Pharmaceutical therapy of hyperlipidemia is clearly beneficial. In the patient without established heart disease however, conventional risk assessment is imprecise and determining which patients are at highest versus lowest risk is a common clinical conundrum. It is well established that the most powerful determinant to risk is the overall extent/severity of coronary disease. Electron beam tomography (EBT) and quantification of coronary artery calcium has been shown to provide a valid non-invasive surrogate to atherosclerotic plaque burden. Screening patients who are considered to be at traditional intermediate to high risk by first using EBT can refine the broad-based population risk to a more individual basis. Data that is based upon a model developed for application of EBT are presented, which discuss its potential as a cost effective application to guide statin therapy in intermediate and high-risk sub-groups.
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2.
GroverSACoupalLHuXP.Identifying adults at increased risk of coronary disease. How well do the current cholesterol guidelines work?JAMA1995; 274: 801–806.
3.
This is a subset of the LRC (lipid research clinic) study. This was designed to assess the accuracy of lipid screening strategies to identify individuals at increased risk of coronary disease mortality. ROC curves were constructed using the current NCEP guidelines which include only LDL cholesterol, and the use of the total cholesterol to HDL level. They indicate that the TC/HDL ratio was more sensitive and only slightly less specific than the NCEP methods.
4.
SchmermundABaumgartDGörgeGGrönemeyerDSeibelRBaileyKR. Measuring the effect of risk factors on coronary atherosclerosis: coronary calcium score vs. angiographic disease severity. J Am Coll Cardiol1998; 31: 1267–1273.
5.
Risk factors indicate the risk of developing manifest heart disease sometime during life; however, based upon this information, they predict only about one-third of the severity of coronary disease as determined by anatomic testing such as coronary angiography and electron beam tomography. Despite the use of risk factors to determine the likelihood of developing disease, they do not predict where disease is or what its magnitude might be.
6.
FitzpatrickLASeversonAEdwardsWDIngramRT.Diffuse calcification in human coronary arteries: association of osteopontin with atherosclerosis. J Clin Invest1994; 94: 1597–1604.
7.
Human coronary arteries were examined for the presence and extent of mineralization (i.e. calcification, or more properly calcium hydroxyapatite). Hydroxyapatite was not found in normal coronary artery sections. Immunohistochemistry for osteopontin (a phosphorylated glycoprotein and an important component of bone regulation) indicated intense staining in all pathologically disease artery sections. It was speculated that non-collagenous proteins such as osteopontin regulate the presence or absence of calcification and ultimately alter vessel compliance. This is one of the first of several studies which indicate that the pathophysiology of coronary artery calcium formation is active, regulated, and part of the inflammatory cascade of developed and developing coronary artery plaque formation.
8.
RumbergerJASchwartzRSSimonsDBSheedyPFEdwardsWDFitzpatrickLA.Relations of coronary calcium determined by electron beam computed tomography and lumen narrowing determined at autopsy. Am J Cardiol1994; 73: 1169–1173.
9.
This study, like the one carried out by Mautner et al. [11], indicated that electron beam calcium score is related to the severity of lumenal disease, when studies are carried out on pathologic specimens.
10.
RumbergerJASheedyPFBreenJRSchwartzRS.Coronary calcium as determined by electron beam computed tomography, and coronary disease on arteriogram: effect of patient's sex on diagnosis. Circulation1995; 91: 1363–1367.
11.
RumbergerJASheedyPFBreenJFSchwartzRS.Electron beam CT coronary calcium score cutpoints and severity of associated angiography luminal stenosis. J Am Coll Cardiol1997; 29: 1542–1548.
12.
Although one cannot use the coronary artery calcium score to determine the severity of luminal obstructive disease, this study does give information regarding stenosis severity, determine by angiography, and sensitivity and specificity of various electron beam calcium scores.
13.
BudoffMKGeorgiouDBrodyAAgatstonASKennedyJWolfkielC. Ultrafast computed tomography as a diagnostic modality in the detection of coronary artery disease – a multicenter study. Circulation1996; 93: 898–904.
14.
KajinamiKSekiHTakehoshiNMabushiH.Noninvasive prediction of coronary atherosclerosis by quantification of coronary artery calcification using electron beam computed tomography: comparison with electrocardiographic and thallium exercise stress test results. J Am Coll Cardiol1995; 26: 1209–1221.
