Heart Institute and the Departments of Imaging and Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
Atherosclerosis. 2011 Dec;219(2):588-95. doi: 10.1016/j.atherosclerosis.2011.07.128. Epub 2011 Aug 7.
We explored whether the presence of 3 known features of plaque vulnerability on coronary CT angiography (CCTA)--low attenuation plaque content (LAP), positive remodeling (PR), and spotty calcification (SC)--identifies plaques associated with greater inducible myocardial hypoperfusion measured by myocardial perfusion imaging (MPI).
We analyzed 49 patients free of cardiac disease who underwent CCTA and MPI within a 6-month period and were found on CCTA to have focal 70-99% stenosis from predominantly non-calcified plaque in the proximal or mid segment of 1 major coronary artery. Presence of LAP (≤ 30 Hounsfield Units), PR (outer wall diameter exceeds proximal reference by ≥ 5%), and SC (≤ 3 mm long and occupies ≤ 90° of cross-sectional artery circumference) was determined. On MPI, reversible hypoperfusion in the myocardial territory corresponding to the diseased artery was quantified both as percentage of total myocardium (RevTPD(ART)) by an automatic algorithm and as summed difference score (SDS(ART)) by two experienced readers. RevTPD(ART)≥ 3% and SDS(ART)≥ 3 defined significant inducible hypoperfusion in the territory of the diseased artery.
Plaques in patients with RevTPD(ART)≥ 3% more frequently exhibited LAP (70% vs. 14%, p < 0.001) and PR (70% vs. 24%, p = 0.001) but not SC (55% vs. 34%, p = 0.154). RevTPD(ART) increased from 1.3 ± 1.2% in arteries with LAP-/PR- plaques to 3.2 ± 4.3% with LAP+/PR- or LAP-/PR+ plaques to 8.3 ± 2.4% with LAP+/PR+ plaques (p < 0.001); SDS(ART) showed a similar increase: 0.3 ± 0.7 to 2.3 ± 2.8 to 6.0 ± 3.8 (p < 0.001). Using the same LAP/PR categorization, there was a marked increase in the frequency of significant hypoperfusion as determined by both RevTPD(ART)≥ 3% (1/19 to 10/21 to 9/9, p < 0.001) and SDS(ART)≥ 3 (1/19 to 8/21 to 8/9, p < 0.001). LAP and PR, but not SC, were strong predictors of RevTPD(ART) and SDS(ART) in regression models adjusting for potential confounders.
Presence of low attenuation plaque and positive remodeling in severely stenotic plaques on CCTA is strongly predictive of myocardial hypoperfusion and may be useful in assessing the hemodynamic significance of such lesions.
我们探讨了冠状动脉 CT 血管造影术（CCTA）上 3 种已知斑块易损性特征（低衰减斑块成分[LAP]、正性重构[PR]和点状钙化[SC]）的存在是否能识别与心肌灌注成像（MPI）测量的更大诱发性心肌低灌注相关的斑块。
我们分析了 49 例在 6 个月内接受了 CCTA 和 MPI 检查且在 CCTA 上发现近端或中段 1 大冠状动脉的主要非钙化斑块中存在 70%-99%局限性狭窄的无心脏疾病患者。确定存在 LAP（≤30 亨氏单位）、PR（外壁直径比近端参考值大≥5%）和 SC（≤3mm 长且占据≤90°的血管横截面积）。MPI 上，通过自动算法定量测定病变血管对应心肌区域的可逆性低灌注，用总心肌百分比表示为 RevTPD（ART）（RevTPD（ART）），用 2 位有经验的读者的总和差值评分表示为 SDS（ART）。RevTPD（ART）≥3%和 SDS（ART）≥3%定义为病变血管区域的显著诱发性低灌注。
RevTPD（ART）≥3%的患者中，斑块更常出现 LAP（70%比 14%，p＜0.001）和 PR（70%比 24%，p=0.001），但不出现 SC（55%比 34%，p=0.154）。RevTPD（ART）从 LAP-/PR-斑块的 1.3±1.2%增加到 LAP+/PR-或 LAP-/PR+斑块的 3.2±4.3%，再增加到 LAP+/PR+斑块的 8.3±2.4%（p＜0.001）；SDS（ART）也表现出类似的增加：0.3±0.7到 2.3±2.8到 6.0±3.8（p＜0.001）。使用相同的 LAP/PR 分类，RevTPD（ART）≥3%（1/19 到 10/21 到 9/9，p＜0.001）和 SDS（ART）≥3（1/19 到 8/21 到 8/9，p＜0.001）的显著低灌注的发生率显著增加。在调整潜在混杂因素的回归模型中，LAP 和 PR 而不是 SC 是 RevTPD（ART）和 SDS（ART）的强预测因子。
CCTA 上严重狭窄斑块中存在低衰减斑块和正性重构与心肌低灌注密切相关，可能有助于评估此类病变的血流动力学意义。
