Effect of Vericiguat on cardiAc Remodeling in Patients With Heart faiLure and Reduced Ejection fractioN (HFrEF): A Prospective sTudy usIng NOvel Echocardiographic Imaging Techniques (VALENTINO)

The biological process that underlies the pathogenesis of heart failure (HF) is termed cardiac remodeling. Pathological cardiac remodeling includes structural and functional change of the heart. Structural cardiac remodeling in HF include dilatation and/or hypertrophy of cardiac chambers, in particular the left ventricle (LV), but can also involve the right ventricle (RV) and both atria; moreover, cardiac valves, in particular the mitral valve, have been shown to undergo adaptive enlargement in HF to counteract leaflet tethering that leads to functional regurgitation 1. Functional changes of the heart in HF includes reduction of LV systolic and diastolic function, ischemia, abnormalities in myocardial deformation, and alteration in intracardiac vortex flow formation and energetics. At the tissue level, cardiac remodeling is marked by interstitial reparative and replacement fibrosis and inflammation. Cyclic guanosine monophosphate (cGMP) is an intracellular second messenger molecule that is important in the pathogenesis of HF. The main kinase effector of cGMP, protein kinase G, counteracts many biological derangements contributing to HF in experimental models. The production of cGMP in the heart, kidney, lung, liver, and brain is triggered by stimulation of either soluble guanylyl cyclase (sGC) or particulate guanylyl cyclase (pGC), and regulated by endogenous receptor ligands such as nitric oxide (NO) and natriuretic peptides (NPs). In the cardiovascular system, cGMP pathway is involved in the pathogenesis of myocardial fibrosis, inflammation, myofilament insensitivity, vascular dysfunction, and cardiomyocyte hypertrophy 2. Vericiguat is a direct sGC stimulator with a dual mode of action: it sensitizes sGC to the body's own NO and increases sGC activity in the absence of NO, causing vasorelaxation, antiproliferation, and antifibrotic effects. A recent randomized trial, Vericiguat Global Study in Subjects with Heart Failure with Reduced Ejection Fraction (VICTORIA), found that vericiguat reduced a composite endpoint of hospitalization for HF and cardiovascular death in high-risk patients with HF with LV ejection fraction (LVEF) less than 45 percent 3. The mechanisms underlying the clinical benefit of vericiguat are uncertain but may include effects on fibrosis and inflammation. Evaluation of LV size by 2D imaging has traditionally be challenging owing to technical limitations, such as foreshortening leading to underestimation of LV volumes using the Simpson's method. Latest advance in 3D echocardiography technology and automated cardiac functional analysis software has revolutionized evaluation and monitoring of LV and LA function in patients with HF. 3D echocardiography allows accurate measurement of LV, LA, and RV volumes and ejection fraction without needing any geometric assumption, with results reproducible and comparable to cardiac magnetic resonance, the imaging gold standard for chamber quantification. Furthermore, speckle tracking echocardiography allows evaluation of cardiac muscle deformation, which are more sensitive and load-independent markers of cardiac function. Echocardiography has the advantage of being wide available, with no harmful effect, and can be repeated in follow-up of patients. Our group is experienced in the evaluation of the cardiac structure and function in patients with HF using 3D, speckle tracking, and other advanced echocardiographic techniques 4-11. The investigators therefore propose to conduct a pilot study to examine the effect of vericiguat on cardiac remodeling in patients with HF and reduced EF (HFrEF) with particular attention paid to the remodeling of LV and LA, using novel imaging techniques including 3-dimensional (3DE), with automated 3D analysis, and speckle tracking echocardiography.