Use of coronarycomputed tomography for cardiovascular risk assessment in immune-mediated inflammatory diseases

Immune-mediated inflammatory diseases (IMIDs) are recognised risk factors for accelerated atherosclerotic cardiovascular disease (CVD), particularly in younger individuals and women who lack traditional CVD risk factors. Reflective of the critical role that inflammation plays in the formation, progression and rupture of atherosclerotic plaques, research into immune mechanisms of CVD has led to the identification of a range of therapeutic targets that are the subject of ongoing clinical trials. Several key inflammatory pathways implicated in the pathogenesis of atherosclerosis are targeted in people with IMIDs. However, cardiovascular risk continues to be systematically underestimated by conventional risk assessment tools in the IMID population, resulting in considerable excess CVD burden and mortality. Hence, there is a pressing need to improve methods for CVD risk-stratification among patients with IMIDs, to better guide the use of statins and other prognostic interventions. CT coronary angiography (CTCA) is the current first-line investigation for diagnosing and assessing the severity of coronary atherosclerosis in many individuals with suspected angina. Whether CTCA is also useful in the general population for reclassifying asymptomatic individuals and improving long-term prognosis remains unknown. However, in the context of IMIDs, it is conceivable that the information provided by CTCA, including state-of-the-art assessments of coronary plaque, could be an important clinical adjunct in this high-risk patient population. This narrative review discusses the current literature about the use of coronary CT for CVD risk-stratification in three of the most common IMIDs including rheumatoid arthritis, psoriasis and systemic lupus erythematosus.

CT pericoronary adipose tissue density predicts coronary allograft vasculopathy and adverse clinical outcomes after cardiac transplantation

AIMS

To assess pericoronary adipose tissue (PCAT) density on Coronary Computed Tomography Angiography (CCTA) as a marker of inflammatory disease activity in coronary allograft vasculopathy (CAV).

METHODS AND RESULTS

PCAT density, lesion volumes, and total vessel volume-to-myocardial mass ratio (V/M) were retrospectively measured in 126 CCTAs from 94 heart transplant patients (mean age 49 [SD 14.5] years, 40% female) who underwent imaging between 2010 to 2021; age and sex-matched controls; and patients with atherosclerosis. PCAT density was higher in transplant patients with CAV (n = 40; -73.0 HU [SD 9.3]) than without CAV (n = 86; -77.9 HU [SD 8.2]), and controls (n = 12; -86.2 HU [SD 5.4]), p < 0.01 for both. Unlike patients with atherosclerotic coronary artery disease (n = 32), CAV lesions were predominantly non-calcified, comprised of mostly fibrous or fibrofatty tissue. V/M was lower in patients with CAV than without (32.4 mm3/g [SD 9.7] vs. 41.4 mm3/g [SD 12.3], p < 0.0001). PCAT density and V/M improved the ability to predict CAV from AUC 0.75 to 0.85 when added to donor age and donor hypertension status (p < 0.0001). PCAT density above -66 HU was associated with a greater incidence of all-cause mortality (OR 18.0 [95%CI 3.25-99.6], p < 0.01) and the composite endpoint of death, CAV progression, acute rejection, and coronary revascularization (OR 7.47 [95%CI 1.8-31.6], p = 0.01) over 5.3 (SD 2.1) years.

CONCLUSIONS

Heart transplant patients with CAV have higher PCAT density and lower V/M than those without. Increased PCAT density is associated with adverse clinical outcomes. These CCTA metrics could be useful for diagnosis and monitoring of CAV severity.

Somatostatin Receptor PET/MR Imaging of Inflammation in Patients With Large Vessel Vasculitis and Atherosclerosis

BACKGROUND

Assessing inflammatory disease activity in large vessel vasculitis (LVV) can be challenging by conventional measures.

OBJECTIVES

We aimed to investigate somatostatin receptor 2 (SST2) as a novel inflammation-specific molecular imaging target in LVV.

METHODS

In a prospective, observational cohort study, in vivo arterial SST2 expression was assessed by positron emission tomography/magnetic resonance imaging (PET/MRI) using 68Ga-DOTATATE and 18F-FET-βAG-TOCA. Ex vivo mapping of the imaging target was performed using immunofluorescence microscopy; imaging mass cytometry; and bulk, single-cell, and single-nucleus RNA sequencing.

