冠心病患者心外膜脂肪体积与血管重构类型有关联

目的:观察分析冠心病患者心外膜脂肪体积（EATV）与血管重构类型的相关性。方法: 行64排双源CT评估冠状动脉狭窄程度并测定EATV,同期行外周血脂、胰岛素抵抗指数等检测。经数字减影血管造影（DSA）确诊冠心病患者180例。经CT血管造影（CTA)图像测定斑块重构指数(RI),根据RI将患者分为正性重构组（80例）和负性/无重构组（100例）,并分析其与EATV的相关性。结果: 正性重构组的EATV显著增加［(128±42) cm3 vs.(95±25) cm3］。logistic回归分析显示EATV是影响正性重构的独立危险因素。结论: EATV是影响冠心病病变血管正性重构的独立危险因素。     

Relationship between tissue characterization with 40 MHz intravascular ultrasound imaging and 64-slice computed tomography

BackgroundIdentification of coronary plaque composition is important for selecting the treatment strategy, and 64-slice computed tomography (CT) is a noninvasive method of characterizing atherosclerotic plaques. However, the correlation between plaque characteristics detected by CT and intravascular ultrasound (IVUS) is not clear. A 40 MHz IVUS imaging system (iMap-IVUS) has recently been developed to evaluate plaque composition. The aim of this study was to compare iMap-IVUS with 64-slice CT angiography for the characterization of non-calcified coronary plaques.Methods and resultsBoth 64-slice CT angiography and iMap-IVUS were performed in 19 patients (38 plaques). CT values were measured as Hounsfield units (HU) in circular regions of interest (ROI) drawn on the plaques. The iMap-IVUS system analyzed coronary plaques as fibrotic, lipidic, necrotic, or calcified tissue based on the radiofrequency spectrum.A positive correlation was found between CT values and the percentage of fibrotic plaque (r = 0.34, p = 0.036) or calcified plaque (r = 0.40, p = 0.011). Conversely, a negative correlation was found between CT values and the percentage of lipidic plaque (r = ?0.41, p = 0.01), or necrotic plaque (r = ?0.41, p = 0.01).ConclusionsGood correlations were observed between the characteristics of non-calcified plaque determined by iMap-IVUS and the CT values of plaque detected by 64-slice CT scanning.     

Virtual histology by intravascular ultrasound study on degenerative aortocoronary saphenous vein grafts

Data of virtual histology (VH) acquired by intravascular ultrasound (IVUS) on saphenous vein graft (SVG) lesions is lacking. This study sought to report the VH IVUS findings in degenerative aortocoronary SVG lesions and correlate various types of plaque compositions (fibrous, fibro-fatty, dense calcium, and necrotic core) with different clinical and lesion characteristics. Virtual histology IVUS was performed on SVG in 38 symptomatic patients with a history of coronary artery bypass grafting, who underwent percutaneous coronary intervention on either native vessels or SVG. Measurements were made at the image slice with the smallest lumen. A total of 54 SVG lesions were analyzed; the mean graft age was 13.7 ± 4.0 years. The mean vessel size was 5.0 ± 1.0 mm; plaque area was 13.4 ± 7.3 mm², and plaque burden was 63.0% ± 15.0%. Fibrous tissue represented the major plaque component (62.1% ± 17.1%). Lesions with a plaque burden of ≥70% were associated with positive remodeling, larger vessel size, higher percentage of fibro-fatty tissue, but lower percentage of dense calcium. Plaque burden was found to be positively correlated with remodeling index (r = 0.37, P = 0.01) and % fibro-fatty tissue (r = 0.49, P < 0.001) but negatively correlated with % dense calcium (r= −0.31, P = 0.03). The severity of SVG atherosclerosis paralleled with a proportional increase in fibro-fatty tissue. Unstable plaques in SVG were associated with positive remodeling, lipid-rich atheroma, and less calcium deposition, similar to the VH IVUS findings in native coronary arteries.     

