Last review and update: January 21, 2020.
Introduction: “You make an assumption we can do something about it (about a non-zero CAC score).”
The interviewer (Christopher):
(What about) the coronary artery calcium score (CAC)?
Dr. Malcolm Kendrick:
Well, maybe. We don’t know.
You’re again making an assumption that we pick that up and we can do something about it (about a CAC score > 0) .
Malcolm Kendrick on preventive screening for cancer and cardiovascular disease.
In a recent podcast, Dr. Malcolm Kendrick, a thinker, criticized the idea of “preventive screening” for cancer and cardiovascular disease. Malcolm was skeptical also about the coronary artery calcium scan (CAC), currently popular in the grassroots health community.
Below, there are some of Malcolm Kendrick’s ideas about the utility and consequences of “preventive screening”. Anybody who has Common Sense arrives at similar conclusions.
Preventive medicine vs “preventive screening”.
Dr. Malcolm Kendrick:
The preventive medicine (is about) the basic concept (that) it’s better to stop people getting unwell in the first place. (Which is) true. But that’s not the same as screening… Screening is picking up disease early. (While) preventing or delaying… is …about making people generally healthy. But we’ve mixed up the two things and we’re saying that screening is prevention. It’s not.
On preventive screening for breast cancer.
Dr. Malcolm Kendrick:
They did a study in Australia where they looked at women who died in accidents and other things, and examined the breast tissue. (They) found that 40% of women had what you could diagnose as breast cancer. And yet, (only) about 4% of women get breast cancer.
What were these other things? Were they all going to kill them? No. Will they ever grow? Maybe. Will they ever recede? We don’t know. We don’t know what the natural progression of most of these things are going to be. And yet, we’re going to say to all of them that we have found breast cancer.
This thing, ductal carcinoma in situ, you can find it in millions of women. Was it ever going to turn into something nasty that was going to kill them? Well, in a vast majority of cases, no. You can’t then say to the woman: “Oh, well, don’t worry, we may find cancer, but it’s probably all right.” You’re then forced to remove the breast or something. That’s a huge amount of harm that you’re going to cause to people which you probably didn’t need to.
On cardiovascular screening.
Dr. Malcolm Kendrick:
They did a survey of all cardiovascular screening programs that we carried out over the years (throughout the world) to find out what the benefit has been. You know what the finding was? The total benefit in reducing cardiovascular disease from all these screening programs was zero. They said 1 was the average risk. The confidence interval was 0.99 to 1.01. That may not mean anything to you. What that means is that it was bang on zero with no possibilities that it was wrong. So these screening programs didn’t do anything at all.
Now, we have the health authorities in the UK saying you must do more cardiovascular screening. Based on what? You have no evidence that they work. In fact, all the evidence says they don’t work.
The interviewer (Christopher):
(What about) the coronary calcium score (CAC)?
Dr. Malcolm Kendrick:
Well, maybe. We don’t know. You’re again making an assumption that we pick that up and we can do something about it.
Cardiologist Bernard Lown and his research on invasive coronary procedures (bypass, angioplasty).
Dr. Malcolm Kendrick:
I’d advise you to read Bernard Lown who I think is still alive. He must be about 100 by now. He is a cardiologist who works in the States for a long time. Brilliant man. Brilliant, brilliant man. My hero.
(Bernard Lown) tried to look at coronary artery bypass grafting because he wasn’t sure it was (adding) benefits. (There were) problems with the angiograms (that were) causing people to have stroke and things. He tried to do a study on whether they worked or not. It (invasive coronary procedures) was a big operation. It was making millions. Everyone was having coronary artery bypass.
They have this thing where they do an angiogram which shows up your arteries in die. Your major artery is called the left anterior descending artery because it sends blood to your left ventricle which is the one that does the biggest pumping. And if it had an obstruction of something like 50% or whatever it was, they used to call that the widow maker, can you imagine?
Dr. Malcolm Kendrick: “Obviously, the moment someone said you’ve got a widow maker, you need a coronary artery bypass.”
Dr. Malcolm Kendrick:
Obviously, the moment someone said you’ve got a widow maker, you need a coronary artery bypass.
Bernard Lown eventually managed to do a study where they did a non-invasive medical treatment to one half of the participants and an invasive coronary intervention (a bypass?) to the other half.
Dr. Malcolm Kendrick:
His (Bernard Lown’s) findings were that the coronary artery bypass graft provided no benefits overall.
He (Bernard Lown) couldn’t publish the paper for years…
It seemed like it must be an obviously beneficial thing to do. You’ve got a blocked artery. We must put extra veins around it and get the blood supply. Well, this doesn’t work like that. Because the heart produces what is called collateral circulation, whereby if you block one artery, there are other little arteries to take over the blood supply. In fact, that’s more likely to save you because if that (large) artery fully blocks then these little extra arteries will keep you alive and you won’t die. Whereas if you bypass it and if you then have a heart attack… So, it’s actually bad for you.
The operation itself had a 4% mortality rate and doing the angiogram can cause strokes.
Analysis.
There is a place for invasive coronary procedures, like bypass or angioplasty. However, the challenge is to figure out if this approach is the most appropriate and if the medical practitioners who advise it are not influenced by other factors.
A non-zero CAC score in a person already on a healthy diet.
The non-invasive medical treatment of coronary artery calcification is also a challenge. In particular, it is the case if a non-zero coronary artery calcium (CAC) score is discovered in a generally healthy asymptomatic person who already has a healthy diet and lifestyle. What else can this person do? What else other than anxiety a high CAC score can bring?
Once calcification is there, it tends to progress.
The annoying thing is that once calcification is there, it tends to progress. In patients who take statins, calcification may progress faster than in those who don’t take statins. However, in those who don’t take statins, CAC scores also increase with time.
From Dykun et al., 2016 (1):
In unadjusted regression analysis, taking a statin
was associated with 39% higher progression in CAC+1
(Table 1). This relationship was slightly attenuated
after adjustment for cardiovascular risk factors but
remained statistically significant, with approximately
31% higher progression of CAC+1, attributable to
statin intake.
Conclusions: Do you need “to know your score”?
So, should you do a CAC scan? Do you need “to know your score”? What can you do about it if it is not zero?
A Physiologically Literate approach would be to focus on the analysis of your metabolic markers with a goal to find out the factors that may be responsible for arterial calcification.
What causes arterial calcification? Why some have it and others don’t? How to prevent and how to reverse arterial calcification? Answers to these questions exist. It is one of the subjects of our current research.
Additional info:
The link to the podcast’s audio at 01:49:56, where the discussion about preventive medicine and preventive screening starts:
https://overcast.fm/+CJZFbaHrk/1:49:56
Selected References:
1. Dykun et al, 2016, Statin Medication Enhances Progression of Coronary Artery Calcification: The Heinz Nixdorf Recall Study. Journal of the American College of Cardiology, Volume 68, Issue 19, 8 November 2016, Pages 2123-2125.
I thought I’d heard of some CAC scores lowering following dietary intervention. False?
There are reports of CAC score lowering. However, just a dietary intervention, notably, a low carb diet, may not be enough.
We have a program where we optimize biomarkers of our clients with a specific goal of preventing and/or reversing arterial calcification.