Prevalence and extent of obstructive coronary artery disease in patients with zero or low calcium score undergoing 64-slice cardiac multidetector computed tomography for evaluation of a chest pain syndrome

Coronary atherosclerosis among symptomatic patients with zero coronary artery calcium score in computed tomography coronary angiography

BACKGROUND

Computed tomographic coronary angiography has been recognized as a reliable imaging modality with excellent negative predictive value and a good negative likelihood ratio to exclude coronary artery disease in stable, symptomatic patients with intermediate or high risk. 1) Coronary calcium scoring has been extensively shown to be an invaluable tool to exclude the presence of coronary artery disease in low-risk patients. 2) Our aim was to identify the presence and extent of coronary atherosclerosis in computed tomographic coronary angiography in stable symptomatic patients with a zero Coronary Calcium score.

RESULTS

Three hundred and eighty-three (383) consecutive patients aged ≥ 18 years fulfilling the criteria were enrolled as of January 1, 2021; 165 (43.1%) were male and 218 (56.9%) were female, with a mean age of 57.8 ± 4.9 years and a zero coronary artery calcium score. Two hundred and twenty-six (226) (59.0%) were hypertensive, followed by 125 (32.6%) who were smokers, and 117 (30.5%) who were diabetic. The frequency of atherosclerotic plaque in coronary arteries was 34 (8.9%), with 16 (47.1%) being male and 18 (52.9%) being female. The mean age of patients with atherosclerosis was 54.9 ± 3.3 years; among them, 13 (38.2%) were between the ages of 45 and 54, and 10 (29.4%) were between the ages of 55 and 64. Nineteen (19) (55.9%) were hypertensive, followed by 10 (29.4%) with dyslipidemia. Twenty-three (23) (67.6%) had non-obstructive plaque, and 11 (32.3%) had obstructive plaque. In the subgroup of patients with non-obstructive plaque, 13 (56.5%) were hypertensive, 8 (34.8%) were diabetic, and 16 (69.6%) had single vessel disease, while among patients with obstructive plaque, 6 (54.5%) were hypertensive, 5 (45.5%) were smokers, and all of them had single vessel disease. The most affected artery was the left anterior descending artery.

CONCLUSION

As the frequency of atherosclerotic plaque in patients with a zero coronary calcium score is relatively high, computed tomographic coronary angiography is indicated in stable, symptomatic patients with a lower likelihood of coronary artery disease.

Nephrolithiasis is associated with the severity of coronary artery calcification, but not with coronary artery stenosis

PURPOSE

Emerging data have indicated that nephrolithiasis is possibly associated with subclinical coronary artery disease (CAD). Considering that a significant proportion of obstructive CAD in non-elderly individuals occurs in those without detectable calcium score (CACS), this study aimed to investigate whether nephrolithiasis is still associated with CAD as assessed by coronary computed tomography (CT)-derived luminal stenosis [using Gensini score (GS)].

METHODS

A total of 1170 asymptomatic adults without known CAD who underwent health examinations were recruited. Nephrolithiasis was assessed using abdominal ultrasonography (US). Individuals with a self-reported stone history, but no evidence of nephrolithiasis were excluded. The CACS and GS were measured using 256-slice coronary CT.

RESULTS

Nearly half of these patients had a CACS > 0 (48.1%), and a higher prevalence of nephrolithiasis was observed than in those who had zero CACS (13.1% vs. 9.7%). However, no significant intergroup difference in GS was detected. A greater proportion of stone formers than non-stone formers had a higher risk category, whereas no significant difference was noted in Gensini category. Multiple linear regression analyses showed that the CACS independently predicted the presence of nephrolithiasis after adjustment. Importantly, we found that stone formers had a nearly threefold higher risk than non-stone formers of developing severe coronary calcification (CAC > 400).

CONCLUSIONS

Nephrolithiasis was significantly associated with coronary artery calcification presence and severity, but not coronary luminal stenosis in patients without known CAD. Accordingly, the relationship between stone disease and CAD remains controversial, and additional studies are imperative to validate these findings.

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.

Association of coronary artery calcium score with qualitatively and quantitatively assessed adverse plaque on coronary CT angiography in the SCOT-HEART trial

AIMS

Coronary artery calcification is a marker of cardiovascular risk, but its association with qualitatively and quantitatively assessed plaque subtypes is unknown.

METHODS AND RESULTS

In this post-hoc analysis, computed tomography (CT) images and 5-year clinical outcomes were assessed in SCOT-HEART trial participants. Agatston coronary artery calcium score (CACS) was measured on non-contrast CT and was stratified as zero (0 Agatston units, AU), minimal (1-9 AU), low (10-99 AU), moderate (100-399 AU), high (400-999 AU), and very high (≥1000 AU). Adverse plaques were investigated by qualitative (visual categorization of positive remodelling, low-attenuation plaque, spotty calcification, and napkin ring sign) and quantitative (calcified, non-calcified, low-attenuation, and total plaque burden; Autoplaque) assessments. Of 1769 patients, 36% had a zero, 9% minimal, 20% low, 17% moderate, 10% high, and 8% very high CACS. Amongst patients with a zero CACS, 14% had non-obstructive disease, 2% had obstructive disease, 2% had visually assessed adverse plaques, and 13% had low-attenuation plaque burden >4%. Non-calcified and low-attenuation plaque burden increased between patients with zero, minimal, and low CACS (P < 0.001), but there was no statistically significant difference between those with medium, high, and very high CACS. Myocardial infarction occurred in 41 patients, 10% of whom had zero CACS. CACS >1000 AU and low-attenuation plaque burden were the only predictors of myocardial infarction, independent of obstructive disease, and 10-year cardiovascular risk score.

CONCLUSION

In patients with stable chest pain, zero CACS is associated with a good but not perfect prognosis, and CACS cannot rule out obstructive coronary artery disease, non-obstructive plaque, or adverse plaque phenotypes, including low-attenuation plaque.

Computed tomography angiography versus Agatston score for diagnosis of coronary artery disease in patients with stable chest pain: individual patient data meta-analysis of the international COME-CCT Consortium

OBJECTIVES

There is conflicting evidence about the comparative diagnostic accuracy of the Agatston score versus computed tomography angiography (CTA) in patients with suspected obstructive coronary artery disease (CAD).

PURPOSE

To determine whether CTA is superior to the Agatston score in the diagnosis of CAD.

METHODS

In total 2452 patients with stable chest pain and a clinical indication for invasive coronary angiography (ICA) for suspected CAD were included by the Collaborative Meta-analysis of Cardiac CT (COME-CCT) Consortium. An Agatston score of > 400 was considered positive, and obstructive CAD defined as at least 50% coronary diameter stenosis on ICA was used as the reference standard.

RESULTS

Obstructive CAD was diagnosed in 44.9% of patients (1100/2452). The median Agatston score was 74. Diagnostic accuracy of CTA for the detection of obstructive CAD (81.1%, 95% confidence interval [CI]: 77.5 to 84.1%) was significantly higher than that of the Agatston score (68.8%, 95% CI: 64.2 to 73.1%, p < 0.001). Among patients with an Agatston score of zero, 17% (101/600) had obstructive CAD. Diagnostic accuracy of CTA was not significantly different in patients with low to intermediate (1 to < 100, 100-400) versus moderate to high Agatston scores (401-1000, > 1000).

CONCLUSIONS

Results in our international cohort show CTA to have significantly higher diagnostic accuracy than the Agatston score in patients with stable chest pain, suspected CAD, and a clinical indication for ICA. Diagnostic performance of CTA is not affected by a higher Agatston score while an Agatston score of zero does not reliably exclude obstructive CAD.

KEY POINTS

• CTA showed significantly higher diagnostic accuracy (81.1%, 95% confidence interval [CI]: 77.5 to 84.1%) for diagnosis of coronary artery disease when compared to the Agatston score (68.8%, 95% CI: 64.2 to 73.1%, p < 0.001). • Diagnostic performance of CTA was not affected by increased amount of calcium and was not significantly different in patients with low to intermediate (1 to <100, 100-400) versus moderate to high Agatston scores (401-1000, > 1000). • Seventeen percent of patients with an Agatston score of zero showed obstructive coronary artery disease by invasive angiography showing absence of coronary artery calcium cannot reliably exclude coronary artery disease.

