FAST CT SCAN OF THE HEART (EBCT)
W. G. Franklin, M.D.
- A fast CT scan of the heart is a 45 second non-invasive method of detecting coronary artery calcification (hardening of the arteries, arteriosclerosis)
- The technical name is electron beam computed tomography (EBCT)
- Another name is SMART SCORE or CARDIAC CALCIUM SCORE
- The test is 99% accurate after the age of 30 in detecting arteriosclerosis of the coronary arteries
- Comparison to a PPD skin test for TB is useful :
- Like a PPD, its greatest value is in separating people into those with disease (or exposure) from those without disease
- Those with disease, arteriosclerosis, merit yearly surveillance with a stress test and preventive medication
- A negative test is 99% accurate in determining who does not need a stress test, preventive aspirin, etc.
- A fast CT scan does not determine the degree of blockage across the width of a coronary artery
- It does, however, determine the extent of the arterial surface (relatively speaking) that is diseased
- Since heart attacks can occur with blockages that extend across the artery from 10% or less through 100%, the extent of disease (the higher score) does correlate with the risk of heart attack
- On the other hand, a stress test (treadmill, nuclear Thallium, or stress echo) detects a problem when there is a 70% or greater obstruction
- These stress tests do not detect a problem with a blockage extending less than 70% of the way across the artery
- Actually, stress tests vary from 70 to 95% in accuracy of detecting even a 70% obstruction
- For unknown reasons, stress tests are less accurate in women.
- Virginia Hospital Center, Arlington (Formerly Arlington Hospital) was the first in northern Virginia to offer the fast CT scan
- In 1991, of approximately 1100 tests performed, 500 were negative
- It detects the number one killer, arteriosclerosis, in its earliest stages
- This permits aggressive treatment with multiple medications that can reduce the risk of heart attack to 1%
- It confirms the knowledge that not everyone is at risk
- Not everyone with a cholesterol level above 200 needs medication
- Since 30% of heart attacks occur in people with a cholesterol level below 180, it is more accurate as a predictor than blood cholesterol levels
- It is quick (45 seconds or less), non invasive (painless), and costs less than some stress tests (approximately $450)
- At present, fast CT scans are covered by most insurance companies
- Repeating the test after 2 to 5 years will allow for assessment of progression or regression of disease, response to treatment program
- As with stress tests, it is recommended for those with risk factors such as:
- Family history of arteriosclerosis (heart attack, angina, bypass surgery, stroke, angioplasty, etc), hypertension, high cholesterol, low HDL (high density lipoprotein), diabetes, smoking
- Strong consideration should be given to patients on hemodialysis, those with aortic aneurysms, peripheral arteriosclerosis, aortic valve thickening on echocardiography and aortic arch calcification on routine chest x-ray
- Check with your physician regarding advisability of having the test, availability in your community
- If necessary call the Radiology Department at Virginia Hospital Center (703-558-5000), or call HeartCare of Virginia at 703-527-1400
- in the near future, it is likely that MRI techniques will allow sufficient visualization of obstructive plaques to distinguish non-invasively between 50% and 70% (hemodynamically significant) blockages
The fast CT scan is revolutionary because:
Literature Cited
Hecht, Harvey, et al. EBCT and National Cholesterol guidelines in asymptomatic women. JACC 37(6); May 2001: 1506-1511.
Grundy, Scott; Coronary calcium as a risk factor: role in global risk assessment. JACC 37(6); May 2001: 1512-1514.
Callister, Tracy et al. Effect of HMG-CoA reductase inhibitors on CAD as assessed by EBCT, NEJM 339(27), December 31, 1998; 1972-1977.
Iribarren, Carlos, et al. Calcification of the aortic arch: risk factors and association with CHD, stroke, and peripheral vascular disease. JAMA, July 7, 2000. 283(21):2810-2814.