Multislice computed tomography for determination of coronary artery disease in a symptomatic patient population

Correlation of coronary artery calcium score and carotid artery intima-media thickness with severity of coronary artery disease

Introduction: Coronary artery calcium score (CACS) and carotid artery intima-media thickness (CIMT) are the markers of atherosclerosis. An association between CACS and CIMT with presence of atherosclerotic coronary artery disease (CAD) is well established. However relationship between severity of CAD with CACS and CIMT is less clear. This study aimed to investigate the correlation between severity of CAD assessed by SYNTAX and Gensini scores with CACS and CIMT.

Methods: This prospective study was conducted on 351 patients with CAD between June 2015 to December 2016. CACS was obtained using AGATSTON algorithm with 128 slice multidetector computer tomography (MDCT) before conventional coronary angiography (CCA). CIMT was measured by using Philips IE33 Echo machine. The severity of CAD was assessed by SYNTAX score (SS) and Gensini score on CCA. Correlation between severity of CAD with CACS and CIMT was analysed.

Results: Mean CACS was 241.5±463.7, and this was positively correlated with over all SS (r=0.417, P <0.0001) and Gensini score (r=0.405, P<0.0001). Mean CIMT was 0.80±0.18 mm and this was also significantly correlated with SS (r=0.450, P<0.0001) and Gensini score (r=0.459,<0.0001). Multivariate analysis showed that CACS was independently associated with diabetes mellitus (β:0.11, P=0.021), SS (β:0.251, P =0.010) and mean CIMT (β:0.128, P =0.028). Receiver-operating characteristic (ROC) curve analysis revealed a cut off CACS of >493 for SS≥33 (high-SS tertile).

Conclusion: Our study confirmed a significant correlation between CACS and CIMT with the severity of CAD assessed by SS and Gensini scores. CACS and CIMT may be considered as important noninvasive diagnostic modalities in the assessment of the severity of CAD.

Diagnosing peripheral lung lesions using endobronchial ultrasonography with guide sheath: A prospective registry study to assess the effect of virtual bronchoscopic navigation using a computed tomography workstation

Bronchoscopy has a lower diagnostic yield for peripheral lung lesions (PLL). Endobronchial ultrasound guide sheath transbronchial lung biopsy (EBUS GS TBLB) has been used to overcome such limitation. Recent studies revealed that combined methods (e.g., EBUS GS TBLB plus electromagnetic navigation [EMN] or virtual bronchoscopic navigation [VBN]) further improve the diagnostic yield. However, those systems are associated with a high cost burden. Accordingly, we attempted to use VBN by computed tomography (CT) workstation (Aquarius iNtuition, TeraRecon) not dedicated only for VBN as an adjunctive tool for EBUS GS TBLB. We performed a prospective registry study to investigate whether VBN by CT workstation could improve the diagnostic yield of PLL.Between February 2017 and February 2018, 128 patients with PLL were divided into 2 groups (VBN and non-VBN [NVBN]). In NVBN group (n = 64), EBUS GS TBLB was performed using a hand-drawn bronchial map based on CT images. VBN group (n = 64) underwent EBUS GS TBLB using VBN images.VBN using CT workstation did not improve the diagnostic yield of EBUS GS TBLB for PLL (VBN vs NVBN, 72% vs 80%, P = .284). VBN slightly reduced procedure time (minute [mean ± SD], 25.31 ± 10.33 vs 25.81 ± 9.22), navigation time (time to find the lesion) (9.10 ± 7.88 vs 9.50 ± 7.14), and fluoroscopy time (2.23 ± 2.39 vs 2.86 ± 4.61), while these differences were not statistically significant.The diagnostic yield of EBUS GS TBLB was not improved with VBN (compared with using a hand-drawn bronchial map). Although VBN slightly shortened the procedure-related times, which were not significantly different.

Diagnostic utility of endobronchial ultrasound with a guide sheath under the computed tomography workstation (ziostation) for small peripheral pulmonary lesions

BACKGROUND AND AIMS

The application of radial probe endobronchial ultrasound (R-EBUS) and virtual bronchoscopic navigation has improved the diagnostic outcome of bronchoscopy for peripheral pulmonary lesions (PPLs). Nonetheless, while existing navigation systems are very useful for selecting the bronchus containing the target lesion, the associated introductory costs are high. Therefore, we focused on virtual bronchoscopy (VB) using the workstation, ziostation that was already available in many countries as an adjunct modality.

