(Circulation. 1997;96:1122-1129.)
© 1997 American Heart Association, Inc.
Articles |
Electron Beam Computed Tomographic Coronary Calcium as a Predictor of Coronary Events
Comparison of Two Protocols
From Harbor-UCLA Medical Center, Saint John's Cardiovascular Research Institute, Torrance, Calif.
Correspondence to Robert Detrano, MD, PhD, Harbor-UCLA Medical Center, 1124 W Carson St, Bldg RB-2, Torrance, CA 90502.
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Abstract |
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Background We assessed the accuracy of two electron beam computed tomography (EBCT) protocols for predicting coronary events.
Methods and Results In 1994, 24 months after enrollment in a longitudinal study, 326 high-risk adults underwent both 3- and 6-mm image-slice thickness EBCT scanning and were followed up for 32.0±4.0 additional months. Events were defined as either coronary death, myocardial infarction, or revascularization. We monitored these subjects for the 32-month postscanning period with yearly phone calls and acquisition of records for all hospital admissions. At the time of scanning, 11 subjects (3%) had already suffered 12 events (5 infarctions and 7 revascularizations) during the 24-month prescanning period. During the postscanning period, 18 subjects (6%) suffered 23 events (5 coronary deaths, 6 infarctions, and 12 revascularizations). Thus, 28 subjects (9%) suffered 35 events. Calcium quantities calculated for both protocols, performed on the same subjects, were sorted in ascending order and divided into equal quartiles. When revascularizations were included, there was a significant trend toward higher frequencies of events with increasing calcium quantity (P<.01). However, coronary death and infarction were not significantly more frequent in higher quartiles. These relationships were preserved in the subjects without prior events at the time of scanning.
Conclusions Calcium quantities from the 3-mm and the more reproducible 6-mm scanning are equally accurate for predicting events. Coronary calcium amount appears to be a weak predictor of coronary death and infarction. Its predictive accuracy is superior for predicting revascularization.
Key Words: calcium • coronary disease • tomography • revascularization
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Introduction |
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The potential prognostic value of radiographically detectable coronary calcium has inspired great interest and some controversy.1 2 3 4 5 Some investigators have found a high predictive value of coronary calcium for coronary heart disease events in asymptomatic subjects.1 Others4 6 7 have expressed doubts regarding its predictive value, mostly because of the high prevalence of this finding in the general population8 and because of the uncertainty regarding the contribution of calcium to the probability of plaque rupture.9
The South Bay Heart Watch Cohort consists of 1461 subjects at high risk for coronary disease events who had neither experienced symptoms of coronary heart disease nor exhibited ECG evidence of prior infarction at the time of enrollment.8 10 Our initial findings using fluoroscopy demonstrated that both the presence of coronary calcium and the number of calcified vessels predict coronary events (defined as myocardial infarction, coronary death, and revascularization). Notably, however, 31% of subjects suffering infarction or coronary death had no coronary calcium detectable by fluoroscopy.
Such an imperfection in the predictive accuracy of the test may be due to factors involving the technical inferiority of fluoroscopy compared with EBCT. However, compelling evidence indicates that the pathological substrate of hard coronary events (infarction and sudden death) is plaque rupture,11 and it is unclear whether calcified plaques are more or less likely to rupture than noncalcified plaques.6 Although extensive calcification probably signifies extensive disease and the quantity of calcification roughly correlates with the quantity of atherosclerosis,12 13 calcification of individual plaques may imply plaque stability rather than instability.6 14 15
The results reported herein suggest that coronary calcific deposits, assessed with either 3- or 6-mm slice-thickness EBCT scans, predict coronary events in high-risk subjects when revascularization is included as an end point. However, serious coronary events may be common in subjects with little or no coronary calcium.
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Methods |
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Study Sample
All 1461 subjects originally enrolled by the South Bay Heart Watch were asymptomatic at enrollment and had an 8-year Framingham Study risk of a coronary heart disease event that exceeded 10%.16 We recruited this cohort in the following manner. We evaluated 5023 subjects between December 1990 and December 1992. These subjects were
45 years of age and had at least one
coronary risk factor. We recruited them through newspaper and
radio advertising and direct mail campaigns. A nurse administered an
angina questionnaire and performed a risk factor evaluation. We
excluded subjects with a history of prior myocardial infarction or
angina. The nurse used the risk factor information to calculate the risk of coronary events during an 8-year period according to the Framingham risk calculation algorithm16 and excluded subjects found to have a <10% risk. We enrolled the remaining 1461 subjects (29%) and invited them to return for follow-up visits after 1 and 2 years.
