Intravascular Imaging Methods Research Articles

Potential of diagnostic electron microscopy of calcification, pathological neovascularization and elastolysis in combination with phenotyping of cell populations in large arteries

Aim. To determine the potential of diagnostic electron microscopy of intraplaque processes (severity of lipid damage, fibrous cap thickness and condition, severity of pathological neovascularization, presence, nature and severity of calcification, ratio and distribution of various cell populations).Material and methods. The study objects were plaques removed during endar­terectomy from the human carotid artery and segments of the human internal mammary artery removed during coronary bypass surgery. Whole specimens were subjected to chemical fixation, staining with heavy metal salts, embedding in epoxy resin followed by layer-by-layer grinding, polishing, contrasting, visualization using back-scattered electron scanning electron microscopy and three-dimensional reconstruction with color mapping (modified EM-BSEM).Results. The use of a modified EM-BSEM made it possible to: 1) visualize the fibrous cap thickness and assess the extracellular matrix; 2) analyze the neointimal lipid distribution; 3) perform three-dimensional reconstruction and analyze the microenvironment of calcifications of various sizes; 4) visualize endothelial cells, defects in interendothelial contacts and the basement membrane of neointimal capillaries with their subsequent three-dimensional reconstruction; 5) perform an analysis of age-dependent defects in the basement membrane and internal elastic membrane of the internal mammary artery. The resolution of the obtained images was significantly superior to intravascular imaging methods (intravascular ultrasound and optical coherence tomography), allowing additional assessment of capillary fluidity, the degree of calcification encapsulation and the condition of elastic fibers. Three-dimensional reconstruction of calcifications, neointimal capillaries and elastic fibers made it possible to assess their spatial density and heterogeneity. Simultaneously with the identification and assessment of these histological structures, objective phenotyping of cell populations was performed, which made it possible to isolate macrophages and foam cells, vascular smooth muscle cells, fibroblasts and endothelial cells in atherosclerotic plaques and automatically identify them through color mapping determined by their electronic contrast distribution signatures.Conclusion. The modified EM-BSEM method allows for universal electron microscopic diagnosis of atherosclerotic and elastolytic lesions of large arteries with high information content about vascular remodeling and high accuracy. Electronic contrast distribution signatures unique for each cell population indicate the possibility of their automated phenotyping using specialized neural network algorithms.

Вплив результатів внутрішньосудинного дослідження на безпосередній результат стентування основного стовбура лівої коронарної артерії

The purpose of the study is to optimize the immediate results of stenting of the main trunk of the left coronary artery (LCA) in patients with coronary heart disease (CHD) using intravascular imaging methods and modern technological approaches.Materials and methods. We present the experience of 186 consecutive patients with coronary artery disease in whom stenting of the Left Main (LM) coronary artery was performed.Results. Patients were divided into 2 groups – group I, «historical» (100 patients), where the intervention was performed without the use of intravascular imaging methods and proximal optimization methods (POT), and group II, which consisted of 86 patients in whom LM stenting was performed using intravascular imaging and modern methods of optimizing the stented segment. In general, groups I and II were comparable. About 20 % of patients had an isolated LM lesion. In other cases, according to the results of coronary angiography, multivessel lesions of the coronary vessels were recorded in the patients. The localization of the lesion was defined as ostial in 7.5 %, stem – 6.9 %, and distal with the involvement of LAD&CX in 85.6 %. Stenting with 1 stent was used in 132 patients (71 % of cases).Analyzing the final size of the stented LM segment in the groups, we noticed, that in group I, this figure was 3.41±0.41 mm, while in group II it was 3.97±0.61 mm (p<0.0001). In 3 patients of group I in 30 day period cardiac death were recorded, in the group II there were 2 (2.3 %) cases of LM dissection treated with additional stent implantation.In 3 patients (3 %) group I sudden cardiac death was registered in the 30-day period. In group II, there were 2 (2.3 %) cases of ossification, which were resolved by additional stent implantation.Conclusions. Intravascular imaging to assess the size and results of the intervention, as well as the use of the POT technique, significantly improves the positioning of the stent in the artery and provides a significantly larger diameter of the stented LM. Adequate optimization of the size of the stented LM can be obtained only with the help of intravascular imaging methods.

