Echocardiographic study of right ventricular dysfunction in patients with chronic thromboembolic pulmonary hypertension: Comparison of the right ventricular free wall longitudinal strain and conventional parameters

Objective To compare the value of right ventricular (RV) free wall longitudinal strain (FWLS) by speckle tracking echocardiography (STE) and conventional parameters in evaluation of RV dysfunction in chronic thromboembolic pulmonary hypertension (CTEPH). Methods Sixty CTEPH patients were enrolled as group A and 45 pulmonary embolism (PE) patients with normal pulmonary pressure were enrolled as group B in this study. CTEPH patients were divided into 2 subgroups using the World Health Organization (WHO) function classification: patients with WHO Ⅰ-Ⅱ were designated as group A1 and those with WHO Ⅲ-Ⅳ were designated as group A2. Conventional RV functional parameters including tricuspid annular plane systolic excursion (TAPSE), tissue Doppler-derived tricuspid annular systolic velocity (S′), fractional area change (FAC), RV index of myocardial performance (RVIMP), and STE-derived RV FWLS were measured and compared. Clinical right heart failure (RHF) was defined as the presence of symptoms of heart failure and signs of systemic circulation congestion during hospitalization. Results Compared to group B, group A patients had significant enlarged right heart dimension and impaired RV systolic function parameters (all P<0.001). The TAPSE, S′, FAC, and RV FWLS showed significant differences between CTEPH patients with mild (group A1) and severe symptoms (group A2) (all P<0.01), while RVIMP showed no significant difference (P=0.188). On receiver operating characteristic analysis, FWLS had the largest AUC to identify RHF (AUC=0.864, P<0.001), when the cutoff value was 15.05%, the sensitivity was 85.71%, and the specificity was 64.29%, respectively. On binary logistic regression analysis, only right atria area (OR=1.212, 95%CI=1.004-1.48, P=0.046) and RV FWLS (OR=0.662, 95%CI=0.470-0.933, P=0.018) were identified as independent predictor of RHF. Conclusions Compared with conventional parameters, RV FWLS showed advantages in identifying abnormal RV function in CTEPH patients. Key words: Echocardiography; Pulmonary embolism; Hypertension, pulmonary; Ventricular function, right; Strain