At the second of these follow-up visits, we asked the first 362 of these subjects to undergo a second risk factor evaluation for coronary calcification. The study sample of the present report consisted of the 326 consecutive volunteer subjects who agreed to return, undergo multiple testing, and be followed up for an additional 32 months. Risk factor evaluations, ECGs, and medication evaluations were done twice: at the time of recruitment into the study and 2 years later within 1 week before EBCT examination.
We considered family history of coronary disease to be pertinent if a first-degree relative had suffered a myocardial infarction, had died suddenly, or had undergone revascularization before the age of 65 years. We assessed history of smoking by asking subjects if they had ever smoked more than 10 cigarettes a day for at least 1 year. Diabetes or hypertension was considered present if a subject received dietary or medical therapy or both for these disorders. We measured height to the nearest half inch and weight to the nearest half pound. Body mass index was calculated as weight divided by the square of the height. The nurse recorded all relevant medication intake, including aspirin, ß-blocking agents, other antihypertensive agents, and hypolipidemic agents.
We measured systolic and diastolic blood
pressures with a mercury sphygmomanometer twice at 3-minute intervals
while the subjects were sitting for 5 minutes. Measurements differed by
3.4±7.8 and 0.4±0.5 mm Hg, respectively. We sampled blood from
an arm vein after a 12-hour fast with subjects in a sitting position.
Samples were allowed to coagulate at room temperature. We used the
cholesterol oxidase technique to measure total
cholesterol levels and measured HDL cholesterol
after precipitation of the LDLs. We recorded ECGs with the subjects
in a supine position to evaluate the presence of left
ventricular hypertrophy. A Romhilt-Estes
score17 of 4 defined left ventricular
hypertrophy. Three blinded cardiologists read all ECGs and
resolved differences of opinion by consensus.
EBCT
We obtained EBCT results using an Imatron C-100 scanner.
Scanning was done using a standard thin-slice protocol with 3-mm image
slices and again with a more reproducible18 thick-slice
protocol using 6-mm slices. Exposure time was 100 ms/image slice, and
total skin radiation was <6 mGy/scan. ECG triggering was used so that
image acquisition occurred after 80% of the RR interval. Transverse
image slices of the heart were obtained contiguously beginning 1 cm
below the carina and progressing caudally.
The EBCT scanner was examined by a physicist and was found to function without interslice gaps or overlaps. A standard calibration phantom19 20 was placed under each subject. This allowed calculation of calibrated mass estimates of hydroxyapatite content in each coronary artery.
Image Analysis
Each scan was examined by a cardiologist experienced in both
coronary angiography and tomographic imaging. The area of each
pixel was 0.34 mm2. An ROI 66 mm2 in
area19 20 was created that was precisely centered on each
focus of possible coronary calcification, defined as a volume
of 8.16 mm3 with a CT number >130 HU21
within the distribution of a coronary artery. The mean and peak
CT numbers and the area of the subsets of pixels with CT numbers >130
HU and >0 HU within these regions were calculated. Two indices of
calcification were assessed for each scan: the coronary calcium
score22 and the estimated calcium phosphate
mass.20 The coronary calcium score was calculated
for each artery as follows:
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peak CT number200 HU, 2 if 200
HUpeak CT number300 HU, 3 if 300 HUpeak CT number400 HU, and 4
if 400 HUpeak CT number; and T is the slice thickness.
The estimated mass of calcium phosphate was calculated for each artery
by use of the arterial summation (AS) as
follows19 20 :
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Clinical Follow-up
All 326 subjects had been asymptomatic at
enrollment. At the 1- and 2-year clinic visits, we assessed clinical
coronary heart disease using a medical history questionnaire
and review of medical records. The second follow-up visit consisted
of a clinical assessment as well as a risk factor evaluation and an
EBCT scan. At 12, 24, and 32 months after these scans, a research
assistant contacted all participants by telephone. At each of these
points in time, we assessed coronary heart disease using
questions concerning intervening symptoms and hospital admissions.
We considered a follow-up attempt successful when surviving subjects either returned to the clinic or completed a telephone interview and all relevant medical records were obtained. For deceased subjects, we defined successful follow-up as the procurement of relevant medical records, transcribed conversation with next of kin, death certificate, and autopsy report when available. Follow-up was successfully completed in 99% of cases, and records were obtained for all hospitalizations. A committee of three board-certified cardiologists reviewed medical records and transcripts of conversations with next of kin, without knowledge of other data, to determine the occurrence of myocardial infarction or coronary heart disease death.
