Accuracy of In Vivo Coronary Plaque Morphology Assessment

Early differential changes in coronary plaque composition according to plaque stability following statin initiation in acute coronary syndrome: classification and analysis by intravascular ultrasound-virtual histology

PURPOSE

The aim of this study was to demonstrate the early effects of statin treatment on plaque composition according to plaque stability on Intravascular Ultrasound- Virtual Histology at 6 months after a coronary event. Previous trials have demonstrated that lipid lowering therapy with statins decreases plaque volume and increases plaque echogenicity in patients with coronary artery disease.

MATERIALS AND METHODS

Fifty-four patients (54 lesions) with acute coronary syndrome were prospectively enrolled. We classified and analyzed the target plaques into two types according to plaque stability: thin-cap fibroatheroma (TCFA, n=14) and non-TCFA (n=40). The primary end point was change in percent necrotic core in the 10-mm subsegment with the most disease.

RESULTS

After 6 months of statin therapy, no change was demonstrated in the mean percentage of necrotic core (18.7±8.5% to 20.0±11.0%, p=0.38). There was a significant reduction in necrotic core percentage in patients with TCFA (21.3±7.2% to 14.4±8.9%, p=0.017), but not in patients with non-TCFA. Moreover, change in percent necrotic core was significantly correlated with change in high-sensitivity C-reactive protein levels (r=0.4, p=0.003). Changes in low-density lipoprotein cholesterol levels and lipid core percentage demonstrated no significant associations.

CONCLUSION

A clear reduction of lipid core was observed only for the TCFA plaque type, suggesting that changes in plaque composition following statin therapy might occur earlier in vulnerable plaque than in stable plaque; the effect may be related to the anti-inflammatory effects of statins.

An IVUS image-based approach for improvement of coronary plaque characterization

Virtual Histology-Intravascular Ultrasound (VH-IVUS) is widely used for studying atherosclerosis plaque composition. However, one of the main limitations of the VH-IVUS relates to its dependence to the Electrocardiogram (ECG)-gated acquisition. To overcome this limitation, this paper proposes a robust image-based approach for characterization of the plaques using IVUS images. The proposed method consists of three main steps of (1) shadow detection: as an efficient preprocessing step to identify and remove acoustic shadow regions; (2) feature extraction: a combination of gray-scale based features and textural descriptors; and (3) classification: to classify each pixel into one of the three classes (calcium, necrotic core and fibro-fatty). In order to evaluate the efficiency of the proposed algorithm two in-vivo and ex-vivo data sets are considered. The kappa values of 0.639 on in-vivo and 0.628 on ex-vivo tests with VH-IVUS and the histology images labeled by the experts respectively indicate the effectiveness of the proposed algorithm.

Coronary plaque characteristics that indicate distal embolization during percutaneous coronary intervention in patients with stable angina-virtual histology intravascular ultrasound study

Distal embolization (DE) is a serious complication of percutaneous coronary intervention (PCI) in patients with stable angina. The purpose of this study was to evaluate the coronary plaque characteristics that indicate DE during PCI in patients with stable angina using virtual histology intravascular ultrasound (VH-IVUS). Three hundred and sixty-four consecutive stable angina patients who underwent PCI were enrolled in this study. The patients were divided into two groups as follows: patients exhibiting DE (DE group, n = 10) and patients without DE (non-DE group, n = 354). Coronary plaque compositions were assessed by VH-IVUS. The fibro-fatty (FF) ratio (28 ± 17 vs. 11 ± 9 %, p < 0.0001) was higher in the DE group compared with the non-DE group. The best cut-off value of FF ratio for prediction of DE was 20 %, with a sensitivity of 0.80 and a specificity of 0.81 (odds ratio; 17.1, 95 % confidence interval 3.56-82.5, p = 0.0004). Coronary plaques with a high FF ratio may be the predictor of indicating DE in patients with stable angina during PCI.

Image-based modeling and precision medicine: patient-specific carotid and coronary plaque assessment and predictions

Atherosclerotic plaques may rupture without warning and cause acute cardiovascular events such as heart attack and stroke. Current clinical screening tools are insufficient to identify those patients with risks early and prevent the adverse events from happening. Medical imaging and image-based modeling have made considerable progress in recent years in identifying plaque morphological and mechanical risk factors which may be used in developing improved patient screening strategies. The key steps and factors in image-based models for human carotid and coronary plaques were illustrated, as well as grand challenges facing the researchers in the field to develop more accurate screening tools.

Hypercholesterolemia and in-vivo coronary plaque composition in patients with coronary artery disease: a virtual histology - intravascular ultrasound study

BACKGROUND AND OBJECTIVES

Hypercholesterolemia is a key factor in the development of atherosclerosis. We sought to evaluate the relation between hypercholesterolemia and plaque composition in patients with coronary artery disease.

SUBJECTS AND METHODS

Study subjects consisted of 323 patients (mean 61.5 years, 226 males) who underwent coronary angiography and virtual histology-intravascular ultrasound examination. Patients were divided into two groups according to total cholesterol level: hypercholesterolemic group (≥200 mg/dL, n=114) and normocholesterolemic group (<200 mg/dL, n=209).

RESULTS

Hypercholesterolemic patients were younger (59.7±13.3 years vs. 62.6±11.5 years, p=0.036), than normocholesterolemic patients, whereas there were no significant differences in other demographics. Hypercholesterolemic patients had higher corrected necrotic core volume (1.23±0.85 mm(3)/mm vs. 1.02±0.80 mm(3)/mm, p=0.029) as well as percent necrotic core volume (20.5±8.5% vs. 18.0±9.2%, p=0.016) than normocholesterolemic patients. At the minimal lumen area site, percent necrotic core area (21.4±10.5% vs. 18.4±11.3%, p=0.019) and necrotic core area (1.63±1.09 mm(2) vs. 1.40±1.20 mm(2), p=0.088) were also higher than normocholesterolemic patients. Multivariate linear regression analysis showed that total cholesterol level was an independent factor of percent necrotic core volume in the culprit lesion after being adjusted with age, high density lipoprotein-cholesterol , hypertension, diabetes mellitus, smoking and acute coronary syndrome (beta 0.027, 95% confidence interval 0.02-0.053, p=0.037).

CONCLUSION

Hypercholesterolemia was associated with increased necrotic core volume in coronary artery plaque. This study suggests that hypercholesterolemia plays a role in making plaque more complex, which is characterized by a large necrotic core, in coronary artery disease.

Virtual histology analysis of carotid atherosclerotic plaque: plaque composition at the minimum lumen site and of the entire carotid plaque

BACKGROUND

Virtual Histology intravascular ultrasound (VH IVUS) volumetric analysis (analysis of the entire plaque responsible for stenosis) has been used for carotid plaque diagnosis. Knowing the carotid plaque characteristics by analyzing the plaque composition only at the minimum lumen site will facilitate plaque diagnosis using VH IVUS.