Impact of tissue characteristics on luminal narrowing of mild angiographic coronary stenosis: assessment of integrated backscatter intravascular ultrasound

Integrated backscatter intravascular ultrasound (IB-IVUS) is a useful method for analyzing coronary plaque tissue. We evaluated whether tissue composition determined using IB-IVUS is associated with the progression of stenosis in coronary angiography. Sixty-three nontarget coronary lesions in 63 patients with stable angina were evaluated using conventional IVUS and IB-IVUS. IB-IVUS images were analyzed at 1-mm intervals for a length of 10 mm. After calculating the relative areas of the tissue components using the IB-IVUS system, fibrous volume (FV) and lipid volume (LV) were calculated through integration of the slices, after which percentages of per-plaque volume (%FV/PV, %LV/PV) and per-vessel volume (%FV/VV, %LV/VV) were calculated. Progression of coronary stenosis was interpreted from the increase in percent diameter stenosis (%DS) from baseline to the follow-up period (6–9 months) using quantitative coronary angiography. %DS was 24.1 ± 12.8 % at baseline and 23.2 ± 13.7 % at follow-up. Using IB-IVUS, LV was 31.7 ± 10.5 mm³, and %LV/PV and %LV/VV were 45.6 ± 10.3 % and 20.2 ± 6.0 %, respectively. FV, %FV/PV, and %FV/VV were 35.5 ± 12.1 mm³, 52.1 ± 9.5 %, and 23.4 ± 7.1 %, respectively. The change in %DS was ?0.88 ± 7.25 % and correlated closely with %LV/VV (r = 0.27, P = 0.03) on simple regression. Multivariate regression after adjustment for potentially confounding risk factors showed %LV/VV to be correlated independently with changes in %DS (r = 0.42, P = 0.02). Logistic regression analysis after adjusting for confounding coronary risk factors showed LV (odds ratio 1.08; 95 % confidence interval 1.01–1.16; P = 0.03) and %LV/VV (odds ratio 1.13; 95 % confidence interval 1.01–1.28; P = 0.03) to be independent predictors of the progression of angiographic coronary stenosis. Our findings suggest that angiographic luminal narrowing of the coronary artery is likely associated with tissue characteristics. IB-IVUS may provide information about the natural progression of luminal narrowing in coronary stenosis.     

Histological characteristics of plaque with ultrasonic attenuation: a comparison between intravascular ultrasound and histology

OBJECTIVES: Intermediate echogenic plaque without acoustic shadow on intravascular ultrasound (IVUS) imaging has been recognized as fibrous plaque. Such echogenic plaque with ultrasonic attenuation may have higher risk for distal flow disturbance (slow flow/no-reflow) during percutaneous coronary intervention. However, histological evaluation of plaque with ultrasonic attenuation has not been performed. This study evaluated the histological characteristics of plaque with ultrasonic attenuation assessed by IVUS. METHODS: By using IVUS, 36 samples of human cadaveric coronary arterial echogenic plaque (percentage plaque area > 40%) without calcium were selected, and classified into the attenuation group; plaque with ultrasonic attenuation, and the non-attenuation group; plaque without attenuation. These plaques were classified for fibrous, fibrofatty, calcium, and necrotic core areas by histological examination. RESULTS: True fibrous plaque was found in 91.7% of the non-attenuation group, but only 68.0% of the attenuation group (p < 0.01) . On the other hand, the percentage fibrofatty and necrotic core plaque areas in the attenuation group were significant larger than those in the non-attenuation group (fibrofatty: 16.3 +/- 13.8% vs. 2.7 +/- 3.1%, p < 0.01; necrotic core: 13.0 +/- 19.4% vs. 3.9 +/- 8.0%, p = 0.03). CONCLUSIONS. Plaque with ultrasonic attenuation contains more fibrofatty tissue and necrotic core compared to fibrous plaque without attenuation.     

