Paini Anna, Boutouyrie Pierre, Calvet David, Zidi Mustapha, Agabiti-Rosei Enrico, Laurent Stéphane
Department of Pharmacology, Université Paris-Descartes, Faculté de Médecine, INSERM U652, Hôpital Européen Georges Pompidou, Paris, France.
Stroke. 2007 Jan;38(1):117-23. doi: 10.1161/01.STR.0000251796.38954.b2. Epub 2006 Dec 7.
Carotid plaque rupture depends on the various types of mechanical stresses. Our objective was to determine the multiaxial mechanical characteristics of atherosclerotic plaque and adjacent segment of the common carotid artery.
A novel noninvasive echotracking system was used to measure intima-media thickness, diameter, pulsatile strain, and distensibility at 128 sites on a 4-cm long common carotid artery segment. The study included 62 patients with recent cerebrovascular ischemic event and either a plaque on the far wall of common carotid artery (n=25) or no plaque (n=37).
The mechanical characteristics of the carotid segment devoid of plaque did not differ between the two groups. Among patients with plaque, 16 had a larger radial strain at the level of plaque than at the level of adjacent common carotid artery (pattern A: outward-bending strain). The eight patients who had an opposite pattern (inward-bending strain) were more often dyslipidemic (100% versus 56% P=0.03) and type 2 diabetic (63% versus 12%, P=0.04) than pattern A patients. Strain gradient significantly decreased in parallel with the presence of dyslipidemia and/or type 2 diabetes. Longitudinal gradients of distensibility and Young's elastic modulus were consistent with strain gradients.
Type 2 diabetes and dyslipidemia were associated with a stiffer carotid at the level of the plaque than in the adjacent common carotid artery leading to an inward-bending stress. The analysis of plaque mechanics along the longitudinal axis may afford useful information, because repetitive bending strain of an atherosclerotic plaque may fatigue the wall material and result in plaque rupture.
颈动脉斑块破裂取决于多种类型的机械应力。我们的目的是确定动脉粥样硬化斑块及颈总动脉相邻节段的多轴力学特性。
使用一种新型无创回声跟踪系统，测量一段4厘米长的颈总动脉节段上128个部位的内膜中层厚度、直径、搏动应变和扩张性。该研究纳入了62例近期发生脑血管缺血事件的患者，其中25例在颈总动脉远壁有斑块，37例无斑块。
两组中无斑块的颈总动脉节段的力学特性无差异。在有斑块的患者中，16例斑块处的径向应变大于相邻颈总动脉节段处的径向应变（模式A：向外弯曲应变）。与模式A患者相比，有相反模式（向内弯曲应变）的8例患者更常出现血脂异常（100%对56%，P = 0.03）和2型糖尿病（63%对12%，P = 0.04）。应变梯度随着血脂异常和/或2型糖尿病的出现而显著降低。扩张性和杨氏弹性模量的纵向梯度与应变梯度一致。
2型糖尿病和血脂异常与斑块处的颈动脉比相邻颈总动脉更僵硬有关，导致向内弯曲应力。沿纵轴分析斑块力学可能提供有用信息，因为动脉粥样硬化斑块的反复弯曲应变可能使血管壁材料疲劳并导致斑块破裂。
