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.