RESULTS

Sixty-one participants (LVV: n = 27; recent atherosclerotic myocardial infarction of ≤2 weeks: n = 25; control subjects with an oncologic indication for imaging: n = 9) were included. Index vessel SST2 maximum tissue-to-blood ratio was 61.8% (P < 0.0001) higher in active/grumbling LVV than inactive LVV and 34.6% (P = 0.0002) higher than myocardial infarction, with good diagnostic accuracy (area under the curve: ≥0.86; P < 0.001 for both). Arterial SST2 signal was not elevated in any of the control subjects. SST2 PET/MRI was generally consistent with 18F-fluorodeoxyglucose PET/computed tomography imaging in LVV patients with contemporaneous clinical scans but with very low background signal in the brain and heart, allowing for unimpeded assessment of nearby coronary, myocardial, and intracranial artery involvement. Clinically effective treatment for LVV was associated with a 0.49 ± 0.24 (standard error of the mean [SEM]) (P = 0.04; 22.3%) reduction in the SST2 maximum tissue-to-blood ratio after 9.3 ± 3.2 months. SST2 expression was localized to macrophages, pericytes, and perivascular adipocytes in vasculitis specimens, with specific receptor binding confirmed by autoradiography. SSTR2-expressing macrophages coexpressed proinflammatory markers.

CONCLUSIONS

SST2 PET/MRI holds major promise for diagnosis and therapeutic monitoring in LVV. (PET Imaging of Giant Cell and Takayasu Arteritis [PITA], NCT04071691; Residual Inflammation and Plaque Progression Long-Term Evaluation [RIPPLE], NCT04073810).

Imaging of post-infarct myocardial inflammation with 68Ga-DOTATATE PET/MRI

Background

After myocardial infarction (MI), inflammation and its resolution modulate the extent of myocardial damage. 68Ga-DOTATATE is a PET tracer that binds to somatostatin receptor 2 (SST2), which is up-regulated in pro-inflammatory macrophages [1].

Purpose

We investigated 68Ga-DOTATATE PET/MRI for quantifying post-infarct myocardial inflammation.

Methods

In this prospective observational cohort study, participants with MI underwent 68Ga-DOTATATE PET/MRI at baseline (t0: &lt;2 weeks post-MI) and 3 months (t3M). Patients with prior MI, heart failure, coronary revascularisation, or contraindication to PET/MRI, were excluded. Blood samples were taken at the time of imaging for high sensitivity CRP (hsCRP), high sensitivity troponin I (hsTnI), NTproBNP and peripheral blood monocyte subset counts measured by mass cytometry. 68Ga-DOTATATE maximum Standardised Uptake Values (SUV) and Tissue-to-Background Ratios (TBR) adjusted for blood pool activity were compared in the infarct defined by late gadolinium enhancement (LGE) MRI to remote myocardium at t0 and t3M.

Results

Thirty-two patients (mean age 59 [SD 9] years; 26 [81%] male and 6 [19%] female), comprised of 18 (56%) patients with ST elevation MI and 14 (44%) with non-ST elevation MI, were enrolled. Mean peak troponin was 16,953ng/L (range 408 to &gt;25,000ng/L), and 16 (52%) patients had left ventricular impairment (ejection fraction &lt;50%).

68Ga-DOTATATE PET signal co-localised with myocardial LGE and focal oedema (arrows) on T2-weighted MRI (Fig. 1; asterisk: culprit artery) and had excellent ability to discriminate infarct from remote regions (t0: infarct SUV 2.41 vs. remote 1.58, p&lt;0.0001; t0: infarct TBR 5.08 vs. 3.35, p&lt;0.0001; Fig. 2a).

At 100 (SD 13) days after MI (n=23 patients), residual 68Ga-DOTATATE uptake in the infarct remained higher than remote myocardium (t3M: infarct SUV 1.88 vs. remote 1.27, p&lt;0.0001; t3M: infarct TBR 3.96 vs. remote 2.73, p&lt;0.0001), but was reduced compared to baseline (SUV −22%, p&lt;0.0001; TBR −22%, p=0.002; Fig. 2b).

Reduction in infarct 68Ga-DOTATATE uptake was consistent with overall decreases in hsCRP (2.16 vs. 8.76 mg/L), hsTnI (19 vs. 1365 ng/L) and NTproBNP (372 vs. 959 pg/mL) at t3M vs. t0 (n=23, all p&lt;0.05). Focal oedema on MRI was resolved in 17 (74%) patients at t3M. Infarct-to-remote TBR ratio at t0 was correlated with hsTnI (r=0.35, p&lt;0.05). At t3M (n=9 samples) vs t0 (n=20 samples), there was a reduction in % classical-to-non-classical ratio of peripheral monocytes (mean 6.5 [SD 3.8] vs. 14.4 [SD 11.2], p=0.005).

