today we're talking about the calcium scan or calcium score and we're going to cover five
super common myths about the calcium score. let me know how many of these you find surprising,
I'm guessing for most people it's going to be most of them. first of all, what is the calcium scan?
it's basically a CT scan, works by x-rays, you lie down, they slide you into the scanner and it
basically takes an x-ray image of your chest and it can show the calcification in your coronary
arteries, so the arteries feeding blood into your heart muscle. in the end you get a calcium score,
which is basically a quantification of the amount of calcification in your coronaries. it's a quick
test, takes about 10-15 minutes and it costs about 100 bucks ballpark, depending where you go. and
the calcium score can be useful, it can give us an idea of how advanced the plaque in your arteries,
in your coronary arteries is. so the first myth about the calcium scan is "I have a calcium score
of zero so that means I have no plaque". I see even medical doctors sometimes saying this on
social media. that's a big misconception. a calcium score of zero doesn't mean no plaque
because the calcium score doesn't measure plaque per se, it measures calcification, and
calcification happens pretty late in the disease process, in the plaque formation process, so it's
possible for me to have a calcium score of zero and have what's called soft plaque, non-calcified
plaque, and actually in some cases you can have plenty of it. here's a striking example, this
study looked at people who had lots of plaque, the diameter of the coronary artery was reduced by 50
percent or more so they call that obstructive coronary artery disease. out of those people,
14 percent had a calcium score of zero but it varied a lot depending on age, for older people,
70 years old or above, only five percent of people with that level of obstruction had a calcium score
of zero, but for young people, under 40, it was 58 percent, so most young people with obstructive
coronary artery disease, with a lot of plaque, had a calcium score of zero. They concluded
that the diagnostic value of a calcium score of zero was small in younger patients and greater
in older patients. they also followed 24 000 of these people with a lot of plaque for four years
and about 30 percent of the heart attacks or death that happened in that group
happened in people with a calcium score of zero. don't get me wrong, if you have a calcium score
of zero the odds that you have obstructive CAD, obstructive coronary artery disease,
that you have that much plaque, are very low, it's in the single digits, it just doesn't rule
it out because in people who do have substantial amounts of plaque, especially if they're younger,
calcification may not have had time to develop. so a calcium score of zero is good news all
else held equal, it's a marker of lower risk in most cases, it just doesn't guarantee immunity,
doesn't guarantee safety. that's the take-home message. hope that makes sense. also, good to
remember we can have plaque in many other places besides the coronaries. in this study they found
that out of people with a calcium score of zero, 54% had plaque in the legs or in the carotids
leading up to the brain. to put it succinctly, a calcium score of zero is desirable but far
from perfect. so think of calcium as the tip of the iceberg, it's a marker of advanced disease,
if you can see it it's a signal that there is a lot more under the water, if it's not there, if
you can't see it, maybe there's nothing, but there could be, there could even be a substantial amount
and it could even be growing fast, the calcium score can't rule that out, especially at an early
stage. okay, second myth or misconception, a calcium score of zero doesn't even mean that
there's zero calcification, it means no detectable calcification. the scan picks up calcification
above a certain size but not smaller calcium spots. in this study for example they found that
about four percent of people with a calcium score of zero had some calcification that they could see
with more sensitive methods. okay but this is a little academic, is there calcification or not,
even is there plaque or not, at the end of the day what we care about is risk, what's my risk of
having a heart attack or a stroke, etc, right? the rest is kind of details. so let's talk risk. the
third myth is that a calcium score of zero means no risk. I see people saying this all the time,
"I have sky-high LDL-cholesterol or ApoB but my calcium score is zero so I'm completely safe".
