Coronary Artery Calcium Scoring: Current Status and Future Directions

Pathophysiology and clinical implications of coronary artery calcifications

PURPOSE OF REVIEW

To provide a summary of current understanding of coronary artery calcifications (CACs), outlining the role of calcium in atherosclerosis to comprehend the clinical implications of CAC.

RECENT FINDINGS

CAC serves as a reliable indicator of coronary artery disease (CAD) and it is associated with cardiovascular events. In recognition of its significance, recent global guidelines have integrated CAC assessment into risk evaluation protocols, highlighting its role as a noninvasive tool for evaluating and stratifying patients' risk for cardiovascular events. Beyond the amount of CAC values, also, calcium morphology had been linked to cardiovascular events.By leveraging CAC assessment, healthcare providers can effectively up or down reclassify patients' risk and tailor preventive strategies accordingly. This comprehensive approach may involve lifestyle modifications, meticulous management of risk factors, and judicious use of preventive medications to mitigate the likelihood of future cardiovascular events, or withhold treatments in those without signs of CAC, to optimize resource use.

SUMMARY

The identification of CAC burden and morphology through noninvasive imaging modalities can reclassify the prediction of future cardiovascular risk and serve as a risk modifier for atherosclerosis. These data underscore the utility of selectively using CAC assessment in both primary and secondary prevention strategies for atherosclerotic cardiovascular disease.

Discrepancies between Coronary Artery Calcium Score and Coronary Artery Disease Severity in Computed Tomography Angiography Studies

The aim of this paper is to demonstrate the difference in usefulness of the coronary artery calcium score (CACS) and the full assessment of the severity of coronary artery disease in coronary computed tomography angiography (CCTA) studies. The difference between the population risk of coronary artery disease (CAD) assessed by the CACS and the severity of CAD was demonstrated in images from two CCTA studies. The first image is from a patient with a CACS of 0 and significant coronary artery stenosis. In the native phase of CCTA examination, no calcified changes were detected in the topography of the coronary arteries. In the middle section of the left descending artery (LAD), at the level of the second diagonal branch (Dg2), a large non-calcified atherosclerotic plaque was visible. Mid-LAD stenosis was estimated to be approximately 70%. The second image features a patient with a high CACS but no significant coronary artery stenosis. The calcium score of individual coronary arteries calculated using the Agatston method was as follows: left main (LM) 0, LAD 403, left circumflex (LCx) 207.7, right coronary artery (RCA) 12. CACS was 622.7, representing a significant population risk of significant CAD. In the proximal and middle sections of the LAD, numerous calcified and mixed atherosclerotic plaques with positive remodeling were visible, causing stenosis of 25-50%. Similarly, in the proximal and middle sections of the LCx, numerous calcified and mixed atherosclerotic plaques with positive remodeling were visualized, causing stenoses of 25-50%. Calcified atherosclerotic plaques were found in the RCA, causing stenosis <25%. The entire CCTA image met CAD-RADS 2 (coronary artery disease reporting and data system) criteria. In summary, CACS may be applicable in population-based studies to assess the risk of significant CAD. In the evaluation of individual patients, a comprehensive assessment of CAD severity based on the angiographic phase of the CCTA examination should be used.

Progression of Coronary Artery Calcification According to Changes in Risk Factors in Asymptomatic Individuals

This retrospective study aimed to assess coronary artery calcium (CAC) progression in serial computed tomography measurements according to risk factor changes. In 448 asymptomatic adults who underwent CAC measurements with more than one-year intervals, CAC progression was assessed according to age, sex, variable traditional risk factors (diabetes mellitus, hypertension, hyperlipidemia, and smoking), and initial CAC score (0, 0.1-100, and >100). Univariate and multivariate logistic regression analyses were assessed for independent predictors of rapid CAC progression (ΔCAC/year > 20). During the 3.5-year follow-up, coronary artery calcifications occurred in 43 (12.8%) of 336 individuals with an initial CAC score of zero. Of 112 individuals with initial CAC presence, 60 (53.6%) had ΔCAC/year > 20. Age, male sex, body mass index, and all risk factors were significantly associated with ΔCAC/year > 20, but recently diagnosed hypertension (odds ratio [OR], 11.3) and initial CAC score (OR, 1.05) were significant independent predictors in multivariate regression analyses. CAC progression was affected by demographic and traditional risk factors; but, adjusting for these factors, recently diagnosed hypertension and initial CAC score were the most influential factors for rapid CAC progression. These findings suggest that individuals with higher initial CAC scores may benefit from more frequent follow-up scans and checks regarding risk factor changes.

