Mortality incidence and the severity of coronary atherosclerosis assessed by computed tomography angiography

Association of pericardial fat accumulation rather than abdominal obesity with coronary atherosclerotic plaque formation in patients with suspected coronary artery disease

OBJECTIVES

The purpose of this study was to examine the association of pericardial fat with the presence of coronary plaques.

BACKGROUND

Waist circumference, reflecting abdominal obesity, is a risk factor of metabolic syndrome and coronary artery disease (CAD). Adipose tissue secretes many factors implicated in atherogenesis, however, the role of pericardial fat (ectopic visceral fat around coronary arteries) in the pathogenesis of CAD is not clear.

METHODS

We measured total pericardial fat volume (PFV) and determined presence and characteristics of coronary plaques using 64-slice computed tomography in 171 consecutive patients suspected of CAD (101 men; mean age, 66+/-11 years, +/-SD).

RESULTS

PFV correlated with age (p<0.05), body mass index (p<0.05), waist circumference (p<0.01), and high-density lipoprotein cholesterol (p<0.01) by multivariate regression analysis. PFV was significantly larger in patients with coronary plaques, even nonstenotic or noncalcified ones, than those without plaques (any plaques, n=123; 201+/-71cm(3), nonstenotic plaques, n=51; 192+/-63, noncalcified plaques, n=32; 196+/-56 vs. no plaque, n=48; 144+/-45, p<0.001, respectively). Multivariate backward logistic regression analysis demonstrated that PFV, but not waist circumference, significantly associated with the presence of any coronary plaques (odds ratio [OR]; 2.876, 95% confidence interval [95% CI]; 1.614-5.125, p<0.001), nonstenotic plaques confirmed by coronary angiography (OR; 3.423, 95% CI; 1.764-6.642, p<0.001), and noncalcified plaques (OR; 3.316, 95% CI; 1.435-7.661, p<0.01).

CONCLUSIONS

PFV correlated significantly with the presence of nonstenotic and noncalcified coronary plaques assessed by multislice computed tomography. Pericardial fat is more highly associated with early development of CAD than simple anthropometric measures of abdominal obesity.

Impact of coronary computed tomographic angiography findings on the medical treatment and control of coronary artery disease and its risk factors

Although coronary computed tomographic angiography (CCTA) has high diagnostic accuracy and increasing evidence of prognostic value for coronary artery disease (CAD), its downstream clinical impact is not established. In this study, the association of findings on CCTA with subsequent treatment and control of CAD risk factors was assessed in 208 consecutive symptomatic outpatients without known CAD who underwent CCTA. Blood pressure (BP), lipid levels, and CAD medications were compared before and after CCTA (mean follow-up period 8.1 +/- 6.6 months). CAD severity on CCTA was graded as absent, mild (1% to 49%), moderate (50% to 69%), or severe (> or =70%) stenosis. In patients with absent, mild, moderate, and severe CAD on CCTA, aspirin was initiated in 0%, 14%, 36%, and 15%; statins were initiated or increased in 4%, 23%, 44%, and 42% of patients; and BP medications were initiated or increased in 16%, 10%, 26%, and 38% of patients (p <0.05 for severe vs no CAD for all). Higher grades of CAD severity were independently associated with greater post-CCTA use of aspirin (odds ratio 3.2 per grade, p <0.001) and statins (odds ratio 3.6 per grade, p <0.001), but not BP medications. Greater CAD severity was independently associated with lower post-test total cholesterol (-8.2 mg/dl per grade, p = 0.02), low-density lipoprotein cholesterol (-6.8 mg/dl per grade, p = 0.04), and diastolic BP (-1.4 mm Hg per grade, p = 0.03), but not systolic BP. In conclusion, greater CAD severity on CCTA is associated with enhanced medical treatment and improved control of CAD risk factors.

