Intravascular Ultrasound Imaging Research Articles

Prevention of neointimal hyperplasia induced by an endovascular stent via intravenous infusion of mesenchymal stem cells.

In-stent restenosis after percutaneous transluminal angioplasty and stenting (PTAS) due to neointimal hyperplasia is a potential cause of clinical complications, including repeated revascularization and ischemic events. Neointimal hyperplasia induced by an inflammatory response to the stent strut may be a possible mechanism of in-stent restenosis. Intravenous infusion of bone marrow-derived mesenchymal stem cells (MSCs) has been reported to show therapeutic efficacy for cerebral stroke, presumably by an antiinflammatory effect. This study aimed to determine whether MSCs can reduce or prevent neointimal hyperplasia induced by an endovascular stent. In this study, two types of bare metal stents were deployed using a porcine (mini-pig) model. One stent was implanted in the common carotid artery (CCA), which is considered quite similar to the human CCA, and the other was inserted in the superficial cervical artery (SCA), which is similar in size to the human middle cerebral artery. Angiographic images, intravascular ultrasound (IVUS) imaging, and microscopic images were used for analysis. Angiographic images and IVUS studies revealed that intravenous infusion of MSCs immediately after deployment of stents prevented in-stent stenosis of the CCA and SCA. Histological analysis also confirmed that inflammatory responses around the stent struts were reduced in both the stented CCA and SCA in the mini-pig. Intravenous infusion of MSCs inhibited the inflammatory reaction to an implanted stent strut, and prevented progressive neointimal hyperplasia in the stented CCA and SCA in a porcine model. Thus, MSC treatment could attenuate the recurrence of cerebral ischemic events after stenting.

Catheter-mounted dual-frequency ultrasound transducers for intravascular contrast-enhanced superharmonic imaging

Vulnerable atherosclerotic plaques are a source of morbidity and mortality and are hypothesized to be correlated with abnormal development of microvasculature in arterial walls. Thus, there is an interest in assessing microvascularity for the plaque diagnosis. However, conventional catheter-delivered, high-frequency (>20 MHz) intravascular ultrasound imaging is unable to resolve vasa vasorum microvessels. We present here the development of a custom dual-frequency transducer-tipped catheter for contrast-enhanced superharmonic imaging of plaque-associated microvasculature. We exploit our previous design of the miniaturized dual-element, stacked-type needle transducer. A 4/22 MHz dual-frequency transducer with a lateral dimension of 800 μm is assembled with a 70 cm-long drive shaft inside a 4 Fr-catheter. We designed a 4 MHz-transmitter element to generate moderate amplitude (>1 MPa peak-negative-pressure) pulses for bubble excitation. A confocally aligned 22 MHz-receiver element is designed to detect contrast generated superharmonics (>10 MHz) with substantial tissue rejection. We tested the catheter in a tissue-mimicking phantom simulating an arterial lumen with surrounding microvasculature. The in vitro imaging data were acquired through a rotational pull-back (2 mm) imaging procedure with microbubble infusion. The resulting superharmonic images display a clearly defined microvessel with an approximated contrast-to-tissue ratio of 12 dB and an axial resolution of 300 μm.Vulnerable atherosclerotic plaques are a source of morbidity and mortality and are hypothesized to be correlated with abnormal development of microvasculature in arterial walls. Thus, there is an interest in assessing microvascularity for the plaque diagnosis. However, conventional catheter-delivered, high-frequency (>20 MHz) intravascular ultrasound imaging is unable to resolve vasa vasorum microvessels. We present here the development of a custom dual-frequency transducer-tipped catheter for contrast-enhanced superharmonic imaging of plaque-associated microvasculature. We exploit our previous design of the miniaturized dual-element, stacked-type needle transducer. A 4/22 MHz dual-frequency transducer with a lateral dimension of 800 μm is assembled with a 70 cm-long drive shaft inside a 4 Fr-catheter. We designed a 4 MHz-transmitter element to generate moderate amplitude (>1 MPa peak-negative-pressure) pulses for bubble excitation. A confocally aligned 22 MHz-receiver element is designed to detect contra...