PATIENT WITH CHRONIC CORONARY SYNDROME: USE OF MULTIMODAL IMAGING FOR CORRECT DIAGNOSIS AND TREATMENT

Abstract In the context of CCS, CCTA allows us to discriminate with almost certainty between patients with the absence of disease. In case of a positive test, the characteristics of the plaque allow to stratified risk of developing future events. In doubtful cases it is necessary to resort to a multimodal imaging strategy for the correct diagnosis. We present the case of a 63-year-old hypertensive and dyslipidemic man who started presenting two months ago episodes of asthenia associated with tachycardia and jugular constriction after taking the usual CCB therapy. With a pre-test probability of 26%, a CCTA scan was requested which highlighted a non-calcific fibrous plaque (Image 1) at the level of the middle circumflex inducing a moderate stenosis (Cad-Rads 3). The patient underwent coronary angiography which confirmed this lesion and also highlighted a similar one downstream of the first. (Image 2) The OCT evaluation showed: 7 mm eccentric fibrous proximal plaque with evidence of multiple intimal layers (Healed plaque) in its distal third and with evidence of a medial-intimal flap involving three quadrants in the proximal two thirds (270°), with current intact endothelium and presence of neo-angiogenesis; MLA 2.33 mm² and AS 70%. Picture compatible with healed spontaneous dissection of the vessel. (Image 3) The subsequent 12 mm concentric plaque (360° involvement of the vessel) had a predominantly lipid component with macrophages and fibrous cap of 60 µm, MLA of 2.3mm² and AS 72%. Panel compatible with high risk plaque. (Image 4) It was decided to implant a 3.5x26mm drug-eluting stent through OCT-guided PCI with final MSA of 7.62 mm², stent expansion of 81%, absence of dissections at the edges and residual distal edge plaque with MLA of 7.6 mm². (Image 5). Conclusions Healed plaques are more frequent in patients with CCS and represent a plaque complicated by medial-intimal ulceration subsequently healed by neo-endothelialization. On CCTA they appear as non-calcific fibrous plaques with an intermediate density expressed in Hounsfield Units but the definitive diagnosis can only be obtained using an Intravascular Imaging method (OCT in the case presented). The patient appears asymptomatic after resuming his usual antihypertensive therapy at 30-day FU.

Intravascular ultrasound in children with congenital heart defects: a case series

Intravascular imaging methods are an actively developing area that was originally used in the treatment of coronary artery disease. With the help of intravascular ultrasound (IVUS), there is an opportunity to more objectively, in contrast to fluoroscopy, evaluate the vascular anatomy and lesion morphology, as well as optimize transcatheter interventions. In recent years, intravascular imaging has become widespread in the evaluation of children with congenital heart defects. A review of the literature on IVUS in endovascular treatment of congenital heart defects is presented and cases of the IVUS use in children with patent ductus arteriosus, descending aortic stenosis after interrupted aortic arch repair and pulmonary stenosis are presented.

Spontaneous coronary artery dissection in a young woman with signs of connective tissue dysplasia and hereditary thrombophilia: clinical case

BACKGROUND: Spontaneous coronary artery dissection (SCAD) is a disease that develops unrelated to intracoronary intervention, atherosclerosis, aortic dissection, or mechanical trauma and causes a false lumen (intramural hematoma) in the wall of the coronary artery (CA) with impaired blood flow in it and myocardial ischemia in the affected region of the CA. SCAD most often develops in young and middle-aged adults (aged ≤50 years); among women, it becomes the culprit in 24%–35% of cases of acute myocardial infarction (MI). SCAD is a risk factor for MI, and incorrect interpretation of the angiographic picture and intravascular imaging methods can lead to incorrect tactics of patient behavior.
 CLINICAL CASE DESCRIPTION: This article presents a clinical case of SCAD leading to the development of MI in a young woman with concomitant connective tissue dysplasia and hereditary thrombophilia. The angiographic disease course resembled focal atherosclerosis, and in the course of invasive management, complications had arisen, confirming the probable genesis of coronary artery obstruction.
 CONCLUSION: SCAD is a complex disease, with a sudden onset and an ambiguous prognosis. In most cases, SCAD develops in young women in the absence of cardiovascular factors. It is difficult to diagnose because its signs and symptoms are similar to more common diseases, mainly MI. SCAD can masquerade as focal stenosis on an angiogram, mimicking an atherosclerotic plaque. The «gold standard» for diagnosing SCAD is optical coherence tomography (OCT). OCT enables the visualization of the state of all coronary artery walls and elucidates the pathogenetic mechanisms of MI. If performing OCT is impossible after diagnostic coronary angiography in young patients in suspected cases, the likelihood of DST and SCAD risk must be assessed to avoid errors in choosing treatments. The technical accessibility of intracoronary imaging methods reduces the frequency of diagnostic and, consequently, treatment errors.