Platelet-Derived Growth Factor Predicts Vulnerable Plaque in Patients with Non-ST Elevation Acute Coronary Syndrome

BackgroundIdentifying a novel biomarker may contribute to detection of vulnerable plaque in patients with non-ST-elevation acute coronary syndrome (NSTE-ACS). The aim of this study was to investigate the relationship between serum platelet-derived growth factor (PDGF) and vulnerable plaque in patients with moderate and low risk of NSTE-ACS.MethodsA total of 65 moderate- and low-risk NSTE-ACS patients with 50–90% coronary stenosis were divided into a vulnerable plaque group (n=46) and a stable plaque group (n=19) according to intravascular ultrasound (IVUS) examinations. Total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and serum PDGF were measured. Plaque characteristics and components were analyzed using gray-scale and iMap-IVUS. Correlation was performed between plaque characteristics and ACS markers. Logistic regression analysis was applied to determine risk factors. Receiver operating characteristic (ROC) curve was used to evaluate the predictive value.ResultsPatients with vulnerable plaque had visible higher levels of TG, LDL-C and PDGF (P < 0.05). There were significant differences in minimal lumen area (MLA), plaque area, plaque burden, fibrotic (FI), clipidic (LI) and necrotic core (NC) between the two groups (P < 0.05). PDGF was weakly correlated with plaque burden (R = 0.428, P < 0.05), as well as moderately correlated with NC (R = 0.669, P < 0.05). Multivariate analysis showed that serum PDGF (OR 4.751, [95% CI 1.534–9.543], P = 0.05) was an independent risk factor of vulnerable plaque. The area under the curve (AUC) was 0.876 (95% CI 0.804–0.948, P=0.001).ConclusionsSerum PDGF could potentially predict vulnerable plaque in moderate and low risk of NSTE-ACS patients.     

Associations of reactive hyperemia index and intravascular ultrasound-assessed coronary plaque morphology in patients with coronary artery disease

Although reactive hyperemia index (RHI) predicts future coronary events, associations with intravascular ultrasound (IVUS)-assessed coronary plaque structure have not been reported. This study therefore investigated associations between RHI and IVUS-assessed coronary plaques. In 362 patients RHI was measured by noninvasive peripheral arterial tonometry and coronary plaque components (fibrous, fibrofatty, necrotic core, and dense calcium) were identified by IVUS in 594 vessel segments of the left anterior descending, circumflex, and/or right coronary arteries. RHI values <1.67 were considered abnormal. Analysis of variance was used to detect independent associations between RHI and plaque composition. Patients with an abnormal RHI had greater plaque burden (41% vs 39% in patients with normal RHI, p = 0.047). Compared to patients with normal RHI, plaque of patients with abnormal RHI had more necrotic core (21% vs 17%, p <0.001) and dense calcium (19% vs 15%, p <0.001) and less fibrous (49% vs 54%, p <0.001) and fibrofatty (11% vs 14%, p = 0.002) tissue. After adjustment for age, gender, cardiovascular risk factors, and drug therapy, abnormal RHI remained significantly associated with fibrous (F ratio 14.79, p <0.001), fibrofatty (F ratio 5.66, p = 0.018), necrotic core (F ratio 14.47, p <0.001), and dense calcium (F ratio 10.80, p = 0.001) volumes. In conclusion, coronary artery plaques of patients with abnormal RHI had a larger proportion of necrotic core and dense calcium. The association of an abnormal RHI with a plaque structure that is more prone to rupture may explain why these patients exhibit a greater risk of coronary events.     

Topological Data Analysis of Coronary Plaques Demonstrates the Natural History of Coronary Atherosclerosis

