Bruce - here's an in depth written review of the article: https://rebelem.com/peged-study-is-it-safe-to-adjust-the-d-dimer-threshold-for-clinical-probability/
I'm a little confused on not using D-dimer in intermediate risk patients. My practice is to rule out PE in intermediate risk patients with a negative D-dimer. UpToDate supports that, although it does say some people go straight to scan with a Wells score of 4-6. Most recent ACEP clinical policy says age-adjusted D-dimer can rule out PE in intermediate risk patients.
Steve - easy to get confused on this. The straight Wells score has three categories but there's also a dichotomized Wells that many providers use where < 4 is low and >/= 4 is high risk (ie no moderate group). So in this scheme, < 4 gets a dimer and >/= 4 goes to CT. Even in the three tier, many clinicians go to dimer in the moderate group which is where this study changes things.
Steve, you are, in fact correct. Ordering a D-Dimer in "intermediate risk" patients has been supported by guidelines since 2015 (American College of Emergency Physicians, American College of Physicians, American Society of Hematology, and the European Society of Cardiology). D-dimering these patients in PEGeD was NOT novel. I have a paper coming out in Acad Emerg Medicine soon on this topic and how researchers have messed up the risk stratification game, particularly in the US where even the "intermediate" risk group generally has 12-18% chance, or LESS, of PE by attempting to simplify things (i.e. dichomotize, etc).
Lauren - thank you for clarifying. Steve - thank you for pointing this out. Lauren - Are you using the three tiered Wells in general or the dichotomized?
I am using the three-tiered Wells. I was initially trained in the dichotomized Wells, I think due to simplicity (people didn't know what to do with low risk wells) but after spending the past few years doing research for my K12, I became acquainted with the body of literature supporting D-dimer for intermediate-risk patients and converted (https://shortcoatsinem.blogspot.com/2020/01/d-dimer-in-patients-at-intermediate.html). Prior to PEGeD, my use of the trichotomized score was generally dichotomous (are you ≤ 6 and "dimerable" or >6, with the exception of times I applied Wells -> PERC in which case it's controversial which cut-point, 2 or 4, you can use...that is a different conversation with less rigorous evidence). PEGeD really gave value to that Wells 0-2 group (and extended it to 4!) by allowing a dimer threshold of 1000 ng/mL. While this may not be valid in Europe where prevalence is generally ~20%, int North America where our prevalence is ~10%, it looks good.
Bruce L. - January 26, 2020 10:35 AM
Can you post a written summary? I am trying to digest what you just said but I am more of a visual learner in this type of algorithm discussion.
Anand S. - January 26, 2020 10:42 AM
Bruce - here's an in depth written review of the article:
https://rebelem.com/peged-study-is-it-safe-to-adjust-the-d-dimer-threshold-for-clinical-probability/
hope that helps
Bruce L. - February 7, 2020 5:28 PM
That is helpful as are the discussions below. Now I need to get the article and digest. Thanks.
Steve D. - January 29, 2020 9:17 AM
I'm a little confused on not using D-dimer in intermediate risk patients. My practice is to rule out PE in intermediate risk patients with a negative D-dimer. UpToDate supports that, although it does say some people go straight to scan with a Wells score of 4-6. Most recent ACEP clinical policy says age-adjusted D-dimer can rule out PE in intermediate risk patients.
Anand S. - January 29, 2020 12:01 PM
Steve - easy to get confused on this. The straight Wells score has three categories but there's also a dichotomized Wells that many providers use where < 4 is low and >/= 4 is high risk (ie no moderate group). So in this scheme, < 4 gets a dimer and >/= 4 goes to CT.
Even in the three tier, many clinicians go to dimer in the moderate group which is where this study changes things.
Lauren W. - January 31, 2020 7:48 AM
Steve, you are, in fact correct. Ordering a D-Dimer in "intermediate risk" patients has been supported by guidelines since 2015 (American College of Emergency Physicians, American College of Physicians, American Society of Hematology, and the European Society of Cardiology). D-dimering these patients in PEGeD was NOT novel. I have a paper coming out in Acad Emerg Medicine soon on this topic and how researchers have messed up the risk stratification game, particularly in the US where even the "intermediate" risk group generally has 12-18% chance, or LESS, of PE by attempting to simplify things (i.e. dichomotize, etc).
Anand S. - January 31, 2020 10:55 AM
Lauren - thank you for clarifying. Steve - thank you for pointing this out.
Lauren - Are you using the three tiered Wells in general or the dichotomized?
Lauren W. - January 31, 2020 11:26 AM
I am using the three-tiered Wells. I was initially trained in the dichotomized Wells, I think due to simplicity (people didn't know what to do with low risk wells) but after spending the past few years doing research for my K12, I became acquainted with the body of literature supporting D-dimer for intermediate-risk patients and converted (https://shortcoatsinem.blogspot.com/2020/01/d-dimer-in-patients-at-intermediate.html). Prior to PEGeD, my use of the trichotomized score was generally dichotomous (are you ≤ 6 and "dimerable" or >6, with the exception of times I applied Wells -> PERC in which case it's controversial which cut-point, 2 or 4, you can use...that is a different conversation with less rigorous evidence). PEGeD really gave value to that Wells 0-2 group (and extended it to 4!) by allowing a dimer threshold of 1000 ng/mL. While this may not be valid in Europe where prevalence is generally ~20%, int North America where our prevalence is ~10%, it looks good.
Melinda N. - February 21, 2020 9:41 PM
I too am a visual learner and would appreciate a written summary of some kind
thank you
Anand S. - February 24, 2020 10:01 AM
https://rebelem.com/peged-study-is-it-safe-to-adjust-the-d-dimer-threshold-for-clinical-probability/