Statistical Analysis
Since indices of coronary calcium quantity were
not normally distributed, we reported medians and ranges as well as
means and SDs and performed log transformations
[log10(quantity+1)] for all parametric tests.
Scores and masses for each of the two protocols were sorted in
ascending order, and the 
2 test for trends was
used to determine if distributions of events in ascending quartiles had
a significant trend. Logistic regression was used to determine the
effect of log calcium score on event probability, independent of
standard risk factors.
We constructed ROC curves for predicting coronary heart disease events (including revascularization) for both the 3- and 6-mm scan protocols. We also constructed these curves for hard events (coronary death or infarction) and revascularization separately using the 3-mm scan protocol. We compared areas under the curves using the method of Hanley and McNeil.23
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Results |
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Patient Characteristics
Three hundred twenty-four of the 326 subjects who underwent scanning were followed up for 32.0±4.0 months after the scans. Their mean age was 66±8 years; 82% were men. Table 1
shows
the demographics and risk factors for these subjects. All patients had
at least two risk factors, and the mean coronary risk
(calculated from the Framingham risk equation for an event in 10 years)
was 19±9%. Relevant medications were divided into four categories, as
shown in Table 2.
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Five subjects had already suffered acute myocardial infarctions before their coronary calcium scans, and 7 had undergone revascularizations before their scans. Because 1 infarction had occurred in a subject with subsequent revascularization, there were 12 coronary heart disease events occurring in 11 subjects within the 24-month period before scanning.
Twenty-three coronary heart disease events occurred in 18 subjects during the 32-month period after scanning. These postscan events included 5 coronary deaths, 6 acute infarctions (1 fatal), and 12 coronary revascularizations. During the entire period embracing their scan dates, 28 subjects suffered 35 coronary events.
EBCT Scans
Table 3 shows calcium scores and masses using both
protocols. As has been previously described,20 6-mm scans
result in slightly lower masses and scores.
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Predictive Value of Coronary Calcium
Events were at least three times as frequent in subjects with
coronary calcium scores or mass above the median by both
scanning protocols (P<.01). Table 4 shows
the distribution by quartiles of coronary calcium score and
mass for coronary heart disease events, with both hard events
(myocardial infarction and coronary heart disease deaths) and
soft events (coronary revascularizations)
included. There was a very significant trend toward a greater frequency
of events for subjects with higher coronary calcium quantity
(P<.01 for both scanning protocols and both calcium mass
and score).
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Fig 1 shows the ROC curves for predicting any event for
the 3- and 6-mm scan protocols. There is no significant difference in
the areas under the curves, indicating identical accuracy of both scan
protocols in predicting events.
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Hard Versus Soft Events
Before Scanning
Table 5 shows the distribution of subjects with
infarctions and revascularizations occurring within
the 24-month period before scanning by quartiles of calcium scores and
calcium masses. There was no significant trend in infarctions, but
there was a significant upward trend in
revascularizations (P.01) as calcium
quantity increased for both calcium indices (score and mass) and both
protocols. Coronary events were distributed equivalently over
quartiles for the 3- and 6-mm scan protocols and for both calcium
indices. Fig 2 shows the ROC curves for predicting
subjects who had infarctions and revascularizations
during the 24-hour period preceding scanning. The area under the curve
for predicting revascularizations is significantly
greater than that for predicting infarctions (P=.004).
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After Scanning
Table 6 shows the distribution of subjects with
hard events (infarctions and coronary deaths) and
revascularizations occurring during the 32-month
period after scanning by quartiles of calcium scores and calcium
masses. Here we see no significant trend in hard events as calcium
quantities increase. However, the frequency of
revascularizations increases significantly as
calcium quantities increase for both the 3- and 6-mm scans
(P<.01).
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Table 7 shows the distributions of hard events and
revascularizations for subjects who were
asymptomatic (without prior events) when scanned. The
increasing frequency of revascularizations with
increasing calcium quantity and the lack of a significant association
with hard events are preserved for this subset of patients. Fig 3 shows the ROC curves for predicting
revascularization and hard events after scanning
for subjects asymptomatic at scanning. The area under the
curve for predicting revascularizations is
significantly greater than that for predicting hard events
(P=.05).
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Before and After Scanning
Table 8 shows the distribution of hard events and
revascularizations during the 24-month period
before and the 32-month period after scanning by quartiles of calcium
score and mass. Here, too, only the frequency of
revascularization increased significantly with
quartile for both indices and both protocols. Fig 4
shows the ROC curves for predicting
revascularization and hard events using the 3-mm
scan protocol. Prediction of revascularization by
use of EBCT is superior to its use for the prediction of hard end
points (P=.0009).
