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 Coronary
artery disease (CAD) and its manifestations is the leading cause of
death and disability in the United States in both men and women. Patients
are usually first diagnosed with CAD when they develop symptoms, display an
abnormal response to stress testing, or undergo coronary angiography.
Atherosclerosis is the only process which results in the deposition of
calcium within the walls of arteries. Calcification of the arterial bed is
NOT a degenerative process and is NOT related to the aging process itself.
Indeed, this is a very active metabolic process, in many ways similar to
bone ossification. Early on in the atherosclerotic process, calcium deposits
are very small and difficult to detect with conventional x-ray imaging, and
this had created a significant impediment to the use of coronary calcium as
a marker of CAD. Over the past few years CT scanning has advanced to the
point that detection of even miniscule calcium deposits can be accomplished
quite easily. CT scanning, therefore, affords an opportunity to detect
coronary calcium, and by inference, coronary atherosclerosis, early - before
patients develop clinical manifestations of coronary disease. Recent
advances in Helical CT have allowed coronary artery scoring to be performed
on general-purpose CT scanners.
The presence of ANY coronary calcium signifies that underlying CAD is
present. The "calcium score" (an amalgamation of total size and density of
the calcific deposits found throughout the coronary tree) provides a
quantitative evaluation of extent of plaque burden. In general, the higher
the "score" the larger the plaque burden and the higher the risk of
subsequent cardiac events in both symptomatic and asymptomatic patients.
Although the relationship between the calcium score and severity of luminal
narrowing has been found to be nonlinear, data regarding specific thresholds
exist to help utilize the score in a clinically meaningful context.
A limitation of coronary calcium scanning is that although calcium
deposition occurs relatively early in the atherosclerotic process, plaque
material initially is not calcified and only approximately 20% of overall
plaque volume is calcified. Therefore very minimal atherosclerotic changes
may be missed by this technique. It is important to keep this point in mind
- and the results of the scan should be viewed as only one, albeit powerful,
component in the assessment and management of a particular patient. While
risk assessment has mainly been studied utilizing electron beam CT, Helical
CT has shown good correlation and the following statistics assume similar
numerical applications which may not apply.
A calcium score >400 implies the presence of extensive CAD, with a high
likelihood (>90%) of at least one significantly obstructed vessel (>70%
stenosis). Patients with scores >400, would be considered at high risk for
subsequent development of symptomatic cardiac disease.
A score between 10 and 400 indicates a moderate plaque burden, and is
associated with an intermediate, although significant risk of future cardiac
events, especially when scores are >100. The odds ratio of developing
symptomatic cardiovascular disease has been reported to be as high as 25:1
in patients with scores >100 and 35:1 in those with scores >160. The risk
stratification capability of coronary calcium scoring is especially
significant when compared to the predictive powers of traditional risk
factors in foretelling the development of symptomatic coronary disease:
1.8:1 for total cholesterol >240mg/dl; 1.8:1 for HDL<35; 3.6:1 for cigarette
smoking; and 1.2:1 for systolic hypertension.
The clinical significance of a particular score is influenced by the
patient’s age and gender. A score of 150 may be "average" for a 70-year-old
man, but would be considered markedly abnormal for a 40 year old woman. The
correlation between calcium score and plaque burden is identical in men and
women, however, just as clinical manifestations of CAD are delayed in women
as compared to men, so is the development of coronary calcium.
BIBLIOGRAPHY
Arad, Yadon, MD, Spadaro, Louise A., MD, Goodman, Ken, MD, Lledo-Perez,
Alfonso, MD, Sherman, Scott, MD, Lerner, Gail, MS, and Guerci, Alan D., MD.
Predictive value of electron beam computed tomography of the coronary
arteries.
Becker, Christoph R., Kleffel, Timm, Crispin, Alexander, Knez, Andreas,
Young, Jason, Schoepf, U. Joseph, Haberi, Ralph, and Reiser, Maximilian.
2001. Coronary artery calcium measurement: agreement of multirow detector
and electron beam CT. AJR:176, May.
Carr, J. Jeffrey, Crouse, III, John R., Goff, Jr., David C., D’Agostino,
Jr., Ralph B., Peterson, Neil P., Burke, Gregory L. 2000. Evaluation of
subsecond gated helical ct for quantification of coronary artery calcium and
comparison with electron beam ct. AJR:174. April.
DISCLAIMER
While multirow detector subsecond Helical CT has shown excellent correlation
with electron beam CT, the majority of population statistics and
recommendations have utilized EBCT to predict significance of calcium
scores. Therefore, there may be clinically significant discrepancies in
recommendations based upon Helical CT derived data.
Don't
wait until it's too late!
Coronary Artery
Calcium Scoring is a screening procedure that can save your life and it
takes only about 10-15 minutes. There are no needles, dyes or injections
involved.
-
Are you a
male, 40 years or older / or female, 45 years or older?
-
Do you have
a family history of heart disease?
-
Do you have
high cholesterol?
-
Do you
smoke?
-
Do you have
high blood pressure?
-
Are you a
diabetic?
-
Are you
overweight?
-
Do you have
a sedentary "couch potato" lifestyle?
If
you answered YES to any of these questions, then you need to know your
Cardiac Calcium Score.
Call
(864)295-4422
today
to schedule your appointment, or click
here for internet request.
Greenville
Radiology, P.A. 1210 West Faris
Road Greenville, SC
29605 (864)295-4410
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