Clinical perspective of coronary computed tomographic angiography in diagnosis of coronary artery disease

Risk factors and utility of maximum carotid intima-media thickness as a surrogate marker for coronary artery stenosis

Background

This study investigated the factors associated with coronary artery stenosis in outpatients. Furthermore, the usefulness of maximum carotid intima–media thickness (maximum-IMT) as a surrogate marker of coronary artery stenosis was evaluated.

Methods

We conducted a single-center retrospective study. A total of 601 outpatients (338 males; 263 females; mean age, 69.8±10.0 years) who underwent coronary computed tomography angiography between April 2006 and March 2012 were analyzed. The associations between coronary artery stenosis (≥75%) as determined by coronary computed tomography angiography and clinical and laboratory parameters were evaluated by multivariate logistic regression. Validation of maximum-IMT as measured by ultrasonography as a surrogate marker of coronary artery stenosis was analyzed by receiver operating characteristic (ROC) curve analysis.

Results

The estimated glomerular filtration rate (eGFR: mL/min/1.73 m²) (odds ratio [OR] 0.985, p<0.01), diabetes mellitus (OR 1.98, p<0.05), and maximum-IMT (mm) (OR 1.76, p<0.01) were significantly associated with coronary artery stenosis (≥75%). In analysis of each group categorized by identified factors, such as renal impairment (eGFR <60 mL/min/1.73 m²) and diabetes mellitus, the ROC curve of maximum-IMT was significant in the group of patients with diabetes mellitus without renal impairment (p<0.01) (cutoff value of maximum-IMT, 2.0 mm; sensitivity, 0.74; and specificity, 0.54) but not in other groups.

Conclusion

Renal impairment, diabetes mellitus, and increased maximum-IMT may be significant risk factors of coronary artery stenosis. Maximum-IMT as measured by ultrasonography may be a useful surrogate marker for coronary artery stenosis in patients with diabetes mellitus without renal impairment but not in other patients.

Computed Tomography Diagnosis of Nonspecific Acute Chest Pain in the Emergency Department: From Typical Acute Coronary Syndrome to Various Unusual Mimics

It is a challenging task for emergency department physicians to establish a precise and rapid diagnosis based only on clinical and laboratory findings in patients who present with nonspecific acute chest pain. In this circumstance, CT angiography can provide important clues to the diagnosis. To provide a rapid diagnosis of acute coronary syndrome (ACS) and its various mimics, the physician should enumerate each possible cause of acute chest pain on the basis of an objective assessment of pretest probability. On the basis of clinical suspicion, the appropriate CT protocol should then be performed. Moreover, radiologists should be familiar with typical CT findings of ACS and its various mimics to assist the emergency department physician in diagnosing patients with nonspecific acute chest pain. This review article presents an overview on choosing an appropriate CT protocol in patients with nonspecific acute chest pain and provides specific CT findings of ACS and various mimics of ACS.

Differential Prognostic Value of Coronary Computed Tomography Angiography in Relation to Exercise Electrocardiography in Asymptomatic Subjects

BACKGROUND

To explore the prognostic performance of coronary computed tomography angiography (CCTA) and exercise electrocardiography (XECG) in asymptomatic subjects.

METHODS

We retrospectively enrolled 812 (59 ± 9 years, 60.8% male) asymptomatic subjects who underwent CCTA and XECG concurrently from 2003 through 2009. Subjects were followed-up for major adverse cardiac events (MACE) including cardiac death, nonfatal myocardial infarction, unstable angina, and revascularization after 90 days from index CCTA.

RESULTS

The prevalence of occult coronary artery disease (CAD) detected by CCTA was 17.5% and 120 subjects (14.8%) had positive XECG. During a mean follow-up of 37 ± 16 months, nine subjects experienced MACE. In multivariable Cox-regression analysis, only the presence of CAD by CCTA independently predicted future MACE (p = 0.002). Moreover, CAD by CCTA improved the predictive value when added to a clinical risk factor model using the likelihood ratio test (p < 0.001). Notably, the prognostic value of CCTA persisted in the moderate-to-high-risk group as classified by the Duke treadmill score (p = 0.040), but not in the low-risk group (p = 0.991).

CONCLUSION

CCTA provides incremental prognostic benefit over and above XECG in an asymptomatic population, especially for those in a moderate-to-high-risk group as classified by the Duke treadmill score. Risk stratification using XECG may prove valuable for identifying asymptomatic subjects who can benefit from CCTA.

