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.     

Clinical applications of optical coherence tomography

Rupture of vulnerable plaque (VP) is responsible for most coronary events. Optical coherence tomography (OCT) is a high-resolution imaging method that allows excellent characterization of atherosclerotic plaque. While this technique is limited by the need to interrupt blood flow and a shallow depth of penetration, its resolution is an order of magnitude greater than possible with intravascular ultrasound (IVUS), and it has demonstrated better sensitivity and specificity for accurately determining plaque composition. Early in vitro and in vivo experiences have affirmed the excellent quality of these images making it an attractive technology for the analysis of VP. Its high resolution likely renders it the best imaging modality currently available for the evaluation of proper stent deployment and of intracoronary pathology in the setting of percutaneous coronary interventions (PCI). Our institution is currently involved in a multicenter trial to evaluate the effectiveness of OCT when compared to IVUS in this setting. Ongoing technological improvements aim to permit rapid scanning which should alleviate its current major limitation of needing to scan in a blood-free space. OCT is a promising new technology in the evaluation of atherosclerotic plaque and coronary microstructure.     

Near‐infrared spectroscopy for intracoronary detection of lipid‐rich plaques to understand atherosclerotic plaque biology in man and guide clinical therapy

Ischaemic heart disease is the leading cause of death worldwide. The common denominator for plaques causing acute coronary syndrome (ACS) is lipid accumulation, either as a lipid core or lipid pools. An intracoronary imaging device to detect lipid‐rich plaques (LRPs) could therefore identify most of the plaques causing ACS and sudden death. Near‐infrared spectroscopy combined with intravascular ultrasound (NIRS‐IVUS) is a promising new intracoronary imaging method that is able to specifically quantify lipid accumulation measured as the lipid core burden index (LCBI). NIRS‐IVUS is highly specific for the identification of ST‐elevation myocardial infarction (STEMI) and non‐ST‐elevation myocardial infarction (NSTEMI) culprit plaques usually in the form of a circular LRP. NIRS‐IVUS may assist in defining the aetiology of coronary events. The effect of cholesterol‐lowering therapy on the lipid core can be measured in coronary plaques in patients, and NIRS‐IVUS may be a useful tool for drug development in phase II studies as a surrogate end‐point for future ACS. Plaques with a high LCBI have an increased risk of peri‐procedural events. NIRS‐IVUS can help to define the diameter and length of stents to avoid procedure‐related complications. Increased coronary LCBI predicts a higher risk of future cardiovascular events. Lipid core detection using NIRS may help to identify vulnerable plaques to treat them before they cause ACS or sudden death.     

Plaque characterization of a saphenous vein graft by near-infrared spectroscopy and histopathology in a patient with a percutaneous coronary intervention

Near-infrared spectroscopy (NIRS) is an intravascular imaging (IVUS) modality that detects lipid core plaques in the vessel wall, which are regarded as high-risk plaques for distal embolization in percutaneous coronary interventions (PCI). Saphenous vein graft (SVG) lesions have friable lipid-rich plaques and thrombus prone to distal embolization. The plaque characterization of SVG by NIRS was confirmed herein for the first time with histopathology before and after PCI. The present case was a man in his 60 s with a history of coronary artery bypass graft surgery. Coronary angiography revealed severe stenosis in multiple segments of the SVG to left circumflex artery (LCX). NIRS IVUS showed large amounts of lipidic materials at each segment before PCI. After balloon dilatation, NIRS IVUS revealed a marked reduction in yellow signals on chemography. A histopathological analysis of the captured specimen showed that it was mainly composed of fibrin and contained numerous histiocytes with foam cells, lymphocytes, and other cells, which was consistent with the histopathological findings of plaque rupture.     

