#EuSEM18 How I learned to stop worrying and love the dimer

This has been around for a while. I did my CTR for the FRCEM on the topic. The data is all observational and of variable quality

The Righini paper is the big one here.

There is of course a false negative rate – you will miss a very occasional patient by using this strategy. however you will also miss PE with using a convention strategy. In the Righini paper it was 0.1 v 0.3

The major limitation here is that it only applies to the over 50s if you’re 35 your cut off is still 500 in this protocol. if you’re 85 then your cut off is 850 but it’s hard to see the downside of doing a CT on an 85 year old. The contrast nephropathy probably is non existent and the chance of serious pathology (PE or otherwise) is so much higher in this group.

So at its most basic the AADD reduces testing in people who i’m not in a rush to reduce testing in.

It has recently been endorsed by ACEP in their updated VTE policy so you now have a guideline to back you up (it is not as yet endorsed by ACCP or the ESC guidelines)

All studies seem to make some horrifically forced acronym out of the title. (PARAMEDIC2 is a good example…) This one is apparently the YEARS study. Though I didn’t see them even make any attempt to explain where the YEARS came from. I suggested this…

They modify the Wells criteria to just 3 questions.

Your d dimer cut off is therefore dependant on your clinical risk.

My big concern with this paper is that the d dimer was done at triage before the assessing doctor answered the 3 questions. You can imagine that knowing the result of the dimer might change how you assign your pre test probability. Say you have a young female with a dimer of 950 and score negative on the other 2 questions of the YEARS protocol. The question “Is PE the most likely diagnosis” could be easily swayed by that knowledge.

Honestly i think either are reasonable to use, certainly as part of a departmental protocol you’d be well supported. I think they’re both similar in terms of their evidence base and they both provide safe and modest reductions in current imaging levels.

This is an obvious question and the age adjusted dimer is jsut starting to be studied for this. So far it seems the reduction in imaging is even more modest and given the limited harm in just doing it yourself or getting a formal ultrasound then I can’t see it being great benefit.

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RCEM Learning: Andy Neill & Dan Horner