ObjectivesThis study sought to identify distinct patient groups and their association with outcome based on the patient similarity network using quantitative coronary plaque characteristics from coronary computed tomography angiography (CTA).BackgroundCoronary CTA can noninvasively assess coronary plaques quantitatively.MethodsPatients who underwent 2 coronary CTAs at a minimum of 24 months’ interval were analyzed (n = 1,264). A similarity Mapper network of patients was built by topological data analysis (TDA) based on the whole-heart quantitative coronary plaque analysis on coronary CTA to identify distinct patient groups and their association with outcome.ResultsThree distinct patient groups were identified by TDA, and the patient similarity network by TDA showed a closed loop, demonstrating a continuous trend of coronary plaque progression. Group A had the least coronary plaque amount (median 12.4 mm³ [interquartile range (IQR): 0.0 to 39.6 mm³]) in the entire coronary tree. Group B had a moderate coronary plaque amount (31.7 mm³ [IQR: 0.0 to 127.4 mm³]) with relative enrichment of fibrofatty and necrotic core (32.6% [IQR: 16.7% to 46.2%] and 2.7% [IQR: 0.1% to 6.9%] of the total plaque, respectively) components. Group C had the largest coronary plaque amount (187.0 mm³ [IQR: 96.7 to 306.4 mm³]) and was enriched for dense calcium component (46.8% [IQR: 32.0% to 63.7%] of the total plaque). At follow-up, total plaque volume, fibrous, and dense calcium volumes increased in all groups, but the proportion of fibrofatty component decreased in groups B and C, whereas the necrotic core portion decreased in only group B (all p < 0.05). Group B showed a higher acute coronary syndrome incidence than other groups (0.3% vs. 2.6% vs. 0.6%; p = 0.009) but both group B and C had a higher revascularization incidence than group A (3.1% vs. 15.5% vs. 17.8%; p < 0.001). Incorporating group information from TDA demonstrated increase of model fitness for predicting acute coronary syndrome or revascularization compared with that incorporating clinical risk factors, percentage diameter stenosis, and high-risk plaque features.ConclusionsThe TDA of quantitative whole-heart coronary plaque characteristics on coronary CTA identified distinct patient groups with different plaque dynamics and clinical outcomes. (Progression of AtheRosclerotic PlAque DetermIned by Computed TomoGraphic Angiography Imaging [PARADIGM]; NCT02803411)     

Comparison of virtual histology to intravascular ultrasound of culprit coronary lesions in acute coronary syndrome and target coronary lesions in stable angina pectoris

Coronary plaque composition cannot be assessed accurately using gray-scale intravascular ultrasound (IVUS). Using virtual histology IVUS (VH-IVUS), a comparison of coronary plaque composition between acute coronary syndromes (ACS) and stable angina pectoris (SAP) was performed. Preintervention IVUS of de novo culprit and target lesions was performed in 318 patients (123 with ACS and 195 with SAP). Using VH-IVUS, plaque was characterized as fibrotic, fibrofatty, dense calcium, and necrotic core. VH-IVUS-derived thin-cap fibroatheroma (VH-TCFA) was defined as necrotic core>or=10% of plaque area without overlying fibrous tissue in a plaque burden>or=40%. Lesions were classified into 3 groups: ruptured, VH-TCFA, and non-VH-TCFA plaque. Unstable lesions were defined as either VH-TCFA or ruptured plaque. Compared with patients with SAP, those with ACS had significantly more unstable lesions (89% vs 62%, p<0.001). Planar VH-IVUS analysis at the minimum luminal site and at the largest necrotic core site and volumetric analysis over a 10-mm-long segment centered at the minimum luminal site showed that the percentage of necrotic core was significantly greater and that the percentage of fibrofatty plaque was significantly smaller in patients with ACS. The percentages of fibrotic and fibrofatty plaque areas and volumes were smaller, and the percentages of necrotic core areas and volumes were larger in VH-TCFAs compared with non-TCFAs. Ruptured plaques in VH-IVUS analyses showed intermediate findings between VH-TCFAs and non-VH-TCFAs. In conclusion, culprit lesions in patients with ACS were more unstable and had greater amounts of necrotic core and smaller amounts of fibrofatty plaque compared with target lesions in patients with SAP.     

Ultrasound-assessed non-culprit and culprit coronary vessels differ by age and gender

