Escaned J, Baptista J, Di Mario C, Haase J, Ozaki Y, Linker D T, de Feyter P J, Roelandt J R, Serruys P W
Cardiac Catheterisation and Intracoronary Imaging Laboratories, Thoraxcenter, Rotterdam, The Netherlands.
Circulation. 1996 Sep 1;94(5):966-72. doi: 10.1161/01.cir.94.5.966.
Automated stenosis analysis is a common feature of commercially available quantitative coronary angiography (QCA) systems, allowing automatic detection of the boundaries of the stenosis, interpolation of the expected dimensions of the coronary vessel at the point of obstruction, and angiographically derived estimation of atheromatous plaque size. However, the ultimate meaning of this type of analysis in terms of the degree of underlying atherosclerotic disease remains unclear. We investigated the relationship between stenosis analysis performed with QCA and the underlying degree of atherosclerotic disease judged by intracoronary ultrasound (ICUS) imaging.
In 40 coronary stenoses, automated identification of the sites of maximal luminal obstruction and the start of the stenosis was performed with QCA by use of curvature analysis of the obtained diameter function. Plaque size at these locations also was estimated with ICUS, with an additional ICUS measurement immediately proximal to the start of the stenosis. Crescentlike distribution of plaque, indicating an atheroma-free arc of the arterial wall, was recorded. At the site of the obstruction, total vessel area measured with ICUS was 16.65 +/- 4.04 mm2, whereas an equivalent measurement obtained from QCA-interpolated reference dimensions was 7.48 +/- 3.30 mm2 (P = .0001). Plaque area derived from QCA data was significantly less than that calculated from ICUS (6.32 +/- 3.21 and 13.29 +/- 4.22 mm2, respectively; mean difference, 6.92 +/- 4.43 mm2; P = .0001). At the start of the stenosis identified by automated analysis, ICUS plaque area was 9.38 +/- 3.17 mm2, and total vessel area was 18.77 +/- 5.19 mm2 (50 +/- 11% total vessel area stenosis). The arterial wall presented a disease-free segment in 28 proximal locations (70%) but in only 5 sites (12%) corresponding to the start of the stenosis and none at the obstruction (P = .0001). At the site of obstruction, all vessels showed a complete absence of a disease-free segment, and the atheroma presented a cufflike or all-around distribution with a variable degree of eccentricity.
At the site of maximal obstruction, QCA underestimated plaque size as measured with ICUS. Atherosclerotic disease was consistently present at the start of the stenosis and was used as a reference site by automated stenosis analysis. At the start of the stenosis, ICUS demonstrated a mean 50 +/- 11% total vessel area stenosis, with a characteristic loss of disease-free arcs of arterial wall present in proximal locations. Thus, the site identified by automated stenosis analysis as the start of the stenosis does not represent a disease-free site but rather the place where compensatory vessel enlargement fails to preserve luminal dimensions, a phenomenon that seems related to the observed loss of a remnant arc of normal arterial wall.
自动狭窄分析是市售定量冠状动脉造影（QCA）系统的一项常见功能，可自动检测狭窄边界，在梗阻部位对冠状动脉血管的预期尺寸进行插值，并通过血管造影对动脉粥样斑块大小进行估算。然而，这种类型的分析对于潜在动脉粥样硬化疾病程度的最终意义仍不明确。我们研究了QCA进行的狭窄分析与冠状动脉内超声（ICUS）成像判断的潜在动脉粥样硬化疾病程度之间的关系。
在40处冠状动脉狭窄中，通过对获得的直径函数进行曲率分析，使用QCA自动识别最大管腔梗阻部位和狭窄起始部位。这些位置的斑块大小也通过ICUS进行估算，并在狭窄起始部位紧邻处额外进行一次ICUS测量。记录了斑块的新月形分布，表明动脉壁存在无粥样斑块弧。在梗阻部位，ICUS测量的总血管面积为16.65±4.04mm²，而从QCA插值参考尺寸获得的等效测量值为7.48±3.30mm²（P = 0.0001）。从QCA数据得出的斑块面积显著小于ICUS计算得出的面积（分别为6.32±3.21和13.29±4.22mm²；平均差异为6.92±4.43mm²；P = 0.0001）。在自动分析确定的狭窄起始部位，ICUS斑块面积为9.38±3.17mm²，总血管面积为18.77±5.19mm²（总血管面积狭窄50±11%）。动脉壁在28个近端位置（70%）呈现无病变节段，但在与狭窄起始部位对应的位置仅5处（12%）有，在梗阻部位则无（P = 0.0001）。在梗阻部位，所有血管均显示完全没有无病变节段，粥样斑块呈袖状或环绕分布，偏心程度各异。
在最大梗阻部位，QCA低估了ICUS测量的斑块大小。动脉粥样硬化疾病在狭窄起始部位始终存在，且自动狭窄分析将其用作参考部位。在狭窄起始部位，ICUS显示总血管面积平均狭窄50±11%，近端位置存在动脉壁无病变弧的特征性缺失。因此，自动狭窄分析确定为狭窄起始部位的地方并非无病变部位，而是代偿性血管扩张未能维持管腔尺寸的地方，这一现象似乎与观察到的正常动脉壁残余弧的缺失有关。
