February 17, 2023 • 24 mins
In this episode, Dr Dante Yeh is joined by Sharven Taghavi, MD, MPH, MS, FACS, from the Tulane University School of Medicine. They discuss his study on blunt cerebrovascular injury (BCVI), which is a significant cause of morbidity and mortality in patients with blunt trauma. Using a Markov decision analysis, the authors found that universal screening for cerebrovascular injury using CT angiography in blunt trauma victims was the optimal strategy.
Disclosure Information: Dr Taghavi receives funding from the CDC. Dr Yeh receives author royalties from UpToDate, advisory panel/training honoraria from Takeda Pharmaceuticals, and advisory panel honoraria from Baxter, Eli Lilly, and Fresenius Kabi.
To earn 0.25 AMA PRA Category 1 Credits™ for this episode of the JACS Operative Word Podcast, click here to register for the course and complete the evaluation.
Learn more about the Journal of the American College of Surgeons, a monthly peer-reviewed journal publishing original contributions on all aspects of surgery, including scientific articles, collective reviews, experimental investigations, and more.
#JACSOperativeWord
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
(00:01):
Welcome to the Operative Word,
a podcast brought to you by the
Journal of the American College of
Surgeons.
I'm Dr. Jamie Coleman.
And throughout this series, Dr.
Dante Yeh and I will speak with
recently published authors about the
motivation behind their latest
research and the clinical
implications it has for the
practicing surgeon.
(00:22):
The opinions expressed in this
podcast are those of the
participants and not necessarily
that of the American College of
Surgeons.
Welcome to the Operative Word, a
podcast from the Journal of the
American College of Surgeons.
I'm Dr. Dante Yeh, one of your
co-hosts for the series.
In this episode, we'll be taking an
in-depth look into the current
(00:43):
article, Cost Effectiveness
of Universal Screening for Blunt
Cerebrovascular Injury A
Markov Analysis.
I'm honored to be joined today by a
senior author, Dr. Sharvin Taghavi,
MD, from Tulane University.
Dr. Taghavi, thank you for joining
me today.
Before we begin, do you have any
potential conflicts of interest to
disclose?
I do have some funding from the CDC,
(01:05):
but none of which is relative
to or related to this research
specifically.
Great. Thank you for the disclosure.
Can you give us a brief summary
of your study design and just and
describe to us your main findings?
Sure. So BCVI
is really interesting in that over,
you know, really three decades of
time, the pendulum has
(01:25):
continued to swing and things have
changed and been driven by research.
So one thing that
if you look at the literature
related to this that seems to be
changing now is that a lot of places
are adopting universal screening
where basically pretty much every
trauma patient is getting a CTA,
some exceptions, obviously, and
looking for a blunt cerebrovascular
injury. And a lot of studies have
(01:45):
shown that using some traditional
screening criteria, you're going to
miss anywhere from 10 to 20%
of blunt cerebrovascular injuries.
So as more and more reports of
universal screening have come out,
we wanted to look at how
a universal screening strategy
might affect cost effectiveness
in terms of treating and screening
for BCVI.
(02:06):
So we used Markov decision
model, and a Markov decision model
is basically a mathematical model
that uses probabilities to simulate
future transitions from one disease
state to another.
In this particular case, different
disease states could be a missed
BCVI or a diagnosed BCVI.
And then it kind of models
are based on probabilities two
different transitions relevant
(02:27):
to this study. Those transitions
could be a stroke, it could be
nothing. And, you know, regular
recovery from blunt trauma or
death from stroke.
And in a cost analysis
and a Markov decision model can
compute the relative cost of each
pathway that you go along,
as well as the quality of life
that's accumulated within each
pathway.
(02:47):
It then uses a kind of sophisticated
mathematical analysis to determine
whether a change in treatment, in
this case universal screening
versus different types of screening,
and determine if that's cost
effective using some benchmark
so that the literature has
kind of proven to be
cost effective.
Great. And tell us, what were the
(03:08):
main findings of your Markov
analysis?
Sure. So what we found out was that
universal screening did appear
to be more the most cost
effective method of screening.
And we looked at Denver criteria,
extended Denver criteria, Memphis
criteria, and no screening at
all. And although we know that
pretty much no one at this stage
(03:28):
does, no
screening, we still included
that in the model as a baseline.
And what we found was that universal
screening, when you looked at the
cost of missed BCVI
and the various different pathways
along the decision tree analysis,
universal screening did appear to be
the most cost effective
(03:49):
method of screening.
Now, that came with a couple of
caveats. So, one
of them is how common
BCVI is.
So, prior to,
there was a great study from
one of our coauthors Jonathan Black
out of UAB.
Prior to his study,
the incidence of BCVI was thought
to be between 1 and 3%.
(04:11):
His study showed that actually, with
universal screening, the
incidence of BCVI is actually much
higher. He found it to be
as high as 7%.
So, we found that if the incidence
of BCI falls between 2.6
and 6%,
universal screening is actually,
excuse me, extended Denver criteria
(04:31):
is actually the most most
cost effective screening.
Now if you're incidence ABC
BCB is over 6%,
then universal screening actually
becomes the most
cost-effective method of screening.
