Right ventricular pressure-volume loop shape and systolic pressure change in pulmonary hypertension

Right ventricular (RV) function determines outcome in pulmonary arterial hypertension (PAH). RV pressure-volume loops - the gold standard for measuring RV function - are difficult to analyze. Our aim was to investigate whether simple assessments of RV pressure-volume loop morphology and RV systolic pressure differential reflect PAH severity and RV function. We analyzed multi-beat RV pressure-volume loops (obtained by conductance catheterization with preload reduction) in 77 patients with PAH and 15 patients without pulmonary hypertension in two centers. Patients were categorized according to their pressure-volume loop shape (triangular, quadratic, trapezoid, or notched). RV systolic pressure differential was defined as end-systolic minus beginning-systolic pressure (ESP-BSP); augmentation index as ESP-BSP/pulse pressure; pulmonary arterial capacitance (PAC) as stroke volume/pulse pressure; and RV-arterial coupling as end-systolic/arterial elastance (Ees/Ea). Trapezoid and notched pressure-volume loops were associated with the highest afterload (Ea), augmentation index, pulmonary vascular resistance (PVR), mean pulmonary arterial pressure, stroke work, and B-type natriuretic peptide, and the lowest Ees/Ea and PAC. Multivariate linear regression identified Ea, PVR, and stroke work as the main determinants of ESP-BSP. ESP-BSP also significantly correlated with multi-beat Ees/Ea (Spearman's rho: -0.518, P < 0.001). A separate retrospective analysis of 113 patients with PAH showed that ESP-BSP obtained by routine right heart catheterization significantly correlated with a non-invasive surrogate of RV-arterial coupling (tricuspid annular plane systolic excursion/pulmonary arterial systolic pressure ratio; rho: -0.376, P < 0.001). In conclusion, pressure-volume loop shape and RV systolic pressure differential predominately depend on afterload and PAH severity and reflect RV-arterial coupling in PAH.

• Richter, M. J.
• Hsu, S.
• Yogeswaran, A.
• Husain-Syed, F.
• Vadász, I.
• Ghofrani, H. A.
• Naeije, R.
• Harth, S.
• Grimminger, F.
• Seeger, W.
• Gall, H.
• Tedford, R.
• Tello, K.