Endotheliopathy in COVID-19- associated Coagulopathy

May 28, 2020

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Alfred Lee, MD, PhD

Yale Cancer Center Grand Rounds | May 26, 2020

ID5249

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00:00Uhm, I know a lot of you guys already,
00:03but I'm one of the clinical
00:05hematologist here at the Cancer Center,
00:07and for the last nine years my main
00:09interest have been medical education
00:10and thrombosis or blood clotting.
00:12And then in mid March of this year
00:15Is everybody knows kovid hit and so
00:17early on when the first kovid patient
00:19arrived at Yale New Haven Hospital.
00:21A few of us in the hematology
00:23section were asked to join a multi
00:25disciplinary effort designed to try
00:27to understand in combat the disease,
00:29an one of the more interesting and kind of.
00:32Unexpected features of COVID-19
00:33infection was that there's actually
00:35a huge component of blood clotting,
00:37and this is something that's term
00:39COVID-19 associated Coagulopathy.
00:40So we became interested in the hematology
00:43section and trying to not just manage
00:45this but also understand this,
00:47and so that's what I'm going to be
00:50talking with you all about today.
00:53So again,
00:54this this whole feature of blood
00:55clotting in Kobe 19 infection is
00:58something that's called COVID-19
00:59associated Coagulopathy.
01:00Its abbreviated CAC and at the laboratory
01:03level it's defined by 4 basic things.
01:05So one is that these patients
01:07have an elevated D dimer.
01:09That's often very, very high.
01:10The second is that they have
01:13a high fibrinogen level.
01:14Again, that's often very high.
01:16The third is that many of these patients
01:18have a normal prothrombin time,
01:20or very slightly elevated prothrombin time,
01:22and the 4th.
01:23Is that most of them have normal
01:26platelet counts,
01:27although some of them do have a
01:29slightly reduced platelet count.
01:31And again, as I mentioned before,
01:33clinically the main feature
01:35associated with code 19 associated
01:36Coagulopathy is thrombosis.
01:38So these patients have a very high
01:40risk of developing blood clots,
01:42predominantly venous thromboembolism or VTE,
01:44and in particular pulmonary embolism.
01:46There are some single institution
01:48studies that suggest that up to 37
01:51to even 40% of COVID-19 patients
01:52in an intensive care unit.
01:54Who are ready on prophylactic
01:56anticoagulation will develop a pulmonary
01:59embolism or a deep vein thrombosis.
02:01And In addition Artur thrombosis an
02:04then microvascular thrombosis on
02:06autopsies has also been described.
02:08So because of this very high rate
02:10of thrombosis are hospital system,
02:12our institution was actually one
02:14of the first in the country to
02:16develop what we call an escalated
02:19intensity anticoagulation regiment.
02:20So what I mean by this is that as
02:23most of you who are clinicians know,
02:26whenever patients in general get
02:27admitted to the hospital already there,
02:30blood clotting risk goes up and
02:32so most patients admitted to a
02:34hospital center including Smilow
02:35would be on what we call a low dose
02:39of prophylactic anticoagulation.
02:40Typically,
02:40enoxaparin had a dose of 40
02:42milligrams once a day.
02:43But in kovid patients,
02:45because of this increase risk of
02:47Trumbo Sis we adopted this escalated
02:50intensity anticoagulation regiment
02:51so that patients with Cove in
02:53infection who had a D dimer level
02:55that was above a certain cut off
02:57which we ended up choosing us 5
03:00milligram per liter would
03:01automatically get a higher
03:03dose of anticoagulation.
03:04We would call this intermediate
03:06enoxaparin typically,
03:07which is at a dose of 0.5 milligrams
03:10per kilogram twice a day and then
03:12again because of this super high.
03:14Risk of thrombosis in any covert
03:16patient in whom there is a suspicion for
03:19venous thrombotic event or confirmed
03:21Venus Don Bolic event we would
03:23recommend full dose anticoagulation
03:24typically again with enoxaparin
03:26editors of 1 milligram per kilogram
03:28twice daily so as I mentioned we
03:30were one of the first hospital
03:32centers in the country to develop.
03:35One of these escalated escalated
03:37anticoagulation dosing guidelines
03:38and many other hospitals if not most
03:40around the country have followed suit.
