Against Stress Testing

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Nurses Edition Commentary

Kathy Garvin, RN and Lisa Chavez, RN
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Tim V. -

This is really well done. Thanks, Justin.

Steve D. -

I completely agree with all that and would probably not want a stress test myself. That said, it is standard of care in the US so very hard to not do.

Justin M., M.D. -

I agree entirely. Stress testing is used routinely, and you don't want to be the sole doctor who chooses not to use it, especially when we know that there will be occasional misses. I would be careful about the term standard of care. From my conversations, I believe there are a few physician groups in the US that don't routinely use stress testing, so there are definitely groups of similar prudent physicians who would consider not ordering a stress test acceptable care, but I am not a legal expert. Rather than trying to change individual practice, I think it is much better to present the data to your entire group, and make a formal protocol on what to do, which then essentially sets the standard of care for your group. Although I think you could eliminate stress testing all together, it probably makes sense to start with the low hanging fruit - such as patients with low HEART scores. I never order stress tests, but things are definitely different in Canada and New Zealand where I work. I have never worked in the United States. But I think we are all very similar, in that we just want to provide the very best care for our patients, and I think stress testing is probably hurting a lot of patients, so it is worth the effort to (slowly) make this change.

donald b. -

Hello,
Thanks for the great segment - really helpful. It wasn't clear to me if Dr. Morgenstern was referring to only low-risk patients (assuming using heart score to do initial risk stratification) that should not have stress tests?
Would intermediate-risk patients also fall into the group that doesn't need stress testing? Currently, we are ruling out our intermediate-risk patients in an obs unit with a longer rule out (up to 12 hours) and then arranging for cards follow up (and usually stress testing). Do the referenced studies include these non-low risk patients?
We are in a rural, semi-austere environment where follow up is a challenge so this would be a major change to our practice and a great benefit to our patients if we didn't actually need to schedule stress tests - any additional information on this would be super-helpful.
Thank you very much
Don Bader
Fort Defiance, AZ

Justin M., M.D. -

Hi Don. Thanks for the question.
Unfortunately, the answer is a little complex, because there isn't a single definitive study you can point to for "the answer". However, when I am making this argument, I am talking about stress testing in ALL patients. I have not sent a single patient for a stress test in probably 7 years.
Many of the observational studies looking at stress testing were limited to lower risk patients. However, there is pretty good evidence that even the patients we don't consider low risk won't benefit from stress testing. For example, a study by Napoli in 2014 looked at chest pain patients admitted to an observation unit, and out of 3500 patients, not a single one had and MI during the follow up.
I will also note - the 2/1000 miss rate that I quote is for all comers, so that does include the intermediate risk group you are talking about (but they may be washed out by lower risk patients).
Even without specific evidence in the moderate risk group, the rest of the logic still holds. What are you going to do with the results? If the patient had negative troponins, we have clear evidence that they don't benefit from stenting / invasive management. And the stress test still has horrible sensitivity and specificity for coronary artery disease. So it is an inaccurate test that doesn't lead to any change in management. So your pretest doesn't really matter - the test can't possibly help.
I couldn't cover all the evidence in a short EM:RAP piece. If you are interested in digging a little deeper into the evidence, I have a lot of references in my blog posts on the topic (there are 6 parts):
https://first10em.com/stress-test-evidence-intro/
https://first10em.com/mi-miss-rate/
https://first10em.com/defining-cardiovascular-outcomes/
https://first10em.com/stress-test-accuracy/
https://first10em.com/revascularization-evidence/
https://first10em.com/stress-tests-conclusion/

All the best
Justin

Ian L., Dr -

In the Pope JH study NEJM 2000
894 patients had MI diagnosed after work up
972 had unstable angina after work up .
11 patients refused admission despite medical advice .
The missed rate of MI was 19/889 .
For unstable angina the miss rate was 22/966 .
After adjusting for age sex risk factors and Comorbidities the ratio of deaths in those discharged to those admitted was 1.9 :1.0
It was May 1993 - Plus 7 months when CK -MB was the biomarker.

Mortality in those hospitalised for MI was 9.7% for those discharged 10.5 % (2)
With Unstable Angina Mortality in the discharged was 5.0 % ( 1) those admitted to hospital 2.1 %
So in this study misses with adjustment for various factors resulted in greater deaths than finds - ratio 1.9 : 1.0 as at 1993 but in a small sample .
Re -"never doing a stress test" .
A 60 year old diabetic male with a blood pressure of 160 systolic non smoking and total cholesterol of 7 wants to get fitter and undergo an exercise programme at a gym .
His 10 year risk of a cardiovascular event in 10 years is 25-29% by the Australian and New Zealand Cardiovascular Risk Calculatons .
He ought to have a stress test and calcium score plus or minus a CCTA in my view .