AIM: To investigate age-and gender-related differences in non-culprit versus culprit coronary vessels assessed with virtual histology intravascular ultrasound (VH-IVUS). METHODS: In 390 patients referred for coronary angiography to a single center (Luzerner Kantonsspital, Switzerland) between May 2007 and January 2011, 691 proximal vessel segments in left anterior descending, circumflex and/or right coronary arteries were imaged by VH-IVUS. Plaque burden and plaque composition(fibrous, fibro-fatty, necrotic core and dense calcium volumes) were analyzed in 3 age tertiles, according to gender and separated for vessels containing non-culprit or culprit lesions. To classify as vessel containing a culprit lesion, the patient had to present with an acute coronary syndrome, and the VH-IVUS had to be performed in a vessel segment containing the culprit lesion according to conventional coronary angiography. RESULTS: In non-culprit vessels the plaque burden increased significantly with aging (in men from 37% ± 12% in the lowest to 46% ± 10% in the highest age tertile, P < 0.001; in women from 30% ± 9% to 40% ± 11%, P < 0.001); men had higher plaque burden than women at any age (P < 0.001 for each of the 3 age tertiles). In culprit vessels of the lowest age tertile, plaque burden was significantly higher than that in non- culprit vessels (in men 48% ± 6%, P < 0.001 as compared to non-culprit vessels; in women 44% ± 18%, P = 0.004 as compared to non-culprit vessels). Plaque burden of culprit vessels did not significantly change during aging (plaque burden in men of the highest age tertile 51% ± 9%, P = 0.523 as compared to lowest age tertile; in women of the highest age tertile 49% ± 8%, P = 0.449 as compared to lowest age tertile). In men, plaque morphology of culprit vessels became increasingly rupture-prone during aging (increasing percentages of necrotic core and dense calcium), whereas plaque morphology in non-culprit vessels was less rupture-prone and remained constant during aging. In women, necrotic core in non-culprit vessels was very low at young age, but increased during aging resulting in a plaque morphology that was very similar to men. Plaque morphology in culprit vessels of young women and men was similar. CONCLUSION: This study provides evidence that age-and gender-related differences in plaque burden and plaque composition significantly depend on whether the vessel contained a non-culprit or culprit lesion.     

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

ObjectiveMurray'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.MethodsIn 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.ResultsPatients 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.ConclusionThis 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.     

Radiomics-Based Precision Phenotyping Identifies Unstable Coronary Plaques From Computed Tomography Angiography

ObjectivesThe aim of this study was to precisely phenotype culprit and nonculprit lesions in myocardial infarction (MI) and lesions in stable coronary artery disease (CAD) using coronary computed tomography angiography (CTA)-based radiomic analysis.BackgroundIt remains debated whether any single coronary atherosclerotic plaque within the vulnerable patient exhibits unique morphology conferring an increased risk of clinical events.MethodsA total of 60 patients with acute MI prospectively underwent coronary CTA before invasive angiography and were matched to 60 patients with stable CAD. For all coronary lesions, high-risk plaque (HRP) characteristics were qualitatively assessed, followed by semiautomated plaque quantification and extraction of 1,103 radiomic features. Machine learning models were built to examine the additive value of radiomic features for discriminating culprit lesions over and above HRP and plaque volumes.ResultsCulprit lesions had higher mean volumes of noncalcified plaque (NCP) and low-density noncalcified plaque (LDNCP) compared with the highest-grade stenosis nonculprits and highest-grade stenosis stable CAD lesions (NCP: 138.1 mm³ vs 110.7 mm³ vs 102.7 mm³; LDNCP: 14.2 mm³ vs 9.8 mm³ vs 8.4 mm³; both P_trend < 0.01). In multivariable linear regression adjusted for NCP and LDNCP volumes, 14.9% (164 of 1,103) of radiomic features were associated with culprits and 9.7% (107 of 1,103) were associated with the highest-grade stenosis nonculprits (critical P < 0.0007) when compared with highest-grade stenosis stable CAD lesions as reference. Hierarchical clustering of significant radiomic features identified 9 unique data clusters (latent phenotypes): 5 contained radiomic features specific to culprits, 1 contained features specific to highest-grade stenosis nonculprits, and 3 contained features associated with either lesion type. Radiomic features provided incremental value for discriminating culprit lesions when added to a machine learning model containing HRP and plaque volumes (area under the receiver-operating characteristic curve 0.86 vs 0.76; P = 0.004).ConclusionsCulprit lesions and highest-grade stenosis nonculprit lesions in MI have distinct radiomic signatures compared with lesions in stable CAD. Within the vulnerable patient may exist individual vulnerable plaques identifiable by coronary CTA-based precision phenotyping.     

