PET/CT Imaging of the Right Heart Perfusion and Glucose Metabolism Depending on a Risk Status in Patients With Idiopathic Pulmonary Arterial Hypertension.

Abstract

Right ventricular heart failure (RV HF) is the leading cause of death in pulmonary arterial hypertension (PAH). Relevance of the low-risk status assessment using available diagnostic tools requires a reliable confirmation. The study aimed to evaluate right ventricular perfusion and glucose metabolism using positron emission tomography (PET)/computed tomography (CT) with [13N]-ammonia and [18F]-fluorodeoxyglucose ([18F]-FDG) in 30 IPAH patients (33.8 ± 9.4 years) according to ESC/ERS 2022 risk status. The ratio of SUVmax_RV/LV metabolism and SUVmax_RV/LV perfusion showed significant positive correlation with pulmonary artery pressure, right heart dilatation, NT-proBNP level and negative correlation with the RV ejection fraction. The SUVmax_RV/LV perfusion and SUVmax_RV/LV metabolism ratios differed significantly according to risk status. Low risk patients had a SUVmax_RV/LV metabolism comparable to the controls without PH. The SUVmax_RV/LV perfusion ratio was elevated in low-risk IPAH patients compared with controls. Increased SUVmax_RV/LV perfusion may be an early marker of coronary flow adaptation to RV pressure overload in low-risk IPAH patients and requires further evaluation. Further long-term studies are needed to determine the clinical relevance and cut-off values for the RV/LV PET/CT with [13N]-ammonia and [18F]-fluorodeoxyglucose ([18F]-FDG) uptake in different IPAH risk groups.