Interventricular septal curvature as an additional echocardiographic parameter for evaluating chronic thromboembolic pulmonary hypertension: a single-center retrospective study

BACKGROUND: Noninvasive estimation of the actual systolic pulmonary artery pressure measured via right-sided heart catheterization (sPAP(RHC)) is vital for the management of pulmonary hypertension, including chronic thromboembolic pulmonary hypertension (CTEPH). Evaluation related to the interventricular septum (IVS) is generally performed with only visual assessment and has been rarely assessed quantitatively in the field of echocardiography. Thus, this study aimed to investigate the utility of echocardiographic IVS curvature to estimate sPAP(RHC) in patients with CTEPH. METHODS: Medical records of 72 patients with CTEPH were studied retrospectively. We estimated sPAP(RHC) using echocardiographic IVS curvature (esPAP(curv)) and left ventricular eccentricity index (esPAP(LVEI)), and compared their ability to predict sPAP(RHC) with estimated sPAP(RHC) using tricuspid regurgitant pressure gradient (esPAP(TRPG)). RESULTS: IVS curvature and LVEI were significantly correlated with sPAP(RHC) (r = − 0.52 and r = 0.49, respectively). Moreover, the IVS curvature was effective in estimating the sPAP(RHC) of patients with trivial tricuspid regurgitation (r = − 0.56) and in determining patients with sPAP(RHC) ≥ 70 mmHg with higher sensitivity (77.0%) compared to those with esPAP(TRPG) and esPAP(LVEI). CONCLUSION: Our results indicate that the echocardiographic IVS curvature could be a useful additional tool for estimating sPAP(RHC) in CTEPH patients for whom accurate estimation of sPAP(RHC) using tricuspid regurgitant pressure gradient is challenging. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12890-021-01683-4.