PURPOSE

To detect the relationship between the VH IVUS volumetric analysis of the entire plaque responsible for carotid artery stenosis and the VH IVUS cross-section plaque analysis at the minimum lumen site.

METHODS

Forty-eight atherosclerotic cervical carotid stenoses in 45 consecutive patients were included in the study. VH IVUS was obtained during the carotid artery stenting procedure.

RESULTS

Simple regression analysis revealed that the volumetric proportion of each plaque type correlated significantly with the corresponding plaque-type area at the minimum lumen site. The adjusted coefficients of determination of the simple regression analyses were .782 (P < .001) for fibrous tissue, .741 (P < .001) for fibrofatty tissue, .864 (P < .001) for dense calcium, and .918 (P < .001) for necrotic core.

CONCLUSION

The plaque composition at the minimum lumen site represents the volumetric composition of the entire carotid plaque that causes atherosclerotic cervical carotid artery stenosis.

Positive Vascular Remodeling in Culprit Coronary Lesion is Associated With Plaque Composition: An Intravascular Ultrasound-Virtual Histology Study

BACKGROUND AND OBJECTIVES

The relationship between the positive remodeling (PR) of a coronary artery and plaque composition has been studied only in a relatively small number of study population or non-culprit lesion. We evaluated the association between coronary plaque composition and coronary artery remodeling in a relatively large number of culprit lesions.

SUBJECTS AND METHODS

The study population consisted of 325 consecutive patients with coronary artery disease that underwent intravascular ultrasound-virtual histology examination in a culprit lesion. The remodeling index (RI) was calculated as the lesion external elastic membrane (EEM) area divided by the average reference EEM area.

RESULTS

The lesions with PR (RI>1.05, n=97, mean RI=1.19±0.12) had a higher fibrous volume/lesion length (3.85±2.12 mm(3)/mm vs. 3.04±1.79 mm(3)/mm, p=0.003) and necrotic core volume/lesion length (1.26±0.89 mm(3)/mm vs. 0.90±0.66 mm(3)/mm, p=0.001) than those with negative remodeling (NR) (RI<0.95, n=132, mean RI=0.82±0.09). At the minimal luminal area site, the lesions with PR had a higher fibrous area (5.81±3.17 mm(2) vs. 3.61±2.30 mm(2), p<0.001), dense calcified area (0.73±0.69 mm(2) vs. 0.46±0.43 mm(2), p=0.001), and necrotic core area (1.93±1.33 mm(2) vs. 1.06±0.91 mm(2), p<0.001) than those with NR. RI showed significant positive correlation with fibrous volume/lesion length (r=0.173, p=0.002), necrotic core volume/lesion length (r=0.188, p=0.001), fibrous area (r=0.347, p<0.001), fibrofatty area (r=0.111, p=0.036), dense calcified area (r=0.239, p<0.001), and necrotic core area (r=0.334, p<0.001). Multivariate analysis showed that the independent factor for PR was the necrotic core volume/lesion length (beta=0.130, 95% confidence interval; 0.002-0.056, p=0.037) over the entire lesion.

CONCLUSION

This study suggests that PR in a culprit lesion is associated with the necrotic core volume in the entire lesion, which is a characteristic of vulnerable plaque.

Virtual histology assessment of cardiac allograft vasculopathy following introduction of everolimus--results of a multicenter trial

In this 12-month multicenter Scandinavian study, 78 maintenance heart transplant (HTx) recipients randomized to everolimus with reduced calcineurin inhibitor (CNI) exposure or continued standard CNI-therapy underwent matched virtual histology (VH) examination to evaluate morphological progression of cardiac allograft vasculopathy (CAV). Parallel measurement of a range of inflammatory markers was also performed. A similar rate of quantitative CAV progression was observed in the everolimus (n = 30) and standard CNI group (n = 48) (plaque index 1.9 ± 3.8% and 1.6 ± 3.9%, respectively; p = 0.65). However, VH analysis revealed a significant increase in calcified (2.4 ± 4.0 vs. 0.3 ± 3.1%; p = 0.02) and necrotic component (6.5 ± 8.5 vs. 1.1 ± 8.6%; p = 0.01) among everolimus patients compared to controls. The increase in necrotic and calcified components was most prominent in everolimus patients with time since HTx >5.1 years and was accompanied by a significant increase in levels of von Willebrand (vWF) factor (p = 0.04) and vascular cell adhesion molecule (VCAM) (p = 0.03). Conversion to everolimus and reduced CNI is associated with a significant increase in calcified and necrotic intimal components and is more prominent in patients with a longer time since HTx. A significant increase in vWF and VCAM accompanied these qualitative changes and the prognostic implication of these findings requires further investigation.

Effect of statin therapy on the progression of coronary atherosclerosis

BACKGROUND

An increasing number of authors employing intravascular ultrasound (IVUS) and virtual histology (VH-IVUS) have investigated the effect of statin use on plaque volume (PV) and plaque composition. However, inconsistent results have been reported. Therefore, we conducted a meta-analysis to determine the appropriate regimen of statins to effectively stabilize vulnerable coronary plaques.

METHODS

Online electronic databases were carefully searched for all relevant studies. We compared mean values of PV and plaque composition between baseline and follow-up in patients receiving statin therapy. We pooled treatment effects and calculated mean differences (MD) with the 95% confidence interval (CI) using a random-effects model. By stratified analyses, we explored the influence of clinical presentation, dose and duration of statin treatment, and low-density lipoprotein-cholesterol (LDL-C) levels on the effects of statins.

RESULTS

Seventeen studies involving 2,171 patients were analyzed. Statin therapy significantly decreased PV (-5.3 mm(3); 95% CI: -3.3 mm(3) to -7.2 mm(3) P < 0.001), without heterogeneity. When considering the dose and duration of statins used, only subgroups employing a high dose and long duration demonstrated a significant reduction in PV (p < 0.001). A significant decrease in PV was noted if achieved LDL-C levels were <100 mg/dL (p < 0.001). Statin treatment could induce a twofold decrease in PV in patients with acute coronary syndrome (ACS) compared with that observed in patients with stable angina pectoris (SAP). A regressive trend was seen for necrotic core volume (MD: -2.1 mm(3); 95% CI: -4.7 mm(3) to 0.5 mm(3), P = 0.11). However, statin use did not induce a significant change for fibrotic, fibro-fatty, or dense calcium compositions.

CONCLUSIONS

Our meta-analysis demonstrated that statin therapy (especially that involving a high dose and long duration and achieving <100 mg/dL LDL-C levels) can significantly decrease PV in patients with SAP or ACS. These data suggested that statins can be used to reduce the atheroma burden for secondary prevention by appropriately selecting the statin regimen. No significant change in plaque composition was seen after statin therapy.

