Prognostic Value of Energy Loss Index in Asymptomatic Aortic Stenosis

Abstract

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.

Accurate Assessment of Aortic Stenosis

“…48 This index accounts for pressure recovery in the ascending aorta by including the ascending aortic size in the calculations. Recent work by Bahlmann and colleagues 49,50 from the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study, showed that energy-loss index improved the prediction of AV events by 13%, suggesting that this may be a promising parameter to be used clinically.…”

“…V článku, který nedávno publikovali Bahlmann a spol. 49,50 s údaji ze studie SEAS (Simvastatin and Ezetimibe in Aortic Stenosis), se uvádí, že index ztráty energie zpřesnil predikci příhod AV o 13 %, což naznačuje, že by se mohlo jednat o slibný parametr pro použití v klinické praxi.…”

Energy Loss Index in Aortic Stenosis

“…3 In the large multicenter prospective study published in this issue of Circulation, 4 Bahlmann and colleagues show that a decrease of 1 cm 2 /m 2 in ELI predicts a 6.06-fold increase in AVR, a 5.25-fold increase in aortic valve events, a 1.93-fold increase in total mortality, and a 2.28 increase in combined mortality and hospitalization for heart failure. The hazard ratios for AVR and aortic valve events were March 12, 2013 attenuated (≈2.0) but remained significant after adjustment for peak jet velocity or mean gradient, whereas those for mortality and hospitalization were unchanged.…”

“…3 **Cut point of ELI used for reclassification of stenosis severity in the previous study by Bahlmann et al 7 ***Best cut point of ELI to predict outcomes over a 4-year follow-up in the present study. 4 The black dashed line is the identity line.…”

“…In an article published in 2000 in Circulation, 3 we proposed a new Doppler echocardiographic parameter based on the energy loss concept to adjust the AVA for pressure recovery, and we postulated that this energy loss index (ELI) would improve assessment of stenosis severity and risk stratification in AS. Thirteen years later, Bahlmann and colleagues 4 publish in this issue of Circulation the first prospective study to demonstrate that ELI provides independent and incremental prognostic information to that derived from conventional measures of AS severity. In this elegant substudy of the SEAS (Simvastatin Ezetimibe in Aortic Stenosis) trial, the authors report that a 1 cm²/m² reduction in baseline ELI predicts a 2-fold increase in the risk of aortic valve events and of the composite of mortality and heart failure hospitalization after adjustment for peak aortic jet velocity or mean gradient.…”