Identification of coronary artery calcification can optimize risk stratification in patients with acute chest pain

The Prognostic Value of CAC Zero Among Individuals Presenting With Chest Pain: A Meta-Analysis

BACKGROUND

There is little consensus on whether absence of coronary artery calcium (CAC) can identify patients with chest pain (CP) who can safely avoid additional downstream testing.

OBJECTIVES

The purpose of this study was to conduct a systematic review and meta-analysis investigating the utility of CAC assessment for ruling out obstructive coronary artery disease (CAD) among patients with stable and acute CP, at low-to-intermediate risk of obstructive CAD undergoing coronary computed tomography angiography (CTA).

METHODS

The authors searched online databases for studies published between 2005 and 2021 examining the relationship between CAC and obstructive CAD (≥50% coronary luminal narrowing) on coronary CTA among patients with stable and acute CP.

RESULTS

In this review, the authors included 19 papers comprising 79,903 patients with stable CP and 13 papers including 12,376 patients with acute CP undergoing simultaneous CAC and coronary CTA assessment. Overall, 45% (95% CI: 40%-50%) of patients with stable CP and 58% (95% CI: 50%-66%) of patients with acute CP had CAC = 0. The negative predictive values for CAC = 0 ruling out obstructive CAD were 97% (95% CI: 96%-98%) and 98% (95% CI: 96%-99%) among patients with stable and acute CP, respectively. Additionally, the prevalence of nonobstructive CAD among those with CAC = 0 was 13% (95% CI: 10%-16%) among those with stable CP and 9% (95% CI: 5%-13%) among those with acute CP. A CAC score of zero predicted a low incidence of major adverse cardiac events among patients with stable CP (0.5% annual event rate) and acute CP (0.8% overall event rate).

CONCLUSIONS

Among over 92,000 patients with stable or acute CP, the absence of CAC was associated with a very low prevalence of obstructive CAD, a low prevalence of nonobstructive CAD, and a low annualized risk of major adverse cardiac events. These findings support the role of CAC = 0 in a value-based health care delivery model as a "gatekeeper" for more advanced imaging among patients presenting with CP.

Age and the power of zero CAC in cardiac risk assessment: overview of the literature and a cautionary case

The coronary artery calcium (CAC) score is a marker of advanced coronary atherosclerosis. Numerous prospective cohorts have validated CAC as an independent marker that improves prognostication in atherosclerotic cardiovascular disease (ASCVD) beyond traditional risk factors. Accordingly, CAC is now incorporated into international cardiovascular guidelines as a tool to inform medical decision-making. Particular interest concerns the significance of zero CAC score (CAC=0). While many studies report CAC=0 to virtually exclude obstructive coronary artery disease (CAD), non-negligible rates of obstructive CAD despite CAC=0 are reported in certain populations. Overall, the current literature supports the power of zero CAC as a strong downward risk classifier in older patients, whose CAD burden predominantly involves calcified plaque. However, with their higher burden of non-calcified plaque, CAC=0 does not reliably exclude obstructive CAD in patients under 40 years. Illustrating this point, we present a cautionary case of a 31-year-old patient found to have severe two-vessel CAD despite CAC=0. We highlight the value of coronary computed tomography angiography (CCTA) as the gold-standard non-invasive imaging modality when the diagnosis of obstructive CAD is in question.

Coronary Calcium to Rule Out Obstructive Coronary Artery Disease in Patients With Acute Chest Pain

OBJECTIVES

This study aimed to evaluate the ability of coronary artery calcium (CAC) as an initial diagnostic tool to rule out obstructive coronary artery disease (CAD) in a very large registry of patients presenting to the emergency department (ED) with acute chest pain (CP) who were at low to intermediate risk for acute coronary syndrome (ACS).

BACKGROUND

It is not yet well established whether CAC can be used to rule out obstructive CAD in the ED setting.