Justin M., M.D. -

Thanks for the comment
1) With regards to the Pope study, I think you have to be very careful when considering the denominator. Although it is true that they missed 2% of MI patients, that only represents 0.2% of all chest pain patients. Seeing as we don't know which patients are which, for the patient in front of you - who is an undifferentiated chest pain patient - the risk of a missed MI is 0.2%.
In terms of the mortality risk, it's hard to take the adjustments too seriously. The actual, unadjusted mortality was identical between the group of patients that went home with missed MIs and the patients diagnosed on their first visit. There was no difference. Which is an important point I didn't bring up in the podcast: we didn't hurt these patients at all by missing them. Their outcomes were exactly the same.

2) With regards to your example - I still don't see any role for stress testing.
First of all, what are you going to do with the result? This patient clearly needs risk factor modification. We don't need a stress test to tell us that. The patient should definitely be encourage to exercise, although he probably needs to be counselled about how to do that safely if he hasn't exercised in years. There is no data, as far as I know, that suggests a stress test can predict who is safe to start an exercise program. This patient (with negative troponins and a normal ECG) also clearly doesn't need an angiogram or revascularization. So how is the stress test going to change your management?
Even if you thought getting a formal diagnosis of CAD was really important, the best data we have says that an exercise stress test has a sensitivity less than 50%. If you really think the information is important, are you willing to use such an inaccurate test?
With regards to CCTA - there have been a few requests for a follow up already. I'm just starting my full literature review, so I'll get back to you. (However, asking the same question - how is this going to change management - hints that CCTA is also going to have very limited utility.)
All the best
Justin

Dallas Holladay, DO -

Nice piece, I tend to agree. We can get stress tests from the ED. I rarely do it but I get a number of patients signed out to me waiting for stress test results. I've not seen cards take any positice stress tests for cath. They typically get a CT coronary study and discharge with ASA, cholesterol and possibly BP meds.

Justin M., M.D. -

Thanks for the comment.
I think you make a really important point - one of the best signs that we are using a poor test is the frequency with which we ignore the results. We know the white blood cell count is useless for abdominal pain or cough, because whenever if disagrees with our initial impression (which is the majority of the time I think), we just ignore it. Stress testing is the same in some settings. That being said, I get a lot more worried in places where the stress test results are never ignored, because the result is a lot of necessary invasive procedures.
Cheers
Justin

James P. -

In my place we have no support for chest pain and it's a binary discharge home or ED obs for stress test in AM. Moderate or high risk end up getting a stress because we have nothing else to offer.

I just did this 3 days ago and the patient's stress (cardiac PET perfusion) was positive and he just got a CABG. He realistically could have been called "low risk" because he was 70 without risk factors. I called him "moderate risk" because his chest pain was concerning enough to make him a HEART score of 4 which convinced me to stress him. Should we send these home? Is this CABG potentially not beneficial based on the evidence?

Sorry I originally posted this on the main EMRAP page. I am glad you are here answering questions. Very interesting piece and I believe that in general stress testing doesn't help but it takes some of the burden off of us sending moderate to high risk patients home even if it doesn't actually provide survival benefit.

Justin M., M.D. -

Thanks for the comment
It obviously impossible to know whether CABG helped the specific patient you saw. In general, it is a little hard to discuss the benefits of CABG, because all the studies of CABG vs medical management took place in the 1970s. And there was a clear mortality benefit of CABG over medical management. However, even thought most of these patients were called "angina", the diagnosis what completely different back then. These were very high risk patients with classic stories for ACS. My guess is that the vast majority of these patients would have had positive troponins. You can get a sense of how high risk these patients are by looking at the meta-analysis (Yusuf 1994) - the medical management group had a 5 year mortality of 15%! Compare that to the modern trials I presented, in which people with negative ED workups had essentially a 0% risk of MI and death at 1 year, and I think you can tell we are talking about completely different populations.
Since the 70s, all the studies have basically compared CABG to PCI. There is a little controversy in the cardiology world, but in general it is thought that PCI is noninferior to CABG. Therefore, if we know that PCI doesn't help patients with negative troponins, I think it is safe to say that is mostly true for CABG as well. (Although there may be occasional patients with classic angina, uncontrolled by medical management, with sigificant LAD or triple vessel disease that won't have positive trops but might benefit from CABG - we don't really have the evidence to say.)
So where does that get us? I think it means that the vast majority of patients with negative troponins and normal ECGs should be sent home with no further testing. There will be an occasional patient with an absolutely classic story who you might decide to send for further investigation. However, I am also hesitant to use a stress test in the high risk patients, because it will miss too many people. (Exercise stress tests have a sensitivity of less than 50% and even nuclear studies only have sensitivities close to 80%. If you really think the patient is high risk, are you comfortable using a test that will miss 1 in 2 to 1 in 5 patients?) I think the best approach is to identify the really high risk patients clinically, and get cardiology to assess them, knowing that for the vast majority of people with negative troponins, there is no role for interventional management, so your only option is good medical management.
Unfortunately, getting rid of the stress test takes away our safety net - the problem is, I think when you look closely at that net, it is full of massive holes. We feel better that it is there, but it isn't actually helping our patients at all. In fact, overall, I think it probably hurts them, because of the massive numbers of both false positives and false negatives.
All the best
Justin

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