Quinze anos de ecografia intravascular coronária em intervenção coronária percutânea em Portugal

IntroductionCoronary intravascular ultrasound (IVUS) is increasingly important in catheterization laboratories due to its positive prognostic impact. This study aims to characterize the use of IVUS in percutaneous coronary intervention (PCI) in Portugal.MethodsA retrospective observational study was performed based on the Portuguese Registry on Interventional Cardiology of the Portuguese Society of Cardiology. The clinical and angiographic profiles of patients who underwent PCI between 2002 and 2016, the percentage of IVUS use, and the coronary arteries assessed were characterized.ResultsA total of 118 706 PCIs were included, in which IVUS was used in 2266 (1.9%). Over time, use of IVUS changed from none in 2002 to generally increasing use from 2003 (0.1%) to 2016 (2.4%). The age of patients in whom coronary IVUS was used was similar to that of patients in whom IVUS was not used, but in the former group there were fewer male patients, and a higher prevalence of cardiovascular risk factors (hypertension, hypercholesterolemia and diabetes), previous myocardial infarction, previous PCI, multivessel coronary disease, C‐type or bifurcated coronary lesions, and in‐stent restenosis. IVUS was used in 54.8% of elective PCIs and in 19.15% of PCIs of the left main coronary artery.ConclusionCoronary IVUS has been increasingly used in Portugal since 2003. It is used preferentially in elective PCIs, and in patients with higher cardiovascular risk, with more complex coronary lesions and lesions of the left main coronary artery.     

Use of intravascular imaging in managing coronary artery disease

For many years,coronary angiography has been considered "the gold standard" for evaluating patients with coronary artery disease. However,angiography only provides a planar two-dimensional silhouette of the lumen and is unsuitable for the precise assessment of atherosclerosis. With the introduction of intravascular imaging,direct visualization of the arterial wall is now feasible. Intravascular imaging modalities extend diagnostic information,thereby enabling more precise evaluation of plaque burden and vessel remodeling. Of all technologies,intravascular ultrasound(IVUS) is the most mature and widely used intravascular imaging technique. Optical coherence tomography(OCT) is an evolving technology that has the highest spatial resolution of existing imaging methods,and it is becoming increasingly widespread. These methods are useful tools for planning interventional strategies and optimizing stent deployment,particularly when stenting complex lesions. We strongly support the mandatory use of IVUS for left main percutaneous coronary intervention(PCI). In addition,it can be used to evaluate vascularresponses,including neointimal growth and strut apposition,during follow-ups. Adequately powered randomized trials are needed to support IVUS or OCT use in routine clinical practice and to answer whether OCT is superior to IVUS in reducing adverse events when used to guide PCI. The current perception and adoption of innovative interventional devices,such as bioabsorbable scaffolds,will increase the need for intravascular imaging in the future.     

Assessment of coronary plaque with optical coherence tomography and high-frequency ultrasound

This study compares the ability of intravascular optical coherence tomography (OCT) and high-frequency intravascular ultrasound (IVUS) to image highly stenotic human coronary arteries in vitro. Current imaging modalities have insufficient resolution to perform risk stratification based on coronary plaque morphology. OCT is a new technology capable of imaging at a resolution of 5 to 20 microm, which has demonstrated the potential for coronary arterial imaging in prior experiments. Human postmortem coronary arteries with severely stenotic segments were imaged with catheter-based OCT and IVUS. The OCT system had an axial resolution of 20 microm and a transverse resolution of 30 microm. OCT was able to penetrate and image near-occlusive coronary plaques. Compared with IVUS, these OCT images demonstrated superior delineation of vessel layers and lack of ring-down artifact, leading to clearer visualization of the vessel plaque and intima. Histology confirmed the accuracy and high contrast of vessel layer boundaries seen on OCT images. Thus, catheter-based OCT systems are able to image near-occlusive coronary plaques with higher resolution than that of IVUS.     