光学相干断层成像在冠心病介入治疗中的应用价值

目的应用光学相干断层成像（OCT）技术评价冠状动脉内粥样硬化斑块、血管对置入支架后即刻和中远期的反应。方法20例冠心病患者,有22支血管在完成冠状动脉造影或介入治疗后进行OCT成像。同时获取23个支架OCT成像,在23个支架中有15个为支架术后4～35个月随访,其中7个为雷帕霉素药物洗脱支架,8个为金属裸支架,另外8个为支架置放后即刻成像。结果入选的20例患者均成功进行OCT检查,并获取22支血管和23个支架满意的图像。通过OCT成像清晰地显示8处纤维斑块、3处钙化斑块、9处富含脂质斑块、2处血栓形成、斑块破裂3处及血管壁上夹层、粥样硬化斑块微小裂口和夹层等。7个置入雷帕霉素药物洗脱支架后OCT随访,均未发现有明显再狭窄,支架表面有少量内膜覆盖,部分支架表面没有内膜覆盖,其中1个支架血管出现瘤样扩张、支架与血管壁分离、支架表面没有内膜覆盖,有1个支架没有充分扩张。8个金属裸支架后用OCT随访发现,所有置入金属裸支架后支架表面内膜增殖明显,其中有3个支架因为内膜过度增殖而出现再狭窄,并再次接受介入治疗。8个支架术后即刻OCT检查显示,与血管贴壁均良好、支架扩张充分有3个支架,4个支架充分扩张,但可见到斑块裂片通过支架网眼突入管腔,1个支架支撑杆分布不均,可见支架与血管壁分离,在8个支架中有2个为支架内套叠支架。结论OCT成像技术可清晰显示各种冠状动脉粥样斑块情况,并可用于评价冠状动脉介入治疗的效果。     

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.     

Intravaskul?rer Ultraschall zur Erkennung atherosklerotischer Plaques und der Plaquekomposition

Coronary atherosclerosis including acute coronary syndrome (ACS) is the leading cause of death in the western world and in the majority of patients is caused by plaque rupture in flow-limiting and non-flow-limiting angiographically intermediate stenoses. Histopathologic analyses have shown the relationship of plaque composition to acute clinical events and therefore to the vulnerability of coronary lesions. Knowledge of remodeling processes of the coronary artery has focused interest on non-flow-limiting lesions of the coronary tree. Intravascular ultrasound (IVUS) can demonstrate discrepancies between the extent of coronary atherosclerosis and angiographic imaging by in vivo plaque imaging. In addition the spectral analysis of IVUS-derived radiofrequency (RF) data enables more precise analysis of the plaque composition and plaque type.As IVUS is best able to assess stent underexpansion and malapposition the guidance of catheter-based coronary interventions plays a major role in angiographically unclear lesions even in the drug-eluting stent era. In the field of percutaneous coronary interventions (PCI) IVUS can influence the therapy and therefore optimize the stratification of patients.In terms of secondary prevention it is of great clinical importance to detect progression of coronary artery disease and moreover to predict coronary lesions with significant progression up to ACS. Coronary angiography and clinical parameters are poor surrogates to predict future events in a broad cohort of patients after PCI. In addition non-invasive imaging fails to identify coronary plaques with potential rupture and subsequent ACS. This highlights the need to identify potentially high risk lesions. However, prospective studies with IVUS-RF imaging to detect lesions that are considered to be prone to rupture showed no evidence for catheter-based invasive treatment of a non-flow-limiting high risk plaque.In the future the integrated combination of multiple technologies (e.g. IVUS-RF and optical coherence tomography) can further improve the accuracy of the analysis of high risk lesions.     

Successful Expansion of an Underexpanded Stent by Rotational Atherectomy

The current routine use of intracoronary stents in percutaneous coronary intervention (PCI) has significantly reduced rates of restenosis, compared with balloon angioplasty alone. On the contrary, small post-stenting luminal dimensions due to undilatable, heavily calcified plaques have repeatedly been shown to significantly increase the rates of in-stent restenosis. Rotational atherectomy of lesions is an alternative method to facilitate PCI and prevent underexpansion of stents, when balloon angioplasty fails to successfully dilate a lesion. Stentablation, using rotational atherectomy to expand underexpanded stents deployed in heavily calcified plaques, has also been reported. We report a case via the transradial approach of rotational-atherectomy–facilitated PCI of in-stent restenosis of a severely underexpanded stent due to a heavily calcified plaque. We review the literature and suggest rotational atherectomy may have a role in treating a refractory, severely underexpanded stent caused by a heavily calcified plaque through various proposed mechanisms.     

动脉粥样硬化易损斑块的动物模型和检测技术

动脉粥样硬化易损斑块破裂、血栓形成是急性冠状动脉综合征的发病机制已成为共识。由于缺乏理想的易损斑块的动物模型,对斑块破裂前的血清学及影像学特征研究较少,尚缺乏能够早期识别易损斑块及预防斑块破裂的最佳方法。本实验室已成功构建家兔和Apo E-/-小鼠的易损斑块模型。易损斑块的检测技术主要包括非侵入性及侵入性的影像学检测及功能学检测技术。对易损斑块的早期准确识别以便及时干预具有十分重要的临床意义。     

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.     

