| Objective: To investigate the predictive value of oxygen uptake kinetics,anaerobic threshold,and multivariate logistic regression analysis of the cardiopulmonary exercise test(CPET)in predicting coronary heart disease.Methods: A total of 237 patients with chest pain from suspected coronary heart disease who underwent CPETs and coronary angiography were selected from the Heart Center of Affiliated Zhongshan Hospital of Dalian University from January 2017 to June 2019.Patients with at least a major coronary artery or a major branch with an inner diameter stenosis of ?50% were included in the coronary heart disease group(104 patients),and patients with an inner diameter stenosis of<50% were included in the non-coronary heart disease group(133 patients).The general information,echocardiographic ejection fraction,CPET and coronary angiography results of the two groups of patients were observed.CPET indicators include heart rate and blood pressure at rest and the following indicators at anaerobic threshold and peak: oxygen uptake(l/min),oxygen uptake per kilogram(ml/kg/min),and oxygen uptake per kilogram of the estimated percentage(%),power(W),heart rate and oxygen pulse(ml/beat),etc.The carbon dioxide(CO2)ventilation equivalent slope(?VE/?VCO2 slope)and the increasing slope of the corresponding power of oxygen uptake(?VO2/?WR(ml/min/W)were also observed.Count data were expressed as composition ratios or percentages.And categorical variables were tested using c2.Independent sample t-tests were used to compare means between groups.Receiver operating characteristic curve(ROC)was used,and area under curve(AUC)was used to evaluate the sensitivity and specificity of CPET indicators in the diagnosis of coronary heart disease.A logistic regression model was used to establish a predictive model of coronary heart disease through CPET indicators.Patients were correctly classified and checked by typical discriminant function analysis.The statistical software SPSS 19.0 was used for data analysis.The difference was statistically significant when P <0.05.Results: The oxygen uptake at anaerobic threshold(VO2,l/min),oxygen uptake per kilogram at anaerobic threshold(VO2/kg,ml/kg/min),oxygen uptake per kilogram of the estimated percentage at anaerobic threshold(VO2% pred,%),heart rate at anaerobic threshold(HR),and oxygen pulse at anaerobic threshold(VO2/HR,ml/beat)of patients in the coronary heart disease group were significantly lower than those of patients in the non-coronary heart disease group.The oxygen uptake at peak(Peak VO2,l/min),oxygen uptake at peak(Peak VO2/kg,ml/kg/min),oxygen uptake per kilogram of the estimated percentage at peak(Peak VO2% pred,%),oxygen pulse at peak(Peak VO2/HR,ml/beat)and the increasing slope of the power corresponding to the oxygen uptake(?VO2/?WR)of patients in the coronary heart disease group were significantly lower than those of patients in the non-coronary heart disease group.The CO2 ventilation equivalent slope(?VE/?VCO2 slope)of patients in coronary heart disease group were significantly higher than those patients in non-coronary heart disease group with statistical differences(P <0.05).With ?VE/?VCO2 slope > 26.29 as a predictor of coronary heart disease,the sensitivity was 68.3% and the specificity was 48.9%.Multivariate regression analysis has showed that VO2/Kg(p <0.05,OR=1.396,95% CI: 1.039 to 1.875)and Peak VO2(p <0.05,OR =1.057,95% CI: 1.016 ~1.099)are independent risk factors for coronary heart disease.And Peak VO2/kg(p<0.05,OR = 0.696,95% CI: 0.546~0.887)and Peak VO2/HR(p<0.05,OR=0.648,95%CI: 0.469~0.896)are protective factors of coronary heart disease.The logistic regression analysis was used to establish the equation model: Logit(Y)= Log [Pr(Y)/ 1-Pr(Y)] = 0.441×1(gender)+ 0.045×2(age)+ 0.333×3(VO2/Kg)+ 0.055×4(Peak VO2)-0.363×5(Peak VO2/kg)-0.434×6(Peak VO2/HR).Pr(Y)in the equation model refers to the probability of suffering from coronary heart disease.The four coefficients of variance expansion coefficients of VO2/Kg,Peak VO2,Peak VO2/kg and Peak VO2/HR are respectively 1.267,5.540,2.257,and 3.910,which are < 10.The typical discriminant function analysis has shown that 90 patients in non-heart disease group were correctly classified and 72 patients in the coronary heart disease group were correctly classified,which the accuracy was 68.4%.Conclusion:1.VO2/Kg and Peak VO2 in CPET indicators are independent risk factors for coronary heart disease.2.?VE/?VCO2 slope in CPET indicators has certain value for the diagnosis of coronary heart disease.3.The multivariate regression equation model based on CPET has predictive value for the diagnosis of coronary heart disease,while it still needs to be further evaluated in a large sample. |
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