CK-MB inACS

[tyson]

I hate CK-MB. I hate it when I just order a trop and the admitting doc asks me what the CK-MB is. How often do we see an elevated CK-MB with normal serial trops? All the time. 

I get that there might be some slight utility when patient had recent cath and has chest pain (troponin released in 2-3 hours, peaks at 12 hours, resolves in 7 day. CK-MB is realeased in a couple hours, peaks at 12 hours and resolves in 2-3 days). But even then, EKG and hx is going to guide you. 

Below is support for this stance. 


1. Do we still need to send CK-MB’s when testing for ACS?



Le RD, Kosowsky JM, Landman AB, et al. Clinical and financial impact of removing creatine kinase-MB from the routine testing menu in the emergency setting. Am J Emerg Med. 2015;33(1):72–5. PMID: 25455047.



Summary:



Troponin (TN) testing has become standard

Correlates with prognosis

Incorporated into the universal definition of myocardial infarction

CK-MB was removed from cardiac lab panel at large academic medical center (BWH)

CK-MB could still be ordered manually by physicians

Data collected during a 12 month period (6 months pre- & post-removal of CK-MB from panel)

Specimens with normal TN’s, but elevated CK-MB and CK-MB indexes were considered discrepant, and independently reviewed by 2 ED physicians for presence of ACS and documentation of final diagnosis

Of 6444 cases included in the analysis, only 17 were discrepant

Of all 17 cases, no patients were diagnosed with ACS

Removal of CK and CK-MB from the panel translated to ~ $47,000 in savings

Conclusions:



CK-MB can be removed from the routine ED cardiac panel without adversely affecting patient care. Substantial cost savings can be achieved by reducing unnecessary CK-MB and associated CK orders.

[pbruss]

i dont like ckmbs and do not order if symptoms more then 6 hours. as far as this paper goes i would love to read the whole thing but i can not find it online with out paying and im cheap. if you have the whole paper please post it tyson. i am interested in how they defined the outcomes. looks like 2 ed docs went through the chart to determine if these patients did have ACS when the CKMB was up but the trop was normal. What were they looking for? did these patients get admittied, did they have a cath, did they have serious enzymes? 

i also think CKMBs add a legal liability. tyson et all, answer the following question but i want you to pretendt like you are on teh stand and a lawyer is asking:

"Dr. Tyson, what is the definition of a heart attack?"

[pbruss]

by the way, there is a good summary of this on ecgweekly.com where you probably got it. if you want to see it you can use my info.


username :[e-mail]
password: brussface

[Bjs04f]

Troponin is king – why even send an CK?
Le RD et al. Clinical and financial impact of removing creatine kinase-MB from the routine testing menu in the emergency setting. Am J Emerg Med. 2015;33(1):72-5. PMID: 25455047

This is an observational study, looking at a period before and after CK-MB was removed from an automatic order set. Out of 6444 cases included in the study, there were only 17 cases with a positive CK-MB fraction and a negative troponin. All 17 were ultimately determined by the treating physicians to have non-ACS causes (ie, they were false positives). So, CK-MB was not clinically helpful. Removing it from the order set dropped ordering by 80% and saved the hospital about $47,000 a year.

Bottom line: We might want to keep this one in our back pocket for the next time the hospital demands cost savings – dropping the CK helps us and saves money

[Bjs04f]

yup same article

[pbruss]

moron. also i forgot to mention in my original critique that this paper did not have significant power. the sample size was very very small and from what i remember from stats the larger the prevalence of the disease in the population you are studying the larger the sample size should be. I dont know the exact number but i assume hundreds of thousands or millions of patients are diagnosed with ACS each year in America.

and for the legal stuff. the WHO defines a heart attack as angina symptoms with eighter ST changes or a rise AND OR fall in cardiac markers including CKMB and Myoglobin. can you imagine being on the stand for a case you sent home and the patient died and the laywer reads you this definition and shows the labs with a slightly high CKMB. also imagine the same thing but you checked 2 sets of markers and the second was lower then the first. both these cases fit the WHO definition of a heart attack. thus sometimes high CKMBs do make me second guess my decision in pratice. 

[kemple]

ahh but if you don't order the ckmb the lawyer can't an argument of it was high