Intravascular Optical Coherence Research Articles

Predictors of Adverse Prognosis in Patients With Acute Coronary Syndrome Caused by Plaque Erosion With a Nonstent Strategy.

Background The EROSION (Effective Anti-Thrombotic Therapy Without Stenting: Intravascular Optical Coherence Tomography-Based Management in Plaque Erosion) study demonstrated that antithrombotic therapy without stenting was safe and feasible in selected patients with acute coronary syndrome caused by plaque erosion. However, the factors related to the prognosis of these patients are not clear. This study aimed to explore the predictors of an adverse prognosis of a nonstent strategy in a larger sample size. Methods and Results A total of 252 (55 patients were from the EROSION study) patients with acute coronary syndrome with plaque erosion who met the inclusion criteria of the EROSION study and completed clinical follow-up were enrolled. Patients were divided into 2 groups according to the occurrence of major adverse cardiovascular events (MACE), which were defined as the composite of cardiac death, recurrent myocardial infarction, ischemia-driven target lesion revascularization, rehospitalization because of unstable or progressive angina, major bleeding, and stroke. Among 232 patients with acute coronary syndrome included in the final analysis, 50 patients (21.6%) developed MACE at a median follow-up of 2.9 years. Compared with patients without MACE, patients with MACE were older and had a higher degree of percentage of area stenosis (72.2%±9.4% versus 64.2%±15.7%, P<0.001) and thrombus burden (24.4%±10.4% versus 20.4%±10.9%, P=0.010) at baseline. Multivariate Cox regression analysis confirmed that age, percentage of area stenosis, and thrombus burden were predictors of MACE. The best cutoff values of predictors were age ≥60 years, percentage of area stenosis ≥63.5%, and thrombus burden ≥18.5%, respectively, and when they were all present, the rate of MACE rose to 57.7%. Conclusions The nonstent treatment strategy of patients with acute coronary syndrome caused by plaque erosion was heterogeneous, and patients aged ≥60 years, percentage of area stenosis ≥63.5%, and thrombus burden ≥18.5% may predict a worse clinical outcome.

The Continuum of Invasive Techniques for the Assessment of Intermediate Coronary Lesions.

Ischemic heart disease is one of the most important causes of mortality and morbidity worldwide. Revascularization of coronary stenosis inducing ischemia, either by percutaneous or surgical intervention, significantly reduces major adverse cardiovascular events and improves quality of life. However, in cases of intermediate lesions, classified by a diameter stenosis between 50 and 90% by European guidelines and 40–70% in American counterparts with no clear evidence of ischemia, the indication of revascularization and impact is determined using various methods that altogether comprehensively evaluate the lesions. This review will discuss the various techniques to assess intermediate stenoses, highlighting indications and advantages, but also drawbacks. Fractional flow rate (FFR) and instantaneous wave-free ratio (iFR) are the gold standard for the functional evaluation of intermediate lesions, but there are clinical circumstances in which these pressure-wire-derived indices are not accurate. Complementary invasive investigations, mainly intravascular ultrasound and/or optical coherence tomography, offer parameters that can be correlated with FFR/iFR and additional insights into the morphology of the plaque guiding the eventual percutaneous intervention in terms of length and size of stents, thus improving the outcomes of the procedure. The development of artificial intelligence and machine learning with advanced algorithms of prediction will offer multiple scenarios for treatment, allowing real-time selection of the best strategy for revascularization.

Intravascular polarization-sensitive optical coherence tomography based on polarization mode delay

Intravascular polarization-sensitive optical coherence tomography (IV-PSOCT) provides depth-resolved tissue birefringence which can be used to evaluate the mechanical stability of a plaque. In our previous study, we reported a new strategy to construct polarization-sensitive optical coherence tomography in a microscope platform. Here, we demonstrated that this technology can be implemented in an endoscope platform, which has many clinical applications. A conventional intravascular OCT system can be modified for IV-PSOCT by introducing a 12-m polarization-maintaining fiber-based imaging probe. Its two polarization modes separately produce OCT images of polarization detection channels spatially distinguished by an image separation of 2.7 mm. We experimentally validated our IV-PSOCT with chicken tendon, chicken breast, and coronary artery as the image samples. We found that the birefringent properties can be successfully visualized by our IV-PSOCT.