P3588The synergistic effect of NIRS-detected lipid-rich plaque and 5 different multidirectional wall shear stress metrics on human coronary plaque growth

Abstract Introduction Local wall shear stress (WSS) metrics, high local lipid levels (as detected by near-infrared spectroscopy (NIRS)), as well as systemic lipid levels, have been individually associated with atherosclerotic disease progression. However, a possible synergistic effect remains to be elucidated. This study is the first study to combine WSS metrics with NIRS-detected local lipid content to investigate a potential synergistic effect on plaque progression in human coronary arteries. Methods The IMPACT study is a prospective, single centre study investigating the relation between atherosclerotic plaque progression and WSS in human coronary arteries. Patients with ACS treated with PCI were included. At baseline and after 1-year follow-up, patients underwent near-infrared spectroscopy intravascular ultrasound (NIRS-IVUS) imaging and intravascular doppler flow measurements of at least one non-culprit coronary artery. After one month, a CT angiography was made. CT derived centreline combined with IVUS lumen contours resulted in a 3D reconstruction of the vessel. The following WSS metrics were computed using computational fluid dynamics applying the vessel specific invasive flow measurements: time-average wall shear stress (TAWSS), relative residence time (RRT), cross-flow index, oscillatory shear index and transverse wall shear stress. Low TAWSS is known as pro atherogenic, in contrast to all the other shear stress metrics, at which a high magnitude is pro-atherogenic. The arteries were divided into 1.5mm/45° sectors. Based on NIRS-IVUS, wall thickness change over time was determined and NIRS positive sectors detected. Furthermore, per vessel the shear stress was divided into tertiles (low, intermediate, high). To investigate the synergistic effect of local lipids on shear stress related plaque growth, wall thickness change over time was related to the different shear stress metrics comparing the NIRS-positive with the NIRS-negative sectors. Results 15 non-culprit coronary arteries from the first 14 patients were analyzed (age 62±10 years old and 92.9% male). A total of 2219 sectors were studied (5.2%, N=130, NIRS-positive) for wall thickness changes. After studying all five shear stress metrics, we found for TAWSS and RRT that presence of lipids, as detected by NIRS, amplified the effect of shear stress on plaque progression (see figure). Sectors presenting with lipid-rich plaque, compared to NIRS-negative sectors, showed more progression when they were exposed to low TAWSS (p=0.07) or high RRT (p=0.012) and more regression in sectors exposed to high TAWSS (p=0.10) or low RRT (p=0.06). Delta wall thickness vs shear stress Conclusion We presented the first preliminary results of the IMPACT study, showing the synergistic effect of lipid rich plaque and shear stress on plaque progression. Therefore, intravascular lipid-rich plaque (NIRS) assessment has added value to shear stress profiling for the prediction of plaque growth, leading to improved risk stratification. Acknowledgement/Funding ERC starting grant 310457

3047Long-term changes after carotid stenting assessed by intravascular ultrasound and near-infrared spectroscopy

Abstract Background/Introduction Long-term effect of carotid stenting (CAS) on the stabilization of the plaque is not well described. The interaction among the late stent expansion, neointimal hyperplasia, and lipid core might explain stabilization of the plaque and low long-term incidence of stroke after CAS. Purpose To assess long-term change in the lipid signal, stent, and luminal dimensions and restenosis after CAS with the multimodality intravascular ultrasound (IVUS) and near-infrared spectroscopy (NIRS) imaging. Methods We performed follow-up NIRS-IVUS imaging in patients who underwent CAS at our institution. Of the 112 patients (120 carotid arteries) who had NIRS-IVUS during CAS, 96 were alive at the time of the study, and 52 (58 carotid arteries) agreed to participate on the study. The lipid signal of the stented segment was calculated from the NIRS-derived chemogram (a spectroscopic map) as the lipid core burden index (LCBI, a dimensionless number from 0 to 1000). Volumetric calculations were performed using dedicated software with the automated lumen and stent detection and manual corrections. Median time from CAS to the follow-up examination was 31 months (range 5–56). Results The mean (± SD) LCBI significantly decreased from 32±56 to 17±27 (p=0,002). The mean stent volume significantly increased from 717±302 mm3 to 1019±429 mm3 (p<0,001) with mean stent expansion 43±24%. The mean luminal volume increased from 717±302 mm3 to 760±359 mm3 (p=0,025) due to the mean in-stent restenosis (ISR) 26±15% of the stent volume. Significant increase in the mean minimal stent area (MSA) (from 11,1±3,0 mm2 to 15,0±3,5 mm2, p<0,001) was not observed in the minimal luminal area (MLA) (from 11,1±3,0 mm2 to 11,4±4,4 mm2, p=0,098) due to the ISR. Significant restenosis (reduction of MLA ≥50% from baseline) was present in 7 stents. Conclusions During nearly three years of the follow-up after CAS the lipid signal decreased suggesting stabilization of the plaque. Significant late stent expansion was balanced with substantial neointimal hyperplasia therefore the late luminal gain was only modest in volume and nonsignificant at the site of MLA. There was a major variability in the rate of the late stent expansion and restenosis.