Now the second caveat is that
looking at how effective
antithrombotic therapy is and
(04:53):
we used we use antithrombotic
therapy because that's probably the
most common know.
Some sometimes people use a heparin
drip or following anticoagulation,
but we looked at antithrombotic
therapy and so.
Using.
If you look at the Eastern practice
management, Eastern
Association for the Surgery of Traumapractice
(05:13):
management guidelines
in 2020, they did a meta-analysis
looking at the
effectiveness of antithrombotic
therapy after BCVI.
And what they found through the
meta-analysis was that the odds
ratio of stroke was about 0.2%.
So that's the number we kind of used
for the model.
However, when we did a sensitivity
(05:35):
analysis, what we found was that
if the ratio of
antithrombotic therapy after
BCVI for stroke is 0.35
or less, then universal screening
is the most cost effective.
If antithrombotic therapy is not
as effective as we think it is, if
the odds ratio of stroke is above
0.35, the expanded
(05:56):
Denver criteria is the most
cost-effective therapy.
That makes a lot of sense to me.
If the incidence
of the disease
that you're screening for is
higher, then it makes
more sense to screen for it
more vigorously.
And if it's lower, then it's less
cost effective to go looking for
(06:17):
if it's a more rare entity.
And similarly, if the treatment that
you have available to treat
it is less effective,
then it's going to be less cost
effective to diagnose it in the
first place if your treatment is not
even going to work anyway.
Right?
So yeah, that seems to a
that seems to make sense to me
(06:37):
from a from a you know, a
very unsophisticated statistical
understanding. It totally makes
sense.
I want to back up for a second.
You mentioned the expanded Denver
criteria and you
you mentioned that in your model,
you sort of looked at the whole
spectrum of behaviors
ranging all the way from no
screening to universal
(06:58):
screening.
And you mentioned also the Memphis
criteria and the Denver criteria.
And I assume I'm assuming that these
falls somewhere within
that spectrum.
Can you sort of give the readers,
if they're not familiar with these
criteria, can you give us a rough
description of the three different
(07:19):
screening criteria that you entered
into your model?
Sure.
So, yeah, so we modeled with Denver
criteria, extended Denver criteria,
Memphis criteria, all
three kind of named after the
institutions that kind of came
up with the screening strategies.
You know, there are a lot of nuanced
details that make them different.
(07:40):
But in generality, the
Memphis criteria
kind of focuses more on,
you know, cervical spine injury.
So if there's any sort of cervical
spine fracture, as well
as facial fractures such as LeFort
two and LeFort three, when you
move to the Denver criteria,
it's a slightly more inclusive.
(08:01):
I talks about having,
you know, if there are severe
there's a lot of physical findings
that go in to the cervical bruit,
you know, altered mental status with
cervical trauma.
If you have a you know, I
think all of them kind of talk about
having a mental status that's not
consistent with CT
findings. And you want to get a CTA.
The Denver criteria is a little more
(08:22):
inclusive with facial fractures, for
example, it adds on mandibular
fractures and even
significant cervical soft tissue
injuries.
And extended Denver criteria
is even more inclusive and
adds on some things such as
injury mechanisms like a near
hanging clothesline
(08:42):
type injuries.
It kind of specifies,
you know, closed head injuries with
diffuse axonal injury as well.
So with extended Denver
criteria as again,
over a couple of decades as
as you know, research
became better and our
community kind of
(09:02):
increased the data that is
available.
The screening criteria kind of
became more inclusive and added
more criteria to the screen
patients.
It kind of reminds me of
the paradigm shift in cervical
spine fracture screening
where, you know, we were talking for
a while about NEXUS and
Canadian C-spine, and
(09:23):
by the time you get the Canadian C
spine, you're basically doing
universal screening anyway.
So as we find more and more of these
injuries with lower
and lower mechanisms, it seems like
we're expanding our criteria even
more so that we're basically
approaching universal screening.
Yeah, actually, I think that's a
great point because I think as
more and more places adopt universal
(09:45):
screening, we're going to have a ton
of data.
And, you know,
I think that it's going to get even
more nuanced, I guess.
Universal screening is pretty
straightforward, just screening
everybody. But I think that
eventually, as we accumulate more
data, we'll be able to get more
nuanced with our screening.
So I want to take
this moment to ask for some
clarification about what you mean
(10:06):
by a universal screening,
because as trauma surgeons, we
see the tip of the iceberg,
at least at my institution, where
there's a lot of low level traumas
that are evaluated by our
emergency medicine colleagues and
are worked up and then are
never even brought to our attention.
(10:26):
So, you know, in a typical trauma
center, there's, well, how many do
you see in the ED?
How many are admitted?
How many have a injuries severity,
score over 15, etc.?
What do you mean—in your study
how did you define universal
screening? Was there anybody let's
say they got kicked in the stomach
by a horse.
Would that person get universal
(10:46):
screening or do they have to meet
a certain activation level,
like the highest level of, you know,
for example, trauma team activation?
Or do they have to have a certain
energy mechanism?
Can you can you clarify that for me?
Sure. Yeah. And that's a great
question because, you know, it turns
out there's really not an accepted
definition of universal screening.
