Abstract 13869: The Usefulness of Echocardiographic Indices of Right Ventricular Systolic Function in Patients With Interstitial Pneumonia

Abstract

Introductions: It is well known that interstitial pneumonia (IP) may induce pulmonary hypertension, but there have been few studies about right ventricular (RV) function in patients with IP and usefulness of echocardiographic indices in its evaluation. Methods: We retrospectively investigated 200 consecutive patients with IP. Patients with left heart failure or emphysema were excluded. Conventional left ventricular (LV) parameters and indices of RV function, such as tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC), and longitudinal strain of right ventricular free wall (RVLS) were evaluated. As a substitute for pulmonary vascular resistance, pressure gradient calculated by peak velocity of tricuspid regurgitation (TRPG) / cardiac output (CO) was used. Stage of IP was classified as mild, moderate, and severe, based on the degree of fibrosis and involvement area with CT images. Results: The mean age was 70.5±8.7 years (122 males (61%)). Stage of IP was graded as mild in 96 patients (48%), moderate in 71 patients (35.5%), and severe in 33 patients (16.5%). All LV parameters were normal at all stages of IP. FAC, which is an index of transverse RV systolic function, has not decreased until IP became severe (42.4±7.9 at mild vs. 40.7±7.5 at moderate vs. 32.7±7.1% at severe stage). On the other hand, TAPSE and RVLS, which are indices of longitudinal RV systolic function, showed graded reduction as stage of IP progressed (TAPSE: 21.1±3.0 vs. 18.0±3.3 vs. 15.2±3.2 mm; p<0.01, RVLS: -20.2±4.2 vs. -18.3±5.0 vs. -15.1±3.9%; p<0.01) and these indices have decreased at earlier stage of IP although TRPG and TRPG/CO were not elevated at this stage. (TRPG: 22.5±3.9 vs. 28.2±10.0mmHg, TRPG/CO: 5.0±1.7 vs. 6.1±2.1; mild vs. moderate). In ROC analysis, TAPSE (AUC=0.82) showed high predictive value for distinguishing between mild and moderate /severe IP, and the optimal cut-off values were 18.4mm (sensitivity: 80.0%, specificity: 70.2%). Conclusion: RV dysfunction progressed as stage of IP progressed. TAPSE and RVLS as the indices of longitudinal RV systolic function are useful to detect the earlier stage of RV dysfunction in patients with IP.