Comparing Optical Coherence Tomography and Intravascular Ultrasound Guidance for Percutaneous Coronary Intervention: Trends and Outcomes 2010-2019

Optical coherence tomography (OCT) and intravascular ultrasound (IVUS) optimize percutaneous coronary intervention (PCI) by characterizing lesion morphology, accurately measuring vessel dimensions, and optimizing stent characteristics. We sought to compare the utilization of OCT and IVUS to guide inpatient PCI and their relative association with in-hospital mortality and readmission rates. We queried the National Readmission Database to identify patients undergoing intracoronary imaging-guided PCI from 2010 to 2019 and compared outcomes and readmission rates between patients undergoing OCT-guided PCI and IVUS-guided PCI. Multivariable logistic regression was performed to generate adjusted odds ratios (aOR) of adverse outcomes between the 2 groups. Of 3,71,450 intracoronary imaging-guided PCI admissions, OCT (n = 12,808) was used less frequently than IVUS (n = 358,642). The use of OCT-guided PCI increased from 0.1% in 2010 to 0.6% in 2019 while the rate of IVUS-guided PCI increased from 7.2% in 2010 to 9.4% in 2019 (both ptrend <0.001). Patients undergoing OCT compared to IVUS had lower in-hospital mortality (aOR 0.69, P = 0.015) and 30-day readmission rate (aOR 0.91, P = 0.040) with no statistical difference in 90-day readmission rate (aOR 0.93, P = 0.065). Heart failure was the most common cause of 30-day and 90-day readmissions in both cohorts. There was no difference in the rate of acute kidney injury between the 2 modalities. In this in-patient admission database of intracoronary imaging-guided PCI, OCT-guided PCI during index hospitalization appears to be associated with lower in-hospital mortality and 30-day readmission rates compared to IVUS-guided PCI with no difference in terms of the 90-day readmission rates.     

Impact of Intracoronary Optical Coherence Tomography in Routine Clinical Practice: A Contemporary Cohort Study

Background/purposeGuidelines recommend intracoronary optical coherence tomography (OCT) to assess stent failure and guide percutaneous coronary intervention (PCI) but OCT may be useful for other indications in routine clinical practice.Methods/materialsWe conducted an international registry of OCT cases at two large tertiary care centers to assess clinical indications and the potential impact on decision making of OCT in clinical routine. Clinical indications, OCT findings, and their impact on interventional or medical treatment strategy were retrospectively assessed.ResultsOCT was performed in 810 coronary angiography cases (1928 OCT-pullbacks). OCT was used for diagnostic purposes in 67% (N = 542) and OCT-guided percutaneous coronary intervention in 50% (N = 404, 136 cases with prior diagnostic indication). Most frequent indications for diagnostic OCT were culprit lesion identification in suspected ACS (29%) and stent failure assessment (28%). OCT findings in the diagnostic setting influenced patient management in 74%. OCT-guided PCIs concerned ACS patients in 45%. Among the 55% with chronic coronary syndrome, long lesions >28 mm (19%), left main PCI (16%), and bifurcation PCI with side-branch-stenting (5%) were the leading indications for PCI-guidance. Post-procedural OCT findings led to corrective measures in 52% (26% malapposition, 14% underexpansion, 6% edge dissection, 3% intrastent mass, 3% geographic plaque miss).ConclusionsOCT was most frequently performed to identify culprit lesions in suspected ACS, for stent failure assessment, and PCI-guidance. OCT may impact subsequent treatment strategies in two out of three patients.     

Assessing atherosclerotic plaque morphology: comparison of optical coherence tomography and high frequency intravascular ultrasound.