Association of coronary wall shear stress with atherosclerotic plaque burden, composition, and distribution in patients with coronary artery disease

Background

Extremes of wall shear stress (WSS) have been associated with plaque progression and transformation, which has raised interest in the clinical assessment of WSS. We hypothesized that calculated coronary WSS is predicted only partially by luminal geometry and that WSS is related to plaque composition.

Methods and Results

Twenty‐seven patients with coronary artery disease underwent virtual histology intravascular ultrasound and Doppler velocity measurement for computational fluid dynamics modeling for WSS calculation in each virtual histology intravascular ultrasound segment (N=3581 segments). We assessed the association of WSS with plaque burden and distribution and with plaque composition. WSS remained relatively constant across the lower 3 quartiles of plaque burden (P=0.08) but increased in the highest quartile of plaque burden (P<0.001). Segments distal to lesions or within bifurcations were more likely to have low WSS (P<0.001). However, the majority of segments distal to lesions (80%) and within bifurcations (89%) did not exhibit low WSS. After adjustment for plaque burden, there was a negative association between WSS and percent necrotic core and calcium. For every 10 dynes/cm² increase in WSS, percent necrotic core decreased by 17% (P=0.01), and percent dense calcium decreased by 17% (P<0.001). There was no significant association between WSS and percent of fibrous or fibrofatty plaque components (P=NS).

Conclusions

In patients with coronary artery disease: (1) Luminal geometry predicts calculated WSS only partially, which suggests that detailed computational techniques must be used to calculate WSS. (2) Low WSS is associated with plaque necrotic core and calcium, independent of plaque burden, which suggests a link between WSS and coronary plaque phenotype. (J Am Heart Assoc. 2012;1:e002543 doi: 10.1161/JAHA.112.002543.)

Plaque composition and clinical outcomes in acute coronary syndrome patients with metabolic syndrome or diabetes

OBJECTIVES

The goal of this study was to characterize the extent and composition of coronary atherosclerosis in patients with diabetes mellitus or the metabolic syndrome (Met Syn) presenting with acute coronary syndromes (ACS).

BACKGROUND

Diabetes and Met Syn patients have increased rates of major adverse cardiac events (MACE), yet a systematic description of nonculprit lesions for these high-risk groups is incomplete.

METHODS

In the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study, ACS patients underwent 3-vessel quantitative coronary angiography, grayscale, and radiofrequency intravascular ultrasound after successful percutaneous coronary intervention (PCI). Subsequent MACE (cardiac death or arrest, myocardial infarction, or rehospitalization for unstable or progressive angina) were adjudicated to the originally treated culprit versus untreated nonculprit lesions in 3 patient groups: 1) diabetes; 2) Met Syn; and 3) neither. Median length of follow-up was 3.4 years.

RESULTS

Of 673 patients, 119 (17.7%) had diabetes and 239 (35.5%) had Met Syn. The cumulative 3-year MACE rate was 29.4% in patients with diabetes, 21.3% with Met Syn, and 17.4% with neither (p = 0.03). MACE adjudicated to untreated nonculprit lesions occurred in 18.7%, 11.7%, and 9.7% of patients, respectively (p = 0.06). Nonculprit lesions in diabetes and Met Syn patients were longer and had greater plaque burden, smaller lumen areas, with greater necrotic core and calcium content. Diabetes and Met Syn patients with future MACE had greater necrotic core and calcification compared with the normal cardiometabolic group.

CONCLUSIONS

In this PCI ACS population, patients with diabetes and Met Syn had higher 3-year MACE rates. Lesion length, plaque burden, necrotic core, and calcium content were significantly greater among nonculprit lesions of patients with diabetes and Met Syn, but only necrotic core and calcium were significantly greater in the nonculprit lesions of patients with a future MACE in this exploratory analysis.

Current imaging modalities for atherosclerosis

Atherosclerotic disease is responsible for nearly half of all deaths in the western world. During the past three decades, considerable efforts have been made towards detection and assessment of atherosclerosis plaques in various vascular beds using different imaging techniques. Recently, both noninvasive and invasive modalities have frequently been used to refine cardiovascular risk assessment in high-risk individuals, to evaluate the natural history of atheroma burden and to reveal the impact of anti-atherosclerotic medical therapies on disease progression. In this review, we provide an overview of the currently available imaging modalities. This article will underscore arterial wall imaging to assess the impact of medical therapies on atherosclerosis and to develop the effective therapeutic strategies, resulting in the prevention of cardiovascular complications.

Coronary plaque composition, morphology, and outcomes in patients with and without chronic kidney disease presenting with acute coronary syndromes

OBJECTIVES

This study sought to evaluate the impact of chronic kidney disease (CKD) on coronary atherosclerotic plaque composition, morphology, and outcomes in patients with acute coronary syndromes (ACS).

BACKGROUND

CKD patients presenting with ACS are at increased risk for adverse events. Whether or not this increased risk reflects differences in coronary plaque composition remains unknown.

METHODS

In the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study, patients presenting with ACS in whom percutaneous coronary intervention was successful underwent 3-vessel grayscale and radiofrequency intravascular ultrasound imaging. Lesions were prospectively characterized, and patients were followed for a median of 3.4 years. We conducted a patient-level and lesion-level analysis of study participants by comparing intravascular ultrasound parameters of untreated nonculprit lesions in patients with and without CKD.

RESULTS

Patients with CKD (n = 73, 11.3%) were older, more often female and diabetic compared to those without CKD (n = 573). Nonculprit lesions in patients with (n = 280) versus without (n = 2,390) CKD were more likely to have plaque burden ≥ 70% (11.8% vs. 8.5%, p = 0.05) and minimal luminal area ≤ 4.0 mm(2) (25.9% vs. 19.2%, p = 0.005). The percentage of plaque comprised of necrotic core (15.0% vs. 13.0%, p = 0.0001) and dense calcium (8.2% vs. 6.4%, p < 0.0001) was higher while fibrous tissue (57.7% vs. 59.8%, p < 0.0001) was lower in CKD versus non-CKD lesions. The 3-year composite rate of cardiac death, cardiac arrest, or myocardial infarction (15.1% vs. 3.3%, p < 0.0001) was significantly higher in patients with than in those without CKD, although there were no differences in the rates of events adjudicated to nonculprit lesions.

CONCLUSIONS

Following percutaneous coronary intervention of all culprit lesions in ACS, patients with versus without CKD have more extensive and severe atherosclerosis remaining in their coronary tree with plaque composed of greater necrotic core and less fibrous tissue. These influences resulted in nonsignificantly different rates of non-culprit lesion-related adverse events, although cardiac death, arrest, or myocardial infarction were more common in patients with CKD.

