BACKGROUND The pressure recovery-adjusted aortic valve area (AVA), called the energy loss coefficient (ELCo), is theoretically a more accurate parameter for evaluating aortic stenosis (AS) severity. The aim of this study was to compare the prognostic value of ELCo with that of conventional AVA. METHODS Indexed AVA (iAVA) was measured using Doppler echocardiography in 301 asymptomatic Japanese patients with AS and preserved left ventricular ejection fractions. Sinotubular junction diameter was also measured, and the indexed ELCo (iELCo) was calculated. Patients were followed for major cardiac events, including cardiac death, ventricular fibrillation, myocardial infarction, heart failure requiring admission, and aortic valve replacement. RESULTS The mean sinotubular junction diameter was 2.5 ± 0.3 cm, and >90% of patients had sinotubular junction diameters < 3 cm. There was a quadratic correlation between iAVA and iELCo (r = 0.97, P < .001). During a median of 17.4 months of follow-up, 90 patients had major cardiac events. Statistical analysis failed to show any superiority of iELCo over iAVA for predicting major cardiac events. However, iELCo stratified high-risk patients for cardiac outcome in a subset of patients whose AS grades were classified as severe using iAVA and in those whose AS severity was inconsistent (iAVA < 0.6 cm2/m2 but mean pressure gradient < 40 mm Hg). CONCLUSIONS The calculation of iELCo may not be always required, even in patients with asymptomatic AS with small aortic roots. However, this index should be calculated in patients whose AS grading assessed by iAVA is severe and in those in whom AS severity criteria are inconsistent.

中文翻译：

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能量损失系数对无症状主动脉瓣狭窄结果的预测价值：与主动脉瓣面积的直接比较。

背景技术压力恢复调节的主动脉瓣面积（AVA），称为能量损失系数（ELCo），在理论上是用于评估主动脉瓣狭窄（AS）严重程度的更准确的参数。这项研究的目的是比较ELCo与常规AVA的预后价值。方法采用多普勒超声心动图技术对301例无症状的日本AS患者并保留左心室射血分数的AVA（iAVA）进行了测量。还测量了肾小管交界处的直径，并计算了索引的ELCo（iELCo）。跟踪患者的主要心脏事件，包括心脏死亡，心室纤颤，心肌梗塞，需要入院的心力衰竭和主动脉瓣置换。结果平均管交界处直径为2.5±0.3 cm，并且> 90％的患者的肾小管结直径<3 cm。iAVA和iELCo之间存在二次相关性（r = 0.97，P <.001）。在平均17.4个月的随访期间，有90名患者发生了严重的心脏事件。统计分析未能显示iELCo在预测重大心脏事件方面优于iAVA。但是，iELCo将高危患者的心脏结局分层，其中一部分患者通过iAVA被分类为AS级为严重，而AS程度不一致的患者（iAVA <0.6 cm2 / m2但平均压力梯度<40 mm Hg）。结论即使在无症状，主动脉根小的AS患者中，也不一定总是需要计算iELCo。然而，