Add Boston Globe to the list of heart scan blunders
Posted Sep 22 2008 10:15am
Yet another piece of mass media misinformation hit the airwaves today. This time it's not from the New York Times or the LA Times, both of which have previously mangled the issues surrounding heart scans. This time it's from the Boston Globe.
In an article titled What is a calcium scan for heart disease, and who should undergo the test?, the report states:
". . . calcium scans may not be a good idea, or prove terribly useful, for most people. For one thing, the scans expose a patient to significant radiation - equivalent to roughly 50 chest X-rays" said Dr. Warren Manning, chief of noninvasive cardiac imaging at Beth Israel Deaconess Medical Center."
As many before him, Dr. Manning is confusing two tests: CT coronary angiography and CT heart scanning. Perhaps we can't blame him: This technology has had its weakest following in the northeast, for reasons not entirely clear to me. (In fact, Track Your Plaque followers have had the greatest struggle obtaining heart scans in that part of the country.) Nonetheless, you'd think he'd have his simple facts straight before talking to the press. Unfortunately, hospital public relations departments will usually just grab whoever they can willing to talk to the press--regardless of their expertise or lack of.
The story goes on to say:
. . ." it's not clear what to do with the results from a calcium scan. If you have diabetes, high cholesterol, high blood pressure, or a family history of heart disease, you already know - or should know - that you are at increased risk of heart problems and should lower these risk factors. So, a calcium scan provides little additional information," Manning said.
"Moreover, even a high score doesn't necessarily mean that the calcified plaque in your arteries is obstructing blood flow, said Dr. Adolph Hutter, a cardiologist at Massachusetts General Hospital."
"The vast majority of people with high calcium tests don't have obstructions and they do fine long-term. So you'd have to test lots and lots of people to prevent one heart attack or sudden death," said Manning.
And if you get a low calcium score, a sign of little or no calcification of plaques, that's not very useful, either, because it could be wrong, or it could be right but lull you into believing you do not have to exercise and watch your diet, cholesterol, and blood pressure levels. "You can still be at risk even if your calcium test is negative," Hutter said.
It is truly shocking how little many (not all, thank goodness) of my colleagues really know about 1) heart scans, 2) coronary disease prevention, and 3) prevention in general. These same "experts" likely advocate high-dose statin drugs and low-fat diets for people at risk. They likely refer patients to the American Heart Association for diet advice and themselves obtain a lot of information from the pharmaceutical industry. The notion of identification, tracking, and purposeful reversal of coronary plaque is entirely foreign to this bunch.
"The vast majority of people with high calcium tests don't have obstructions and they do fine long-term. So you'd have to test lots and lots of people to prevent one heart attack or sudden death." Well, take a look at a graph from a database of 25,000 people undergoing heart scans then observed for several years afterwards:
You can see quite clearly from the curves that heart scan scores very clearly predict your future (if no preventive action is taken). The higher the score, the greater the likelihood of heart attack and death. How much clearer can it get?
The most recent addition to this literature is the PREDICT study which concluded:
Hazard ratios relative to CACS [coronary artery calcium scores] in the range 0-10 Agatston units (AU) were: CACS 11-100 AU, 5.4 (P = 0.02); 101-400 AU 10.5 (P = 0.001); 401-1000 AU, 11.9 (P = 0.001), and >1000 AU, 19.8 (P
In other words, a heart scan score of >1000 is associated with a 20-fold increased risk of cardiovascular events (without preventive efforts). That kind of predictive power and quantitative confidence simply cannot be squeezed out of blood pressure and cholesterol values.
How about the 2008 University of California-Irvine study from the New England Journal of Medicine (do the northeast docs even pay attention to something that is published in their own neighborhood?) that reported:
There were 162 coronary events, of which 89 were major events (myocardial infarction or death from coronary heart disease). In comparison with participants with no coronary calcium, the adjusted risk of a coronary event was increased by a factor of 7.73 among participants with coronary calcium scores between 101 and 300 and by a factor of 9.67 among participants with scores above 300 (P
<0.001 for both comparisons). Among the four racial and ethnic groups, a doubling of the calcium score increased the risk of a major coronary event by 15 to 35% and the risk of any coronary event by 18 to 39%.
"In these men, coronary calcium was associated with an 11.8-fold increased risk for incident coronary heart disease (CHD) (p = 0.002) in a Cox model controlling for the Framingham risk score. Among those with coronary artery calcification, the risk of coronary events increased incrementally across tertiles of coronary calcium severity (hazard ratio 4.3 per tertile)."
Calcium score provided additional information even after factoring in the Framingham risk score.
That's just a sample of the studies. There are a number more.
Add to these conversations the fact that, unlike reducing blood pressure or LDL cholesterol, the heart scan score is a quantification of the disease itself. It can also be tracked over time to gauge the success or failure of prevention efforts. To believe that blood pressure reduction or LDL cholesterol reduction is sufficient to eliminate risk is something only a fool would believe.
Contary to the above statements, the data are clear:
--The higher the heart scan score, the greater the risk. This has been demonstrated beyond any shadow of a doubt in at least a dozen published studies. In fact, heart scan scores outshine lipid/cholesterol values several-fold.
--A person with a zero score has a nearly zero risk for cardiovascular events over a 5-year timeline.
--Heart scans are the only quantitative test available of coronary atherosclerotic plaque. This means that they can be repeated to gauge progression or regression. Cholesterol does not do that. Stress tests do not do that.
--Heart scans are not the same as CT coronary angiography.
--The lack of "need" for a procedure does not equate to the absence of disease.
The power of heart scans is that they can uncover evidence for coronary atherosclerotic plaque 10 years before a cardiac disaster strikes. Witness Tim Russert's heart scan score of 210 in 1998 at age 48. 10 years later, you know what happened.
Beware the camipaign of misinformation and ignorance that continues that is hell-bent on maintaining the procedural status quo or locking us into a "drugs for all" mentality.