Читать книгу Interventional Cardiology - Группа авторов - Страница 28

Technological advances enable us to visualise the extent and composition of atherosclerotic plaques in the coronary artery non‐invasively and invasively. Intravascular imaging modalities including intravascular ultrasound (IVUS), backscattered radio‐frequency (RF) IVUS, optical coherence tomography (OCT) and near‐infrared spectroscopy (NIRS) have been currently available for assessing coronary atherosclerotic plaque morphology and composition. The great advantage of intravascular imaging is that it is based on a device that is practical for use in the clinical setting, and it generates a real‐time assessment of plaque morphology. In addition, serial intravascular imaging enables us to evaluate the natural history progression of coronary atherosclerosis, which has also been used for assessing the pharmaceutical effects on coronary atherosclerosis. A number of studies have employed these techniques for detecting the factors contributing to cardiovascular events and assessing the efficacy of therapies targeting cardiovascular risk factors. These high‐risk or vulnerable atherosclerotic plaques which are defined as precursors to lesions that rupture have specific characteristics, such as large plaque burden, expansive arterial remodelling, thin cap fibroatheroma (TCFA), lipid pools, necrotic core, inflammatory cell accumulation and neovascularisation [105]. These markers of vulnerability provide potential targets for high‐risk plaque imaging. However, each intravascular imaging device has specific individual advantages and disadvantages in regards to evaluating plaque morphology and plaque compositions, shown in Table 1.1.

Figure 1.1 OCT illustration of Neoatherosclerosis. (a) Neo‐intimal hyperplasia inside the stent. A uniform layer of neo‐intima is seen covering the stent struts (white arrows) from 12 to 4 o’clock. Remainder of the stent circumference is covered by an irregular, very thick tissue layer containing dark, signal poor core consistent with lipid pool and signal rich, thick fibrous cap. (b) Lipid/ necrotic core in the neo‐atherosclerotic plaque has been highlighted in yellow.

Table 1.1 Comparison of plaque characteristics evaluation.

	IVUS	VH‐IVUS	OCT	NIRS
Imaging technology	Ultrasound	Ultrasound	Infrared	Near‐infrared
Resolution (m)	100–200	100–200	< 10	N/A
Penetration (mm)	10.0	10.0	1.0–2.5	1.0‐2.0
Plaque volume	++	–	–	–
Remodeling	++	–	–	–
TCFA detection	–	+	++	–
Calcification	++	++	++	–
Thrombus	+	–	++	–
Neovascularization	–	–	+	–
Macrophages	–	–	–	–
Cholesterol crystals	–	–	+	++
Lipid core	+	+	+	–