03:42One of the challenges that
03:44we've all had his clinicians.
03:45Is that even though most of us
03:47in the country are doing these
03:49escalated anticoagulation regiments,
03:50we don't actually know if they're safe
03:52or if there even affective and so at
03:54yell our group is in the process of
03:56analyzing this now as are many others
03:58and there are some clinical trials
04:00around different institutions in the
04:01country that are looking at this issue.
04:03This question as well.
04:06So one of the early studies that
04:07came out from China on covert
04:09associated Coagulopathy reported that
04:11it was essentially a variation of
04:14disseminated intravascular coagulations,
04:16or DIC,
04:16which as most of you all know as sort
04:19of an end point of a coagulopathic
04:21picture that's characterized by
04:23pretty high rates of thrombosis
04:26and terminal disease.
04:27But DIC itself again as a
04:29lot of other clinicians know,
04:31has a very characteristic laboratory pattern,
04:34and to us it really didn't seem.
04:36White covered associated Coagulopathy
04:38was similar to DIC at all.
04:41So early on when we start first started
04:44seeing kovid patients in our hospital,
04:46we decided to do a couple of studies
04:48to try to understand what the
04:50code associated Coagulopathy is.
04:52And so this first study that we did
04:54was led by one of our star first
04:57Hematology Fellows George Joshua,
04:58and what we did here was to look at
05:01the 1st 200 plus patients with Kobe,
05:04who are admitted to our hospital and
05:06we calculated what's called a dic
05:08score at specified by the International
05:10Society of thrombosis and hemostasis,
05:12or IST age.
05:12And so the way this works is that
05:14the ice TH score essentially looks
05:17at different laboratory features of
05:19patients suspected of having DIC,
05:21and then it spits out a score.
05:23And if your score is in the range
05:25of five and up,
05:26then that's considered overt DIC
05:28in anything less than five is
05:30not consistent with over DSD.
05:31And so in our first couple 100 patients
05:34with Cobain infection admitted to Yale,
05:36New Haven Hospital when we
05:37calculated the IST FDIC scores,
05:39whether we were looking at patients who
05:41survived or patients who did not survive.
05:43As you can see,
05:44almost all patients had a very low
05:47IST HDC score in this entire group.
05:49There was only one patient who
05:50had an IST HD
05:52score of six consistent with over DIC,
05:54but this is a patient who had
05:56helped syndrome after pregnancy,
05:57and we didn't think that this is
06:00related at all to COVID-19 infection.
06:02So based on this,
06:03we really started to feel that
06:05kovid associated Coagulopathy
06:06was not consistent with DIC,
06:09and so the next thing that we did
06:11was to perform a somewhat large
06:13study of a number of ICU and
06:16non ICU patients with Cove it,
06:19in which we measured lots and lots of
06:21different coagulations factors trying
06:23to see what exactly the mechanism of
06:25covert Coagulopathy might be an weather.
06:28Again this was distinct from DC.
06:31So this work here was carried
06:32out by four people who are shown
06:34at the bottom of the page.
06:36Parveen,
06:36but hell is one of the lab
06:38technicians in the Park Street Lab
06:40who did all of the quag elation
06:42testing and then George Joshua
06:43refers to your fellow Alex Pine,
06:45one of our star senior 30 or
06:47Fellows in he monk and then a
06:49super MD PhD student at my slash
06:52also together did this analysis.
06:53So first I'll starting at the
06:55top of the page.
06:57The first thing we measured were D dimer
06:59levels and something else called a thrombin,
07:01antithrombin complex or TI-80.
07:02So as most of you know,
07:04the D dimer level is something that tends
07:07to go up on patients form blood clots,
07:09and it can often be a very
07:11useful measure of blood clotting,
07:13and one of the significant features of
07:15the D dimer is that encoded infection.
07:17the D dimer level seems to be
07:19one of the very very prominent
07:21markers of mortality and overall
07:23course clinical cores and so.
07:25It's a very useful and important
07:27marker in covert patients,
07:28both for thrombosis and also
07:30for their overall disease cores,
07:31and then thrombin,
07:33antithrombin complexes you can
07:34think of those as sort of a fancy
07:37and more specific D dimer that
07:38really looks at whether AD dimer
07:40elevation comes from activation
07:42of the Quag Elation Cascade.
