C66-06 A Comparative Evaluation of CT and Echocardiographic Parameters as Noninvasive Screening Tools for Group 3 Pulmonary Hypertension in Idiopathic Pulmonary Fibrosis Patients

Abstract Introduction Patients with idiopathic pulmonary fibrosis (IPF) are at increased risk of pulmonary hypertension (PH). Right heart catheterization (RHC) is the gold standard for diagnosis, however, it is invasive. Noninvasive means such as echocardiography have external factors limiting its accuracy. CT derived measurements including pulmonary artery (PA) diameter, PA/aorta ratio (PA/Ao), have shown potential as alternative screening tools. Here, we performed a retrospective study to see if noninvasive echocardiographic parameters—right ventricular systolic pressure (RVSP) and tricuspid annular plane systolic excursion (TAPSE) —and CT-derived parameters—PA diameter, PA/Ao ratio, PA area, and right ventricular (RV) size—can effectively predict PH confirmed by RHC. Methods A retrospective study of 67 IPF patients with group 3 PH undergoing lung transplant evaluation was compared to 63 patients without PH. Each patient required a CT chest, transthoracic echocardiogram, and RHC for inclusion. Patients in the PH group were 18 years old with mPAP 20 and pulmonary capillary wedge pressure 15. All CT chests were read by a single radiologist. Main PA diameter was measured in the transverse axis midway between its root and bifurcation. The ascending aorta diameter was measured at the same level in the anteroposterior axis. RV diameter and PA area were obtained from axial CT studies using the Sectra PACS application. RV diameter was measured at the RV base, and PA area by manual tracing of the main PA lumen. PA diameter, PA/Ao ratio, PA area, RV diameter, RVSP, and TAPSE were compared to mPAP from RHC. Those with 6 months between CT and RHC were excluded. Receiver operator curve (ROC) analysis assessed the efficacy of PA diameter, PA/Ao ratio, PA area, RVSP, TAPSE, and RV diameter compared to RHC parameters. ROC determined cutoff values for each finding. Results A PA diameter 3. 05 cm, PA/Ao ratio 0. 84, RVSP 42. 5 mmHg, TAPSE 16. 4 mm, PA area 745 mm2, and RV diameter 3. 22 cm were all found to be significant predictors of PH by RHC (p 0. 05). ROC analyses with associated area under the curve (AUC), sensitivities, and specificities are reported in Figure 1. Conclusion A PA diameter 3. 05 cm, PA/Ao ratio 0. 84, RVSP 42. 5 mmHg, TAPSE 16. 4 mm, PA area 745 mm², and RV diameter 3. 22 cm are statistically significant predictors (p 0. 05) of PH by RHC. Overall, CT parameters, especially, PA diameter, PA/Ao and PA area were more effective than the echocardiographic parameters in predicting PH in this cohort based on AUC. This abstract is funded by: None