Abstract 13082: The Impact of Specific Therapy on Glucose Metabolism in Pulmonary Arterial Hypertension Patients - Follow Up Study

Abstract

Introduction: Right ventricular (RV) function is a major determinant of survival in patients with pulmonary arterial hypertension (PAH). In our previous study, we confirmed that increased RV fluorodeoxyglucose (FDG) uptake in positron emission tomography (PET) (presented as higher ratio of FDG uptake of RV to LV) was associated with progressive RV dysfunction and preceded hemodynamic and clinical deterioration in PAH patients. Now, we obtained second PET/MRI assessments of the study group after 2-years of PAH-targeted treatment. Hypothesis: Altered cardiac glucose uptake in severe PAH patients may change after PAH specific treatment. Methods: Twenty-eight PAH patients (51.32±15.91 years) had simultaneous PET/MRI scans performed during baseline visit. Second PET/MRI assessments were done after 2 years in the group of twenty patients (four deaths, four patients did not agree to perform additional scans). Results: After follow-up period, we observed significant change of MRI-derived RV ejection fraction (45±10% to 51.2±12.7%, p=0.03), and improvement in hemodynamic parameters obtained from right heart catheterization e.g. mean pulmonary artery pressure, mPAP (48.5±17.2 to 41.8±17.1 mmHg, p=0.01) and pulmonary vascular resistance, PVR (8.7±5.3 to 7.0±4.2 WU, p=0.04). Follow-up SUVRV/SUVLV ratio was lower than baseline (0.84±0.57 vs 1.02±0.75, p=0.05) and significantly correlated with follow-up RV hemodynamic parameters confirming relationship between RV function and metabolic alterations. Interestingly, patients who had improvement in SUVRV/SUVLV (lower follow-up value than baseline, n=11) had significantly higher mPAP at baseline visit (58.9±18.7 vs 40.3±11.8 mmHg, p=0.02), suggesting that RV FDG accumulation in advanced PAH may decrease after the specific PAH-treatment in accordance with the degree of reduction in the pulmonary vascular resistance. Conclusions: Impaired RV function is associated with increased glucose uptake of RV myocytes estimated by FDG PET in PAH patients. Targeted treatment may improve RV function and thus affect previously altered cardiac glucose uptake.