The value of routine pulmonary function in screening and evaluating COPD with pulmonary hypertension

Abstract

Objective To explore the value of routine pulmonary function test (PFT) in screening and evaluating pulmonary hypertension (PH) in patients with chronic obstructive pulmonary disease (COPD). Methods 92 patients with COPD who underwent right cardiac catheterization (RHC) in Shanghai Pulmonary Hospital from December 2008 to March 2018 and underwent PFT within 2 weeks of catheterization were retrospectively analyzed.Baseline data were collected, including demographic characteristics, PFT, echocardiography (Echo), RHC, and so on.Independent-samples t test and χ2 test were used to compare the baseline.Univariate and multivariate logistic regression analysis were used to choose the PFT parameters predicting COPD related PH (COPD-PH). PFT prediction index (PFPI) was constructed for COPD-PH screening.The receiver operating curve (ROC) was used to find the optimal cutoff value of PFPI.The correlation between PFT and the severity of COPD-PH was analyzed by Spearman correlation. Results There were 33 patients COPD without PH (COPD-nonPH) among 92 patients, 59 were COPD-PH, of which, 28 were mild COPD-PH (21 males), 31 severe COPD-PH (21 males). The formula of PFPI was constructed according to the results of multivariate logistic regression analysis.Based on the receiver operating curve (AUC=0.78, 95%CI: 0.67-0.89, P<0.01), the optimal cutoff value of PFPI was 0.53 (sensitivity 68%, specificity 81%). Among COPD-PH, diffusion capacity for carbon monoxide of the lung (DLCO) (r=0.52, P<0.01), DLCO percentage of predicted value (r=0.68, P<0.01)were positively correlated with cardiac index. Conclusions PFPI has good sensitivity and high specificity, and should be used to screening COPD-PH in COPD patients.There is a significant association between DLCO and CI in COPD-PH, indicating the lower DLCO is, the worse cardiac pump function is. Key words: Respiratory function tests; Pulmonary disease, chronic obstructive; Hypertension, pulmonary; Pulmonary diffusing capacity; Right cardiac catheterization