Department of Medicine, Section of Cardiology, University of Verona, P.le Stefani 1, 37126 Verona, Italy.
Department of Cardiovascular Disease, Mayo Clinic, 200 1st St SW, Rochester, MN 55902, Stati Uniti, USA.
Eur Heart J Cardiovasc Imaging. 2018 May 1;19(5):569-573. doi: 10.1093/ehjci/jex172.
Patients with severe aortic stenosis (AS) and normal ejection fraction (EF) can paradoxically present low-transaortic flow and worse prognosis. The role of co-existing mitral regurgitation (MR) in determining this haemodynamic inconsistency has never been quantitatively explored. The hypothesis is that MR influences forward stroke volume and characterizes the low-flow AS pattern.
Consecutive patients with indexed aortic valve area (AVA) ≤0.6 cm2/m2 and EF > 50% formed the study population. Complete echocardiographic data were collected, and mitral effective regurgitant orifice area (ERO) and regurgitant volume were obtained with proximal isovelocity surface area method. Patients were divided into subgroups according to indexed stroke volume (SV index). Included patients were 273 [age 79 ± 10 years, 53% female, EF 65 ± 7%, indexed AVA 0.47 ± 0.09 cm2/m2, mean transaortic gradient (MG) 32 ± 17 mmHg]. Mitral regurgitation was present in 89 (32%); ERO was 0.12 ± 0.08 cm2 (range 0.02-0.49 cm2). A low-flow state (SV index ≤35 mL/m2) was diagnosed in 41 (15%) patients. The prevalence of MR was higher in with low-flow vs. normal-flow group (56 vs. 28%, P = 0.03). Effective regurgitant orifice was associated to low-flow state univariately (OR: 1.75 [1.59-2.60]; P = 0.004) and after comprehensive adjustment (OR:1.76 [1.12-2.75]; P = 0.01). When MG was forced in the model, ERO remained significant (P < 0.009). On average, there was a 6 mL reduction in forward SV appeared per each 0.1 cm2 of ERO.
In patients with severely reduced AVA and preserved EF, MR is a major determinant of the low-flow condition. Furthermore, MR quantification by ERO predicts the presence of reduced flow independently of chamber volumes, systolic function, and transaortic gradient.
严重主动脉瓣狭窄（AS）伴射血分数正常（EF）的患者可能会出现反常的低跨瓣血流和更差的预后。合并性二尖瓣反流（MR）在确定这种血流动力学不一致中的作用从未被定量探讨过。假说为 MR 影响前向心搏量并使低流量 AS 模式特征化。
连续的索引主动脉瓣面积（AVA）≤0.6cm2/m2 且 EF>50%的患者构成了研究人群。收集了完整的超声心动图数据，并使用近端等速表面积法获得了二尖瓣有效反流口面积（ERO）和反流量。根据索引心搏量（SV index）将患者分为亚组。纳入的患者共 273 例[年龄 79±10 岁，53%为女性，EF 65±7%，索引 AVA 0.47±0.09cm2/m2，平均跨瓣梯度（MG）32±17mmHg]。89 例（32%）患者存在二尖瓣反流，ERO 为 0.12±0.08cm2（范围 0.02-0.49cm2）。41 例（15%）患者诊断为低流量状态（SV index≤35mL/m2）。低流量组的 MR 患病率高于正常流量组（56% vs. 28%，P=0.03）。在单变量分析中，有效反流口与低流量状态相关（OR：1.75[1.59-2.60]；P=0.004），在综合调整后仍相关（OR：1.76[1.12-2.75]；P=0.01）。当 MG 被强制纳入模型时，ERO 仍然具有显著意义（P<0.009）。平均而言，ERO 每增加 0.1cm2，前向 SV 就会减少 6mL。
在严重 AVA 降低伴 EF 保留的患者中，MR 是低流量状态的主要决定因素。此外，通过 ERO 定量评估 MR 可独立于心腔容积、收缩功能和跨瓣梯度预测低流量的存在。