METHODS

Consecutive patients who underwent bronchoscopy with R-EBUS for PPLs (major diameter ≤30 mm) were enrolled. From late June 2013 to November 2013, 121 patients were examined with ziostation, and from September 2012 to early June 2013, 113 patients were examined without ziostation. We compared the diagnostic yield, EBUS detection rate and procedure time between two groups to evaluate the utility of the VB.

RESULTS

The ziostation group had significantly higher diagnostic yield than the non-ziostation group (77.7% vs 64.6%, P = 0.030). Following the multivariate analysis, use of ziostation was a significant factor affecting the diagnostic yield. Meanwhile, EBUS detection rate was significantly higher in the ziostation group (94.2% vs 75.2%, P < 0.001). And, procedure time was significantly shorter in the ziostation group (mean ± standard deviation: 24.0 ± 7.4 min vs 26.9 ± 7.9 min, P = 0.005).

CONCLUSION

VB offered by the workstation was a valuable tool that facilitated more accurate and rapid bronchoscopy procedure for diagnosis of PPLs.

Value of coronary artery calcium score to predict severity or complexity of coronary artery disease

BACKGROUND

Prediction of severity or complexity of coronary artery disease (CAD) is valuable owing to increased risk for cardiovascular events. Although the association between total coronary artery calcium (CAC) score and severity of CAD, Gensini score was not used, it has been previously demonstrated. There is no information about the association between total CAC score and complexity of CAD.

OBJECTIVES

To investigate the association between severity or complexity of coronary artery disease (CAD) assessed by Gensini score and SYNTAX score (SS), respectively, and coronary artery calcium (CAC) score, which is a noninvasive method for CAD evaluation in symptomatic patients with accompanying significant CAD.

METHODS

Two-hundred-fourteen patients were enrolled. Total CAC score was obtained before angiography. Severity and complexity of CAD was assessed by Gensini score and SS, respectively. Associations between clinical and angiographic parameters and total CAC score were analyzed.

RESULTS

Median total CAC score was 192 (23.0-729.8), and this was positively correlated with both Gensini score (r: 0.299, p<0.001) and SS (r: 0.577, p<0.001). At multivariate analysis, it was independently associated with age (ß: 0.154, p: 0.027), male gender (ß: 0.126, p: 0.035) and SS (ß: 0.481, p<0.001). Receiver-operating characteristic (ROC) curve analysis revealed a cut-off value>809 for SS>32 (high SS tertile).

CONCLUSION

In symptomatic patients with accompanying significant CAD, total CAC score was independently associated with SS and patients with SS>32 may be detected through high Agatston score.

Utility of coronary artery calcium scoring in the evaluation of patients with chest pain

Although coronary artery calcium (CAC) scoring has an established role in risk-stratifying asymptomatic patients at intermediate risk of coronary heart disease (CHD), its utility in the evaluation of patients with chest pain is uncertain. We conducted a literature review of articles investigating the utility of: (1) CAC scoring in elective patients with indeterminate chest pain symptoms, (2) CAC as a "gatekeeper" in the triage of patients presenting to the emergency department (ED) with chest pain, and (3) the cost-effectiveness of the use of CAC scoring in the ED. We also evaluated the predictive accuracy of the absence of CAC in a pooled analysis of applicable studies. Only studies evaluating patients classified as low or intermediate risk were included. Low to intermediate risk was established by Framingham risk scores, Thrombolysis in Myocardial Infarction scores, Diamond-Forrester classification, or by the absence of typical angina symptoms, ischemic electrocardiogram, positive cardiac biomarkers, or a prior history of CHD. In our pooled analysis, the presence of any CAC resulted in a high sensitivity (range 70%-100%) for predicting the presence of obstructive coronary disease among symptomatic patients subsequently referred for coronary angiography. More importantly, a CAC score of 0 in low- and intermediate-risk ED populations with chest pain had a high negative predictive value (99.4%) for CHD events over an average follow-up of 21 months. CAC scoring also seems cost-effective in this population. Although further research is needed, carefully selected ED patients with a normal electrocardiogram, normal cardiac biomarkers, and CAC = 0 may be considered for early discharge without further testing.

