Abstract 11627: Association of Cardiac Power Output Index with PET Glucose Metabolism and Prognosis in Pulmonary Arterial Hypertension Patients. Two-year Follow-Up

Introduction: In pulmonary arterial hypertension (PAH) there is still a need for new prognostic markers to precisely identify the patients before clinical deterioration. We investigated cardiac power index (CPi) as a tool to assess right ventricular (RV) function and overall prognosis. Hypothesis: Hemodynamic changes occurring in PAH assessed with CPi are related with cardiac metabolism alterations in PET imaging what affects prognosis. Methods: Twenty-eight stable (WHO class II or III) patients (49.9±15.9 yo) had hybrid PET/MRI scans and heart catheterization performed during baseline and after 24-months. SUV RV/LV ratio was used to estimate cardiac 18-fluorodeoxyglucose uptake. Clinical endpoints (CEP - death or clinical deterioration) were assessed between visits. CPi was defined as the cardiac index х mean pulmonary artery pressure x 2.22 х 10-3. Results: Baseline CPi was 0.28±0.09 W/m2 and it correlated significantly with PET-derived SUV RV/LV ratio (r=0.55, p=0.002), confirming relationship between RV hemodynamics and cardiac metabolism. After 24 months of PAH specific therapy, we observed significant improvement in follow-up CPi - 0.23±0.04 W/m2 (p=0.04). Interestingly, baseline CPi predicted follow-up SUV RV/LV ratio. During 2-year observation, 16 patients (57%) had experienced CEP (including 4 deaths). Patients with CEP had higher baseline CPi than stable patients (0.32±0.09 vs 0.21±0.05, p=0.0006), as well as increased SUV RV/LV. CPi cut-off value to predict worse prognosis was 0.24 W/m2 (log-rank test, p=0.003, Figure) and CPi was also a significant predictor of CEP in multivariate analysis (R2 = 0.69; p=0.001). Conclusions: Indexed cardiac power output parameter is related with RV metabolism alterations in PAH and may help to identify stable patients at higher risk of death or clinical deterioration.