The Diagnostic and Prognostic Value of Coronary Calcium Scoring in Stable Chest Pain Patients: A Narrative Review

Background  Non-contrast computed tomography (CT) scanning allows for reliable coronary calcium score (CCS) calculation at a low radiation dose and has been well established as marker to assess the future risk of coronary artery disease (CAD) events in asymptomatic individuals. However, the diagnostic and prognostic value in symptomatic patients remains a matter of debate. This narrative review focuses on the available evidence for CCS in patients with stable chest pain complaints.

Method  PubMed, Embase, and Web of Science were searched for literature using search terms related to three overarching categories: CT, symptomatic chest pain patients, and coronary calcium. The search resulted in 42 articles fulfilling the inclusion and exclusion criteria: 27 articles (n = 38 137 patients) focused on diagnostic value and 23 articles (n = 44 683 patients) on prognostic value of CCS. Of these, 10 articles (n = 21 208 patients) focused on both the diagnostic and prognostic value of CCS.

Results  Between 22 and 10 037 patients were included in the studies on the diagnostic and prognostic value of CCS, including 43 % and 51 % patients with CCS 0. The most evidence is available for patients with a low and intermediate pre-test probability (PTP) of CAD. Overall, the prevalence of obstructive CAD (OCAD, defined as a luminal stenosis of ≥ 50 % in any of the coronary arteries) as determined with CT coronary angiography in CCS 0 patients, was 4.4 % (n = 703/16 074) with a range of 0–26 % in individual studies. The event rate for major adverse cardiac events (MACE) ranged from 0 % to 2.1 % during a follow-up of 1.6 to 6.8 years, resulting in a high negative predictive value for MACE between 98 % and 100 % in CCS 0 patients. At increasing CCS, the OCAD probability and MACE risk increased. OCAD was present in 58.3 % (n = 617/1058) of CCS > 400 patients with percentages ranging from 20 % to 94 % and MACE occurred in 16.7 % (n = 175/1048) of these patients with percentages ranging from 6.9 % to 50 %.

Conclusion  Accumulating evidence shows that OCAD is unlikely and the MACE risk is very low in symptomatic patients with CCS 0, especially in those with low and intermediate PTPs. This suggests a role of CCS as a gatekeeper for additional diagnostic testing. Increasing CCS is related to an increasing probability of OCAD and risk of cardiac events. Additional research is needed to assess the value of CCS in women and patient management in a primary healthcare setting.

Key Points:  

Citation Format

Association of Age With the Diagnostic Value of Coronary Artery Calcium Score for Ruling Out Coronary Stenosis in Symptomatic Patients

Importance

The diagnostic value is unclear of a 0 coronary artery calcium (CAC) score to rule out obstructive coronary artery disease (CAD) and near-term clinical events across different age groups.

Objective

To assess the diagnostic value of a CAC score of 0 for reducing the likelihood of obstructive CAD and to assess the implications of such a CAC score and obstructive CAD across different age groups.

Design, Setting, and Participants

This cohort study obtained data from the Western Denmark Heart Registry and had a median follow-up time of 4.3 years. Included patients were aged 18 years or older who underwent computed tomography angiography (CTA) between January 1, 2008, and December 31, 2017, because of symptoms that were suggestive of CAD. Data analysis was performed from April 5 to July 7, 2021.

Exposures

Obstructive CAD, which was defined as 50% or more luminal stenosis.

Main Outcomes and Measures

Proportion of individuals with obstructive CAD who had a CAC score of 0. Risk-adjusted diagnostic likelihood ratios were used to assess the diagnostic value of a CAC score of 0 for reducing the likelihood of obstructive CAD beyond clinical variables. Risk factors associated with myocardial infarction and death were estimated.

Results

A total of 23 759 symptomatic patients, of whom 12 771 (54%) had a CAC score of 0, were included. This cohort had a median (IQR) age of 58 (49-65) years and was primarily composed of women (13 160 [55%]). Overall, the prevalence of obstructive CAD was relatively low across all age groups, ranging from 3% (39 of 1278 patients) in those who were younger than 40 years to 8% (52 of 619) among those who were 70 years or older. In patients with obstructive CAD, 14% (725 of 5043) had a CAC score of 0, and the prevalence varied across age groups from 58% (39 of 68) among those who were younger than 40 years, 34% (192 of 562) among those aged 40 to 49 years, 18% (268 of 1486) among those aged 50 to 59 years, 9% (174 of 1963) among those aged 60 to 69 years, to 5% (52 of 964) among those who were 70 years or older. The added diagnostic value of a CAC score of 0 decreased at a younger age, with a risk factor-adjusted diagnostic likelihood ratio of a CAC score of 0 ranging from 0.68 (approximately 32% lower likelihood of obstructive CAD than expected) in those who were younger than 40 years to 0.18 (approximately 82% lower likelihood than expected) in those who were 70 years or older. The presence of obstructive vs nonobstructive CAD among those with a CAC score of 0 was associated with a multivariable adjusted hazard ratio of 1.51 (95% CI, 0.98-2.33) for myocardial infarction and all-cause death; however, this hazard ratio varied from 1.80 (95% CI, 1.02-3.19) in those who were younger than 60 years to 1.24 (95% CI, 0.64-2.39) in those who were 60 years or older.

Conclusions and Relevance

This cohort study found that the diagnostic value of a CAC score of 0 to rule out obstructive CAD beyond clinical variables was dependent on age, with the added diagnostic value being smaller for younger patients. In symptomatic patients who were younger than 60 years, a sizable proportion of obstructive CAD occurred among those without CAC and was associated with an increased risk of myocardial infarction and all-cause death.

Coronary artery calcium score and risk of cardiovascular events without established coronary artery disease: a systemic review and meta-analysis

BACKGROUND

Coronary artery calcium (CAC) is an indicator of atherosclerosis, and the CAC score is a useful noninvasive assessment of coronary artery disease.

OBJECTIVE

To compare the risk of cardiovascular outcomes in patients with CAC > 0 versus CAC = 0 in asymptomatic and symptomatic population in patients without an established diagnosis of coronary artery disease.

METHODS

A systematic search of electronic databases was conducted until January 2018 for any cohort study reporting cardiovascular events in patients with CAC > 0 compared with absence of CAC.

RESULTS

Forty-five studies were included with 192 080 asymptomatic 32 477 symptomatic patients. At mean follow-up of 11 years, CAC > 0 was associated with an increased risk of major adverse cardiovascular and cerebrovascular events (MACE) compared to a CAC = 0 in asymptomatic arm [pooled risk ratio (RR) 4.05, 95% confidence interval (CI) 2.91-5.63, P < 0.00001, I2 = 80%] and symptomatic arm (pooled RR 6.06, 95% CI 4.23-8.68, P < 0.00001, I2 = 69%). CAC > 0 was also associated with increased risk of all-cause mortality in symptomatic population (pooled RR 7.94, 95% CI 2.61-24.17, P < 0.00001, I2 = 85%) and in asymptomatic population CAC > 0 was associated with higher all-cause mortality (pooled RR 3.23, 95% CI 2.12-4.93, P < 0.00001, I2 = 94%). In symptomatic population, revascularization in CAC > 0 was higher (pooled RR 15, 95% CI 6.66-33.80, P < 0.00001, I2 = 72) compared with CAC = 0. Additionally, CAC > 0 was associated with more revascularization in asymptomatic population (pooled RR 5.34, 95% CI 2.06-13.85, P = 0.0006, I2 = 93). In subgroup analysis of asymptomatic population by gender, CAC > 0 was associated with higher MACE (RR 6.39, 95% CI 3.39-12.84, P < 0.00001).

