Tag Archives: coronary calcium san

What is the Significance of a Borderline Stress Test and What Is The Value of a Coronary Calcium Score after a Stress Test?

A reader asks me the following question:

I’m 35 years old male and was positive for myocardial ischemia during stress test. The cardiologist said that my result was borderline. I’m not sure what does he meant by “borderline”. Also does it help if I do CAC score since my stress test already came out with positive MI?

Good questions.

First off, to understand what any stress test means we have to know the pre-test probability of disease. For example, in 35 year old males without chest pain the likelihood of any significantly blocked coronary artery is very low. This means that the vast majority of positive or borderline tests in this group are false positives, meaning the test is abnormal but there is no disease.

Even if we add exertional chest pain into the mix the probability of a tightly blocked coronary in a 35 year year old is incredibly low (but there are some congenital coronary anomalies that occur.)

The accuracy of stress tests varies depending on the type. The standard treadmill stress test with ECG monitoring is about 70% sensitive  and 70% specific. Adding on a nuclear imaging component improves the sensitivity (it makes it more likely we will pick up a blockage if it is present) to about 85% however, in the real world, the specificity (chance of a false positive) is still quite high. Accuracy varies a lot depending on how good the study is and how good the reader is.

Borderline for either the stress ECG the stress nuclear (or stress echo) means that the test wasn’t clearly abnormal but it wasn’t clearly normal. It is in a grey zone of uncertainty.

Given your low pre-test probability of disease it is highly likely your “borderline” test result is a false positive. Whether anything else needs to be done at this point depends on many factors (some from the stress test)  but most importantly, the nature of the symptoms that prompted the investigation in the first place.

If there are no symptoms and  you went for more than 9 minutes on the treadmill likely nothing needs to be done.

Would a coronary calcium scan add anything?

A very high score (>let’s say 100 for age 35) would raise substantial concerns that you have a coronary blockage.

A zero score would be expected in your age group and probably wouldn’t change recommendations .

A score of 1 up to let’s say 100  means you have a built up a lot more plaque than normal and should look at aggressive modification of risk factors but likely wouldn’t change other recommendations.

So the CAC might be helpful but most likely it would be a zero and not helpful.

The Widowmaker Documentary: A Need For Heroes and Villains Detracts From The Truth

The documentary, The Widowmaker (available on Netflix streaming)  should definitely be watched by everyone.

It presents some great information on dying suddenly from heart attacks in an entertaining way.

It makes two important points: coronary stents don’t prevent heart attacks and coronary scans can identify advanced coronary artery disease before heart attacks happen.

I am in total agreement with these two points and have made them several times in previous posts (here and here).

The film is a work of advocacy, however, and twists the truth to prove its underlying theory: that greedy doctors and hospitals are choosing to “push” expensive coronary stents that do no good until you are having a heart attack. Also, that doctors and hospitals are also somehow suppressing the use of coronary calcium scans, which could prevent millions of heart attacks and deaths.

Creating black and white heroes and villains in documentaries makes for riveting entertainment, but often at the cost of sacrificing the truth.

Let’s look at the  villains that The Widowmaker presents.

First up is Julio Palmatz. Dr. Palmatz is a vascular radiologist who invented, along with Dr. Shatz, one of the three primary stents that ultimately gained widespread clinical usage. The Widowmaker implies that Palmatz was THE stent developer, and follows Julio as he revisits the garage in Texas where he developed prototypes for the slotted tube stent.

At this point in the movie, it would be understandable if you thought Julio was going to be one of the heroes. He seems very personable as he describes the inspiration for his stent design and points out the area in the garage where his work bench stood.

However, the documentary wants, ultimately, to portray Palmatz as greedy, unconcerned about patient welfare, and in the pocket of wealthy investors.

He has done well financially because the patent on his coronary stent was eventually sold to Johnson and Johnson for millions (and he is interviewed on the grounds of his Napa Valley vineyard).

A recent scholarly analysis of the process of the development of stents differs with this portrayal of Palmatz:

“We found that the first coronary artery stents emerged from three teams: Julio Palmaz and Richard Schatz, Cesare Gianturco and Gary Roubin, and Ulrich Sigwart. First, these individual physician-inventors saw the need for coronary artery stents in their clinical practice. In response, they developed prototypes with the support of academic medical centers leading to early validation studies. Larger companies entered afterwards with engineering support. Patents became paramount once the technology diffused. The case of coronary stents suggests that innovation policy should focus on supporting early physician-inventors at academic centers.”

Although stents ultimately have become over-utilized, they represent a tremendous invention and contribution to cardiac care.

In the setting of acute heart attacks, stents are clearly life saving and thousands of patients have had their clinical angina or claudication greatly relieved when stents are utilized appropriately for blocked coronary and peripheral arteries.

Consequently, Palmatz and many of the other interventional cardiologists who developed and performed early studies on coronary stents are widely considered heroes by the vast majority of knowledgeable cardiologists.

There is no evidence that they have colluded with industry to inappropriately promote stents or to suppress utilization of methods for early diagnosis and prevention of coronary artery disease.

The documentary then switches to characterizing the world of cardiology after stents were approved by the FDA in the early 90s.

There clearly was (and is) an irrational exuberance about stents and some of this sprang from excellent reimbursement for doing the procedures.

The focus moves to Mt. Sinai Hospital in Manhattan, and arguably the busiest interventional cardiologist in the world, Samir Sharmin.

The movie implies that Mt. Sinai was going broke until it began performing lots of catheterization and stent procedures. Sharmin who does over 1500 interventions per year and apparently earns over 3 million dollars per year is interviewed and filmed performing a stent procedure.

The average viewer likely gathers from the context of the interview with Sharmin, that he is only doing these procedures to make money.

At various points during the movie, Dr. Steven Nissen, past president of the American College of Cardiology, is interviewed and referred to as “America’s top cardiologist.”

In my opinion, Nissen has been an outstanding, independent voice of reason in the world of cardiology. During the interview, he makes the very valid points that coronary calcium scans have not been embraced for routine usage because there are no outcomes data.

At one point he says, “I don’t like medical cults” in reference to those who support more widespread coronary calcium scans.

The movie leaves the uninformed viewer thinking that Nissen is part of a cabal blocking coronary calcium scans, perhaps due to his connections with industry or an inappropriate resentment of the “calcium club” pushing the scans.

Nothing could be further from the truth. I think Nissen is one of the few prominent cardiologists who are not subject to major bias of one type or another and I strongly respect his opinions.

The movie also attempts to portray the editor of Circulation, a major cardiology journal supported by the American Heart Association as inappropriately withdrawing a paper that would have endorsed coronary calcium scanning. It’s not possible to really tell what the truth is about this withdrawal, but this is a very minor episode in the history of coronary calcium scanning.

Ultimately, The Widowmaker fails its audience in presenting the truth because it desperately wants to convince us that there is a connection between the promotion of coronary stents and the failure of coronary calcium scans to be accepted by guidelines and covered by insurance.

There is no such connection. Many interventional cardiologists are enthusiastic promoters of prevention and aggressive use of coronary calcium scans. I have seen no evidence of greedy interventionists trying to  suppress coronary scans.

In Part II of this analysis, I will take a look at the “heroes” of The Widowmaker, the inventors and promoters of coronary calcium scans, and we will see if they are truly heroic.