Application of FAPI Visualization in the Assessment of Right Ventricular Dysfunction Due to Volume Overload

"Bicuspid aortic stenosis represents the most prevalent form of cardiac valve disease, primarily resulting from degenerative alterations and rheumatic conditions that disrupt mitral valve function. This dysfunction exacerbates the hemodynamic burden on the right heart, leading to secondary pulmonary hypertension-a condition uniquely predisposed to myocardial fibrosis. The role of right ventricular (RV) fibrosis in pulmonary hypertension induced by bicuspid aortic stenosis remains an area of active investigation. Modifications in the extracellular matrix collagen network may mitigate excessive dilation of the pressure-overloaded right ventricle; however, fibrosis concurrently compromises cardiac performance. An increasing body of experimental evidence indicates that fibrosis is pivotal in both the onset and progression of right ventricular dysfunction. In cases of secondary pulmonary hypertension, the right ventricle endures a posterior load approximately five times greater than normal, rendering these circumstances an excellent model for examining pressure loading effects on RV structure. Notably, severe RV fibrosis persists even after hemodynamic normalization following mitral valve repair; thus, preoperative evaluation of RV fibrosis is essential for optimizing patient outcomes in individuals with secondary pulmonary hypertension attributable to bicuspid aortic stenosis.

In recent years, myocardial nuclear imaging has gained prominence as a tool for assessing myocardial fibrosis. Initial studies investigated FAPI myocardial nuclear imaging's efficacy in evaluating left ventricular fibrosis among patients with aortic stenosis; subsequent research elucidated its correlation with sudden cardiac death risk in individuals suffering from obstructive hypertrophic cardiomyopathy.

The comprehension regarding how myocardial fibrosis impacts right ventricular function within patients experiencing pulmonary hypertension due to bicuspid aortic stenosis remains limited. The association between histological RV fibrosis and adverse prognostic indicators as well as outcomes related to right heart failure warrants further exploration."