Wong Iseng's List: CT Calcium Scoring

• Aetna considers calcium scoring medically necessary for diagnostic cardiac CT angiography to assess whether an adequate image of the coronary arteries can be obtained.

  Aetna considers calcium scoring (e.g., with ultrafast (electron beam) CT, spiral (helical) CT, and multislice CT) experimental and investigational for all other indications because the definitive value of calcium scoring for assessing coronary heart disease risk has not been established in the peer-reviewed published medical literature.

• Research has indicated that EBCT is highly sensitive in detecting coronary artery calcification in comparison to other types of CT.  Moreover, various studies have shown a strong correlation between EBCT calcium scores and quantities of atherosclerotic plaque.  However, there is skepticism about the relationship between EBCT calcium scores and the likelihood of coronary events because of the following factors:

  • Calcium does not collect exclusively at sites with severe stenosis 
  • EBCT calcium scores do not identify the location of specific vulnerable lesions
  • Substantial non-calcified plaque is frequently present in the absence of coronary artery calcification

  • There are no proven relationships between coronary artery calcification and the probability of plaque rupture.
• An assessment of the literature on calcium scoring by the German Agency for Health Technology Assessment (DAHTA, 2006) concluded that measuring coronary calcium is a "promising" tool for risk stratification, but that many questions remain unanswered about the targeted use in medical practice, including which patient groups should be screened,  which calcium score threshold should be applied, and which scoring method should be used. 

1 more annotation...

• Guidelines written in 2000 do not recommend calcium scans for healthy people or those with symptoms of heart disease.¹ This is because calcium scans are relatively new and it is not clear what the test results mean in terms of your risk for a heart attack or other heart problems. Since then, there have been studies suggesting that calcium scans may be useful for detecting early signs of fatty plaque buildup in women with risk factors who have no symptoms of heart disease. In addition, calcium scans are not always covered by insurance. Despite this, an estimated 300,000 calcium scans are performed annually in the US.²

• Most authorities say no. More research is  needed to learn whether a high calcium score  adds significantly to the information provided  by much l ess expensive, better-studied risk  indicators. And even if calcium scores add  significantly to the risk profile, scientists  will have to determine if this information  leads to effective treatments and a better  outcome. The large government Multi-Ethnic  Study of Atherosclerosis is already under way,  but it's not expected to answer these questions  until around 2010.

   

  It may not be wise for you to schedule your  own scan, but should your doctor order an EBCT  for you? More research is needed to answer  this question, too. At present, though, the  test is not likely to help low-risk individuals  who would probably have low scores and are  likely to stay healthy in any case. At the  other extreme, high-risk individuals should  receive treatment regardless of their calcium  scores, so an EBCT is unlikely to help them.  In the middle, however, are some folks with  uncertain risk. An EBCT might help doctors  decide how aggressively to treat them, particularly  if stress testing is inconclusive.

   

  EBCT is a work in progress. It's exciting  progress, and it's likely to help improve the  understanding and treatment of coronary artery  disease. But it's also an example of a recurring  dilemma in modern medicine: Technology has  arrived before doctors have learned how best  to use it.

• Heart scans may show that you have a higher risk of having a heart attack or other problems before you have any obvious symptoms of heart disease. Heart scans aren't for everyone, though. While some walk-in medical facilities advertise that you can walk in for a quick check of your coronary arteries, you should be cautious of these approaches.  

   

   Routine use of heart scans on people who don't have any symptoms of heart disease is not recommended by the American Heart Association or the American College of Cardiology.

• Certain medical facilities and walk-in centers may advertise heart scans as a quick, easy way to measure your risk of a heart attack. These advertisements often target people who worry that they might have a particular disease even if they seem healthy and have no known risk factors. Facilities that promote heart scans for the general public don't require a referral from a doctor. You can walk in off the street and get the scan. However, these scans might not be covered by your insurance.  

   

   If you decide to have a heart scan, it may be best to have it done through your primary doctor, since he or she already knows your other risk factors for a heart attack. If you choose a walk-in scan, be sure to take a copy of the results to your own doctor for follow-up. He or she can help you decide what steps you may need to take to improve your heart health and prevent a heart attack.

• Some researchers think the amount of calcium in plaques can be used to calculate a score that, when combined with other health information, helps determine your risk of coronary artery disease or heart attack.  

   

   But the use of heart scans has been controversial. Heart scans may not be useful for you if, based on your family history and risk factors, you fall into either a low- or high-risk category for having a heart attack. The American College of Cardiology and the American Heart Association have created guidelines to determine if a heart scan may be useful in deciding whether you need to take action to prevent a heart attack within three to five years.