Comparison of the value of FAPI imaging and speckle‑tracking echocardiography in assessment of right ventricular remodeling in pulmonary hypertension.

Abstract

Purposes: This retrospective study was designed to explore the relationship between right ventricular fibroblast activation measured by fibroblast activation protein inhibitor (FAPI) imaging and myocardial deformation measured by Speckle‑tracking Echocardiography (STE) in patients with pulmonary hypertension (PH).

Methods: Clinical data of PH patients were collected [15 chronic thromboembolic pulmonary hypertension (CTEPH), 4 PAH, 1 PH with unclear and/or multifactorial mechanisms]. All of patients underwent FAPI imaging and echocardiography within one month. FAPI activity of right ventricle higher than that in the blood pool was defined as abnormal. The global and segmental maximum standardised uptake values (SUV_max) of the right ventricle were measured and further expressed as target-to-background ratio (TBR) with blood pool activity as background. right ventricular global longitudinal strain (RVGLS) and right ventricular free wall longitudinal strain (RVFWLS) including the basal-, mid-, and apical-segments were measured by STE.

Results: Eighteen patients with PH showed abnormal FAPI uptake in right ventricle. No significant differences were found between CTEPH and other types of PH. TBR of right ventricle had negative correlations with RVGLS (r = -0.597, P = 0.005) and RVFWLS (r = -0.586, P = 0.007) at global level. While, at regional level, significant correlation was only demonstrated between TBR of right ventricle free wall and RVFWLS in apical region (r = -0.530, P = 0.016) and middle region (r = -0.457, P = 0.043). Among the traditional Echocardiography parameters, TBR of right ventricle were positively associated with thickness of right ventricular anterior wall (RVAW) (r_s = 0.475, P = 0.034), and inversely with right ventricular systolic function [RVFAC (r = -0.586, P = 0.007) and TAPSE (r = -0.565, P = 0.009)].

Conclusion: FAPI imaging can partially reflect the right ventricular strain reduction in patients with PH.