Abstract 10545: Elevated Right Ventricular Oxidative Metabolism in Patients with Chronic Thromboembolic Pulmonary Hypertension (CTEPH) or Pulmonary Arterial Hypertension (PAH) Using C-11 Acetate PET
Background: Increased left ventricular (LV) myocardial oxidative metabolism is associated with poor prognosis in patients with heart failure. However, the same has not been studied for the right ventricle (RV). Chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary arterial hypertension (PAH) have different etiology, but elevated pulmonary arterial pressure may increase RV oxidative metabolism. This possibility has yet to be studied. We sought to evaluate whether there was a difference in RV oxidative metabolism between the two subgroups with pulmonary hypertension (PH) using 11C-acetate positron emission tomography (PET).
Methods: 27 patients with WHO functional class II to III PH including 19 PAH and 8 CTEPH and 8 controls prospectively underwent dynamic 11C-acetate PET. Ventricular function (RV stroke volume) was assessed using magnetic resonance imaging. Mean pulmonary artery pressure (mPAP) was measured using right heart catheterization in PH patients. Dynamic 11C-acetate PET was used to simultaneously measure oxidative metabolism (kmono) for both LV and RV.
Results: The mean PAP (mPAP) was similar between the two PH groups (CTEPH 37.2±10.4 vs PAH 41.4±14.2 mmHg, ns). Both PH patients showed higher RV kmono than did controls (CTEPH 0.048±0.01 min−1, PAH 0.049±0.01 min−1vs 0.030±0.006 min−1, P<0.05) despite similar RV stroke volume among the 3 groups. RV oxidative metabolism was correlated with mPAP (r=0.44, p=0.02), pulmonary vascular resistance (PVR) (R=0.56, P=0.002), and brain natriuretic peptide (BNP) (R=0.42, P=0.03) in all PH patients. There was no significant difference in RV kmono between the two PH groups. In contrast, the LV kmono of the 2 PH groups and the control was similar (CTEPH 0.056±0.008 min−1, PAH 0.055±0.009min−1vs control 0.051±0.007 min−1, ns).
Conclusions: RV oxidative metabolism increased in correlation with increased mPAP, PVR, and the prognosis marker BNP in patients with PH. Despite different etiology, both CTEPH patients and PAH patients had elevated RV oxidative metabolism. RV oxidative metabolism derived using 11C-acetate PET reflects the severity of RV pressure overload both in CTEPH and in PAH. A reduction in RV oxidative metabolism may be a new therapeutic target in patients with CTEPH and PAH.
- Pulmonary hypertension
- Positron emission tomography
- Noninvasive cardiac imaging
- Pulmonary artery
- © 2011 by American Heart Association, Inc.