Potential of optical coherence tomography and intravascular ultrasound in the detection of vulnerable plaques in coronary arteries

Intravascular imaging of vulnerable plaques in vivo has great potential for predicting coronary events. Currently, there are several methods of intravascular imaging, which make it possible to verify the components of the plaque and, accordingly, its vulnerability. The most common are virtual-histology intravascular ultrasound and optical coherence tomography. Several studies have shown that these imaging techniques can stratify the risk of adverse cardiovascular events, as well as assess the effectiveness of drug therapy. This article will describe the advantages and disadvantages of intravascular ultrasound and optical coherence tomography in identifying vulnerable coronary lesions.

Debate: Intravascular ultrasound and optical coherence tomography in percutaneous revascularization. The OCT expert perspective

Debate: Intravascular ultrasound and optical coherence tomography in percutaneous revascularization. The OCT expert perspective

Debate: Intravascular ultrasound and optical coherence tomography in percutaneous revascularization. The IVUS expert perspective

Debate: Intravascular ultrasound and optical coherence tomography in percutaneous revascularization. The IVUS expert perspective

Comparison of outcomes between imaging guided versus angiography guided percutaneous coronary intervention in patients with acute coronary syndrome: insights from the national inpatient sample

Abstract Objective Coronary intravascular imaging allows visualization and characterization of vessel wall. Percutaneous coronary intervention (PCI) using intravascular ultrasound or optical coherence tomography has optimized stent deployment techniques, reduced periprocedural outcomes and reduced long-term major cardiovascular events. We sought to investigate the outcomes of imaging guided to conventional angiography guided PCI with reference to in-hospital mortality, hospital length of stay (LOS) and total hospital charge. Methods We performed a retrospective cohort study using data from the 2016–2017 Nationwide Inpatient Sample (NIS) which is the largest collection of inpatient hospitalization data in the United States. Patients admitted with a principal diagnosis of acute coronary syndrome (ACS) who underwent PCI with and without intravascular imaging was determined using the International Classification of Diseases, Tenth revision codes. The primary outcome was inpatient mortality while secondary outcomes are showed in table 1. STATA software was used for the analysis. Multivariate logistic and linear regression models were used to adjust for confounders. Results There were over 71 million hospital discharges in the combined 2016 and 2017 NIS database. Admission for ACS in adult patients (aged ≥18 years) who underwent PCI yielded 622,855 results. Among this group, 27, 520 (4.4%) had imaging guided PCI while 595,335 (95.6%) had PCI without imaging. Patients with imaging guided PCI had lower inpatient mortality (3.2% vs 2.3%, AOR: 0.74, 95% CI 0.60–0.90, p=0.004) compared to PCI with angiographic data alone. Imaging guided PCI had an adjusted increased mean LOS of 0.16 days (3.8 vs 3.7 days, CI: 006–0.26, p=0.002) with an adjusted increased mean total hospital charge of $13, 206 ($120,203 vs $104,916, p= &amp;lt;0.0001). Conclusion Patients hospitalized for ACS who had imaging guided PCI had reduced inpatient hospital mortality compared to those who had PCI without imaging guidance. Overall utilization of imaging was less than 5% in 2016–2017, however it is expected to be higher in recent years with improvements in clinical practice, training and available scientific evidence. Funding Acknowledgement Type of funding sources: None.

TCTAP C-098 Use of Intravascular Lithotripsy in Calcium Management: Comparison of Intravascular Ultrasound and Optical Coherence Tomography Guidance

TCTAP C-098 Use of Intravascular Lithotripsy in Calcium Management: Comparison of Intravascular Ultrasound and Optical Coherence Tomography Guidance

Serial evaluation of cardiac allograft vasculopathy after heart transplantation by dual-modality intravascular ultrasound and optical coherence tomography

