Coronary Artery Calcium Testing in Symptomatic Patients: An Issue of Diagnostic Efficiency

Beyond symptoms: Unlocking the potential of coronary calcium scoring in the prevention and treatment of coronary artery disease

Coronary Artery Disease (CAD) represents a persistent global health menace, particularly prevalent in Eastern European nations. Often asymptomatic until its advanced stages, CAD can precipitate life-threatening events like myocardial infarction or stroke. While conventional risk factors provide some insight into CAD risk, their predictive accuracy is suboptimal. Amidst this, Coronary Calcium Scoring (CCS), facilitated by non-invasive computed tomography (CT), emerges as a superior diagnostic modality. By quantifying calcium deposits in coronary arteries, CCS serves as a robust indicator of atherosclerotic burden, thus refining risk stratification and guiding therapeutic interventions. Despite certain limitations, CCS stands as an instrumental tool in CAD management and in thwarting adverse cardiovascular incidents. This review delves into the pivotal role of CCS in CAD diagnosis and treatment, elucidates the involvement of calcium in atherosclerotic plaque formation, and outlines the principles and indications of utilizing CCS for predicting major cardiovascular events.

Coronary Calcium Risk Score and Cardiovascular Risk

The association between the presence of coronary artery calcium (CAC) and the risk of coronary artery disease (CAD) has been appreciated for decades. In this review, we critically appraise the role of CAC based on computerized tomography in contemporary risk stratification. Available evidence suggests that the measurement of CAC is a useful modality in many patients for more precise risk stratification and prognostic determination. Whether newer CAC score incorporating extra coronary calcification will add incremental value, especially for stroke and other non-coronary vascular outcomes, needs a prospective study.

Coronary artery calcium scoring: an evidence-based guide for primary care physicians

Primary care physicians often must decide whether statin therapy would be appropriate (in addition to lifestyle modification) for managing asymptomatic individuals with borderline or intermediate risk for developing atherosclerotic cardiovascular disease (ASCVD), as assessed on the basis of traditional risk factors. In appropriate subjects, a simple, noninvasive measurement of coronary artery calcium can help clarify risk. Coronary atherosclerosis is a chronic inflammatory disease, with atherosclerotic plaque formation involving intimal inflammation and repeated cycles of erosion and fibrosis, healing and calcification. Atherosclerotic plaque formation represents the prognostic link between risk factors and future clinical events. The presence of coronary artery calcification is almost exclusively an indication of coronary artery disease, except in certain metabolic conditions. Coronary artery calcification can be detected and quantified in a matter of seconds by noncontrast electrocardiogram-gated low-dose X-ray computed tomography (coronary artery calcium scoring [CACS]). Since the publication of the seminal work by Dr. Arthur Agatston in 1990, a wealth of CACS-based prognostic data has been reported. In addition, recent guidelines from various professional societies conclude that CACS may be considered as a tool for reclassifying risk for atherosclerotic cardiovascular disease in patients otherwise assessed to have intermediate risk, so as to more accurately inform decisions about possible statin therapy in addition to lifestyle modification as primary preventive therapy. In this review, we provide an overview of CACS, from acquisition to interpretation, and summarize the scientific evidence for and the appropriate use of CACS as put forth in current clinical guidelines.

The Prognostic Value of a Validated and Automated Intravascular Ultrasound-Derived Calcium Score

Background

Coronary calcification has been linked to cardiovascular events. We developed and validated an algorithm to automatically quantify coronary calcifications on intravascular ultrasound (IVUS). We aimed to assess the prognostic value of an IVUS-calcium score (ICS) on patient-oriented composite endpoint (POCE).

Methods

We included patients that underwent coronary angiography plus pre-procedural IVUS imaging. The ICS was calculated per patient. The primary endpoint was a composite of all-cause mortality, stroke, myocardial infarction, and revascularization (POCE).

Results

In a cohort of 408 patients, median ICS was 85. Both an ICS ≥ 85 and a 100 unit increase in ICS increased the risk of POCE at 6-year follow-up (adjusted hazard ratio (aHR) 1.51, 95%CI 1.05–2.17, p value = 0.026, and aHR 1.21, 95%CI 1.04–1.41, p value = 0.014, respectively).

Conclusions

The ICS, calculated by a validated automated algorithm derived from routine IVUS pullbacks, was strongly associated with the long-term risk of POCE.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s12265-021-10103-1.

Sex differences in impact of coronary artery calcification to predict coronary artery disease

Objective

To assess sex-specific differences regarding use of conventional risks and coronary artery calcification (CAC) to detect coronary artery disease (CAD) using coronary CT angiography (CCTA).

Methods

The Nationwide Gender-specific Atherosclerosis Determinants Estimation and Ischemic Cardiovascular Disease Prospective Cohort study is a prospective, multicentre, nationwide cohort study. Candidates with suspected CAD aged 50–74 years enrolled from 2008 to 2012. The outcome was obstructive CAD defined as any stenosis ≥50% by CCTA. We constructed logistic regression models for obstructive CAD adjusted for conventional risks (clinical model) and CAC score. Improvement in discrimination beyond risks was assessed by C-statistic; net reclassification index (NRI) for CAD probability of low (<30%), intermediate (30%–60%) and high (≥60%); and risk stratification capacity.

Results

Among 991 patients (456 women, 535 men; 65.2 vs 64.4 years old), women had lower CAC scores (median, 4 vs 60) and lower CAD prevalence (21.7% vs 37.0%) than men. CAC significantly improved model discrimination compared with clinical model in both sexes (0.66–0.79 in women vs 0.61–0.83 in men). The NRI for women was 0.33, which was much lower than that for men (0.71). Adding CAC to clinical model had a larger benefit in terms of moving an additional 43.3% of men to the most determinant categories (high or low risk) compared with −1.4% of women.

