Comparison between integrated backscatter intravascular ultrasound and 64-slice multi-detector row computed tomography for tissue characterization and volumetric assessment of coronary plaques

Insulin resistance is associated with high-risk coronary artery plaque composition in asymptomatic men between 65 and 75 years and no diabetes: A DANCAVAS cross-sectional sub-study

BACKGROUND AND AIMS

Insulin resistance (IR) and pre-diabetes are associated with an increased risk of cardiovascular disease (CVD). We aimed to investigate vulnerable plaque composition in relation to IR and pre-diabetes in asymptomatic non-diabetic men.

METHODS

All participants underwent a contrast-enhanced coronary computed tomography angiography (CCTA) to evaluate coronary artery plaque burden and plaque composition (necrotic core, dense calcium, fibrotic and fibrous-fatty volume). Homeostasis model assessment of IR (HOMA-IR) was used, and participants were stratified into tertiles. Participants underwent a standard oral glucose tolerance test (OGTT) and were categorized into 2 groups (normal glucose tolerance (NGT) or pre-diabetes). A multivariable linear regression model was used to evaluate the association between vulnerable plaque composition and IR or glycemic group.

RESULTS

Four-hundred-and-fifty non-diabetic men without known CAD were included. The mean age was 70 ± 3 years. Participants in the higher HOMA-IR tertile (H-IR) had higher median necrotic plaque volume compared to the lower HOMA-IR tertile (L-IR) (18.2 vs. 11.0 mm3, p = 0.02). H-IR tertile (β 0.37 [95% CI 0.10-0.65], p = 0.008), pack-years (β 0.07 [95% CI 0.007-0.14], p = 0.03) and total atheroma volume (TAV) (β 0.47 [95% CI 0.36-0.57], p < 0.001) remained associated with necrotic plaque volume in the multivariable linear regression model.

CONCLUSIONS

IR was associated with necrotic plaque volume in asymptomatic men without diabetes. Thus, even in asymptomatic men without diabetes, IR seems to have an incremental effect on necrotic plaque volume and vulnerable plaque composition.

[Computed Tomography Coronary Angiography Possibilities in "High Risk" Plaque Identification in Patients with non-ST-Elevation Acute Coronary Syndrome: Comparison with Intravascular Ultrasound]

Aim      To evaluate structural characteristics of atherosclerotic plaques (ASP) by coronary computed tomography arteriography (CCTA) and intravascular ultrasound (IVUS).Material and methods  This study included 37 patients with acute coronary syndrome (ACS). 64-detector-row CCTA, coronarography, and grayscale IVUS were performed prior to coronary stenting. The ASP length and burden, remodeling index (RI), and known CT signs of unstable ASP (presence of dot calcification, positive remodeling of the artery in the ASP area, irregular plaque contour, presence of a peripheral high-density ring and a low-density patch in the ASP). The ASP type and signs of rupture or thrombosis were determined by IVUS.Results The IVUS study revealed 45 unstable ASP (UASP), including 25 UASP with rupture and 20 thin-cap fibroatheromas (TCFA), and 13 stable ASP (SASP). No significant differences were found between distribution of TCFA and ASP with rupture among symptom-associated plaques (SAP, n=28) and non-symptom-associated plaques (NSAP, n=30). They were found in 82.1 and 73.3 % of cases, respectively (p&gt;0.05), which indicated generalization of the ASP destabilization process in the coronary circulation. However, the incidence of mural thrombus was higher for SAP (53.5 and 16.6 % of ASP, respectively; p&lt;0.001). There was no difference between UASP and SASP in the incidence of qualitative ASP characteristics or in values of quantitative ASP characteristics, including known signs of instability, except for the irregular contour, which was observed in 92.9 % of UASP and 46.1 % of SASP (p=0.0007), and patches with X-ray density ≤46 HU, which were detected in 83.3 % of UASP and 46.1 % of SASP (р=0.01). The presence of these CT criteria 11- and 7-fold increased the likelihood of unstable ASP (odd ratio (OR), 11.1 at 95 % confidence interval (CI), from 2.24 to 55.33 and OR, 7.0 at 95 % CI, from 5.63 to 8.37 for the former and the latter criterion, respectively).Conclusion      According to IVUS data, two X-ray signs are most characteristic for UASP, the irregular contour and a patch with X-ray density ≤46 HU. The presence of these signs 11- and 7-fold, respectively, increases the likelihood of unstable ASP.

