Analysis of cardiac energy metabolism in valve disease using P-31-MR-spectroscopy

Purpose: Heart valve disease combined with left ventricular hypertrophy lea ds to derangements in cardiac energy metabolism, which can be detected non- invasively by P-31-MR-spectroscopy. The purpose of the present study was to examine whether the derangements in cardiac metabolism are reversible afte r surgical valve replacement. Patients and methods: 10 healthy volunteers and 10 patients with aortic ste nosis (pressure gradients >60 mmHg) were included. For assessment of energy metabolism,P-31-MR spectra were obtained with a double oblique 3D-CSI tech nique (voxel size 25 cm(3)). In 5 of 10 patients,follow-up examination was performed 3 months after surgical valve replacement (SVR). Left ventricular (LV) function was analyzed by cine MRI. Results: Before SVR the myocardial phosphocreatine to adenosinetriphosphate (PCr-ATP) ratio was significantly (p=0.0002) reduced to 0.80+/-0.25 in pat ients compared to 1.65+/-0.21 in volunteers. 3 months after SVR, LV mass ha d significantly (p=0.04) decreased from 238+/-33 g to 206+/-47 g. At the sa me time a significant (p=0.04) increase of the PCr-ATP ratio from 0.80+/-0. 25 to 1.28+/-0.22 was observed. A slight, but not significant, reduction of the phosphodiester ATP ratio was observed before SVR, with a trend towards normalization after SVR. Conclusions: After SVR, the deranged energy metabolism shows a trend toward s normalization. Further follow-up is necessary to determine whether comple te normalization of the energetic derangement can be observed over longer p eriods of time following SVR.