07:44So when we measured D dimer
07:45levels an from an anti thrombin
07:47complex is both in ICU and non ICU
07:50patients with colon infection.
07:52We found that both of these were elevated,
07:54particularly in patients.
07:55We were in the ICU and on a separate
07:58analysis we found that the D dimer
08:00levels and from an anti thrombin
08:02complex is correlated together.
08:03So this let us know that the source
08:06of the high D dimer encoded associated
08:09Coagulopathy is indeed activation
08:10of the Quag Elation Cascade.
08:13The next thing we did was to measure a
08:15number of endogenous anticoagulants,
08:17antithrombin, protein C, and protein S,
08:19as well as a fire analytic enzyme
08:22called A2 Antiplasmin.
08:23So what are all of these?
08:25Whenever you form,
08:26activate coagulations through
08:27the coagulation cascade,
08:28the body has a natural mechanism to
08:30shut off Coagulations and therefore
08:32prevent from boces from getting
08:34out of control and so that natural
08:36mechanism happens through two sources.
08:38One is through endogenous
08:39anticoagulants that are designed to turn
08:41off the Coagulations Cascade,
08:43and those are these first three up.
08:45Top antithrombin protein protein S
08:47and then the 2nd way that the body
08:50regulates the Quag elation cascade
08:52is to turn on fiber analysis or the
08:54process of digesting blood clots that
08:56are formed and the principal enzyme that
08:59does this is called A2 Antiplasmin.
09:01So as you can see here,
09:03when we measured in documents anticoagulants,
09:05antithrombin protein protein S in ICU and
09:07non ICU patients with colon infection,
09:10we found that they were basically on normal.
09:12Normal is usually anything about
09:1480% and as you can see.
09:16All of these patients had essentially
09:18antis arm approaching CN Protein
09:20S levels around 100%,
09:22indicating that there was not excessive
09:24consumption of anticoagulants.
09:25Endogenous Lee and then we also
09:27looked at A2 Antiplasmin.
09:29The main fibrinolytic enzyme
09:30that I just mentioned,
09:32and again here you can
09:34see the levels in both.
09:35I see you in an ICU patients with
09:38colon infection were normal,
09:40so this let us know that when we
09:42looked at endogenous anticoagulant
09:43San fibrinolytic enzymes,
09:45we were not seeing consumption.
09:47Of any of these,
09:48and the important feature here
09:50is that in most patients with
09:52DIC you should see consumption
09:54of endogenous anticoagulant.
09:55An fibrinolytic enzymes.
09:57So the fact that we were not seeing that.
10:00Let us know that CAC is probably
10:04mechanistically distinct from DC.
10:05The next thing we did was to
10:07measure an enzyme called plasminogen
10:09activator inhibitor or Pai one.
10:11This is the main negative regulator
10:14of fiber analysis and what we
10:16found was that this was elevated
10:18both in ICU and non ICU patients.
10:20The significance of this is that
10:22whenever we see this elevated it
10:24sometimes will suggest that fiber
10:27analysis is inhibited and so it
10:29makes us wonder when we see this
10:31weather perhaps encoded associated
10:32Coagulopathy there may be an inhibition
10:35of Clock breakdown which might
10:37contribute to overall thrombosis risk.
10:39And then the last thing we
10:41did was at the very bottom.
10:44Here we measured three tests,
10:46von Willebrands Factor,
10:47Antigen von Willebrands factor activity
10:49and factor 8 coagulations level.
10:51So what are these fun Willebrand factor?
10:53Is a hemostatic factor that's
10:55released by endothelial cells and
10:57the purpose in coagulations of fun.
10:59Willebrand factor is basically to
11:01help platelets bind to sites of
11:03damaged endothelium and initiate
11:05primary hemostat stasis,
11:06which is important for blood
11:08clotting factor 8.
11:09Separately is a coagulations factor that.
11:12Wines to von Willebrand factor in
11:14the circulation and So what we
11:17notice when we measured levels of
11:19an willebrand factor in factor 8
11:21both in ICU and in ICU patients,
11:23we saw that the levels were quite high,
11:26and in particular the levels were
11:28super elevated in ICU patients,
11:30and I just want to show you another
11:33curve here.
