Relation between thoracic aortic inflammation and features of plaque vulnerability in the coronary tree in patients with non-ST-segment elevation acute coronary syndrome undergoing percutaneous coronary intervention. An FDG-positron emission tomography and optical coherence tomography study

Unravelling the role of macrophages in cardiovascular inflammation through imaging: a state-of-the-art review

Cardiovascular disease remains the leading cause of death and disability for patients across the world. Our understanding of atherosclerosis as a primary cholesterol issue has diversified, with a significant dysregulated inflammatory component that largely remains untreated and continues to drive persistent cardiovascular risk. Macrophages are central to atherosclerotic inflammation, and they exist along a functional spectrum between pro-inflammatory and anti-inflammatory extremes. Recent clinical trials have demonstrated a reduction in major cardiovascular events with some, but not all, anti-inflammatory therapies. The recent addition of colchicine to societal guidelines for the prevention of recurrent cardiovascular events in high-risk patients with chronic coronary syndromes highlights the real-world utility of this class of therapies. A highly targeted approach to modification of interleukin-1-dependent pathways shows promise with several novel agents in development, although excessive immunosuppression and resulting serious infection have proven a barrier to implementation into clinical practice. Current risk stratification tools to identify high-risk patients for secondary prevention are either inadequately robust or prohibitively expensive and invasive. A non-invasive and relatively inexpensive method to identify patients who will benefit most from novel anti-inflammatory therapies is required, a role likely to be fulfilled by functional imaging methods. This review article outlines our current understanding of the inflammatory biology of atherosclerosis, upcoming therapies and recent landmark clinical trials, imaging modalities (both invasive and non-invasive) and the current landscape surrounding functional imaging including through targeted nuclear and nanobody tracer development and their application.

Pattern of arterial inflammation and inflammatory markers in people living with HIV compared with uninfected people

STUDY DESIGN

To compare arterial inflammation (AI) between people living with HIV (PLWH) and uninfected people as assessed by 18F-Fluorodeoxyglucose (18F-FDG)-positron emission tomography (PET).

METHODS

We prospectively enrolled 20 PLWH and 20 uninfected people with no known cardiovascular disease and at least 3 traditional cardiovascular risk factors. All patients underwent 18F-FDG-PET/computed tomography (CT) of the thorax and neck. Biomarkers linked to inflammation and atherosclerosis were also determined. The primary outcome was AI in ascending aorta (AA) measured as mean maximum target-to-background ratio (TBRmax). The independent relationships between HIV status and both TBRmax and biomarkers were evaluated by multivariable linear regression adjusted for body mass index, creatinine, statin therapy, and atherosclerotic cardiovascular 10-year estimated risk (ASCVD).

RESULTS

Unadjusted mean TBRmax in AA was slightly higher but not statistically different (P = .18) in PLWH (2.07; IQR 1.97, 2.32]) than uninfected people (2.01; IQR 1.85, 2.16]). On multivariable analysis, PLWH had an independent risk of increased mean log-TBRmax in AA (coef = 0.12; 95%CI 0.01,0.22; P = .032). HIV infection was independently associated with higher values of interleukin-10 (coef = 0.83; 95%CI 0.34, 1.32; P = .001), interferon-γ (coef. = 0.90; 95%CI 0.32, 1.47; P = .003), and vascular cell adhesion molecule-1 (VCAM-1) (coef. = 0.75; 95%CI: 0.42, 1.08, P < .001).

CONCLUSIONS

In patients with high cardiovascular risk, HIV status was an independent predictor of increased TBRmax in AA. PLWH also had an increased independent risk of IFN-γ, IL-10, and VCAM-1 levels.

Optical coherence tomography assessment of macrophages accumulation in non-ST-segment elevation acute coronary syndromes

AIMS

To investigate in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) the prevalence and the features of optical coherence tomography (OCT)-detected macrophages accumulation in culprit plaques as compared with nonculprit plaques (NCP).

METHODS

The study is a post-hoc analysis of a prospective study aimed at evaluating the relationship between aortic inflammation as assessed by F-fluorodeoxyglucose-PET and features of coronary plaque vulnerability as assessed by OCT. We enrolled 32 patients with first NSTE-ACS who successfully underwent three-vessel OCT.

