Coronary Artery CalciumVimal Ramjee, MD FACC

The Chattanooga Heart Institute

I have no conflicts of interest to disclose.

Disclosures

Recognize the utility of coronary artery calcium scoring in CV risk stratification

Understand the diagnostic modality of CACS and how results affect patients

Implement appropriate diagnostic and therapeutic steps with CACS results

Objectives

I. CAD and calcific plaquing

II. CV risk reclassification

III. Coronary artery calcium score

IV. Therapeutic implications

Outline

CAD and Calcific Plaquing

• CHD remains the leading cause of death worldwide

• CHD accounts for 1 out of 3 deaths in US adults > 35 years

• 41% increase in CV related deaths since 1990

Total CV Death Rate per 100,000

CDC, 2013-2015.

Murabito, Circulation.

CAD: Diagnosis often comes too late

High Prevalence of Subclinical Plaque

Fuster & Sanz, JACC.

CAD and Calcific Plaquing

Sandfort, Circulation.

Cardiovascular Risk Stratification

• Global risk factor scores address only conventional factors Age, diabetes, elevated LDL, low HDL, HTN, tobacco use,

family history

• CACS demonstrates a very high NRI when compared to other risk markers

• High NRI - % patients with FRS estimate that were correctly reclassified by CACS:

52 to 66% in intermediate risk group

34 to 36% in high risk group

12 to 15% in low risk group

Hecht, JACC.

CACS Adds Value Regardless of Other Risk Factors

Cardiovascular Risk Stratification

Hecht, JACC.

Cardiovascular Risk Stratification

Hecht, JACC.

Budoff, JACC. Time to Follow-up (Years)

0 (n=11,044)

1-10 (n=3,567)

11-100 (n=5,032)

101-299 (n=2,616)

300-399 (n=561)

400-699 (n=955)

700-999 (n=514)

1,000+ (n=964)

2=1363, p<0.0001 for variable overall and for each category subset.

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0.0 2.0 4.0 6.0 8.0 10.0 12.0

0.70

0.75

0.80

0.85

0.90

0.95

1.00

CACS Strongly Associated with CV Death

• Asymptomatic adults with intermediate risk (10-20% 10 year risk) –

Class IIA, LOE B

• Asymptomatic adults with low to intermediate risk (6-10% 10 year

risk) – Class IIB, LOE B

• Asymptomatic adults with diabetes – Class IIA, LOE B

• Low risk (< 6% 10 year risk) should not undergo CAC measurement –

Class III, LOE B

ACCF/AHA Guidelines, 2010 & 2013

Indications for CAC Assessment

Coronary Artery Calcium Scan

• Ambulatory non-contrast CT scan with limited FOV

• 3 to 5 second breath hold

• Low radiation exposure

< 1 mSv (<< 1 mSv with newer systems)

Nearly equal to radiation from a mammogram

Approximate radiation from living in a big city x 3 months

• Costs less than most tests that are covered ($59 out of pocket)

• Immediate printed results given to patient

• Printed report tells referring provider what percentile via MESA

Blaha, JACC.

Coronary Artery Calcium Scan

0 = No identifiable calcium

1-99 = Mild disease

100-399 = Moderate disease

≥ 400 = Severe disease

• Calcium = presence of atherosclerosis, but atherosclerotic lesions

do not always contain calcium

• Calcium may occur early in life, and not necessarily in functionally

significant lesions (i.e. significant stenosis)

• CAC of 0 = very protective = < 1-2% chance of CV event next 10 yrs

• CAC > 0 – CAD is unequivocally present

• Even ‘low’ score of 1-10, confers a significant risk of CV events

• High (>100) and very high (>400) are proportionally associated with

more risk

Coronary Artery Calcium Scan

Berman, JACC.

CAC Score and MPI Result

Hecht, JACC.

Therapeutic Implications

• CACS > 0 confers greater risk of CV events, therefore ideal to initiate:

Aspirin 81mg PO daily

Statin therapy – *Irrespective of lipid level

• CAC > 100 confers high risk of CV events

Careful clinical assessment

Consider stress testing (? Functional stenosis)

• If initial CACS = 0, consider repeat scan no earlier than 5 years

Thank You

• Email: vramjee@chattanoogaheart.com

• Phone: (973) 960 - 7188

Don’t hesitate to reach out!

Likelihood of CAD based on Risk Factor

DATA TAKEN FROM “THE DAWN OF A NEW ERA -

NON-INVASIVE CORONARY IMAGING” R. ERBEL HERZ 1996; 21, 75-77

DIAGNOSTIC SENSITIVITY

0% 20% 45% 60% 70% 90%

INVASIVE

MODALITIES

STRESS ECG $300

STRESS ECHO $900

PET SCANNING $2200

Coronary Calcium with CT $295

NON-INVASIVE

MODALITIES

INTRAVASCULAR ULTRASOUND $3,000

CORONARY ANGIOGRAPHY $5,000

STRESS THALLIUM $1600

$59