Noninvasive, quantitative, spatiotemporal characterization of mineralization in three-dimensional collagen hydrogels using high-resolution spectral ultrasound imaging

As tissue engineering products move toward the clinic, nondestructive methods to monitor their development and ensure quality are needed. In this study, high-resolution spectral ultrasound imaging (SUSI) was used to noninvasively characterize mineral content in collagen hydrogels. SUSI was used to generate three-dimensional (3D) grayscale (GS) images of construct morphology with submillimeter resolution. Spectral analysis of the backscattered radio frequency (RF) ultrasound signals was used to determine the midband fit (MBF) and slope of the linearized RF spectrum. These parameters are operator and instrument independent, and were used to characterize the spatial distribution of mineral in constructs supplemented with hydroxyapatite particles. GS and MBF correlated closely with mineral content, while slope was not dependent on concentration. SUSI also was used to monitor mineralization of collagen constructs by immersion in simulated body fluid (SBF) over 21 days. The construct surface was mineralized before the interior, and there was a dose-dependent effect of SBF concentration on degree of mineralization and deposited particle size. MBF density was closely correlated with the amount of calcium deposited. These data demonstrate that SUSI has utility as a noninvasive imaging method for quantitative analysis of mineralization in 3D protein constructs. Such techniques may assist the development of engineered orthopedic tissues.

Prediction of distal embolization during percutaneous coronary intervention for unstable plaques with grayscale and integrated backscatter intravascular ultrasound

OBJECTIVES

We performed microscopic examination of the debris collected by a distal protection device and investigated the usefulness of grayscale and integrated backscatter intravascular ultrasound (IB-IVUS) for the prediction of distal embolization during percutaneous coronary intervention (PCI) in cases of unstable angina.

BACKGROUND

The prediction of distal embolization during PCI has not been studied in depth because assessment of distal embolization is difficult.

METHODS

We prospectively studied 39 consecutive patients with unstable angina who underwent PCI with a filter distal protection device. The preprocedural plaque volume at target lesions was measured with grayscale IVUS and plaque characteristics were assessed with IB-IVUS. We performed microscopic examination of the particles collected by the distal protection device.

RESULTS

There was a significant correlation between the plaque volume and the number of the collected particles >100 μm in diameter (r = 0.48, P = 0.0034). Filter no-reflow (FNR) phenomenon was found in nine patients. The plaque volume was significantly greater (355 ± 133 mm(3) vs. 199 ± 90 mm(3) , P = 0.0004), and the lipid ratio was significantly higher (29.3 ± 4.3% vs. 26.1 ± 4.3 P = 0.045) in the FNR group compared with the non-FNR group. Multivariate logistic regression analysis showed that the plaque volume was an independent predictor of FNR phenomenon.

CONCLUSIONS

Although tissue characterization of IB-IVUS may provide additional information for distal embolization, plaque volume is the only significant predictor of distal embolization during PCI.

Impact of Statin Use Before the Onset of Acute Myocardial Infarction on Coronary Plaque Morphology of the Culprit Lesion

Statins favorably stabilize coronary plaque. We evaluated the impact of statin use before the onset of acute myocardial infarction (AMI) on culprit lesion plaque morphology. Patients (n = 127) with AMI were divided into either a statin group (n = 31) or a nonstatin group (n = 96) based on statin use before the onset of AMI. Coronary plaque morphology of the culprit lesion was evaluated using intravascular ultrasound virtual histology (IVUS-VH) with radiofrequency data analysis before coronary intervention. The IVUS-VH identified 4 types of plaque components: fibrous, fibrofatty, dense calcium, and necrotic core. The IVUS-VH showed less percentage of necrotic area, greater percentage fibrous area, and greater percentage of fibrofatty area of the culprit lesion in the statin group. In conclusion, statin use before the onset of AMI might have effects on coronary plaque morphology of the AMI culprit lesion with less necrotic core and greater fibrous and fibrofatty component.

Characterization of the pancreas in vivo using EUS spectrum analysis with electronic array echoendoscopes

BACKGROUND

Spectral analysis of the radiofrequency (RF) signals that underlie grayscale EUS images has been used to provide quantitative, objective information about tissue histology.

OBJECTIVE

Our purpose was to validate RF spectral analysis as a method to distinguish between chronic pancreatitis (CP) and pancreatic cancer (PC).

DESIGN AND SETTING

A prospective study of eligible patients was conducted to analyze the RF data obtained by using electronic array echoendoscopes.

PATIENTS

Pancreatic images were obtained by using electronic array echoendoscopes from 41 patients in a prospective study, including 15 patients with PC, 15 with CP, and 11 with a normal pancreas.

MAIN OUTCOME MEASUREMENTS

Midband fit, slope, intercept, correlation coefficient, and root mean square deviation from a linear regression of the calibrated power spectra were determined and compared among the groups.

RESULTS

Statistical analysis showed that significant differences were observable between groups for mean midband fit, intercept, and root mean square deviation (t test, P < .05). Discriminant analysis of these parameters was then performed to classify the data. For CP (n = 15) versus PC (n = 15), the same parameters provided 83% accuracy and an area under the curve of 0.83.

LIMITATIONS

Moderate sample size and spatial averaging inherent in the technique.

CONCLUSIONS

This study shows that mean spectral parameters of the backscattered signals obtained by using electronic array echoendoscopes can provide a noninvasive method to quantitatively discriminate between CP and PC.

Virtual histology-intravascular ultrasound assessment of lesion coverage after angiographically-guided stent implantation in patients with ST Elevation myocardial infarction undergoing primary percutaneous coronary intervention

An occlusion or severe stenosis (angiographic culprit lesion) of the infarct-related artery is frequently located at the site of the maximum thrombus burden, whereas the origin of the plaque rupture (the true culprit) can be situated proximal or distal to it. The aim of this study was to examine stent coverage of true culprit lesions in 20 patients who underwent primary percutaneous coronary intervention and had Thrombolysis In Myocardial Infarction (TIMI) grade 3 flow restored in the infarct-related artery by angiographically guided direct stenting. Images of lesions were obtained using virtual histology-intravascular ultrasound before and after intervention (blinded to the operator). Plaque rupture sites were identified by intravascular ultrasound in 12 lesions (60%), 11 proximal and 1 distal to the minimum luminal area (MLA). Maximum necrotic core sites were found proximal to the MLA in 16 lesions, at the MLA in 3 lesions, and distal to the MLA in 1 lesion. Plaque rupture sites were fully covered by stents in 11 lesions. Virtual histology-intravascular ultrasound-derived thin-cap fibroatheroma longitudinal geographic misses were found in 10 lesions, 7 in the proximal reference segment and in 3 patients in the proximal and distal reference segments. In conclusion, in about 50% of patients who undergo primary percutaneous coronary intervention for ST-segment elevation myocardial infarction with optimal angiographic results, the stent does not fully cover the maximum necrotic core site related to the culprit lesion.