CONCLUSION

Absence of CAC is associated with low risk of cardiovascular events compared with any CAC > 0 in both asymptomatic and symptomatic population without coronary artery disease.

Prevalence and associated risk factors of coronary artery disease in patients with a zero coronary calcium score

PURPOSE

A zero coronary calcium score (CCS) is not able to provide a definite exclusion for coronary artery disease (CAD). The goal of this study was to determine the prevalence and associated cardiovascular risk factors of CAD in patients with zero CCS.

METHODS

Six hundred thirteen patients with zero CCS referred to coronary calcium score analysis (CCSA) and coronary computed tomography angiography (CCTA) with suspicion of CAD were included. The descriptive, univariate, and multivariate analyses were used to determine the prevalence and predictors of CAD presence.

RESULTS

Among 613 patients, 17 patients (2.7%) have NCCP, and obstructive CAD was found in 3 patients (0.48%). Multivariate analysis revealed that male gender and older age (≥50 years) were significantly associated with the presence of noncalcified coronary plaques (NCCP) (p < 0.05). The receiver operating characteristic (ROC) curve analysis showed that the male gender and older age (≥50 years) model had 70.6% sensitivity and 84.2% specificity for predicting NCCP.

CONCLUSION

A non-negligible portion of patients with zero CCS had CAD. Male gender and older age (≥50 years) were independently associated with NCCP. Due to the high specificity value (84.2%) and negative predictive value (99.0%) of the male gender and older age (≥50 years) model, selective use of CCTA is recommended in <50 years old female patients to avoid unnecessary radiation exposure.

Gender Differences in the Atherosclerosis Profile by Coronary CTA in Coronary Artery Calcium Score Zero Patients

Background: The coronary artery calcium score (CACS) is a powerful tool for cardiovascular risk stratification. Coronary computed tomography angiography (CTA) allows for a more distinct analysis of atherosclerosis. The aim of the study was to assess gender differences in the atherosclerosis profile of CTA in patients with a CACS of zero. Methods: A total of 1451 low- to intermediate-risk patients (53 ± 11 years; 51% females) with CACS <1.0 Agatston units (AU) who underwent CTA and CACS were included. Males and females were 1:1 propensity score-matched. CTA was evaluated for stenosis severity (Coronary Artery Disease - Reporting and Data System (CAD-RADS) 0-5: minimal <25%, mild 25-49%, moderate 50-69%, severe ≥70%), mixed-plaque burden (G-score), and high-risk plaque (HRP) criteria (low-attenuation plaque, spotty calcification, napkin-ring sign, and positive remodeling). All-cause mortality, cardiovascular mortality, and major cardiovascular events (MACEs) were collected. Results: Among the patients, 88.8% had a CACS of 0 and 11.2% had an ultralow CACS of 0.1-0.9 AU. More males than females (32.1% vs. 20.3%; p < 0.001) with a CACS of 0 had atherosclerosis, while, among those with an ultralow CACS, there was no difference (88% vs. 87.1%). Nonobstructive CAD (25.9% vs. 16.2%; p < 0.001), total plaque burden (2.2 vs. 1.4; p < 0.001), and HRP were found more often in males (p < 0.001). After a follow-up of mean 6.6 ± 4.2 years, all-cause mortality was higher in females (3.5% vs. 1.8%, p = 0.023). Cardiovascular mortality and MACEs were low (0.2% vs. 0%; p = 0.947 and 0.3% vs. 0.6%; p = 0.790) for males vs. females, respectively. Females were more often symptomatic for chest pain (70% vs. 61.6%; p = 0.004). (4) Conclusions: In patients with a CACS of 0, males had a higher prevalence of atherosclerosis, a higher noncalcified plaque burden, and more HRP criteria. Nonetheless, females had a worse long-term outcome and were more frequently symptomatic.

Prognostic Value of Coronary CT Angiography for Predicting Poor Cardiac Outcome in Stroke Patients without Known Cardiac Disease or Chest Pain: The Assessment of Coronary Artery Disease in Stroke Patients Study

Objective

To assess the incremental prognostic value of coronary computed tomography angiography (CCTA) in comparison to a clinical risk model (Framingham risk score, FRS) and coronary artery calcium score (CACS) for future cardiac events in ischemic stroke patients without chest pain.

Materials and Methods

This retrospective study included 1418 patients with acute stroke who had no previous cardiac disease and underwent CCTA, including CACS. Stenosis degree and plaque types (high-risk, non-calcified, mixed, or calcified plaques) were assessed as CCTA variables. High-risk plaque was defined when at least two of the following characteristics were observed: low-density plaque, positive remodeling, spotty calcification, or napkin-ring sign. We compared the incremental prognostic value of CCTA for major adverse cardiovascular events (MACE) over CACS and FRS.

Results

The prevalence of any plaque and obstructive coronary artery disease (CAD) (stenosis ≥ 50%) were 70.7% and 30.2%, respectively. During the median follow-up period of 48 months, 108 patients (7.6%) experienced MACE. Increasing FRS, CACS, and stenosis degree were positively associated with MACE (all p < 0.05). Patients with high-risk plaque type showed the highest incidence of MACE, followed by non-calcified, mixed, and calcified plaque, respectively (log-rank p < 0.001). Among the prediction models for MACE, adding stenosis degree to FRS showed better discrimination and risk reclassification compared to FRS or the FRS + CACS model (all p < 0.05). Furthermore, incorporating plaque type in the prediction model significantly improved reclassification (integrated discrimination improvement, 0.08; p = 0.023) and showed the highest discrimination index (C-statistics, 0.85). However, the addition of CACS on CCTA with FRS did not add to the prediction ability for MACE (p > 0.05).

Conclusion

Assessment of stenosis degree and plaque type using CCTA provided additional prognostic value over CACS and FRS to risk stratify stroke patients without prior history of CAD better.

Prognostic significance of subtle coronary calcification in patients with zero coronary artery calcium score: From the CONFIRM registry

BACKGROUND AND AIMS

The Agatston coronary artery calcium score (CACS) may fail to identify small or less dense coronary calcification that can be detected on coronary CT angiography (CCTA). We investigated the prevalence and prognostic importance of subtle calcified plaques on CCTA among individuals with CACS 0.

METHODS

From the prospective multicenter CONFIRM registry, we evaluated patients without known CAD who underwent CAC scan and CCTA. CACS was categorized as 0, 1-10, 11-100, 101-400, and >400. Patients with CACS 0 were stratified according to the visual presence of coronary plaques on CCTA. Plaque composition was categorized as non-calcified (NCP), mixed (MP) and calcified (CP). The primary outcome was a major adverse cardiac event (MACE) which was defined as death and myocardial infarction.

RESULTS

Of 4049 patients, 1741 (43%) had a CACS 0. NCP and plaques that contained calcium (MP or CP) were detected by CCTA in 110 patients (6% of CACS 0) and 64 patients (4% of CACS 0), respectively. During a 5.6 years median follow-up (IQR 5.1-6.2 years), 413 MACE events occurred (13%). Patients with CACS 0 and MP/CP detected by CCTA had similar MACE risk compared to patients with CACS 1-10 (p = 0.868). In patients with CACS 0, after adjustment for risk factors and symptom, MP/CP was associated with an increased MACE risk compared to those with entirely normal CCTA (HR 2.39, 95% CI [1.09-5.24], p = 0.030).

CONCLUSIONS

A small but non-negligible proportion of patients with CACS 0 had identifiable coronary calcification, which was associated with increased MACE risk. Modifying CAC image acquisition and/or scoring methods could improve the detection of subtle coronary calcification.

Natural course of coronary artery calcium progression in Asian population with an initial score of zero

Background

We aimed to investigate the natural course of coronary artery calcium progression in an Asian population with a baseline coronary artery calcium (CAC) score of zero, and to determine subclinical coronary atherosclerosis.

Methods

Four hundred fifty-nine subjects with at least two CAC scans with an initial score of zero were included. CAC progression (+) was defined by the development of any CAC (i.e., CAC > 0) during subsequent CT scans. Clinical characteristics and Framingham risk profiles were also recorded.

