Assessment of right ventricular oxidative metabolism by positron emission tomography with C-11 acetate in aortic valve disease.

Evaluation of right ventricular (RV) oxidative metabolism is limited by the inability to easily determine oxygen extraction by the RV myocardium and the complex morphology of this ventricle. Because left ventricular C-11 clearance rate constants closely correlate with myocardial oxygen consumption, it was postulated that C-11 clearance rate constants for the RV free wall should also reflect its oxygen consumption. Therefore, RV C-11 clearance rate constants were compared with RV loading in 21 patients with aortic valve disease to assess the possible use of this technique for noninvasive evaluation of RV oxidative metabolism. RV free wall C-11 clearance rate constants correlated with the product of systolic pulmonary artery pressure and heart rate for all patients (r = 0.65, p = 0.002), but the relation was stronger if 2 patients with overt RV dysfunction were excluded (r = 0.83, p = 0.001). On the basis of mean pulmonary artery pressures, patients were stratified into subgroups with normal (group I, n = 8) and elevated (group II, n = 13) pulmonary pressures and were compared with 10 normal control subjects. RV C-11 clearance rate constants were significantly higher in group II than in group I and in normal control subjects (p less than 0.05). These data suggest that RV C-11 acetate clearance rate constants can provide noninvasive evaluation of RV oxidative metabolism. This technique may allow serial assessment of RV performance in various cardiac and pulmonary diseases, and particularly of changes associated with therapeutic interventions.