Thread by @sargsyanz

I haven’t ordered a CK-MB in 8 years.

If you’re worried about the ❤️, it adds nothing to your troponin.

If you’re worried about 🥩💪🏽, it adds nothing to CK.

Many hospital/labs don’t even run CK-MBs, considering them too low-value.

#TipsForNewDocs

Thanks for comments, y’all. Regarding utility in detecting reinfarction:

First, I must say that I do hospital medicine and minimal ICU, so this isn’t a daily quandary for me. I was mostly imagining the “new docs” on the wards.

That being said, some thoughts/references:

1/7

First, the whole idea is that MB may have an earlier rise than troponin, and a quicker fall (especially if low GFR).

As such, in back to back events, there may be a clearer separation of humps in the MB curve.

You may have seen curves like this (Wikipedia)

2/

Some try to apply these kinetics in practice. I used to, but my CCU attendings convinced me that between symptoms, ECG, and troponin, there’s little value added by CKMB in most cases.

Here’s perspective from UTD authors:

3/

But even isolating the biomarkers alone, here is a nice series of 3 patients with reinfarction demonstrating that CKMB is redundant when you have access to troponin.

PMID 15563477

4/

Before tweeting the original post, I texted two trusted cardiologists, who trained and practice at different institutions. Caveat, only one is an interventionalist.

5/

Parenthetically, troponin peak correlates with infarct size and prognosis too. Though some question even ITS practical value post-reperfusion, and choose not to trend it to peak.

PMID 16275971

6/

All in all, I think routine use of CK-MB is low value, even in patients with possible reinfarction. But there may be occasional times where it’s useful (certainly if troponin not available).

What I’d very strongly discourage is this, in a patient with mild rhabdo:

7/7

@Doc_Fomin @drfudk @Ladiazsm @aflakyguy