Coronary artery calcium quantification technique using dual energy material decomposition: a simulation study

Coronary artery calcification is a significant predictor of cardiovascular disease, with current detection methods like Agatston scoring having limitations in sensitivity. This study aimed to evaluate the effectiveness of a novel CAC quantification method using dual-energy material decomposition, particularly its ability to detect low-density calcium and microcalcifications. A simulation study was conducted comparing the dual-energy material decomposition technique against the established Agatston scoring method and the newer volume fraction calcium mass technique. Detection accuracy and calcium mass measurement were the primary evaluation metrics. The dual-energy material decomposition technique demonstrated fewer false negatives than both Agatston scoring and volume fraction calcium mass, indicating higher sensitivity. In low-density phantom measurements, material decomposition resulted in only 7.41% false-negative (CAC = 0) measurements compared to 83.95% for Agatston scoring. For high-density phantoms, false negatives were removed (0.0%) compared to 20.99% in Agatston scoring. The dual-energy material decomposition technique presents a more sensitive and reliable method for CAC quantification.

Calcified coronary lesions: Imaging, prognosis, preparation and treatment state of the art review

Calcific coronary artery stenosis is a complex disease associated with adverse outcomes and suboptimal percutaneous treatment. Calcium plaque modification has emerged as a key strategy to tackle the issues that accompany calcific stenosis - namely reduced device deliverability, unpredictable lesion characteristics, and difficult dilatation. Atherectomy has traditionally been the treatment modality of choice for heavily calcified coronary stenoses. Contemporary technologies have emerged to aid with planning, preparation, and treatment of calcified coronary stenosis in an attempt to improve procedural success and long-term outcomes. In this State Of The Art Review, we synthesize the body of data surrounding the diagnosis, imaging, and treatment of calcific coronary disease, with a focus on i) intravascular imaging, ii) calcific lesion preparation, iii) treatment modalities including atherectomy, and iv) updated treatment algorithms for the management of calcified coronary stenosis.

Influence of Deep Learning Based Image Reconstruction on Quantitative Results of Coronary Artery Calcium Scoring

RATIONALE AND OBJECTIVES

To assess the impact of deep learning-based imaging reconstruction (DLIR) on quantitative results of coronary artery calcium scoring (CACS) and to evaluate the potential of DLIR for radiation dose reduction in CACS.

METHODS

For a retrospective cohort of 100 consecutive patients (mean age 62 ±10 years, 40% female), CACS scans were reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction (ASiR-V in 30%, 60% and 90% strength) and DLIR in low, medium and high strength. CACS was quantified semi-automatically and compared between image reconstructions. In a phantom study, a cardiac calcification insert was scanned inside an anthropomorphic thorax phantom at standard dose, 50% dose and 25% dose. FBP reconstructions at standard dose served as the reference standard.

RESULTS

In the patient study, DLIR led to a mean underestimation of Agatston score by 3.5, 6.4 and 11.6 points at low, medium and high strength, respectively. This underestimation of Agatston score was less pronounced for DLIR than for ASiR-V. In the phantom study, quantitative CACS results increased with reduced radiation dose and decreased with increasing strength of DLIR. Medium strength DLIR reconstruction at 50% dose reduction and high strength DLIR reconstruction at 75% dose reduction resulted in quantitative CACS results that were comparable to FBP reconstructions at standard dose.

CONCLUSION

Compared to FBP as the historical reference standard, DLIR leads to an underestimation of CACS but this underestimation is more moderate than with ASiR-V. DLIR can offset the increase in image noise and calcium score at reduced dose and may thus allow for substantial radiation dose reductions in CACS studies.