Cardiac Computed Tomography Angiography Follow-Up of Resorbable Magnesium Scaffolds

IntroductionAn ancillary advantage of bioresorbable scaffolds is the possibility of non-invasive imaging assessment of the treated coronary segment. Cardiac computed tomography angiography (CCTA) studies of resorbable magnesium scaffolds (RMS) are scarce.MethodsIn this collaborative, international study, nine patients who had an RMS implanted underwent CCTA as part of follow-up assessment. Core-lab blinded quantitative and qualitative assessment was performed by an independent CCTA investigator.ResultsEight studies were amenable for quantitative analysis, and the blinded CT investigator successfully located and evaluated patency of RMS in all cases. The CCTA follow-up in-scaffold percentage diameter stenosis and area stenosis was 22.2% (12.4–30) and 39.1% (0.23–0.50), in keeping with mild in-scaffold late loss and underlying plaque growth. Moreover, a detailed coronary plaque characterization at treated segments was feasible (fibrous plaque in 69.9%, fibrofatty in 17.13%, necrotic in 4.78% and calcium in 5.72%). As in 6 out of 8 cases, the presentation was an acute coronary syndrome, these preliminary results could suggest plaque stabilization and a good coronary vessel healing with RMS.ConclusionNon-invasive, follow-up assessment of RMS with CCTA is feasible. Further CCTA studies for either clinical or research purposes with the present and upcoming generation of resorbable magnesium scaffolds are warranted.     

Serum n-3 to n-6 polyunsaturated fatty acids ratio correlates with coronary plaque vulnerability: an optical coherence tomography study

A low ratio of eicosapentaenoic acid to arachidonic acid (EPA/AA) has been demonstrated to be associated with a higher risk of cardiovascular events. Optical coherence tomography (OCT) is useful for the assessment of coronary plaque vulnerability. The purpose of this study was to evaluate the association between EPA/AA ratio and coronary plaque vulnerability. This study involved 58 patients with stable angina pectoris undergoing percutaneous coronary intervention. OCT image acquisition was performed before the procedure in the culprit lesions. We assessed lipid-rich plaque length and arc, fibrous cap thickness, frequency of thin-cap fibroatheroma (TCFA), thrombus, ruptured plaque, macrophage infiltration, and microvessels using OCT. Patients were divided into two groups according to the median value of serum EPA/AA ratio: a low-EPA/AA group (n = 29, EPA/AA ratio <0.36) and a high-EPA/AA group (n = 29, EPA/AA ratio ≥0.36). In qualitative analyses, TCFA (35.4 vs 6.9 %, P = 0.0095), macrophage infiltration (48.3 vs 13.8 %, P = 0.0045), and microvessels (44.8 vs 10.3 %, P = 0.0033) were more frequently observed in the low-EPA/AA group. In quantitative analyses, the low-EPA/AA group had wider maximum lipid arc (114.0 ± 94.8° vs 56.4 ± 66.0°, P = 0.0097), longer lipid length (4.8 ± 4.5 vs 1.6 ± 2.6 mm, P = 0.0037), and thinner fibrous cap (69.3 ± 28.3 vs 113.3 ± 46.6 μm, P = 0.005) compared with the high-EPA/AA group. EPA/AA ratio was positively correlated with fibrous cap thickness (r = 0.46, P = 0.007). In a multivariate model, an EPA/AA ratio <0.36 was associated with the presence of TCFA (odds ratio 6.41, 95 % confidence interval 1.11–61.91, P = 0.0371). In our detailed OCT analysis, lower EPA/AA ratio was associated with higher vulnerability of coronary plaques to rupture.     

Coronary Atherosclerotic Precursors of Acute Coronary Syndromes

Background

The association of atherosclerotic features with first acute coronary syndromes (ACS) has not accounted for plaque burden.

