Coagulation Basics

This is Lab Medicine Rounds, a curated podcast for physicians, laboratory professionals and students. I'm your guest host Anne Moyer, a pathologist and laboratory genetics and genomics and associate professor of laboratory medicine and pathology at Mayo Clinic. Today we're rounding with Justin Kreer a transfusion medicine pathologist and assistant professor of laboratory medicine and pathology at Mayo Clinic to discuss understanding the fundamentals of coagulation. Welcome Justin.

I'm really excited to talk with you today about this topic. Hey, thank you so much. Me, me as well. Well, let's go ahead and jump right into this exciting topic. So the first question I've got for you is, why is it important for physicians to

understand the fundamentals of coagulation? I mean, those are some pretty complex pathways. Well, you know, I guess first off it makes my heart go pitter patter. I, I love it. But I guess more, more importantly besides my own joy for it is I, I, I think it it's generally complex like you're, you're saying it's a lot of pathways and, and aspects to things and and I think a lot of physicians have a lot of things that are trying to juggle at the same time.

Same things for us in pathology lab medicine. I think we have a lot of things that we're trying to stay on top of. And so if you have something complex, it it's really tough to kind of keep things fresh. Right. Because I, I guess I kind of joke sometimes that I only remember what I read the night before. So it, it's complex and then, you know, it it really matters, right?

When we're looking at patients if patients are bleeding and we need to figure out how what's gonna be an effective way to help them stop bleeding we need to understand some fundamentals to kind of figure out that puzzle. Likewise, if, if somebody is thrombosing on the other side of the fence, right? I mean this is, this is another, you know leads to horrible outcomes, heart attacks, strokes.

At the end of the day, it's important for all of us to have a couple of fundamentals about how coagulation works so that we can deal

with this complexity when it matters for patients. Well, that makes a lot of sense. It definitely is a very important system and in many of the contexts that you've already mentioned. So since you end up talking with people about coagulation a lot, in your experience, what are a few of the common misunderstandings that people might have?

Yeah, I, I think the, the big thing and, and again I'm not throwing shade on on somebody I can appreciate it is just the, the simplifications that are drawn, right? I mean, a number of years ago very much there was a lot of focus on I N r. Basically, I think coagulation sort of just got boiled down to whatever that i n R value. And, and that was, that was it.

You know, I used to consult on patients many times bleeding out, and the only thing that's really been looked at and trended is what their I n R value is. Not that labs are the end all be all, but you know also just an appreciation for what is that clinical history for that patient. The medications that they're on really mattering potentially quite a lot.

And then in more recent years, right, viscoelastic testing so tag rotem, you know, has really, I think taken over especially for our surgical colleagues has kind of taken center stage and now I think they have maybe, you know had those experiences to realize that I and R is not the end all be all. But now a lot of times I think TAG has has become that for them. And again, I can understand why that is.

You know, I think TAG is incredibly useful in patients that are experiencing a major and significant bleed. And so I think that our surgical colleagues have seen it help in those situations and and sort of have learned that that can be helpful. And then the, the challenge that comes is then they'll oftentimes extrapolate that out into the non bleeding patient.

So for example, I one time was talking with a colleague that like wanted to do a tag on some outpatient in order to figure out how to I'm using finger quotes here for the, for those listening to the podcast, how to optimize the patient for their surgery in a, in a couple of days. And, and to me that's very much not the context.

If, you know, once you understand the principles of how viscoelastic testing works, you know, if if somebody is out grabbing lunch somewhere and you have an abnormality, what does that mean? And then on, on the inverse, a tag does not catch everything that is a clinically significant bleeding risk. And so even a normal tag could be misleading. So, you know, good, good things. You know, I, I like the I N R in certain situations. I like that tag in, in certain situations.

Another example that comes across, I've I've had people kind of bemoan the fact that, you know we don't do bleeding times anymore. And I think that's just a reflection of the name of the test, right? It seems so perfect that, you know, hey, let's let's lance you and then we'll measure how long you bleed.