Results

Among 459 subjects, 106 (23.09%) experienced CAC progression during the average follow-up period of 5.71 ± 2.68 years. Older age, male gender, HDL-C, total cholesterol and higher Framingham risk score were independently associated with CAC progression. Framingham risk score had the better discriminative ability (AUC = 0.660) to predict CAC progression compared to the other parameters with a sensitivity of 75.24% and specificity of 53.95%. For the double zero score with coronary artery atherosclerosis prediction, older age, triglycerides, hypertension, and Framingham risk score were significantly associated with these events. Among these parameters, Framingham risk score may be a relatively acceptable parameter with high negative predictive (NPV = 96.4%) value to rule out double zero score with obstructive coronary artery atherosclerosis scenario with an optimum cut-off value of <16.9 (AUC =0.652, sensitivity of 57.69%; specificity of 68.82%).

Conclusions

A baseline zero CAC score in asymptomatic Chinese population with low to intermediate risk have a low incidence for CAC progression within the 5-years period. For CAC progression prediction, Framingham risk score with the cutoff < 11.1 may help confirm subjects at low risk to improve cardiovascular risk stratification and reclassification in the field of preventive cardiology.

Long-Term Prognostic Value of Coronary Computed Tomography Angiography in an Asymptomatic Elderly Population

Background

The prognostic value of coronary computed tomographic angiography (CCTA) for evaluating coronary artery disease in asymptomatic older adults is controversial. We investigated the prognostic value of CCTA in community‐dwelling elderly Koreans.

Methods and Results

Participants (n=470; mean age: 75.1±7.3 years) who underwent CCTA were enrolled from KLoSHA (Korean Longitudinal Study on Health and Aging), a community‐based prospective cohort. Using CCTA, coronary artery disease was classified as normal, nonobstructive, or obstructive according to the presence of 0%, <50%, or ≥50% stenosis, respectively. Coronary artery calcium scores were investigated together with Framingham risk score, atherosclerotic cardiovascular disease score, and individual risk factors. Major adverse cardiac events (MACE) were defined as a composite of cardiac event–related death or nonfatal myocardial infarction. During a median follow‐up of 8.2 years (interquartile range: 7.7–10.1 years), MACE occurred in 24 participants (5.1%). Compared with the normal group, participants in the obstructive group showed higher incidence of MACE (hazard ratio: 5.65; 95% CI, 1.22–26.16; P=0.027), whereas there were no significant differences in MACE between the normal and nonobstructive groups. The 8‐year event‐free survival rates were 98.1±1.1%, 94.9±1.6%, and 81.7±4.8% in the normal, nonobstructive, and obstructive groups, respectively. Compared with the Framingham risk score and coronary artery calcium score model, CCTA improved risk prediction by C‐index (from 0.698 to 0.749) and category‐free net reclassification index (0.478; P=0.022).

Conclusions

CCTA showed better long‐term prognostic value for MACE than coronary artery calcium score in this asymptomatic older population.

Point of Care Clinical Risk Score to Improve the Negative Diagnostic Utility of an Agatston Score of Zero: Averting the Need for Coronary Computed Tomography Angiography

BACKGROUND

Coronary artery calcification is a marker of underlying atherosclerotic vascular disease. The absence of coronary artery calcification is associated with a low prevalence of obstructive coronary artery disease (CAD), but it cannot be ruled out completely. We sought to develop a clinical tool that can be added to Agatston score of zero to rule out obstructive CAD with high accuracy.

METHODS

We developed a clinical score retrospectively from a cohort of 4903 consecutive patients with an Agatston score of zero. Patients with prior diagnosis of CAD, coronary percutaneous coronary intervention, or surgical revascularization were excluded. Obstructive CAD was defined as any epicardial vessel diameter narrowing of ≥50%. The score was validated using an external cohort of 4290 patients with an Agatston score of zero from a multinational registry.

RESULTS

The score consisted of 7 variables: age, sex, typical chest pain, dyslipidemia, hypertension, family history, and diabetes mellitus. The model was robust with an area under the curve of 0.70 (95% CI, 0.65-0.76) in the derivation cohort and 0.69 (95% CI, 0.65-0.72) in the validation cohort. Patients were divided into 3 risk groups based on the score: low (≤6), intermediate (7-13), and high (≥14). Patients who score ≤6 have a negative likelihood ratio of 0.42 for obstructive CAD, whereas those who score ≥14 have a positive likelihood ratio of >5.5 for obstructive CAD. The outcome was ruled out in >98% of patients with a score ≤6 in the validation cohort.

CONCLUSIONS

We developed a score that may be used to identify the likelihood of obstructive CAD in patients with an Agatston score of zero, which may be used to direct the need for additional testing. However, the results of this retrospective analysis are hypothesis generating and before clinical implementation should be validated in a trial with a prospectively collected data.

Predictors of Severe or Moderate Coronary Artery Disease in Asymptomatic Individuals with Extremely Low Coronary Calcium Scores

PURPOSE

To evaluate predictors of severe or moderate coronary artery disease (CAD) in individuals with zero or very low (<10) coronary artery calcium (CAC) scores.

MATERIALS AND METHODS

The 1175 asymptomatic persons with zero or very low (<10) CAC scores were analyzed for CAD stenosis using coronary computed tomography angiography. Moderate and severe CADs were defined as having more than 50% and more than 70% stenosis in any of the major coronary arteries, respectively. Age, gender, body mass index, hypertension, type II diabetes, dyslipidemia, lipid profile, creatinine, and smoking status were evaluated as predictors for moderate and severe CAD.

RESULTS

In the study population, moderate and severe CADs were found in 7.5% and 3.3%, respectively. Among evaluated risk factors, age [odds ratio (OR) 1.04, 95% confidence interval (CI) 1.02-1.07, p<0.001], current smoking status (OR 3.12, 95% CI 1.82-5.34, p<0.001), and CAC 1-9 (OR 1.80, 95% CI 1.08-3.00, p=0.024) were significantly associated with moderate CAD. Meanwhile, age (OR 1.05, 95% CI 1.02-1.08, p=0.003), low high density lipoprotein (HDL) (OR 0.96, 95% CI 0.93-0.99, p=0.003), and current smoking status (OR 2.34, 95% CI 1.14-5.30, p=0.022) were found to be significantly associated with severe CAD. Improvement of discrimination power for predicting severe CAD was observed when smoking and HDL cholesterol were serially added into the age model.

CONCLUSION

Smoking showed significant correlations with moderate or severe CAD, and low HDL cholesterol also proved to be a predictor of severe CAD in asymptomatic individuals with extremely low CAC scores.

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.

Atherosclerotic Plaque in Patients with Zero Calcium Score at Coronary Computed Tomography Angiography

Background

In view of the high mortality for cardiovascular diseases, it has become necessary to stratify the main risk factors and to choose the correct diagnostic modality. Studies have demonstrated that a zero calcium score (CS) is characteristic of a low risk for cardiovascular events. However, the prevalence of individuals with coronary atherosclerotic plaques and zero CS is conflicting in the specialized literature.

Objective

To evaluate the frequency of patients with coronary atherosclerotic plaques, their degree of obstruction and associated factors in patients with zero CS and indication for coronary computed tomography angiography (CCTA).

Methods

This is a cross-sectional, prospective study with 367 volunteers with zero CS at CCTA in four diagnostic imaging centers in the period from 2011 to 2016. A significance level of 5% and 95% confidence interval were adopted.

Results

The frequency of atherosclerotic plaque in the coronary arteries in 367 patients with zero CS was 9.3% (34 individuals). In this subgroup, mean age was 52 ± 10 years, 18 (52.9%) were women and 16 (47%) had significant coronary obstructions (> 50%), with involvement of two or more segments in 4 (25%) patients. The frequency of non-obese individuals (90.6% vs 73.9%, p = 0.037) and alcohol drinkers (55.9% vs 34.8%, p = 0.015) was significantly higher in patients with atherosclerotic plaques, with an odds ratio of 3.4 for each of this variable.

