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.

10 thoughts on “What is the Significance of a Borderline Stress Test and What Is The Value of a Coronary Calcium Score after a Stress Test?”

  1. “ Big Pharma “ has thousands of brilliant doctors of medicine , biochemistry, chemistry and many other disciplines who are competing fiercely for the next breakthrough.

  2. Stress test. Timely for me. There was a question about Blood pressure spiking during work/exercise, so I went for it. Last week.
    There were several seemingly incongruous outcomes.
    I reached nearly 180 beats per minute and my blood pressure reached only 160/95. Yet I’m 74.
    I was told I’m clear on ischemia/heart disease. Yet I tallied more than 1,500 on my coronary artery calcium score a few years ago.
    The technician fearfully stopped the test because of an “arrhythmia” which the electrophysiologist later identified as a slight lag in one of the bundle branches (Left? Right?) when I reached that highest beat count. “Normal”. Well, normal enough, I guess?
    How does one rationalize such mixed signals?

    (BTW, notice I avoided acronyms? They’re a bane. Your man who asked the question might well be confusing myocardial ischemia with myocardial infarction. Rather different!
    Oh, and I’d already discounted Gundry and Esselstyn.)

    1. Not uncommon to have very high coronary calcium scan (>1000 or even 2000) with absolutely no ischemia and no significantly blocked (>70%) coronary arteries.
      arrhythmia-sounds more like aberrant conduction than a true “arrhythmia” . At high heart rates it is not uncommon to see one of the electrical pathways to the ventricles start to fail, so-called rate related bundle branch block. Usually not a sign of a problem.
      Acronyms-are everywhere in charts these days. MS to cardiologist is mitral stenosis to neurologist multiple sclerosis or mental status. I’m pretty sure the reader meant MI for myocardial ischemia but that is totally different from infarction.

  3. I’m with you on Dr. Gundry Doc. The price of the supplements are absolutely ridiculous, not to mention useless.

    Wish there was some cancer info on your site–never ?

    Best in health.

  4. I don’t remember how I found your blog but I find it very informative, helpful and humorous. I am familiar with Gundry’s book, and I do feel it is good to have a healthy dose of skepticism. As a person interested in nutrition and health in general, I do read quite a bit and I come across so many claims that can be very unhealthy or just plain absurd. Sometimes there is an element of truth; it is just important not to swallow everything one reads.

  5. Comment re high calcium scan most interesting – three years ago my daughters’s partner died suddenly from a MI, so wife and daughter organised a heart review, including a calcium scan, for me. Despite a good treadmill stress test the 700 calcium score result was heralded as a harbinger of imminent doom – nothing was mentioned about the possibility of no ishaemia and no blocked arteries.

    As there were no clinical signs, I chose not to have any further investigations, but the high calcium score did play on my mind.

    So statins, weight loss and exercise a focus, as well as enjoying a loving family. And now a more positive outlook knowing there is a possibility that my arteries may not be blocked,so focus and effort on heart health are a very good risk management strategy.

    1. High CAC scores for age should not be viewed as the equivalent of “imminent doom” but as an early warning indicator. A strong motivator to get risk factors under control. Most high CAC scores will not need stents or CABG, just aggressive risk factor modification.

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