Saturday, August 8, 2020

Management of MI can be similar to stroke: Use CT angiogram. Don't depend only on STE on ECG for reperfusion?

This new article from the VERDICT trial may help to change the MI paradigm to OMI-NOMI.

Coronary CT Angiography in Patients With Non-ST-Segment Elevation Acute Coronary Syndrome

https://www.onlinejacc.org/content/75/5/453.abstract

They found that CT Coronary angiography could be done rapidly and may be used
to exclude coronary artery stenosis of at least 50% in patients with NSTEACS.

Scans could be done within 2 hours.  They were read by experts, but perhaps it won't be long until more radiologists/cardiologists (ED physicians?) become good at reading these.

Maybe some day soon....





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MY Comment by KEN GRAUER, MD (8/8/2020):
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Interesting article by Linde et al (JACC 75[5] – Feb, 2020) — the central illustration and abstract of which are shown and linked above. In the interest of generating discussion — I’ll put for the following initial impressions I had on this abstract.
  • It would be nice indeed to simplify (and expedite) evaluation of patients with NSTE-ACS (Non-ST Elevation Acute Coronary Syndrome). This study suggests that it is possible with high accuracy (91% Negative Predictive Value) to exclude a ≥50% coronary stenosis by means of CTA (Computed Tomography Angiography). And indeed — it would be helpful in patients with NSTE-ACS to know that emergent cath is not needed because CTA was done in the ED and came back negative.
  • According to the central illustration (above) — 88% (666/758 patients) of those with either a non-diagnostic or positive CTA result had significant coronary disease (presumably treated by reperfusion).
  • Average time in this study to complete CTA evaluation was ~2.5 hours after the diagnosis of NSTE-ACS was made (1.8-4.2 hour range). This means the decision to perform CTA will entail some delay (probably at least 1-2 hours ...) in performing emergency cath if CTA results come back positive or equivocal. This needs to be factored into the decision-making process. I’d argue that IF clinical history + the initial ECG suggest OMI (despite lack of ST elevation) — that time should not be lost ordering CTA, and then having to wait those couple of hours in the hope of getting a negative CTA result that would provide high likelihood ( = 91% NPV) that there is no acute occlusion (albeit 91% is not 100%!).
  • That said — CTA could prove very helpful in that group of NSTE-ACS patients in whom the initial ECG did not show a clear picture of OMI. That’s a group of patients who you (working in the ED) didn’t want to press for emergent cath — and in whom obtaining a negative CTA result would support your decision!
  • And if it turned out that CTA surprised you with a positive result on your patient whose initial ED ECG did not suggest OMI — then you now will have evidence to help convince a cardiologist who otherwise might not have wanted to do emergency cath. This point is especially important for the NSTE-ACS patient who does not show OMI on initial ECG — but who has persistent chest pain and/or positive troponin — since a positive CTA result should remove any resistance you might have encountered from your interventionalist to perform emergency cath.
  • That said — Realize that according to the Central Illustration (above) — that only ~25% of patients (ie, 265/1023) in this study will have a negative CTA result. Not mentioned in the abstract (but alluded to in the audio summary by Dr. Fuster) — was a large number of patients with NSTE-ACS who were excluded from this study for a variety of reasons.

BOTTOM LINE: As per Dr. Smith — this study presents a potentially important addition in the ongoing shift toward an OMI-NOMI Paradigm (as per our July 31, 2020 post).
  • My concern would be that CTA not become an overused modality that is substituted for sound clinical judgement. IF despite lack of ST elevation, the initial ECG clearly shows evidence of OMI — then — Do not delay by doing CTA. Instead — Activate the cath lab.
  • At the present time — I envision the greatest benefit of CTA in the ED will be in the group of NSTE-ACS patients in whom their initial ECG does not suggest OMI, and you eitheri) Don’t want to press for emergency cath, and are looking for additional support of that decision; orii) You didn’t want to press for emergency cath — but the surprise result of CTA is positive — so you now know that emergent cath is indicated; oriii) You did want emergent cath done all along despite no OMI on initial ECG — but you need evidence to convince your interventionalist to do the cath.
  • Reasons why you may have wanted emergent cath done all along despite no OMI on initial ECG include: i) A nondiagnostic but nevertheless suspicious ECG; ii) The patient has persistent cardiac-sounding chest pain; iii) Positive troponin; and/oriv) You need cath to make a definitive diagnosis of your patient’s symptoms.


3 comments:

  1. very exciting. My friend, Mikey Mastalski first brought this article to my attention a few hours ago, in the context of a young woman (40's),out of hosp cardiac arrest, "non-diagnostic" initial post ROSC ecg, but CTA suggestive of OMI. taken then to PCI, finding a severe LAD lesion.
    when i first heard about CCTA as a part of the decision process, a few years ago, i, like Jerry Hoffman,was extremely skeptical.
    when i asked Steve Smith about 8 months ago(after hearing a pod by i think it was a chief of rads at Mass General) about this new-fangled CTA for coronaries, he was very positive about it.
    It seems using it appropriately may be very helpful. Using it nandy-pandy can be dangerous.
    i am concerned about the radiation, the cost, the danger of finding "disease" (will this lead to unnecessary caths?), and does a less than 50% lesion mean "good to go"? aren't many ,if not most OMI's formed in vessels with less than 50% disease? it's still unclear to me what this all means, ultimately.

    thanks, gentlemen.
    tom

    ReplyDelete
    Replies
    1. Thanks for your comment Tom! You mention Jerry Hoffman — and I remember well (many years ago) hearing Jerry talk often about CTA use (and misuse) in primary care. It all depends on HOW and WHY you use the test. In primary care (my specialty) — I thought this test had risk of gross overuse. There might be selective cases (a very small percentage of the general population) for whom doing CTA screening might assist in risk assessment — but in general, it just isn’t needed (other far easier and less expensive ways to screen) — and risk of false positives because of elevated CTA scores taken out of context run risk of leading to excessive “extra testing” (procedures, not all of which are noninvasive).

      BUT — In an ED setting, as per the above algorithm from the VERDICT Trial — there IS exciting potential for use. As per My Comment above — there still are cautions. I believe finding optimal emergency use of CTA is still in the “moving target” phase — but if used appropriately, this test could be a winner. Discussion from others on this subject is WELCOME! — :)

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    2. 2 different uses:
      1) rule out signif CAD in chest pain workup. Extremely helpful in patients who are neither very low nor very high risk. Yes, most MI are in < 50% lesions but only because there are millions of 50% lesions in the population. tighter stenoses are much more likely to fissure an thrombose. Also, coronary intervention is not the only intervention. If you see disease, patient can be started on statin, maybe also aspirin, can get closer followup. Most recent large randomized trial over 4000 patients with stable angina showed more early downstream procedures, but at 5 years number of procedures was the same and death + MI was 2.2% vs. 3.8%.
      2) worried about OMI: this is the new indication that I wrote about in the blog. Looks like you used it to some benefit?

      Delete

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