Abstract 12565: Right Ventricle 18FDG Uptake in Pulmonary Hypertension: A New Biomarker
Myocardial hypertrophy is associated with an increase in myocardial glucose uptake. This study assessed myocardial glucose uptake in the right ventricle (RV) of patients with pulmonary hypertension and the relationship to haemodynamics and survival. 18F-fluorodeoxy-glucose [FDG] uptake was measured using single photon positron emission tomography (SPECT) in 88 patients with idiopathic pulmonary arterial hypertension (IPAH — n=24), PAH associated with connective tissue disease (n=11) and congenital heart disease (n=43), and chronic thromboembolic pulmonary hypertension (n=10). RV FDG uptake (RV/LV ratio) correlated with pulmonary vascular resistance (PVR) in all categories of pulmonary hypertension (r=0.576, P<0.001). In contrast, there was no correlation between myocardial perfusion, assessed by 99mTc-sestamibi and PVR (r=0.167). A second SPECT scan was performed in 15 IPAH patients after 6 months treatment with sildenafil or a statin. In the responder group (n=6), cardiac index improved from 2.2±0.4 to 3.0±0.7 L/min/m2 (P<0.05) and PVR decreased from 1893±509 to 1087±518 dyn×s×cm−5 (P<0.01) respectively. RV/LV-FDG uptake decreased from 1.38±0.52 before treatment to 0.92±0.26 (P<0.05). In contrast, no significant change in RV/LV-FDG uptake was seen in the non-responder group. Survival in the IPAH group with RV/LV-FDG uptake greater than the median value of 1.15 was significantly lower than that of the group with RV/LV-FDG uptake below 1.15, (log-rank test, P<0.05). FDG uptake by the RV reflects the severity of pulmonary vascular resistance. It is a marker of poor prognosis in idiopathic PAH and is reduced in patients receiving effective therapy. It could prove a useful end point in PAH clinical trials.
- © 2010 by American Heart Association, Inc.