The efficacy of glycemic control with continuous glucose monitoring on atheroma progression: rationale and design of the Observation of Coronary Atheroma Progression under Continuous Glucose Monitoring Guidance in Patients with Type 2 Diabetes Mellitus (OPTIMAL).

Patients with type 2 diabetes mellitus (T2DM) are high-risk subjects who more frequently have micro- and macrovascular diseases including coronary artery disease (CAD). Since impaired glycemic homeostasis directly influences the formation and propagation of atherosclerotic plaques, optimal management of glycemic status is required for the prevention of diabetic atherosclerosis. Continuous glucose monitoring (CGM) provides not only average glucose level but also the degree of glucose fluctuation and hypoglycemia. Given the association of glycemic variability with diabetic macrovascular diseases, CGM-based glycemic management could favorably modulate glycemic fluctuation, thereby potentially modifying atheroma burden in T2DM subjects. To test this hypothesis, the Observation of Coronary Atheroma Progression under Continuous Glucose Monitoring Guidance in Patients with Type 2 Diabetes Mellitus (OPTIMAL) study has been designed (Japan Registry of Clinical Trials: jRCT1052180152, University Hospital Medical Information Network Clinical Trial Registry UMIN000036721). The OPTIMAL is a single-center, randomized trial to evaluate the efficacy of CGM-based glycemic control on atheroma progression in T2DM patients with CAD by using serial intravascular ultrasound (IVUS) and near-infrared spectroscopy (NIRS) imaging. A total of 90 eligible subjects will be randomized 1:1 into two groups to receive either CGM-based glycemic control or HbA1c-baded glycemic management. Coronary angiography and NIRS/IVUS imaging is repeated at the end of the assigned treatment period. The primary endpoint is the normalized absolute change in total atheroma volume (TAV) from baseline to 12 months. The secondary endpoints include (I) the absolute change in percent atheroma volume, (II) the percent change in lipid core burden index, (III) the change in coefficient variance measured by CGM, (IV) the change in atherogenic markers (high-density lipoprotein functionality, proprotein convertase subxilisin/kexin type 9 and fatty-acid binding proteins), and (V) the frequency of hypoglycemia. Safety will also be evaluated. The collaboration of CGM use with serial NIRS/IVUS imaging will enable to compare atheroma progression rate under CGM-based glycemic management and HbA1c-based approach.

Plaque Layer Identification in IVUS Images by Iterative based Energy Minimization of Contour Method (IEMCM)

Atherosclerotic plaque is the major cause of coronary heart artery diseases. Heart artery plaque layer analysis is one of the most important and challenging problem, which can be determined by using Intravascular Ultrasound (IVUS) Cross Sectional images, which is an excellent ultrasound study system for extracting and to easily identify the plaque layer by using the shape parameter measurements. This paper presents and elucidates the novel approach to find out the plaque layer with the help of the artery cross sectional layers determination, which are adventitia, media, intima and lumen layers. This system measures the layer’s performance to make the clear way to identify the plaque layer, which proposes a new method namely Iterative based Energy Minimization of Contour method (IEMCM). The cross sectional IVUS acts as an input image for processing and analysis of the plaque layer based on the IVUS Simulation study Measurements of coronary vessel wall dimensions and shape measurements. The proposed method produced high accuracy when compared to the existing methods.

Clinical expert consensus document on standards for measurements and assessment of intravascular ultrasound from the Japanese Association of Cardiovascular Intervention and Therapeutics.