BACKGROUND: OCT can image plaque microstructure at a level of resolution not previously demonstrated with other imaging techniques because it uses infrared light rather than acoustic waves. OBJECTIVES: To compare optical coherence tomography (OCT) and intravascular ultrasound (IVUS) imaging of in vitro atherosclerotic plaques. METHODS: Segments of abdominal aorta were obtained immediately before postmortem examination. Images of 20 sites from five patients were acquired with OCT (operating at an optical wavelength of 1300 nm which was delivered to the sample through an optical fibre) and a 30 MHz ultrasonic transducer. After imaging, the microstructure of the tissue was assessed by routine histological processing. RESULTS: OCT yielded superior structural information in all plaques examined. The mean (SEM) axial resolution of OCT and IVUS imaging was 16 (1) and 110 (7), respectively, as determined by the point spread function from a mirror. Furthermore, the dynamic range of OCT was 109 dB compared with 43 dB for IVUS imaging. CONCLUSIONS: OCT represents a promising new technology for intracoronary imaging because of its high resolution, broad dynamic range, and ability to be delivered through intravascular catheters.     

光学干涉断层成像系统对冠心病病变特征的评价

目的:初步探讨光学干涉断层成像(OCT)系统评价冠心病病变特征的价值。方法:分析在2005年12月行冠状动脉造影检查的同时接受OCT检查的5例冠心病患者的OCT影像特征。结果:2例不稳定型心绞痛患者中,1例右冠状动脉中段成角病变狭窄99%,OCT清晰显示血栓、钙化、纤维帽厚度及脂质斑块,介入治疗后OCT检查示支架贴壁良好,血栓消失;1例前降支狭窄50%,OCT探测到清晰的附壁血栓、最薄处纤维帽及斑块破裂。3例介入治疗后患者中,1例回旋支中远段支架内狭窄75%、2例前降支支架内狭窄50%,OCT检查精确定量再狭窄程度63.33%~87.25%,增生基质主要为纤维样组织,可见少许脂质样基质,其中回旋支支架内狭窄患者OCT检查时发生支架远段冠状动脉夹层,行回旋支远段支架置入术治疗。结论:OCT系统在评价冠心病病变特征和介入治疗结果方面具有较好的应用价值。     

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.     

Multi-modality intra-coronary plaque characterization: a pilot study

BackgroundThe risk of rupture and subsequent thrombosis of the atherosclerotic coronary plaques is related to the presence of necrotic core with high lipid content.We conducted an exploratory pilot trial to compare the capability for lipid tissue detection using four intra-coronary diagnostic techniques: greyscale intravascular ultrasound (GS IVUS), IVUS radiofrequency data (IVUS RFD) analysis, optical coherence tomography (OCT) and intravascular magnetic resonance spectroscopy (IVMR).MethodsTwenty-four matched target plaques were analyzed with the 4 techniques in non-culprit lesions in five patients with stable angina. Following IVUS pullback, OCT and IVMR was performed. Plaque composition was assessed using established criteria of each technology.ResultsAtherosclerotic plaques classified as soft by GS IVUS were mainly composed by fibro-fatty (80%) or necrotic core (20%) by IVUS RFD. These soft plaques were classified as “lipid-rich” by OCT in the majority of cases (80%). IVMR confirmed the presence of lipid with a lipid fraction index ranging between 36 and 79 in these soft plaques. Besides this good agreement for soft plaques, GS IVUS, IVUS RFD and OCT had 100% agreement in the identification of calcified plaques.ConclusionThe present study explored multi-modality imaging of atherosclerotic plaque in-vivo. Assessing specifically lipid-rich plaques, there was generally good agreement for plaque components identified as soft by traditional GS IVUS with RFD and OCT whereas IVMR showed a varying amount of lipid in these regions. Nevertheless there continues to remain inherent variation, namely as a result of the different imaging resolutions and the lack of common nomenclature and classification.     

Relationship between interleukin-18 levels and characterization of atherosclerotic plaque and percutaneous coronary intervention

Background lnterleuldn-18(IL- 18) plays a key role in the development,progression and outcome of coronary artery disease and its complications.However,its variability relation to the characterization of atherosclerotic plaque and percutaneous coronary intervention are still unknown.Methods Fifty four patients with coronary artery disease [22 patients with stable angina (SA) and 32 patients with acute coronary syndrome (ACS)] were enrolled in this study.All patients underwent percutaneous coronary intervention (PCI).The stability of the plaques at the criminal vessels was assessed with analogical IVUS.Serum IL-18 levels were measured at the time points of 5 rain before PCI,and Oh,6h,24h and lmonth after PCI in all patients.Results ACS group consisted mainly of lipidic unstable plaques while SA group of fibrous stable plaques.Moreover,compared with those in SA group,eccentricity index (EI) and remodeling index (RI) were significantly higher in ACS group.Positive remodeling was seen in ACS group while negative or no remodeling in SA group.Further,serum IL-18 levels were significantly elevated in patients with ACS than those in SA group before PCI,increased at Oh,6h,24h after PCI (P＜0.05)and were not significant different at 1 month after PCI from those before PCI.Conclusions There is significant difference in the composition and structural characteristics of atherosclerotic plaques between ACS and UA groups.PCI triggersd and enhances the inflammatory response in a short time.Serum levels of IL- 18 are the predictors of progression of unstable plaque in atherosclerosis.Post-operative complications of PCI might be reduced by inhibiting IL- 18.(J Geriatr Cardiol 2008;5:21-24)     

