Accurate assessment of load-independent right ventricular systolic function in patients with pulmonary hypertension

Background End-systolic elastance (Ees ), a load-independent measure of ventricular function, is of clinical interest for studies of the right ventricle (RV) in patients with pulmonary arterial hypertension (PAH). The objective of this study was to determine whether, in PAH patients, Ees can be estimated from mean pulmonary artery pressure (mPAP) and end-systolic volume (ESV) only. Methods Right heart catheterization was used to measure mPAP. Maximal isovolumic pressure (Piso ) was estimated from RV pressure curves with the so-called single-beat method. Cardiac magnetic resonance imaging (MRI) was used to assess RV end-diastolic and end-systolic volumes (EDV and ESV). Ees was then calculated as: Ees = (Piso −mPAP) / (EDV−ESV), and as Ees,V0 = 0 = mPAP/ESV (simplified method, with V0 = 0, is negligible volume at zero pressure). Right ventricular volume at zero pressure (V0 ) was then defined as the intercept of the end-systolic pressure–volume relation (single-beat method) with the horizontal axis. Results Ees,V0 = 0 was significantly lower compared with Ees (0.61 vs 1.34 mm Hg/ml, respectively, p