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Adjusting for Risk Factors
Table 9 shows the logistic regression coefficients,
odds ratios, and CIs for the prediction of hard coronary events
and revascularizations in the 32 months after
scanning. Notably, the log-transformed calcium score does not enter the
logistic regression model as a significant independent predictor of
hard coronary events. It is, however, a significant and
independent predictor of revascularizations. On the
other hand, only left ventricular hypertrophy
by ECG is independently and significantly related to hard
coronary events during the period after scanning.
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Table 10 shows the logistic regression coefficients,
odds ratios, and CIs for predicting events before and after the scan.
Only ECG evidence of left ventricular
hypertrophy predicts hard coronary events in this
period, whereas log calcium score and history of diabetes are
significant predictors of revascularization.
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Discussion |
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The results presented herein indicate that both 3-mm and the simpler and more reproducible 6-mm scanning protocols18 have identical accuracy for predicting coronary events (Fig 1
). In addition, coronary calcium
predicts coronary events when
revascularizations are included with hard
coronary end points (coronary death and myocardial
infarction). Coronary calcium was significantly related to
revascularizations, whether they occurred before
scanning or during subsequent follow-up. However, its predictive
accuracy is greatly reduced when hard events are used as end
points. Although it has been proposed that EBCT may be useful for prospectively identifying high-risk subjects, studies conducted with asymptomatic patients are scarce and show conflicting results.1 24 25 26 27 Our cohort included only 11 patients who had already suffered events and was thus composed predominantly (97%) of asymptomatic subjects at high risk of coronary heart disease. The present investigation involves the highest number of hard coronary end points (infarction and coronary death) of all reports to date. It also includes significant numbers of revascularizations done both before and after scanning. The results clearly show that subjects with little or no coronary calcium detected by EBCT can suffer coronary heart disease death and myocardial infarction. The results also demonstrate that revascularizations are more frequently performed for patients with than for those without coronary calcification. This raises the question of why subjects without coronary calcification have a significant likelihood of suffering infarctions or death but a lower likelihood of undergoing revascularization.
Most pathophysiological studies have shown that the mechanism of sudden death and myocardial infarction is usually plaque rupture,11 28 with the underlying substrate of coronary atherosclerosis. However, it is conceivable that both infarction and death could have had other mechanisms in our subjects. Sudden death judged to have been caused by coronary disease by our adjudication committee might have been due to primary arrhythmias or other noncoronary causes. Because autopsies were not performed, this possibility cannot be excluded. However, the bulk of the literature based on pathological data supports coronary atherosclerosis as the cause of sudden death in the overwhelming majority of cases.29 30 31 32 33 34
It is also possible that severe atherosclerosis without calcification existed in our asymptomatic subjects who suffered hard coronary events. A small percentage (5%) of subjects with proven severe atherosclerosis by angiography have been found not to have detectable coronary calcification by EBCT.35 Additionally, we have noted two cases of proven severe atherosclerosis in patients who suffered hard coronary events but did not have radiographically detectable coronary calcification.10 35
This raises the interesting possibility that under certain
circumstances, noncalcific plaques may be more likely to rupture than
those containing calcium. Analysis of the biomechanical
properties of atherosclerotic plaques suggests that calcified lesions
are more resistant to rupture than noncalcified
plaques,14 and results from the FATS study36
indicate that the primary benefit of lipid-lowering therapy is not
regression of atherosclerosis but stabilization of
existing lesions by lowering their lipid content. In a prospective
study of asymptomatic patients with carotid artery
atherosclerosis, Johnson et al34 showed
that patients with ultrasonically detectable carotid calcium are much
less likely to suffer symptomatic cerebral events than
those with no detectable carotid calcium despite the severity of
stenosis. More recent studies have also shown an association
between carotid artery plaque composition and symptomatic
cerebral ischemia.37 38 Kragel et
al,39 in a postmortem study of 27 hearts, found that
ruptured plaques tended to contain more lipid and less fibrous tissue
and calcium than those that had not ruptured. Our finding of an
association between coronary calcium and
revascularization may also be explained by the
stability of calcified lesions that lead to more stable and less
catastrophic symptoms and thus allow
revascularization to be performed before the
occurrence of more serious events. It is also possible that a report of
an abnormal computed tomographic result might have increased the
likelihood of referral for
revascularization.40 However, research
staff explained to the participants that the clinical significance of
coronary calcium was as yet unknown, and no attempt was made to
directly communicate EBCT results to their personal physicians. Also,
examination of Tables 5, 6, and 7 similarly shows that the likelihood
of revascularizations increases with higher calcium
quantity either before or after EBCT scanning. This fact makes referral
bias an unlikely cause for the observed increase in the incidence of
revascularization, with greater quantities of
calcium detected by use of EBCT.