Abstract Background Cardiac allograft vasculopathy is a combination of the development of de novo plaque and the progression of donor-transmitted plaque. Purpose This study aimed to evaluate the development of de novo plaque and the progression of donor-transmitted plaque within 12-month after heart transplantation (HTx) using serial intravascular ultrasound (IVUS) and optical coherence tomography (OCT). The association between inflammatory cytokines and plaque progression was also examined. Methods We prospectively enrolled 40 recipients to conduct serial three-vessel IVUS and OCT analysis at 8-week and 12-month after HTx. De novo plaque was defined as having maximum intimal thickness (MIT) ≥0.5 mm at 12-month in the absence of donor-transmitted plaques (MIT ≥0.5 mm at 8-week). Serum cytokines were screened with a bead-based multiplex assay. Results A total of 13 de novo plaques (fibrous, n=10; fibroatheroma, n=3) were detected in eight recipients. Serum interleukin (IL)-31 at 8-week was associated with the development of de novo plaques (p=0.009). A total of 31 donor-transmitted plaques (fibrous, n=12; fibroatheroma, n=11; fibrocalcific, n=8) were detected in 17 recipients. Multiple regression analysis revealed that fibrous (p=0.026) and fibroatheroma (p=0.012) observed at 8-week were significantly associated with subsequent plaque progression within 12-month after HTx. ΔPlaque burden was significant higher in de novo plaque than donor-transmitted plaque (38.8% [29.6–41.2] versus 8.7% [1.3–13.6], p&amp;lt;0.001). The prevalence of macrophage accumulation was lower in de novo plaque than in donor-transmitted plaque (8% versus 52%, p=0.006). Serum IL-31 at 8-week was correlated with the progression of donor-transmitted plaque as well as de novo plaque (r=0.663, p=0.029) although other cytokines like IL-1β, IL-6, IL-17, and tissue necrotic factor alpha were not. Conclusions In de novo plaques, fibrous plaque was the most common and macrophage accumulation was rarely observed. In donor-transmitted plaque, fibrous and fibroatheroma were independent predictor for the subsequent plaque progression. Serum interleukin-31 surge at subacute phase may play pathogenic role in cardiac allograft vasculopathy. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grants-in-Aid for Scientific Research (KAKENHI)

Spontaneous coronary artery dissection: insights from intravascular ultrasound

Abstract Introduction Spontaneous Coronary Artery Dissection (SCAD) may be at the origin of up to 25% of acute coronary events in women &amp;lt;50 yo with no or few risk factors. The diagnosis of SCAD is challenging and in some cases it may be ascertained only by intracoronary imaging such as intravascular ultrasound (IVUS) or optical coherence tomography (OCT). IVUS is widely available and has a better depth penetration compared to OCT, showing the extent of the false lumen and the aspect of the adventitia but its lower resolution does not always allow the visualization of smaller structures such as fenestrations. In a previous study we investigated the role of OCT in understanding the pathophysiology of SCAD and we reported a number of OCT complications. It is not known if these also apply to IVUS but since IVUS does not require additional contrast injection, the risk of false lumen (FL) propagation should be lower. Aim of the study To analyze the value of IVUS in the assessment of key features of SCAD and to explore the feasibility of three-dimensional (3D) reconstruction using IVUS imaging. Methods We collated the imaging findings of 15 cases of SCAD for which IVUS was used as part of routine clinical care. Images were assessed to determine the visualisation of the true lumen, the false lumen extent and its contents, the intima-media membrane, the presence of fenestrations, the external elastic lamina and underlying adventitia. Furthermore, we performed a 3D reconstruction of a type 2a dissection of the right coronary artery. The IVUS images were exported in DICOM format. The segmentation of the true and false lumens in the regions of interest was manually done using the ImageJ software. Subsequent images were processed using 3D Slicer and Paraview in order to obtain the 3D reconstruction of the dissected segment. Results The false lumen was entirely visible in 13/15 cases (87%) and the external elastic lamina in 12/15 cases (80%). In 3/15 cases (20%) the dissection was circumferential. The false lumen content had lower echogenicity compared to the surrounding tissue in all 15 cases. There was no visible fenestration. The 3D reconstruction (Figure 1) showed that the false lumen was larger than the true lumen. The general cross-sectional appearance was that of a “horseshoe” dissection but there was also a short segment of circumferential dissection and the intima-media membrane looked thickened. Conclusion Despite its resolution being lower than OCT, IVUS has a deep penetration and provides adequate imaging of the key features of SCAD. Perspectives We plan to further expand these findings in a larger series, intending to better characterize the false lumen and the adventitia in SCAD. IVUS findings in SCAD, 3D reconstruction Funding Acknowledgement Type of funding source: None