Trends in Coronary Artery Anomalies Detection by Coronary Computed Tomography Angiography (CCTA): A Real-Life Comparative Study before and during the COVID-19 Pandemic

BACKGROUND

In the wake of the coronavirus disease 19 (COVID-19) pandemic, affecting healthcare systems globally, urgent research is needed to understand its potential repercussions on the diagnosis and management of cardiovascular disorders. This emphasises the importance of detecting coronary artery anomalies (CAAs), rare conditions that can range from benign to potentially life-threatening manifestations. We aimed to retrospectively assess the impact of the COVID-19 pandemic on the detection of various coronary anomalies using Coronary Computed Tomography Angiography (CCTA) within a regional tertiary cardiology unit in north-eastern Romania, focusing on perceived occurrence in the population under study, types, and related demographic and clinical factors.

METHODS

We analysed CCTA scans and investigated the trends in CAA detection among cardiology patients over a decade. We compared pre-COVID-19 and pandemic-era data to assess the impact of healthcare utilisation, patient behaviour, and diagnostic approaches on anomaly detection.

RESULTS

Our analysis revealed a higher detection rate of CAAs during the pandemic (3.9% versus 2.2%), possibly highlighting differences in patient clinical profile and addressability changes presentation compared to the previous period. Origination and course anomalies, often linked to severe symptoms, were significantly higher pre-COVID-19 (64.1% versus 51.3%). Conversely, intrinsic CAAs, typically asymptomatic or manifesting later in life, notably increased during the pandemic (49.0% versus 61.4%; p = 0.020).

CONCLUSIONS

Our study underscores a significant rise in CAA detection during the COVID-19 era, potentially linked to changes in cardiovascular and respiratory clinical patterns, with advanced imaging modalities like CCTA offering accuracy in identification.

Artificial intelligence in coronary artery calcium score: rationale, different approaches, and outcomes

Almost 35 years after its introduction, coronary artery calcium score (CACS) not only survived technological advances but became one of the cornerstones of contemporary cardiovascular imaging. Its simplicity and quantitative nature established it as one of the most robust approaches for atherosclerotic cardiovascular disease risk stratification in primary prevention and a powerful tool to guide therapeutic choices. Groundbreaking advances in computational models and computer power translated into a surge of artificial intelligence (AI)-based approaches directly or indirectly linked to CACS analysis. This review aims to provide essential knowledge on the AI-based techniques currently applied to CACS, setting the stage for a holistic analysis of the use of these techniques in coronary artery calcium imaging. While the focus of the review will be detailing the evidence, strengths, and limitations of end-to-end CACS algorithms in electrocardiography-gated and non-gated scans, the current role of deep-learning image reconstructions, segmentation techniques, and combined applications such as simultaneous coronary artery calcium and pulmonary nodule segmentation, will also be discussed.

Diagnostic Ability of Manual Calcification Length Assessment on Non-Electrocardiographically Gated Computed Tomography for Estimating the Presence of Coronary Artery Disease

Background: Coronary artery calcification score (CACS) on electrocardiography (ECG)-gated computed tomography (CT) is used for risk stratification of atherosclerotic cardiovascular disease, which requires dedicated analytic software. In this study, we evaluated the diagnostic ability of manual calcification length assessment on non-ECG-gated CT for epicardial coronary artery disease (CAD). Methods: A total of 100 patients undergoing both non-ECG-gated plain CT scans with a slice interval of 1.25 mm and invasive coronary angiography were retrospectively included. We manually measured the length of the longest calcified lesions of coronary arteries on each branch. The relationship between the number of coronary arteries with the length of coronary calcium > 5, 10, or 15 mm and the presence of epicardial CAD on invasive angiography was evaluated. Standard CACS was also evaluated using established software. Results: Of 100 patients, 49 (49.0%) had significant epicardial CAD on angiography. The median standard CACS was 346 [7, 1965]. In both manual calcium assessment and standard CACS, the increase in calcium burden was progressively associated with the presence of epicardial CAD on angiography. The receiver operating characteristic curve analysis showed similar diagnostic abilities of the two diagnostic methods. The best cut-off values for CAD were 2, 1, and 1 for the number of vessels with calcium > 5, 10, and 15 mm, respectively. Overall, the diagnostic ability of manual calcium assessment was similar to that of standard CACS > 400. Conclusions: Manual assessment of coronary calcium length on non-ECG-gated plain CT provided similar diagnostic ability for the presence of significant epicardial CAD on invasive angiography, as compared to standard CACS.

