Evaluation of Atherosclerotic Plaque in Non-invasive Coronary Imaging

Coronary Physiology-Based Approaches for Plaque Vulnerability: Implications for Risk Prediction and Treatment Strategies

In the catheterization laboratory, the measurement of physiological indexes can help identify functionally significant lesions and has become one of the standard methods to guide treatment decision-making. Plaque vulnerability refers to a coronary plaque susceptible to rupture, enabling risk prediction before coronary events, and it can be detected by defining a certain type of plaque morphology on coronary imaging modalities. Although coronary physiology and plaque vulnerability have been considered different attributes of coronary artery disease, the underlying pathophysiological basis and clinical data indicate a strong correlation between coronary hemodynamic properties and vulnerable plaque. In prediction of coronary events, emerging data have suggested independent and additional implications of a physiology-based approach to a plaque-based approach. This review covers the fundamental interplay between coronary physiology and plaque morphology during disease progression with clinical data supporting this relationship and examines the clinical relevance of physiological indexes in prediction of clinical outcomes and therapeutic decision-making along with plaque vulnerability.

Relationship of cardiovascular risk factors, pericardial fat, and carotid thickness with coronary plaque type in patients with diabetes mellitus

Background

There is paucity of data on the potential predictors of coronary plaque types among patients with diabetes mellitus(DM).

Aims

To assess the association of cardiovascular risk factors, pericardial fat volume (PFV) assessed by multi-detector CT(MDCT)angiography, and internal carotid intima media thickness with coronary atherosclerotic plaque types in patients with type 2 DM.

Patients and methods

Patients with suspected coronary artery disease who underwent 64-slice MDCT angiography were enrolled in this retrospective study.

Results

A total of 784 patients were enrolled in this study, 198 of whom had DM and 586 of whom did not. The prevalence of calcified and mixed plaques was significantly higher in the DM group than without DM group, while no significant difference was found in the distribution of non-calcified plaque between groups. There was significant association between smoking [OR(CI) = 4(2-10),P = 0.001] and increased age[OR(CI) = 1.1(1-1.3),P = 0.023] and calcified plaque presence. Regarding mixed and non-calcified plaque, increased PFV[OR(CI) = 1.1(1-1.3),P = 0.001] and positive family history[OR(CI) = 4(2-12),P = 0.049] showed a significant association with coronary mixed plaque presence while no significant association was observed between cardiovascular risk factors, PFV, and internal carotid intima media thickness and non-calcified plaque presence in patients with DM.

Conclusion

Increased PFV showed significant and independent association with mixed coronary plaques development, which suggests that PFV may be used as an imaging marker for early detection of increased risk for future coronary events in patients with DM.

Periodontal Disease Is Associated with Increased Vulnerability of Coronary Atheromatous Plaques in Patients Undergoing Coronary Computed Tomography Angiography-Results from the Atherodent Study

The present study aimed to investigate the link between the severity of periodontal disease (PD), coronary calcifications and unstable plaque features in patients who underwent coronary computed tomography for unstable angina (UA). Fifty-two patients with UA, included in the ATHERODENT trial (NCT03395041), underwent computed tomographic coronary angiography (CCTA) and dental examination. Based on the median value of the periodontal index (PI), patients were assigned to the low periodontal index (LPI) group (PI < 22) and a high periodontal index (HPI) group (PI > 22). Patients with HPI had higher plaque volume (p = 0.013) and noncalcified plaque volume (p = 0.0003) at CCTA. In addition, the presence of vulnerability features in the atheromatous plaques was significantly correlated with PI (p = 0.001). Among periodontal indices, loss of gingival attachment (p = 0.009) and papillary bleeding index (p = 0.002) were strongly associated with high-risk plaques. PI significantly correlated with coronary calcium score (r = 0.45, p = 0.0008), but not with traditional markers of subclinical atherosclerosis. Overall, this subgroup analysis of the ATHERODENT study indicates that patients with advanced PD and UA present a higher amount of calcium in the coronary tree and have a more vulnerable phenotype of their culprit plaques.

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.

Combined non-invasive scan and biomarkers to identify independent risk factors in patients with mild coronary stenosis

Background

Independent risk factors for major adverse cardiovascular events (MACEs) in patients with mild coronary stenosis are uncertain. This study aims to investigate predictive biomarkers for MACEs in patients with mild coronary stenosis.

Methods

Totally 381 patients with mild coronary stenosis were included and MACE incidences were recorded through a 24-month follow-up and 91 patients with unfavorable plaques characteristic are detected by CCTA. One unfavorable characteristic was recorded for 1 point and they were divided into three groups: high-risk group (HR, score =0), intermediate-risk group (IR, score =1) and low-risk group (LR, score/2). Specific blood biomarker measurements of high-sensitivity C-reactive protein (hs-CRP), matrix metallopeptidase 9 (MMP-9), and myeloperoxidase (MPO) were taken simultaneously.

Results

The mean age, hs-CRP and MPO levels in the HR and IR group were significantly higher than that in the LR group. A considerably higher level of MMP-9 showed in the HR group compared to the LR group. The incidence rates of MACE were remarkably higher in HR group than LR group and IR group. Kaplan-Meier survival analysis demonstrated that the cumulative event—free survival rate of HR was significantly higher than that in LR and IR group and there was no significant difference between LR and IR group. The univariate COX regression analysis indicated that the age, hs-CRP, MPO, and unfavorable plaque scores ≥2 were independent risk factors for MACEs.

Conclusions

High MPO levels were strongly correlated with MACEs in patients with mild coronary stenosis. Although confirmation is needed from larger trials, MPO could be a promising clinical tool to improve the risk stratification in patients with mild coronary stenosis and suggest strategies for the individualized prevention programs.