Correlations between coronary plaque tissue composition assessed by virtual histology and blood levels of biomarkers for coronary artery disease

PURPOSE

We investigated correlations of coronary plaque composition determined by virtual histology (VH) intravascular ultrasound (IVUS) and blood levels of biomarkers that represent the vulnerability of coronary plaques.

MATERIALS AND METHODS

Pre- and postprocedural blood levels of high sensitivity C-reactive protein, soluble CD40 ligand (sCD40L), matrix metalloproteinase-9, and neopterin were measured in 70 patients with stable angina (SA) or unstable angina (UA) who were undergoing percutaneous coronary intervention (PCI) for single lesions. We evaluated the data for correlations between these biomarkers and necrotic core contents in PCI target lesions analyzed by VH.

RESULTS

Clinical characteristics, IVUS, VH, and biomarker blood levels were not different between the SA and the UA group except for more frequent previous statin use (52.3% vs. 23.1%, p=0.017) and lower remodeling index in the SA group (0.98±0.09 vs. 1.10±0.070, p<0.001). Among the biomarkers evaluated, only pre-PCI neopterin level showed a weakly significant correlation with the absolute volume of the necrotic core (r=0.320, p=0.008). Pre- and post-PCI blood levels of sCD40L (r=0.220, p=0.072; r=0.231, p=0.062) and post-PCI blood level of neopterin (r=0.238, p=0.051) showed trends toward weakly positive correlations with the absolute volume of necrotic core.

CONCLUSION

We found a weakly positive correlation between the pre-PCI neopterin level and necrotic core volume in the PCI-target lesion. The clinical implications of our findings need to be investigated in further studies.

Composition and plaque patterns of coronary culprit lesions and clinical characteristics of patients with chronic kidney disease

Coronary artery disease is a serious complication of chronic kidney disease (CKD); however, there is little information about coronary plaque morphology in these patients. Here we identified the characteristics of coronary culprit plaques and their clinical manifestations in 78 patients with CKD divided into four groups based on their estimated glomerular filtration rate. Patients were examined by Virtual Histology-Intravascular Ultrasound, a tomographic imaging method that can visualize atherosclerotic plaques in vivo using radiofrequency analysis of ultrasound backscatter signals. These ultrasound analyses showed an increase in the relative volumes of both dense calcium and necrotic core with decreasing renal function. The necrotic core/dense calcium ratio was significantly higher in patients with acute myocardial infarction compared to those with stable angina pectoris. Furthermore, the necrotic core/dense calcium ratio decreased in advanced CKD. Thus, the plaque composition of coronary culprit lesions changed from necrotic core-rich to extensively calcium-rich plaques as renal function decreased, suggesting that such coronary culprit composition was associated with stability, particularly in advanced CKD.

Low density lipoprotein-cholesterol/high density lipoprotein-cholesterol ratio predicts plaque vulnerability in patients with stable angina

BACKGROUND AND OBJECTIVES

The relationship between lipid profile and coronary plaque tissue characteristics in patients with stable angina pectoris (SAP) is unclear. The aim of this study was to evaluate the relationship between tissue characteristics and lipid profile and predictors of unstable plaques (UPs) in patients with SAP by virtual histology intravascular ultrasonography (VH-IVUS).

SUBJECTS AND METHODS

VH-IVUS was performed for target lesions in patients with SAP (61.7±9.2 years, 174 males, n=266) at the time of coronary angiography. UPs are characterized by thin-cap fibroatheroma, ruptured plaque, or remaining thrombus with VH-IVUS.

RESULTS

The present study showed that 34 SAP patients had UPs (61.6±9.2 years, 24 males, 12.8%). The percentage of plaque area in the minimum luminal area in high low density lipoprotein-cholesterol (LDL-C)/high density lipoprotein-cholesterol (HDL-C) ratio patients was significantly higher than in low LDL-C/HDL-C ratio patients (72.7±9.5% vs. 69.9±9.3%, p=0.035). An LDL-C/HDL-C ratio >2.0 was an independent predictor for UPs in SAP patients (odds ratio 5.252, 95% confidence interval 1.132-24.372, p=0.034).

CONCLUSION

An elevated LDL-C/HDL-C ratio is a positive predictor for coronary plaque vulnerability in patients with SAP.

Relation of ruptured plaque culprit lesion phenotype and outcomes in patients with ST elevation acute myocardial infarction

We used virtual histology intravascular ultrasound (VH-IVUS) to assess culprit plaque rupture in 172 patients with ST-segment elevation acute myocardial infarction. VH-IVUS-defined thin-capped fibroatheroma (VH-TCFA) had necrotic core (NC) > 10% of plaque area, plaque burden > 40%, and NC in contact with the lumen for ≥ 3 image slices. Ruptured plaques were present in 72 patients, 61% of which were located in the proximal 30 mm of a coronary artery. Thirty-five were classified as VH-TCFA and 37 as non-VH-TCFA. Vessel size, lesion length, plaque burden, minimal lumen area, and frequency of positive remodeling were similar in VH-TCFA and non-VH-TCFA. However, the NC areas within the rupture sites of VH-TCFAs were larger compared to non-VH-TCFAs (p = 0.002), while fibrofatty plaque areas were larger in non-VH-TCFAs (p < 0.0001). Ruptured plaque cavity size was correlated with distal reference lumen area (r = 0.521, p = 0.00002), minimum lumen area (r = 0.595, p < 0.0001), and plaque area (r = 0.267, p = 0.033). Sensitivity and specificity curve analysis showed that a minimum lumen area of 3.5 mm2, a distal reference lumen area of 7.5 mm2, and a maximum NC area of 35% best predicted plaque rupture. Although VH-TCFA (35 of 72) was the most frequent phenotype of plaque rupture in ST-segment elevation myocardial infarction, plaque rupture also occurred in non-VH-TCFA: pathologic intimal thickening (8 of 72), thick-capped fibroatheroma (1 of 72), and fibrotic (14 of 72) and fibrocalcified (14 of 72) plaque. In conclusion, not all culprit plaque ruptures in patients with ST-segment elevation myocardial infarction occur as a result of TCFA rupture; a prominent fibrofatty plaque, especially in a proximal vessel, may be another form of vulnerable plaque. Further study should identify additional factors causing plaque rupture.