RESULTS

The median age was 65 (54-72) years and 27 patients (84%) were men. Culprit plaques were clinically defined. Overall, the rate of lipid plaques and lipid plaques containing macrophages were 6.4 and 4.2 per patient, respectively. Culprit plaques had a smaller minimal luminal area, a higher extension of lipid component and a thinner fibrous cap than NCPs. Macrophages accumulations were more likely found in culprit plaque (84 vs. 61%, P = 0.015) in which they had also a higher circumferential extension. On univariable analysis, macrophages accumulation extension had a higher association with culprit plaques (odds ratio = 4.42; 95% confidence interval; 2.54-9.15, P < 0.001) than the mere presence of macrophages accumulation (odds ratio = 3.36; 95% confidence interval; 1.30-8.66, P = 0.012). Culprit plaques with thrombus had a lower distance between macrophages accumulation and the luminal surface than culprit plaque with no thrombus (0.06 vs. 0.1 mm; P = 0.04).

CONCLUSION

In patients with NSTE-ACS, macrophages accumulations are more likely present in culprit plaque in which they disclose also a greater extension compared with those observed in NCP. The distance between macrophages accumulation and the luminal surface is lower in thrombotic culprit plaque than that in nonthrombotic culprit plaque.

Cardiovascular Imaging Techniques for Detection of Vulnerable Plaques

Various cardiovascular imaging techniques were developed for the detection of vulnerable atherosclerotic plaques, hoping to be able to predict a cardiovascular event. Plaque vulnerability results from compound pathophysiological mechanisms that lead to structural and morphological changes in lesions. The aim of this review is to present the most recent techniques for the assessment of vulnerable coronary plaques such as cardiac computed tomography angiography (CCTA), optical coherence tomography, or virtual histology intravascular ultra-sound, based on literature data from the last 3 years. CCTA permits direct visualization of the intravascular lumen, together with characterization of the arterial wall. Recent studies maintain that low-attenuation plaques, spotty calcifications, positive vessel remodeling, and the napkin-ring sign are considered main markers of plaque vulnerability and instability. Emerging analytical techniques, such as machine learning or radiomics, will probably demonstrate useful as an auxiliary diagnostic tool for vulnerable plaque detection. The data from the two imaging techniques together provide useful information, especially in patients undergoing a PCI procedure for an acute coronary syndrome. Invasive and noninvasive imaging techniques are able to deliver a large amount of scientific data to assess vulnerable coronary atheromatous plaques. Recent studies demonstrated that information defined by the two techniques is complementary, and using both methods is essential for adequate diagnosis, therapeutic strategy, and prognostic assessment.

The complex interplay among atherosclerosis, inflammation, and degeneration in ascending thoracic aortic aneurysms

OBJECTIVE

To assess the histopathological findings of a large series of ascending thoracic aortic aneurysm (TAA) surgical specimens applying the updated classification on noninflammatory degenerative and inflammatory aortic diseases proposed by the Association for European Cardiovascular Pathology and the Society for Cardiovascular Pathology clinicopathological correlations.

METHODS

A total of 255 patients surgically treated for ascending TAA were enrolled. Surgical ascending aorta specimens were examined.

RESULTS

The histopathological substrate of ascending TAAs was mainly degenerative (67.5%), but with a remarkable prevalence of atherosclerotic lesions (18.8%) and aortitis (13.7%). Degenerative patients more frequently had bicuspid aortic valve (37.2%; P = .002). Patients in the atherosclerotic group were older (median age, 69 years; P < .001), more often with a history of hypertension (87.5%; P = .059), hypercholesterolemia (75%; P = .019), diabetes (16.6%; P = .054), current smoking (22.9%; P = .066), and a history of coronary artery disease (18.7%; P = .063). Patients with aortitis represented the older group (median age, 75 years, P < .001), were mostly females (68.6%; P < .001), and had a larger ascending aorta diameter (median, 56 mm; P < .001). Both patients with atherosclerosis and aortitis presented a higher incidence of concomitant abdominal aortic aneurysm (20.8% and 22.8%, respectively; P < .001).

CONCLUSIONS

Although degenerative histopathology is the most frequent substrate in ascending TAA, atherosclerosis and inflammation significantly contribute to the development of chronic aortic thoracic disease.