Intracoronary imaging reduces target vessel failure in primary percutaneous coronary intervention

Abstract Background Intracoronary imaging during percutaneous coronary intervention (PCI) allows better delineation of lesion characteristics and more accurate vessel sizing compared with angiogram alone. However, the benefit and safety of its use in primary percutaneous coronary intervention (PPCI) is uncertain. Purpose To determine whether the use of intracoronary imaging with intravascular ultrasound (IVUS) or optical coherence tomography (OCT)/ optical frequency domain imaging (OFDI) in PPCI is associated with better outcome. Method From Jan 2014 to Dec 2018, all patients with PPCI performed in our hospital were retrospectively studied. Baseline and procedural characteristics of angiographic-guided versus imaging-guided PCI were analyzed. Primary endpoint was target vessel failure, and procedural outcomes were contrast volume, number of stents implanted, mean stent length and diameter and use of post-dilatation. Safety outcomes were post-operative acute kidney injury (AKI), need for renal replacement therapy (RRT) and occurrence of no/slow reflow. Results A total of 408 patients were included, of which 223 (54.7%) used IVUS (n=176 80.3%) or OCT/OFDI (n=44 19.7%) during the procedure. Baseline and procedural characteristics were similar between both groups except more patients had history of PCI (12.6% vs 4.3% p=0.004) and left-main/ bifurcation lesions (12.6% vs 2.7% p&amp;lt;0.001). Intra-coronary imaging was associated with less target vessel failure during a median follow up of 22 months (Hazard ratio (HR): 0.59; 95% Confidence interval (CI): 0.36–0.97; p=0.036). Patients who had intra-coronary imaging during PPCI received more post-dilatation (77.1% vs 55.1% p&amp;lt;0.001), had longer (53mm vs 42mm p&amp;lt;0.001) and more stents (2 vs 1.67 p=0.003) implanted but had more contrast injected (151.2ml vs 130.6ml p=0.002). There was no statistically significant difference in mean stent diameter (3.07mm vs 3.02mm p=0.53), occurrence of slow/now reflow (15.3% vs 18.4% p=0.409), incidence of AKI (7.2% vs 10.8% p=0.197) or need for RRT (3.1% vs 5.4% p=0.254) between both groups. Conclusion Use of intra-vascular imaging during PPCI was associated with less target vessel failure, longer and more stents implanted and more frequent use of post-dilatation. Further prospective randomized controlled trial is suggested to confirm this benefit. Funding Acknowledgement Type of funding source: None

Macrophage accumulation within coronary arterial wall in diabetic patients with acute coronary syndrome: a study with in-vivo intravascular imaging modalities

Background and aimsMacrophage accumulation in arteriosclerotic plaque of coronary arteries is involved in plaque destabilization. Atherosclerosis has been known to be progressive in patients with type 2 diabetes mellitus (DM). This study compared the features of 3-dimensional (3D) spatial distribution of macrophage accumulation within coronary artery wall between acute coronary syndrome (ACS) patients with DM (n = 20) and those without (non-DM, n = 20) by using intravascular ultrasound (IVUS) and optical coherence tomography (OCT).MethodsThe OCT-derived macrophage accumulation was measured within the proximal left anterior-descending artery. This measurement was performed for the whole vessel segment of interest, higher shear stress region (flow divider side) and lower shear stress region (the opposite side).ResultsNormalized macrophage accumulation per unit length of the whole segment of interest was significantly larger in ACS patients with DM than without. In non-DM patients, macrophage density per IVUS-derived plaque volume was significantly higher in high shear stress region compared to low shear stress region, however, there was no significant difference between the two regions in DM patients. The macrophage density in the low shear stress region was significantly higher in the DM group than in the non-DM group. A multivariate analysis showed that the presence of DM was a major determinant for macrophage distribution.ConclusionsMacrophage accumulation was more abundant and homogeneous within coronary arterial wall in DM patients with ACS compared to non-DM patients, suggesting that plaque destabilization may occur more widely throughout coronary wall in DM patients.