Conclusions

The frequency of atherosclerotic plaque with zero CS was relatively high, indicating that the absence of calcification does not exclude the presence of plaques, many of which obstructive, especially in non-obese subjects and alcohol drinkers.

Prevalence of obstructive coronary artery disease and prognosis in patients with stable symptoms and a zero-coronary calcium score

AIMS

CT calcium scoring (CTCS) and CT cardiac angiography (CTCA) are widely used in patients with stable chest pain to exclude significant coronary artery disease (CAD). We aimed to resolve uncertainty about the prevalence of obstructive coronary artery disease and long-term outcomes in patients with a zero-calcium score (ZCS).

METHODS AND RESULTS

Consecutive patients with stable cardiac symptoms referred for CTCS or CTCS and CTCA from chest pain clinics to a tertiary cardiothoracic centre were prospectively enrolled. In those with a ZCS, the prevalence of obstructive CAD on CTCA was determined. A follow-up for all-cause mortality was obtained from the NHS tracer service. A total of 3914 patients underwent CTCS of whom 2730 (69.7%) also had a CTCA. Half of the patients were men (50.3%) with a mean age of 56.9 years. Among patients who had both procedures, a ZCS was present in 52.2%, with a negative predictive value of 99.5% for excluding ≥70% stenosis on CTCA. During a mean follow-up of 5.2 years, the annual event rate was 0.3% for those with ZCS compared with 1.2% for CS ≥1. The presence of non-calcified atheroma on CTCA in patients with ZCS did not affect the prognostic value (P = 0.98).

CONCLUSION

In patients with stable symptoms and a ZCS, obstructive CAD is rare, and prognosis over the long-term is excellent, regardless of whether non-calcified atheroma is identified. A ZCS could reliably be used as a 'gatekeeper' in this patient cohort, obviating the need for further more expensive tests.

[Myocardial ischaemia detection in women]

Screening of myocardial ischemia refers to the use of one or more diagnostic tests for coronary heart disease with a dual objective of appropriateness and promptness. In women, as compared to men, the accuracy of the different tests is worse. Thus, to overcome this sex-related penalty, we must define a diagnosis strategy based on risk stratification, enabling the identification of patients requiring invasive investigations. This review discusses various non-invasive diagnostic tests focusing on a female-specific approach and defines the use of numerous diagnostic tests with respect to both risk stratification and symptoms.

Coronary Computed Tomography (CT) Angiography as a Predictor of Cardiac and Noncardiac Vascular Events in Asymptomatic Type 2 Diabetics: A 7-Year Population-Based Cohort Study

Background

Type 2 diabetics are at increased risk for vascular events, but the value of further risk stratification for coronary heart disease (CHD) in asymptomatic subjects is unclear. We examined the added value of coronary computed tomography angiography over clinical risk scores (United Kingdom Prospective Diabetes Study), and coronary artery calcium in a population‐based cohort of asymptomatic type 2 diabetics.

Methods and Results

Subjects (n=630) underwent baseline clinical assessment and computed tomography angiography (64‐slice scanner). Plaque site, volume, calcific content, and arterial remodeling were recorded using dedicated software. Coronary, macrovascular, and microvascular‐related events were assessed over 6.6±0.6 (mean±SD) (range 5.4–7.5) years and all CHD events were adjudicated. Discrimination of CHD events (cardiovascular death, myocardial infarction, unstable angina, or new‐onset angina requiring intervention) (n=41) was improved by addition of total plaque burden to the clinical risk and coronary artery calcium scores combined (C=0.789 versus 0.763, P=0.034) and further improved by addition of an angiographic score (C=0.824, P=0.021). Independent predictors of a CHD event were United Kingdom Prospective Diabetes Study risk score (hazard ratio 1.3 per 10% 10‐year risk, P=0.003) and the angiographic score (hazard ratio 3.2 per quartile, P<0.0001). Classification was improved over that by United Kingdom Prospective Diabetes Study and coronary artery calcium scores alone (overall net reclassification improvement 0.24). In subjects with coronary plaque (N=500), mild plaque calcification independently predicted a CHD event (hazard ratio 3.0, P=0.02). Computed tomography angiography predicted combined macrovascular but not microvascular‐related events.

Conclusions

Computed tomography angiography provides additional prognostic information in asymptomatic type 2 diabetics not obtainable from clinical risk assessment and coronary artery calcium alone.

Multimodality Imaging in Coronary Artery Disease: Focus on Computed Tomography

Coronary artery disease (CAD) is the leading cause of mortality worldwide, and various cardiovascular imaging modalities have been introduced for the purpose of diagnosing and determining the severity of CAD. More recently, advances in computed tomography (CT) technology have contributed to the widespread clinical application of cardiac CT for accurate and noninvasive evaluation of CAD. In this review, we focus on imaging assessment of CAD based upon CT, which includes coronary artery calcium screening, coronary CT angiography, myocardial CT perfusion, and fractional flow reserve CT. Further, we provide a discussion regarding the potential implications, benefits and limitations, as well as the possible future directions according to each modality.

Automated Computer-Assisted Diagnosis of Obstructive Coronary Artery Disease in Emergency Department Patients Undergoing 256-Slice Coronary Computed Tomography Angiography for Acute Chest Pain

A 256-slice coronary computed tomography angiography (CCTA) is an accurate method for detection and exclusion of obstructive coronary artery disease (OBS-CAD). However, accurate image interpretation requires expertise and may not be available at all hours. The purpose of this study was to evaluate the usefulness of a fully automated computer-assisted diagnosis (COMP-DIAG) tool for exclusion of OBS-CAD in patients in the emergency department (ED) presenting with chest pain. Three hundred sixty-nine patients in ED without known coronary disease underwent 256-slice CCTA as part of the assessment of chest pain of uncertain origin. COMP-DIAG (CorAnalyzer II) automatically reported presence or exclusion of OBS-CAD (>50% stenosis, ≥1 vessel). Performance characteristics of COMP-DIAG for exclusion and detection of OBS-CAD were determined using expert reading as the reference standard. Seventeen (5%) studies were unassessable by COMP-DIAG software, and 352 patients (1,056 vessels) were therefore available for analysis. COMP-DIAG identified 33% of assessable studies as having OBS-CAD, but the prevalence of OBS-CAD on CCTA was only 18% (66 of 352 patients) by standard expert reading. However, COMP-DIAG correctly identified 61 of the 66 patients (93%) with OBS-CAD with 21 vessels (2%) with OBS-CAD misclassified as negative. In conclusion, compared to expert reading, automated computer-assisted diagnosis using the CorAnalyzer showed high sensitivity but only moderate specificity for detection of obstructive coronary disease in patients in ED who underwent 256-slice CCTA. The high negative predictive value of this computer-assisted algorithm may be useful in the ED setting.

Coronary artery calcium: 0.5 mm slice-thickness reconstruction with adjusted attenuation threshold outperforms 3.0 mm by validating against spatially registered intravascular ultrasound with radiofrequency backscatter

RATIONALE AND OBJECTIVES

Coronary artery calcium (CAC) images can be reconstructed with thinner slice thickness on some modern multidetector-row computed tomography scanners without additional radiation. We hypothesized that the isotropic 0.5-mm CAC reconstruction outperforms the conventional 3.0-mm reconstruction in detecting and quantifying coronary calcium, and we proposed to compare them by validating against spatially registered intravascular ultrasound with radiofrequency backscatter-virtual histology (IVUS-VH).

MATERIALS AND METHODS

Twenty-seven patients were enrolled, and 5976 mm of coronary arteries were analyzed. A semiautomatic software was developed to coregister CAC and IVUS-VH on a detailed slice-by-slice basis. Calcium detection and calcium volume quantification were evaluated and compared using varying calcium attenuation thresholds. Algorithms for deriving individualized optimal threshold and comparable Agatston score on the 0.5-mm reconstruction were developed.