Immune checkpoint inhibitors in cancer: the increased risk of atherosclerotic cardiovascular disease events and progression of coronary artery calcium

BACKGROUND

Immune checkpoint inhibitors (ICIs) have contributed to a significant advancement in the treatment of cancer, leading to improved clinical outcomes in many individuals with advanced disease. Both preclinical and clinical investigations have shown that ICIs are associated with atherosclerosis and other cardiovascular events; however, the exact mechanism underlying this relationship has not been clarified.

METHODS

Patients diagnosed with stages III or IV non-small cell lung cancer (NSCLC) at the Wuhan Union Hospital from March 1, 2020, to April 30, 2022, were included in this retrospective study. Coronary artery calcium (CAC) volume and score were assessed in a subset of patients during non-ECG-gated chest CT scans at baseline and 3, 6, and 12 months after treatment. Propensity score matching (PSM) was performed in a 1:1 ratio to balance the baseline characteristics between the two groups.

RESULTS

Overall, 1458 patients (487 with ICI therapy and 971 without ICI therapy) were enrolled in this cardiovascular cohort study. After PSM, 446 patients were included in each group. During the entire period of follow-up (median follow-up 23.1 months), 24 atherosclerotic cardiovascular disease (ASCVD) events (4.9%) occurred in the ICI group, and 14 ASCVD events (1.4%) in the non-ICI group, before PSM; 24 ASCVD events (5.4%) occurred in the ICI group and 5 ASCVD events (1.1%) in the non-ICI group after PSM. The CAC imaging study group comprised 113 patients with ICI therapy and 133 patients without ICI therapy. After PSM, each group consisted of 75 patients. In the ICI group, the CAC volume/score increased from 93.4 mm3/96.9 (baseline) to 125.1 mm3/132.8 (at 12 months). In the non-ICI group, the CAC volume/score was increased from 70.1 mm3/68.8 (baseline) to 84.4 mm3/87.9 (at 12 months). After PSM, the CAC volume/score was increased from 85.1 mm3/76.4 (baseline) to 111.8 mm3/121.1 (12 months) in the ICI group and was increased from 74.9 mm3/76.8 (baseline) to 109.3 mm3/98.7 (12 months) in the non-ICI group. Both cardiovascular events and CAC progression were increased after the initiation of ICIs.

CONCLUSIONS

Treatment with ICIs was associated with a higher rate of ASCVD events and a noticeable increase in CAC progression.

Association between the homeostasis model assessment of insulin resistance and coronary artery calcification: a meta-analysis of observational studies

Background

Insulin resistance (IR), a risk factor for cardiovascular diseases, has garnered significant attention in scientific research. Several studies have investigated the correlation between IR and coronary artery calcification (CAC), yielding varying results. In light of this, we conducted a systematic review to investigate the association between IR as evaluated by the homeostasis model assessment (HOMA-IR) and CAC.

Methods

A comprehensive search was conducted to identify relevant studies in PubMed, Embase, Scopus, and Web of Science databases. In addition, preprint servers such as Research Square, BioRxiv, and MedRxiv were manually searched. The collected data were analyzed using either fixed or random effects models, depending on the heterogeneity observed among the studies. The assessment of the body of evidence was performed using the GRADE approach to determine its quality.

Results

The current research incorporated 15 studies with 60,649 subjects. The analysis revealed that a higher category of HOMA-IR was associated with a greater prevalence of CAC in comparison to the lowest HOMA-IR category, with an OR of 1.13 (95% CI: 1.06-1.20, I2 = 29%, P < 0.001). A similar result was reached when HOMA-IR was analyzed as a continuous variable (OR: 1.27, 95% CI: 1.14-1.41, I2 = 54%, P < 0.001). In terms of CAC progression, a pooled analysis of two cohort studies disclosed a significant association between increased HOMA-IR levels and CAC progression, with an OR of 1.44 (95% CI: 1.04-2.01, I2 = 21%, P < 0.05). It is important to note that the strength of the evidence was rated as low for the prevalence of CAC and very low for the progression of CAC.

Conclusion

There is evidence to suggest that a relatively high HOMA-IR may be linked with an increased prevalence and progression of CAC.

