Clinical significance of energy loss index in patients with low-gradient severe aortic stenosis and preserved ejection fraction

Abstract

Aims We hypothesized that among patients with low-gradient severe aortic stenosis (AS) and preserved left ventricular ejection fraction (LVEF), reclassification of AS severity as moderate by pressure recovery adjusted indexed aortic valve area (AVAi) = energy loss index (ELI), may identify a subgroup of patients with a better outcome. Methods and results Three hundred and seventy-nine patients with low-gradient AS (defined by AVAi ≤ 0.6 cm2/m2 and mean aortic pressure gradient < 40 mmHg) and preserved LVEF ≥50% were studied. Reclassification as moderate AS by ELI was defined as AVAi ≤0.6 cm2/m2 but with an ELI >0.6 cm2/m2. Cardiac events [cardiac mortality and/or need for aortic valve replacement (AVR)] during follow-up were studied. One hundred and forty-eight patients (39%) were reclassified as moderate AS by ELI. Reclassification as moderate AS was independently associated with decreased body surface area, normal flow status, decreased left ventricular mass index, and left atrial volume index (all P < 0.05). After adjustment for variables of prognostic interest, reclassification as moderate AS by ELI was associated with a considerable reduction of risk of cardiac events {adjusted hazard ratio (HR) 0.49 [95% confidence interval (CI) 0.33–0.72]; P < 0.001}, need for AVR [adjusted HR 0.52 (95% CI 0.34–0.81); P = 0.004], and cardiac mortality [adjusted HR 0.46 (95% CI 0.22–0.98); P = 0.044]. Conclusion In patients with low-gradient severe AS and preserved LVEF, calculation of ELI permits to reclassify almost 40% of patients as having moderate AS. These reclassified patients have a considerable reduction of the risk of cardiac events during follow-up. Calculation of ELI is useful for decision-making in patients with low-gradient severe AS and preserved ejection fraction.

Pressure Recovery Phenomenon in Aortic Stenosis. An Inconvenient Truth?

“…Altes et al described a 39% reclassification rates from severe to moderate with a two-fold risk reduction of cardiac events during their follow up. 13 Similar findings where described by Heo et al with 45% of the patients initially classified as low-gradient severe AS were reclassified as having moderate AS. 12 Multimodal imaging approaches have also been employed, with one study using multidetector computed tomography and Doppler Echocardiography measurement of the LVOT resulting in the reclassification of 43% of the patients from severe AS to moderate AS using ELCO.…”

Prognosis in asymptomatic patients with discordantly graded aortic valve stenosis based on pressure recovery adjusted valve area

“… 11 Compared with the present study, Altes et al included symptomatic patients, and patients with a number of comorbidities, including history of atrial fibrillation in 40%, chronic renal failure in 32%, and diabetes mellitus in 36% of patients. 11 …”

“…10 Previous studies have demonstrated the prognostic value of pressure recovery adjusted valve area (energy loss (EL)) indexed for body surface area in AS. 9 Use of EL index rather than AVA index reduced the prevalence of asymptomatic severe AS in the large Simvastatin Ezetimibe in Aortic Stenosis (SEAS) study 8 as well as the phenomenon of DGAS in symptomatic patients, as recently demonstrated by Altes et al 11 Recent publications have questioned the value of indexing AVA to body surface area. 12 It is also well demonstrated that both very small and very large body surface area in itself is associated with worse prognosis.…”

Challenges and opportunities in improving left ventricular remodelling and clinical outcome following surgical and trans-catheter aortic valve replacement

“…This apparent discrepancy requires further physiologic and fluid dynamic consideration. Firstly, by calculating the energy loss index of these severe AS patients with normal LVEF based on routine echo assessment, Altes et al [79] reported that up to 40% of cases could be reclassified from severe into moderate AS, thus no longer requiring immediate surgical intervention. Secondarily, the LF-LG AS is frequently associated with systemic hypertension, which is known to have a major impact on the hemodynamic performance of the stenotic aortic valve and left ventricle.…”