Science behind Coronary calcium score.

1. What does coronary calcium
score mean?
Dr. Jayanth H. K. MD.
Department of Radiology
Augusta University.

3. How to calculate cardiovascular risk?
• Do you know your own CV risk? If you do not
go to this site below to calculate.
• http://cvdrisk.nhlbi.nih.gov/
• Framingham CV risk calculator uses age,
gender, total cholesterol, HDL cholesterol,
smoking history, systolic BP and if on
medications for hypertension.

4. What is the science behind coronary
artery calcium (CAC)?
• CAC is pathognomonic for coronary artery
atherosclerosis.
• Multiple studies have validated the risk of CV
event increases linearly with high CAC scores.
• CAC scoring is the most powerful predictor of
subclinical atherosclerosis and it is underused
clinically.

5. Who should get coronary calcium
score?
• Guidelines for coronary calcium scoring by
2010 ACCF task force.
• Intermediate cardiovascular risk and
asymptomatic adults- Class IIA.
• Low to intermediate risk and asymptomatic
adults-Class- IIB.
• Low risk and asymptomatic-class III.
• Asymptomatic adults with diabetes, 40 years
of age and older- Class IIA.

6. History of looking for CAC.
• Chest radiographs
• Fluoroscopy
• Cardiac catheterization
• EBCT
• MDCT

7. Background
• MI as you all know is a silent killer.
• 50% or more of these occur in individuals who
have no clue they are at risk of sudden cardiac
event
• CAC score gives added benefit to traditional
CV risk calculators

8. Procedure
• Noninvasive
• Scan time 5-15 seconds
• No contrast
• Score is calculated on a workstation with
software

9. Coronary Calcium Score
• 0 none
• 1-99 mild
• 100-400 moderate
• >400 severe
• CAC score correlates linearly with risk of CV
events and obstructive CAD

10. http://www.mesa-
nhlbi.org/calcium/input.aspx
• Input your age, select your gender and
race/ethnicity, input (optionally) your
observed calcium score and click “Calculate”
• This will convert the raw CAC score into a
relative risk percentile
• No Indian race but chinese is there?

11. What does CAC score “0” mean?
• One may still have noncalcified atherosclerotic
plaque
• Multiple studies have shown only a 0.11 %
annual event rate and 1.1% 10 year risk in
asymptomatic patients with 0 CAC scores.

12. Correlation with obstructive disease
and symptomatic patients
• CAC presence indicates coronary
atherosclerosis.
• Amount of CAC only weakly correlates with
degree of luminal narrowing
• Likelihood of obstructive CAD certainly
increases with increasing CAC scores

13. CAC score relative risks from MESA
study
Hazard ratio
• 0 reference
• 1-100 3.61
• 101-300 7.73
• >300 9.67
• Similar prognostic value of CAC scoring has
been shown to be excellent in multiple large
studies.

14. Advantages
• Easily to do and fairly highly reproducible
• Identify at CV risk individuals earlier
• If CAC present patient may be more compliant
with statins
• Identify low risk patient who doesn’t need a
statin
• Cost effective

15. Disadvantages
• Radiation
• Cost
• More testing

16. Radiation dose
• About 1mSv.
• Background per year 3 mSv.
• Mammogram 0.6 mSv.
• CXR 0.04- 0.06 mSv.
• Head CT 1-2 mSv.
• Chest CT 5-7mSv.
• Coronary catheterisation 3-5 mSv

17. Comparison to other biomarkers
• CAC scoring is superior to HS-CRP in predicting
cardiac events
• CAC was more predictive of coronary disease
than was carotid IMT

18. Conclusion
• CAC scoring is a well validated risk assessment
tool that represents a major advance in
screening for CAD
• The evidence is sound and physicians must be
made aware on the ways to incorporate this
screening tool into clinical practice
• More research is needed on CAC progression
and regression using various treatments for
CAD

19. Case 1

22. Impression
•
1. There is calcified coronary plaque. Total calcium score = 235. The
highest density of these calcifications are at the bifurcation of the
left main into LAD and circumflex coronary artery.
•
2. Based on the MESA study, the calcium score is 67 percentile for age
and gender.
•
3. The 5-year risk of cardiac events is estimated to be 78 % based on
this calcium score.
•
4. Recommendations: Follow up with primary care provider. Primary
prevention for atherosclerotic cardiovascular disease as indicated by
clinical measures.
• 5. Subsequent stress echocardiogram showed no functional stenosis.

23. • No data available to get repeat CAC scores
after starting treatment

24. References
• 1. Detrano R, Guerci AD, Carr JJ et-al. Coronary
calcium as a predictor of coronary events in
four racial or ethnic groups. N. Engl. J. Med.
2008;358 (13): 1336-45.
• 2. http://cvdrisk.nhlbi.nih.gov/
• 3. 2010 ACCF/AHA Guideline for Assessment
of Cardiovascular Risk in Asymptomatic
Adults.

25. • 4. Agatston AS, Janowitz WR, Hildner FJ et-al.
Quantification of coronary artery calcium
using ultrafast computed tomography. J. Am.
Coll. Cardiol. 1990;15 (4): 827-32.
• 5. Problem solving in Cardiovascular imaging
by Suhny Abbara and Sanjeva P.Kalva.