And I bet if you polled different
institutions and even actually
(11:08):
use a loose universal screening, if
you called the different trauma
surgeons that are taking call at our
trauma center in New Orleans, I bet
you you'll get a slightly different
answer from each one of them.
But, you
know, in general, if you look at
prior, you know, prior
work publications, there are
places that are just doing activated
patients.
So for us, what we're used generally
(11:29):
doing is patients that meet level
one or level two, activation
at our trauma center will
essentially get a CTA.
Now, again, there is some
exceptions to that. As you said, if
there's an isolated injury like a
refrigerator fell on my knee
and that patient's activated because
they got a pulseless foot, but they
didn't have any trauma, they don't
(11:50):
have like a high speed mechanism,
then that patient might not get a
CTA.
The place where I think that
has the opposite, the possibility
where you could be missing is, as
you said, the patients that are
seen by the emergency room staff not
activated.
Maybe a trauma consultation occurs,
maybe not.
But I do think in general, if there
(12:11):
is mechanism there, then
we will generally get a CTA.
Is it safe to say that anybody
who's getting a CT of the C spine
should probably get a CTA under
the universal screening paradigm?
Yeah, I think that's a that's a fair
assessment. I mean, that's that's
kind of the strategy I use.
If, if there's enough trauma to
the head and neck region where I
(12:32):
want to have
a CT head and/or a CT C-spine then Ithink a CTA
neck is warranted.
Got it. Got it.
Oh, so let me
pose the question to you.
So I recently had
a patient who had both
a grade one BCVI
as well as a concomitant severe
(12:52):
traumatic brain injury.
And so we spoke
with our neurosurgical colleagues
and they said, no, no,
antithrombotic therapy, no
anticoagulation for the first
72 hours.
And it's my understanding that
that's when the strokes are most
likely to occur for these
BCVIs, the devastating
ones will occur early.
(13:12):
Do you have an estimate for
what percentage of patients
fall into this category where they
have a known diagnosed
BCVI but a contraindication
to early antithrombotic
therapy?
Yeah. So I don't think there's
any any studies
to kind of answer that specific
question.
(13:33):
What I do know is that most of
the literature that
reports starting antithrombotics,
if you look at the average time to
initiation of antithrombotics is
roughly around 2428
afterwards, I think that a lot of
these patients are actually having
some sort of contrary indication
(13:53):
to starting antithrombotics
early.
That being said, you know, it's a
lot of what we deal with.
You know, you're you're you're stuck
between a rock and a hard place.
You know, the vast majority of these
strokes do happen within 72 hours.
So it is very important to weigh the
risks and benefits of
antithrombotics
and to initiate treatment as
early as possible.
(14:14):
And actually, I think most of the
studies there's no randomized
controlled trial, but most of the
studies show that early
antithrombotics
in TBI are relatively safe
and helped decrease
the risk of stroke. So
I think it's a you know, and
(14:35):
you just kind of have to
use judgment and decide what is best
for the patient.
Sure. Sure. Absolutely.
If I'm reading your methods
correctly, though, your model
assumes that all patients
with a diagnosed BCVI
were treated with antithrombotic
therapy, and obviously the cost
effectiveness of a screening
(14:55):
method will decrease if
one cannot act upon the results
of those screenings.
Right. So what good is it if I
diagnose it, if I can't treat it?
Do you have a sense of at what
threshold of untreated BCVI
is universal screening no
longer cost effective, like 50%?
80%?
(15:15):
Yeah. I mean, I think
it's that's hard to say.
I think if you like, in our
sensitivity analysis,
again, we're you know, we're
assuming some sort of benefit
with antithrombotics.
Obviously, if there is no benefit
because you can't treat, then
your cost effectiveness will
(15:36):
differ.
You know, maybe
we didn't look at the model that
way, but maybe even maybe
even something such as no screening
becomes more cost-effective.
Although I wouldn't advocate for
that.
Yeah, I don't think anybody would.
Yeah, it's a great question.
I just don't know that we have the
(15:56):
answer to it.
Well, hopefully
with more screening and more data,
we'll we'll know that answer in
a couple of years.
Let's shift for a second.
So your incremental
cost effectiveness ratio
approach uses
a familiar willingness to
pay threshold of $100,000
(16:17):
per QALY—and QALY stands
for quality adjusted life years—so
100,000 is a figure
that I've been seeing since the
early days of my medical career,
like 20 years ago.
Surely with inflation,
this value must have changed over
time.
And so I was wondering what
is $100,000 for QALY?
(16:37):
Like what?
Can you give me some context?
Like what are some
other examples of cost effectiveness
for some other common screening
modalities like colonoscopy
or mammogram, or like
we were saying earlier, the C-spine
screening for trauma.
What did you have a sense of what
those QALYs are and the willingness
(16:58):
to pay?
Sure. So, yeah, So typically
in the United States, as
you said, it's about 100,000.
I think that varies somewhat
anywhere between 50, 100,000.
And it has not been adjusted
for inflation for some
time. And I think that's a valid
point that in today's day
and age that we should consider
(17:18):
moving the needle on that.
