Coronary Calcium Score Azza Farag, MD ... - HeartMirror.com

Vol. 4, No. 2, 2010
Sep 2010: 157-169
Mini-Reviews
162
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3. Coronary Calcium Score
Azza Farag, MD
Abbreviations and Acronyms
EBCT : Electron Beam Computed Tomography
MDCT : Multidetector Computed Tomography
Coronary artery disease (CAD) is currently, and will
remain for the foreseeable future, the leading cause of
death and disability worldwide. Although effective plans
and tools are available for treating and delaying CAD
progression, treatments are underutilized because at risk
individuals are not easily identified. To date, in excess of
300 risk factors for CAD have been identified; however,
most of these are not independent of each other and the
number of truly independent risk factors remains small (1).
Coronary Calcium Score:
It is generally accepted that the presence of coronary
calcium correlates directly with coronary atherosclerotic
plaque burden and its detection is an established technique
for cardiovascular risk assessment (2). Its presence per
se as detected by electron beam computed tomography
(EBCT) or multidetector computed tomography (MDCT)
is significantly associated with incident cardiovascular
disease events independent of the traditional risk factors
such as blood pressure, plasma glucose level and cholesterol
levels (3, 4). But does the amount of this calcium could
independently predict adverse cardiac events, is still yet
not clear.
Calcium accumulates in the coronary arteries in an
age-related manner, and the accumulation appears to be
exponential because calcium continuously deposited in
pre-existing lesion; thus all scores must be adjusted for age
as well as for sex. Modification of the Framingham Risk
Chart variable (chronologic age) by a non-chronometric
variable (biologic age) which is the degree of calcium in
the coronary tree is a debatable issue. However, the concept
allows for a re-definition of conceived risk and might serve
for treatment decisions in primary prevention in subjects
with intermediate risk. The more the calcium becomes
apparent, the older is the coronary lesion in a given patients
and the higher is his subsequent risk (5).
It is important to report that coronary calcium scoring
examination does not define the location or severity of any
particular lesion and it is not substitute for the physiological
stress testing or angiography. Individuals with calcium
score over 10, have coronary heart disease and should
receive treatment to reduce the LDL cholesterol to less than
100 mg% as specified in the ATP III guidelines (6). Repeat
scans are suggested every one or two years to monitor
treatment response. Patients with score over 400 should be
considered for further evaluation to rule out an obstructive
lesion with an exercise or pharmacologic stress test.
These patients are at increased risk for the development of
symptomatic cardiac disease (4.8% per year). Individuals
with symptomatic angina and calcium score >400 have an
extremely high (~15% per year) cardiac event rate (2).
Extracoronary Calcification:
It is well established that atherosclerotic vascular
disease is a diffuse process, thus explaining the association
between coronary and extra-coronary atherosclerosis (7).
Recently, few studies involve extracoronary cardiac
calcification mainly the aortic valve, mitral annulus and
thoracic aorta in the risk profile of patients with suspected
coronary artery disease (7-10). The presence of aortic
valve calcium has been shown to be an independent
predictor of advanced coronary artery disease (7) as well
as carotid stenosis (11) reflecting the atherosclerotic
burden rather than just a degenerative change (12). The
prevalence of three-vessel obstructive coronary artery
disease is approaching 50% in patients with mitral annular
calcification (13).
Although, presence and severity of calcification in the
coronaries has been clearly established as an indicator for
an adverse cardiovascular outcome, the prognostic value of
extracoronary cardiac calcification remained not entirely
clear. It is imperative that the independent prognostic value
of these markers for future events of coronary as well as
non-coronary vascular tree (stroke, peripheral vascular
disease) needs to be asserted (14).
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