Glucose transporter 4 and insulin receptor substrate-1 messenger RNA expression in omental and subcutaneous adipose tissue in women

Insulin receptor substrate-1 (IRS-1) and glucose transporter 4 (GLUT4) expression may provide an indirect reflection of the capacity of adipocytes to respond to insulin stimulation. We examined messenger RNA (mRNA) expression of these genes in omental and subcutaneous adipose tissue of women. Paired omental and subcutaneous adipose tissue samples were obtained from 36 women (age, 47 ± 5 years; body mass index, 28.0 ± 5.4 kg/m²) undergoing gynecologic surgeries. Total adiposity and visceral adiposity were assessed by dual-energy x-ray absorptiometry and computed tomography. The GLUT4 and IRS-1 mRNA expression levels were both significantly higher in subcutaneous compared with omental adipose tissue. A negative correlation was observed between body fat percentage and subcutaneous adipose tissue GLUT4 (r = −0.39, P < .05) and IRS-1 (r = −0.30, P < .08) mRNA abundance. However, in omental fat, only GLUT4 mRNA was inversely associated with body fat percentage (r = −0.53, P < .001). Moreover, the homeostasis model assessment of insulin resistance index was associated with mRNA expression of subcutaneous GLUT4 (r = −0.56, P < .001), subcutaneous IRS-1 (r = −0.51, P < .01), and omental GLUT4 (r = −0.54, P < .001), but not omental IRS-1. Interestingly, plasma adiponectin was only associated with subcutaneous GLUT4 (r = 0.48, P < .01) and IRS-1 (r = 0.48, P < .05) mRNA expression. The GLUT4 protein, unlike mRNA expression, was higher in omental than in subcutaneous adipose tissue. However, abdominal obesity-related differences in protein or mRNA expression were similar. Omental IRS-1 expression was low and unaffected by visceral obesity. In contrast, omental and subcutaneous GLUT4 as well as subcutaneous IRS-1 were reduced in visceral obesity. This divergent pattern of expression may reflect a lower capacity of omental adipose tissue to respond to insulin stimulation at all adiposity levels.     

Acylation-stimulating protein precursor proteins in adipose tissue in human obesity

Recent reports have suggested a link between acylation-stimulating protein (ASP) and complement C3 with obesity, insulin resistance, coronary artery disease, and hyperlipidemia. Our aim was to examine the mRNA expression of C3 and other factors related to ASP production (such as factor B and adipsin) in adipose tissue. The influence of gender and obesity was examined in subcutaneous (SC) and omental (OM) tissues from 16 males and 16 females with body mass index (BMI) from 20 to 54 kg/m². The results demonstrate that factor B mRNA expression is higher in males than females in both SC and OM tissues. In female SC tissue, C3 and adipsin mRNA decrease with increasing BMI (r = 0.557, P = .025 and r = 0.717 P = .002, respectively), with no change in factor B. By contrast, in males there was a pronounced increase in C3, adipsin, and factor B in OM tissue with increasing BMI (r = 0.759 P = .001, r = 0.650 P = .006, and r = 0.568 P = .022, respectively). Of note, however, in both men and women there was a marked increase in the OM/SC ratio of C3 and adipsin with increasing BMI. These results suggest that in female SC adipose tissue, there is downregulation of factors related to ASP production in obesity, perhaps to limit further expansion of adipose tissue. In males, there is increased expression in OM tissue. In addition, relative OM/SC expression increases with obesity and these changes may contribute to the development of visceral adipose tissue.     

血管内超声及虚拟组织学评估冠状动脉血管重构与斑块成分的关系

目的应用血管内超声及虚拟组织学技术检测冠心病患者的冠状动脉重构与斑块成分之间的关系。方法对41例冠心病患者行血管内超声及虚拟组织学检查,根据其重构指数分为正性重构组(n=19)及负性重构组(n=22),检测并比较两组的斑块负荷、血管面积、管腔面积以及斑块成分等。结果与负性重构组比较,正性重构组最小管腔处血管面积(17.95±4.25 mm~2比11.44±2.13 mm~2)、管腔面积(6.02±1.85 mm~2比4.98±1.06 mm~2)、斑块负荷(63.83%±7.89%比63.83%±7.89%)均显著增大(P0.05)。虚拟组织学显示正性重构组比负性重构组坏死成分比例增加(30.38%±9.33%比17.19%±11.31%,P=0.001)、纤维成分比例减少(44.61%±14.93%比61.08%±14.81%,P=0.002),钙化和纤维脂质比例无明显差异(P0.05)。重构指数与坏死成分比例呈正相关(r=0.373,P=0.023)。结论冠状动脉的正性重构伴随着坏死核心增加,正性重构可能是冠状动脉斑块不稳定的表现。     