METHODS

We included patients from the Baptist Health South Florida Chest Pain Registry presenting to the ED with CP at low to intermediate risk for ACS (Thrombolysis In Myocardial Infarction risk score ≤2, normal/nondiagnostic electrocardiography, and troponin levels) who underwent CAC and coronary computed tomography angiography (CCTA) procedures for evaluation of ACS. To assess the diagnostic accuracy of CAC testing to diagnose obstructive CAD and identify the need for coronary revascularization during hospitalization, we estimated sensitivity, specificity, positive predictive values (PPV), and negative predictive values (NPV).

RESULTS

Our study included 5,192 patients (mean age: 53.5 ± 10.8 years; 46% male; 62% Hispanic). Overall, 2,902 patients (56%) had CAC = 0, of which 135 (4.6%) had CAD (114 [3.9%] nonobstructive and 21 [0.7%] obstructive). Among those with CAC >0, 23% had obstructive CAD. Sensitivity, specificity, PPV, and NPV of CAC testing to diagnose obstructive CAD were 96.2%, 62.4%, 22.4%, and 99.3%, respectively. The NPV for identifying those who needed revascularization was 99.6%. Among patients with CAC = 0, 11 patients (0.4%) underwent revascularization, and the number needed to test with CCTA to detect 1 patient who required revascularization was 264.

CONCLUSIONS

In a large population presenting to ED with CP at low to intermediate risk, CAC = 0 was common. CAC = 0 ruled out obstructive CAD and revascularization in more than 99% of the patients, and <5% with CAC = 0 had any CAD. Integrating CAC testing very early in CP evaluation may be effective in appropriate triage of patients by identifying individuals who can safely defer additional testing and more invasive procedures.

The evolving role of coronary CT angiography in Acute Coronary Syndromes

In the United States, non-obstructive coronary disease has been on the rise, and each year, nearly one million adults suffer myocardial infarction, 70% of which are non-ST-segment elevation myocardial infarction (NSTEMI). In addition, approximately 15% of patients suffering NSTEMI will have subsequent readmission for a recurrent acute coronary syndrome (ACS). While invasive angiography remains the standard of care in the diagnostic and therapeutic approach to these patients, these methods have limitations that include procedural complications, uncertain specificity in diagnosis of the culprit lesion in patients with multi-vessel coronary artery disease (CAD), and challenges in following coronary disease over time. The role of coronary computed tomography angiography (CCTA) for evaluating patients with both stable and acute chest pain has seen a paramount upshift in the last decade. This paper reviews the established role of CCTA for the rapid exclusion of obstructive plaque in troponin negative acute chest pain, while exploring opportunities to address challenges in the current approach to evaluating NSTEMI.

Coronary artery calcium testing in low-intermediate risk symptomatic patients with suspected coronary artery disease: An effective gatekeeper to further testing?

Computed tomography for quantification of coronary artery calcium (CAC) is a simple non-invasive tool to assess atherosclerotic plaque burden. CAC is highly correlated with coronary atherosclerosis and is a robust predictor of cardiovascular outcomes. Recently, the 2018 ACC/AHA Cholesterol Guidelines endorsed the use of CAC scores in asymptomatic, intermediate risk individuals where the decision to initiate stain therapy is uncertain. However, whether quantification of CAC may play a role in the assessment of symptomatic individuals remains a matter of debate. In this review, we examine the evidence for the use of CAC in low-intermediate risk patients with chest pain. This appraisal places a particular focus on the growing body of literature supporting the negative predictive value of a CAC score of zero to rule out significant coronary artery disease in those without high-risk features. We also evaluate current guidelines, limitations, and future research directions for CAC scoring in this important subgroup of patients.