Assessment of coronary arterial plaque by optical coherence tomography

The purpose of this study was to analyze the ability of optical coherence tomography (OCT) to identify coronary arterial plaque diagnosed by histologic examination. We examined 166 sections from 108 coronary arterial segments of 40 consecutive human cadavers (24 men and 16 women; mean age 74 +/- 7 years). The plaque type was classified as fibrous (n = 43), fibrocalcific (n = 82), or lipid-rich (n = 41). The accuracy of OCT and intravascular ultrasound (IVUS) in characterizing the plaque type was studied, with the histologic consensus diagnosis serving as the gold standard. OCT, as well as IVUS, had high sensitivity and specificity for characterizing the different types of atherosclerotic plaque. OCT had a higher sensitivity for characterizing lipid-rich plaques than IVUS (85% vs 59%, p = 0.03). In conclusion, the high resolution of OCT permitted evaluation of lipid-rich plaques more accurately than IVUS.     

Intracoronary ultrasound in acute coronary syndromes: from characterization of vulnerable plaques to guidance of percutaneous treatment of complex stenoses

Our current knowledge on the substrate and genesis of acute coronary syndromes (ACS) results from the integration of pathological, angiographic, and intracoronary imaging techniques. To summarize briefly the current paradigm, eight differentiated stages of development of atherosclerotic lesions are currently accepted, defined not only by the cellular elements involved, but also by the appearance of sudden alterations of plaque structure and coronary thrombosis. The latter constitutes not only the dominant substrate for the most devastating manifestations of coronary artery disease, but also accelerates plaque size at a faster pace than in earlier stages. The composition of atherosclerotic plaque varies significantly along the different evolutive stages, and thus includes cellular (macrophage, smooth muscle cells) and noncellular elements (glicosaminglycan or collagen-rich cellular matrix, extracellular lipid deposits, calcification, fresh, or organized thrombus) in a varying proportion. Furthermore, a dynamic process of vessel remodeling occurs along the atherosclerotic process, resulting, in most cases, in a protective mechanism against myocardial ischemia by preserving luminal dimensions during plaque enlargement. Intravascular ultrasound (IVUS) is one of the intracoronary imaging techniques that has contributed to the understanding of these changes in man. In addition, IVUS has the potential of being a useful clinical tool for predicting the chances of future acute coronary events by identifying vulnerable plaques, of characterizing which is the culprit lesion in ACS, and in guiding revascularization procedures in the treacherous field of thrombotic coronary syndromes. In this article, we review the current evidence on the potential of IVUS imaging for fulfilling these purposes.     

Apport de l’imagerie endocoronaire dans le syndrome coronarien aigu

Acute coronary syndrome (ACS) remains a major cause of mortality and morbidity in the world, although it has considerably decreased through technical and pharmacological advances. The physiopathological approach of the ACS has progressed considerably in recent years thanks to the anatomopathological work and the data of the endocoronary imaging, in particular of the endovascular ultrasound (IVUS). Plaque rupture is the most common cause of ACS, however OCT (optical coherence tomography) studies have shown that surface plaque erosion was more common than thought. The use of OCT in the ACS may prove to be a valuable diagnostic aid: study of the culpable lesion, spontaneous coronary dissection or intramural spontaneous hematoma, stent thrombosis; from a therapeutic point of view: reduction of the risk of stent malapposition, additional technique, delayed stenting, implantation of a bioresorbable stent, medical treatment of ACS without stenting. Endocoronary imaging, especially OCT, will of course never be systematic as treatment of ACS, but providing excellent value for both diagnosis and treatment, it must be an integral part of the therapeutic arsenal available in cathlab.