Now, even like some other
countries, when they do these types
of analysis, they may not use that
$100,000 countries
that don't spend as much on health
care as we do.
So I think that's a moving
target depending on
what situation you're in.
(17:39):
Now, to your point about other
cost screening modalities.
So I think one
good example, it's a procedure that
surgeons are familiar with, are
colonoscopies.
So there are studies
out there that compare a ten year
colonoscopy to annual fecal
occult blood testing with annual
sigmoidoscopy.
And if you look there, the
(18:00):
the ICER or the incremental cost
effectiveness ratio anywhere from
30 to 70000.
Now, one important thing about our
study is that we could only take the
analysis out to a one-year horizon.
And a lot of times these studies
will go out to a five-year horizon.
And the reason why we could only do
one year was because we there's no
(18:20):
data on BCVI past one
year. It's just not out there.
So it is you know, it's
entirely possible when you look at
longer term projection for
BCVI, especially when the
complication is as catastrophic
as it can be with a stroke,
the ICER may actually be much lower
(18:40):
than the next most effective
screening strategy, which was
extended number of criteria.
So.
Yeah.
I think we we really need
to take into account
the stakes or the
severity of the complication
when we're considering our
willingness to pay.
(19:01):
And for something as devastating
as a stroke or a spinal cord injury,
for example, in cervical spine
injury.
I think we should be a little bit
more willing.
We should be more willing to accept
a lower cost effectiveness
if the consequences of
saving that money are going to be
devastating for the patient.
(19:23):
Yeah, I agree. And also
other factors to consider is like
age of the patient.
So you have someone
who is younger with a BCVI.
Obviously their their
cost of becoming disabled from
stroke will be much, much
higher. So
there are a lot
of factors to consider when choosing
(19:44):
the most cost effective strategy.
Mm hmm. Now, speaking of cost
effectiveness,
you know the analysis, if I'm
reading the methods it includes
your model included imaging,
initial stroke events, and
the monthly chronic cost of
stroke.
You know, zooming out from the
individual perspective, from a
(20:05):
purely societal cost effective
approach.
It seems like a quick death shortly
after BCVI is very low
cost. Right.
It doesn't generate additional
essentially,
what is it, a competing event?
Right. So so how does
how do cost effectiveness models
like yours treat death as an
(20:25):
outcome? Do they assign them—death,
like, a dollar amount?
Yeah, it's a great question.
So.
So you're absolutely right.
A quick death does not result in
a lot of cost.
However, with your
incremental cost effectiveness
ratio, one thing that it does
factor in into the ratio
(20:46):
is the quality
adjusted life year added.
So although you may not have a
huge cost, you do
not with a quick death, you also
don't have much added quality
life.
So that will affect your ratio.
And I will say in the United States,
(21:06):
usually that death is not quick
and cheap. It's usually
very you know, most
money is spent on
health care at the end of life.
So rarely happens
that way.
Yeah. Yeah.
All right. Well, thank you for
clarifying. That was that was a
burning question I had about this.
All right. So after reading your
(21:27):
paper, this is what I
thought of. This is how I was
thinking about using your
paper moving forward
for my institution, I would like to
begin universal screening
for a period of about one or two
years and identify
our true prevalence of BCVI.
You know, maybe it'll fall between
(21:47):
that 1% to 7%, maybe
it's higher, I don't know.
But depending on what I find
the prevalence of our institution to
be, we will either continue
universal screening or will scale
back to one of those other criteria
Memphis, Denver, or
extended Denver, or maybe
some other variation of Denver.
Since I'm at Denver,
(22:08):
do you agree with this approach?
Yeah, I think that that's a totally
reasonable approach,
you know, And,
you know, there are probably more
than one ways to determine
that. You know, for example, if you
use extended Denver criteria,
we know that that probably misses
anywhere from 14 to 20% in BCVI.
So you could probably extrapolate
(22:29):
some numbers from that.
But I definitely think that what
you are proposing is a
great idea. I mean, that's kind of
what we do in trauma, right, with
with performance improvement
projects. And
it's looking at,
you know, our guidelines or doing
our protocols and
reassessing them to determine if
there's a compliance and if they're
effective and in this case,
(22:51):
cost effective.
Great. Great. Well, thank you for
backing me up on my proposal.
What's next for you?
Where do you take it from here?
What are your follow up studies
plans?
Well, I think, you know, pediatric
BCVI screening is a moving target.
So I think that is
one thing that would be
(23:11):
great to look at in terms of cost
effectiveness, as we kind of talked
about.
You know, the stakes are a lot
higher when patients are younger.
Just in terms of implementation
and coming up with a, you know, what
is exactly universal screening
and how to implement it at different
trauma centers is
kind of another important topic of
(23:31):
study.
Great. Well, thank you.
I really appreciate that you
took the time to describe
to us your your important research
findings and for answering
all of the burning questions that I
had about your
about your study.
I want to thank the listeners.
Thank you for listening to
The Operative Word. Please send us
any feedback to postmaster@facs.org.
(23:57):
thank you for listening to the
Journal of the American College of
Surgeons Operative Word Podcast.
