Objective To investigate the influencing factors of low cardiac output syndrome(LCOS)after coronary artery bypass grafting(CABG)and construct a nomogram model to predict the risk of LCOS occurrence.Methods A total of 231 patients with coronary atherosclerotic heart disease who underwent CABG surgery in the Heart Center of Henan Provincial People's Hospital from October 2019 to May 2022 were selected for the study.The patients were randomly divided into a training set(n=162)and a validation set(n=69)at a ratio of 7∶3.The comparability between the parameters of the patients in the training and validation sets was assessed.Based on the occurrence of LCOS after CABG,patients in the training set were divided into LCOS group(n=33)and non-LCOS group(n=129).Univariate and multivariate logistic regression analysis were conducted on the sample parameters in the training set to identify independent risk factors for LCOS after CABG.A nomogram prediction model for the risk of LCOS after CABG was constructed,and its discrimination,calibration,and clinical applicability were evaluated by using the receiver operating characteristic curve,calibration curve,and decision curve analysis.Results The incidence of LCOS in patients of the training and validation sets was 20.37%(33/162)and 18.84%(13/69),respectively.There were no statistically significant differences in various parameters between the training and validation sets(P>0.05).In the training set,there were statistically significant differences in the following parameters between the non-LCOS group and the LCOS group patients,including age,heart rate,blood urea nitrogen,serum creatinine,estimated glomerular filtration rate(eGFR),serum N-terminal pro B-type natriuretic peptide(NT-proBNP),serum troponin T,left ventricular ejection fraction(LVEF),mitral regurgitation area,history of myocardial infarction,proportion of NYHA class Ⅲ-Ⅳ,proportion of patients requiring cardiopulmonary bypass,surgical duration,intraoperative bleeding volume,and postoperative hemodynamic indicators such as central venous pressure,pulmonary arterial diastolic pressure and pulmonary artery pulse index(PAPI)(P<0.05).Multivariate logistic regression analysis showed that preoperative LVEF decrease[odds ratio(OR)=0.891,95%confidence interval(CI):0.832-0.954,P=0.001)],preoperative eGFR decrease(OR=0.963,95%CI:0.934-0.994,P=0.018),preoperative NT-proBNP increase(OR=1.001,95%CI:1.000-1.001,P=0.006),increased operation time(OR=1.013,95%CI:1.003-1.022,P=0.008),and postoperative PAPI reduction(OR=0.094,95%CI:0.028-0.319,P=0.000)were independent risk factors for LCOS after CABG.A nomogram prediction model was built based on these indicators.In the training set,the nomogram prediction model had an area under the curve(AUC)of 0.931(95%CI:0.890-0.972)for predicting the LCOS occurrence,with a sensitivity of 82.20%and a specificity of 90.90%.In the validation set,the AUC for predicting the LCOS occurrence was 0.907(95%CI:0.813-1.000),with a sensitivity of 96.40%and a specificity of 84.60%.This indicated that the model had high discrimination.The calibration curve showed good consistency between the predicted probability and the actual probability of LCOS occurrence in both the training and validation sets(average absolute error:0.038 and 0.026,respectively).The Hosmer-Lemeshow goodness-of-fit test demonstrated that the model's prediction deviation for the LCOS occurrence was not statistically significant compared to the actual occurrence(x2=6.381,6.907,P>0.05),indicating good calibration of the model.Conclusion Decreased LVEF and eGFR and elevated NT-proBNP preoperatively,prolonged surgical duration,and decreased PAPI postoperatively are independent risk factors for LCOS after CABG.The nomogram prediction model established based on these factors has high discrimination,calibration,and clinical applicability,and can effectively predict the occurrence of LCOS after CABG.
coronary artery bypass graftinglow cardiac output syndromenomogram prediction model