The maximum necrotic core area is most often located proximally to the site of most severe narrowing: a virtual histology intravascular ultrasound study

Previous angiographic studies have shown that almost two-thirds of vulnerable plaques are located in non-obstructive lesions. Possibly, the maximum necrotic core (Max NC) area is not always identical to the site of most severe stenosis. Therefore, the purpose of this study was to evaluate the potential difference in location between the maximum necrotic core area and the site of most severe narrowing as assessed by virtual histology intravascular ultrasound (VH IVUS). Overall, 77 patients (139 vessels) underwent VH IVUS. The Max NC site was defined as the cross section with the largest necrotic core area per vessel. The site of most severe narrowing was defined as the minimum lumen area (MLA). Per vessel, the distance from both the Max NC site and MLA site to the origo of the coronary artery was evaluated. In addition, the presence of a virtual histology-thin cap fibroatheroma (VH-TCFA) was assessed. The mean difference (mm) between the MLA site and Max NC site was 10.8 ± 20.6 mm (p < 0.001). Interestingly, the Max NC site was located at the MLA site in seven vessels (5%) and proximally to the MLA site in 92 vessels (66%). Importantly, a higher percentage of VH-TCFA was demonstrated at the Max NC site as compared to the MLA site (24 vs. 9%, p < 0.001). In conclusion, the present findings demonstrate that the Max NC area is rarely at the site of most severe narrowing. Most often, the Max NC area is located proximal to the site of most severe narrowing.

Cardiac CT in the emergency department

Current triage strategies are not effective in correctly identifying patients suffering from acute coronary syndrome (ACS). The diagnostic workup of patients presenting with acute chest pain continues to represent a major challenge for emergency department (ED) personnel. This statement holds especially true for patients with a low to intermediate likelihood for ACS. Taking current concepts for the diagnosis and management of patients presenting with acute chest pain to the ED into account, this article discusses the evidence and potential role of coronary computed tomography angiography to improve management of patients with possible ACS.

Fibro-Fatty Component is Important for the Long-Term Clinical Events in Patients Who Have Undergone Primary Percutaneous Coronary Intervention

Background and Objectives

We evaluated which plaque components are associated with long-term clinical events in patients who underwent primary percutaneous coronary intervention (PCI).

Subjects and Methods

The study subjects consisted of 57 consecutive patients (mean age, 58.5±14.5 years; 45 males) who underwent primary PCI and a virtual histology-intravascular ultrasound examination. Major adverse cardiac events (MACEs) including death, acute myocardial infarction, stroke, and revascularization were evaluated during the mean 28 month follow-up period.

Results

Patients with high fibro-fatty volume (FFV >13.4 mm³, n=29; mean age, 61.3 years) had a lower ejection fraction (52.7% vs. 59.4%, p=0.022), a higher incidence of multi-vessel disease (69.0% vs. 28.6%, p=0.002), larger plaque area (25.7 mm² vs. 15.9 mm², p<0.001), and larger plaque volume (315 mm³ vs. 142 mm³, p<0.001) than those with a low FFV (≤13.4 mm³, n=28; mean age, 55.6 years). Patients with high FFV had a significantly higher incidence (32.1% vs. 8.3%, p=0.036) of MACE than those with low FFV. When we divided the study population according to the necrotic core volume (NCV), fibrous volume, or dense calcified volume, no significant findings in terms of demographics and MACE rates were observed. A Cox regression analysis revealed that the independent factor for MACE was FFV (hazard ratio, 6.748; 95% confidence interval, 1.168-38.971, p=0.033) in this study population.

Conclusion

The coronary plaque component, particularly FFV, but not NCV, was important in long-term clinical outcomes in patients who underwent primary PCI.

Multicenter assessment of the reproducibility of volumetric radiofrequency-based intravascular ultrasound measurements in coronary lesions that were consecutively stented

To assess in a multicenter design the between-center reproducibility of volumetric virtual histology intravascular ultrasound (VH-IVUS) measurements with a semi-automated, computer-assisted contour detection system in coronary lesions that were consecutively stented. To evaluate the reproducibility of volumetric VH-IVUS measurements, experienced analysts of 4 European IVUS centers performed independent analyses (in total 8,052 cross-sectional analyses) to obtain volumetric data of 40 coronary segments (length 20.0 ± 0.3 mm) from target lesions prior to percutaneous intervention that were performed in the setting of stable (65%) or unstable angina pectoris (35%). Geometric and compositional VH-IVUS measurements were highly correlated for the different comparisons. Overall intraclass correlation for vessel, lumen, plaque volume and plaque burden was 0.99, 0.92, 0.96, and 0.83, respectively; for fibrous, fibro-lipidic, necrotic core and calcified volumes overall intraclass correlation was 0.96, 0.94, 0.98, and 0.99, respectively. Nevertheless, significant differences for both geometrical and compositional measurements were seen. Of the plaque components, fibrous tissue and necrotic core showed on average the highest measurement reproducibility. A central analysis for VH-IVUS multicenter studies of lesions prior to PCI should be pursued. Moreover, it may be problematical to pool VH-IVUS data of individual trials analyzed by independent centers.

Deviation from Murray's law is associated with a higher degree of calcification in coronary bifurcations

OBJECTIVE

Murray's law describes the optimal branching anatomy of vascular bifurcations. If Murray's law is obeyed, shear stress is constant over the bifurcation. Associations between Murray's law and intravascular ultrasound (IVUS) assessed plaque composition near coronary bifurcations have not been investigated previously.

METHODS

In 253 patients plaque components (fibrous, fibro-fatty, necrotic core, and dense calcium) were identified by IVUS in segments proximal and distal to the bifurcation of a coronary side branch. The ratio of mother to daughter vessels was calculated according to Murray's law (Murray ratio) with a high Murray ratio indicating low shear stress. Analysis of variance was used to detect independent associations of Murray ratio and plaque composition.

RESULTS

Patients with a high Murray ratio exhibited a higher relative amount of dense calcium and a lower amount of fibrous and fibro-fatty tissue than those with a low Murray ratio. After adjustment for age, sex, cardiovascular risk factors or concomitant medications, the Murray ratio remained significantly associated with fibrous volume distal (F-ratio 4.90, P=0.028) to the bifurcation, fibro-fatty volume distal (F-ratio 4.76, P=0.030) to the bifurcation, and dense calcium volume proximal (F-ratio 5.93, P=0.016) and distal (F-ratio 5.16, P=0.024) to the bifurcation.

CONCLUSION

This study shows that deviation from Murray's law is associated with a high degree of calcification near coronary bifurcations. Individual deviations from Murray's law may explain why some patients are prone to plaque formation near vessel bifurcations.

Combined two-photon luminescence microscopy and OCT for macrophage detection in the hypercholesterolemic rabbit aorta using plasmonic gold nanorose

BACKGROUND AND OBJECTIVES

The macrophage is an important early cellular marker related to risk of future rupture of atherosclerotic plaques. Two-channel two-photon luminescence (TPL) microscopy combined with optical coherence tomography (OCT) was used to detect, and further characterize the distribution of aorta-based macrophages using plasmonic gold nanorose as an imaging contrast agent.

STUDY DESIGN/MATERIALS AND METHODS

Nanorose uptake by macrophages was identified by TPL microscopy in macrophage cell culture. Ex vivo aorta segments (8 × 8 × 2 mm(3) ) rich in macrophages from a rabbit model of aorta inflammation were imaged by TPL microscopy in combination with OCT. Aorta histological sections (5 µm in thickness) were also imaged by TPL microscopy.

