Two dimensional global longitudinal strain of right ventricle using transthoracic echocardiography can detect right ventricular fibrosis confirmed by 320 slice CT in pulmonary hypertension

Purpose: To detect right ventricular (RV) fibrosis confirmed by 320 slice CT in subjects with pulmonary hypertension (PH) we employed two dimensional (2D) global longitudinal strain (GLS) of RV using transthoracic echocardiography (TTE). Methods: A total of 24 PH subjects confirmed by right heart catheterization (RHC) within the previous 6 months (8 male, age 57±14 years, 15 chronic thromboembolic PH and 9 pulmonary arterial hypertension) underwent TTE (IE33) and 320 slice CT (Aquilion one). On CT, RV fibrosis was defined as an early defect in the early phase and conversely abnormal enhancement in the late phase. Results: RV fibrosis was detected in 8 subjects (33%) on CT. On TTE, the percentage of subjects with RV wall thickness ≥5mm in end-diastole was significantly higher and tricuspid annular plane systolic excursion was significantly smaller in subjects with RV fibrosis than in those without (71.4% vs 25.0%, and 11.6±2.3mm vs 19.7±4.0mm, both P<0.01). Absolute values of 2D GLS for whole RV and RV free wall alone excluding the inter-ventricular septum were significantly smaller in subjects with RV fibrosis than in those without (both P=0.002). There were no significant differences in RHC findings between groups. Receiver operating characteristic curves of 2D GLS for whole RV and RV free wall alone on TTE showed area under curve of 0.898 (whole RV) and 0.898 (RV free wall alone), and best cutoff points of -10.8% (sensitivity 100.0%, specificity 68.7% for whole RV) and -10.6% (sensitivity 87.5%, specificity 81.2% for RV free wall alone), to distinguish subjects with and without RV fibrosis on CT. Conclusions: PH subjects with RV fibrosis on CT can be differentiated from those without, not by RHC findings, but by 2D GLS of both whole RV and RV free wall alone, using TTE.