RESULTS

The isotropic 0.5-mm reconstruction achieved significantly higher area under receiver-operating curve than the conventional 3.0-mm reconstruction (0.9 vs. 0.74, P < .001). Using the optimal threshold, the 0.5-mm reconstruction had higher sensitivity (0.79 vs. 0.65), specificity (0.85 vs. 0.77), positive predictive value (0.42 vs. 0.29), and negative predictive value (0.97 vs. 0.94) than the 3.0 mm. Individualized optimal threshold was significantly correlated with the image noise (r = 0.66, P < .001) in the 0.5-mm reconstruction.

CONCLUSIONS

By optimizing the calcium threshold, the 0.5-mm reconstruction is superior to the conventional 3.0-mm in detecting and quantifying calcium, which may improve the clinical value of CAC without additional radiation.

Coronary CT angiography findings based on smoking status: Do ex-smokers and never-smokers share a low probability of developing coronary atherosclerosis?

The relationship of coronary artery disease (CAD) in ex-smokers has not been elucidated, although smoking is considered to be one of the major risk factors of CAD. We investigate subclinical coronary atherosclerosis (SCA) in asymptomatic subjects with coronary computed tomography angiography (CCTA), according to smoking status, and determine whether ex-smokers share a low probability of developing CAD with never-smokers. We retrospectively enrolled 6930 self-referred asymptomatic adults who underwent both coronary artery calcium score (CACS) and CCTA. The prevalence and characteristics of SCA were assessed according to smoking status (never-, ex- and current smokers). After adjusting for variable risk factors, we used multivariate logistic regression for adjusted odds ratios (AOR) of high CACS (>100), SCA (any plaque), significant stenosis (>50 % in luminal stenosis) and each plaque type (non-calcified, mixed and calcified plaque) among the three groups. The prevalence of SCA was highest in the ex-smokers (35.4 %) and the prevalence of significant stenosis in ex-smokers (6.9 %) was as high as in current smokers (6.4 %). However, after adjusting for variable risk factors, SCA was significantly correlated with both ex-smokers (AOR; 1.21) and current smokers (AOR; 1.25), whereas significant stenosis was correlated only with current smokers (AOR; 1.91). The association between SCA and ex-smokers is as strong as with current smokers, although significant stenosis is only correlated with current smokers; thus, not only quitting smoking but also never initiating smoking would be helpful to reduce the progression of the SCA.

Using coronary artery calcification combined with pretest clinical risk assessment as a means of determining investigation and treatment in patients presenting with chest pain in a rural setting

462 patients presenting with chest pain to a rural district general hospital underwent calcium scoring and pretest clinical risk assessment in order to stratify subsequent investigations and treatment was retrospectively reviewed. The patients were followed up for two years and further investigations and outcomes recorded. Of the 206 patients with zero calcium score, 132 patients were immediately discharged from cardiac follow-up with no further investigation on the basis of their calcium score, low pretest risk of coronary artery disease, and no significant incidental findings. After further tests, 267 patients were discharged with no further cardiac therapy, 88 patients were discharged with additional medical therapy, and 19 patients underwent coronary artery by-pass grafting or percutaneous intervention. 164 patients with incidental findings on the chest CT (computed tomography) accompanying calcium scoring were reviewed, of which 88 patients underwent further tests and follow-up for noncardiac causes of chest pain. The correlations between all major risk factors and calcium scores were weak except for a combination of diabetes and hypertension in the male gender (P = 0.012), The use of calcium scoring and pretest risk appeared to reduce the number of unnecessary cardiac investigations in our patients: however, the calcium scoring test produced a high number of incidental findings on the associated CT scans.

Does coronary calcium scoring with a SCORE better predict significant coronary artery stenosis than without? Correlation with computed tomography coronary angiography

OBJECTIVE

To determine effectiveness of coronary artery calcium score (CACS) alone and combined with Systematic Coronary Risk Evaluation (SCORE) in adult patients for significant coronary artery stenosis by using computed tomography coronary angiography (CTCA) as reference standard.

METHODS

Two thousand twenty-one patients with suspected coronary artery disease (CAD) underwent CACS test and CTCA. Patients were examined with dual-source CT and were grouped according to their age, gender, CACS, and estimated SCORE risk. Coronary plaque existence and degree of stenosis were assessed with CTCA. Sensitivity, specificity, and ROC curves were analyzed.

RESULTS

CACS was the single independent variable in estimating relative risk of critical stenosis and had superior outcome when compared with SCORE risk in logistic regression and ROC curve. Area under the ROC curve was greatest in the interval between 50-59 years. When SCORE was combined with CACS in patients with zero CACS, percentage of significant stenosis increased from 1.4% to 7.0% in patients with high or very high SCORE risk, and decreased to 0.9 % in patients with low or moderate SCORE risk.

CONCLUSIONS

CACS combination with SCORE risk predicts coronary artery stenosis. When CACS is zero, CTCA can be performed in patients with high or very high SCORE risk.

Diagnostic efficacy of vessel specific coronary calcium score in detection of coronary artery stenosis

BACKGROUND

Coronary artery calcification which is determined quantitatively by coronary calcium scoring has been known as a sign of coronary stenosis and thus future cardiac events; hence it has been noticed on spotlight of researchers in recent years. Developing different method for early and optimal detection of coronary artery disease (CAD) is really essential as CAD are the first cause of death in population.

OBJECTIVES

To evaluate predictive value of vessel specific coronary artery calcium (CAC) score in predicting obstructive coronary artery disease.

PATIENTS AND METHODS

In this diagnostic test study we evaluated patients with coronary computed tomography angiography (CCTA) and CAC score which had been referred to two referral radiology center in Tehran, Iran and finally we selected 2525 patients in a single and sequential pattern to create a diagnostic study. The whole-heart CAC scores and vessel specific CAC scores were calculated individually for the 4 major epicardial coronary arteries in 2 distinct group; group A ( patients with previous history of CABG) and group B (patients without history of CABG). For evaluation of obstruction tree cut off points were described: 0 > ; at least 1 segment with any kind of stenosis, ≥ 50; at least 1 segment with stenosis ≥ 50, ≥ 70; at least 1 segment with stenosis ≥ 70.

RESULTS

Mean of coronary calcium scores in terms of each coronary artery vessel increase by increasing coronary stenosis grade in group B; LAD, RCA, LCX respectively have mean CAC score 6.06, 6.21 and 5.04 in normal patients and 221.6, 226.7 and 106.6 in patients with complete stenosis. As expected these findings don't work for group A. Also By increasing calcium score cutoff in all four vessels sensitivity decreased and specificity increased but steal LAD had higher sensitivity than other vessels and LM had higher specificity. Thus using calcium score method is useful for ruling out stenosis in LAD while calcium score of LM can predict existence of stenosis in LM. However none of the vessel specific CAC can reach to 100% sensitivity and specificity of CCTA method.

CONCLUSIONS

CCTA is highly superior than vessel specific CAC score thus to minimize patients radiation does maybe we can eliminate CAC scan as a routinely perform procedure at the beginning of the CCTA.

The relationship between gamma-glutamyl transferase levels and coronary plaque burdens and plaque structures in young adults with coronary atherosclerosis

BACKGROUND

Elevated gamma-glutamyl transferase (GGT) levels have been demonstrated to be associated with poor prognoses in patients with coronary artery disease. Coronary computed tomography angiography (CCTA) is a noninvasive imaging modality that may differentiate the structure of coronary plaques. Elevated plaque burdens and noncalcified plaques, detected by CCTA, are important predictors of atherosclerosis in young adults.

HYPOTHESIS

The present study investigated the possible relationship between GGT levels and coronary plaque burdens/structures in young adults with coronary atherosclerosis.

METHODS

CCTA images of 259 subjects were retrospectively examined, and GGT levels were compared between patients with coronary plaques and individuals with normal coronary arteries. Coronary plaques, detected by CCTA, were categorized as noncalcified, calcified, and mixed, according to their structures. The significant independent predictors of coronary atherosclerosis were also analyzed using multivariate logistic regression analysis.