Intravascular ultrasound in cardiology

Intravascular ultrasound (IVUS) is a clinically useful tool that provides cross-sectional images of the coronary arterial lumen and wall. Diagnostic applications of IVUS include the evaluation of ambiguous lesions on angiography particularly at the bifurcations. IVUS is also useful in the assessment of coronary vasculopathy in cardiac transplant patients or it can help to diagnose abnormalities such as syndrome X or coronary artery spasm. IVUS can optimize the performing of percutaneous coronary interventions, especially stent implantation. It represents as well an optimal tool for assessing regression of atherosclerosis. Three-dimensional reconstruction, elastography and imaging guide wires are some of the recent advances in the field of intravascular ultrasound.     

Visualization of coronary atherosclerotic plaques in patients using optical coherence tomography: comparison with intravascular ultrasound

OBJECTIVES: The aim of this study was to evaluate the feasibility and the ability of intravascular optical coherence tomography (OCT) to visualize the components of coronary plaques in living patients. BACKGROUND: Disruption of a vulnerable coronary plaque with subsequent thrombosis is currently recognized as the primary mechanism for acute myocardial infarction. Although such plaques are considered to have a thin fibrous cap overlying a lipid pool, imaging modalities in current clinical practice do not have sufficient resolution to identify thin (< 65 microm) fibrous caps. Optical coherence tomography is a new imaging modality capable of obtaining cross-sectional images of coronary vessels at a resolution of approximately 10 microm. METHODS: The OCT images and corresponding histology of 42 coronary plaques were compared to establish OCT criteria for different types of plaques. Atherosclerotic lesions with mild to moderate stenosis were identified on angiograms in 10 patients undergoing cardiac catheterization. Optical coherence tomography and intravascular ultrasound (IVUS) images of these sites were obtained in all patients without complication. RESULTS: Comparison between OCT and histology demonstrated that lipid-rich plaques and fibrous plaques have distinct OCT characteristics. A total of 17 IVUS and OCT image pairs obtained from patients were compared. Axial resolution measured 13 +/- 3 microm with OCT and 98 +/- 19 microm with IVUS. All fibrous plaques, macrocalcifications and echolucent regions identified by IVUS were visualized in corresponding OCT images. Intimal hyperplasia and echolucent regions, which may correspond to lipid pools, were identified more frequently by OCT than by IVUS. CONCLUSIONS: Intracoronary OCT appears to be feasible and safe. Optical coherence tomography identified most architectural features detected by IVUS and may provide additional detailed structural information.     

光学相干断层成像和血管内超声在冠状动脉介入手术中的应用

目的 应用光学相干断层成像(OCT)及血管内超声(IVUS)检测技术评价冠状动脉内粥样硬化斑块的稳定性,并指导支架置入,检测血管对置入支架后即刻和中远期的反应.方法 选择2008年2-7月间的27例患者,进行冠状动脉造影、OCT及IVUS检查,共检查了30支血管,其中8处为药物支架植入术后血管,并对19处病变进行了支架置入.结果 除外支架置入的8例(置入6个月～4年)外,其余22例病变行OCT及IVUS检查,发现稳定性斑块5例,不稳定斑块17例,其中OCT检出内膜小撕裂4例(IVUS未检出,P＞0.05),冠状动脉撕裂伴夹层病变5例(IVUS检出1例,P＞0.05),血栓形成5例(IVUS检出1例,P＞0.05),偏心斑块伴薄纤维帽12例(IVUS检出2例,P＜0.01).8例曾经进行支架治疗的患者,造影、OCT和IVUS发现2例再狭窄;OCT显示支架内膜覆盖良好,IVUS小能精确看到内膜;OCT检测出1例患者有支架后瘤样扩张.对17例不稳定性斑块及2例支架再狭窄病例行支架置入术,术后支架膨胀不良发生率26.0%,OCT及IVUS检出率相同;支架贴壁不良发生率63.2%,IVUS榆出率低于OCT(10.5%比63.2%,P＜0.01);支架近远端撕裂10.5%,IVUS均不能检出;内膜脱垂发生率52.6%,IVUS检出率低于OCT(10.5%比52.6%,P＜0.05).结论 OCT与IVUS相比,在不稳定性斑块检测准确度方面明显优于IVUS,更能精确指导冠状动脉支架置人.IVUS在操作简便性及反映斑块负荷方面要优于OCT.     