If you've enjoyed today's episode,
spread the word on social media by
using the hashtag
#JACSOperativeWord, subscribe to The
Operative Word wherever podcasts are
available or listen on the American
College of Surgeons website at
(24:18):
facs.org/podcast.
Welcome to the Operative Word,
a podcast brought to you by the
Journal of the American College of
Surgeons.
I'm Dr. Jamie Coleman.
And throughout this series, Dr.
Dante Yeh and I will speak with
recently published authors about the
motivation behind their latest
research and the clinical
implications it has for the
practicing surgeon.
(00:22):
The opinions expressed in this
podcast are those of the
participants and not necessarily
that of the American College of
Surgeons.
Welcome to the Operative Word, a
podcast from the Journal of the
American College of Surgeons.
I'm Dr. Dante Yeh, one of your
co-hosts for the series.
In this episode, we'll be taking an
in-depth look into the current
(00:43):
article, Cost Effectiveness
of Universal Screening for Blunt
Cerebrovascular Injury A
Markov Analysis.
I'm honored to be joined today by a
senior author, Dr. Sharvin Taghavi,
MD, from Tulane University.
Dr. Taghavi, thank you for joining
me today.
Before we begin, do you have any
potential conflicts of interest to
disclose?
I do have some funding from the CDC,
(01:05):
but none of which is relative
to or related to this research
specifically.
Great. Thank you for the disclosure.
Can you give us a brief summary
of your study design and just and
describe to us your main findings?
Sure. So BCVI
is really interesting in that over,
you know, really three decades of
time, the pendulum has
(01:25):
continued to swing and things have
changed and been driven by research.
So one thing that
if you look at the literature
related to this that seems to be
changing now is that a lot of places
are adopting universal screening
where basically pretty much every
trauma patient is getting a CTA,
some exceptions, obviously, and
looking for a blunt cerebrovascular
injury. And a lot of studies have
(01:45):
shown that using some traditional
screening criteria, you're going to
miss anywhere from 10 to 20%
of blunt cerebrovascular injuries.
So as more and more reports of
universal screening have come out,
we wanted to look at how
a universal screening strategy
might affect cost effectiveness
in terms of treating and screening
for BCVI.
(02:06):
So we used Markov decision
model, and a Markov decision model
is basically a mathematical model
that uses probabilities to simulate
future transitions from one disease
state to another.
In this particular case, different
disease states could be a missed
BCVI or a diagnosed BCVI.
And then it kind of models
are based on probabilities two
different transitions relevant
(02:27):
to this study. Those transitions
could be a stroke, it could be
nothing. And, you know, regular
recovery from blunt trauma or
death from stroke.
And in a cost analysis
and a Markov decision model can
compute the relative cost of each
pathway that you go along,
as well as the quality of life
that's accumulated within each
pathway.
(02:47):
It then uses a kind of sophisticated
mathematical analysis to determine
whether a change in treatment, in
this case universal screening
versus different types of screening,
and determine if that's cost
effective using some benchmark
so that the literature has
kind of proven to be
cost effective.
Great. And tell us, what were the
(03:08):
main findings of your Markov
analysis?
Sure. So what we found out was that
universal screening did appear
to be more the most cost
effective method of screening.
And we looked at Denver criteria,
extended Denver criteria, Memphis
criteria, and no screening at
all. And although we know that
pretty much no one at this stage
(03:28):
does, no
screening, we still included
that in the model as a baseline.
And what we found was that universal
screening, when you looked at the
cost of missed BCVI
and the various different pathways
along the decision tree analysis,
universal screening did appear to be
the most cost effective
(03:49):
method of screening.
Now, that came with a couple of
caveats. So, one
of them is how common
BCVI is.
So, prior to,
there was a great study from
one of our coauthors Jonathan Black
out of UAB.
Prior to his study,
the incidence of BCVI was thought
to be between 1 and 3%.
(04:11):
His study showed that actually, with
universal screening, the
incidence of BCVI is actually much
higher. He found it to be
as high as 7%.
So, we found that if the incidence
of BCI falls between 2.6
and 6%,
universal screening is actually,
excuse me, extended Denver criteria
(04:31):
is actually the most most
cost effective screening.
Now if you're incidence ABC
BCB is over 6%,
then universal screening actually
becomes the most
cost-effective method of screening.
Now the second caveat is that
looking at how effective
antithrombotic therapy is and
(04:53):
we used we use antithrombotic
therapy because that's probably the
most common know.
Some sometimes people use a heparin
drip or following anticoagulation,
but we looked at antithrombotic
therapy and so.
Using.
If you look at the Eastern practice
management, Eastern
Association for the Surgery of Traumapractice
(05:13):
management guidelines
in 2020, they did a meta-analysis
looking at the
effectiveness of antithrombotic
therapy after BCVI.
And what they found through the
meta-analysis was that the odds
ratio of stroke was about 0.2%.
So that's the number we kind of used
for the model.
However, when we did a sensitivity
(05:35):
analysis, what we found was that
if the ratio of
antithrombotic therapy after
BCVI for stroke is 0.35
or less, then universal screening
is the most cost effective.