RESULTS

Merged two-channel TPL images showed the lateral and depth distribution of nanorose-loaded macrophages (confirmed by RAM-11 stain) and other aorta components (e.g., elastin fiber and lipid droplet), suggesting that nanorose-loaded macrophages are diffusively distributed and mostly detected superficially within 20 µm from the luminal surface of the aorta. Moreover, OCT images depicted detailed surface structure of the diseased aorta.

CONCLUSIONS

Results suggest that TPL microscopy combined with OCT can simultaneously reveal macrophage distribution with respect to aorta surface structure, which has the potential to detect vulnerable plaques and monitor plaque-based macrophages overtime during cardiovascular interventions.

Optimal cutoff threshold for calcium quantification in isotropic CT calcium scans by validating against registered intravascular ultrasound with radiofrequency backscatter

3D Computed Tomography (CT) provides noninvasive, low-radiation method of coronary artery calcium (CAC) measurement. Conventional CAC images are acquired on multidetector-row CT scanners without contrast, and reconstructed with 3 mm slice thickness. The calcium volume is quantified by registering voxels with attenuation values greater than or equal to 130 Hounsfield Unit (HU). In isotropic CAC images with 0.5 mm slice thickness obtained from 320-detector row CT, the optimal value of attenuation cutoff threshold is unknown. In this paper we find the optimal cutoff threshold for calcium quantification in isotropic CT calcium scans by validating against registered intravascular ultrasound with radiofrequency backscatter (IVUS/VH). From the statistical analysis of calcium data obtained from the images of 9 patients we found a range of optimal thresholds and the conventional threshold of 130 HU was in the range. Further, the optimal values were different for individual patients.

Effect of statins on coronary bifurcation atherosclerosis: an intravascular ultrasound virtual histology study

This study is aimed at assessing by intravascular ultrasound virtual histology (VH-IVUS) the effect of statins on coronary bifurcation atherosclerosis in non-culprit vessels. In this non-randomized study, in 48 patients, 51 bifurcation atherosclerotic sites in non-culprit vessels without significant angiographic stenosis, underwent baseline and 12 months follow-up VH-IVUS. Patients received treatment with either simvastatin (20 mg daily, n = 24) or rosuvastatin (10 mg daily, n = 24) for the same period. VH-IVUS analysis of bifurcation lesions included the 5-mm proximal, bifurcation only (side-branch point) and 5-mm distal subsegments. Overall plaque and external elastic membrane volume decreased after 1 year (115.7 ± 35.5 to 106.1 ± 29.3 mm³, P < 0.001; and 241.0 ± 57.0 to 232.4 ± 54.2 mm³, P = 0.005, respectively). Similarly, overall dense calcium volume significantly increased (7.1 ± 5.3 to 11.0 ± 8.5 mm³, P < 0.010), while fibrous and fibrofatty volumes significantly decreased (36.9 ± 19.2 to 24.1 ± 11.7 mm³, P < 0.001; and 5.1 ± 3.8 to 2.3 ± 2.0 mm³, P < 0.001, respectively), and necrotic core volume did not change significantly (17.0 ± 11.1 to 19.8 ± 13.5 mm³, P = 0.053). There were no significant differences in compositional analysis between the simvastatin and rosuvastatin treatment groups. However, within groups, necrotic core volume significantly increased in the simvastatin treatment group (19.7 ± 13.9 to 24.3 ± 16.1 mm³, P = 0.029) but not in the rosuvastatin treatment group. (14.3 ± 6.7 to 15.6 ± 8.7 mm³, P = 0.423). The independent clinical predictors for reduction of necrotic core volume by multiple stepwise logistic regression analysis were the percent change of HDL-cholesterol level (P = 0.041, odds ratio: 1.052, 95% confidence interval (CI): 1.002 to 1.104) and the percent change of hsCRP level (P = 0.021, odds ratio: 0.989, 95% CI: 0.980 to 0.998). After 1 year, overall dense calcium volume significantly increased whilst fibrous and fibrofatty volumes significantly decreased; no significant change in the content of necrotic core was observed. Although changes in the volumes of all plaque components were not significantly different between the simvastatin and rosuvastatin treatment groups, halting of necrotic core progression was apparent in the rosuvastatin group.

Possible association between non-invasive parameter of flow-mediated dilatation in brachial artery and whole coronary plaque vulnerability in patients with coronary artery disease

BACKGROUND

Despite being a relatively widely-used non-invasive parameter of endothelial dysfunction, little is known regarding the relationship between flow-mediated dilatation (FMD) and coronary plaque vulnerability in patients with coronary artery disease (CAD).

METHODS

111 CAD patients (age; 68.9 ± 9.3) who underwent both coronary intervention and FMD were enrolled. Spectral analyses of intravascular ultrasound radiofrequency data for both culprit and non-culprit lesions were performed using Virtual Histology software. Plaque burden was described based on fibrotic, fibro-fatty, dense calcium, and necrotic core (NC) components, and thin-cap fibroatheroma (TCFA) was defined as focal NC rich (> 10%) plaques touching the lumen with a percent-plaque volume exceeding 40%.

RESULTS

Averaged %FMD was 2.86 ± 2.03% (median 2.27%, 25th 1.40%, 75th 4.20%). NC volumes were negatively correlated with log%FMD for both culprit and non-culprit lesions (P = 0.001, r = 0.31 and P = 0.03, r = 0.21, respectively). We divided the patients into three tertiles according to %FMD; 38 were lower (≤ 1.75%), 41 were middle (> 1.75%, but ≤ 3.5%), and 32 were upper tertile (> 3.5%). The prevalence rate of TCFA increased with decreasing %FMD tertile and the incidence of major adverse cardiac events was significantly higher in lower %FMD tertile. Multivariate logistic regression analyses showed that the most powerful predictive factor for TCFA was log%FMD (P < 0.0001), and ROC curve analysis identified %FMD of < 2.81% (AUC = 0.82, sensitivity: 91.2%, specificity: 66.7%) as the optimal cut-off point for predicting the presence of TCFA.

CONCLUSIONS

Impaired endothelial function in brachial arteries may be associated with whole coronary plaque vulnerability and poor clinical outcome in patients with CAD.

The association between renal atherosclerotic plaque characteristics and renal function before and after renal artery intervention

OBJECTIVE

To evaluate the effect of plaque composition on renal function after renal artery intervention (RAI).

PATIENTS AND METHODS

In 33 consecutive patients with atherosclerotic renal artery stenosis (enrolled between January 1, 2007, and April 30, 2009), renal angiography, pressure gradients across the lesion, and intravascular ultrasonography (IVUS) with virtual histology (VH)-derived plaque characteristics were assessed. In 25 patients who underwent RAI, estimated glomerular filtration rate (eGFR) was evaluated at baseline and at 3 months.