Intravascular ultrasound (IVUS) provides precise anatomic information in coronary arteries including quantitative measurements and morphological assessment. To standardize the IVUS analysis in the current era, this expert consensus document summarizes the methods of measurements and assessment of IVUS images.

Identification of patients and plaques vulnerable to future coronary events with near-infrared spectroscopy intravascular ultrasound imaging: a prospective, cohort study

Near-infrared spectroscopy (NIRS) intravascular ultrasound imaging can detect lipid-rich plaques (LRPs). LRPs are associated with acute coronary syndromes or myocardial infarction, which can result in revascularisation or cardiac death. In this study, we aimed to establish the relationship between LRPs detected by NIRS-intravascular ultrasound imaging at unstented sites and subsequent coronary events from new culprit lesions. In this prospective, cohort study (LRP), patients from 44 medical centres were enrolled in Italy, Latvia, Netherlands, Slovakia, UK, and the USA. Patients with suspected coronary artery disease who underwent cardiac catheterisation with possible ad hoc percutaneous coronary intervention were eligible to be enrolled. Enrolled patients underwent scanning of non-culprit segments using NIRS-intravascular ultrasound imaging. The study had two hierarchal primary hypotheses, patient and plaque, each testing the association between maximum 4 mm Lipid Core Burden Index (maxLCBI4mm) and non-culprit major adverse cardiovascular events (NC-MACE). Enrolled patients with large LRPs (≥250 maxLCBI4mm) and a randomly selected half of patients with small LRPs (<250 maxLCBI4mm) were followed up for 24 months. This study is registered with ClinicalTrials.gov, NCT02033694. Between Feb 21, 2014, and March 30, 2016, 1563 patients were enrolled. NIRS-intravascular ultrasound device-related events were seen in six (0·4%) patients. 1271 patients (mean age 64 years, SD 10, 883 [69%] men, 388 [31%]women) with analysable maxLCBI4mm were allocated to follow-up. The 2-year cumulative incidence of NC-MACE was 9% (n=103). Both hierarchical primary hypotheses were met. On a patient level, the unadjusted hazard ratio (HR) for NC-MACE was 1·21 (95% CI 1·09-1·35; p=0·0004) for each 100-unit increase maxLCBI4mm) and adjusted HR 1·18 (1·05-1·32; p=0·0043). In patients with a maxLCBI4mm more than 400, the unadjusted HR for NC-MACE was 2·18 (1·48-3·22; p<0·0001) and adjusted HR was 1·89 (1·26-2·83; p=0·0021). At the plaque level, the unadjusted HR was 1·45 (1·30-1·60; p<0·0001) for each 100-unit increase in maxLCBI4mm. For segments with a maxLCBI4mm more than 400, the unadjusted HR for NC-MACE was 4·22 (2·39-7·45; p<0·0001) and adjusted HR was 3·39 (1·85-6·20; p<0·0001). NIRS imaging of non-obstructive territories in patients undergoing cardiac catheterisation and possible percutaneous coronary intervention was safe and can aid in identifying patients and segments at higher risk for subsequent NC-MACE. NIRS-intravascular ultrasound imaging adds to the armamentarium as the first diagnostic tool able to detect vulnerable patients and plaques in clinical practice. Infraredx.

Patient specific characterization of artery and plaque material properties in peripheral artery disease

