Identification of Cardiac MRI and Bio-Marker Thresholds for One-Year Survival in Pre-Capillary Pulmonary Hypertension: Prospective Study

Abstract

Background and objectives: Non-invasive imaging of the heart has an important place in the diagnosis and management of pulmonary arterial hypertension (PAH). The aim of this study was to establish the thresholds of cardiac magnetic resonance imaging (CMRI)-derived biventricular deformation, function parameters, and levels of N-terminal pro brain natriuretic peptide (NT-proBNP) for the prediction of survival of pre-capillary pulmonary hypertension (PHprecap) patients. Materials and Methods: In total, 64 incident PHprecap cases, who underwent CMRI, were consecutively enrolled in a prospective cohort study. Patients underwent a systemic evaluation, including measurement of NT-proBNP, two-dimensional (2D) echocardiography, six-minute walk test (6MWT), CMRI with feature tracking (FT), and right-heart catheterization (RHC). Patients were divided into two groups according to one-year survival (survival and non-survival groups). Survival analysis was performed. Results: One-year survival was 79.6%. The distribution between age, sex, mean pulmonary artery pressure (mPAP), New York Heart Association (NYHA) functional class, and 6MWT did not differ between the groups. Survival was significantly lower in the PAH group associated with connective tissue disease (CTD-PAH), where 44% (n = 4) of patients died during the first year. Univariate analysis revealed that severely reduced right-ventricle (RV) ejection fraction (EF) <25.5%, left-ventricle global longitudinal strain (LV GLS) >-14.18%, and right pulmonary artery (RPA) relative area change (RAC) <19%, and severely increased NT-proBNP level >1738 (ng/L) indicate an increased risk of death in PH_precap patients. Conclusions: Impaired RV systolic function and LV global longitudinal strain, decrease of pulmonary artery distensibility, and CTD-PAH etiology, together with high NT-proBNP level, impair prognosis in pre-capillary PH patients. These findings are important for the risk stratification and management of pre-capillary pulmonary hypertension patients.

Keywords: cardiac magnetic resonance; feature tracking; pulmonary hypertension; right ventricle.

Figure 1

Steady-state free precession (SSFP) cine imaging by cardiac magnetic resonance imaging of a patient with pulmonary arterial hypertension. SSFP in the four-chamber (a) and short-axis (b) orientation at early diastole showing right heart chamber dilatation and leftward ventricular septal bowing due to increased pressure in the right ventricle (RV). Pericardial effusion is also noticed.

Figure 2

Cross-sectional images of maximal (a) and minimal (b) right pulmonary artery (RPA) area used for determination of relative area change (RAC) according to the following formula: RAC = ((maximum area − minimum area)/minimum area) × 100%. RPA RAC in this case is 17.02%.

Figure 3

Feature tracking (FT) strain curves of two-chamber (a), three-chamber (b), and four-chamber (c) long-axis views. The global longitudinal strain was calculated by averaging all long-axis strain parameters. The example of longitudinal strain measurements in a patient with pulmonary hypertension.