RESULTS

Mean pressure gradients across the lesion were poorly associated with baseline eGFR (r=-0.37; P=.07). In gray scale IVUS data, only remodeling index was significantly correlated with baseline eGFR (r=-0.38; P=.03). Plaque components classified by VH-IVUS had no correlation with baseline eGFR. During follow-up of 25 patients, the improvement in eGFR after RAI was observed in 9 patients, unchanged in 3, and deteriorated in 13. Overall, follow-up eGFR (median, 49.0 mL/min/1.73 m(2); interquartile range [IQR], 40.6-63.9 mL/min/1.73 m(2)) was unchanged compared with baseline eGFR (median, 53.8 mL/min/1.73 m(2); IQR, 41.4-63.4 mL/min/1.73 m(2); P=.38). The percent change in eGFR (median, -0.2%; IQR, -16.0% to 16.0%) after RAI had a significant negative correlation with the mean percentage of necrotic core classified by VH-IVUS (r=-0.47; P=.02), and the mean percentage of necrotic core was significantly larger in patients with deterioration of eGFR than in patients without deterioration of eGFR (median, 12.7%; IQR, 9.5%-19.5%; vs median, 8.3%; IQR, 5.5%-11.6%; P=.04).

CONCLUSION

In patients with atherosclerotic renal artery stenosis, the change in eGFR after RAI was related to plaque composition classified by VH-IVUS. The evaluation of plaque composition may provide more insights into the change in renal function after RAI.

Comprehensive assessment of spotty calcifications on computed tomography angiography: comparison to plaque characteristics on intravascular ultrasound with radiofrequency backscatter analysis

BACKGROUND

The purpose of the study was to systematically compare calcification patterns in plaques on computed tomography angiography (CTA) with plaque characteristics on intravascular ultrasound with radiofrequency backscatter analysis (IVUS-VH).

METHODS AND RESULTS

In total, 108 patients underwent CTA and IVUS-VH. On CTA, calcification patterns in plaques were classified as non-calcified, spotty or dense calcifications. Plaques with spotty calcifications were differentiated into small spotty (<1 mm), intermediate spotty (1-3 mm) and large spotty calcifications (≥3 mm). Plaque characteristics deemed more high-risk on IVUS-VH were defined by % necrotic core (NC) and presence of thin cap fibroatheroma (TCFA). Overall, 300 plaques were identified both on CTA and IVUS-VH. % NC core was significantly higher in plaques with small spotty calcifications as compared to non-calcified plaques (20% vs 13%, P = .006). In addition, there was a trend for a higher % NC in plaques with small spotty calcifications than in plaques with intermediate spotty calcifications (20% vs 14%, P = .053). Plaques with small spotty calcifications had the highest % TCFA as compared to large spotty and dense calcifications (31% vs 9% and 31% vs 6%, P < .05).

CONCLUSION

Plaques with small spotty calcifications on CTA were related to plaque characteristics deemed more high-risk on IVUS-VH. Therefore, CTA may be valuable in the assessment of the vulnerable plaque.

Long-term outcome of percutaneous coronary intervention: the significance of native coronary artery disease progression

The extensive use of stents during percutaneous coronary intervention (PCI) is associated with concerns about their potential adverse effects. In-stent restenosis and stent thrombosis definitely significantly affect the PCI outcome. However, review of recent relevant studies suggests that stent-related problems may have been somewhat overestimated when compared to coronary artery disease (CAD) progression at nonstented coronary segments as causative factors of adverse cardiac clinical events late (>30 days) post-PCI. Both stent-related problems and native CAD progression have to be equally addressed to optimize the PCI clinical benefit.

Visualization of coronary plaque in type 2 diabetes mellitus patients using a new 40 MHz intravascular ultrasound imaging system

BACKGROUND

Previous epidemiological studies demonstrated plaque vulnerability to be high in diabetic patients. iMap-intravascular ultrasound (IVUS) is a recently developed radiofrequency 40 MHz IVUS imaging system for tissue characterization. This study aimed to characterize coronary plaque in target lesions of diabetic patients using iMap-IVUS.

METHODS

We studied 175 treated vessels in 146 patients with stable angina pectoris and analyzed plaque components of culprit lesions by iMAP-IVUS. Patients were divided into 2 groups: non-diabetic (non-DM: 112 vessels, 93 patients) and diabetic (DM: 63 vessels, 53 patients).

RESULTS

In gray-scale IVUS 2D analysis, there were no differences in IVUS parameters. In 3D analysis, the DM group tended to have a larger plaque volume (p=0.07) and plaque burden (p=0.10). At minimum lumen sites, the absolute lipidic and necrotic areas (0.84 ± 0.44 mm(2) vs. 0.58 ± 0.41 mm(2), p<0.001, and 2.42 ± 1.65 mm(2) vs. 1.46 ± 1.76 mm(2), p<0.001, respectively) and percent lipidic and necrotic areas were significantly greater in the DM than in the non-DM group (8.39 ± 3.38% vs. 5.25 ± 2.30%, p<0.0001, and 23.65 ± 11.54% vs. 12.99 ± 10.71%, p<0.0001, respectively). In addition, the absolute lipidic and necrotic volumes (11.75 ± 10.59 mm(3) vs. 8.18 ± 6.24 mm(3), p<0.01, and 29.99 ± 28.90 mm(3) vs. 19.44 ± 19.35 mm(3), p<0.01, respectively) and percent lipidic and necrotic volumes were significantly greater in the DM than in the non-DM group (6.27 ± 1.92% vs. 5.13 ± 1.82%, p<0.0001, and 16.54 ± 7.56% vs. 12.08 ± 6.05%, p<0.0001, respectively).

CONCLUSION

Characterization of coronary plaque by iMAP-IVUS in diabetic patients showed increased lipidic amount and necrotic plaque volume relative to subjects without DM.

A patient with significant slow-flow phenomenon during percutaneous coronary intervention for ST elevation myocardial infarction associated with scattered necrotic core by virtual histology intravascular ultrasound

A 68-year-old man with acute ST elevation myocardial infarction (STEMI) underwent emergent coronary angiography which showed total occlusion in the proximal right coronary artery (RCA). Gray-scale intravascular ultrasound (IVUS) revealed the culprit lesion was expansively remodeled and contained ruptured and echolucent plaques with spotty calcification, whereas thin-capped fibroatheroma and a large amount of scattered necrotic core were observed by virtual histology (VH)-IVUS. After stent implantation in the proximal RCA under a filter protection, filter-no-reflow phenomenon occurred and thrombus-like defect was observed in the mid RCA. Under these conditions, VH-IVUS detected a large amount of scattered necrotic core in the mid RCA. We suggest scattered necrotic core detected by VH-IVUS may be associated with slow-flow phenomenon during percutaneous coronary intervention in our patient with STEMI.