vimal ramjee, md facc the chattanooga heart …...vimal ramjee, md facc the chattanooga heart...
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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.
Cu
mu
lati
ve
Su
rviv
al
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
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