MI after passed stress test

Discussion in 'Emergency Medicine' started by cbrons, Aug 2, 2015.

  1. cbrons

    cbrons Ratatoskr! *Roar*
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    One of my attendings told me that a stress test is only good for the exact day it was performed. This week I saw a 70-something y/o female with a massive inferior wall MI almost exactly 48 hours after she passed a stress test.

    I was wondering if you have had similar situations before. I was pretty shocked.
     
  2. Birdstrike

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    You shouldn't be shocked. This is where you need to understand test sensitivity (and specificity). Stress tests are not 100% sensitive, in fact, the actual number is significantly less than 100%. Therefore there will absolutely be false negatives.

    Therefore, if a test isn't 100% perfect, nor 100% accurate detecting a disease you will have a certain number of people that absolutely 100% have the disease in question, yet have an absolutely "normal" test, and therefore they're absolutely 100% ready to keel over and die in front of you, despite everyone, their cardiologist with "normal" stress test in hand included, telling you it's not so. This is why artificial intelligence and Google-algorithm robot-protocols will not replace you or I in any of our lifetimes.

    Moral of the story: Being a doctor is hard. No test is 100% accurate and always hedge your bets.
     
    #2 Birdstrike, Aug 2, 2015
    Last edited: Aug 2, 2015
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  3. Daiphon

    Daiphon Semper Ubi Sub Ubi
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    Stress tests predict fixed obstructive lesions... NOT spontaneous thrombi.

    Even with a neg stress, if they have the story then they get the workup.
     
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  4. Gastrapathy

    Gastrapathy no longer apathetic
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    This is a pathophysiology question. AMI is plaque rupture. Stress tests are designed to assess for fixed obstruction. And of course they aren't perfect.
     
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  5. link2swim06

    Physician 10+ Year Member

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    You should NOT be shocked. Let me make an analogy. Would you be shocked if a patient with a high pre-test probability and a negative d-dimer had a PE?

    If the patient has a high pre-test probability they need a cath not a stress test. A negative stress doesn't really provide much useful info in this population. Maybe they have clean coronaries, maybe they have triple vessel disease.

    A stress test is good for a single isolated fixed lesion. If they have multiple lesions they may not be detectable on the stress test since it's basically balanced ischemia throughout the heart. I have seen this twice during one month of being on cards.



    A recent stress definitely doesn't rule out ACS. If anything it's evidence that the ordering doctor probably thought the pt might being having angina that probably hasn't been evaluated by cath yet.
     
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  6. Arcan57

    Arcan57 Junior Member
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    You're overvaluing caths. There are less invasive ways of finding out if someone needs aggressive risk factor modification and stenting fixed obstructions doesn't prevent MIs.
     
  7. TimesNewRoman

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    Stress tests are TERRIBLE tests. Not just that, but as addressed above, stresses are to assess inducible ischemia, not to assess the risk of a small lesion rupturing.

    Listen to David Newman's Smart EM podcast. It's a little out of date, but really is worth listening to.
     
  8. EM4life

    EM4life attending
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    You should absolutely not be surprised, it happens frequently. The only thing that maybe somewhat reassuring is that from a medical-legal standpoint, you are more protected but you should not be falsely reassured by a neg stress test or even a recent cath showing only "mild" disease.
     
  9. link2swim06

    Physician 10+ Year Member

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    No but a recent negative stress test on a triple vessel disease patient presenting with unstable angina isn't very useful in my short experience dealing with this.
     
  10. WilcoWorld

    WilcoWorld Senior Member
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    You can't admit and cath everyone. (Well, you could, but I wouldn't recommend it.)

    I learned from "expert opinion" (my malpractice-wary attendings in residency) that a stress test expires after 1 year. I've never found evidence to support this.

    On the other hand, I learned from my patients that a stress test expires as soon as they stop the ECG tracing.

    So, how do I reconcile these "facts", and see chest pain patients without going crazy? I divide them into 4 levels:

    1 - If you know it's not ACS - Don't worry, don't test. (e.g.: the pain started in the back and moved to the front and they have zoster in a left-sided T6 distribution).

    2 - If I know it's ACS - Ignore last month's stress test. Hell, ignore your troponin. Admit them. (e.g.: the 72 yo had CP while mowing the lawn, sat down to have a cigarette and was surprised when that didn't make it better, then became nauseated and almost passed out, at which point his brother brought him to the ED and now he has flipped t waves in contiguous leads).

    3 - I could be ACS, but something else is much more likely - Test for that something else, if it's positive - treat, if it's negative, see #4.

    4 - If you don't think it's ACS, but you don't want to loose a law suit - Do whatever is the culture for low-but-not-no-risk chest pain at your shop. At my shop that means observing those with stress tests over 1 year old.
     
    #10 WilcoWorld, Aug 2, 2015
    Last edited: Aug 2, 2015
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  11. Arcan57

    Arcan57 Junior Member
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    Other than convincing them to be compliant with their regimen and making sure they haven't had an MI, there isn't much that's useful in the above scenario. While we pretend that we influence the outcome, in a world without medico legal risk we'd accept that somethings we just can't change.
     
  12. alpinism

    alpinism Give Em' the Jet Fuel
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    Agreed.

    Most AMIs arise from small unstable plaques (vulnerable plaques with a thin fibrous cap) not the large stable ones causing exertional ischemia that stress tests are designed to detect.

    The best thing you can do for these patients is to recommend starting a Mediterranean diet, quitting smoking, and exercising every day.

    [Edit] Here's the SMART EM link: http://emcrit.org/chestpain/
     
  13. la gringa

    la gringa Senior Member
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    I have seen STEMI 2 weeks after neg stress recently.

    Very recently had neg dimer (ordered by a colleague) with +PE on CT... high risk so i wouldn't have even done the dimer.

    and yes, this is why we aren't replaced by computers yet
     
  14. Angry Birds

    Angry Birds Angry Troll
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    I'd had always been told that stress tests are as good as flipping a coin. Don't know if that's true or not, but I generally don't give too much weight to when they had a stress test. Only reason I even ask is because I know the hospitalist will ask when I call to admit the patient.
     

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