冠状动脉光学相干断层成像与血管内超声成像临床应用进展

光学相干断层成像技术和血管内超声成像技术是现行两种主要的冠状动脉血管内成像技术。光学相干断层成像技术具有分辨率高,组织相关性良好等特点;血管内超声成像技术具有穿透性高,成像范围广等特点。在临床应用中,两种技术有着各自的优势,两者的结合应用可以提供更多的一临床信息。现就不同临床应用中光学相干断层成像技术与血管内超声成像技术的评价能力进行对比,并对光学相干断层成像技术与血管内超声成像技术的结合应用进行简要介绍。     

血管内照射对经皮冠脉球囊成形术后再狭窄的影响

经皮冠脉球囊成形术后再狭窄机制复杂,血管平滑肌细胞增殖是导致再狭窄的主要机制之一。β、γ放射源血管内照射治疗均能抑制新生内膜增生,促进血管平滑肌细胞凋亡,能有效降低再狭窄,为预防临床经皮冠脉球囊成形术后再狭窄提供了有效手段。     

Coronary artery disease: arterial remodelling and clinical presentation

OBJECTIVE—To investigate the hypothesis that in coronary artery disease large plaques in compensatorily enlarged segments are associated with acute coronary syndromes, whereas smaller plaques in shrunken segments are associated with stable angina pectoris.METHODS—Patients selected for percutaneous transluminal coronary angioplasty (PTCA) were divided into two groups, one with stable angina pectoris (stable group, n = 37) and one with unstable angina or postmyocardial infarction angina of the infarct related artery (unstable group, n = 32). In both groups, remodelling at the culprit lesion site was determined by intravascular ultrasound before the intervention. Remodelling was calculated as relative vessel area: [vessel area culprit lesion site ÷ mean vessel area of both proximal and distal reference sites] × 100%. Compensatory enlargement was defined as remodelling of ? 105%, whereas shrinkage was defined as remodelling of ? 95%.RESULTS—In the unstable group, the vessel area at the culprit lesion site was larger than in the stable group, at mean (SD) 18.1 (5.3) v 14.6 (5.4) mm² (p = 0.008). Lumen areas were similar. Consequently, plaque area and percentage remodelling were larger in the unstable group than in the stable group: mean (SD) 14.8 (4.8) v 11.6 (4.9) mm² (p = 0.009) and 112 (31)% v 95 (17)% (p = 0.005), respectively. Significantly more culprit lesion sites were classified as shrunken in the stable group (21/37) than in the unstable group (8/32; p = 0.014). On the other hand, more lesion sites were classified as enlarged in the unstable group (16/23) than in the stable group (8/37; p = 0.022).CONCLUSIONS—In patients selected for PTCA, the mode of remodelling is related to clinical presentation.     

血管内超声在冠状动脉介入治疗中的应用进展

血管内超声显像是近10年来开展的一项新技术,不仅能够准确反映血管腔的变化同时也能清晰显示动脉管壁的解剖结构和斑块特征。随着冠状动脉介入治疗的普及,血管内超声显像在冠状动脉粥样硬化性心脏病的诊断与治疗中发挥着越来越重要的作用,现已成为诊断冠状动脉粥样硬化性心脏病新的"金标准"。它不但能更准确地测量冠状动脉狭窄的严重程度、血管腔的大小、病变长度,以帮助选择更合理的治疗策略,而且可以用于指导支架置入、评价支架内膜增生、探讨支架内再狭窄以及支架贴壁不良和支架内血栓的检出等。现回顾近几年的研究,就血管内超声显像在冠状动脉介入治疗中的应用做一综述。     