Endovascular treatment of lead-related superior vena cava syndrome after pacemaker implantation

Superior vena cava syndrome (SVCS) is due to impaired venous outflow from the head, neck, limbs and upper half of the body into the right atrium due to stenosis or complete obstruction of the superior vena cava (SVC). Increased venous pressure in the SVC and lack of timely treatment leads not only to serious complications, but also to death. In recent years, the etiology of SVCS has changed dramatically, mainly due to an increase in the number of implanted intravascular devices (central venous catheters, pacemakers, defibrillators, and other devices). Endovascular methods have become widely used in the treatment of patients with SVCS. This was primarily due to the minimally invasive nature of the intervention, the high technical success of the operation and the rapid onset of clinical improvement. Patients who develop SVCS after device implantation are predominantly younger and have a longer life expectancy. When choosing a treatment method, it is extremely important to take these factors into account and give preference to methods providing a long-term effect with the fewest possible complications. The article presents a case of endovascular treatment of a patient with SVCS occlusion, which developed 9 years after pacemaker implantation, using intravascular imaging methods.

Implications of Artificial Intelligence in Intravascular Imaging Methods

Implications of Artificial Intelligence in Intravascular Imaging Methods

Optimal time of dual antiplatelet therapy in patients with coronary heart disease (literature review)

However, the choice of optimal time of DAPT after PCI is still a difficult and urgent problem for the attending physician. An increase in DAPT duration after PCI correlates with a lower frequency of ischemic events. At the same time, with a longer DAPT regime, there is a more significant increase in the risks of postoperative bleeding. Hence, it is important to find a balance between the potential risks of bleeding and the expected benefits in reducing ischemic events, while taking into account the individual clinical characteristics of each patient. Intravascular imaging methods, such as intravascular coherence tomography, allow obtaining a highly informative lifetime morphological assessment of the coronary arteries, the formation of the neointima and the malposition of the implanted stent, which, in turn, can help in choosing the optimal timing of the DAPT and prevention of undesirable side events.

Intravascular imaging and physiological assessment of coronary blood flow for treatment strategy in patients with acute coronary syndrome. Analysis of Russian registry of intravascular imaging and physiological methods in 2021—2022

Intravascular imaging and physiological assessment of coronary blood flow for treatment strategy in patients with acute coronary syndrome. Analysis of Russian registry of intravascular imaging and physiological methods in 2021—2022

Capabilities of intravascular imaging techniques in the diagnosis of cardiac allograft vasculopathy: Literature review

Cardiac allograft vasculopathy (CAV) is a coronary heart disease (CHD), arising after an orthotopic heart transplant (OHT), and it is one of the leading causes of death in heart recipients. The probability of death is 10%. CAV can manifest as early as 1 year after OHT. Patients do not have pain syndrome that is typical for CHD due to cardiac denervation. The first clinical manifestations may be congestive heart failure, ventricular arrhythmias or even sudden cardiac death. Coronary angiography is the routine technique for CAV detection. However, it is not sensitive enough (about 44%) for CAV detection at an early stage of the disease. Today, intravascular imaging methods (intravascular ultrasound, optical coherence tomography), which allow the evaluation of the morphology of coronary artery lesions, including CAV, have become widespread. This article is devoted to the modern capabilities of intravascular imaging methods in the diagnosis of CAV. CAV is the main cause of myocardial infarction and chronic heart failure in patients after OHT. Intravascular imaging techniques allow early detection of this condition and prevention of unfavorable outcomes in a complex category of heart recipients. Given the advantages of optical coherence tomography (OCT) and disadvantages of intravascular ultrasound (IVUS), OCT appears to be a more informative method of CAV detection.

