Clotting made easy

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Clotting made easy

• The contribution of thrombin generation to the
  understanding and diagnosis of thrombotic and
  haemorrhagic disease

H.C.Hemker S.Béguin R.Wagenvoord R.AlDieri
P.W.Hemker and others
Cardiovascular Research Institute Maastricht The
Netherlands
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You are an MD so you will encounter a bleeding or
a thrombosis problem at least once a week (unless
you are a psychiatrist)
And if you are a geriatrist, surgeon,
orthopedist, internist etc. you will encounter
bleeding or thrombosis problems every day.
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Clinical importance of haemostasis and thrombosis

• Venous thrombosis causes over 500 000 deaths in
  Europe every year, that is more than due to
  breast cancer, AIDS, and traffic accidents
  combined

Thrombosis / Haemostasis is a pathogenetic
mechanism that is as important as e.g. the
Immune System or the Regulation of Cell Division
Coronary artery disease is the single most common
cause of death in Europe, accounting for nearly
2.000.000 deaths per year.
Stroke 1 million people / year in Europe Brainin
e.a. Eur J Neurol 2000 7 5-10
Atrial fibrillation 4.5 million people in the
European Union, major risk of stroke
Severe traumatic injury, hemorrhage gt 40 of
deaths Of which 75 with coagulopathy gt
4-fold higher mortality,
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You are an MD so you learned that the clotting
system is tested by measuring clotting times
You also learned that the prothrombin time
indicates oral anticoagulation and liver function
and the aPTT heparin treatment and hemophilia.
And you know that there is a lot more to be said
which is known by haematologists and which is as
complicated as brain anatomy and such
hyperspecialistic knowledge.
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But you in this audience are haematologist so
they ask you
Why APTT for heparin and PT for OAC?
Why does a normal APTT not exclude perioperative
bleeding risk?
My patient with cirrhosis has a long PT but does
not bleed
Why is the APTT normal in my patient with
thrombosis ?
Why is the pill a risk for thrombosis without
influence on clotting times ?
Etc.etc.etc.......
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As a haematologist you will have to admit that
clotting times

• Need different types for different purposes
• Do not detect a thrombotic tendency
• Do not detect mild bleeding tendency
• Are not proportional to clinical risks
• Do not detect platelet problems

(And that a bleeding time is hardly useful Its
coefficient of variation being 35)
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And as soon as we start explaining
Fibrinogen, Prothrombin, factor V, factorX,
factorIX, factorVII, Contact activation,
Phospholipids, Platelets, AntithrombinIII,
ProteinS, Protein C, Hageman factor, FactorXI,
Extrinsic System, Intrinsic System,
FactorVII,TissueFactor, TM, TFPI
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Most colleagues back out
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What we should like to have in thrombotic and
bleeding disease
(Something like blood-glucose in diabetesor
clearance in kidney disease)

• A defined normal range
• Thrombosis risk when too big
• Bleeding risk when too small
• Danger proportional to value found
• Showing effect of antithrombotic therapy
• Showing effect of substitution therapy
• Easy and precise

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Blood clots because THROMBIN generates
But look how it develops when blood clots
200
Thrombin (nM)
Cain Plasma
100
0
5
10
15
Time (min)
Plasma clots when lt 2 of all thrombin is formed
gt 98 of all thrombin forms explosively in the
clot
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Todays central and most important issue

• The force of the explosion is more important than
  
• the moment at which it exactly occurs.