15.
RumbergerJASimonsDBFitzpatrickLASheedyPFSchwartzRS.Coronary artery calcium areas by electron beam computed tomography and coronary atherosclerotic plaque area: a histopathologic correlative study. Circulation1995; 92: 2157–2162.
16.
This study was the first to determine that electron beam tomography calcium area relates to the overall atherosclerotic plaque burden on a site-by-site, artery-by-artery, and heart-by-heart basis.
17.
MautnerSLMautnerGCFroehlichJFeuersteinIMProschanMARobertsWC. Coronary artery disease: prediction with in vitro electron beam CT. Radiology1994; 192: 625–630.
18.
This is a large study in pathologic specimens which compares electron beam tomography-derived images with histologic disease stenosis severity. This confirms and extends the earlier study from the Mayo Clinic (SimonsDBSchwartzRSEdwardsWDSheedyPFBreenJFRumbergerJA.Non-invasive definition of anatomic coronary artery disease by ultrafast CT: A quantitative pathologic study. J Am Coll Cardiol1992; 20: 1118–1126). Provides however additional information as to the distribution of coronary calcium in various coronary arteries.
19.
DetranoRTzungHWangSPuentesGFallavollitaJShieldsP. Prognostic value of coronary calcification and angiographic stenoses in patients undergoing coronary angiography. J Am Coll Cardiol1996; 27: 285–290.
20.
This study in a large group of patients with angiographically proven coronary disease was found to have additional prognostic data regarding event free survival as derived from the electron beam coronary calcium score.
21.
AradYSpadaroLAGoodmanKLledo-PerezAShermanS.LernerG. Predictive value of electron beam computed tomography of the coronary arteries – 19 month follow-up of 1173 asymptomatic patients. Circulation1996; 93: 1951–1953.
22.
This study examined asymptomatic patients who were at moderate risk for heart disease. In a 19-month follow-up, the severity of the electron beam tomography coronary calcium score was shown to be a very powerful predictor of subsequent coronary disease events (on the order of 10 times that of standard cholesterol measures).
23.
SecciAWongNTangWWangSDohertyTDetranoR.Electron beam computed tomographic coronary calcium as a predictor of coronary events: comparison of two protocols. Circulation1997; 96: 1122–1129.
24.
Scandinavian Simvastatin Survival Study Group.Randomized trial of cholesterol lowering in 4444 patients with coronary heart disease: the Scandinavian Simvastatin Survival Study (4S). Lancet1994; 344: 1383–1389.
25.
SacksFMPfefferMAMoyeLRouleauJRutherfordJColeT. The effect of pravastatin on coronary events after myocardial infarction in patients with average cholesterol levels. N Engl J Med1996; 335: 1001–1009.
26.
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27.
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28.
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29.
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31.
ProudfitWLBruschkeAVSonesFW.Clinical course of patients with normal or slightly or moderately abnormal coronary arteriograms: 10 year follow-up of 521 patients. Circulation1980; 62: 712–717.
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ProudfitWJBruschkeAVMacMillanJPWilliamsGWSonesFW.Fifteen-year survival of patients with obstructive coronary artery disease. Circulation1983; 68: 986–997.
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LichtlenPR.Natural history of coronary artery disease based on coronary angiograms: a critical review. Cleve Clin Q1978; 45: 153–155.
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35.
RumbergerJASheedyPFBreenJFSchwartzRS.Electron beam CT coronary calcium score outpoints and severity of associated angiography luminal stenosis. J Am Coll Cardiol1997; 29: 1542–1548.
36.
AgatstonASJanowitzWRHildnerFJZusmerNRViamonteMDetranoR.Quantification of coronary artery calcium using ultrafast computed tomography. J Am Coll Cardiol1990; 15: 827–832.
37.
LevyDWilsonPWAndersonKMCastelliWP.Stratifying the patient at risk from coronary disease: new insights from the Framingham Heart Study. Am Heart J1990; 119: 712–717.
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VargasCMBurtVKGillamRF.Cardiovascular disease in NHANES III. Ann Epidemiol1997; 7: 523–525.
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RumbergerJABrundageBHRaderDJKondosG.Electron beam CT coronary calcium scanning: a review and guidelines for use in asymptomatic individuals. Mayo Clinic Proc1999; 74: 243–252.
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