Computed Tomography (CT) Calcium Scoring in Primary Prevention of Acute Coronary Syndrome and Future Cardiac Events in Patients With Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a complex and chronic autoimmune disease that impacts multiple organ systems and presents with varying symptomatology that makes targeting treatment extremely difficult. The cardiovascular system and more specifically the coronary arteries are heavily affected by SLE causing increased atherosclerosis and subsequently increased acute coronary syndrome (ACS) and increased future cardiac events. ACS is a common occurrence in patients with SLE due to the premature development of atherosclerosis due to the dysregulation of pro-inflammatory cytokines. Calcium scoring has been effectively utilized to identify plaque burden in patients with coronary artery calcification (CAC). Calcium scoring is a score obtained from a computed tomography (CT) image using non-contrast imaging, which provides quantitative information regarding CAC and aids in assessing cardiovascular risk. A calcium score of zero Hounsfeild units can be obtained using CT calcium scoring which indicates no calcium is identified in the coronary arteries and is a strong negative risk predictor for coronary artery disease. Early screening of SLE patients with CT calcium scoring could aid in early detection and treatment subsequently leading to delay of premature coronary atherosclerosis and future cardiac events in this patient population. Multiple studies have used calcium scoring as a method to measure arterial calcification in SLE patients. The Society of Cardiovascular Imaging has now endorsed the idea of obtaining a baseline calcium artery score with a repeat progression scan in 3-5 years. Calcium scoring has also been identified as an effective initial tool for stratification and identification of possible ACS. The various advantages of early calcium scoring signify the further research needed to fully understand and implement the advantages calcium scoring has to offer patients with SLE.

Reporting and Outcomes of Coronary Calcification on Lung Cancer Screening CT

RATIONALE AND OBJECTIVES

To evaluate the accuracy and downstream testing and statin prescribing of real-world reporting of coronary calcification on lung cancer screening (LCS) CT.

MATERIALS AND METHODS

We retrospectively reviewed LCS CTs from January 2015 to November 2021 for reporting of coronary calcification; reports that denoted coronary calcification as a significant incidental finding ("S" modifier) were also noted. We evaluated calcium scoring accuracy in patients in whom a cardiac or calcium scoring CT was performed within 1 year of the LCS CT. For the first LCS CT in all patients, we evaluated whether a stress test was performed within 6 months and whether a new statin prescription was written within 90 days of the LCS CT. Patients were stratified by atherosclerotic cardiovascular disease (ASCVD) risk group, used in a multivariable regression analysis for new statin prescriptions.

RESULTS

Eight thousand nine hundred eighty-seven patients underwent screening. In 117 patients who had a paired cardiac CT, scores were concordant in 65 (56%), and LCS CTs did not mention or underestimated calcifications in 40 (34%). Reporting of coronary artery calcifications led to new statin prescriptions, with OR of 1.8 for calcifications without S modifier and 4.4 for calcifications with S modifier. Reporting of coronary artery calcification with S modifier led to subsequent stress testing in 141/1582 (9%) of patients.

CONCLUSION

Coronary calcifications are frequently not mentioned or underestimated at LCS CT. Reporting of coronary calcifications leads to new statin prescriptions, and radiologists should consider reporting these to allow for a risk-benefit discussion with the patient's physician.

Imaging Early Life Cardiovascular Phenotype

The growing epidemics of obesity, hypertension, and diabetes, in addition to worsening environmental factors such as air pollution, water scarcity, and climate change, have fueled the continuously increasing prevalence of cardiovascular diseases (CVDs). This has caused a markedly increasing burden of CVDs that includes mortality and morbidity worldwide. Identification of subclinical CVD before overt symptoms can lead to earlier deployment of preventative pharmacological and nonpharmacologic strategies. In this regard, noninvasive imaging techniques play a significant role in identifying early CVD phenotypes. An armamentarium of imaging techniques including vascular ultrasound, echocardiography, magnetic resonance imaging, computed tomography, noninvasive computed tomography angiography, positron emission tomography, and nuclear imaging, with intrinsic strengths and limitations can be utilized to delineate incipient CVD for both clinical and research purposes. In this article, we review the various imaging modalities used for the evaluation, characterization, and quantification of early subclinical cardiovascular diseases.