Simple Lab Score Beats Troponin for MI Diagnosis in the ED

[Lawpy]

From Medscape

Journal article: Clinical chemistry score versus high-sensitivity cardiac troponin I and T tests alone to identify patients at low or high risk for myocardial infarction or death at presentation to the emergency department

Clinical chemistry score is defined as the following:
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Some takeaways from the article:

"Adding glucose level and estimated glomerular filtration rate (eGFR) to high-sensitivity cardiac troponin (hs-cTn) level testing in the emergency department (ED) is more sensitive and specific for determining risk for myocardial infarction (MI) and death in patients with MI symptoms than hs-cTn testing alone, a large international study shows."

"Although some experts have suggested using a single hs-cTn for early triage in the ED, the test is known to show variation in the low range, which makes it inadequate as a standalone test... To improve on the situation, they developed a clinical chemistry score (CCS) combining glucose concentration, eGFR, and hs-cTn on the basis of the value that each contributes to the assessment of patients with MI symptoms."

"Elevated glucose concentrations in patients with ST-segment elevation MI can indicate the patient is hemodynamically unstable, has a larger infarct size, and has increased risk for death within 30 days. When calculated by the Chronic Kidney Disease Epidemiology Collaboration creatinine equation, eGFR independently predicts major adverse cardiac outcomes in those with acute coronary syndrome, the authors explain."

"A CCS score of 0 points on a scale of 0 to 5 was most reliable at identifying patients at low risk. Using hs-cTnI, sensitivity was 100% (95% confidence interval [CI], 99.5% - 100%) with no false negatives. The CCS classified 8.9% (95% CI, 8.1% - 9.8%) of the patients as having low risk."

"A CCS score of 5 points was most reliable at identifying patients with high risk. With hs-cTnI, specificity was 96.6% (95% CI, 96.0% - 97.2%), and the positive predictive value was 75.1% (95% CI, 71.3% - 78.5%). Using hs-cTnI, the CCS classified 11.2% (95% CI, 10.3% - 12.2%) of the study population as having high risk."

What are your thoughts? Could this new lab score be eventually adopted in clinical practice?
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[southerndoc]

Needs validation before you can even proceed. Will be nice to compare this with HEART score, which has been well validated.

 

[Lawpy]

Needs validation before you can even proceed. Will be nice to compare this with HEART score, which has been well validated.

Good point. Just wanted to clarify on one question though. If this clinical chemistry score is validated and is found to be better than troponin alone, could the HEART score be modified to include the new clinical chemistry score?

 

[gamerEMdoc]

Sure. But why would you need to? A heart score of 0-3 already gets you down to a 1.7% risk of MACE in 6 weeks. A second troponin gets you down to less than 1%. That's as good of a negative predictive value as you are going to get in medicine.

And that is MACE, which combines patient oriented outcomes like STEMI and death with things like "patient got a stent for a stable lesion" which has no mortality benefit. If you only include patient oriented outcomes like STEMI, NSTEMI, death, or arrythmia, the risk of is way way lower. Scott Weingart had a study in JAMA that showed a risk of bad outcome of all admitted chest pain patients (not just low risk) to be way under 1% if you had 2 negative trops.

 

[Instatewaiter]

It also doesn't describe how they define MI. If they didn't use angiography it is basically circular logic ...

We all know a positive troponin not related to a real type 1 MI is just a marker of being sick. Sick people die more often .

 

[thegenius]

First, the study has >4,200 participants and 17% of them had an MI within 30 days? That seems awfully high. If 17% of all my chest pain patients had an MI within 30 days, I would be admitting every single one of them. So something is a little pfooey with that.

Logically, the addition of glucose (diabetes) and GFR (CKD or ESRD) appears to be adding points for risk factors to your current likelihood of having an MI in the ED. And we all know that there are only a few important questions that one needs to ask for active chest pain. Risk factors like diabetes, HTN, HL, have never been shown to actually matter if someone is having an MI in the ED.

I would have to read deep into the data to see if the differences between the groups is clinically significant. I agree with the above poster, two negative troponins gets you under 1% and it doesn't get much better than that.