Cardiac Computed Tomography

Unstable coronary plaques that are prone to erosion and rupture are the major cause of acute coronary syndromes. Our expanding understanding of the biological mechanisms of coronary atherosclerosis and rapid technological advances in the field of medical imaging has established cardiac computed tomography as a first-line diagnostic test in the assessment of suspected coronary artery disease, and as a powerful method of detecting the vulnerable plaque and patient. Cardiac computed tomography can provide a noninvasive, yet comprehensive, qualitative and quantitative assessment of coronary plaque burden, detect distinct high-risk morphological plaque features, assess the hemodynamic significance of coronary lesions and quantify the coronary inflammatory burden by tracking the effects of arterial inflammation on the composition of the adjacent perivascular fat. Furthermore, advances in machine learning, computational fluid dynamic modeling, and the development of targeted contrast agents continue to expand the capabilities of cardiac computed tomography imaging. In our Review, we discuss the current role of cardiac computed tomography in the assessment of coronary atherosclerosis, highlighting its dual function as a clinical and research tool that provides a wealth of structural and functional information, with far-reaching diagnostic and prognostic implications.

Diagnostic and Prognostic Role of the Modified Diamond-Forrester Model in Combination With Coronary Calcium Score in Acute Chest Pain Patients

BACKGROUND

The aim of this study was to evaluate whether pretest probability (PTP) assessment using the Diamond-Forrester Model (DFM) combined with coronary calcium scoring (CCS) can safely rule out obstructive coronary artery disease (CAD) and 30-day major adverse cardiovascular events (MACE) in acute chest pain patients.

METHODS

We retrospectively evaluated consecutive patients, age ≥18 years, with no known CAD, negative initial electrocardiogram, and troponin level. All patients had coronary computed tomographic angiography (CCTA) with CCS, and our final cohort consisted of 1988 patients. Obstructive CAD was defined as luminal narrowing of ≥50% in 1 or more vessels by CCTA. Patients were classified according to PTP as low (<10%), intermediate (10%-90%), or high (>90%).

RESULTS

The DFM classified 293 (14.7%), 1445 (72.7%), and 250 (12.6%) of patients as low, intermediate, and high risk, respectively, with corresponding 30-day MACE rates of 0.0%, 2.35%, and 14.8%. For patients with intermediate PTP and CCS ≤10, the negative predictive value was 99.2% (95% confidence interval: 98.7-99.8) for 30-day MACE while it was 92.62% (95% confidence interval: 87.9-97.3) for patients with high PTP. Among patients with a high PTP and CCS of zero, the prevalence of 30-day MACE and obstructive CAD remained high (7.07% and 10.1%, respectively).

CONCLUSIONS

In acute chest pain patients without evidence of ischemia on initial electrocardiogram and cardiac troponin, low PTP by DFM or the combination of intermediate PTP and CCS ≤10 had excellent negative predictive values to rule out 30-day MACE. CCS is not sufficient to exclude obstructive CAD and 30-day MACE in patients with high PTP.

A Survey on Coronary Atherosclerotic Plaque Tissue Characterization in Intravascular Optical Coherence Tomography

PURPOSE OF REVIEW

Atherosclerotic plaque deposition within the coronary vessel wall leads to arterial stenosis and severe catastrophic events over time. Identification of these atherosclerotic plaque components is essential to pre-estimate the risk of cardiovascular disease (CVD) and stratify them as a high or low risk. The characterization and quantification of coronary plaque components are not only vital but also a challenging task which can be possible using high-resolution imaging techniques.

RECENT FINDING

Atherosclerotic plaque components such as thin cap fibroatheroma (TCFA), fibrous cap, macrophage infiltration, large necrotic core, and thrombus are the microstructural plaque components that can be detected with only high-resolution imaging modalities such as intravascular ultrasound (IVUS) and optical coherence tomography (OCT). Light-based OCT provides better visualization of plaque tissue layers of coronary vessel walls as compared to IVUS. Three dominant paradigms have been identified to characterize atherosclerotic plaque components based on optical attenuation coefficients, machine learning algorithms, and deep learning techniques. This review (condensation of 126 papers after downloading 150 articles) presents a detailed comparison among various methodologies utilized for plaque tissue characterization, classification, and arterial measurements in OCT. Furthermore, this review presents the different ways to predict and stratify the risk associated with the CVD based on plaque characterization and measurements in OCT. Moreover, this review discovers three different paradigms for plaque characterization and their pros and cons. Among all of the techniques, a combination of machine learning and deep learning techniques is a best possible solution that provides improved OCT-based risk stratification.