that's like saying my glucose is sky-high, I have raging diabetes, but my toes aren't tingling yet,
I still have all 10 toes. that's good to know but it's a very low bar and it doesn't guarantee
long-term health. these authors spell it out: "clinicians should clearly communicate that a
score of zero does not imply that risk of an event is zero (event means heart attack, stroke, etc) or
that the patient has zero atherosclerosis (so zero plaque) and a calcium score of zero may provide a
false sense of security". the key mindset here is time frame. short term versus long term. a calcium
score of zero indicates very low five to ten year risk of an event like a heart attack. about one
percent chance over the next 10 years According to some studies. okay, one percent chance of having
an event like a heart attack over the next 10 years, how relevant is that? depends. if I'm 80
or 90 years old and I have a low risk of a heart attack in the next 10 years, that's good stuff,
but for example, I'm 45, if somebody tells me that my risk over the next 10 years of having a
heart attack is very low, okay... um that's good to know but I wasn't counting on it. I sure hope
not. what I really want to know is the next 30 or 40 years. it's explained here really clearly:
"preventive Cardiology has begun looking ahead to Lifetime risk rather than 10 years for
calcium score and most risk calculators". now, I recently discussed exactly this issue with Dr
Tom Dayspring. Tom is an internal medicine and lipidology specialist and here's what he had to
say: so I think once calcium is there that's one of these big indicators to me you are the person
I'm gonna blow ApoB and try and make it 40. but if you come to me and your ApoB is whatever and you
say but I did a coronary calcium and it's normal I would say okay, so here's the decision to make,
are you worried about what's going to happen to you in the next 10 years or are you worried
what's going to happen to you at ages 70 80 90? because if you are then we're going to start
maybe trying to lower your apob regardless of your calcium score. but if you're just saying,
am I gonna have a heart attack in the next 10 years? and your CAC is zero, I would say no, and
therefore do I want to lower your ApoB? it only depends if you're worried about longer term events
of atherosclerosis, then you're always going to lower ApoB. so you get into that question,
so you know these people go on their ketotic diets and send ApoB through the stratosphere, they go
get a coronary calcium and it's zero and they say God thank God I don't have to do anything,
and you're playing that game again. at what point is that ApoB going to harm you, or is your wishful
thinking gonna come true and it's never going to harm you. and you can play that game in yourself,
you're the only one who can make that decision, no matter what Tom Dayspring tells you or some
other advocate of ApoB is meaningless tells you, you can decide yourself. so the key
takeaway here is that the value of the calcium score hinges heavily on the age of the person.
oftentimes when I see someone on social media saying my cholesterol is Sky High but I have
this calcium score of zero so I'm totally relaxed, and by the way I'm 33 years old,
there's a misunderstanding there in terms of this temporality and the long term. a calcium score of
zero is the norm in young to middle aged people. for example in the cardia study among people 36 to
42 years old, 90 percent had a calcium score of zero and in the Mesa cohort for people a little
older, 45 to 54 years old, 73 percent had a score of zero. so even up to mid 40s mid 50s,
most people have a calcium score of zero. and that's for Western populations, right? where
cardiovascular disease is the number one cause of death and it's incredibly common so it really
drives home this idea that a calcium score of zero is what's expected, it's not a high bar
unless you're significantly older, if you're 70 or 80 or something like that then it starts to be
more reassuring. put in simple terms, a calcium score of zero in a younger individual is normal
and expected but it has a lot more power at an older age. just like fine wine, the value of a
calcium score of zero increases with age. I love a good analogy and that's a pretty good one. okay,
fourth myth or misconception is "I'll just keep an eye on my calcium score and if it shoots up then
I'll make some changes". remember, calcification is a pretty late manifestation, it's a marker of
a pretty Advanced stage of the plaque, so it's not a warning that the disease might progress,
It's a diagnosis that it already has. by then you're basically doing damage control.
yes, there are still several tools to manage risk, to reduce it, to prevent it from rising further,
pharmacological and lifestyle, but the real bang for our buck is in preventing the plaque
from forming in the first place. in other words, plaque calcification is a late event so it does
not accomplish early pre-plaque detection, the goal being to prevent any plaque from
forming in the first place. now, of course the amount of risk that I'm willing to tolerate
is a personal decision, it's for us to decide, for each one of us to decide with our doctors,
just be aware that waiting for the score to go up to then address risk factors is largely missing
the boat, the window of opportunity, so as long as it's an educated decision and people are aware of
all the factors. there are more sensitive Imaging methods that measure soft plaque as well, like
angiography for example, but it is more expensive and more invasive, here's Tom going over it. you
also know Gil, that there is a much more intensive Imaging procedure of the coronary arteries where
you just take a needle and you inject a dye, you don't stick a catheter up in somebody's heart but
you inject a Dye that can show up in an x-ray, and it's called CT angiography and that can show
plaque that is not yet calcified, it might show, God, you got plaque, you got an 80% lesion there
but it's not calcified, maybe you got a lot of smaller lesions that are not calcified but how do
you know they're not going to rupture tomorrow and cause the thrombus that will occlude your artery?