Patient-specific finite element (FE) modeling of atherosclerotic plaque is challenging, as there is limited information available clinically to characterize plaque components. This study proposes that for the limited data available in vivo, material properties of plaque and artery can be identified using inverse FE analysis and either a simple neo-Hookean constitutive model or assuming linear elasticity provides sufficient accuracy to capture the changes in vessel deformation, which is the available clinical metric. To test this, 10 human cadaveric femoral arteries were each pressurized ex vivo at 6 pressure levels, while intravascular ultrasound (IVUS) and virtual histology (VH) imaging were performed during controlled pull-back to determine vessel geometry and plaque structure. The VH images were then utilized to construct FE models with heterogeneous material properties corresponding to the vessel plaque components. The constitutive models were then fit to each plaque component by minimizing the difference between the experimental and the simulated geometry using the inverse FE method. Additionally, we further simplified the analysis by assuming the vessel wall had a homogeneous structure, i.e. lumping artery and plaque as one tissue. We found that for the heterogeneous wall structure, the simulated and experimental vessel geometries compared well when the fitted neo-Hookean parameters or elastic modulus, in the case of linear elasticity, were utilized. Furthermore, taking the median of these fitted parameters then inputting these as plaque component mechanical properties in the finite element simulation yielded differences between simulated and experimental geometries that were on average around 2% greater (1.30–5.55% error range to 2.33–11.71% error range). For the homogeneous wall structure the simulated and experimental wall geometries had an average difference of around 4% although when the difference was calculated using the median fitted value this difference was larger than for the heterogeneous fits. Finally, comparison to uniaxial tension data and to literature constitutive models also gave confidence to the suitability of this simplified approach for patient-specific arterial simulation based on data that may be acquired in the clinic.

TCT-659 Intravascular Ultrasound Analysis of Calcified Neoatherosclerosis Causing In-Stent Restenosis and Its Clinical Implication: From IRIS DES and DEB Registry

The prevalence and clinical features of calcified neoatherosclerosis (CNA) of coronary in-stent restenosis (ISR) are not well known. Patients who underwent percutaneous coronary intervention for ISR lesions with pre- and post-procedural intravascular ultrasound (IVUS) image were evaluated from IRIS

Segmentation of Media and Lumen in Intravascular Ultrasound Image Using Guided Multiscale Normalized Cut

Segmentation of Media and Lumen in Intravascular Ultrasound Image Using Guided Multiscale Normalized Cut

Interference-free Detection of Lipid-laden Atherosclerotic Plaques by 3D Co-registration of Frequency-Domain Differential Photoacoustic and Ultrasound Radar Imaging

As lipid composition of atherosclerotic plaques is considered to be one of the primary indicators for plaque vulnerability, a diagnostic modality that can sensitively evaluate their necrotic core is highly desirable in atherosclerosis imaging. In this regard, intravascular photoacoustic (IVPA) imaging is an emerging plaque detection modality that provides lipid-specific chemical information of arterial walls. Within the near-infrared window, a 1210-nm optical source is usually chosen for IVPA applications because lipid exhibits a strong absorption peak at that wavelength. However, other arterial tissues also show some degree of absorption near 1210 nm and generate undesirable interfering PA signals. In this study, a novel wavelength-modulated Intravascular Differential Photoacoustic Radar (IV-DPAR) modality was introduced as an interference-free detection technique for a more accurate and reliable diagnosis of plaque progression. By using two low-power continuous-wave laser diodes in a differential manner, IV-DPAR could efficiently suppress undesirable absorptions and system noise, while dramatically improving system sensitivity and specificity to cholesterol, the primary ingredient of plaque necrotic core. When co-registered with intravascular ultrasound imaging, IV-DPAR could sensitively locate and characterize the lipid contents of plaques in human atherosclerotic arteries, regardless of their size and depth.

Intravascular Ultrasound (IVUS) Imaging During Transvenous Lead Extraction

Intravascular Ultrasound (IVUS) Imaging During Transvenous Lead Extraction

A Post-market, Multi-vessel Evaluation of the Imaging of Peripheral Arteries for Diagnostic Purposes Comparing Optical Coherence Tomography and Intravascular Ultrasound Imaging (SCAN)

A Post-market, Multi-vessel Evaluation of the Imaging of Peripheral Arteries for Diagnostic Purposes Comparing Optical Coherence Tomography and Intravascular Ultrasound Imaging (SCAN). To compare the diagnostic performance of Intravascular Ultrasound (IVUS) and Optical Coherence Tomography (OCT) imaging in the matched segments of peripheral vessels in patients with suspected peripheral vascular disease.

Shrinkage as a potential mechanism of recurrent clinical events in patients with a large vulnerable plaque.