If antithrombotic therapy is not
as effective as we think it is, if
the odds ratio of stroke is above
0.35, the expanded
(05:56):
Denver criteria is the most
cost-effective therapy.
That makes a lot of sense to me.
If the incidence
of the disease
that you're screening for is
higher, then it makes
more sense to screen for it
more vigorously.
And if it's lower, then it's less
cost effective to go looking for
(06:17):
if it's a more rare entity.
And similarly, if the treatment that
you have available to treat
it is less effective,
then it's going to be less cost
effective to diagnose it in the
first place if your treatment is not
even going to work anyway.
Right?
So yeah, that seems to a
that seems to make sense to me
(06:37):
from a from a you know, a
very unsophisticated statistical
understanding. It totally makes
sense.
I want to back up for a second.
You mentioned the expanded Denver
criteria and you
you mentioned that in your model,
you sort of looked at the whole
spectrum of behaviors
ranging all the way from no
screening to universal
(06:58):
screening.
And you mentioned also the Memphis
criteria and the Denver criteria.
And I assume I'm assuming that these
falls somewhere within
that spectrum.
Can you sort of give the readers,
if they're not familiar with these
criteria, can you give us a rough
description of the three different
(07:19):
screening criteria that you entered
into your model?
Sure.
So, yeah, so we modeled with Denver
criteria, extended Denver criteria,
Memphis criteria, all
three kind of named after the
institutions that kind of came
up with the screening strategies.
You know, there are a lot of nuanced
details that make them different.
(07:40):
But in generality, the
Memphis criteria
kind of focuses more on,
you know, cervical spine injury.
So if there's any sort of cervical
spine fracture, as well
as facial fractures such as LeFort
two and LeFort three, when you
move to the Denver criteria,
it's a slightly more inclusive.
(08:01):
I talks about having,
you know, if there are severe
there's a lot of physical findings
that go in to the cervical bruit,
you know, altered mental status with
cervical trauma.
If you have a you know, I
think all of them kind of talk about
having a mental status that's not
consistent with CT
findings. And you want to get a CTA.
The Denver criteria is a little more
(08:22):
inclusive with facial fractures, for
example, it adds on mandibular
fractures and even
significant cervical soft tissue
injuries.
And extended Denver criteria
is even more inclusive and
adds on some things such as
injury mechanisms like a near
hanging clothesline
(08:42):
type injuries.
It kind of specifies,
you know, closed head injuries with
diffuse axonal injury as well.
So with extended Denver
criteria as again,
over a couple of decades as
as you know, research
became better and our
community kind of
(09:02):
increased the data that is
available.
The screening criteria kind of
became more inclusive and added
more criteria to the screen
patients.
It kind of reminds me of
the paradigm shift in cervical
spine fracture screening
where, you know, we were talking for
a while about NEXUS and
Canadian C-spine, and
(09:23):
by the time you get the Canadian C
spine, you're basically doing
universal screening anyway.
So as we find more and more of these
injuries with lower
and lower mechanisms, it seems like
we're expanding our criteria even
more so that we're basically
approaching universal screening.
Yeah, actually, I think that's a
great point because I think as
more and more places adopt universal
(09:45):
screening, we're going to have a ton
of data.
And, you know,
I think that it's going to get even
more nuanced, I guess.
Universal screening is pretty
straightforward, just screening
everybody. But I think that
eventually, as we accumulate more
data, we'll be able to get more
nuanced with our screening.
So I want to take
this moment to ask for some
clarification about what you mean
(10:06):
by a universal screening,
because as trauma surgeons, we
see the tip of the iceberg,
at least at my institution, where
there's a lot of low level traumas
that are evaluated by our
emergency medicine colleagues and
are worked up and then are
never even brought to our attention.
(10:26):
So, you know, in a typical trauma
center, there's, well, how many do
you see in the ED?
How many are admitted?
How many have a injuries severity,
score over 15, etc.?
What do you mean—in your study
how did you define universal
screening? Was there anybody let's
say they got kicked in the stomach
by a horse.
Would that person get universal
(10:46):
screening or do they have to meet
a certain activation level,
like the highest level of, you know,
for example, trauma team activation?
Or do they have to have a certain
energy mechanism?
Can you can you clarify that for me?
Sure. Yeah. And that's a great
question because, you know, it turns
out there's really not an accepted
definition of universal screening.
And I bet if you polled different
institutions and even actually
(11:08):
use a loose universal screening, if
you called the different trauma
surgeons that are taking call at our
trauma center in New Orleans, I bet
you you'll get a slightly different
answer from each one of them.
But, you
know, in general, if you look at
prior, you know, prior
work publications, there are
places that are just doing activated
patients.
So for us, what we're used generally
(11:29):
doing is patients that meet level
one or level two, activation
at our trauma center will
essentially get a CTA.
Now, again, there is some
exceptions to that. As you said, if
there's an isolated injury like a
refrigerator fell on my knee
and that patient's activated because
they got a pulseless foot, but they
didn't have any trauma, they don't
(11:50):
have like a high speed mechanism,
then that patient might not get a
CTA.
The place where I think that
has the opposite, the possibility
where you could be missing is, as
you said, the patients that are
seen by the emergency room staff not
activated.
