Background:Pulmonary arterial hypertension (PAH) is a fatal complication of connective tissue diseases (CTDs). Chest CT has been increasingly used in the evaluation of patients with suspected PH noninvasively but there is a paucity of studies.Objectives:Our study was aimed to investigate the cross-sectional area (CSA) of small pulmonary vessels on chest CT for the diagnosis and prognosis of CTD-PAH.Methods:This retrospective study analyzed the data of thirty-four patients with CTD-PAH who were diagnosed by right heart catheterization (RHC) and underwent chest CT between March 2011 and October 2019. We measured the percentage of total CSA of vessels<5 mm2and 5-10 mm2as a percentage of total lung area (%CSA<5and %CSA5-10) on Chest CT. Furthermore, the association of %CSA with mean pulmonary artery pressure (mPAP) was also investigated. Besides, these patients were followed up until October 2019, and Kaplan-Meier survival curves were generated for the evaluation of prognosis.Results:Patients with CTD-PAH had significantly higher %CSA5-10than CTD-nPAH (p=0.001), %CSA5-10in CTD-S-PAH and IPAH was significantly higher than CTD-LM-PAH and COPD-PH (p<0.01). There was a positive correlation between %CSA5-10and mPAP in CTD-PAH (r=0.447, p=0.008). Considering %CSA5-10above 0.38 as a threshold level, the sensitivity and specificity were found to be 0.824 and 0.706, respectively. Patients with %CSA5-10≥0.38 had a lower survival rate than those with %CSA5-10<0.38 (p=0.049).Conclusion:Quantitative parameter, %CSA5-10on Chest CT might serve a crucial differential diagnostic tool for different types of PH. %CSA5-10≥0.38 is a prognostic indicator for evaluation of CTD-PAH.References:[1]Galie N, Humbert M, Vachiery JL, et al. 2015 ESC/ERS Guidelines for the Diagnosis and Treatment of Pulmonary Hypertension. Rev Esp Cardiol (Engl Ed). 2016;69(2):177.[2]Siddiqui I, Rajagopal S, Brucker A, et al. Clinical and Echocardiographic Predictors of Outcomes in Patients With Pulmonary Hypertension. Am J Cardiol. 2018;122(5):872-878.[3]Coste F, Dournes G, Dromer C, et al. CT evaluation of small pulmonary vessels area in patients with COPD with severe pulmonary hypertension. Thorax. 2016;71(9):830-837.[4]Freed BH, Collins JD, Francois CJ, et al. MR and CT Imaging for the Evaluation of Pulmonary Hypertension. JACC Cardiovasc Imaging. 2016;9(6):715-732.[5]Pietra GG, Capron F, Stewart S, et al. Pathologic assessment of vasculopathies in pulmonary hypertension. J Am Coll Cardiol. 2004;43(12 Suppl S):25S-32S.[6]Zanatta E, Polito P, Famoso G, et al. Pulmonary arterial hypertension in connective tissue disorders: Pathophysiology and treatment. Exp Biol Med (Maywood). 2019;244(2):120-131.[7]Rabinovitch M, Guignabert C, Humbert M, Nicolls MR. Inflammation and immunity in the pathogenesis of pulmonary arterial hypertension. Circ Res. 2014;115(1):165-175.[8]Thenappan T, Ormiston ML, Ryan JJ, Archer SL. Pulmonary arterial hypertension: pathogenesis and clinical management. BMJ. 2018;360:j5492.[9]Thompson AAR, Lawrie A. Targeting Vascular Remodeling to Treat Pulmonary Arterial Hypertension. Trends Mol Med. 2017;23(1):31-45.[10]Shimoda LA, Laurie SS. Vascular remodeling in pulmonary hypertension. J Mol Med (Berl). 2013;91(3):297-309.[11]Rabinovitch M. Molecular pathogenesis of pulmonary arterial hypertension. J Clin Invest. 2012;122(12):4306-4313.[12]Seeger W, Adir Y, Barbera JA, et al. Pulmonary hypertension in chronic lung diseases. J Am Coll Cardiol. 2013;62(25 Suppl):D109-116.Acknowledgments:Thanks to all patients involved in this retrospective study. Thanks go to every participant who participated in this study for their enduring efforts in working with participants to complete the study. Thanks to Liangmin Wei for helping us with statistics analysis.Disclosure of Interests:None declared
AB1139 DIAGNOSTICIS AND PROGNOSTICIS SIGNIFICANCE OF CHEST CT EVALUATION OF SMALL PULMONARY VESSELS IN CONNECTIVE TISSUE DISEASES WITH PULMONARY ARTERIAL HYPERTENSION.