RESULTS

GGT levels were significantly higher in patients with coronary plaque formation than in controls (35.7 ± 14.7 vs 19.6 ± 10.0 U/L; P < 0.001). GGT levels were also positively correlated with the number of plaques; presence of noncalcified plaques; and levels of high-sensitivity C-reactive protein (hs-CRP), hemoglobin A1c, uric acid, and triglycerides. Moreover, smoking and levels of GGT, hs-CRP, uric acid, and low high-density lipoprotein cholesterol were independent predictors of coronary atherosclerosis.

CONCLUSIONS

GGT is an inexpensive and readily available marker that provides additional risk stratification beyond that provided by conventional risk factors for predicting coronary plaque burdens and plaque structures in young adults.

The value of coronary artery calcium score assessed by dual-source computed tomography coronary angiography for predicting presence and severity of coronary artery disease

BACKGROUND

Measuring coronary artery calcium score (CACS) using a dual-source CT scanner is recognized as a major indicator for assessing coronary artery disease. The present study aimed to validate the clinical significance of CACS in predicting coronary artery stenosis and its severity.

MATERIAL/METHODS

This prospective study was conducted on 202 consecutive patients who underwent both conventional coronary angiography and dual-source (256-slice) computed tomography coronary angiography (CTA) for any reason in our cardiac imaging center from March to September 2013. CACS was measured by Agatston algorithm on non-enhanced CT. The severity of coronary artery disease was assessed by Gensini score on conventional angiography.

RESULTS

There was a significant relationship between the number of diseased coronary vessels and mean calcium score, i.e. the mean calcium score was 202.25±450.06 in normal coronary status, 427.50±607.24 in single-vessel disease, 590.03±511.34 in two-vessel disease, and 953.35±1023.45 in three-vessel disease (p<0.001). There was a positive association between calcium score and Gensini score (r=0.636, p<0.001). In a linear regression model, calcium score was a strong determinant of the severity of coronary artery disease. Calcium scoring had an acceptable value for discriminating coronary disease from normal condition with optimal cutoff point of 350, yielding a sensitivity and specificity of 83% and 70%, respectively.

CONCLUSIONS

Our study confirmed the strong relationship between the coronary artery calcium score and the presence and severity of stenosis in coronary arteries assessed by both the number of diseased coronary vessels and also by the Gnesini score.

A comparison of coronary CTA and stress testing using high-efficiency SPECT MPI for the evaluation of chest pain in the emergency department

BACKGROUND

Recent studies have compared CTA to stress testing and MPI using older Na-I SPECT cameras and traditional rest-stress protocols, but are limited by often using optimized CTA protocols but suboptimal MPI methodology. We compared CTA to stress testing with modern SPECT MPI using high-efficiency CZT cameras and stress-first protocols in an ED population.

METHODS

In a retrospective, non-randomized study, all patients who underwent CTA or stress testing (ETT or Tc-99m sestamibi SPECT MPI) as part of their ED assessment in 2010-2011 driven by ED attending preference and equipment availability were evaluated for their disposition from the ED (admission vs discharge, length of time to disposition), subsequent visits to the ED and diagnostic testing (within 3 months), and radiation exposure. CTA was performed using a 64-slice scanner (GE Lightspeed VCT) and MPI was performed using a CZT SPECT camera (GE Discovery 530c). Data were obtained from prospectively acquired electronic medical records and effective doses were calculated from published conversion factors. A propensity-matched analysis was also used to compare outcomes in the two groups.

RESULTS

A total of 1,458 patients underwent testing in the ED with 192 CTAs and 1,266 stress tests (327 ETTs and 939 MPIs). The CTA patients were a lower-risk cohort based on age, risk factors, and known heart disease. A statistically similar proportion of patients was discharged directly from the ED in the stress testing group (82% vs 73%, P = .27), but their time to disposition was longer (11.0 ± 5 vs 20.5 ± 7 hours, P < .0001). There was no significant difference in cardiac return visits to the ED (5.7% CTA vs 4.3% stress testing, P = .50), but more patients had follow-up studies in the CTA cohort compared to stress testing (14% vs 7%, P = .001). The mean effective dose of 12.6 ± 8.6 mSv for the CTA group was higher (P < .0001) than 5.0 ± 4.1 mSv for the stress testing group (ETT and MPI). A propensity score-matched cohort showed similar results to the entire cohort.

CONCLUSIONS

Stress testing with ETT, high-efficiency SPECT MPI, and stress-only protocols had a significantly lower patient radiation dose and less follow-up diagnostic testing than CTA with similar cardiac return visits. CTA had a shorter time to disposition, but there was a trend toward more revascularization than with stress testing.

What is the optimal cut-off point for low coronary artery calcium score assessed by computed tomography? Multi-Detector Computed Tomography ANIN Registry

AIM

This prospective study was conducted to evaluate the incidence and predictors of coronary artery disease (CAD) in relation to the low coronary artery calcium (CAC) score among patients with intermediate probability of CAD.

MATERIAL AND METHODS

A total of 1132 consecutive patients were included in the analysis (58.7 ±10.9 years, 46.7% males). Coronary computed tomography (CCT) angiography was performed in a multi-detector computed tomography scanner. Coronary artery calcium score was calculated by the Agatston method. Obstructive CAD was defined as the presence of coronary artery stenosis ≥ 50% on CCT angiography.

RESULTS

Coronary artery disease was diagnosed in nearly one-fourth of patients (n = 272, 24%). In the receiver operating characteristics (ROC) curve analysis a CAC score of 10 was used as an optimal cut-off point for discriminating obstructive CAD (sensitivity: 0.79, specificity: 0.75, p < 0.0001) whereas for a CAC score of 100 the sensitivity and specificity were 0.48 and 0.92, respectively. On multivariate analysis after adjustment for age, gender, hypertension, hyperlipidemia, creatinine levels, only in patients with CAC score ≤ 10 age (OR = 1.05, 95% CI: 1.02-1.08, p = 0.0005, OR = 1.05, 95% CI: 1.03-1.08, p < 0.0001) and male gender (OR = 3.45, 95% CI: 1.92-6.22, p < 0.0001), likewise in group with CAC score ≤ 100 age (OR = 1.05, 95% CI: 1.03-1.08, p < 0.0001) and male gender (OR = 3.31, 95% CI: 1.88-5.81, p < 0.0001) were independent predictors of obstructive CAD.

CONCLUSIONS

The cut-off point of 10 for CAC score determined patients with CAD with the best sensitivity and specificity. Therefore, a total CAC score < 10 should be classified as "low". In patients with a low CAC score obstructive high risk plaques prone to rupture are presented and are associated with increasing age and male gender.

Automatic assessment of coronary artery calcium score from contrast-enhanced 256-row coronary computed tomography angiography

The coronary artery calcium score (CS), an independent predictor of cardiovascular events, can be obtained from a stand-alone nonenhanced computed tomography (CT) scan (CSCT) or as an additional nonenhanced procedure before contrast-enhanced coronary CT angiography (CCTA). We evaluated the accuracy of a novel fully automatic tool for computing CS from the CCTA examination. One hundred thirty-six consecutive symptomatic patients (aged 59 ± 11 years, 40% female) without known coronary artery disease who underwent both 256-row CSCT and CCTA were studied. Original scan reconstruction (slice thickness) was maintained (3 mm for CSCT and 0.67 mm for CCTA). CS was computed from CCTA by an automatic tool (COR Analyzer, rcadia Medical Imaging, Haifa, Israel) and compared with CS results obtained by standard assessment of nonenhanced CSCT (HeartBeat CS, Philips, Cleveland, Ohio). We also compared both methods for classification into 5 commonly used CS categories (0, 1 to 10, 11 to 100, 101 to 400, >400 Agatston units). All scans were of diagnostic quality. CS obtained by the COR Analyzer from CCTA classified 111 of 136 (82%) of patients into identical categories as CS by CSCT and 24 of remaining 25 into an adjacent category. Overall, CS values from CCTA showed high correlation with CS values from CSCT (Spearman rank correlation = 0.95, p <0.0001). In conclusion, CS values automatically computed from 256-row CCTA correlated highly with standard CS values obtained from nonenhanced CSCT. CS obtained directly from CCTA may obviate the need for an additional scan and attendant radiation.