Both the standard 3-mm-thick and the more reproducible 6-mm-thick slice protocols (which we have developed and researched in our laboratory) gave similar distributions of coronary events in ascending quartiles of scores and coronary masses. Because the thick-slice studies can be analyzed more quickly and more easily and have a higher interscan reproducibility,18 we recommend that this protocol be used in all research regarding coronary screening. This would greatly reduce cost and simplify coronary screening research.
The cohort of subjects that we studied were of very high risk for suffering coronary events. It is possible, however, that coronary calcium would be a predictor of infarction and death in low-risk individuals. The results presented here indicate that more research is needed before this clinical screening is approved by the medical community.
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Selected Abbreviations and Acronyms |
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Acknowledgments |
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This study was supported by an NHLBI grant, No. 5-ROI-HL-43277-06, and a grant from Saint John's Heart Institute. Particular gratitude must be extended to Drs Bruce Brundage, Kenneth Narahara, Demetrios Georgiou, and William French for their assistance as part of the ECG reading and adjudication committees. Dr Brundage provided institutional support as well. The nursing support of Oleh Brezden and Gail Puentes is deeply appreciated. Eddie F. Rodrigues and Ramon M. Valencia provided technical and editorial assistance.
Received January 2, 1997; revision received March 14, 1997; accepted March 18, 1997.
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References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
-
Wong ND, Abrahamson D, Tran H, Eisenberg H,
Detrano RC. Coronary calcium quantity assessed by
electron beam CT: relation to new coronary events.
Circulation. 1995;91(suppl I):I-934. Abstract.
-
Detrano RC. Why the controversy about electron
beam computed tomography screening for coronary
atherosclerosis? Br Heart J. 1994;72:313-314. Editorial.
[Free Full Text]
-
Baron MG. Significance of coronary
artery calcification. Radiology. 1994;192:613-614.
[Free Full Text]
-
Fallavollita JA, Brody AS, Bunnell IL, Kumar K, Canty
JM Jr. Fast computed tomography detection of coronary
calcification in the diagnosis of coronary artery disease:
comparison with angiography in patients <50 years old. J Am
Coll Cardiol. 1993;21:54A.
-
Loecker TH, Schwartz RS, Cotta CW, Hickman JR.
Fluoroscopic coronary artery calcification and associated
coronary disease in asymptomatic young men.
J Am Coll Cardiol. 1992;19:1167-1172.[Abstract]
-
Wexler L, Brundage B, Crouse J, Detrano R, Fuster V,
Maddahi J, Rumberger J, Stanford W, White R, Taubert K.
Coronary artery calcification: pathophysiology,
epidemiology, imaging methods, and clinical
implications—a statement for health professionals from the American
Heart Association. Circulation. 1996;94:1175-1192.
[Free Full Text]
-
Schwartz RS. Coronary artery
calcification and prognosis: same song, second verse?
J Am Coll Cardiol. 1994;24:359-361. Editorial.[Medline]
[Order article via Infotrieve]
-
Detrano RC, Wong ND, French WJ, Tang W, Georgiou D,
Young E, Brezden OS, Doherty T, Brundage BH. Prevalence of
fluoroscopic coronary calcific deposits in high-risk
asymptomatic persons. Am Heart J. 1994;127:1526-1532.[Medline]
[Order article via Infotrieve]
-
Friedrich GJ, Hausmann D, Fitzgerald PJ, Yock
PG. Prognostic value of coronary calcification,
II. J Am Coll Cardiol. 1996;28:284. Letter.[Medline]
[Order article via Infotrieve]
-
Detrano RC, Wong ND, Tang W, French WJ, Georgiou D,
Young E, Brezden OS, Doherty TM, Narahara KA, Brundage BH.
Prognostic significance of cardiac cinefluoroscopy for coronary
calcific deposits in asymptomatic high risk
subjects. J Am Coll Cardiol. 1994;24:354-358.[Abstract]
-
Fuster V, Badimon L, Badimon JJ, Chesebro JH.
The pathogenesis of coronary artery disease and the acute
coronary syndromes, II. N Engl J
Med. 1992;326:310-318.[Medline]
[Order article via Infotrieve]
-
Mautner GC, Mautner SL, Froehlich J, Feuerstein IM,
Proschan MA, Roberts WC, Doppman JL. Coronary artery
calcification: assessment with electron beam CT and histomorphometric
correlation. Radiology. 1994;192:619-623.
