University of Ottawa Heart Institute, Ottawa, Ontario, Canada.
Division of Cardiology, Mayo College of Medicine, Mayo Clinic, Rochester, MN, United States of America.
Prog Cardiovasc Dis. 2018 Nov-Dec;61(5-6):416-422. doi: 10.1016/j.pcad.2018.11.006. Epub 2018 Nov 13.
Up to 1/3 of patients with both reduced or preserved left ventricular ejection fraction (LVEF), harbor a mean pressure gradient (MPG) < 40 mm Hg (peak velocity (PV) < 4 m/s), suggesting moderate aortic stenosis (AS) and an aortic valve area (AVA) < 1 cm suggesting severe AS raising uncertainties regarding AS severity and appropriate management. In patients with reduced LVEF, increased transvalvular flow and stroke volume ≥ 20% (i.e. contractile reserve) during low-dose dobutamine echocardiography enables distinguishing patients with "true-severe AS" (severe AS with secondary LV dysfunction, PV ≥ 4 m/s or MPG > 30-40 mm Hg at peak while AVA remains <1 cm) from patients with "pseudo-severe AS" (moderate AS with associated LV dysfunction due to ischemic or dilated cardiomyopathy, AVA at peak ≥1 cm with a MPG < 30-40 mm Hg). However, interpretation of dobutamine stress echocardiography is often challenging, and absence of contractile reserve is observed in 20 to 30% of patients. Measurement of the degree of calcification (AVC) using computed tomography is an accurate and flow-independent method for the assessment of AS severity. A score > 1250 AU in women and >2000 UA in men strongly suggest severe AS. Combination of dobutamine echocardiography and AVC scoring enables assessment of AS severity with high confidence. The subset of patients with discordant grading and preserved LVEF is heterogenous and encompasses various conditions. A minority harbor a low flow state related to a reduced myocardial performance, an increased arterial afterload or combination of both. A low flow state is an important prognostic factor but does not provide any information regarding AS severity. Similarly to patients with reduced LVEF, assessment of the degree of AVC seems the best method to differentiate patients with pseudo-severe AS from patients with true severe AS. The latter should be referred for an intervention if symptomatic whereas the optimal management of the former subset remains uncertain.
高达 1/3 的左心室射血分数（LVEF）降低或保留的患者存在平均压力梯度（MPG）<40mmHg（峰值速度（PV）<4m/s），提示中重度主动脉瓣狭窄（AS），而瓣口面积（AVA）<1cm 提示重度 AS，这使得 AS 严重程度和适当治疗的不确定性增加。在 LVEF 降低的患者中，低剂量多巴酚丁胺超声心动图检查时跨瓣血流和心排量增加≥20%（即收缩储备），可区分“真性重度 AS”（LV 功能障碍继发的重度 AS，PV≥4m/s 或 MPG 在峰值时>30-40mmHg 而 AVA 仍然<1cm）与“假性重度 AS”（LV 功能障碍相关的中重度 AS，缺血性或扩张型心肌病，峰值时 AVA≥1cm 但 MPG<30-40mmHg）。然而，多巴酚丁胺负荷超声心动图的解读常常具有挑战性，并且 20%至 30%的患者观察不到收缩储备。使用计算机断层扫描测量钙化程度（AVC）是评估 AS 严重程度的一种准确且与血流无关的方法。女性 AVC 评分>1250AU 和男性>2000UA 强烈提示重度 AS。多巴酚丁胺超声心动图和 AVC 评分的联合使用可高度准确地评估 AS 严重程度。在 LVEF 保留且分级不一致的患者亚组中，患者存在异质性，包括各种情况。少数患者存在与心肌功能降低、动脉后负荷增加或两者兼有的低血流状态。低血流状态是一个重要的预后因素，但不提供任何关于 AS 严重程度的信息。与 LVEF 降低的患者类似，评估 AVC 程度似乎是区分真性重度 AS 和假性重度 AS 患者的最佳方法。如果有症状，后者应接受介入治疗，而前者的最佳管理仍不确定。