11:34This right here are DOT plots
11:36showing Refactor Antigen one factor
11:38activity and factor 8 in ICU versus
11:40non ICU patients with the green.
11:43Rose indicating what the
11:44normal ranges should be,
11:45so again based on this,
11:47as you can see, one will benefactor in
11:49factor 8 levels are elevated both in
11:52ICU and non ICU patients with Cove it,
11:54but there are through the roof high,
11:56particularly for von Willebrands
11:58factor in the ICU patients.
11:59The significance here is that the major
12:01source of on lower end factor in the
12:04body as it circulates through the blood
12:06is endothelial cells and so whenever
12:08we see this sort of pattern where
12:10we have very very high levels of fun
12:12willebrand factor circulating in the blood.
12:15It tends to point towards a
12:17pattern of endothelial injury.
12:18In addition, von Willebrands factor
12:20can also be stored in platelets,
12:22and so looking at this pattern,
12:25it made us wonder if perhaps both
12:27endothelial cells and platelets
12:28were being hyper activated in
12:30the setting of coded infection.
12:32Particularly as patients
12:34progressed to critical illness.
12:36So in order to test this,
12:38we were interested in looking at specific
12:41markers of endothelial function and
12:43platelet activation and so for this,
12:45we collaborated with Doctor
12:46Hengchun who's an investigator
12:48in the Cardiology Section who,
12:50along with his two postdocs,
12:51doctor home Chang and doctor,
12:53honey and Zhang performed a series
12:55of experiments on all of our ICU and
12:58non ICU patients looking at different
13:00endothelial and platelet activation
13:02markers and the specific ones we
13:04looked at were soluble key selecting.
13:06Which is shown up in the top left,
13:08which is a marker of both
13:10endothelial cells and platelets.
13:11And then we also looked
13:13at soluble CD 40 ligand,
13:14which is seen which is released
13:16by platelets and lymphocytes.
13:17And then Lastly we looked at soluble
13:19from a module in which is specific
13:21mostly to endothelial cells.
13:23Come here because these are
13:24all research tests.
13:25They don't have normal reference
13:27range is so as a result we also got
13:30blood from 13 different control
13:32patients or control individuals,
13:33many of whom are listening
13:35to this talk right now.
13:37So the significance of this is that
13:39when we looked at all these three
13:41different markers of endothelial cell
13:43plus or minus platelet activation,
13:45we saw in pretty much every single case
13:48that the levels were higher in ICU
13:51patients with kovid than they were.
13:53Then controls in the case of
13:55soluble thrombomodulin.
13:56We did not see a significant change in
13:58the level of soluble thermal modeling.
14:01ICU versus control patients.
14:02But what we did notice was that
14:05there were several patients in the
14:07ICU group who had a quite high level
14:09of soluble thermal module in that
14:11made us think that perhaps there
14:13was something going on with soluble
14:16thermal modeling and therefore
14:17endothelial cells that might be
14:19specific to ICU patients.
14:21And so when we did a series of
14:23tests looking at all these different
14:25markers and comparing to mortality,
14:27we found that interesting Lee soluble
14:29thrombomodulin level segregated
14:30with mortality.
14:31Whether we looked at the entire
14:34population in our cohort or
14:36whether we looked at ICU patients.
14:38Alright, so putting this altogether,
14:40what did we learn from from these studies?
14:44First in measuring different
14:45levels of endogenous anticoagulant
14:47sand fibrinolytic enzymes,
14:48we found that antithrombin protein to
14:50protein S and A2 anti plasm overall
14:53preserved which is distinct from DIC
14:55indicating that indeed code associated
14:57Coagulopathy is not the same as DIC.
15:00We also learned that Pai one is elevated,
15:03encoded associated Coagulopathy suggesting
15:05that fiber analysis might be inhibited.
15:07Although we haven't
15:09completely confirmed that.
15:10In addition,
15:11we saw that on Willebrand factor,
15:13in factory levels, which are markers,
15:15particularly endothelial cells and platelets,
15:17are elevated in both non
15:18ICU and ICU patients,
15:20and in particular are through
15:21the roof high in ICU patients,
15:24suggesting that there is a significant
15:25component of any Philly Opathy and
15:28platelet activation encoding infection,
15:29particularly as patients
15:31become critically ill.