[Abstract/Free Full Text]
-
Mautner SL, Mautner GC, Froehlich J, Feuerstein IM,
Proschan MA, Roberts WC, Doppman JL. Coronary artery
disease: prediction with in vitro electron beam CT.
Radiology. 1994;192:625-630.
[Abstract/Free Full Text]
-
Cheng GC, Loree HM, Kamm RD, Fishbein MC, Lee
RT. Distribution of circumferential stress in ruptured and
stable atherosclerotic lesions: a structural analysis with
histopathological correlation. Circulation. 1993;87:1179-1187.
[Abstract/Free Full Text]
-
Doherty TM, Detrano RC. Coronary
arterial calcification as an active process: a new
perspective on an old problem. Calcif Tissue Int. 1994;54:224-230.[Medline]
[Order article via Infotrieve]
-
Anderson K, Wilson P, Odell P, Kannel W. An
updated coronary risk profile. Circulation. 1991;83:356-363.
[Free Full Text]
-
Romhilt DW, Estes EH Jr. A point score system for the
ECG diagnosis of left ventricular hypertrophy.
Am Heart J. 1968;75:752-758.[Medline]
[Order article via Infotrieve]
-
Wang S, Detrano RC, Tang W, Doherty TM, Puentes G, Wong
N, Brundage BH. Detection of coronary calcification with
electron beam computed tomography: evaluation of inter-examination
reproducibility and comparison of three image acquisition
protocols. Am Heart J. 1996;132:550-558.[Medline]
[Order article via Infotrieve]
-
Mahaisavariya P, Detrano RC, Kang X, Garner D, Vo A,
Georgiou D, Molloi S, Brundage BH. Quantitation of in vitro
coronary artery calcium using ultrafast computed
tomography. Cathet Cardiovasc Diagn. 1994;32:387-393.[Medline]
[Order article via Infotrieve]
-
Detrano RC, Kang X, Mahaisavariya P, Tang W, Colombo A,
Molloi S, Garner D, Nickerson S. Accuracy of quantifying
coronary hydroxyapatite with electron beam tomography.
Invest Radiol. 1994;29:733-738.[Medline]
[Order article via Infotrieve]
-
Bielak LF, Kaufmann RB, Moll PP, McCollough CH,
Schwartz RS, Sheedy PF II. Small lesions in the heart identified
at electron beam CT: calcification or noise?
Radiology. 1994;192:631-636.
[Abstract/Free Full Text]
-
Agatston AS, Janowitz WR, Hildner FJ, Zusmer N,
Viamonte M, Detrano RC. Quantification of coronary
artery calcium using ultrafast computed tomography.
J Am Coll Cardiol. 1990;15:827-832.[Abstract]
-
Hanley JA, McNeil BJ. A method of comparing the
areas under receiver operating characteristic curves derived from the
same cases. Radiology. 1983;148:839-843.
[Abstract/Free Full Text]
-
Balogh T, Hoff J, Rich S, Wolfkiel CJ.
Development of coronary artery disease in
asymptomatic patients undergoing coronary artery
calcification screening by electron beam tomography.
Circulation. 1995;92(suppl I):I-650. Abstract.
-
Arad Y, Spadaro LA, Goodman K, Lledo-Perez A, Sherman
S, Lerner G, Guerci AD. The predictive value of electron beam CT
of the coronary arteries: 19-month follow-up of 1173
asymptomatic patients. Circulation. 1996;93:1951-1953.
[Abstract/Free Full Text]
-
Hudson NM, Walker JK. The prognostic
significance of coronary artery calcification seen on
fluoroscopy. Clin Radiol. 1976;27:545-547.[Medline]
[Order article via Infotrieve]
-
Puentes G, Detrano RC, Tang W, Wong N, French W,
Narahara K, Brundage BH, Baksheshi H. Estimation of
coronary calcium mass using electron beam computed tomography:
a promising new approach for predicting coronary
events? Circulation. 1995;92(suppl I):I-313.
Abstract.
-
Farb A, Tang AL, Burke AP, Sessums L, Liang Y, Virmani
R. Sudden coronary death: frequency of active
coronary lesions, inactive coronary lesions, and
myocardial infarctions. Circulation. 1995;92:1701-1709.
[Abstract/Free Full Text]
-
Gillum RF. Sudden coronary death in the
United States: 1980-1985. Circulation. 1989;79:756-765.
