The Significance Of Chest CT Measurement Parameters In The Diagnosis Of Pulmonary Arterial Hypertension In Patients With Acute Exacerbation Of Chronic Obstructive Pulmonary Disease

Objective:To investigate the significance of CT-based measurement parameters of pulmonary vessels and lung parenchyma in the diagnosis of acute exacerbation of chronic obstructive pulmonary disease complicated with pulmonary hypertension(AECOPD-PH).Methods:A total of 116 patients with acute exacerbation of chronic obstructive pulmonary disease(AECOPD)who were admitted to the Respiratory and Critical Care Medicine Department of Shanxi Bethune Hospital between September 2020 and December 2022were collected as the subjects of this study.The patients’general information,transthoracic echocardiography(TTE)indicators,and other information were recorded.After admission,chest HRCT was performed and the images were transmitted to automatic analysis software to automatically measure quantitative parameters using different algorithms,including mean lung density(m LD),low attenuation area percentage(LAA%)(LAA%<-950Hu,LAA%<-910Hu).The diameter of the ascending aorta(m Ao),main pulmonary artery(m PA),the ratio of the cross-sectional diameter of the pulmonary artery to the aorta(PA/A),and the cross-sectional area of pulmonary vessels with a diameter less than 5mm~2were measured.The ratio of the pulmonary artery angle(PA angle)to the total lung area(%CSA<5)was also measured.PH was assessed as low,medium,or high likelihood based on TTE results.Patients with low or medium likelihood of PH were included in the AECOPD group(59 cases),and those with high likelihood of PH were included in the AECOPD-PH group(57 cases).The general information,pulmonary vascular parameters,and pulmonary parenchymal parameter levels of the two groups of patients were compared to determine the influencing factors of AECOPD-PH.ROC curves were drawn for the indicators with significant differences between the two groups,and the area under the curve(AUC)was calculated to evaluate their diagnostic value in AECOPD-PH patients.Based on the pulmonary arterial hypertension risk stratification table in the"Diagnosis and Treatment Guidelines for Pulmonary Arterial Hypertension in China(2021 edition)",we divided AECOPD-PH patients into low-risk group(22 cases)and medium-high risk group(35 cases).We compared the general information,pulmonary vascular parameters,and lung parenchymal parameter levels of the two groups of patients,clarified the influencing factors of AECOPD-PH patient risk stratification,and used ROC curve analysis to predict the optimal threshold for significant differences in lung parameters in AECOPD-PH patient risk stratification.Results:1.In the comparison between the pure AECOPD group and the AECOPD-PH group,general data such as gender,age,smoking index,BMI,and so on,showed no statistically significant differences(P>0.05).However,there were significant differences in pulmonary vascular parameters,including%CSA<5,m Ao,m PA,PA/A,and PA angle(P<0.05),with optimal thresholds of 0.006,34.45mm,32.85mm,0.97,and 79.10 degrees,respectively.The corresponding areas under the curve(AUC)were 0.850,0.668,0.751,0.696,and 0.359,and the sensitivities were 0.860,0.807,0.632,0.474,and 0.772,with specificities of 0.864,0.576,0.814,0.881,and 0.203,respectively.As for the lung parenchyma parameters,there were statistically significant differences in m LD,%LAA<-910Hu,and%LAA<-950Hu(P<0.05),with optimal thresholds of-707.96Hu,31.24%,and 7.01%,respectively.The corresponding AUC values were 0.817,0.881,and 0.948,and the sensitivities were 0.791,1.00,and 1.00,with specificities of0.881,0.712,and 0.746.2.In the comparison between the low-risk and intermediate-to-high-risk AECOPD-PH groups,general data such as gender,age,smoking index,and BMI showed no statistically significant differences(P>0.05).However,there were significant differences in pulmonary vascular parameters,including%CSA<5,m Ao,m PA,PA/A,and PA angle(P<0.05),with optimal thresholds of 0.0051,34.85mm,33.00mm,0.9027,and 89.15 degrees,respectively.The corresponding areas under the curve(AUC)were0.857,0.769,0.850,0.713,and 0.693,and the sensitivities were 0.886,0.829,0.829,0.800,and 0.543,with specificities of 0.227,0.591,0.773,0.591,and 0.227,respectively.As for the lung parenchyma parameters,there were statistically significant differences in m LD,%LAA<-910Hu,and%LAA<-950Hu(P<0.05),with optimal thresholds of-857.84Hu,60.92%,and 24.94%,respectively.The corresponding AUC values were0.835,0.666,and 0.731,and the sensitivities were 0.657,0.468,and 0.714,with specificities of 0.909,1.00,and 0.818.Conclusion:1.The m Ao,m PA,PA/A,and%CSA<5 parameters of chest CT have diagnostic value for the diagnosis and risk stratification of AECOPD-PH.2.The m LD,%LAA<-910Hu,and-950Hu parameters of lung parenchyma in chest CT have diagnostic value for the diagnosis and risk stratification of AECOPD-PH.3.The diagnostic value of the%CSA<5 parameter is highest in the diagnosis and risk stratification of AECOPD-PH.