15:32And then Lastly,
15:33we saw that when we measured
15:35specific markers of endothelial
15:36cell and platelet activation,
15:38we found that these were elevated in ICU
15:40patients with soluble thrombomodulin,
15:42which is quite specific for endothelial
15:45function segregating with mortality.
15:47So In conclusion,
15:48what we believe our data shows is
15:50that code associated Coagulopathy is
15:52actually an Endo Philly Opathy where
15:54you see augmented von Willebrands
15:57factor release platelet activation an
15:59hypercoagulability all coming together
16:00causing an increased risk of thrombosis,
16:03including Venus thromboembolism,
16:04Artur thrombosis and also
16:06microvascular thrombus.
16:06In addition,
16:07we think that endothelial
16:09dysfunction or injury is a marker
16:11of progression of critical illness,
16:13encoded 19 infection and we find
16:15that soluble from a modeling as
16:17a specific endothelial marker
16:19seems to segregate with mortality.
16:22Um,
16:22the importance of all of this is that
16:24it's made us wonder if there might
16:26be a role for adding antiplatelet
16:29or even endothelial cell modifying
16:31therapy to our anticoagulation algorithm.
16:33And so early on while we were
16:35developing this story,
16:36we met with a number of the ICU directores,
16:39FDA only Haven Hospital Ann through
16:41a lot of discussion just I think
16:44last week or the week before aspirin
16:46was finally added to our treatment
16:48algorithm and now every patient
16:50who gets admitted to the hospital.
16:52In the ICU with colon infection,
16:54get started on aspirin empirically.
16:58So I just want to acknowledge a lot of
17:00people who contributed to this work.
17:02We have this gigantic,
17:04an amazing hematology team,
17:05both on the research side.
17:06In the clinical side,
17:07on the left are all the trainees
17:09who are working with this.
17:11George and Alex are start fellows in
17:13a particular alot of our discussions.
17:15In fact pretty much every experiment
17:17that we've done really started with
17:19conversations at George and I had many
17:21months ago leading to what we have now.
17:23Matt, my salati as I mentioned,
17:25is a superb PhD student Eric Chang
17:26and Yu Shen Lu are both third year
17:29senior medical residents who are going
17:31to be our fellows this coming July.
17:33And then Rebecca fine is an intern
17:35who expressed some interest in doing
17:38immunology Hematology Research.
17:39Down at the bottom are the members of
17:42Doctor Chung's lab who contributed this
17:44worth hung Chang and honey Jang where
17:46both postdocs as I mentioned in the middle.
17:49We have a number of pharmacists,
17:51some of them are familiar to you
17:52guys who are part of our greater team
17:55looking at anticoagulation outcomes.
17:57Cajun mean Nick Difilippo,
17:58Dana McManus, Cantou Enedina frozen.
18:00Uhm and then over on the right.
18:03Here we have our amazing, outpatient,
18:06benign hematology clinical team.
18:07Audrey Gina, Andrea,
18:09Joy, Ann and hope.
18:11Uhm, and then finally the bottom.
18:12I just want to acknowledge Bob Bono,
18:14who's our new chief of benign
18:15team and then Stephanie Helene's,
18:16our section chief as both of them have been
18:18incredibly supportive of these efforts.
18:20So thank you guys and thank you
18:23Charlie. Thank you and congratulations
18:25to you and really the entire
18:27team on working through this.
18:29Uh, in a very short amount of time
18:32and frankly making a difference
18:34for our patients in the process.
18:36and I know we have some
18:38questions coming through,
18:40but let me start by asking you.
18:42Your research seems certainly indicates that
18:44this is a process of interfere with damage.
18:48And do we? What do we know about the
18:51virus itself that lends support that?
18:53This would be a primary incident
18:56to the endothelium.
18:58Yeah, that's a great question,
19:00so there does seem to be in autopsy studies.
19:03A certain component of endothelial leitis,
19:06which some people have shown might be
19:08related to direct viral infection.
19:10So there have been autopsy studies
19:12that have demonstrated viral
19:14particles within endothelial cells.
19:16Not every study has demonstrated that,
19:18but some people do believe that that is
19:21part of the incipient process that begins
19:24the end of filial pattern of injury.
19:27One of the challenges is that.