Effect of Vascepa (icosapent ethyl) on progression of coronary atherosclerosis in patients with elevated triglycerides (200-499 mg/dL) on statin therapy: Rationale and design of the EVAPORATE study

Despite reducing progression and promoting regression of coronary atherosclerosis, statin therapy does not fully address residual cardiovascular (CV) risk. High‐purity eicosapentaenoic acid (EPA) added to a statin has been shown to reduce CV events and induce regression of coronary atherosclerosis in imaging studies; however, data are from Japanese populations without high triglyceride (TG) levels and baseline EPA serum levels greater than those in North American populations. Icosapent ethyl is a high‐purity prescription EPA ethyl ester approved at 4 g/d as an adjunct to diet to reduce TG levels in adults with TG levels >499 mg/dL. The objective of the randomized, double‐blind, placebo‐controlled EVAPORATE study is to evaluate the effects of icosapent ethyl 4 g/d on atherosclerotic plaque in a North American population of statin‐treated patients with coronary atherosclerosis, TG levels of 200 to 499 mg/dL, and low‐density lipoprotein cholesterol levels of 40 to 115 mg/dL. The primary endpoint is change in low‐attenuation plaque volume measured by multidetector computed tomography angiography. Secondary endpoints include incident plaque rates; quantitative changes in different plaque types and morphology; changes in markers of inflammation, lipids, and lipoproteins; and the relationship between these changes and plaque burden and/or plaque vulnerability. Approximately 80 patients will be followed for 9 to 18 months. The clinical implications of icosapent ethyl 4 g/d treatment added to statin therapy on CV endpoints are being evaluated in the large CV outcomes study REDUCE‐IT. EVAPORATE will provide important imaging‐derived data that may add relevance to the clinically derived outcomes from REDUCE‐IT.

Assessment of vulnerable atherosclerotic and fibrotic plaques in coronary arteries using (68)Ga-DOTATATE PET/CT

Activated macrophages which express somatostatin receptor-2 (SSTR-2) play a vital role in rupture of the vulnerable atherosclerotic plaques, which result in death. (68)Ga-DOTATATE binds to somatostatin receptors 2, and therefore, can serve as potential radiotracer to detect atherosclerotic plaques. The purpose of this study was to generate preliminary data with this agent in vulnerable or fibrotic atherosclerotic plaques in the coronary arteries. We evaluated a total of 44 patients with neuroendocrine tumors (NET) who underwent (68)Ga-DOTATATE PET/CT. In each subject, 7 segments in the coronary arteries were assessed, maximum SUV values and target-to-background ratios (TBRs) were calculated. The lesions detected by CT (a total of 308) were divided into 3 groups based on the Hounsfield unites (HU), and of which, 131 with HU less than 70 were classified as being normal (Control Group), 129 with HU 71-188 as fibrotic plaques (Group 2), and. 48 lesions with HU more than 188 as atherosclerotic plaques (Group 3). The mean TBR value in the normal group was 1.345 ± 0.58 while the mean TBR value in the fibrotic plaque group was 1.752 ± 1.50 (p 0.0043) and in atherosclerotic plaques group was (2.043 ± 1.76, p<0.0001). There was a significant correlation (p=0.0026) between (68)Ga-DOTATATE uptake and the progression to formation of atherosclerotic plaques, based on HU. In patients with neuroendocrine tumors, (68)Ga-DOTATATE PET/CT showed significantly increased uptake in the fibrotic and vulnerable atherosclerotic plaques compared to normal coronary arteries suggesting a potential role of this tracer for molecular assessment of coronary artery disease in this population.

Echocardiographic integrated backscatter for detecting progression and regression of aortic valve calcifications in rats

Background

Calcification is an independent predictor of mortality in calcific aortic valve disease (CAVD). The aim of this study was to evaluate the use of non-invasive, non-ionizing echocardiographic calibrated integrated backscatter (cIB) for monitoring progression and subsequent regression of aortic valvular calcifications in a rat model of reversible renal failure with CAVD, compared to histology.

Methods

28 male Wistar rats were prospectively followed during 21 weeks. Group 1 (N=14) was fed with a 0.5% adenine diet for 9 weeks to induce renal failure and CAVD. Group 2 (N=14) received a standard diet. At week 9, six animals of each group were killed. The remaining animals of group 1 (N=8) and group 2 (N=8) were kept on a standard diet for an additional 12 weeks. cIB of the aortic valve was calculated at baseline, 9 and 21 weeks, followed by measurement of the calcified area (Ca Area) on histology.

Results

At week 9, cIB values and Ca Area of the aortic valve were significantly increased in the adenine-fed rats compared to baseline and controls. After 12 weeks of adenine diet cessation, cIB values and Ca Area of group 1 decreased compared to week 9, while there was no longer a significant difference compared to age-matched controls of group 2.

Conclusions

cIB is a non-invasive tool allowing quantitative monitoring of CAVD progression and regression in a rat model of reversible renal failure, as validated by comparison with histology. This technique might become useful for assessing CAVD during targeted therapy.