[Abstract/Free Full Text]
-
Humphries JO, Kuller L, Russ RS, Friesinger GC,
Page EE. Natural history of ischemic heart disease in
relation to arteriographic findings: a 12-year study of 224
patients. Circulation. 1974;49:489-497.
[Abstract/Free Full Text]
-
Madsen JK. Ischaemic heart disease and prodromes
of sudden cardiac death: is it possible to identify high risk groups
for sudden cardiac death? Br Heart J. 1985;54:27-32.
[Abstract/Free Full Text]
-
Myerburg RJ, Kessler KM, Castellanos A. Sudden
cardiac death: epidemiology, transient risk,
and intervention assessment. Ann Intern Med. 1993;119:1187-1197.
[Abstract/Free Full Text]
-
Roberts WC, Putkin BN, Solus DE, Reddy SG. Mode
of death, frequency of healed and acute myocardial infarction, number
of major epicardial coronary arteries severely narrowed by
atherosclerotic plaque, and heart weight in fatal atherosclerotic
coronary artery disease: analysis of 889 patients
studied at necropsy. J Am Coll Cardiol. 1990;15:194-203.[Medline]
[Order article via Infotrieve]
-
Johnson JM, Kennelly M, Decesare D, Morgan S, Sparrow
A. Natural history of asymptomatic carotid
plaque. Arch Surg. 1985;120:1010-1012.[Abstract]
-
Detrano RC, Hsiai T, Wang S, Puentes G, Fallavollita J,
Shields P, Stanford W, Wolfkiel C, Georgiou D, Budoff M, Reed J.
Prognostic value of coronary calcification and angiographic
stenosis in patients undergoing coronary
arteriography. J Am Coll Cardiol. 1996;27:285-290.[Abstract]
-
Brown G, Albers JJ, Fisher LD, Schaefer SM, Lin JT,
Kaplan C, Zhao XQ, Bisson BS, Fitzpatrick VF, Dodge HT.
Regression of coronary artery disease as a result of intensive
lipid-lowering therapy in men with high levels of apolipoprotein
B. N Engl J Med. 1990;323:1289-1298.[Abstract]
-
Iannuzzi A, Wilcosky T, Mercuri M, Rubba P, Bryan FA,
Bond G. Ultrasonographic correlates of carotid
atherosclerosis in transient ischemic attack
and stroke. Stroke. 1995;26:614-619.
[Abstract/Free Full Text]
-
Langsfeld M, Gray-Weale AC, Lusby RJ. The role
of plaque morphology and diameter reduction in the development of new
symptoms in asymptomatic carotid arteries. J
Vasc Surg. 1989;9:548-557.[Medline]
[Order article via Infotrieve]
-
Kragel AH, Reddy SG, Wittes JT, Roberts WC.
Morphometric analysis of the composition of atherosclerotic
plaques in the four major coronary arteries in acute myocardial
infarction and in sudden coronary death.
Circulation. 1989;80:1747-1756.
[Abstract/Free Full Text]
-
Detrano RC. Predictive value of EBCT.
Circulation. 1997;95:601. Letter.
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  A. Rutten, I. Isgum, and M. Prokop Coronary Calcification: Effect of Small Variation of Scan Starting Position on Agatston, Volume, and Mass Scores Radiology, December 1, 2007; 246(1): 90 - 98. [Abstract] [Full Text] [PDF]
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 O. Leontiev and T. J. Dubinsky CT-Based Calcium Scoring to Screen for Coronary Artery Disease: Why Aren't We There Yet? Am. J. Roentgenol., November 1, 2007; 189(5): 1061 - 1063. [Abstract] [Full Text] [PDF]
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 C. M. Loria, K. Liu, C. E. Lewis, S. B. Hulley, S. Sidney, P. J. Schreiner, O. D. Williams, D. E. Bild, and R. Detrano Early Adult Risk Factor Levels and Subsequent Coronary Artery Calcification: The CARDIA Study J. Am. Coll. Cardiol., May 22, 2007; 49(20): 2013 - 2020. [Abstract] [Full Text] [PDF]
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 T. K Mittal, M. Barbir, and M. Rubens Role of computed tomography in risk assessment for coronary heart disease. Postgrad. Med. J., October 1, 2006; 82(972): 664 - 671. [Abstract] [Full Text] [PDF]
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 M. E. Clouse, J. Chen, H. M. Krumholz, M. E. Clouse, J. Chen, and H. M. Krumholz Noninvasive Screening for Coronary Artery Disease With Computed Tomography Is Useful Circulation, January 3, 2006; 113(1): 125 - 146. [Full Text] [PDF]
