Impact of energy loss index on left ventricular mass regression after aortic valve replacement

BACKGROUND Recently, the energy loss index (ELI) has been proposed as a new functional index to assess the severity of aortic stenosis (AS). The aim of this study was to investigate the impact of the ELI on left ventricular mass (LVM) regression in patients after aortic valve replacement (AVR) with mechanical valves. METHODS A total of 30 patients with severe AS who underwent AVR with mechanical valves was studied. Echocardiography was performed to measure the LVM before AVR (pre-LVM) (n = 30) and repeated 12 months later (post-LVM) (n = 19). The ELI was calculated as [effective orifice area (EOA) × aortic cross sectional area]/(aortic cross sectional area - EOA) divided by the body surface area. The LVM regression rate (%) was calculated as 100 × (post-LVM - pre-LVM)/(pre-LVM). A cardiac event was defined as a composite of cardiac death and heart failure requiring hospitalization. RESULTS LVM regressed significantly (245.1 ± 84.3 to 173.4 ± 62.6 g, P < 0.01) at 12 months after AVR. The LVM regression rate negatively correlated with the ELI (R = -0.67, P < 0.01). By receiver operating characteristic (ROC) curve analysis, ELI <1.12 cm(2)/m(2) predicted smaller (<-30.0 %) LVM regression rates (area under the curve = 0.825; P = 0.030). Patients with ELI <1.12 cm(2)/m(2) had significantly lower cardiac event-free survival. CONCLUSION The ELI as well as the EOA index (EOAI) could predict LVM regression after AVR with mechanical valves. Whether the ELI is a stronger predictor of clinical events than EOAI is still unclear, and further large-scale study is necessary to elucidate the clinical impact of the ELI in patients with AVR.