Intracoronary Imaging of Vulnerable Plaque-From Clinical Research to Everyday Practice.

The introduction into clinical practice of intravascular imaging, including intravascular ultrasound (IVUS), optical coherence tomography (OCT) and their derivatives, allowed for the in vivo assessment of coronary atherosclerosis in humans, including insights into plaque evolution and progression process. Intravascular ultrasound, the most commonly used intravascular modality in many countries, due to its low resolution cannot assess many features of vulnerable plaque such as lipid plaque or thin-cap fibroatheroma. Thus, novel methods were introduced to facilitate this problem including virtual histology intravascular ultrasound and later on near-infrared spectroscopy and OCT. Howbeit, none of the currently used modalities can assess all known characteristics of plaque vulnerability; hence, the idea of combining different intravascular imaging methods has emerged including NIRS-IVUS or OCT-IVUS imaging. All of those described methods may allow us to identify the most vulnerable plaques, which are prone to cause acute coronary syndrome, and thus they may allow us to introduce proper treatment before plaque destabilization.

High-frequency optical coherence tomography predictors of aneurysm occlusion following flow diverter treatment in a preclinical model

BackgroundHigh-frequency optical coherence tomography (HF-OCT) is an intravascular imaging method that allows for volumetric imaging of flow diverters in vivo.ObjectiveTo examine the hypothesis that a threshold for both volume and...

Long-term results of percutaneous coronary interventions in patients with diffuse and multivessel coronary artery diseases

Highlights. Two-year results of stenting in patients with diffuse and multivessel coronary artery lesions performed using intravascular research and control methods (optical coherence tomography, blood flow fractional reserve) are presented. A low incidence of myocardial infarction, repeated interventions and a high level of survival, free from significant cardiovascular complications, were noted when using intravascular research methods in patients during percutaneous coronary intervention in comparison with the patients who did not undergo intravascular methods.Aim. To evaluate the two-year results of percutaneous coronary interventions (PCI) in patients with diffuse and multivessel coronary lesions.Methods. 128 patients were included in the study and divided into two groups. In group I (n = 62) PCI was performed using intravascular imaging methods, in group II (n = 66) no intravascular imaging methods (retrospectively) were used. The measurement of fractional flow reserve (FFR) in diffusely altered arteries was performed against the background of maximum hyperemia between stenoses by pulling the sensor starting from the distal segment. Initially, the most distal hemodynamically significant stenosis underwent the stenting. Then, a repeated measurement of FFR was performed and it showed if the further stenting was needed. The results of stenting, as well as the determination of the stent implantation area were carried out by the method of optical coherence tomography.Results. 12 months after PCI the results of treatment were checked in all patients and after 24 months – in 106 patients (56 and 50, respectively, in groups I and II). The achievement of complete (functionally adequate, according to FFR measurements) myocardial revascularization was achieved in 93.5% of patients from group I, while the result in the control group was only 56% of patients. The average number of stenoses in the target non-occluded artery according to angiography and after FFR measurement was the following: in patients with two-vessel lesions – 2.95±0.65 and 1.82±0.88, respectively, and in patients with three-vessel lesions – 2.96±0.6 and 2.24±0.76, respectively (p = 0.0024). After 12 months of follow-up, significant differences were observed between groups I and II in the frequency of myocardial infarction (1.8 and 4.0%, respectively; χ2 = 5.172) and repeated interventions (3.6 and 16.0%, respectively; χ2 = 8.114). By the 24th month of follow-up, among the observed patients, the total frequency of myocardial infarction, repeated interventions and cardiac death were significantly higher in patients of group II compared with group I and they were 45.5 and 9.6%, respectively (χ2 = 14.784; p<0,0001).Conclusion. Long-term results of PCI in patients with diffuse and multivessel coronary lesions using intravascular imaging methods (optical coherence tomography and FFR measurements) are characterized by low cardiac complications, compared with patients operated without imaging methods.