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 M. J. LaMonte, S. J. FitzGerald, T. S. Church, C. E. Barlow, N. B. Radford, B. D. Levine, J. J. Pippin, L. W. Gibbons, S. N. Blair, and M. Z. Nichaman Coronary Artery Calcium Score and Coronary Heart Disease Events in a Large Cohort of Asymptomatic Men and Women Am. J. Epidemiol., September 1, 2005; 162(5): 421 - 429. [Abstract] [Full Text] [PDF]
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 P.-H. Huang, L.-C. Chen, H.-B. Leu, P. Y.-A. Ding, J.-W. Chen, T.-C. Wu, and S.-J. Lin Enhanced Coronary Calcification Determined by Electron Beam CT Is Strongly Related to Endothelial Dysfunction in Patients With Suspected Coronary Artery Disease Chest, August 1, 2005; 128(2): 810 - 815. [Abstract] [Full Text] [PDF]
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 C. Iribarren, M. D. Gross, J. A. Darbinian, D. R. Jacobs Jr, S. Sidney, and C. M. Loria Association of Lipoprotein-Associated Phospholipase A2 Mass and Activity With Calcified Coronary Plaque in Young Adults: The CARDIA Study Arterioscler. Thromb. Vasc. Biol., January 1, 2005; 25(1): 216 - 221. [Abstract] [Full Text] [PDF]
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 M. Gross, M. Steffes, D. R. Jacobs Jr, X. Yu, L. Lewis, C. E. Lewis, and C. M. Loria Plasma F2-Isoprostanes and Coronary Artery Calcification: The CARDIA Study Clin. Chem., January 1, 2005; 51(1): 125 - 131. [Abstract] [Full Text] [PDF]
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P. Schoenhagen, S. S. Halliburton, A. E. Stillman, S. A. Kuzmiak, S. E. Nissen, E. M. Tuzcu, and R. D. White Noninvasive Imaging of Coronary Arteries: Current and Future Role of Multi-Detector Row CT Radiology, July 1, 2004; 232(1): 7 - 17. [Abstract] [Full Text] [PDF]
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U. J. Schoepf, C. R. Becker, B. M. Ohnesorge, and E. K. Yucel CT of Coronary Artery Disease Radiology, July 1, 2004; 232(1): 18 - 37. [Abstract] [Full Text] [PDF]
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 M. J. Pletcher, J. A. Tice, M. Pignone, and W. S. Browner Using the Coronary Artery Calcium Score to Predict Coronary Heart Disease Events: A Systematic Review and Meta-analysis Arch Intern Med, June 28, 2004; 164(12): 1285 - 1292. [Abstract] [Full Text] [PDF]
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 Y. Miwa, M. Tsushima, H. Arima, Y. Kawano, and T. Sasaguri Pulse Pressure Is an Independent Predictor for the Progression of Aortic Wall Calcification in Patients With Controlled Hyperlipidemia Hypertension, March 1, 2004; 43(3): 536 - 540. [Abstract] [Full Text] [PDF]
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 P. Greenland, L. LaBree, S. P. Azen, T. M. Doherty, and R. C. Detrano Coronary Artery Calcium Score Combined With Framingham Score for Risk Prediction in Asymptomatic Individuals JAMA, January 14, 2004; 291(2): 210 - 215. [Abstract] [Full Text] [PDF]
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 L. C. Gallo, W. M. Troxel, L. H. Kuller, K. Sutton-Tyrrell, D. Edmundowicz, and K. A. Matthews Marital Status, Marital Quality, and Atherosclerotic Burden in Postmenopausal Women Psychosom Med, November 1, 2003; 65(6): 952 - 962. [Abstract] [Full Text] [PDF]
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J. A. Rumberger and L. Kaufman A Rosetta Stone for Coronary Calcium Risk Stratification: Agatston, Volume, and Mass Scores in 11,490 Individuals Am. J. Roentgenol., September 1, 2003; 181(3): 743 - 748. [Abstract] [Full Text] [PDF]
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 K. Watanabe, T. Hiroki, and N. Koga Relation of Thoracic Aorta Calcification on Computed Tomography and Coronary Risk Factors to Obstructive Coronary Artery Disease on Angiography Angiology, July 1, 2003; 54(4): 433 - 441. [Abstract] [PDF]
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 K Pohle, D Ropers, R Maffert, P Geitner, W Moshage, M Regenfus, M Kusus, W G Daniel, and S Achenbach Coronary calcifications in young patients with first, unheralded myocardial infarction: a risk factor matched analysis by electron beam tomography Heart, June 1, 2003; 89(6): 625 - 628. [Abstract] [Full Text] [PDF]
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