Prognostic interest of energy loss index in patients with low gradient severe aortic stenosis and preserved ejection fraction

Abstract

Assessment of pressure recovery adjusted indexed aortic valve area (AVAi) – energy loss index (ELI) – has been shown of prognostic interest for patients with asymptomatic and/or mild aortic stenosis (AS), but limited data are available in the setting of low gradient aortic stenosis (LG-AS). We hypothesized that among patients with LG-AS and preserved left ventricular ejection fraction (LVEF), reclassification of AS severity as moderate by pressure recovery adjusted indexed aortic valve area (AVAi) may identify a subgroup of patients with a better outcome. A total of 379 patients with LG-AS (defined by AVAi ≤ 0.6 cm 2 /m 2 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 cm 2 /m 2 but with an ELI > 0.6 cm 2 /m 2 . 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 absence of coronary artery disease, decreased body surface area, normal flow status, and decreased left ventricular mass 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 HR 0.50 [95% CI, 0.34–0.73]; P < 0.001), need for AVR (adjusted HR 0.56 [95% CI, 0.36–0.87]; P = 0.008) and cardiac mortality (adjusted HR 0.44 [95% CI, 0.21–0.91]; P = 0.027) ( Fig. 1 ). 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.