A Brief History of Intracoronary Imaging

The purpose of this paper is to review the history of intracoronary imaging as it pertains to the development of intravascular ultrasound (IVUS) and optical coherence tomography (OCT) devices. Coronary angiography continues to maintain its stronghold as the diagnostic modality of choice in the diagnosis of coronary artery disease. Limitations in scope, however, have necessitated the development of adjunctive forms of imaging through IVUS and OCT in order to augment the comprehensive assessment and therapeutic management of angiographic findings. IVUS and OCT have significantly enhanced current day percutaneous coronary intervention. Over the last 30 years, advancements in their design and technology have solidified a framework for clinical decision-making in the cardiac catheterization lab and have helped more accurately assess and treat coronary artery disease.

Intravascular Imaging for Peripheral Vascular Disease and Endovascular Intervention

Intravascular imaging has been increasingly incorporated into endovascular practice. The goal of this review is to explore the contemporary technologies used to perform intravascular imaging as well as the evidence supporting their use in the diagnostic assessment and treatment of peripheral vascular disease. Although intravascular imaging has been more extensively studied in the coronary vasculature, there is a growing body of literature studying its use in other vascular territories. There are unique advantages and disadvantages for the two most commonly employed imaging modalities—intravascular ultrasound (IVUS) and optical coherence tomography (OCT). Either may enhance the diagnostic capabilities of conventional angiography depending upon the clinical situation. IVUS and OCT guidance for angioplasty and stent sizing in peripheral interventions has been shown to be safe, feasible and in many instances, effective. Studies suggest that clinically relevant outcomes such as vessel primary patency and long-term patency may be improved by utilizing these imaging technologies. While still employed as adjunctive modalities to angiography and peripheral intervention, IVUS or OCT may provide a potential pathway towards improving short- and long-term outcomes for a variety of vascular disease entities. At this time, further research is still warranted to better define the optimal role for these devices in non-coronary vascular beds.

Intracoronary Imaging for Assessment of Vascular Healing and Stent Follow-up in Bioresorbable Vascular Scaffolds.

Bioresorbable Vascular Scaffolds (BVS) are polymer-based materials implanted in the coronary arteries in order to treat atherosclerotic lesions, based on the concept that once the lesion has been treated, the material of the implanted stent will undergo a process of gradual resorption that will leave, in several years, the vessel wall smooth, free of any foreign material and with its vasomotion restored. However, after the first enthusiastic reports on the efficacy of BVSs, the recently published trials demonstrated disappointing results regarding long-term patency following BVS implantation, which were mainly attributed to technical deficiencies during the stenting procedure. Intracoronary imaging could play a crucial role for helping the operator to correctly implant a BVS into the coronary artery, as well as providing relevant information in the follow-up period. This review aims to summarize the role of intracoronary imaging in the follow-up of coronary stents, with a particular emphasis on the role of intravascular ultrasound and optical coherence tomography for procedural guidance during stent implantation and also for follow-up of bioabsorbable scaffolds.

5222A distinct LDL profile to predict the risk of cardiovascular disease in familial hypercholesterolemia subjects: initial pre-clinical results

