Coronary calcium scans: NYT article highlights value and minimizes limitations

Michael Joyce is a writer-producer with and tweets as @mlmjoyce

On Monday, the New York Times “Well” section published this column by Jane Brody:

The Value and Limitations of a Cardiac Calcium Scan

(The headline was later changed to ‘One More Heart Test to Consider: A Calcium Scan’)

Coronary calcium scan promotion from Riverside Heart & Vascular Institute in Chicago

It caught our eye because it’s a screening test for heart disease that we’ve followed for almost a decade. What we’ve mostly run into is news coverage that implies widespread benefits of the test, while neglecting potential harms and very significant limitations. We’ve also found some journalists reporting on their own anecdotal experience with these tests, which has sometimes taken precedence over systematically collected medical evidence in these stories. 

So a headline which promised to clarify both the benefits and limitations of the test gave us some hope. But that was short-lived.

The anecdote

The story opens with an anecdote of Brody’s sexagenarian brother who apparently didn’t follow the most heart-healthy lifestyle despite a family history of premature cardiac death. We’re told that his results were presumably satisfactory, he was quite relieved, and he didn’t use the result to “throw caution to the winds” and misinterpret the result as permission to continue his heart-unhealthy ways.

But are readers to accept this as evidence proving the value of the test? That the test somehow helped her brother? Did it actually give him new, actionable information he didn’t already have from recommended blood tests or from his doctor carefully weighing his risk factors (ie, age, gender, exercise level, tobacco intake, diet, and family history)?

The gist

The article goes on to accurately describe:

  • what the test is (a specialized x-ray “that highlights calcium deposits in the plaque that can line and clog the arteries feeding the heart”) and how it compares to a CT angiogram (a similar test using dye injected by vein)
  • how it forms the basis of a scoring system that suggests levels of low, moderate, and high risk for heart attack (based on increasing calcium visualized in the coronaries)
  • how the scale can help guide doctors in deciding whether or not to prescribe cholesterol lowering drugs (ie. a higher score might sway doctors to prescribe one)

The column states that the test is increasingly popular, the cost has dropped down to nearly $100 in some areas, and it “could be of great value for millions of aging American at risk of life-threatening heart disease.”

The gist is mostly about benefits. Only when we get to the very last paragraph do we get this:

There is still no definitive evidence from randomized controlled clinical trials to show that patients with elevated calcium scores who are treated to lower their risk actually experience a reduced rate of cardiac events. Researchers at Wake Forest School of Medicine have calculated that it would require a costly trial of about 30,000 people deemed to be at low-intermediate risk of a future heart attack to show such benefit.

That’s the real gist addressing the headline. And while we were glad to see it included, why is it relegated to the very end of the story like an afterthought?

Critical points

The US Preventive Services Task Force (USPSTF) has found insufficient evidence (benefits vs. harms) to support CAC testing over traditional risk assessments for cardiovascular disease in adults without heart symptoms. Further, the USPSTF cautions:

Abnormal results may lead to further testing, procedures, and lifelong use of medications without proof of benefit, but with expense and potential side effects for the patient. Psychological harms may result from being reclassified in a higher risk category for CVD events.

[CVD = “cardiovascular disease” events; mainly heart attacks and stroke]

I think including this key information from the USPSTF would have helped readers considerably. And there’s more.

First, is radiation exposure. Although calcium scanning of the heart has improved in this regard, the amount of radiation exposure still needs to be considered and weighed against what’s to be gained from knowing the CAC score. This is becoming more relevant as the cardiology community debates the value of repeated coronary calcium scanning, thereby substantially increasing radiation exposure.

Also, although an elevated CAC score does indicate plaque in the coronary arteries, not all heart attacks come from these calcified plaques. That means a normal or low risk CAC score does not exclude the possibility of a heart attack. This relevant point was raised in the piece and we were glad to see it included.

Two of our physician contributors weigh in

Adam Cifu MD

“I generally find calcium scores unhelpful,” said Adam Cifu, MD, and internist at the University of Chicago. “Often patients don’t need it. Either they are at low risk and the results are meaningless, or they’re at high risk and already maximally risk controlled and the results lead either to to anxiety or false reassurance.”

But Cifu adds that he will rarely order the test in very specific circumstances.

“Usually this is in patients without traditional cardiovascular risk factors. They have normal lipids but a worrisome family history. These then are low-to-moderate risk people in whom a high calcium score would make me more aggressive about modifying their risk factors with something like aspirin or a statin. It may not be an evidence-based approach, as there are no trials to fully support this, but it is reasonable based on previous studies.”

Christopher Labos, MD

Cardiologist Christopher Labos, MD agrees.

“It simply refines risk prediction,” said Labos. “If you had a medium risk patient and weren’t sure about whether you should start a statin or not, the calcium score could help tip the balance. If the calcium score was high that would help justify starting the medication.”

But he raises another point which highlights why Brody’s opening anecdote about her brother isn’t all that helpful.

“One of the main problems with calcium scans is even they’re completely normal, you still need to recommend the healthy lifestyle changes. So you haven’t really gained anything.”

Why this matters

We’ve been critical of the the New York Times “Well” section in the past. And there was plenty of room for improvement in this relatively unfocused piece that ignored key aspects of the debate over coronary calcium.

That missing information is crucial because these scans are being directly marketed to the public. This is worrisome. It means that anyone who is concerned about their heart — for well-considered reasons or not — can waltz in to such a center and walk out with a number they, or the centers providing the test, don’t know what to do with.

As noted above, what happens next runs the gamut from a “negative” test providing false reassurance (or “permission” to continue unhealthy behaviors) … or … a high score dictating a cascade of further tests and/or treatments that carry risks themselves, and that the best available evidence shows will have no impact on outcomes or treatment decisions.

Once again it brings up a very pragmatic piece of advice worth remembering when considering any kind of screening test: What are we actually screening for? And will the information give me and my doctor new information that will help us make changes that are proven to affect outcomes that really matter?

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