Coronary Artery Shape and Flow Changes Induced by Myocardial Bridging

Changes in coronary shape and blood flow induced by myocardial bridging were analyzed in a 56-year-old patient with symptoms of unstable angina after the exclusion of other heart disease. Coronary angiography demonstrated a 1.8-cm long myocardial bridge in the middle part of the left anterior descending coronary artery. In systole, an eccentric compression of the artery occurred, resulting in a stenosis that occupied 86% of the diameter and 96% of the area. Intraluminal ultrasound was performed with a 20-MHz transducer in a 4.8-Fr catheter sheath (Boston Scientific Corp.) connected to an ultrasound console (Diasonics Inc.). A side saddle catheter was introduced into the left anterior descending coronary artery via a giant guiding catheter. A circular shape with typical systolic pulsation was seen in the proximal part of the artery (maximal and minimal diameters 3.6 mm and 3.5 mm, respectively). Distally an eccentric compression of the coronary artery was visualized, decreasing one diameter from 3.0 to 2.6 mm, whereas the orthogonal diameter remained constant at 3.3 mm. The myocardial bridge compressed 160°–180° of the circumference of the artery, leading to a change from a circular to an elliptical arterial shape. A delayed relaxation of the bridging was demonstrated. Only the proximal part of the vessel in the muscle bridge could be passed. Coronary flow was measured using a Doppler 3-Fr 20-MHz catheter (Millar Instruments Inc.) using a pulse repetition rate of 62.5 kHz. Coronary flow velocity was calculated in the proximal part of the left anterior descending coronary artery before and after intracoronary injection of 10 mg papaverine. Phasic coronary flow velocity increased from 14 to 21 cm/sec and mean flow from 6 to 13.5 cm/sec, yielding an estimated flow reserve of 1.5 and 2.2, respectively (normal > 3.0). Thus, intravascular and Doppler ultrasound are useful techniques for analyzing the effect of myocardial bridging on changes in coronary shape and blood flow. An eccentric compression of the coronary artery was visualized with delayed relaxation. Coronary flow reserve was reduced. Further studies in larger patient populations are necessary to demonstrate whether reduction of coronary flow reserve is, in general, related to delayed relaxation in diastole.     

Coronary blood flow velocities during rotational atherectomy

This study was designed to evaluate the alterations in doppler derived coronary blood flow velocities and flow reserve following rotational ablation. Changes in doppler derived coronary blood flow velocity variables have been valuable in assessing the physiological outcome following coronary balloon angioplasty. Rotational ablation's mechanism of plaque removal could alter distal vascular bed characteristics, and, as a result, intracoronary blood flow velocities and the coronary flow reserve. A 12-MHz doppler guidewire recorded intracoronary phasic velocities and coronary flow reserve (as assessed by the hyperemic response to adenosine [12–18 mcg intracoronary]) in 28 patients, before and after rotational ablation of 30 lesions. Adjunctive balloon angioplasty was performed in 27 of 28 patients (96%). Rotational ablation and adjunctive balloon angioplasty successfully reduced the lesion diameter (87 ± 9% to 14 ± 11%; P < 0.001). A significant increase in the mean distal average peak velocity (25 ± 13 cm/sec, before; 47 ± 22 cm/sec, after; P < 0.001), and decrease in the proximal to distal average peak velocity ratio, (2.1 ± 1.3; to 1.2 ± 0.4; P = 0.002) was recorded. The mean distal diastolic to systolic velocity ratio (before, 1.4 ± 0.7; after, 1.6 ± 0.8; P = 0.44) and the coronary flow reserve (before, 1.6 ± 0.6; after, 1.5 ± 0.5; P = 0.34) did not increase despite increases in distal velocities, following successful intervention. Doppler derived distal coronary blood flow velocities increased following rotational ablation and adjunctive balloon angioplasty, with resolution of transstenotic velocity gradient. Changes in distal phasic velocity pattern and coronary flow reserve, immediately after the intervention, were not useful in the assessment of the functional outcome and may be related to abnormalities in distal vascular bed vasoreactivity produced by rotational ablation. Cathet. Cardiovasc. Diagn. 41:152–156, 1997. © 1997 Wiley-Liss, Inc.     

血管内超声——诊断和指导冠状动脉粥样硬化及其介入治疗的“金标准”

随着微型导管超声换能器和声学成像技术的飞速进步,血管内超声检查已由实验研究阶段逐步发展成为冠心病临床诊断和介入治疗中具有重要价值的新方法。血管内超声利用安装在心导管顶端的微型超声换能器,在血管内发射和接收高频超声信号,实时显示血管的切面图像,能清晰显示管壁结构的厚度、管腔大小和形态等,甚至可以辨认钙化、纤维化和脂质池等病变。现就血管内超声的发展历程、应用现状和发展前景作一简略论述。     

冠状动脉粥样硬化斑块组织定征:血管内超声研究现状

传统血管内超声对斑块仅可定性为软斑块、纤维斑块和钙化斑块,利用射频数据尚可分析反射波或背向散射的频谱参数以确定斑块构成信息.虚拟组织学作为一种新的组织超声分析技术,在射频数据分析的基础上通过彩色编码以不同颜色来区分不同的斑块成分,绿色代表纤维组织,黄色代表纤维脂质,白色代表钙化组织,红色代表坏死组织.血管内超声弹性图是评价局部斑块弹性的新技术,该技术基于组织受压产生变形的弹性原理,可用以检出斑块并评价其破裂趋势或弹性物质构成.     