The role of intravascular methods of examination of coronary arteries in the selection of patients with diffuse and multivessel lesions for myocardial revascularization

Objective Assessment of the role of intravascular imaging methods in choosing the surgical strategy of myocardial revascularization.Material and Methods The study included 62 patients with diffuse and multivessel coronary artery disease, who underwent percutaneous coronary infervention (PCI) using intravascular imaging methods. Measurement of fractional flow reserve (FFR) in diffusely altered arteries was performed under conditions of maximum hyperemia, sequentially between stenoses, using the sensor, starting from the distal segment. Initially, the most distal hemodynamically significant stenosis was stented. Then, a repeated measurement of FFR was performed, and the issue of the need for stenting of other stenoses was solved. The results of stenting, as well as determination of the area of stent implantation were carried out by the method of optical coherence tomography (OCT).Results After FFR measurement the number of arteries with hemodynamically significant stenoses decreased by 24.7% (from 93 to 70). It was also noted that in patients with two-vessel lesions, the average number of such stenoses decreased from 2.95 ± 0.65 to 1.82 ± 0.88, and in patients with three-vessel lesions – from 2.96 ± 0.6 to 2.24 ± 0.76 respectively (p = 0.0024). Complete (functionally adequate according to FFR measurements) myocardial revascularization was achieved in 88.7% of patients. The second-generation drug eluting stents were implanted in 82 (47.1%) patients, and the third generation stents – in 92 (52.9%) patients. At the same time, the success rate of recanalization of occlusions was 100%. Overall, optimal stent implantation was achieved in all patients. Major cardiovascular complications were observed in 1 (1.6%) patient, which required additional interventions.Conclusion Complex use of intravascular imaging methods (OCT and FFR measurements) allows a differentiated approach to the assessment of each stenosis of the affected artery in patients with diffuse and multivessel coronary lesions, to achieve a high frequency of complete myocardial revascularization, as well as to reduce the number of unnecessary interventions and intraoperative complications.

Accuracy of optical coherence tomography imaging in assessing aneurysmal remnants after flow diversion

BackgroundOptical coherence tomography (OCT) is an ultra-high resolution real-time intravascular imaging method that is gaining interest in cerebrovascular applications.ObjectiveTo compare, in a rabbit elastase aneurysm model, digital subtraction angiography (DSA)...

Intravascular imaging of atherosclerotic plaques in patients with cardiorenal syndrome: potential use of optical coherence tomography

Currently, kidney transplantation and hemodialysis are the primary therapies for end-stage renal disease. High mortality, mostly caused by cardiovascular disease, remains the main challenge in the treatment of this category of patients. It has been shown that in patients with end-stage chronic kidney disease undergoing hemodialysis, the risk of mortality due to cardiovascular disease is up to 20 times higher than in the sex- and age-matched general population. The indicated data determined the appropriateness of isolating cardiorenal relationships into a single cardiorenal syndrome (CRS). Due to the facts mentioned above, intravascular imaging methods, notably optical coherence tomography (OCT), are particularly important in diagnosing coronary artery lesions. This review analyses the data published to date on the features and capabilities of OCT in CRS patients.

The randomized study of preventive revascularization of vulnerable coronary artery plaques in patients with stable coronary artery disease

Background. Today, a number of unresolved issues remain regarding vulnerable coronary plaques, one of which is the need for preventive revascularization.Aim. Evaluation of the appropriateness of preventive revascularization of functionally insignificant lesions of the coronary arteries with signs of vulnerability according to the virtual histology of intravascular ultrasound in patients with stable coronary artery disease.Methods. The prospective randomized study includes patients with stable coronary artery disease and isolated intermediate-grade coronary stenosis. The first step in patients is measured fractional flow reserve to confirm the hemodynamic insignificance of stenosis. Then an intravascular ultrasound is performed to verify signs of plaque vulnerability: a thin-cap fibroatheroma and / or minimum lumen area <4 mm2 and/or plaque burden >70%. After that, patients are randomized into two groups: preventive revascularization or optimal medical therapy. After 12 months, patients undergo repeated intravascular ultrasound and end-point analysis.Results. So far, 10 patients have been included in the study (6 in the preventive revascularization group and 4 in the optimal medical therapy group). No endpoints and complications were recorded in both groups in 30-days follow-up.Conclusion. Intravascular imaging methods can identify vulnerable coronary plaques, which allows you to use a personalized approach in determining treatment tactics, one of which can be preventive revascularization.