19:29A lot of people tend to think
19:31of thrombosis as somewhat later
19:32event occuring clinically,
19:34so it's not clear if there may be a
19:37second sort of hit to the end of Filium,
19:39particularly,
19:40patients become critically ill that
19:41might be independent of viral infection.
19:43It might instead involve inflammation
19:45and other things like compliment that
19:47might trigger and a filial activation.
19:50Thank you other questions
19:52that have come through.
19:53Do you have any information about
19:56the specificity of these changes
19:58for chobit relative to other
20:00respiratory viral infections?
20:01For instance, are microvascular thrombi
20:03a finding in in other respiratory
20:05viral infections beyond coated?
20:07Yeah, that's
20:08a good question to my knowledge I I'm
20:11not aware of a lot of other viruses
20:15that show microvascular thrown by.
20:17There are certain cases of influenza
20:19that can be characterized by
20:21massive inflammatory responses.
20:23Um dangi infection is also often
20:25brought up as an example of a
20:27virus that can cause a pretty
20:29awful coagulopathic picture,
20:31so I'm not sure if any of either of those
20:33in particular are classically associated.
20:36Microvascular phone by or not,
20:38but I'm not aware of a lot
20:40of other viruses that are.
20:43And then another question do that?
20:46Does the Coagulopathy correlate
20:48with the static on storm? Yeah,
20:51so that's a great question Stewart.
20:54So one of the interesting experiments
20:56that that Young Chun started to
20:59do with our patient samples is to
21:01examine different proteomic profiles,
21:04and so we're starting to
21:06get that data back now,
21:08and the hope is to see mechanistically,
21:12if any of the changes inside a current
21:15profiles that that are shown do correlate
21:18with robotic risk or endothelial dysfunction.
21:21One of the challenges we have in
21:23trying to interpret our data fully
21:25is that as most of you guys know,
21:27pretty much every critically ill patient
21:29in the hospital with kovid receives
21:31totalism AB before they reach the ICU,
21:33which is an interleukin six receptor blocker,
21:36and so there may be some effects of
21:38Totalism app not only on Coagulopathy
21:40but also on the sideline profile,
21:42and so we're trying to figure
21:44out how to interpret that.
21:47Another question for patients on on a
21:49ventilator for other causes of a RDS,
21:51do they have elevated levels
21:53of one willebrand factor? Yeah,
21:55even that's a fantastic question,
21:57and so the answer is yes, sort of,
21:59but not not quite to the same level.
22:02So in the literature there's a lot of other.
22:05There's a few other diseases that are known
22:08to have very bad end of Philly Opathy,
22:10one of them being severe DIC
22:13with septic shock and VOD or SOS
22:15in transplant is another one.
22:17Um, and in fact a RDS is known
22:19to also be characterized by NFL
22:21dysfunction as somewhat of a control.
22:23We separately worked with the ICU to
22:26measure von Willebrand factor levels
22:28in non kovid ICU patients who are into
22:30baited and in those patients we did
22:33see elevated von Willebrands levels,
22:34but we did not see a consistently
22:37super high level of unrelated factor
22:39like we do in code and so we do
22:42think there's some specificity to
22:43this particular Cove in response.
22:46Makes sense since the last question
22:48from Stuart is you compared ICU
22:51versus non ICU versus controls?
22:53What about these values in comparing
22:56patients with thrombotic complications?
22:57For those without cloths,
22:59yes Sir, that's a fantastic question.
23:01You know, one of the challenges
23:03that we have at our hospital,
23:05and this is not unique to us,
23:08is that because of concerns about
23:10excess health care worker exposure,
23:12it's not been routine for
23:14covert patients at Yale.
23:16New Haven Hospital to get
23:17imaging to confirm thrombosis.
23:19If you guys recall in the Cove
23:22at anticoagulation algorithm,
23:23we said anybody.
23:23Any patient in whom one suspects a Venus
23:26Roman Bolic event should automatically
23:28start photos anticoagulation.
23:29The reason we added that in there is
23:31because most patients are not getting
23:33imaging to tell whether they really
23:35have a Venus thromboembolic event.
23:36Therefore we don't really have a
23:38good idea of how many patients in
23:40our own hospital system and which
23:42ones actually have a thrombotic
23:43complication and which ones don't,
23:45so I can't answer that based on our data.