Related Experiment Video
Updated: Aug 5, 2026
Comprehensive Echocardiographic Assessment of Right Ventricle Function in a Rat Model of Pulmonary Arterial Hypertension
Published on: January 20, 2023
Effects of riociguat on right ventricular size and function in pulmonary arterial hypertension (RIVER II): a
Satenik Harutyunova1,2, Jonathan Heinz1,2, Nicola Benjamin1,2
1Centre for Pulmonary Hypertension, Thoraxklinik-Heidelberg gGmbH at Heidelberg University Hospital and Translational Lung Research Centre Heidelberg (TLRC), Member of the German Centre for Lung Research (DZL), Roentgenstraße 1, Heidelberg, 69126, Germany.
Background:
Pulmonary arterial hypertension (PAH) is characterized by right ventricular (RV) pressure overload, dilatation and dysfunction, which are key prognostic determinants. While riociguat improves exercise capacity and hemodynamics, prospective data on reverse remodeling remain limited. This prospective, phase IV study evaluated the effects of riociguat on right-heart size, function, hemodynamics, exercise capacity and safety in PAH patients.
Methods:
Treatment-naïve or pretreated PAH patients were enrolled. Patients receiving phosphodiesterase-5 inhibitors (PDE5i) could be switched to riociguat upon clinical indication. The primary endpoint was the change in right atrial (RA) and RV area at 24 weeks. Secondary endpoints included additional echocardiographic, clinical, exercise, hemodynamic and laboratory parameters, as well as quality-of-life (QoL) and safety.
Results:
Thirty patients (61.2 ± 14.5 years; 76.7% male; 24 PDE5i-pretreated) were enrolled. Marked right-heart dilatation and impaired RV function were prominent at baseline. At week 24, riociguat significantly reduced RA (Δ -3.17 ± 5.91 cm²; p = 0.006) and RV area (Δ -6.00 ± 3.80 cm²; p < 0.0001). Furthermore, RV-fractional area change, 6-minute walking distance and functional class improved significantly. In patients with invasive follow-up, cardiac index increased significantly, with favorable trends in further parameters. N-terminal pro-brain natriuretic peptide and QoL remained unchanged. The study terminated early following the decision by the supplier Merck/MSD; the termination was not safety related. Riociguat was generally well tolerated with no new safety concerns.
Conclusion:
Riociguat therapy resulted in a statistically significant improvement in right ventricular and atrial size and function with further improvements in exercise capacity and functional class. This prospective trial confirms the findings of previous retrospective studies and supports riociguat as an effective treatment option to improve RV geometry and performance.
Trial Registration:
This trial was registered on clinicaltrials.gov with the ClinicalTrials.gov ID NCT04954742.
More Related Videos
Related Concept Videos
01:23Treatment for Pulmonary Arterial Hypertension: Prostacyclin Receptor Agonists
These agonists bind to the IPR receptor situated on the plasma membrane of the pulmonary artery smooth muscle cells. This binding triggers a cascade of reactions known as the GS-AC-cAMP-PKA pathway. This pathway results in the relaxation of smooth muscle...
01:26Treatment for Pulmonary Arterial Hypertension: Receptor Tyrosine Kinase Inhibitors and Calcium Channel Blockers
TKIs, such as imatinib (Gleevec), are particularly effective in tackling the growth and mitogenic factors that become upregulated in PAH patients. These factors contribute to the...
01:28Treatment for Pulmonary Arterial Hypertension: Phosphodiesterase Inhibitors
Among the PDE5 inhibitors, sildenafil (Revatio) stands out as a competitive and selective inhibitor. It operates by elevating cellular levels of cGMP and augmenting signaling through the cGMP-PKG pathway, promoting vasodilation. Upon oral...
01:21Cardiac Catheterization II: Right Heart Catheterization
01:18Treatment for Pulmonary Arterial Hypertension: Endothelin Receptor Antagonists
ETs are synthesized through a complex sequence of enzymatic steps, primarily involving an enzyme referred to as endothelin-converting enzyme (ECE). Of...
01:20Mitral Regurgitation I: Introduction