Incremental prognostic value of coronary computed tomographic angiography over coronary artery calcium score for risk prediction of major adverse cardiac events in asymptomatic diabetic individuals

BACKGROUND

Coronary artery disease (CAD) diagnosis by coronary computed tomographic angiography (CCTA) is useful for identification of symptomatic diabetic individuals at heightened risk for death. Whether CCTA-detected CAD enables improved risk assessment of asymptomatic diabetic individuals beyond clinical risk factors and coronary artery calcium scoring (CACS) remains unexplored.

METHODS

From a prospective 12-center international registry of 27,125 individuals undergoing CCTA, we identified 400 asymptomatic diabetic individuals without known CAD. Coronary stenosis by CCTA was graded as 0%, 1-49%, 50-69%, and ≥70%. CAD was judged on a per-patient, per-vessel and per-segment basis as maximal stenosis severity, number of vessels with ≥50% stenosis, and coronary segments weighted for stenosis severity (segment stenosis score), respectively. We assessed major adverse cardiovascular events (MACE) - inclusive of mortality, nonfatal myocardial infarction (MI), and late target vessel revascularization ≥90 days (REV) - and evaluated the incremental utility of CCTA for risk prediction, discrimination and reclassification.

RESULTS

Mean age was 60.4 ± 9.9 years; 65.0% were male. At a mean follow-up 2.4 ± 1.1 years, 33 MACE occurred (13 deaths, 8 MI, 12 REV) [8.25%; annualized rate 3.4%]. By univariate analysis, per-patient maximal stenosis [hazards ratio (HR) 2.24 per stenosis grade, 95% confidence interval (CI) 1.61-3.10, p < 0.001], increasing numbers of obstructive vessels (HR 2.30 per vessel, 95% CI 1.75-3.03, p < 0.001) and segment stenosis score (HR 1.14 per segment, 95% CI 1.09-1.19, p < 0.001) were associated with increased MACE. After adjustment for CAD risk factors and CACS, maximal stenosis (HR 1.80 per grade, 95% CI 1.18-2.75, p = 0.006), number of obstructive vessels (HR 1.85 per vessel, 95% CI 1.29-2.65, p < 0.001) and segment stenosis score (HR 1.11 per segment, 95% CI 1.05-1.18, p < 0.001) were associated with increased risk of MACE. Beyond age, gender and CACS (C-index 0.64), CCTA improved discrimination by maximal stenosis, number of obstructive vessels and segment stenosis score (C-index 0.77, 0.77 and 0.78, respectively). Similarly, CCTA findings improved risk reclassification by per-patient maximal stenosis [integrated discrimination improvement (IDI) index 0.03, p = 0.03] and number of obstructive vessels (IDI index 0.06, p = 0.002), and by trend for segment stenosis score (IDI 0.03, p = 0.06).

CONCLUSION

For asymptomatic diabetic individuals, CCTA measures of CAD severity confer incremental risk prediction, discrimination and reclassification on a per-patient, per-vessel and per-segment basis.

Diagnostic and prognostic value of absence of coronary artery calcification in patients with stable chest symptoms

The aim of this study was to determine the prognostic value of a coronary artery calcium score (CACS) of 0 in patients with stable chest symptoms and to compare it as a first-line test with bicycle exercise testing (X-ECG). Altogether, 315 consecutive patients over 44 years of age, with stable chest symptoms and no previous diagnosis of coronary artery disease (CAD) visited the outpatient clinic of our community hospital and underwent both CACS and X-ECG. The mean age was 60.54 years (SD 9.7; range 45-88 years). Of these patients, 141 had no detectable coronary calcium (44.8%) We excluded patients who did not sign informed consent (n = 4). Three patients were lost to follow-up. The follow-up group therefore consisted of 134 patients. The mean follow-up period was 44.6 months (25th-75th percentile: 35.5-54.3 months), during which no major adverse cardiac events (MACE) occurred. The negative predictive value (NPV) was 100%. X-ECG was negative in only 89 patients, equivocal in 39 patients and false-positive in 6 patients requiring additional stress myocardial imaging in 45 patients. NPV as a first-line test was therefore 66.4%.

IN CONCLUSION

patients over 44 years with stable chest symptoms and no detectable coronary calcium have an excellent prognosis. CACS performs better compared with X-ECG as an initial test in patients with stable chest symptoms.

Comparison of different cardiac risk scores for coronary artery disease in symptomatic women: do female-specific risk factors matter?

BACKGROUND

Cardiovascular diseases remain the leading cause of death in women and there is a need for more accurate risk assessment scores. The aims of our study were to compare the accuracy of several widely used cardiac risk assessment scores in predicting the likelihood of obstructive coronary artery disease (CAD) on CT coronary angiography (CTCA) in symptomatic women and to explore which female-specific risk factors were independent predictors of obstructive CAD on CTCA and whether adding these risk factors to pre-test probability scores would improve their predictive value.

METHODS AND RESULTS

Data were obtained from a cohort of 228 consecutively included symptomatic women undergoing evaluation for CAD and referred for CTCA. Obstructive CAD was defined as ≥50% luminal stenosis on CTCA. Pre-test probability for CAD was calculated according to the Diamond and Forrester score, New score, Duke clinical score, and an updated Diamond and Forrester score. Female-specific factors were obtained by a written questionnaire. Pre-test probability scores were compared with ROC analysis and showed that only the New score and the updated Diamond and Forrester score were significant predictive scores for obstructive CAD on CTCA (area under the curve, AUC, 0.67, p < 0.01; AUC 0.61, p = 0.04, respectively). Multivariable logistic regression analysis identified that gestational diabetes mellitus (GDM) and oestrogen status were independent predictors of obstructive CAD when adjusted for the pre-test probability scores. The updated Diamond and Forrester score was used for net reclassification improvement (NRI) analysis, since the New score already accounts for oestrogen status. Adding GDM and oestrogen status to the updated Diamond and Forrester score resulted in a significant NRI (p = 0.04).

CONCLUSIONS

There is a large variability in prediction of obstructive CAD using different pre-test probability risk scores in symptomatic women. Logistic regression analysis revealed that oestrogen status and GDM were independently associated with the occurrence of obstructive stenosis on CTCA. The predictive ability of cardiac pre-test probability scores improved significantly with the addition of oestrogen status and GDM.

Asymptomatic subjects with zero coronary calcium score: coronary CT angiographic features of plaques in event-prone patients

The aims of this study were: (a) to assess clinical predictors and coronary computed tomography angiography (CCTA) characteristics of noncalcified coronary plaques (NCP) in subjects who had cardiac events despite a zero coronary artery calcium score (CACS), and (b) to describe computed tomography (CT) plaque characteristics in subjects with cardiac events. A total of 7,961 subjects with zero CACS were evaluated; 6,531 subjects underwent CCTA as part of a health check-up. Those who had zero CACS were included in our mid-term follow-up study. Cardiac events included cardiac death, acute coronary syndrome or revascularization with stable angina. More than one NCP was identified in 441 subjects with zero CACS, including 48 subjects with obstructive coronary artery disease (CAD) caused by NCPs. Age, male gender, hypertension, diabetes and low density lipoprotein were independent predictors of obstructive CAD. Among subjects with obstructive CAD, young adults were classified into low (79.2 %) or moderate (72.9 %) risk groups by the National Centers for Environmental Prediction III guidelines. Approximately 0.2 % of subjects had cardiac events during our follow-up period. All patients with cardiac events had NCPs with significantly lower mean CT numbers, higher remodeling indexes and worse degree of stenosis. In asymptomatic subjects with zero CACS, NCP was associated with cardiac events. CCTA might be useful for risk stratification among select populations with CAD and zero CACS who have certain plaque characteristics associated with cardiac events.