血管内超声在冠状动脉药物洗脱支架晚期血栓研究中的应用

药物洗脱支架与金属裸支架相比,减少了再狭窄的发生率,但其长期安全性却引起了人们的注意。支架置入30 d以后出现的晚期支架内血栓问题成为目前介入心脏病学的研究热点。晚期支架内血栓发生率低,但一旦发生后果严重。有研究显示其发生的原因可能包括动脉的延迟愈合、动脉瘤形成及支架贴壁不良等。现就血管内超声在冠状动脉药物洗脱支架晚期血栓研究中的应用进展做一评述。     

Coronary plaque morphology affects stent deployment: Assessment by intracoronary ultrasound

The purpose of this study was to evaluate the changes in arterial wall morphology induced by coronary stent implantation and the influence of plaque morphology on stent expansion by intravascular ultrasound. Intravascular ultrasound imaging was performed in 25 lesions before and after Palmaz-Schatz stent implantation. In the 25 lesions with ultrasound images before and after stent deployment angiographic percent diameter stenosis decreased from 71% ± 11% to 6% ± 14%. By ultrasound there was a gain in luminal area from 2.0 mm² ± 1.5 mm² to 6.6 mm² ± 2.1 mm² owing to a gain in external elastic membrane area of 2.5 mm² ± 1.7 mm² and reduction of plaque area of 2.1 mm² ± 1.7 mm². Calcified lesions (n = 8) showed significantly less relative luminal gain (218% ± 128% vs. 421% ± 276%, P = .01), and stent expansion was significantly less symmetric (minimal/maximal stent diameter 0.8 ± 0.1 vs. 0.9 ± 0.1, P = .002) as compared to non-calcified lesions (n = 17). The difference in lumen area within the stent between the previously stenotic area and the ends of the stent was significantly larger in calcified lesions as compared to non-calcified lesions (29 ± 28% vs. 8 ± 23%, P = .03). Both vessel stretch and plaque reduction contribute to the luminal gain after coronary stenting. Calcified lesions interfere with optimal stent expansion. © 1996 Wiley-Liss, Inc.     

血管内超声在冠状动脉临界病变诊断及治疗中的应用

血管内超声是近年来发展起来的一项新的影像学技术,在冠心病的诊断与治疗中有着重要的应用价值,尤其对临界病变的评估有着很好的指导作用。该项技术的问世,不仅使冠状动脉临界病变的检出越来越多,而且在识别易损斑块方面有着突出的贡献,从而指导冠心病临界病变患者选择合适的治疗方案,进行及早干预,减少心血管事件的发生。因此,在冠状动脉造影中应用血管内超声检查已然成为目前诊断和治疗冠状动脉临界病变的热点问题。     

冠状动脉粥样硬化斑块消退研究进展

冠状动脉粥样硬化的发生与低密度脂蛋白及炎症反应、内皮功能减退等有关。近年来多项临床试验证实早期强化应用他汀类药物可以通过降低低密度脂蛋白、抗炎、改善内皮功能等途径改善急性冠脉综合征患者的预后。其中他汀类药物发挥的抗炎症反应、改善内皮功能等多效性作用日益受到重视。而应用血管内超声的研究发现强化他汀类治疗能够显著遏制甚至消退冠状动脉粥样斑块。     

Three-Dimensional Fluid Dynamical Features of Coronary Plaque Rupture Provoking Acute Coronary Syndrome

Aim: Coronary plaque rupture is the main cause of acute coronary syndrome (ACS), but the role of blood flow features around plaque rupture for ACS is still unknown. The present study aimed to assess the relationship between the geometric configuration of ruptured plaque and ACS occurrence using computational fluid dynamics (CFD) by moving particle method in patients with coronary artery disease. Methods: In this study, 45 patients with coronary artery disease who underwent three-dimensional intravascular ultrasound (IVUS) and had a coronary ruptured plaque (24 plaques with provoked ACS, 21 without) were included. To compare the difference in blood flow profile around ruptured plaque between the patients with and without ACS, the IVUS images were analyzed via the novel CFD analysis. Results: There were no significant differences in localized flow profile around ruptured plaque between the two groups when the initial particle velocity was 10.0 cm/s corresponded to a higher coronary flow velocity at ventricular diastole. However, when it was 1.0 cm/s corresponded to lower coronary flow velocity at ventricular systole, particles with lower velocity (0 ≤ V ≤ 5 cm/s) were more prevalent around ACS-PR ( p =0.035), whereas particles with higher velocity (10 ≤ V ≤ 20 cm/s) were more often detected in silent plaque ruptures ( p =0.018). Conclusions: Three-dimensional IVUS revealed that coronary plaque rupture was a complex one with a wide variety of its stereoscopic configuration, leading to various patterns of the local coronary flow profile. A novel CFD analysis suggested that the local flow was more stagnant around ACS-provoked ruptures than in silent ones.