Conclusions

This is the first prospective study of serial 68Ga-DOTATATE PET/MRI in patients after MI. Here we show that 68Ga-DOTATATE tracks resolving myocardial inflammation. Ongoing work as part of this study seeks to confirm the cellular origin of infarct-related 68Ga-DOTATATE PET signal and SST2 expression within inflamed myocardial tissue, and test its longer-term association with ischaemic myocardial remodelling.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Wellcome TrustBritish Heart Foundation

Trans-Myocardial Blood Interleukin-6 Levels Relate to Intracoronary Imaging-Defined Features of Plaque Vulnerability and Predict Procedure-Induced Myocardial Infarction

BACKGROUND

Intravascular imaging has defined various vulnerable plaque (VP) phenotypes that predict future clinical events. Atherosclerosis is an inflammatory process and inflammation, measured by systemic biomarkers can also predict events and anti-inflammatory therapy is beneficial. We were interested to assess the relationship between plaque phenotypes and key inflammatory biomarkers, measured close to the coronary.

METHODS

Ninety-two patients scheduled for elective percutaneous coronary intervention (PCI) underwent virtual histology intravascular ultrasound, optical coherence tomography, pressure wire and blood sampling from the guide catheter (GC), coronary sinus (CS) to determine trans-myocardial gradient (TMG = CS-GC) and from peripheral blood. Procedure related troponin release was assessed at 6-hours post-PCI from peripheral venous blood. Biomarker data were analysed and compared with coronary data.

RESULTS

Interleukin (IL)-6 was associated with increased levels of tumour necrosis factor (TNF)-α and C-reactive protein (CRP) and the pre-PCI IL-6 TMG correlated with plaque features of vulnerability: plaque burden - PB (r = 0.253, p = 0.04) and minimal lumen area - MLA (r = -0.438, p = 0.007), although no relationship existed for thin-capped fibroatheroma defined by either imaging modality. Peripheral IL-6 levels had no correlation with post PCI troponin, although the pre-PCI IL-6 TMG was related (r = 0.334, p = 0.006), as was PB (r = 0.27, p = 0.029).

CONCLUSION

IL-6 TMG pre-PCI correlates with plaque burden and MLA that have been shown to predict future clinical events and is correlated with post-PCI troponin release. These associations were not apparent from peripheral blood and suggest that local coronary biomarker signatures may help further define vulnerability and risk.

Preoperative Atrial Fibrillation is associated with long-term morTality in patients undergoing suRgical AortiC valvE Replacement

INTRODUCTION

Atrial fibrillation (AF) is frequent after any cardiac surgery, but evidence suggests it may have no significant impact on survival if sinus rhythm (SR) is effectively restored early after the onset of the arrhythmia. In contrast, management of preoperative AF is often overlooked during or after cardiac surgery despite several proposed protocols. This study sought to evaluate the impact of preoperative AF on mortality in patients undergoing isolated surgical aortic valve replacement (AVR).

METHODS

We performed a retrospective, single-center study involving 2628 consecutive patients undergoing elective, primary isolated surgical AVR from 2008 to 2018. A total of 268/2628 patients (10.1%) exhibited AF before surgery. The effect of preoperative AF on mortality was evaluated with univariate and multivariate analyses.

RESULTS

Short-term mortality was 0.8% and was not different between preoperative AF and SR cohorts. Preoperative AF was highly predictive of long-term mortality (median follow-up of 4 years [Q1-Q3 2-7]; hazard ratio [HR]: 2.24, 95% confidence interval [CI]: 1.79-2.79, p < .001), and remained strongly and independently predictive after adjustment for other risk factors (HR: 1.54, 95% CI: 1.21-1.96, p < .001) compared with preoperative SR. In propensity score-matched analysis, the adjusted mortality risk was higher in the AF cohort (OR: 1.47, 95% CI: 1.04-1.99, p = .03) compared with the SR cohort.

CONCLUSIONS

Preoperative AF was independently predictive of long-term mortality in patients undergoing isolated surgical AVR. It remains to be seen whether concomitant surgery or other preoperative measures to correct AF may impact long-term survival.