A modern view on revascularisation of brain and myocardium in patients with multifocal atherosclerosis: A review

Among cardiovascular diseases, multifocal atherosclerosis has begun occurring more frequently in the recent years; its manifestations such as coronary heart disease and acute cerebrovascular disease are the primary cause of death and disability worldwide. Both open and endovascular methods of surgical revascularisation of the brain and myocardium are presently used for addressing this global epidemic. Therefore, the outcomes and disease course during both the early postoperative and long-term periods in patients with multifocal atherosclerosis depend on the choice of appropriate surgical strategies. However, there is no consensus on the optimal strategies for the combined treatment of lesions in the coronary and cerebral basins. Consequently, there are no clinical recommendations or randomised trials that provide recommendations on the choice of treatment approaches in this cohort of patients. The specific treatment options are based on the personal experience of the clinic and the decision of the multidisciplinary team.Nevertheless, it is certain that carotid endarterectomy remains the gold standard for the treatment of significant stenosis of internal carotid artery, including that with complex anatomical characteristics and severe calcification; carotid endarterectomy is also the most important preventative measure for the acute violation of cerebral circulation. In addition, given the emergence of new coronary stents and the spread of intravascular imaging methods, percutaneous coronary intervention is increasing its evidence base by the year by demonstrating efficacy even in patients with concomitant left coronary artery trunk and multi-vascular coronary bed lesions.The use of carotid endarterectomy in combination with percutaneous coronary intervention in patients with lesions in both vascular basins for achieving hybrid revascularisation is promising although studied minimally.Therefore, in the present review, we aimed to present the current understanding of the methods utilised for revascularisation of the brain and myocardium as well as the hybrid revascularisation approach for the treatment of patients with multifocal atherosclerosis, with consideration given to its advantages and prospects.Received 12 April 2019. Revised 17 December 2019. Accepted 24 December 2019.Funding: The study did not have sponsorship.Conflict of interest: Authors declare no conflict of interest.

The use of optical coherence tomography imaging of the vascular wall of the coronary arteries before and after stenting

Introduction. Optical coherence tomography (OCT) is an intravascular imaging method that allows to evaluate the structure of the vascular wall, as well as to monitor the process of stent installation and healing.The aim of this work was to identify factors affecting neointimal vascular healing after implantation of drug­eluting stents.Material and methods. In 35 patients with acute coronary syndrome without ST elevation, everolimus­eluted stents with permanent and biodegradable polymer were installed. After 6 months patients underwent control coronary angiography with OCT, the state of neointima of previously implanted stents was analyzed. Clinical, anamnestic and laboratory parameters were evaluated.Results. 28750 struts of stents were analyzed and the healing score was calculated. The healing score depended on the patient’s age (r=0.60710, p=0.0003), a history of diabetes mellitus (p=0.0477), current myocardial infarction (p=0.0183), and the degree of coronary artery disease (p=0.0355). The healing score was signifcantly lower in patients with a Syntax score <22 (p=0.004).Conclusion. The results of the research showed that main factors that impair neointimal healing are age, the presence of diabetes, the characteristics of the lesion of the coronary arteries; they may affect the duration of dual antiplatelet therapy.

Intravascular Photothermal Strain Imaging for Lipid Detection.

Cardiovascular disease (CVD) is one of the major threats to humanity, accounting for one-third of the world’s deaths. For patients with high-risk CVD, plaque rupture can lead to critical condition. It is therefore important to determine the stability of the plaque and classify the patient’s risk level. Lipid content is an important determinant of plaque stability. However, conventional intravascular imaging methods have limitations in finding lipids. Therefore, new intravascular imaging techniques for plaque risk assessment are urgently needed. In this study, a novel photothermal strain imaging (pTSI) was applied to an intravascular imaging system for detecting lipids in plaques. As a combination of thermal strain imaging and laser-induced heating, pTSI differentiates lipids from other tissues based on changes in ultrasound (US) velocity with temperature change. We designed an optical pathway to an intravascular ultrasound catheter to deliver 1210-nm laser and US simultaneously. To establish the feasibility of the intravascular pTSI system, we experimented with a tissue-mimicking phantom made of fat and gelatin. Due to the difference in the strain during laser heating, we can clearly distinguish fat and gelatin in the phantom. The result demonstrates that pTSI could be used with conventional intravascular imaging methods to detect the plaque lipid.