Abstract Aim Cardiovascular disease development is highly variable between patients with familial hypercholesterolemia (FH). Since current risk prediction methods fail to estimate the risk of individual patients, all patients are treated with high-intensity lipid-lowering medication like statins and PCSK9-inhibitors. To prevent overtreatment (with its associated costs and side effects) of patients with a low risk, reliable biomarkers are urgently needed. While studying atherosclerosis development in an FH porcine model, we discovered a specific LDL profile that was directly associated with the severity of atherosclerosis development. Methods 10 adult pigs with an LDLR mutation received a high-fat diet for 12 months. Atherosclerosis development in the three main coronary arteries was monitored with intravascular ultrasound (IVUS) and optical coherence tomography at three time points. After sacrifice, tissue was harvested for detailed histological analysis of the coronary plaque composition. Size-exclusion chromatography (SEC, n=10) and LC-MSMS (n=4) were used to assess the plasma lipoprotein profile, and the sphingolipid content of LDL, relative to cholesterol. Results Imaging and histology revealed a marked difference in pigs that developed large, lumen intruding plaques (IVUS-based plaque burden 13–77%) within 9 months (n=5) and pigs (n=5) that only developed early lesions (IVUS-based plaque burden 8–34%), even after 12 months of follow-up. The plaques seen in the fast responding pigs possessed distinct characteristics of advanced disease (i.e. heavy macrophage infiltration, large lipid-rich necrotic cores, neovascularisation, micro- and macrocalcifications and intraplaque haemorrhage, see figure). In these fast responders, fibrous cap atheroma occupied 34% of the total artery. SEC revealed two distinct LDL subclasses: regular and “larger” LDL particles. Fast responding pigs with advanced atherosclerosis displayed a significantly higher ratio in cholesterol concentration of regular/'larger' LDL than slow responding pigs (1.7 (1.3–1.9) vs. 0.8 (0.6–1.2); (p=0.004), see figure). Compared to regular LDL, “larger” LDL contained relatively more sphingolipids in the fast responding than in the slow responding animals (regular LDL/'larger' LDL: S1P 0.5 (0.5–0.5) vs. 1.0 (0.8–1.2); Cer16:0 0.70 (0.67–0.73) vs. 1.04 (0.95–1.13); Cer18:0 0.60 (0.58–0.61) vs. 1.15 (1.13–1.16); Cer20:0 0.73 (0.73–0.74) vs. 0.94 (0.94–0.94)). “Larger” LDL particles and comparable sphingolipid ratios were also observed in FH patients. Cardiovascular data from our FH patient cohort, coupled to the LDL subclass distribution, will provide more insight into the potential of this novel biomarker. Conclusion A distinct difference in LDL subclasses, including a new “larger” LDL particle, was found in fast versus slow responding FH animals. This finding can potentially be used to identify FH patients at the highest risk of CVD to avoid overtreatement of low risk patients. Acknowledgement/Funding ERC- starter grant (grant agreement 310457)

P3558Cardiac magnetic resonance characteristics of the transplanted heart: first results of the prospective Heart-TIming CMR substudy

Abstract Background In case of heart transplantation (HTX) the heart is affected by several factors e.g. ischaemia/reperfusion, denervation, immunosuppression. During the adaptation, the heart may show marked temporal changes in terms of myocardial mechanics, function and tissue characteristics. To better understand temporal characteristics after orthotopic bicaval HTX we started the prospective Heart-TIming (Transplantation Imaging) trial in January 2018 including standard 12-lead ECG, 24-hour Holter monitor, endomyocardial biopsy, transthoracic echocardiography, invasive coronary angiography with intravascular ultrasound and optical coherence tomography and cardiac magnetic resonance (CMR). Aim In our CMR substudy we aimed to evaluate the physiological structural and functional left and right ventricular characteristics and their temporal changes after HTX using CMR. Methods As part of the study HTX patients underwent CMR at 1, 3 and 6 months after HTX (n=31; 52±10.5y, 25 male). Cine images, T2-weighted, late gadolinium enhancement (LGE) and adenosine stress perfusion (at 1 month) images were acquired. In order to describe physiological characteristics of the transplanted heart we excluded pts with significant coronary artery disease, ischaemic scar, ≥Grade II allograft rejection from this present study (n=6). We assessed the left (LV) and right ventricular (RV) ejection fractions, volumes, masses (M) and LV strain. We assessed the global strain values: longitudinal, circumferential (GCS) strain and the standard deviation (SD) of the peak longitudinal strain (LS) and the left ventricular mechanical dispersion. We compared baseline volumetric and strain parameters to age matched healthy controls (n=20; 47±11.4y, 15 male), and the temporal changes between one, three and 6 months. Results Comparing the HTX patients' CMR parameters at one month with normal controls, HTX patients had lower LV and RV end-diastolic volumes (LVEDVi: 76.6±15.9 vs 90.6±11.6ml/m2; RVEDVi 74.5±17.5 vs 90.3±12.1ml/m2, p&lt;0.05),stroke volumes (p&lt;0.05) and higher LVMi (67.6±14.4 vs 57.2±11g/m2, p&lt;0.05). CMR based strain analysis of the HTX pts showed hyperkinetic GCS (−40,5±6.3% vs −35.2±4.8%, p&lt;0.05), increased SD of peak LS and more pronounced mechanical dispersion (p&lt;0.001) compared to the controls. Examining temporal changes in HTX pts we found a decrease in LVMi (69.57±16.4 vs 61.7±9.8g/m2, p&lt;0.05) already at three months, normalization of GCS (−37.7±5.5% vs −32.6±4.9%, p&lt;0.05) and decrease in SD of peak LS (13.5±2.3 vs 11.4±2.4, p&lt;0.05) at 6 months. Oedema was present in all pts at one month after HTX, and disappeared after three months. LGE with aspecific pattern was present in 42%. LGE with aspecific pattern in HTX pts Conclusions Understanding the temporal changes of LV mechanics, function and tissue characteristics, furthermore the establishment of physiological values may help in the early, noninvasive identification of pathological changes in HTX pts. NCT number: NCT03499197 Acknowledgement/Funding Project no. NVKP_16-1-2016-0017 has been implemented with the support provided from the National Research, Development and Innovation Fund of Hungary

