Prognostic Value of Energy Loss Index in Asymptomatic Aortic Stenosis

BACKGROUND: Aortic valve area index adjusted for pressure recovery (energy loss index ELI) has been suggested as a more accurate measure of aortic stenosis (AS) severity, but its prognostic value has not been determined in a prospective study. METHODS AND RESULTS: The relation between baseline ELI and rate of aortic valve events and combined total mortality and hospitalization for heart failure resulting from the progression of AS was assessed by multivariate Cox regression and reclassification analysis in 1563 patients with initial asymptomatic AS in the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study. During 4.3 years follow-up, a total of 498 aortic valve events and 181 combined total mortalities and hospitalizations for heart failure caused by the progression of AS occurred. In Cox regression analyses, 1-cm(2)/m(2) lower baseline ELI predicted a 2-fold higher risk both for aortic valve events and for combined total mortality and hospitalization for heart failure independently of baseline peak aortic jet velocity or mean aortic gradient and independently of aortic root size (all P<0.05). In reclassification analysis, ELI improved the prediction of aortic valve events by 13% (95% confidence interval, 5-19), whereas the prediction of combined total mortality and hospitalization for heart failure resulting from the progression of AS did not improve significantly. CONCLUSIONS: In asymptomatic AS patients without known atherosclerotic disease or diabetes mellitus, ELI provides independent and additional prognostic information to that derived from conventional measures of AS severity, suggesting that ELI should be measured in such patients. CLINICAL TRIAL REGISTRATION INFORMATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00092677.