Insight into the Spectrum of Coronary Atherosclerosis in Asymptomatic Urban Han Chinese Population by Coronary Computed Tomography Angiography

OBJECTIVES

Highlighted the spectrum of coronary atherosclerosis in asymptomatic population by Computed Tomography Angiography (CTA) and developed a surrogation of expensive CTA to early detect coronary atherosclerosis.

METHODS

Three hundred and seven self-referred urban Han Chinese asymptomatic individuals underwent coronary CTA were consecutively enrolled. Total plaque score (TPS), Segment stenosis score (SSS) and Coronary Artery Disease severity (CADS) were used to measure and illustrate the spectrum of atherosclerosis burden by mapping their incidence and proportion onto coronary artery tree. Logistic regression model was further used to explore the association between lipid biomarkers and TPS (SSS) for developing a surrogation of CTA to early detect coronary atherosclerosis.

RESULTS

We found that the incidence of TPS, SSS and CADS were up to 71.34%, 68.08%, and 71.34%; and high-risk individuals reached up to 11.07%, 15.31% and 16.29% respectively. All TPS, SSS and CADS were much higher in male than female, and have trend of increasing with age. The most lesion segment emerged on proximal LAD, followed by proximal RCA, mid LAD, proximal LCX, and mid RCA with mixed plaque as dominant. HDL-C was a predictor to both TPS [OR: 0.12 (0.02-0.82)] and SSS [OR: 0.15 (0.03-0.76)], and could identify the serious atherosclerosis subjects of TPS or SSS score >5 (AUC 0.73 and 0.70).

CONCLUSIONS

The atherosclerosis plaque burden was about one in ten as high-risk individuals in this specific urban Han Chinese population. As potential surrogation of CTA, HDL-C was recognized as a significant predictor to atherosclerosis burden and revealed a good performance for identifying high-risk individuals.

Impaired aortic elasticity and diastolic functions are associated with findings of coronary computed tomographic angiography

BACKGROUND

Coronary artery disease (CAD) is the leading cause of mortality and morbidity worldwide. Aortic elasticity and diastolic functions are helpful parameters in assessment of CAD. In this study we aimed to learn whether diastolic function and aortic elastic properties measured by echocardiography are associated with coronary calcium score (CACS), epicardial fat volume (EFV), and plaque area measured by coronary tomographic angiography.

MATERIAL AND METHODS

We enrolled 106 consecutive patients suspected of CAD undergoing coronary CTA and transthoracic echocardiography in this prospective study. Total CACS, plaque area, and EFV were calculated via CTA. Aortic stiffness index (ASI) and aortic distensibility (AD) were measured via echocardiography.

RESULTS

The patients with diastolic dysfunctions of any degree had significantly higher ASI, higher CACS, higher plaque area, and EFV. We found that as the ASI increases, the CACS and total coronary plaque area both increase, showing that there is a strong positive correlation between ASI, CACS, and total coronary plaque area. There was a significant correlation between ASI and EFV, but with a lower statistical value.

CONCLUSIONS

Aortic elasticity was correlated with CACS and plaque area. Diastolic dysfunction was observed more commonly among patients with higher CACS and EFV. Epicardial fat volume was not as strong as CACS in reflecting aortic elasticity.

Comparison of the Framingham risk score, UK Prospective Diabetes Study (UKPDS) Risk Engine, Japanese Atherosclerosis Longitudinal Study-Existing Cohorts Combine (JALS-ECC) and maximum carotid intima-media thickness for predicting coronary artery stenosis in patients with asymptomatic type 2 diabetes

AIMS

To compare the efficacy of Framingham Risk Score (FRS), UK Prospective Diabetes Study (UKPDS) risk engine, a risk score based on the Japanese Atherosclerosis Longitudinal Study-Existing Cohorts Combine (JALS-ECC), the maximum intima-media thickness (max-IMT) determined on coronary computed tomography angiography (CCTA) and their combination in asymptomatic patients with type 2 diabetes.

METHODS

A total of 116 Japanese patients with type 2 diabetes underwent CCTA. The risk of coronary heart disease was calculated according to the FRS, UKPDS and JALS-ECC. We evaluated the reclassification of coronary artery stenosis (CAS) based on the risk score categories after adding each IMT related variable.