Conclusions

The addition of CAC to a prediction model based on conventional variables significantly improved the classification of risk in suspected patients with CAD, with sex differences influencing the predictive ability.

Trial registration number

UMIN-CTR Clinical Trial: UMIN000001577.

The prognostic value of CT coronary angiography in patients attending hospital with troponin-negative acute chest pain and inconclusive exercise treadmill tests

AIMS

Once acute coronary syndrome (ACS) is excluded in patients presenting to hospital with acute chest pain, usual practice is to stratify future risk of adverse cardiovascular events. Commonly this is performed by pre-discharge exercise treadmill testing (ETT). Often however, patients are unable to perform the test for various reasons, or the final result is inconclusive. This potentially could lead to uncertainty and to unnecessary invasive coronary angiography. We wished to evaluate the potential prognostic significance of CT coronary angiography (CTCA) in patients with prior inconclusive ETTs.

METHODS AND RESULTS

Two hundred and thirty-two consecutive patients underwent CTCA and calcium scoring following hospital attendance with acute chest pain and following exclusion of ACS. All patients were followed up for a combined primary outcome of death, non-fatal myocardial infarction, and late revascularization. The mean follow-up period was 2.5 ± 0.9 years. The combined primary outcome occurred in 26 patients (11.2%). Calcium score (HR 1.16; 95% CI 1.02-1.31, P = 0.023 per 100 Agatston unit increase), the presence of coronary artery disease (CAD) on CTCA (non-obstructive CAD, HR 4.52; 95% CI 1.30-15.73, P = 0.018; obstructive CAD, HR 17.00; 95% CI 4.60-62.85, P < 0.001), and ≥3 segments with non-calcified plaque (HR 3.30; 95% CI 1.24-8.76, P = 0.017) were significant univariable predictors of the primary outcome. CTCA was the only significant multivariable predictor of adverse outcome.

CONCLUSIONS

The presence of CAD assessed by CTCA is a strong predictor of adverse events in patients with troponin-negative acute chest pain and could potentially be used as an alternative, non-invasive risk stratifier in patients with inconclusive exercise tests.

Clinical implications of the coronary artery calcium score in Japanese patients

Coronary artery calcification (CAC) is a well-established surrogate marker of the total burden of coronary atherosclerosis. The CAC score, as measured on coronary computed tomography (CT), is associated with the prevalence of coronary artery disease (CAD) as well as cardiovascular morbidity and mortality. The CAC score is used to reclassify coronary risks in asymptomatic individuals with intermediate risks. However, there are few clinical data regarding the usefulness of the CAC score for identifying high-risk Japanese patients. In this review article, we describe our previous studies of the prognostic value of the CAC score in patients with proven or suspected CAD. In addition, we reanalyzed our previous data for 723 patients with suspected CAD and found both all-cause and cardiovascular disease mortality to be significantly higher among the patients with a CAC score of ≥100 than among those with a CAC score of ＜100. Several studies from Japan have also shown that the CAC score is associated with the prevalence of obstructive CAD, as demonstrated on invasive coronary angiography or stress myocardial perfusion imaging. Furthermore, the CAC score provides useful information for performing coronary CT angiography, as asymptomatic patients without CAC are expected to have favorable outcomes. In contrast, the diagnostic accuracy is decreased in patients with a high CAC score (＞400 or 600). In conclusion, the CAC score may have useful clinical applications in symptomatic and asymptomatic Japanese individuals. However, further studies are required to evaluate the prognostic value of this parameter for predicting cardiovascular morbidity and mortality in population-based analyses of asymptomatic Japanese subjects.

Role of CT angiography for detection of coronary atherosclerosis

As laparoscopic surgery is replacing open surgery, similarly computed tomography angiography is replacing invasive conventional cardiac angiography. In the last century, marvelous efforts in research have improved strategies for cure, diagnosis and prevention of fatal human diseases; however, coronary artery disease, as the most prevalent cause of mortality and morbidity in the world, has remained a great challenge. Due to advancements in technology and research, it has become more simple and robust to diagnose and treat coronary artery disease (CAD) with minimal or no intervention, promising to not only diagnosis at an early stage but potential prevention altogether. While most with obvious CAD can be diagnosed easily and quickly with ECG, those identified as 'low risk' require more extensive testing to diagnose or rule out CAD. For example in emergency departments, low-risk patients with chest pain are diagnosed solely depending on history, ECG and blood testing for biomarkers. This approach has resulted in either delayed or miss-diagnosis of Acute coronary syndrome. To prevent this, many emergency departments now use protocols for low-risk heart patients that include cardiac stress tests and/or CT heart imaging. This review provides an overview of the current literature on the value of Computed tomography angiography and discusses how prognostic information obtained with Computed tomography angiography can be used to further integrate the technique into clinical practice.

Coronary computed tomographic angiography in the emergency room: state of the art

Chest pain is a common complaint in the emergency department often necessitating testing to exclude underlying obstructive coronary artery disease. While the traditional evaluation of patients with suspected acute coronary syndrome often consists of serial electrocardiograms and cardiac biomarkers, followed by selective use of stress testing for further risk stratification, this approach is costly and inefficient. Recently, coronary computed tomographic angiography (CTA) has offered an alternative approach with a high sensitivity and negative predictive value to exclude obstructive coronary artery disease that can rapidly identify patients with low rates of downstream major adverse cardiac events. In this review, the authors provide an overview of available data on the use of CTA for evaluating acute chest pain, while emphasizing its advantages and disadvantages compared to existing strategies. In addition, we provide a suggested algorithm to identify how CTA can be incorporated into the evaluation of acute chest pain and discuss tips for successful implementation of CTA in the emergency department.