光学相干断层成像与血管内超声对比检测冠状动脉斑块破裂和血栓形成

目的评价光学相干断层成像(OCT)和血管内超声(IVUS)检测冠状动脉斑块破裂和继发血栓形成的准确性。方法选择2008年2—9月间的27例患者,进行冠状动脉造影、OCT及IVUS检查,共检查了30处病变,其中8处为药物支架植入后病变,其余22处为未经介入治疗干预的病变,对其中19处病变进行了支架植入术。结果对22例未经介入治疗干预的病变行OCT及IVUS检查,结果显示OCT检出富含脂质斑块伴薄纤维帽12例,IVUS检出2例;其中斑块破裂形成内膜轻微撕裂4例,IVUS未检出;斑块破裂伴夹层形成5例,IVUS检出1例;OCT检出血栓形成5例,其中红色血栓3例,白色血栓2例,IVUS检出1例,不能判断是红色血栓还是白色血栓。结论OCT在检测不稳定斑块方面优于IVUS,在检测斑块破裂致轻微内膜撕裂或夹层形成,以及继发血栓形成方面呈现优于IVUS趋势。     

血管内超声与光学相干断层扫描在冠状动脉临界病变中的长期随访对比研究

目的:研究血管内超声(intravenous ultrasound,IVUS)与光学相干断层扫描(optical coher-ence tomography,OCT)在冠状动脉临界病变中的长期随访研究。方法:共入选经过冠状动脉造影(至少4体位造影)证实病变狭窄处于临界病变的患者90例。将入选者按照2∶1随机分为:血管内超声组(IVUS)60例,光学相干断层成像(OCT)组30例。通过血管内超声定量分析最小管腔直径、参考血管直径、最小管腔面积等参数指标;通过光学相干断层扫描分析最小管腔直径、最小管腔面积。同时依据两组检查方法不同特征确定斑块的性质进行定性亚组分析:纤维性斑块、钙化斑块及脂质斑块等,对于高危易损斑块进行冠状动脉介入治疗,术后规律服用药物,观察两组术后住院期间、30d、3个月、9个月、1年和2年的主要心血管事件。采用COX回归模型分析两组2年内免于心血管事件的差异。结果:IVUS和OCT进行亚组软斑块分析,两组测得最小管腔直径分别为[(1.84±0.06)vs.(1.84±0.13)mm,P=0.947]。另外,在最小管腔面积方面两组分别为[(4.7±0.98)vs.(4.8±1.17)mm2,P=0.853]。OCT组通过分析软斑块纤维帽厚度为(94±24.72)μm。通过COX回归模型显示,两组在免于心血管事件的差异无统计学意义(P=0.826)。结论:对于临界病变的患者,采用IVUS或OCT成像系统能够更好的分辨血管内斑块性质,尤其易识别易损斑块。对于临界病变的患者,采用介入影像学方法进行测量分析是安全的、可靠的,能更好指导临床治疗。     

Visualization of neointima formation by optical coherence tomography

Optical coherence tomography (OCT) has recently been proposed as a high-resolution imaging method. Our male patient, who had been treated with a coronary stent, died due to acute leukemia. Coronary artery images using intravascular ultrasound (IVUS) and OCT were obtained postmortem. We also compared the image of neointima formation after stent implantation evaluated by histopathological examination with that evaluated by IVUS and OCT. OCT visualized well-apposed stent struts and neointima formation, which could not be visualized completely by IVUS. OCT may be useful for monitoring structural changes after stent implantation.     

Functional assessment of coronary artery disease by intravascular ultrasound and computational fluid dynamics simulation

Clinical trials have shown that functional assessment of coronary stenosis by fractional flow reserve (FFR) improves clinical outcomes. Intravascular ultrasound (IVUS) complements conventional angiography, and is a powerful tool to assess atherosclerotic plaques and to guide percutaneous coronary intervention (PCI). Computational fluid dynamics (CFD) simulation represents a novel method for the functional assessment of coronary flow. A CFD simulation can be calculated from the data normally acquired by IVUS images. A case of coronary heart disease studied with FFR and IVUS, before and after PCI, is presented. A three-dimensional model was constructed based on IVUS images, to which CFD was applied. A discussion of the literature concerning the clinical utility of CFD simulation is provided.     