so CTA would be a much better test to do except it's 10 times more expensive, radiation exposure
in the wrong hands can be way more, in the right hands it's not very much at all, so... but it's
super expensive, your insurance company might not even cover a $100, $200 coronary calcium,
they're not going to cover a $1,500 CTA, so there are other issues. if everybody in the world could
go to CTA at a certain age, fine, but that's never going to happen of course. most of the time CTA is
done investigating people with chest pain. okay, Fifth and last myth is that the calcification in
the artery is the cause of risk. calcifications don't cause risk, they're a marker of risk,
they're an indicator of how advanced the disease is. the more plaque someone has and the longer
they've had it the more likely that there's calcification but the calcification itself is
not the problem, in fact it can sometimes be a benefit, calcification is part of the scarring
process of the artery and it can actually make it less likely to rupture and cause an event. in
fact plaque disruption and thrombosis tends not to happen in calcified segments but in adjacent areas
so calcium is not actually the causal mediator, it's not what causes the problem itself. I hope
this isn't too confusing, in general more calcium is a signal of higher risk because
it's a marker of more plaque and more advanced plaque underneath, just like the iceberg image,
but you could have something that raises calcium and doesn't raise risk or even that lowers it,
right? a little odd, a little counterintuitive maybe, but hopefully it makes sense now that we
understand the calcium is just a marker of disease progression. the most poignant example of this are
statins, patients on a Statin sometimes see an increase in their calcium score yet their
risk of an event is going down, that's because statins have a plaque stabilization effect that
can involve calcification. here's Tom Dayspring again explaining this much better than I ever
could. another thing pertaining to calcification that confuses a lot of people is that statins can
increase calcification a little bit, right? indeed there are studies showing that but in all trials
what do statins do? they reduce the incidence of heart attacks. so statins you can make the case
are stabilizing existing plaque, they're scarring it off so calcium appears but that is unlikely to
be a plaque that's going to rupture and induce a clot that's going to send you to the CCU, so never
would you stop a Statin because a coronary calcium score is increasing, you judge Statin efficacy not
by follow-up Imaging but by ApoB, that's what tells you, is the Statin working or not? when
they first came out I had people who would run and get them every year, I didn't advise it, but
cardiologists at that time did. it's a waste of money and time because we know the Statin trials
show especially if your apoB is going down you're going to have less heart attacks regardless of
your calcium score so right now I see people are sort of recommending, well if you get a calcium
score, maybe you should repeat it in anywhere from four to six years because you can maybe,
especially if it was zero to begin with, it's now positive, but even say it was positive but it goes
up astronomically high, is that a worry? maybe that would lead you then to a CTA or other better
evaluation of your coronary tree, but you don't make Statin decisions per se only because of what
might be happening to a coronary calcium score. so bottom line, a calcium score has prognostic value,
it can help to determine what someone's risk level is, and it's especially relevant in three
situations: a young person with a score that is not zero, that's a red flag. an older person with
a score of zero, that's reassuring. and the third case is in borderline situations, maybe someone
who has some risk factors but it's not clear if starting medication is the right move, or the
person would rather not, in those cases a calcium scan can help tip the scales one way or another,
it could be a decent tiebreaker. here's Tom Dayspring again: the guidelines currently suggest
if your LDL-cholesterol is above a certain level or your ApoB is above a certain level you are in
a group that should consider Statin therapy, but if you are totally anti-drug therapy, things that
would twist your arm and say, you better go on a Statin, would be a positive coronary calcium
or the presence of lp(a) or the presence of diabetes, then you always go on a Statin,
so that's how coronary calcium tests can be used. any tests are great tests if you know
how to interpret them and use them and then explain it to the patient what exactly, how
it helps us solve maybe part of the problem, but atherosclerosis is a long-term problem. a great
resource that just came out recently is a one-page primer on the calcium scan, it's Illustrated,
written in a way that anybody can understand and it covers all the basic ideas you need and it's
completely free access so I'll link that in the description below. hope this information helps,
let me know your questions in the comments, take care, I'll catch you next week, bye