagectomy is a safe and effective treatment option for patients with severe CAD and esophageal cancer.

Validation of SinoSCORE for isolated CABG operation in East China.

From January 2010 to December 2016, 1616 consecutive patients who underwent isolated coronary artery bypass grafting (CABG) were evaluated for their predicted mortality according to the online Sino System for Coronary Operative Risk Evaluation (SinoSCORE), European System for Cardiac Operative Risk Evaluation II (EuroSCORE II) and Society of Thoracic Surgeons (STS) risk evaluation system. The calibration and discrimination in the total and in the subsets were assessed by the Hosmer-Lemeshow (H-L) statistics and by the C statistics respectively, to evaluate the efficiency of the three risk evaluation systems. The realized mortality was 1.92% (31/1616). The predictive mortality of SinoSCORE, EuroSCORE II and STS risk evaluation system were 1.35%, 1.74% and 1.05%, respectively. SinoSCORE achieved best discrimination. When grouping by risk, SinoSCORE also achieved the best discrimination in high-risk group, followed by STS risk evaluation system and EuroSCORE II while SinoSCORE and EuroSCORE II had excellent performance in low-risk group. In terms of calibration, SinoSCORE, EuroSCORE II and STS risk evaluation system all achieved positive calibrations (H-L: P > 0.05) in the overall population and grouped subsets. SinoSCORE achieved good predictive efficiency in East China patients undergoing isolated CABG and showed no compromise when compared with EuroSCORE II and STS risk evaluation system.