Maybe a trauma consultation occurs,
maybe not.
But I do think in general, if there
(12:11):
is mechanism there, then
we will generally get a CTA.
Is it safe to say that anybody
who's getting a CT of the C spine
should probably get a CTA under
the universal screening paradigm?
Yeah, I think that's a that's a fair
assessment. I mean, that's that's
kind of the strategy I use.
If, if there's enough trauma to
the head and neck region where I
(12:32):
want to have
a CT head and/or a CT C-spine then Ithink a CTA
neck is warranted.
Got it. Got it.
Oh, so let me
pose the question to you.
So I recently had
a patient who had both
a grade one BCVI
as well as a concomitant severe
(12:52):
traumatic brain injury.
And so we spoke
with our neurosurgical colleagues
and they said, no, no,
antithrombotic therapy, no
anticoagulation for the first
72 hours.
And it's my understanding that
that's when the strokes are most
likely to occur for these
BCVIs, the devastating
ones will occur early.
(13:12):
Do you have an estimate for
what percentage of patients
fall into this category where they
have a known diagnosed
BCVI but a contraindication
to early antithrombotic
therapy?
Yeah. So I don't think there's
any any studies
to kind of answer that specific
question.
(13:33):
What I do know is that most of
the literature that
reports starting antithrombotics,
if you look at the average time to
initiation of antithrombotics is
roughly around 2428
afterwards, I think that a lot of
these patients are actually having
some sort of contrary indication
(13:53):
to starting antithrombotics
early.
That being said, you know, it's a
lot of what we deal with.
You know, you're you're you're stuck
between a rock and a hard place.
You know, the vast majority of these
strokes do happen within 72 hours.
So it is very important to weigh the
risks and benefits of
antithrombotics
and to initiate treatment as
early as possible.
(14:14):
And actually, I think most of the
studies there's no randomized
controlled trial, but most of the
studies show that early
antithrombotics
in TBI are relatively safe
and helped decrease
the risk of stroke. So
I think it's a you know, and
(14:35):
you just kind of have to
use judgment and decide what is best
for the patient.
Sure. Sure. Absolutely.
If I'm reading your methods
correctly, though, your model
assumes that all patients
with a diagnosed BCVI
were treated with antithrombotic
therapy, and obviously the cost
effectiveness of a screening
(14:55):
method will decrease if
one cannot act upon the results
of those screenings.
Right. So what good is it if I
diagnose it, if I can't treat it?
Do you have a sense of at what
threshold of untreated BCVI
is universal screening no
longer cost effective, like 50%?
80%?
(15:15):
Yeah. I mean, I think
it's that's hard to say.
I think if you like, in our
sensitivity analysis,
again, we're you know, we're
assuming some sort of benefit
with antithrombotics.
Obviously, if there is no benefit
because you can't treat, then
your cost effectiveness will
(15:36):
differ.
You know, maybe
we didn't look at the model that
way, but maybe even maybe
even something such as no screening
becomes more cost-effective.
Although I wouldn't advocate for
that.
Yeah, I don't think anybody would.
Yeah, it's a great question.
I just don't know that we have the
(15:56):
answer to it.
Well, hopefully
with more screening and more data,
we'll we'll know that answer in
a couple of years.
Let's shift for a second.
So your incremental
cost effectiveness ratio
approach uses
a familiar willingness to
pay threshold of $100,000
(16:17):
per QALY—and QALY stands
for quality adjusted life years—so
100,000 is a figure
that I've been seeing since the
early days of my medical career,
like 20 years ago.
Surely with inflation,
this value must have changed over
time.
And so I was wondering what
is $100,000 for QALY?
(16:37):
Like what?
Can you give me some context?
Like what are some
other examples of cost effectiveness
for some other common screening
modalities like colonoscopy
or mammogram, or like
we were saying earlier, the C-spine
screening for trauma.
What did you have a sense of what
those QALYs are and the willingness
(16:58):
to pay?
Sure. So, yeah, So typically
in the United States, as
you said, it's about 100,000.
I think that varies somewhat
anywhere between 50, 100,000.
And it has not been adjusted
for inflation for some
time. And I think that's a valid
point that in today's day
and age that we should consider
(17:18):
moving the needle on that.
Now, even like some other
countries, when they do these types
of analysis, they may not use that
$100,000 countries
that don't spend as much on health
care as we do.
So I think that's a moving
target depending on
what situation you're in.
(17:39):
Now, to your point about other
cost screening modalities.
So I think one
good example, it's a procedure that
surgeons are familiar with, are
colonoscopies.
So there are studies
out there that compare a ten year
colonoscopy to annual fecal
occult blood testing with annual
sigmoidoscopy.
And if you look there, the
(18:00):
the ICER or the incremental cost
effectiveness ratio anywhere from
30 to 70000.
Now, one important thing about our
study is that we could only take the
analysis out to a one-year horizon.
And a lot of times these studies
will go out to a five-year horizon.
And the reason why we could only do
one year was because we there's no
(18:20):
data on BCVI past one
year. It's just not out there.
