Charles was visibly confused.
He'd gotten his CT heart scan after hearing one of the local scan center's ads on the radio. His score 2773 , obviously in the 99th percentile for any age.
"Do you think the score means anything? My primary doctor said that it was meaningless because it was all in the deep wall of the artery. He said that it has nothing to do with risk for heart attack. As long as I feel good, he says don't do anything."
What exactly did his doctor mean, in the "deep wall of the artery"?
What the doctor is referring to is the fact that some people with a long history (many years) of diabetes or kidney failure (also for many years) tend to develop calcium deposits in the media, or muscular layer of arteries. The media is the tissue thin layer just below the intima, the most inner layer of arteries that we usually associate with atherosclerotic plaque and the layer that is most prone to calcium accumulation that we score on heart scans.
Aging, generally into your late 70s, 80s, and onwards, also increases the likelihood of medial calcification. Lastly, longstanding deficiency of vitamin D encourages medial calcification.
Is there any way to distinguish intimal vs medial calcification on a heart scan? No, there is not. Having read many thousands of CT heart scans, I can tell you that there is no practical way in 2007 to tell the difference.
Then how did this doctor "know" that Charles' calcium was "deep walled" or medial? Simple: He didn't. This was yet another example of ignorance based on old thinking. Unfortunately, he did Charles a serious disservice by dismissing his heart scan score that predicted a 25% per year risk for heart attack.
Interestingly, whether calcium is intimal as in atherosclerotic plaque, or medial, both are strongly associated with risk for heart attack. In other words, if calcium is confined to the intima, heart disease risk is present. If calcium is limited to the media, risk is still present.
In all practicality, the only difference we make of the intima vs. media argument (that is, when the distinction has been made by some other means like intracoronary ultrasound, the test that is truly necessary to distinguish the two patterns) is that medial calcification may be more powerfully related to vitamin D deficiency. Thus, someone with heavy medial calcification may require closer attention to maintaining a perfect year-round blood level of 25-OH-vitamin D3. But that's the only practical difference.