应用血管内超声显像技术评价冠状动脉病变与颈动脉病变相关性

目的 通过研究血管内超声、冠状动脉造影检查结果与体表颈动脉超声检测的颈动脉病变的相关性,分析颈动脉粥样硬化与冠心病的关系,进一步探讨颈动脉粥样硬化对冠心病发病的预测价值.方法 38例拟诊为冠心病的患者行冠状动脉造影、血管内超声和体表颈动脉超声检查,其中8例患者经冠状动脉造影和血管内超声检查未发现冠状动脉有明显狭窄病变为对照组;30例经冠状动脉造影和血管内超声检查发现冠状动脉有明显狭窄病变为冠心病组,其中不稳定型心绞痛18例,稳定型心绞痛12例.将血管内超声及冠状动脉造影检查结果与颈动脉超声指标进行分析比较.结果 30例冠心痛患者冠状动脉造影平均直径狭窄率71.21%±9.81%,血管内超声示有不同类型的动脉粥样硬化斑块,平均面积狭窄率80.88%±7.77%;8例对照组无动脉粥样硬化斑块.冠状动脉造影平均直径狭窄率与血管内超声平均面积狭窄率之间差异有显著性(P<0.01);冠状动脉造影平均直径狭窄率与血管内超声平均面积狭窄率之间有显著相关性(r=0.663,P<0.01).根据冠状动脉造影平均直径狭窄率计算的Gensini积分分别与颈动脉粥样硬化的等级积分、Crouse积分和斑块数三项指标间均有相关性(P<0.01).颈动脉斑块对冠心痛的阳性预测值为70%(21/30),阴性预测值为75%(6/8).结论 应用血管内超声显像技术能准确诊断冠状动脉斑块的性质并测量冠状动脉狭窄率;与冠状动脉造影相比,血管内超声对评价冠状动脉病变更准确.颈动脉粥样硬化严重程度与冠状动脉血管内超声检查结果有很好的相关性;颈动脉超声检测对冠心病的诊断有一定的预测价值.     

The Role of Intracoronary Plaque Imaging with Intravascular Ultrasound,Optical Coherence Tomography,and Near-Infrared Spectroscopy in Patients with Coronary Artery Disease

The development of multiple diagnostic intracoronary imaging modalities has increased our understanding of coronary atherosclerotic disease. These imaging modalities, intravascular ultrasound (IVUS), optical coherence tomography (OCT), and near-infrared spectroscopy (NIRS), have provided a method to study plaques and introduced the concept of plaque vulnerability. They are being increasingly used for percutaneous coronary intervention (PCI) optimization and are invaluable tools in research studying the pathophysiology of acute coronary syndrome (ACS), in-stent thrombosis and in-stent restenosis. IVUS has the ability to visualize the intracoronary lumen and the vessel wall and can be used to detect early atherosclerotic disease even in the setting of positive arterial remodeling. Studies supporting the use of IVUS to optimize stent deployment and apposition have shown a significant reduction in cardiovascular events. OCT provides even higher resolution imaging and near microscopic detail of plaques, restenoses, and thromboses; thus, it can identify the etiology of ACS. Ongoing trials are evaluating the role of OCT in PCI and using OCT to study stent endothelialization and neointimal proliferation. NIRS is a modality capable of localizing and quantifying lipid core burden. It is usually combined with IVUS and is used to characterize plaque composition. The benefits of NIRS in the setting of ACS have been limited to case reports and series. The utilization of all these intracoronary imaging modalities will continue to expand as their indications for clinical use and research grow. Studies to support their use for PCI optimization resulting in improved outcomes with potential to prevent downstream events are ongoing.     

