Correlation Between Ultrasound Pulmonary Artery Systolic Pressure And Highresolution CT Pulmonary Artery Width In Patients With Chronic Obstructive Pulmonary Disease

Objective:Computed tomography（CT）quantitative measurement technology is increasingly popular in chronic obstructive pulmonary disease（COPD）and other pulmonary diseases.The purpose of this study was to explore the correlation between ultrasound pulmonary artery systolic blood pressure（PASP）and high-resolution CT（HRCT）of main pulmonary artery diameter（PAD）in patients with COPD.Methods:A retrospective analysis of 473 patients with acute exacerbation of chronic obstructive pulmonary disease who were hospitalized in the First Hospital of Lanzhou University from January 2016 to December 2020.According to the PASP obtained by TTE,it is divided into 4 groups:COPD normal PASP group:PASP≤36mm Hg;COPD mildly elevated PASP group:PASP 37 to 50mm Hg;COPD moderately increased PASP group:PASP 51 to 70mm Hg;COPD PASP severely increased group:PASP>70mm Hg.The PAD and the diameter of the ascending aorta（AAD）at the same level are measured in the mediastinal window of the chest HRCT scan,and calculate the ratio of the main pulmonary artery diameter to the ascending aorta diameter（PAD/AAD）.Using IBM SPSS statistics 25.0 statistical software to analyze the differences in basic data,lung function,blood gas analysis indexes,PAD,PAD/AAD of patients with different pulmonary artery systolic pressure groups in acute exacerbation of COPD.To explore the correlation between PAD,PAD/AAD and PASP and lung function and arterial blood gas.Multivariate Logistic regression analysis was used to analyze the risk factors of PAD/AAD>1,and the receiver operating characteristic（ROC）curve was used to evaluate the sensitivity and specificity of PAD and PAD/AAD in predicting different pulmonary artery systolic pressures in COPD.Results:（1）This study collected 473 basic clinical data of hospitalized patients with acute exacerbation of COPD.There were 182 cases in the COPD group with normal PASP,accounting for 38.5%.There were 164 cases in the COPD group with mildly elevated PASP,accounting for 34.7%.There were 89 cases in the COPD group with moderately elevated PASP,accounting for 18.8%.There were 38 cases in the COPD group with severely elevated PASP,accounting for 8.0%.There was no significant difference in the proportion of gender,age,smoking history,body mass index（BMI）,and hypertension among the groups（All P>0.05）.（2）Among the 473 patients with acute exacerbation of COPD in this study,70patients were with lung function grade I,accounting for 14.8%;182 patients with lung function grade II,accounting for 38.5%;and 139 patients with lung function grade III,accounting for was 29.4%;82 patients with lung function grade IV,accounting for17.3%.There were differences in the proportions of different groups with elevated PASP in patients with gradeⅣpulmonary function.Pulmonary ventilation function indexes FEV1,FEV1/FVC,PEF,MMEF,lung volume indexes IC,and diffusion function indexes DLCO,DLCO/VA of COPD patients with moderately elevated PASP group and severely elevated PASP group were both significantly lower than those of COPD patients with normal PASP group and mildly elevated PASP group,and the difference was statistically significant（all P<0.05）.The VC and TLC of COPD patients with moderately elevated PASP group and severely elevated PASP group were significantly lower than those of COPD normal PASP group,and the difference was statistically significant（all P<0.05）.（3）The Pa O₂and Sa O₂of COPD normal group and mildly elevated PASP group were significantly higher than those of COPD moderately elevated PASP group and severely elevated PASP group,and the difference was statistically significant（all P<0.05）.The Pa CO₂in the COPD normal group and mildly elevated PASP group were significantly lower than those in the COPD PASP moderately elevated PASP group and severely elevated PASP group,and the difference was statistically significant（all P<0.05）.（4）The PAD and PAD/AAD of COPD patients with severely elevated PASP group were significantly higher than those in the other three groups,moderately elevated PASP group were both significantly higher than those normal PASP group and the mildly elevated PASP group（all P<0.05）.In order to exclude the influence of elevated systemic pressure on pulmonary circulation hemodynamics in hypertensive patients,this study excluded the combined hypertensive patients and compared them again,and obtained the same results,so the influence of hypertension on the research results can be excluded.The PAD,PAD/AAD and PASP were all positively correlated,and the correlation coefficients r were 0.445 and 0.393,respectively（all P<0.05）.（5）The correlation results of PAD,PAD/AAD and lung function showed that:PAD,PAD/AAD and lung volume index IC,VC,TLC,RV,diffusion function index DLCO and lung ventilation function index FEV1,FVC,PEF,MMEF all showed different degrees of negative correlation,only RV/TLC had a slight positive correlation with PAD and PAD/AAD（all P<0.05）.FEV1%pred was significantly negatively correlated with PAD and PAD/AAD,but the correlation coefficients were all very small,respectively-0.142 and-0.195（all P<0.05）.（6）The correlation results of pulmonary ventilation function and arterial blood gas analysis indicators showed that:FEV1,FEV1%pred,FVC,FVC%pred,FEV1/FVC were positively correlated with Pa O₂and Sa O₂,and negatively correlated with Pa CO₂（all P<0.05）.（7）In multivariate Logistic regression analysis,after adjusting for confounding factors,decreased FEV1%pred reduction was an independent risk factor for PAD/AAD>1 in patients with COPD,OR（95%CI）:0.968（0956,0.980）（P<0.05）.（8）The ROC curve analysis results of PAD and PAD/AAD at different PASP critical values indicate that the area under the curve of PAD at PASP≥37mm Hg、≥51mm Hg and≥71mm Hg is 0.661（95%CI:0.612-0.710）,0.782（95%CI:0.736-0.829）,0.806（95%CI:0.749-0.863）,the corresponding sensitivity and specificity are:0.546,0.736;0.724,0.743;0.842,0.662,respectively.The area under the curve of PAD/AAD for PASP≥37mm Hg、≥51mm Hg and≥71mm Hg are 0.634（95%CI:0.580-0.682）,0.728（95%CI:0.679-0.779）,0.819（95%CI:0.765-0.872）,andthecorresponding sensitivity and specificity are 0.570,0.637;0.709,0.653;0.895 and 0.625,respectively.Conclusion:1.PAD widening and PAD/AAD increase in patients with COPD are correlated with the increase of ultrasound pulmonary artery pressure,PAD and PAD/AAD under HRCT have certain value in identifying the increase of pulmonary artery pressure caused by COPD.2.PAD and PAD/AAD are negatively correlated with lung function.The worse the lung function,the larger the PAD and PAD/AAD.FEV1%pred reduction is an independent risk factor for PAD/AAD>1 in COPD patients.3.The more severe the hypoxia and carbon dioxide retention,the worse the pulmonary ventilation function,the higher the pulmonary artery pressure,and the greater the PAD and PAD/AAD.