Atherosclerotic progression attenuates the expression of Nogo-B in autopsied coronary artery: pathology and virtual histology intravascular ultrasound analysis

The relation of Nogo-B to atherosclerotic plaque progression is not well understood. Thus, the purpose of this study was to assess the expression of Nogo-B in fibroatheromas (FA) of different stages, classified using virtual histology intravascular ultrasound (VH-IVUS) analysis in 19 autopsied cases of non-sudden cardiac death. VH-IVUS imaging analysis was performed 30 mm from the ostium of each coronary artery. VH-IVUS revealed 11 early FAs (34.5+/-8.3 yr), 12 late FAs (42.6+/-16.6 yr), 8 thick-cap FAs (TkCFAs) (46.4+/-11.1 yr), and 6 thin-cap FAs (TCFAs) (51.8+/-6.8 yr). TkCFAs and TCFAs were defined as advanced FA. FA progression advanced with age (P=0.04). VH-IVUS analysis of small, early FAs showed smaller necrotic cores and relatively less calcium compared to more advanced FAs with large necrotic cores (P<0.001). Histopathology and immunohistochemical stains demonstrated that early or late FAs had smaller necrotic cores, less empty space of decalcification, and greater Nogo-B expression compared to advanced FAs (vs. early FA, P=0.013; vs. late FA, P=0.008, respectively). These findings suggest that FA progression is inversely associated with Nogo-B expression. Local reduction of Nogo-B may contribute to plaque formation and/or instability.

Incremental prognostic value of multi-slice computed tomography coronary angiography over coronary artery calcium scoring in patients with suspected coronary artery disease

AIMS

The purpose of this study was to assess the relationship between calcium scoring (CS) and multi-slice computed tomography coronary angiography (MSCTA) and to determine if MSCTA has an incremental prognostic value to CS.

METHODS AND RESULTS

In 432 patients (59% male, age 58 +/- 11 years) referred for cardiac evaluation owing to suspected coronary artery disease (CAD), CS and 64-slice MSCTA were performed. The following events were combined in a composite endpoint: all-cause mortality, non-fatal infarction, and unstable angina requiring revascularization. CS was 0 in 147 (34%) patients, CS 1-99 was present in 122 (28%), CS 100-399 in 75 (17%), CS 400-999 in 56 (13%), and CS > or = 1000 in 32 (7%). MSCTA was normal in 133 (31%) patients, MSCTA 30-50% stenosis was observed in 190 (44%), and MSCTA > or =50% stenosis in 109 (25%). During follow-up [median 670 days (25th-75th percentile: 418-895)], an event occurred in 21 patients (4.9%). After multivariate correction for CS, MSCTA > or = 50% stenosis, the number of diseased segments, obstructive segments, and non-calcified plaques were independent predictors with an incremental prognostic value to CS.

CONCLUSION

MSCTA provides additional information to CS regarding stenosis severity and plaque composition. This additional information was shown to translate into incremental prognostic value over CS.

Coronary computed tomography and magnetic resonance imaging

Cardiac computed tomography and magnetic resonance are relatively new imaging modalities that can exceed the ability of established imaging modalities to detect present pathology or predict patient outcomes. Coronary calcium scoring may be useful in asymptomatic patients at intermediate risk. Computed tomographic coronary angiography is a first-line indication to evaluate congenitally abnormal coronary arteries and, along with stress magnetic resonance myocardial perfusion imaging, is useful in symptomatic patients with nondiagnostic conventional stress tests. Cardiac magnetic resonance is indicated for visualizing cardiac structure and function, and delayed enhancement magnetic resonance is a first-line indication for assessing myocardial viability. Imaging plaque and molecular mechanisms related to plaque rupture holds great promise for the presymptomatic detection of patients at risk for coronary events but is not yet suitable for routine clinical use.

Non-invasive assessment of vulnerable plaque

BACKGROUND

Sudden cardiac death or unheralded acute coronary syndromes are common initial manifestations of coronary atherosclerosis and most such events occur at sites of non-flow limiting coronary atherosclerosis.

OBJECTIVE

Non-invasive detection of high-risk plaques might provide a means to improve risk stratification in primary and secondary prevention settings.

METHODS

This review is focused on the potential of multidetector computed tomography coronary angiography (MDCT-CA) to provide the opportunity to identify different aspects of plaque vulnerability throughout the coronary tree in an accurate, fast, safe and non-invasive manner.

CONCLUSION

Coronary artery calcium scoring, on top of established risk stratification, could potentially be a cost-effective strategy for primary prevention. MDCT-CA allows a non-invasive evaluation of several features commonly seen in vulnerable plaques and has demonstrated an independent prognostic value on a patient basis. The value of the technique itself might result, potentially, in a better estimation of the relative risk of an invidual plaque to rupture.