TCT-359 Intravascular Coronary Plaque Characterization Using Hybrid Intravascular Ultrasound and Optical Coherence Tomography: A Preliminary Study Based on User Interpretation Compared With Histology Reference

TCT-359 Intravascular Coronary Plaque Characterization Using Hybrid Intravascular Ultrasound and Optical Coherence Tomography: A Preliminary Study Based on User Interpretation Compared With Histology Reference

Mechanisms of Stent Failure: Lessons from IVUS and OCT

Despite significant advances in stent design and procedural technique, stent failure remains the “Achilles’ heel” of percutaneous coronary intervention (PCI). It is important to understand the mechanism of stent failure to prevent major adverse events and improve clinical outcomes. Two-dimensional angiography alone is insufficient for elucidating the etiology of stent failure. Intracoronary imaging modalities, including intravascular ultrasound (IVUS) and optical coherence tomography (OCT) have evolved to guide optimal stent placement during PCI, and have enabled identification of the etiology behind stent failure. In this review, we discuss the mechanisms of stent failure, use and limitations of intracoronary imaging (IVUS and OCT) to assess its etiology, and future directions for its use in patients undergoing coronary stent implantation.

Role of Intracoronary OCT in Diagnosis and Treatment of Acute Coronary Syndrome

Coronary angiography is the traditional standard imaging modality for visual evaluation of coronary anatomy and guidance of percutaneous coronary interventions (PCI). However, the 2-dimensional lumenogram cannot depict the arterial vessel per se and plaque characteristics, or directly assess the stenting result. Intracoronary imaging by means of intravascular ultrasound (IVUS) and optical coherence tomography (OCT) provides valuable incremental information that can be used clinically to optimize stent implantation and thereby minimize stent-related problems. Beyond guidance of stent selection and optimisation, imaging provides critical insights into the pathophysiology of acute coronary syndrome (ACS), greater clarity when confronted with angiographically ambiguous lesions and highlights the dynamic nature and significance of atherosclerotic coronary plaque. For several decades, most physicians have believed that ACS is caused by coronary thrombosis resulting from rupture of vulnerable plaque characterized by a thin fibrous cap overlying a large necrotic core and massive inflammatory cell infiltration. However, nearly one-third of ACS cases are caused by plaque erosion characterized by intact fibrous cap, less or absent necrotic core, less inflammation, and large lumen. Because of the limitations of current imaging modalities, including angiography and intravascular ultrasound, the importance of plaque erosion as a cause of acute coronary events is less well known. OCT as an emerging modality with extremely high resolution is the only intravascular imaging modality available for identification of plaque erosion in vivo, which provides new insight into the mechanism of ACS. More importantly, the introduction of OCT to clinical practice enables us to differentiate the patients with ACS caused by plaque erosion from those caused by plaque rupture, thereby providing precise and personalized therapy based on the different underlying mechanisms. This presentation will systematically review the morphological characteristics of plaque erosion identified by OCT and its implications for the management of ACS.