Rizzello Vittoria
Dipartimento Cardiovascolare, Unità di Cardiologia d'Urgenza e UTIC, Azienda Ospedaliera San Giovanni Addolorata, Roma, Italy.
Eur Heart J Suppl. 2021 Oct 8;23(Suppl E):E133-E137. doi: 10.1093/eurheartj/suab108. eCollection 2021 Oct.
Aortic stenosis (AS) is defined as severe in the presence of: mean gradient ≥40 mmHg, peak aortic velocity ≥4 m/s, and aortic valve area (AVA) ≤1 cm (or an indexed AVA ≤0.6 cm/m). However, up to 40% of patients have a discrepancy between gradient and AVA, i.e. AVA ≤1 cm (indicating severe AS) and a moderate gradient: >20 and <40 mmHg (typical of moderate stenosis). This condition is called 'low-gradient AS' and includes very heterogeneous clinical entities, with different pathophysiological mechanisms. The diagnostic tools needed to discriminate the different low-gradient AS phenotypes include colour-Doppler echocardiography, dobutamine stress echocardiography, computed tomography scan for the definition of the calcium score, and recently magnetic resonance imaging. The prognostic impact of low-gradient AS is heterogeneous. Classical low-flow low-gradient AS [reduced left ventricular ejection fraction (LVEF)] has the worst prognosis, followed by paradoxical low-flow low-gradient AS (preserved LVEF). Conversely, normal-flow low-gradient AS is associated with a better prognosis. The indications of the guidelines recommend surgical or percutaneous treatment, depending on the risk and comorbidities of the individual patient, both for patients with classic low-flow low-gradient AS and for those with paradoxical low-flow low-gradient AS.
主动脉瓣狭窄（AS）在以下情况下被定义为重度：平均压差≥40 mmHg、主动脉峰值流速≥4 m/s以及主动脉瓣面积（AVA）≤1 cm²（或体表面积校正后的AVA≤0.6 cm²/m²）。然而，高达40%的患者存在压差与AVA之间的差异，即AVA≤1 cm²（提示重度AS）但压差为中度：>20且<40 mmHg（典型的中度狭窄）。这种情况被称为“低压差AS”，包括非常异质性的临床实体，具有不同的病理生理机制。鉴别不同低压差AS表型所需的诊断工具包括彩色多普勒超声心动图、多巴酚丁胺负荷超声心动图、用于定义钙化积分的计算机断层扫描，以及最近的磁共振成像。低压差AS的预后影响是异质性的。典型的低流量低压差AS[左心室射血分数（LVEF）降低]预后最差，其次是矛盾性低流量低压差AS（LVEF保留）。相反，正常流量低压差AS的预后较好。指南的适应证推荐根据个体患者的风险和合并症进行手术或经皮治疗，适用于典型低流量低压差AS患者以及矛盾性低流量低压差AS患者。