Coronary plaque morphology using virtual histology-intravascular ultrasound analysis in hemodialysis patients

Most dialysis patients have coronary artery disease at the initiation of dialysis therapy and these patients also have marked vascular calcification. Virtual histology-intravascular ultrasound (VH-IVUS) provides coronary tissue maps that are color coded by four major plaque components and facilitate the characterization of coronary plaque composition in vivo. The aim of this study was to identify coronary plaque characteristics in dialysis patients using VH-IVUS. Twenty-three patients with coronary artery disease were included in this study. Of these, 12 patients had normal renal function or mild renal insufficiency (control group) and 11 patients were receiving maintenance dialysis therapy (hemodialysis group). We performed coronary angiography and VH-IVUS analysis on culprit lesions of all patients in the study. The result of VH-IVUS analysis showed that the hemodialysis group had a greater plaque volume, lower percentage of fibrous plaque, and higher percentage of dense calcium plaque compared with the control group. In addition, the serum phosphate levels were significantly associated with the percentage of necrotic core and dense calcium plaque in all study patients. Our findings suggest that the amount of necrotic core and dense calcium plaques increase significantly in hemodialysis patients, and that disordered mineral metabolism may be associated with coronary plaque morphology.     

Association of Tube Voltage With Plaque Composition on Coronary CT Angiography: Results From PARADIGM Registry

ObjectivesThis study sought to investigate the impact of low tube voltage scanning heterogeneity of coronary luminal attenuation on plaque quantification and characterization with coronary computed tomography angiography (CCTA).BackgroundThe impact of low tube voltage and coronary luminal attenuation on quantitative coronary plaque remains uncertain.MethodsA total of 1,236 consecutive patients (age: 60 ± 9 years; 41% female) who underwent serial CCTA at an interval of ≥2 years were included from an international registry. Patients with prior revascularization or nonanalyzable coronary CTAs were excluded. Total coronary plaque volume was assessed and subclassified based on specific Hounsfield unit (HU) threshold: necrotic core, fibrofatty plaque, and fibrous plaque and dense calcium. Luminal attenuation was measured in the aorta.ResultsWith increasing luminal HU (<350, 350-500, and >500 HU), percent calcified plaque was increased (16%, 27%, and 40% in the median; P < 0.001), and fibrofatty plaque (26%, 13%, and 4%; P < 0.001) and necrotic core (1.6%, 0.3%, and 0.0%; P < 0.001) were decreased. Higher tube voltage scanning (80, 100, and 120 kV) resulted in decreasing luminal attenuation (689 ± 135, 497 ± 89, and 391 ± 73 HU; P < 0.001) and calcified plaque volume (59%, 34%, and 23%; P < 0.001) and increased fibrofatty plaque (3%, 9%, and 18%; P < 0.001) and necrotic core (0.2%, 0.1%, and 0.6%; P < 0.001). Mediation analysis showed that the impact of 100 kV on plaque composition, compared with 120 kV, was primarily caused by an indirect effect through blood pool attenuation. Tube voltage scanning of 80 kV maintained a direct effect on fibrofatty plaque and necrotic core in addition to an indirect effect through the luminal attenuation.ConclusionsLow tube voltage usage affected plaque morphology, mainly through an increase in luminal HU with a resultant increase in calcified plaque and a reduction in fibrofatty and necrotic core. These findings should be considered as CCTA-based plaque measures are being used to guide medical management and, in particular, when being used as a measure of treatment response. (Progression of Atherosclerotic Plaque Determined by Computed Tomographic Angiography Imaging [PARADIGM]; NCT02803411)