So it is you know, it's
entirely possible when you look at
longer term projection for
BCVI, especially when the
complication is as catastrophic
as it can be with a stroke,
the ICER may actually be much lower
(18:40):
than the next most effective
screening strategy, which was
extended number of criteria.
So.
Yeah.
I think we we really need
to take into account
the stakes or the
severity of the complication
when we're considering our
willingness to pay.
(19:01):
And for something as devastating
as a stroke or a spinal cord injury,
for example, in cervical spine
injury.
I think we should be a little bit
more willing.
We should be more willing to accept
a lower cost effectiveness
if the consequences of
saving that money are going to be
devastating for the patient.
(19:23):
Yeah, I agree. And also
other factors to consider is like
age of the patient.
So you have someone
who is younger with a BCVI.
Obviously their their
cost of becoming disabled from
stroke will be much, much
higher. So
there are a lot
of factors to consider when choosing
(19:44):
the most cost effective strategy.
Mm hmm. Now, speaking of cost
effectiveness,
you know the analysis, if I'm
reading the methods it includes
your model included imaging,
initial stroke events, and
the monthly chronic cost of
stroke.
You know, zooming out from the
individual perspective, from a
(20:05):
purely societal cost effective
approach.
It seems like a quick death shortly
after BCVI is very low
cost. Right.
It doesn't generate additional
essentially,
what is it, a competing event?
Right. So so how does
how do cost effectiveness models
like yours treat death as an
(20:25):
outcome? Do they assign them—death,
like, a dollar amount?
Yeah, it's a great question.
So.
So you're absolutely right.
A quick death does not result in
a lot of cost.
However, with your
incremental cost effectiveness
ratio, one thing that it does
factor in into the ratio
(20:46):
is the quality
adjusted life year added.
So although you may not have a
huge cost, you do
not with a quick death, you also
don't have much added quality
life.
So that will affect your ratio.
And I will say in the United States,
(21:06):
usually that death is not quick
and cheap. It's usually
very you know, most
money is spent on
health care at the end of life.
So rarely happens
that way.
Yeah. Yeah.
All right. Well, thank you for
clarifying. That was that was a
burning question I had about this.
All right. So after reading your
(21:27):
paper, this is what I
thought of. This is how I was
thinking about using your
paper moving forward
for my institution, I would like to
begin universal screening
for a period of about one or two
years and identify
our true prevalence of BCVI.
You know, maybe it'll fall between
(21:47):
that 1% to 7%, maybe
it's higher, I don't know.
But depending on what I find
the prevalence of our institution to
be, we will either continue
universal screening or will scale
back to one of those other criteria
Memphis, Denver, or
extended Denver, or maybe
some other variation of Denver.
Since I'm at Denver,
(22:08):
do you agree with this approach?
Yeah, I think that that's a totally
reasonable approach,
you know, And,
you know, there are probably more
than one ways to determine
that. You know, for example, if you
use extended Denver criteria,
we know that that probably misses
anywhere from 14 to 20% in BCVI.
So you could probably extrapolate
(22:29):
some numbers from that.
But I definitely think that what
you are proposing is a
great idea. I mean, that's kind of
what we do in trauma, right, with
with performance improvement
projects. And
it's looking at,
you know, our guidelines or doing
our protocols and
reassessing them to determine if
there's a compliance and if they're
effective and in this case,
(22:51):
cost effective.
Great. Great. Well, thank you for
backing me up on my proposal.
What's next for you?
Where do you take it from here?
What are your follow up studies
plans?
Well, I think, you know, pediatric
BCVI screening is a moving target.
So I think that is
one thing that would be
(23:11):
great to look at in terms of cost
effectiveness, as we kind of talked
about.
You know, the stakes are a lot
higher when patients are younger.
Just in terms of implementation
and coming up with a, you know, what
is exactly universal screening
and how to implement it at different
trauma centers is
kind of another important topic of
(23:31):
study.
Great. Well, thank you.
I really appreciate that you
took the time to describe
to us your your important research
findings and for answering
all of the burning questions that I
had about your
about your study.
I want to thank the listeners.
Thank you for listening to
The Operative Word. Please send us
any feedback to postmaster@facs.org.
(23:57):
thank you for listening to the
Journal of the American College of
Surgeons Operative Word Podcast.
If you've enjoyed today's episode,
spread the word on social media by
using the hashtag
#JACSOperativeWord, subscribe to The
Operative Word wherever podcasts are
available or listen on the American
College of Surgeons website at
(24:18):
facs.org/podcast.
Popular Podcasts
Dateline NBC
Current and classic episodes, featuring compelling true-crime mysteries, powerful documentaries and in-depth investigations. Follow now to get the latest episodes of Dateline NBC completely free, or subscribe to Dateline Premium for ad-free listening and exclusive bonus content: DatelinePremium.com
24/7 News: The Latest
The latest news in 4 minutes updated every hour, every day.
Therapy Gecko
An unlicensed lizard psychologist travels the universe talking to strangers about absolutely nothing. TO CALL THE GECKO: follow me on https://www.twitch.tv/lyleforever to get a notification for when I am taking calls. I am usually live Mondays, Wednesdays, and Fridays but lately a lot of other times too. I am a gecko.