Feasibility and Applicability of Wireless Handheld Ultrasound Measurement of Carotid Intima-Media Thickness in Patients with Cardiac Symptoms

PURPOSE

Routine screening for carotid intima-media thickness (CIMT) and cardiovascular (CV) disease in asymptomatic patients has been criticized for the high costs and large number of patients required for detecting one patient with coronary artery disease (CAD). In order to overcome the low cost-effectiveness thereof, we investigated the feasibility of an economic wireless handheld ultrasound (WHUS) device for CIMT measurement in symptomatic patients.

MATERIALS AND METHODS

A total of 100 consecutive patients with cardiac symptoms were enrolled. CIMT was measured in all patients. Coronary angiography was performed in 75 patients indicated for the exam.

RESULTS

The mean of maximal CIMT measured from left/right common carotid artery and bulb (max-CIMT) by the WHUS device showed excellent agreement [intraclass correlation coefficient (ICC)=0.960] with a standard ultrasound device and great interobserver repeatability (ICC>0.9 between all observers). Receiver operating characteristic curve analysis showed that the predictive power for CAD was improved when max-CIMT and plaque information (plaque≥2) was added [area under the curve (AUC): 0.838] to the traditional clinical CV risk factors (AUC: 0.769). The cutoff values for CAD prediction with the standard device and the WHUS device were 1.05 mm (AUC: 0.807, sensitivity: 0.78, specificity: 0.53) and 1.10 mm (AUC: 0.725, sensitivity: 0.98, specificity: 0.27), respectively.

CONCLUSION

max-CIMT measured by a WHUS device showed excellent agreement and repeatability, compared with standard ultrasound. Combined max-CIMT and plaque information added predictive power to the traditional clinical CV risk factors in detecting high-risk CAD patients.

Coronary Computed Tomography Angiography for the Diagnosis of Vasospastic Angina: Comparison with Invasive Coronary Angiography and Ergonovine Provocation Test

OBJECTIVE

To investigate the diagnostic validity of coronary computed tomography angiography (cCTA) in vasospastic angina (VA) and factors associated with discrepant results between invasive coronary angiography with the ergonovine provocation test (iCAG-EPT) and cCTA.

MATERIALS AND METHODS

Of the 1397 patients diagnosed with VA from 2006 to 2016, 33 patients (75 lesions) with available cCTA data from within 6 months before iCAG-EPT were included. The severity of spasm (% diameter stenosis [%DS]) on iCAG-EPT and cCTA was assessed, and the difference in %DS (Δ%DS) was calculated. Δ%DS was compared after classifying the lesions according to pre-cCTA-administered sublingual nitroglycerin (SL-NG) or beta-blockers. The lesions were further categorized with %DS ≥ 50% on iCAG-EPT or cCTA defined as a significant spasm, and the diagnostic performance of cCTA on identifying significant spasm relative to iCAG-EPT was assessed.

RESULTS

Compared to lesions without SL-NG treatment, those with SL-NG treatment showed a higher Δ%DS (39.2% vs. 22.1%, p = 0.002). However, there was no difference in Δ%DS with or without beta-blocker treatment (35.1% vs. 32.6%, p = 0.643). The significant difference in Δ%DS associated with SL-NG was more prominent in patients who were aged < 60 years, were male, had body mass index < 25 kg/m², and had no history of hypertension, diabetes, or dyslipidemia. Based on iCAG-EPT as the reference, the per-lesion-based sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of cCTA for VA diagnosis were 7.5%, 94.0%, 60.0%, 47.1%, and 48.0%, respectively.

CONCLUSION

For patients with clinically suspected VA, confirmation with iCAG-EPT needs to be considered without completely excluding the diagnosis of VA simply based on cCTA results, although further prospective studies are required for confirmation.

Evaluation of Coronary Artery Calcium Progression in Asymptomatic Individuals with an Initial Score of Zero

Background and Objectives

Coronary artery calcium (CAC) scoring in the asymptomatic population can improve cardiovascular risk prediction. We aimed to assess CAC progression and the impact of coronary risk factors on the CAC progression rate in asymptomatic Korean individuals with a baseline CAC score of zero.

Methods

The study population was derived from the Korea Initiatives on Coronary Artery Calcification (KOICA) registry: a retrospective, single ethnicity, multicenter registry of asymptomatic individuals who underwent CAC scoring as a part of a health checkup. Individuals with at least two CAC scores and an initial score of zero were included. CAC progression was defined as [√CAC score (follow-up) − √CAC score (baseline)] ≥2.5. The 10-year atherosclerotic cardiovascular disease (ASCVD) risk was calculated.

Results

Among 6,268 participants (mean age, 48.0±7.1 years; male, 80.5%), 719 (11.5%) experienced CAC progression during follow-up (median, 109 months; interquartile range, 78–208 months). The CAC progression rate was 0.3%, 1.9%, 4.3%, 8.6%, and 16.7% in years 1–5, respectively. The chance of CAC progression at 5 years was 13.1%, 22.0%, and 27.9% for individuals with a 10-year ASCVD risk of <5%, ≥5% but <7.5%, and ≥7.5%, respectively. A multivariable analysis revealed age, male sex, waist circumference, diabetes, and low-density lipoprotein cholesterol level as independently associated with annualized CAC progression (p<0.001, p=0.017, p=0.025, p=0.032, and p=0.003, respectively).

Conclusions

The probability of CAC progression is very low in Korean individuals with a CAC score of zero. However, the risk of CAC progression increases nonlinearly over time, and increases as the 10-year ASCVD risk increases.