That seems like the perfect, like correlate for how we should be measuring or what we should look be looking at with the lab test until you figure out that, oh that test was really only a good test for kind of the what we call the primary hemostasis. So the, the von Willebrand factor and, and platelets. But you know, none of these anticoagulants aren't really gonna be reflected in that bleeding time.

So yeah, this over-relying and, and I guess one more example since I'm a transfusion medicine physician, right? Is this idea of, oh, well, you know, if somebody's bleeding like we can just get them to stop bleeding with fresh frozen plasma, you know, and of course that is sometimes what people will reach for but depending on what the clinical situation is if there's an an inhibitor on board those couple percent of coagulation factors aren't really gonna make a a difference.

So I think the common misunderstandings kind of for me all file under this kind of simplifications which I think is just a reflection of it's a complex system and many of us, you know, haven't been taught it. And, and in a way that we can kind of get our arms around it. And, and that probably includes or I know that includes me as a teacher. I think one of my, you know, genesis in this area was the fact that I tried to teach coagulation to a resident once, kind of in a one-stop shop.

And, and just then realizing the next day when there was a clinical situation that came up and I was like, oh, you got this, you know, I taught you I gave you the keys to the kingdom and you understand it all. And they looked at me like, you know, Dr. Gr, I, I do not remember a single thing you said. Right? So they, they complex and the way we convey it, you know people are trying to adapt and overcome as best they can. So, but simplifications are

are really the, the big misunderstanding. I see. And, and unfortunately I think that gets to the patient's bedside. I think that makes a lot of sense. I think human nature is such that when we've got something that's very complicated that despite our best efforts, we've tried to understand it but it's still complicated and confusing. If we don't have a really solid foundation it's easy to fall into oversimplifications.

So I guess with that in mind it's probably important to make sure that medical students come out with a really strong foundation in coagulation so that they can avoid some of these pitfalls. And since I know you have a passion for education do you have any thoughts on what we could do better to teach a complicated topic like coagulation? Yeah, well, pinging on your question for a second.

You know, that's one of the challenges that I still struggle and reflect on is trying to teach somebody about coagulation before they really have experience seeing patients bleed. So I know that I am a lot more effective when I teach the anesthesia residents who rotate through transfusion medicine, right? 'cause 'cause for them, it's not such an, an abstract topic but for somebody who's a, a first year or second year medical student, you know, this concept is is really kind of nebulous.

They don't have the clinical experience yet to kind of hang their, their hat on the on the coat rack kind of thing, so to speak. But a few, a few things that I think are really helpful are just kind of some of the fundamentals of how do we learn and teach, you know, so for example the idea of spaced retrieval practice, right?

So my time of do, of teaching the, the resident all of coagulation, like in one, like sit down like session in the break room over the course of a about an hour is, is just too much too fast, right? So nowadays what I do a lot of times is I break those up into sessions. So, you know, the first session I'll talk about, you know how do we initially form the platelet plug and and plasmatic coagulation those factors.

And then I'll come back another time and they'll have to tell me how that initial thing worked. And then we'll start talking about the endogenous anticoagulants and how that works. So then we'll come back a third time and they will again take me through everything we've learned so far. And then we'll start talking about the fi lytic aspects of coagulation.

And so by kind of spacing it out and revisiting it, the educationalists in the world would say we're interrupting, forgetting, and and building stronger memories. Another way I try to do it is I try to make it explicit and concrete. 'cause like, if we just sort of say these things and they're just sort of out there as this amorphous these these words, you know, it, it's really hard for I think learners to really understand what this means.

And so I use very concrete examples in that I actually will put either, you know, playing cards and poker chips to help people understand the physicality of what's going on. And I think that really makes a big difference when we put things down and people can then visualize what is actually happening when somebody, somebody is bleeding out and what needs to happen for them to stop bleeding. And then also it's, it's a lot of times connections to what they already know.