RESULTS

Sixty-eight patients had CAS. The areas under the curves (AUCs) in the receiver operating characteristic curve analyses of FRS, UKPDS and JALS-ECC were 0.763 (95% confidence interval [CI]: 0.674-0.853), 0.785 (95% CI: 0.703-0.868) and 0.767 (95% CI: 0.681-0.853), respectively. The AUCs for FRS, UKPDS and JALS-ECC combined with the max-IMT were 0.788 (95% CI: 0.705-0.872), 0.800 (95% CI: 0.720-0.879) and 0.786 (95% CI: 0.703-0.869), respectively. Combining the max-IMT with the risk scores improved the identification of subjects with stenotic lesions, in particular, those in the first, second and third tertiles of the FRS, first and second tertiles of the UKPDS and first and second tertiles of the JALS-ECC (P=0.054, P=0.056, P=0.015, P=0.082, P=0.060, P=0.007, and P=0.080, respectively). The net reclassification improvement increased following the addition of a max-IMT of ≥ 1.9 mm (32.4% in FRS, 19.9% in UKPDS and 51.7% in JALS-ECC).

CONCLUSIONS

These data suggest that combining a risk score with the max-IMT improves the prediction of CAS in comparison with the risk score alone.

Impact of coronary CT angiography on surgical decision-making for coronary artery bypass graft surgery

RATIONALE AND OBJECTIVES

To determine the impact of coronary computed tomography angiography (CCTA) on treatment decisions made by cardiac surgeons and to explore barriers to implementation of CCTA as first-line imaging workup before coronary artery bypass.

MATERIALS AND METHODS

Tertiary academic medical center retrospective cohort study. Questionnaires administered to three cardiac surgeons regarding diagnosis and treatment decisions with level of confidence in decision making for 30 chest pain patients, after reviewing deidentified catheter coronary angiogram (CCA) and CCTA images on the same patients, several weeks apart.

RESULTS

All surgeons tended to report more severe disease with CCTA than CCA (P < .05). Treatment decisions differed in 12 (40%), 14 (47%), and 18 (60%) patients within each individual surgeon based on CCTA images compared to CCA images (P = .11, .01, and .02, respectively). Confidence levels were significantly higher with CCA for the diagnosis and treatment of coronary artery disease for all three surgeons (P < .05). There was a tendency toward more invasive treatment choices (angioplasty, stent insertion, or coronary artery bypass graft) when making treatment decisions based upon CCTA images.

CONCLUSIONS

Severity of disease may be overestimated by cardiac surgeons when using CCTA as a decision-making test, tending toward more invasive treatment choices compared to CCA. Additionally, cardiac surgeons may be more confident with their diagnosis and treatment based on CCA. These may be important limitations in the application of CCTA in clinical practice and may reflect the maturation of CCTA use in practice, diffusion of the technology and/or a reflection of the technology itself.

Characterization of culprit lesions in acute coronary syndromes compared with stable angina pectoris by dual-source computed tomography

To identify the characterization of culprit lesions in acute coronary syndrome (ACS) compared with stable angina pectoris (SAP) by dual-source computed tomography (DSCT). 65 patients with ACS and 75 controls with SAP and a similar atherosclerotic risk profile were studied. Computed tomography (CT) coronary angiography was performed using a DSCT scanner before invasive catheterization. Using DSCT and quantitative coronary angiography (QCA), lesion characteristics [luminal cross-section area (L-CSA), vascular cross-section area (V-CSA), plaque area and degree of stenosis) were detected. Plaque types, mean and minimum CT density (Hounsfield Unit; HU), remodeling index, and presence of "spotty" calcifications were analyzed using DSCT. A good correlation was observed between DSCT and QCA for all lesion characteristics (P < 0.05). Culprit lesions in ACS had much larger V-CSA (20.5 ± 6.0 vs. 14.8 ± 4.8 mm(2)), plaque area (15.3 ± 5.0 vs. 11.1 ± 3.3 mm(2)) and remodeling index (1.3 ± 0.2 vs. 1.0 ± 0.4) than stable lesions in SAP (P < 0.05). The prevalence of non-calcified/calcified/mixed plaque was 30/0/35 in ACS versus 25/15/35 stable lesions in SAP (P < 0.01). The proportion of "spotty" calcified plaques was 21.5 % in culprit lesions (14 of 65) versus 1.3 % in SAP (1 of 75). The mean/minimum HU of culprit lesions was 88.6 ± 43.2/154.2 ± 98.7 in ACS versus 45.9 ± 34.7/98.2 ± 76.8 in SAP (both P < 0.01). DSCT is a feasible means of detecting coronary stenosis with good accuracy compared with QCA. Culprit lesions in ACS display a greater proportion of non-calcified material with lower CT attenuation, "spotty" calcifications and higher remodeling index compared with SAP lesions.