Department of Cardiology, Compiègne Hospital, Compiègne, France.
J Am Soc Echocardiogr. 2012 Aug;25(8):835-41. doi: 10.1016/j.echo.2012.05.020. Epub 2012 Jun 27.
Coronary flow reserve (CFR) is progressively impaired with aortic stenosis (AS) severity. However, there is a broad range of CFR in patients with severe AS, and the factors responsible for this variability are weakly characterized. The aim of this study was to assess the correlates of noninvasive CFR in patients with severe AS (≤1 cm(2) or ≤0.6 cm(2)/m(2)) and preserved left ventricular (LV) ejection fractions (LVEFs) (>50%).
Sixty-six consecutive patients (mean age, 74 ± 11 years; 31 women; mean LVEF, 69 ± 10%) with isolated severe AS (mean, 0.75 ± 0.2 cm(2) and 0.42 ± 0.1 cm(2)/m(2)), without coronary artery disease, underwent prospectively Doppler transthoracic echocardiography including CFR measurement in the distal part of the left anterior descending coronary artery (LAD) with intravenous adenosine infusion (140 μg/kg/min over 2 min). CFR was defined as hyperemic peak LAD flow velocity divided by baseline flow velocity. Twenty controls matched for age and gender served as a comparative group. Plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) was also assessed.
Compared with controls, patients with AS had higher baseline LAD flow velocities (36 ± 11 vs 27 ± 6 cm/sec, P < 0.01), lower hyperemic LAD flow velocities (80 ± 20 vs 89 ± 18 cm/sec, P = .09), and consequently lower CFR (2.3 ± 0.7 vs 3.3 ± 0.7, P < .01). In patients with AS, there were significant inverse correlations between CFR and age, E/e', indexed LV mass, NT-proBNP, pulmonary artery systolic pressure (PASP), baseline LV rate-pressure product, heart rate, and indexed left atrial volume and a significant positive correlation between CFR and LVEF (all P values < .05). Furthermore, compared with patients with asymptomatic AS (n = 22), those with symptomatic AS had more severely impaired CFR (2.15 ± 0.6 vs 2.7 ± 0.65), and higher NT-proBNP values (all P values < .05). In multivariate analysis, NT-proBNP, PASP, and LV rate-pressure product were the main independent correlates of CFR (all P values ≤ .01), and PASP was independently predicted by E/e' and indexed left atrial volume (all P values < .01).
In patients with severe AS and preserved LVEFs, there is a relatively broad range of CFR values. CFR is more severely impaired in patients with symptomatic AS and is mainly linked with NT-proBNP, a surrogate of increased LV wall stress, workload as measured by LV rate-pressure product, and PASP.
随着主动脉瓣狭窄（AS）严重程度的增加，冠状动脉血流储备（CFR）逐渐受损。然而，在严重 AS 患者中，CFR 存在广泛的范围，导致这种变异性的因素特征较弱。本研究的目的是评估严重 AS（≤1 cm² 或≤0.6 cm²/m²）和保留左心室（LV）射血分数（LVEF）>50%的患者中非侵入性 CFR 的相关性。
66 例连续患者（平均年龄 74±11 岁；31 名女性；平均 LVEF，69±10%）患有孤立性严重 AS（平均 0.75±0.2 cm² 和 0.42±0.1 cm²/m²），无冠状动脉疾病，前瞻性多普勒经胸超声心动图包括使用静脉内腺苷输注（2 分钟内 140μg/kg/min）测量左前降支（LAD）远端的 CFR。CFR 定义为充血时 LAD 峰值流速除以基础流速。20 名年龄和性别匹配的对照组作为对照组。还评估了血浆 N 末端脑利钠肽前体（NT-proBNP）。
与对照组相比，AS 患者的基线 LAD 流速较高（36±11 vs 27±6 cm/sec，P<0.01），充血时 LAD 流速较低（80±20 vs 89±18 cm/sec，P=0.09），因此 CFR 较低（2.3±0.7 vs 3.3±0.7，P<0.01）。在 AS 患者中，CFR 与年龄、E/e'、 indexed LV 质量、NT-proBNP、肺动脉收缩压（PASP）、基线 LV 压力-速率乘积、心率和 indexed 左心房体积呈显著负相关，与 LVEF 呈显著正相关（所有 P 值均<0.05）。此外，与无症状 AS 患者（n=22）相比，有症状 AS 患者的 CFR 受损更严重（2.15±0.6 vs 2.7±0.65），NT-proBNP 值更高（所有 P 值均<0.05）。在多变量分析中，NT-proBNP、PASP 和 LV 压力-速率乘积是 CFR 的主要独立相关因素（所有 P 值均≤0.01），而 PASP 由 E/e'和 indexed 左心房体积独立预测（所有 P 值均<0.01）。
在严重 AS 且保留 LVEF 的患者中，CFR 值范围较广。有症状 AS 患者的 CFR 受损更严重，主要与 NT-proBNP 相关，NT-proBNP 是左心室壁应力增加的替代物，由左心室压力-速率乘积和 PASP 测量的工作量表示。