Invasive imaging of the coronary atherosclerotic plaque

Coronary atherosclerosis has a high prevalence and is known as the leading cause of death worldwide. Clinically, coronary atherosclerosis is routinely evaluated by coronary angiography, which provides a luminogram of the coronary artery and allows for recognizing lumen narrowing. However, angiography does not allow for the direct assessment of the disease process within the coronary vessel wall. Today, a number of catheter-based imaging methods can overcome this shortcoming and provide physicians with additional information on specific morphological components of atherosclerotic lesions. This article discusses the abilities of intravascular imaging techniques such as intravascular ultrasound (IVUS), IVUS-VH, iMAP, integrated backscatter-IVUS, intravascular optical coherence tomography, near-infrared spectroscopy and angioscopy, to diagnose coronary atherosclerosis and their potential to guide clinical decision making.     

Clinical Utility of Intravascular Imaging: Past,Present, and Future

Although it is the tool used by most interventional cardiologists to assess the severity of coronary artery disease and guide treatment, coronary angiography has many limitations because it is a shadowgraph, depicting planar projections of the contrast-filled lumen that are often foreshortened rather than imaging the diseased vessel itself. Currently available intravascular imaging technologies include grayscale intravascular ultrasound (IVUS), optical coherence tomography (OCT) (the light analogue of IVUS), and near-infrared spectroscopy that detects lipid within the vessel wall and that has been combined with grayscale IVUS in a single catheter as the first combined imaging device. They provide tomographic or cross-sectional images of the coronary arteries that include the lumen, vessel wall, plaque burden, plaque composition and distribution, and even peri-vascular structures—information promised, but rarely provided angiographically. Extensive literature shows that these tools can be used to answer questions that occur during daily practice as well as improving patient outcomes. Is this stenosis significant? Where is the culprit lesion? What is the anatomy of an unusual or ambiguous angiographic lesion? What is the right stent size and length? What is the likelihood of distal embolization or periprocedural myocardial infarction during stent implantation? Has the intervention been optimized? Why did this stent thrombose or restenose? This review summarizes these uses of intravascular imaging as well as the outcomes data supporting their incorporation into routine clinical practice.     

药物洗脱支架断裂的影像认识

目的借助冠状动脉造影和血管内超声的影像资料,确定支架断裂的发生和类型。方法回顾性分析北京大学人民医院2 021例冠状动脉造影和183例血管内超声（IVUS）影像资料。结果共发现3例患者的6处支架断裂,其中2例经IVUS证实。3例支架断裂均发生在西罗莫司药物洗脱支架,且均发生在冠状动脉介入术后1年以内。冠状动脉造影证实4处支架断裂为完全断裂伴断裂处支架移位。IVUS证实3处支架断裂为完全断裂,2处为部分断裂;1处断裂靠近支架重叠处;1处支架断裂伴有血管瘤形成。结论冠状动脉造影和IVUS可以帮助确定支架断裂的诊断。     

Bifurkationsläsionen

Bifurcation lesions are a therapeutic challenge in the interventional treatment of coronary artery disease. Thus, consideration of anatomical aspects and selection of the most appropriate strategy for an individual bifurcation have an impact on the interventional outcome. Accordingly, assessment of the type of bifurcation stenosis, including the relevance of the side branches, vessel diameter and the angle between the two branches are critical for the optimal choice of interventional strategy. The fractional flow reserve (FFR) is a parameter that provides a measure of the severity of coronary stenosis and despite some limitations, FFR can be applied to bifurcation lesions. In addition, intravascular imaging tools, such as intravascular ultrasound (IVUS) and optical coherence tomography (OCT) can be used to determine anatomical configurations.     

冠状动脉易损斑块及其形态学检测技术的新认识

冠心病患者发生严重急性冠状动脉事件约70%是由易损斑块(VP)所致。不稳定斑块的破裂是急性冠状动脉综合征(ACS)发生的核心机制,其较冠状动脉狭窄程度及病变范围更能反映冠心病患者发生急性心血管事件。现代影像学技术的进展,特别是血管内超声(IVUS)及光学相干断层成像(OCT)对识别和判断VP的形态学特征,包括斑块的形态、成分,甚至功能状态提供了快速、可靠的信息支持,在诊断和评价冠状动脉斑块方面,高分辨率的0CT检测水平已近似于组织学检测水平。该文就VP形态学检测技术的进展和认识作一简要综述。     

Current status of hybrid intravascular ultrasound and optical coherence tomography catheter for coronary imaging and percutaneous coronary intervention