Economic analysis of the use of coronary calcium scoring as an alternative to stress ECG in the non-invasive diagnosis of coronary artery disease

OBJECTIVE

To conduct an economic analysis (EA) of coronary calcium scoring (CCS) using a 0 score, as alternative to stress electrocardiography (sECG) in diagnosing coronary artery disease (CAD).

METHOD

A decision tree was constructed to compare four strategies for investigation of suspected CAD previously assessed in the formulation of clinical guidelines for the United Kingdom (UK) to two new strategies incorporating CCS. Sensitivity (96%; 95% CI 95.4-96.4%) and specificity (40%; 95% CI 38.7-41.4%) values for CCS were derived from a meta-analysis of 10,760 patients. Other input variables were obtained from a previous EA and average prices for hospital procedures in the UK. A threshold of £30,000/Quality-adjusted Life Year (QALY) was considered cost-effective.

RESULTS

Using net monetary benefit calculations, CCS-based strategies were found to be cost-effective compared to sECG equivalents at all assessed prevalence of CAD. Using CCS prior to myocardial perfusion scintigraphy (MPS) and catheter angiography (CA) was found to be cost-effective at pre-test probabilities (PTP) below 30%.

CONCLUSIONS

Adoption of CCS as an alternative to sECG in investigating suspected stable angina in low PTP population (<30%) would be cost-effective. In patients with PTP of CAD >30%, proceeding to MPS or CA would be more cost-effective than performing either CCS or sECG.

KEY POINTS

Coronary calcium scoring (CCS) is useful for assessing coronary artery atherosclerosis It can be performed with multi-detector CT, which is now widely available It plays a role in excluding disease in suspected stable angina Our study assesses its role in this setting as alternative to stress-ECG Adoption of CCS as an alternative to sECG could prove cost-effective.

Computer assistance for solving imaging problems

Medical imaging has moved into an era of digital files and processing of images to yield three-dimensional models and reconstructions. This development has opened up opportunities to apply computer techniques in traditional imaging tasks. Two of the most common imaging tasks are those to correct the two-dimensional projection problems of foreshortening of lesions and of vessel overlap. This article explores the use of computers to assist in these tasks, to create databases for guiding decision making, to provide graphics to assist the physician, and to simulate cardiovascular procedures.

Calcification in atherosclerosis

Coronary calcification has long been known to occur as a part of the atherosclerotic process, although whether it is a marker of plaque stability or instability is still a topic of considerable debate. Coronary calcification is an active process resembling bone formation within the vessel wall and, with the advances in CT technology of the past decade, can be easily quantified and expressed as a coronary artery calcium (CAC) score. The extent of calcium is thought to reflect the total coronary atherosclerotic burden, which has generated interest in using CAC as a marker of risk of cardiovascular events. The current consensus is that large amounts of CAC identify a highly vulnerable patient rather than a vulnerable plaque or vulnerable vessel. Indeed, CAC has incremental prognostic value beyond traditional risk factors in various subsets of the population. Furthermore, whereas the presence of CAC is associated with increased risk, a zero CAC score predicts excellent short-term to mid-term prognosis, even in high-risk patients. The advent of CT angiography has perhaps clouded the importance of CAC as a long-term marker of risk, as opposed to the presence of luminal stenoses that are associated with a more immediate risk of events.

Cardiac CT in asymptomatic patients at risk

Atherosclerosis is a systemic process that can develop as early as the second or third decade of life. A significant percentage of patients who experience acute coronary syndromes often have non-obstructive coronary artery disease and thus cannot be diagnosed by their symptoms or conventional functional stress testing. It has been proposed that early detection of atherosclerosis would generate novel opportunities for primary prevention through changes in lifestyle or even through drug therapy, especially in patients at high cardiovascular risk. Calcium scoring is a simple, reproducible, and widely available test that has been extensively validated over the past two decades. In this article, the utility of calcium scoring and the potential application of CT coronary angiography in asymptomatic patients at risk are reviewed.

