Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
Cardiology Department, AP-HP, Bichat Hospital, Paris, France; INSERM U698 and University Paris 7-Diderot, Paris, France.
J Am Coll Cardiol. 2013 Dec 17;62(24):2329-38. doi: 10.1016/j.jacc.2013.08.1621. Epub 2013 Sep 24.
With concomitant Doppler echocardiography and multidetector computed tomography (MDCT) measuring aortic valve calcification (AVC) load, this study aimed at defining: 1) independent physiologic/structural determinants of aortic valve area (AVA)/mean gradient (MG) relationship; 2) AVC thresholds best associated with severe aortic stenosis (AS); and 3) whether, in AS with discordant MG, severe calcified aortic valve disease is generally detected.
Aortic stenosis with discordant markers of severity, AVA in severe range but low MG, is a conundrum, unresolved by outcome studies.
Patients (n = 646) with normal left ventricular ejection fraction AS underwent Doppler echocardiography and AVC measurement by MDCT. On the basis of AVA-indexed-to-body surface area (AVAi) and MG, patients were categorized as concordant severity grading (CG) with moderate AS (AVAi >0.6 cm²/m², MG <40 mm Hg), severe AS (AVAi ≤0.6 cm²/m², MG ≥ 40 mm Hg), discordant-severity-grading (DG) with low-MG (AVAi ≤0.6 cm(2)/m(2), MG <40 mm Hg), or high-MG (AVAi >0.6 cm(2)/m(2), MG ≥40 mm Hg).
The MG (discordant in 29%) was strongly determined by AVA and flow but also independently and strongly influenced by AVC-load (p < 0.0001) and systemic arterial compliance (p < 0.0001). The AVC-load (median [interquartile range]) was similar within patients with DG (low-MG: 1,619 [965 to 2,528] arbitrary units [AU]; high-MG: 1,736 [1,209 to 2,894] AU; p = 0.49), higher than CG-moderate-AS (861 [427 to 1,519] AU; p < 0.0001) but lower than CG-severe-AS (2,931 [1,924 to 4,292] AU; p < 0.0001). The AVC-load thresholds separating severe/moderate AS were defined in CG-AS with normal flow (stroke-volume-index >35 ml/m(2)). The AVC-load, absolute or indexed, identified severe AS accurately (area under the curve ≥0.89, sensitivity ≥86%, specificity ≥79%) in men and women. Upon application of these criteria to DG-low MG, at least one-half of the patients were identified as severe calcified aortic valve disease, irrespective of flow.
Among patients with AS, MG is often discordant from AVA and is determined by multiple factors, valvular (AVC) and non-valvular (arterial compliance) independently of flow. The AVC-load by MDCT, strongly associated with AS severity, allows diagnosis of severe calcified aortic valve disease. At least one-half of the patients with discordant low gradient present with heavy AVC-load reflective of severe calcified aortic valve disease, emphasizing the clinical yield of AVC quantification by MDCT to diagnose and manage these complex patients.
通过多普勒超声心动图和多排 CT（MDCT）同时测量主动脉瓣钙化（AVC）负荷，本研究旨在明确：1）与主动脉瓣面积（AVA）/平均梯度（MG）关系相关的独立生理/结构决定因素；2）与严重主动脉瓣狭窄（AS）相关性最佳的 AVC 阈值；3）在 MG 不一致的 AS 中，是否可以普遍检测到严重的钙化性主动脉瓣病变。
存在不一致的严重程度标志物的 AS，即 AVA 在严重范围内但 MG 较低，是一个尚未解决的难题，未被结局研究所阐明。
646 例射血分数正常的 AS 患者行多普勒超声心动图和 MDCT 测量 AVC。基于 AVA 索引到体表面积（AVAi）和 MG，将患者分为一致性严重程度分级（CG）的中度 AS（AVAi＞0.6cm²/m²，MG＜40mmHg）、严重 AS（AVAi≤0.6cm²/m²，MG≥40mmHg）、不一致严重程度分级（DG）的低 MG（AVAi≤0.6cm²/m²，MG＜40mmHg）或高 MG（AVAi＞0.6cm²/m²，MG≥40mmHg）。
MG（29%不一致）强烈受 AVA 和流量决定，但也独立且强烈受 AVC 负荷（p＜0.0001）和全身动脉顺应性（p＜0.0001）影响。DG 患者的 AVC 负荷（中位数[四分位数范围]）相似（低 MG：1619[965 至 2528]个任意单位[AU]；高 MG：1736[1209 至 2894]AU；p=0.49），高于 CG 中度 AS（861[427 至 1519]AU；p＜0.0001），但低于 CG 严重 AS（2931[1924 至 4292]AU；p＜0.0001）。在 CG-AS 中（SV 指数＞35ml/m²），在正常流量下确定严重/中度 AS 的 AVC 负荷阈值被定义。AVC 负荷（绝对值或指数）在男性和女性中准确识别严重 AS（曲线下面积≥0.89，敏感性≥86%，特异性≥79%）。将这些标准应用于 DG 低 MG 时，至少一半的患者被确定为严重钙化性主动脉瓣疾病，无论流量如何。
在 AS 患者中，MG 通常与 AVA 不一致，并且由多种因素决定，瓣膜（AVC）和非瓣膜（动脉顺应性）独立于流量。MDCT 测量的 AVC 负荷与 AS 严重程度密切相关，可用于诊断严重钙化性主动脉瓣疾病。至少一半的低梯度不一致患者存在较重的 AVC 负荷，反映出严重的钙化性主动脉瓣疾病，强调了 MDCT 定量测量 AVC 以诊断和管理这些复杂患者的临床价值。