Both intravascular ultrasound (IVUS) and optical coherence tomography (OCT) play a crucial role in elucidating the pathophysiology of coronary artery disease (CAD) with the goal to improve patient outcomes of medical and/or interventional CAD management. However, no single intravascular imaging technique has been proven to provide complete and detailed evaluation of all CAD lesions due to some limitations. Although sequential use of multiple modalities may sometimes be performed, there may be issues related to risk, time, and cost. To overcome these problems, several hybrids involving dual-probe combined IVUS-OCT catheters have been developed.The aim of this review article is to demonstrate some limitations of stand-alone imaging devices for evaluation of CAD, summarize the advances in hybrid IVUS-OCT imaging devices, discuss the technical challenges, and present the potential value in the clinical setting, especially in patients receiving medical or interventional CAD management.     

Clinical utility of negative contrast intravascular ultrasound to evaluate plaque morphology before and after coronary interventions

Although intravascular ultrasound (IVUS) is used for evaluation of plaque volume and lumen size as well as detection of vessel wall structures after catheter-based interventions, differentiation between the lumen and plaque structures can be difficult. This study attempted to evaluate the efficacy of negative contrast IVUS imaging for assessment of vessel wall morphology after coronary interventions. IVUS studies were performed in 67 lesions in 66 patients before and after coronary interventions. After the baseline ultrasound imaging run, warm 5% glucose solution was injected manually through the guiding catheter into the coronary artery to washout blood from the lumen to avoid speckled reflections from red blood cells (negative contrast). Quantitative measurements were obtained and plaque morphology was assessed for the presence and extent of medial dissections and intimal flaps. There was no difference in each quantitative parameter between baseline images and negative contrast images. The vessel wall boundary was clearly delineated from the lumen, which was defined as effective negative contrast in 51 of 67 lesions (76%). The baseline images revealed plaque dissection in 9 lesions (18%) and an intimal flap in 13 lesions (25%). In addition, 4 dissections (8%) and 16 intimal flaps (31%) were visualized during the infusion of negative contrast. Additional treatment was performed in 4 lesions (8%) based on the images with negative contrast. Negative contrast IVUS was more sensitive in demonstrating a plaque fracture than were baseline images. This method is useful for enhancing the diagnostic capability of IVUS imaging and may influence the decision-making process during interventional procedures.     

Diagnostic accuracy of optical coherence tomography and integrated backscatter intravascular ultrasound images for tissue characterization of human coronary plaques.

OBJECTIVES: The purpose of the present study was to validate the diagnostic accuracy of optical coherence tomography (OCT), integrated backscatter intravascular ultrasound (IB-IVUS), and conventional intravascular ultrasound (C-IVUS) for tissue characterization of coronary plaques and to evaluate the advantages and limitations of each of these modalities. BACKGROUND: The diagnostic accuracy of OCT for characterizing tissue types is well established. However, comparisons among OCT, C-IVUS, and IB-IVUS have not been done. METHODS: We examined 128 coronary arterial sites (42 coronary arteries) from 17 cadavers; IVUS and OCT images were acquired on the same slice as histology. Ultrasound signals were obtained using an IVUS system with a 40-MHz catheter and digitized at 1 GHz with 8-bit resolution. The IB values of the ultrasound signals were calculated with a fast Fourier transform. RESULTS: Using histological images as a gold standard, the sensitivity of OCT for characterizing calcification, fibrosis, and lipid pool was 100%, 98%, and 95%, respectively. The specificity of OCT was 100%, 94%, and 98%, respectively (Cohen's kappa = 0.92). The sensitivity of IB-IVUS was 100%, 94%, and 84%, respectively. The specificity of IB-IVUS was 99%, 84%, and 97%, respectively (Cohen's kappa = 0.80). The sensitivity of C-IVUS was 100%, 93%, and 67%, respectively. The specificity of C-IVUS was 99%, 61%, and 95%, respectively (Cohen's kappa = 0.59). CONCLUSIONS: Within the penetration depth of OCT, OCT has a best potential for tissue characterization of coronary plaques. Integrated backscatter IVUS has a better potential for characterizing fibrous lesions and lipid pools than C-IVUS.