Cardiology Corner: High Sensitivity Troponins

From the PDF show notes "You have a patient with possible ACS. The ECG is non-ischemic. The first high sensitivity troponin is in the positive rangeat 16 ng/L. You can call to admit the patient for rule in." Is that perhaps a mistake, as the following example states "You have a patient with possible ACS. The ECG is non-ischemic. The first high sensitivity troponin taken 4 hours after onset of pain is in the gray zone 40 ng/mL." 16 is positive zone in the first example, 40 is gray zone int he second example.

How much troponin elevation from 1st to 2nd draw is considered a positive test?

We have been using the high sensitive troponin assays down under for over 10 years. A few thoughts...

We are at the point that we can measure a circulating level of troponin in just about everybody. It's not like the old days when a measurable troponin was always a concern.

Just about anything that makes the heart "angry" will cause the troponin to go up. You don't need to memorise a list... just know this broad concept.

The reference range for troponin was derived in healthy human volunteers who have been screened out for co-morbid conditions. As such, it is no surprise that when we use it in our typical ED patient population, we see a lot of borderline elevations. This is fine... this is normal... get used to it. Have a plan for dealing with it. Look at their older "baseline" troponin results. Perhaps check a delta value in one or two hours if you are on the fence. Once again, a mildly elevated troponin in a 80 year old with hypertension & mild renal impairment would be considered normal and expected. Don't cause harm by over-diagnosis and treatment. Don't flood your cardiologists and wards with inappropriate admissions.

The cut off of 52 was data snooped and should not be applied to all patients... I would strongly caution blindly adhering to this cut-off. A troponin of 30 in an otherwise healthy younger person with no comorbid illness is a serious red flag.

In summary, the troponin is no longer a "dumb test" where any "positive" result means something. Now more than ever we need to use our brains when interpreting the results.

The one lesion that is critical to exclude is left main coronary artery stenosis which affects 4-6 % of acute coronary syndromes so if a patient is not getting a catheterization a CCTA with the low dose radiations being performed soon could be very important.

Hi All, I recall Amal saying a few years ago that HS-Troponin may create more problems than it solves. I have worked in Australian ED’s for the last 14 years and we have had the HS-Tn for quite a while.

In my view it has become a screening test with poor specificity for the emergency doctor who is trying to find the patient with non- stemi changes and a poor history who may be going to have a major occlusion (The patients mentioned by the defence lawyers). That beast is rare in my experience but cardiac catheterisation is not.

I see this test being done by younger doctors not as a confirmatory test of a clinical suspicion of ACS based on history and ECG findings but done as the gold standard for deciding on who is being admitted as a “NSTEMI”. (Regardless of Hx and ECG)

This is concerning on several levels, first I have never had a Troponin level dictate my management of a STEMI. They go to the cath lab based on history and ECG findings.

As reported in EMA June 19(Abstract 24), the ED population (not the general population), those presenting with something more than a sore toe or cold being tested with HS-Tn even when they have no chest pain is around 13%.
The patient with chest discomfort or chest pain is likely to be higher.

However, we let the troponin dictate our management of this less acute patient with less stringent criteria on history and ECG, than a STEMI. This equals admission and cardiac workup and in my experience once worked up it is a rare cardiologist who does not proceed to cath.

The data from the recent ISCHAEMIA trial and the ORBITA before that would make me wonder if we are doing a service to our patients at all with this test. It is certainly sensitive however, it is not specific when low positive and does not tell anyone who is at risk of a major occlusion. Otherwise, why is almost everyone routinely given a cardiac catheter usually after an inconclusive non-invasive investigation?

Amal, you were correct when you said it would not be the answer to our prayers and more is the pity.

I can't get the EM RAP 2020 June MP3 Files Zip to work. I specifically want to download the "Cardiology Corner: High Sensitivity Troponins" discussion.

Thanks!

Hi Amal, i listened to you talk on this. Had my first day yesterday using them. I thought i ws prepared. I am confused with what to do with the elevated trop at time zero in a patient with low likelihood (trop ordered by pmd or at triage). One was a 55yo man with some neck pain and hx htn normal ekg and his trop at 9 am was 117. The neck pain was mechanical and present for a week (hurt to move). I saw him at 7pm and trop was 104. one hour later 100.

Another was 69 with sob for a few days. Some intermittent burning pain. Very low level. Ekg showed non specific ekg changes. Trop was 650. Trop one hour was 600. So is this a nstemi. Seems like high trop and by algorithm trop shouldnt be rechecked.

Our cardiologists seem to be quite unknowledgable about this values and poo poo the numbers.

Dr. Mattu references evidence for early discharge of patients with a HEART score of 4-6 with negative high sensitivity troponin. From the articles I've reviewed, patients in this category have been placed in observation or admitted, typically with some type of provocative testing. Is there somewhere specific this reference was coming from. We're implementing high sensitivity troponin very soon in our hospital, and this specific patient population (0hr and 2hr hs-troponin I <99th %ile, but HEART score greater than or equal to 4) raised some concerns amongst the EM physicians. Thank you for any info you can provide.