Comparison of CT-Determined Pulmonary Artery Diameter among Smokers and Non-smokers: A Cross-sectional Study

Introduction: Tobacco smoking is a common addiction in our society. The toxic chemical compounds present in tobacco smoke cause epithelial damage and inflammation of the airways. Chronic smoking results in the thickening of the pulmonary arterial wall and vasoconstriction, leading to the development of pulmonary arterial hypertension. Hence, measurement of pulmonary artery diameter using Contrast Enhanced Computed Tomography (CECT) may be helpful in the early detection of pulmonary arterial hypertension. Aim: To compare the diameters of the Main Pulmonary Artery (MPA), Right Pulmonary Artery (RPA), and Left Pulmonary Artery (LPA) using CECT thorax in smokers and non-smokers. Materials and Methods: A cross-sectional study was conducted from April 2021 to March 2022 in the department of radiodiagnosis, KS Hegde Hospital, Karnataka, India, consisting of 100 patients referred for CECT thorax in the age group of 18-85 years. They were divided into two groups: smokers and non-smokers, with 50 patients in each group. They were further categorised into three age groups: < 50 years, 50-60 years, and >60 years. The widest diameters of the MPA were measured at the level of bifurcation of the artery and perpendicular to the long axis of the artery. At this level, RPA and LPA diameters were measured at the widest portion on 1.25 mm axial images of the arterial phase. Variation in the pulmonary artery diameter was compared between smokers and non-smokers with respect to age and analysed by unpaired t-test and Pearson correlation. Results: Diameters of MPA, RPA, and LPA were statistically significant (p<0.05) in smokers compared to non-smokers. In smokers, MPA and RPA diameters correlated with age, which was statistically significant (p<0.05). No significant correlation (p>0.05) was shown between age and MPA, RPA, and LPA diameter in non-smokers. The mean MPA diameter showed a significant difference (p<0.05) in all three age groups. Conclusion: The diameter of the pulmonary artery is statistically significant in smokers compared to non-smokers. Hence, assessment of pulmonary artery diameters among smokers using CECT thorax will help to diagnose Pulmonary Hypertension (PH) at an early stage.