And that's probably where the more advanced learner the anesthesiologist, right? They understand certain medications they understand certain reversal agents but when we go through this they can understand why that is what they're going to. And you see these, you know light bulbs go off as they can make connections and the people that can make connections to what's already learned. That's another way that educators are making it a more robust memory.

And I think that's one of the challenges of teaching it initially is what can we kind of relate it to. And so that's why I do things like one example is when we talk about platelets getting activated, I I sometimes give the analogy of it's like going clubbing with your friends, right? How do you know you're approaching the nightclub, right? Like you, you hear, you hear that techno music going you can see the glow sticks going and you can smell the, the cheap cologne or perfume.

And, and so I kind of use those three and then I talk about how, you know if you have somebody that is on Plavix and aspirin two medications that inhibit platelet function we've talked about what that mechanism is. We can say, Hey, you could have earmuffs on and have your, you know, your nose plugged up, but you know you can still see the glow sticks going on to kind of explain, you know, the the redundancy that mother nature has given us to platelet activation.

So that's where I try to, even if the students don't have a specific clinical situation they can kind of pair it to, I try to make it relatable. Not saying that everybody's going clubbing every weekend

but try, try to figure out a story, right? 'cause I think those stories make it memorable. And then also I avoid all the things that are kind of that nuanced stuff that some of us need to study for our boards. You know, which glycoprotein is grabbing onto Von Willand factor which glycoprotein is binding onto fibrinogen.

But you know, for your average learner that's, you know additional details that kind of, I think get in the way of you know, when I have somebody bleeding in front of me what do I need to be doing and thinking about? I think those are all fantastic strategies and I have to admit that even though I'm not much of a partier I definitely think that that platelet party sounds like a lot of fun to hear more about someday.

So I may have to, to find out a little more about that analogy for the people though that don't necessarily have the luxury of having one-on-one education sessions because maybe they're already in practice. I think another good opportunity can be attending conferences. And as such I heard that we've gotten upcoming breeding, bleeding and Thrombosing diseases conference that'll be here in Rochester soon. And are there any sessions that you are looking forward to in particular at that conference?

Yeah Yeah. Well, I'll be presenting and talking about, you know, coagulation fundamentals. So I think but I think the favorite one that I'm really looking forward to is Dr.

She Harden is gonna be talking about factor 13 deficiency in inhibitors. And for me that's, that's something that deepened my soul I think is a lot more prevalent a challenge in our hospitalized patients. And we're recognizing, I think that a lot of the reason that it has been under-recognized is because there's a lot of limitations for testing and how do we assess it.

So I'm really kind of excited to, to get that update from her and understand if we, how we have new tools and how do we go about kind of assessing factor 13 deficiency and addressing it. That sounds really exciting. I think going to conferences is a good way to touch base with a subject maybe you've learned about in the past but especially when there's new cutting edge things that are there too, that makes it even more exciting for people of all skill levels to be attending.

So thanks for telling us about that. Yeah, thank you. I'll see you there. Great. I think I'll be signing up for that one. Well, for everybody else, join us for the 18th bleeding and Thrombosing Diseases conference to be held in Rochester Minnesota and live streamed October 4th through sixth 2023. Visit Mayo clinic labs.com/bt 2 0 2 3 for more information. So we've been rounding today with Dr. Kreer about understanding the fundamentals of coagulation.

Thank you so much again for taking the time to discuss this exciting topic with us. If you'd like to hear more on this topic, Dr. Kreider will be presenting at the 18th Bleeding and Thrombosis Diseases conference in October. Again, please visit mayo clinic labs.com/bt 2023. For more information to all our listeners thank you for joining us today. We invite you to share your thoughts and suggestions via email to MCL [email protected].

If you have enjoyed this podcast please subscribe until our next rounds together. We encourage you to continue to connect lab medicine and the clinical practice through educational conversations. Thanks again.