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What appeared
The Power of Thrombin, is the important
thing Not the Time that it takes before it
starts being formed
NOT the clotting time
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The power of thrombin The man hours of
thrombin activity The area Under the TG-curve
Endogenous Thrombin Potential (ETP)
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The Endogenous Thrombin Potential (ETP) Holds
more important information than the clotting time
Why this is deserves a separate lecture
0
Clotting time
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If thrombin action is so important, then let us
measure thrombin action by adding a fluorogenic
thrombin substrate
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Thrombin concentration can be calculated from the
fluorescence measured in a 96-well fluorometer.
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Very Low Tissue Factor No Heparin
Low Tissue Factor No Heparin
Low Tissue Factor Heparin
Very Low Tissue Factor Heparin
12 experiments can be measured simultaneously (4
x 3)
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Calibrated Automated Thrombinography CAT
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Calibrated Automated Thrombinography CAT
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Calibrated Automated Thrombinography CAT
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Calibrated Automated Thrombinography CAT
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Calibrated Automated Thrombinography CAT
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Calibrated Automated Thrombinography CAT
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Calibrated Automated Thrombinography CAT
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Calibrated Automated Thrombinography CAT
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After the run an analysis program calculates mean
curves and parameters
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Notably the Endogenous Thrombin Potential (ETP)
The method is operative in 400 labs over the
world
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Thrombin generation is becoming a hot
subject. More and more publications appear each
year.
What has been found ?
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The results can be summarised in one simple
phrase
The first law of haemostasis and thrombosis
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Examples
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Factor V Leiden Hyperprothrombinaemia
Factor V Leiden
Normal Control
Effect is additive !
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• Retrospective
• Dargaud 2006
• Brandts 2007
• Van Hylckama 2007
• Tripodi 2007
• Ten Cate-Hoek 2008
• Wichers 2009
• Prospective
• Hron 2006
• Eichinger 2008
• Besser 2008
• Tripodi 2008
• Lutsey 2009

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Recurrence in persons with TG above normal mean
Recurrence in persons with TG below normal mean
Recurrence of idiopathic venous thrombosis, No
Therapy
From  Identification of Patients at low risk of
recurrent venous embolism by measuring thrombin
generation  Hron, Kollars, Binder, Eichinger,
Kyrle. JAMA July 2006 vol 296 p. 397-402
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Coronary Artery Disease

plt0.05) compared to stable CAD
Courtesy of Mojca Stegnar University Medical
Centre Ljubljana, Slovenia
Orbe J, et al. Thromb Haemost 200899382
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All congenital deficiencies causing ETP lt 20
have a bleeding tendency (Factors
II,V,VII,VIII,IX,X,XII)

• Al Dieri R, Peyvandi F, Santagostino E, Giansily
  M, Mannucci PM, Schved JF, Béguin S, Hemker HC.
  The thrombogram in rare inherited coagulation
  disorders its relation to clinical bleeding.
  Thromb Haemost 200288576-82.
• Dargaud Y, Béguin S, Lienhart A, Al Dieri R,
  Trzeciak C, Bordet JC, Hemker HC, Negrier C.
  Evaluation of thrombin generating capacity in
  plasma from patients with haemophilia A and B.
  Thromb Haemost 200593475-80

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Example Factor V deficiencies
Also for II, VII, X and XI AlDieri ThrHaem. 88
576 (2002)
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Thrombin generation after factor VIII infusion in
a haemophiliac
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Illustration of the first law
Four Antithrombotics Four Modes of Action
Oral Anticoagulants diminish
Prothrombin
Four Modes of Action, One Effect Less Thrombin
Aspirin inhibits platelets required for
Prothrombinase
Thrombin
Antithrombin
DTI and hirudin act directly
Inactive Thrombin
Heparin enhances
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Effect of Oral Anticoagulation
300
200
Thrombin (nM)
100
0
0
5
10
15
20
Time (min)
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Thrombin generation effect of heparin
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Also the modern anticoagulants
Uninhibited PLasma
Dermatan sulfate
Heparin
Fondoparinox
Melagatran
Otamixaban
Otamixaban,,Melagatran,,Heparin,,Dermatan
sulfate,,Fondoparinox
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1 Predicts thrombosis risk2 Monitors ALL
antithrombotic treatment 3 Reflects bleeding
risk in haemophilia4 Predicts blood loss in
surgery (not shown) 5 Indicates HT side
effects of drugs (pill and others) 6
Facilitates search for new antithrombotics
7 Epidemiology / Public Health
Summary Why Thrombin Generation ?
In short Works where clotting times fail
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Haemostasis Thrombosis is easy to understand
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Clotting made easy
The more thrombin the less bleeding but
the more thrombosis The less thrombin the more
bleeding but the less thrombosis
Thrombosis Risk gt 110 Normal Range 84 - 116
Thrombosis Prevention 25 - 60 Bleeding
Risk lt 20
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The CAT
Summary How Thrombin Generation ?
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Questions? HC.Hemker_at_Thrombin.Com