Diagnostic and prognostic value of absence of coronary artery calcification

OBJECTIVES

In this study, we systematically assessed the diagnostic and prognostic value of absence of coronary artery calcification (CAC) in asymptomatic and symptomatic individuals.

BACKGROUND

Presence of CAC is a well-established marker of coronary plaque burden and is associated with a higher risk of adverse cardiovascular outcomes. Absence of CAC has been suggested to be associated with a very low risk of significant coronary artery disease, as well as minimal risk of future events.

METHODS

We searched online databases (e.g., PubMed and MEDLINE) for original research articles published in English between January 1990 and March 2008 examining the diagnostic and prognostic utility of CAC.

RESULTS

A systematic review of published articles revealed 49 studies that fulfilled our criteria for inclusion. These included 13 studies assessing the relationship of CAC with adverse cardiovascular outcomes in 64,873 asymptomatic patients. In this cohort, 146 of 25,903 patients without CAC (0.56%) had a cardiovascular event during a mean follow-up period of 51 months. In the 7 studies assessing the prognostic value of CAC in a symptomatic population, 1.80% of patients without CAC had a cardiovascular event. Overall, 18 studies demonstrated that the presence of any CAC had a pooled sensitivity and negative predictive value of 98% and 93%, respectively, for detection of significant coronary artery disease on invasive coronary angiography. In 4,870 individuals undergoing myocardial perfusion and CAC testing, in the absence of CAC, only 6% demonstrated any sign of ischemia. Finally, 3 studies demonstrated that absence of CAC had a negative predictive value of 99% for ruling out acute coronary syndrome.

CONCLUSIONS

On the basis of our review of more than 85,000 patients, we conclude that the absence of CAC is associated with a very low risk of future cardiovascular events, with modest incremental value of other diagnostic tests in this very low-risk group.

Influence of symptomatic status on the prevalence of obstructive coronary artery disease in patients with zero calcium score

BACKGROUND

CAC has been used to predict obstructive CAD on invasive coronary angiography. However, it is unknown how the prevalence of obstructive CAD in patients with zero CAC is influenced by the presence or absence of chest pain.

METHODS

210 consecutive patients referred for CAC and CorCTA were included in this analysis. Chest pain was defined based on the Diamond-Forrester classification.

RESULTS

134 patients (64%) were symptomatic and 76 (36%) were asymptomatic. Seventy patients had negative (33%); 140 had positive CAC (67%). In the symptomatic group with zero CAC, 8.2% (4/49) had an obstructive, non-calcified plaque; of these, 3 were <45 years. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of CAC in the symptomatic population for detection of obstructive CAD were 0.86 (0.66-0.95), 0.42 (0.33-0.52), 0.28 (0.19-0.39) and 0.92 (0.8-0.97), respectively (p=0.007). No asymptomatic subject with zero CAC had obstructive CAD. Sensitivity, specificity, PPV and NPV of CAC in the asymptomatic population for detection of obstructive CAD were 1.00 (0.66-1.00), 0.32 (0.21-0.45), 0.18 (0.10-0.31) and 1.00 (0.80-1.00), respectively (p=0.05). Optimal cut-points to predict obstructive CAD and AUC were significantly different in symptomatic versus asymptomatic subjects (91 and 0.78 vs. 296 and 0.89, respectively) (p=0.005). CAC performed much better in symptomatic patients >45 years compared to younger patients to exclude obstructive CAD (AUC: 0.83 vs. 0.5, p<0.001; NPV=0.98).

CONCLUSIONS

CAC is better in asymptomatic compared to symptomatic subjects, especially in patients <age 45, to exclude obstructive CAD. Symptoms and age should be considered when interpreting CAC.

Coronary artery calcium screening: current status and recommendations from the European Society of Cardiac Radiology and North American Society for Cardiovascular Imaging

Current guidelines and literature on screening for coronary artery calcium for cardiac risk assessment are reviewed for both general and special populations. It is shown that for both general and special populations a zero score excludes most clinically relevant coronary artery disease. The importance of standardization of coronary artery calcium measurements by multi-detector CT is discussed.