Transcript Slide 1

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
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.
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
Coronary artery disease is the single most common cause
of death is
in Europe,
accounting for
nearly 2.000.000
a pathogenetic
mechanism
deaths per year.
that is as important as e.g.
Stroke 1 million people / year in Europe
Brainin e.a. Eur J Neurol 2000 7 5-10
the Immune System or
Atrial fibrillation: 4.5 million people in the European
the Regulation
Union, major
risk of stroke of Cell Division
Severe traumatic injury, hemorrhage: > 40% of deaths;
Of which ~75% with coagulopathy: > 4-fold higher mortality,
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.
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…….......
As a haematologist you will have to
admit that clotting times:
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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%)
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
Most colleagues back out
What we should like to have in
thrombotic and bleeding disease:
(Something like blood-glucose in diabetes
or clearance in kidney disease)
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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
Blood clots because THROMBIN generates
But look how it develops when blood clots:
200
Thrombin
(nM)
100
Ca++in Plasma
Clot forms
0
Clotting Time
5
Time (min)
10
15
Plasma clots when < 2% of all thrombin is formed
> 98 % of all thrombin forms explosively in the clot
Todays central and most important issue:
The force of the explosion is more important than
the moment at which it exactly occurs.
What appeared:
The Power of Thrombin,
is the important thing
NotNOT
thethe
Time
that ittime
takes
clotting
before it starts being formed
The power of thrombin =
The “man hours” of thrombin activity =
The area Under the TG-curve =
Endogenous Thrombin Potential (ETP)
The Endogenous Thrombin Potential (ETP)
Holds more important information than the clotting time
Why this is deserves a
separate lecture
0
Clotting time
If thrombin action is so important, then let
us measure thrombin action by adding a
fluorogenic thrombin substrate
thrombin
substrate
Prothrombin
(Plasma)
Thrombin
Inactive Thrombin
fluorescent
product
(Serum)
Thrombin
concentration
0
5
10
Fluorescence
Thrombin
fluorescence
15
Time (min)
Thrombin concentration can be calculated from
the fluorescence measured in a 96-well
fluorometer.
Very Low Tissue Factor
No Heparin
Low Tissue Factor
No Heparin
Very Low Tissue Factor
Heparin
Low Tissue Factor
Heparin
12 experiments can be measured simultaneously
(4 x 3)
Calibrated Automated Thrombinography CAT
Calibrated Automated Thrombinography CAT
Calibrated Automated Thrombinography CAT
Calibrated Automated Thrombinography CAT
Calibrated Automated Thrombinography CAT
Calibrated Automated Thrombinography CAT
Calibrated Automated Thrombinography CAT
Calibrated Automated Thrombinography CAT
The method is operative in ~ 400 labs over the world
Thrombin generation is becoming a ‘hot’ subject.
More and more publications appear each year.
350
300
250
200
150
100
50
0
1980
1985
1990
1995
2000
2005
Year
What has been found ?
2010
The results can be summarised in one simple phrase:
The first law of haemostasis and thrombosis:
The more Thrombin, the less
Bleeding
but the more Thrombosis,
The less Thrombin, the more
Bleeding
but the less Thrombosis
C.H.
A: All congenital and acquired thrombotic tendencies: TG
B: All congenital or acquired bleeding tendencies
C: If
TG
: Thrombotic tendency
D: If
TG
:
Bleeding tendency
Examples :
TG
All congenital and acquired thrombotic tendencies:
TG
Factor V Leiden
+
Hyperprothrombinaemia
No Addition
+TM
+ APC
thrombin (nM)
thrombin (nM)
No Addition
500
500
Normal Control
No Addition
thrombin (nM)
500
Factor V Leiden
+TM
+TM
+ APC
+ APC
0
0
5
10
time (min)
15
20
0
0
0
5
10
15
time (min)
20
0
5
10
15
time (min)
Effect is additive !
20
If
TG
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
: More venous Trombosis
If
TG
: Trombotic Tendency
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
Arterial Trombosis :
TG
Coronary Artery Disease
Acute myocardial infarction (N=60)
*
Stable CAD
(N=35)
Controls (N=15)
* p<0.05) compared to stable CAD
Courtesy of Mojca Stegnar University Medical Centre Ljubljana, Slovenia
Orbe J, et al. Thromb Haemost 2008;99:382
Congenital or acquired bleeding tendencies
TG
All congenital deficiencies causing
ETP < 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 2002;88:576-82.
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
2005;93:475-80
All congenital or acquired bleeding tendencies:
Example:
Factor V deficiencies
Thrombin (nM)
200
control
2%
150
1%
0.5%
100
0%
50
0
0
5
10
15
20
Time (min)
Also for II, VII, X and XI: AlDieri Thr&Haem. 88: 576 (2002)
TG
Therapy for Bleeding:
TG
Thrombin generation after factor VIII infusion in a haemophiliac
400
1 hr
Thrombin (nM)
300
24 hrs
200
60 hrs
100
Baseline
0
10
20
Time (min)
30
Illustration of the first law:
Four Antithrombotics – Four Modes of Action
Oral Anticoagulants diminish
Prothrombin
Aspirin inhibits
Four
Modes
platelets
required
for
Prothrombinase
of Action, One Effect:
Thrombin
Less
Thrombin
Antithrombin
Heparin enhances
DTI and hirudin act directly
Inactive Thrombin
Thrombin (nM)
300
Effect of Oral
Anticoagulation
NP
200
INR 2
INR 3
100
INR 4
INR 5
INR 6
0
0
5
10
15
20
Time (min)
Thrombin generation: effect of heparin
120
Thrombin (nM)
Control
90
0.1 µg/ml
60
0.2 µg/ml
0.3 µg/ml
30
0.4 µg/ml
0
0
clot
•
10
20
Time (min)
Also the modern anticoagulants
400
Thrombin (nM)
Uninhibited
PLasma
Dermatan sulfate
Heparin
Fondoparinox
Melagatran
Otamixaban
0
0
15
30
Time (min)
Otamixaban,,Melagatran,,Heparin,,Dermatan sulfate,,Fondoparinox
45
Summary:
Why Thrombin Generation ?
1:
2:
3:
4:
5:
6:
7:
Predicts thrombosis risk
Monitors ALL antithrombotic treatment
Reflects bleeding risk in haemophilia
Predicts blood loss in surgery (not shown)
Indicates H&T side effects of drugs (pill and others)
Facilitates search for new antithrombotics
Epidemiology / Public Health
In short:
Works where clotting times fail
Haemostasis &Thrombosis is easy to understand
PT, APTT, WBCT, TEG
If only you forget about clotting times
Clotting made easy :
The more thrombin the less bleeding
but the more thrombosis
Thrombosis
The less thrombin the more bleeding
thrombin
Normal
Bleeding
time
but the less thrombosis
Thrombosis Risk
Normal Range
Thrombosis Prevention
Bleeding Risk
> 110 %
84 - 116 %
25 - 60 %
< 20 %
Summary:
The CAT
How Thrombin Generation ?
Calibrated Automated Thrombin Generation
Questions?
[email protected]