Doucet Katie M, Burwash Ian G
Department of Medicine, Division of Cardiology, University of Ottawa Heart Institute, University of Ottawa, 40 Ruskin Street, Ottawa, Ontario, Canada, K1Y 4 W7.
Curr Treat Options Cardiovasc Med. 2015 May;17(5):378. doi: 10.1007/s11936-015-0378-x.
Severe low-gradient (LG) aortic stenosis (AS) [aortic valve area (AVA) ≤ 1.0 cm(2), mean pressure gradient (MG) < 40 mmHg] represents a frequently encountered and challenging clinical dilemma. A systematic approach, which often requires several imaging modalities, should be undertaken to confirm the hemodynamic findings and rule out measurement error. Low-flow conditions often account for the discrepancy and can be present whether the left ventricular ejection fraction (LVEF) is depressed or normal. In patients with classical low-flow (LF), LG AS in which LVEF is reduced (<40-50 %), dobutamine stress echocardiography (DSE) should be used to distinguish patients with true severe AS and pseudo-severe AS, as well as to evaluate for the presence of left ventricular contractile or flow reserve. Surgical or transcatheter aortic valve replacement (AVR) should likely be reserved for those patients with true severe AS. Patient outcome with medical or surgical management generally relates to patient functional capacity, stenosis severity, and left ventricular functional reserve. Patients with severe LG AS with preserved LVEF can have a stroke volume that is either normal (>35 mL/m(2)) or low (<35 mL/m(2)). New data suggest that DSE can identify pseudo-severe AS in up to 30 % of patients with severe LF-LG AS with preserved LVEF. AVR should likely be restricted to those patients with true severe AS, although there is currently little data to support this strategy. Symptomatic patients with severe LG AS with preserved LVEF, whether they have normal or low flow, should be offered AVR. Transcatheter AVR provides an alternative therapeutic option in the high-risk patient.
重度低跨瓣压差（LG）主动脉瓣狭窄（AS）[主动脉瓣面积（AVA）≤1.0 cm²，平均压差（MG）<40 mmHg]是临床常见且具有挑战性的难题。应采用系统方法（通常需要多种成像方式）来确认血流动力学结果并排除测量误差。低流量状态常导致这种差异，无论左心室射血分数（LVEF）降低还是正常都可能出现。在经典低流量（LF）、LVEF降低（<40% - 50%）的LG AS患者中，应使用多巴酚丁胺负荷超声心动图（DSE）来区分真正的重度AS患者和假性重度AS患者，并评估左心室收缩或血流储备情况。手术或经导管主动脉瓣置换术（AVR）可能应仅用于真正的重度AS患者。药物或手术治疗的患者预后通常与患者功能状态、狭窄严重程度和左心室功能储备有关。LVEF保留的重度LG AS患者的每搏输出量可能正常（>35 mL/m²）或较低（<35 mL/m²）。新数据表明，DSE可在高达30%的LVEF保留的重度LF - LG AS患者中识别出假性重度AS。AVR可能应仅限于真正的重度AS患者，尽管目前几乎没有数据支持这一策略。有症状的LVEF保留的重度LG AS患者，无论其流量正常还是较低，都应考虑进行AVR。经导管AVR为高危患者提供了一种替代治疗选择。