This study aimed to investigate the progression and vascular shrinkage of vulnerable plaque lesions with a plaque burden at least 70% among patients with coronary artery disease by optical coherence tomography (OCT) and intravascular ultrasound (IVUS). Fifty-six OCT-identified vulnerable plaques from 47 patients were included among coronary angiography-identified nonculprit/nontarget lesions. Serial IVUS images were used to assess plaque progression and vascular shrinkage. Thirty-five small vulnerable plaques (plaque burden <70%, group A) and 21 large vulnerable plaques (plaque burden ≥70%, group B) were identified. The IVUS results at baseline show that mean plaque areas (P < 0.001) and the percentage atheroma volume (PAV) (P < 0.0001) were greater and the minimal lumen area (P < 0.0001) was smaller in group B. The absolute and relative changes in the PAV and mean plaque area from baseline to follow-up were not significantly different. However, the lesions exhibited vessel shrinkage [the mean external elastic membrane (EEM) area (P = 0.02) and mean lumen area (P = 0.03) were significantly smaller in group B] from baseline to follow-up. Patients in group B also exhibited clinical events (recurrent angina symptoms) during the follow-up period. Positive correlations were found between changes in the mean plaque area and the mean EEM area in large vulnerable plaques (r = 0.61, P < 0.0001) and between changes in the mean EEM area and the mean lumen area in large vulnerable plaques (r = 0.61, P < 0.0001). Vulnerable plaque progression was not different between small and large vulnerable plaques. However, large vulnerable plaque lesions tended to exhibit vascular shrinkage, which is possible a cause of coronary artery lumen loss in patients with large vulnerable plaques.

Plaque burden can be assessed using intravascular optical coherence tomography and a dedicated automated processing algorithm: a comparison study with intravascular ultrasound.

Plaque burden (PB) measurement using intravascular optical coherence tomography (IVOCT) is currently thought to be inferior to intravascular ultrasound (IVUS). We developed an automated IVOCT image processing algorithm to enhance the external elastic lamina (EEL) contour. Thus, we investigated the accuracies of standard IVOCT and an IVOCT enhancement algorithm for measuring PB using IVUS as the reference standard. The EEL-enhancement algorithm combined adaptive attenuation compensation, exponentiation, angular registration, and image averaging using three sequential frames. In two different laboratories with intravascular imaging expertise, PB was quantified on 200 randomized, matched IVOCT and IVUS images by four independent observers. Fibroatheroma, fibrocalcific plaque, fibrous plaque, pathological intimal thickening (PIT), and mixed plaque were included in each set. Pearson's correlation coefficients between IVUS and standard IVOCT measurements of PB were 0.61, 0.67, 0.76, 0.78, and 0.87 for fibroatheromas, mixed plaques, fibrocalcific plaques, fibrous plaques, and PIT plaques, respectively. Pearson's correlation coefficients increased to 0.81, 0.83, 0.83, 0.84, and 0.90 when using the EEL-enhanced images (P = 0.003, P = 0.004, P = 0.08, P = 0.12, and P = 0.23, respectively). EEL-enhanced IVOCT analysis was associated with a lower EEL-area measurement absolute error for fibroatheromas, mixed plaques, and all pooled plaques (P = 0.006, P = 0.02, and P < 0.001, respectively). Compared with standard IVOCT, the EEL-enhanced IVOCT images had a higher sensitivity (79% vs. 28%, P < 0.001) and specificity (98% vs. 85%, P = 0.03) for plaques with an IVUS PB ≥70%. EEL-enhanced IVOCT can be used to reliably measure PB in all types of coronary atherosclerotic lesions, including fibroatheromas and mixed plaques.

Current clinical use of intravascular ultrasound imaging to guide percutaneous coronary interventions.

During the past three decades, since the invention of intravascular ultrasound (IVUS), it has become increasingly important as daily clinical applications. However, it evolved with no Japanese standards for the measurement of images, the index of percutaneous coronary intervention (PCI) procedures, and the reporting of results. Accordingly, the purpose of this review article is to provide an optimal and consistent approach to IVUS usage during PCI for clinicians and investigators.

Application of Intravascular Imaging in Forensic Autopsy.

With the emergence of new technologies and devices including minimally invasive catheters and rotary couplers, the application of imaging technology such as traditional ultrasound and optical coherence tomography （OCT） is gradually expanded. In recent years, intravascular ultrasound （IVUS） and OCT have become increasingly mature as coronary intravascular imaging techniques, and therefore become an important complementary means of coronary angiography. Although studies on feasibility of clinical applications of IVUS and OCT have been confirmed in the evaluation of previous cadaver studies, these techniques have been neglected in forensic autopsy. This paper reviews the application value of IVUS and OCT in forensic autopsy, especially in the adjuvant evaluation of coronary artery disease. Including the characteristics of IVUS and OCT imaging technology, the problems of coronary examination in traditional autopsy and the specific application of new intravascular imaging technology in forensic autopsy.

Utility of Multimodality Intravascular Imaging and the Local Hemodynamic Forces to Predict Atherosclerotic Disease Progression

ObjectivesThis study sought to examine the utility of multimodality intravascular imaging and of the endothelial shear stress (ESS) distribution to predict atherosclerotic evolution. BackgroundThere is robust evidence that intravascular ultrasound (IVUS)-derived plaque characteristics and ESS distribution can predict, with however limited accuracy, atherosclerotic evolution; nevertheless, it is yet unclear whether multimodality imaging and ESS mapping enable more accurate prediction of coronary plaque progression. MethodsA total of 44 patients admitted with a myocardial infarction that had successful revascularization and 3-vessel IVUS and optical coherence tomography (OCT) imaging at baseline and 13-month follow-up were included in the study. The IVUS data acquired at baseline in the nonculprit vessels were fused with x-ray angiography to reconstruct coronary anatomy and in the obtained models blood flow simulation was performed and the ESS was estimated. The baseline plaque characteristics and ESS distribution were used to identify predictors of disease progression: defined as a lumen reduction and an increase in plaque burden at follow-up. ResultsSeventy-three vessels were included in the final analysis. Baseline ESS and the IVUS-derived but not the OCT-derived plaque characteristics were independently associated with a decrease in lumen area and an increase in plaque burden. Low ESS (odds ratio: 0.45; 95% confidence interval: 0.28 to 0.71; p < 0.001) and plaque burden (odds ratio: 0.73; 95% confidence interval: 0.54 to 0.97; p = 0.030) were the only independent predictors of disease progression at follow-up. The accuracy of the IVUS-derived plaque characteristics in predicting disease progression did not improve when ESS (AUC: 0.824 vs. 0.847; p = 0.127) or when OCT variables and ESS (AUC: 0.842; p = 0.611) were added into the model. ConclusionsESS and OCT-derived variables did not improve the efficacy of IVUS in predicting disease progression. Further research is required to investigate whether multimodality imaging combined with ESS mapping will allow more reliable vulnerable plaque detection. (Comparison of Biomatrix Versus Gazelle in ST-Elevation Myocardial Infarction [STEMI] [COMFORTABLE]; NCT00962416)

Coronary artery lesion phenotype in frail older patients with non-ST-elevation acute coronary syndrome undergoing invasive care

The association of frailty with coronary plaque phenotype among older patients with non-ST-elevation acute coronary syndrome (NSTEACS) is not known. The aim of this study was to evaluate the association of frailty with coronary plaque phenotype among older patients with NSTEACS. Older patients with NSTEACS who underwent invasive angiography were recruited. Frailty was measured using the Fried frailty score. Following angiography, patients underwent greyscale and virtual histology intravascular ultrasound (VH-IVUS) imaging. Of the 90 patients, 26 (28.9%) were robust, 49 (54.4%) patients were pre-frail, and 15 (16.7%) were frail. Mean age was 80.9±3.8 years; 59 (65.6%) were male. Compared to robust patients, the pre-frail group had a significantly greater presence of high-risk lesions including VH thin-cap fibroatheroma (TCFA, p=0.011), minimum lumen area (MLA) ≤4 mm2 (p=0.016), TCFA+MLA ≤4 mm2 (p=0.005), TCFA+plaque burden (PB) ≥70% (p=0.005) and TCFA+PB ≥70%+MLA ≤4 mm2 (p=0.003). By age- and sex-adjusted logistic regression analysis, frailty was found to be strongly and independently associated with the presence of TCFA (odds ratio [OR] 2.81, 95% confidence interval [CI]:1.06-7.48, p=0.039). This is the first study to report the relationship between frailty phenotype and coronary plaque morphology among frail older NSTEACS patients. ClinicalTrials.gov Identifier: NCT01933581.