Basic Clinician Training Module 2 TEG ® Technology

Basic Clinician TrainingModule 2

TEG® Technology

Hemostasis monitoringRoutine coagulation tests: PT, aPTT

• Based on cascade model of coagulation Measure coagulation factors interaction in solution

(plasma) Determine if adequate levels of coagulation factors

are present for clot formation

• Do not reflect the roles of cells or contributions of local vascular and tissue conditions Plasma-based assays miss the impact of platelets and

platelet activation on thrombin generation. Plasma-based assays use static endpoints (e.g. fibrin

formation) - miss impact of altered thrombin generation on platelet function and clot structure.

Hemostasis monitoringTEG analysis system

• Whole blood test• Measures all phases of hemostasis: initiation through lysis• Shows the net effect of hemostatic components on blood clotting process

The TEG analyzerDescription• TEG: point of care (POC) whole blood

coagulation monitoring device Time to initial results: 4-8 minutes Time to completion (clot lysis): 45-60 minutes

• Uses activated blood to maximize thrombin generation and platelet activation in an in vitro environment Measures the hemostatic potential of the blood at

a given point in time under optimal conditions of thrombin generation

• Demonstrates the contributions and interactions of hemostatic components during the clotting process.

TEG technologyHow it works

TEG sample preparation

• Blood samples can be “modified” by adding agents to the sample

• Activator – maximizes thrombin generation and speeds up clotting time Kaolin – activates intrinsic pathway, used for

normal TEG analysis Tissue factor – specifically activates extrinsic

pathway• Heparinase – removes heparin from sample,

allows view of the underlying hemostatic status of a patient on heparin.

• Platelet activators – allows testing antiplatelet agent responsiveness and efficacy. (Module 7)

TEG sample types

• Kaolin – used for normal TEG analysis• Kaolin with heparinase – used for normal

TEG analysis when patient on heparin Compared with Kaolin-only sample (run

simultaneously) to determine reversal of heparin

Utility of the TEG

• Demonstrates all phases of hemostasis Initial fibrin formation Fibrin-platelet plug construction Clot lysis

• Identifies a balance or imbalance in the hemostatic system – between the clot forming and clot breakdown pathways Identifies likely cause(s) of bleeding Identifies likely cause(s) of thrombosis

What TEG analysis capturesTime

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TEG parameters

Identification

Definition

Thrombin formationThe R parameter - identified

Pin is stationary

Pin is engaged

Intrinsic,extrinsic,commonpathways

Initial fibrinformation

Cup rotates, pin remains stationary

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Pin starts to rotate with cup

FibrinogenThe (angle) parameter - identified

Fibrinincreases

Amplitude of pin rotation increases as fibrin is generatedand cross links are formed

Pin isengaged

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Platelet functionThe MA parameter - identified

Maximum amplitude (MA) of pin rotation

Amplitude of pin rotation

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Platelet functionThe MA parameter - defined

Amplitude of pin rotation

• Amplitude of pin rotation depends on clot strength• Clot strength = 80% platelets + 20% fibrinogen• Platelet function influences thrombin generation and

fibrin formation relationship between R, , and MA

Maximum amplitude (MA) of pin rotation

Coagulation indexThe CI parameter - defined

• Linear combination of kinetic parameters of clot development and clot strength (R, K, angle, MA)

• Provides a global index of hemostatic status CI < -3.0: hypocoagulable CI > +3.0: hypercoagulable

FibrinolysisThe LY30 parameter - identified

Decrease in amplitude of pin rotation30 minutes after MA reached

Time

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30 min

MA

FibrinolysisThe LY30 parameter - defined

• Reduction in amplitude of pin rotation depends on extent of fibrinolysis

Decrease in amplitude of pin rotation30 minutes after MA reached

30 min

MA

TEG parameter summaryDefinitionsR Latency from the time that the blood was placed in the TEG® analyzer

until the initial fibrin formation.

K Measures the rapidity (kinetics) of fibrin build-up and cross-linking, that is, the speed of clot strengthening.

MA Maximum dynamic properties of fibrin and platelet bonding via GPIIb/IIIa; represents platelet function

G Derived from MA, represents the ultimate strength of the fibrin clot

CI Coagulation Index is linear combination of the above parameters.

LY30 LY30 measures the rate of amplitude reduction 30 minutes after MA. This measurement gives an indication of the stability of the clot.

TEG parameter summaryTime

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What does TEG report?

Clotting time

Clot kinetics

Clot strength

Platelet function

Clot stability Clot breakdown

“Normal” TEG tracingTime

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30 min

Hemorrhagic TEG tracing

30 min

Prothrombotic TEG tracing

30 min

Fibrinolytic TEG tracing

30 min

Normal range

Actual value

Components of the TEG tracingExample: R

ParameterUnitsValueNormal range

TEG decision treeQualitative

TEG decision treeQuantitative

US Patent 6,787,363

Hemorrhagic

Thrombotic

Fibrinolytic

TEG tracingExample: hemorrhagic

**

**

TEG tracingExample: prothrombotic

*

* *

*

TEG tracingExample: fibrinolytic

**

Summary

• TEG technology measures the complex balance between hemorrhagic and thrombotic systems.

• The decision tree is a tool to identify coagulopathies and guide therapy in a standardized way.

Review exercises

TEG parameters

Hemostasis monitoring

Skip exercisesBegin

exercises

Exercise 1: TEG parameters

The R value represents which of the following

phases of hemostasis?a. Platelet adhesion

b. Activation of coagulation pathways and initial fibrin formation

c. Buildup of platelet-fibrin interactions

d. Completion of platelet-fibrin buildup

e. Clot lysis

Answer Next


Select the TEG parameters that demonstrate

kinetic properties of clot formation. (select all that

apply)

a. R

b. Angle ()

c. MA

d. LY30

e. CI

Answer Next


The rate of clot strength buildup is demonstrated

by which of the following TEG parameters?a. R

b. Angle ()

c. MA

d. LY30

e. CI

Answer Next


Which of the following TEG parameters will best

demonstrate the need for coagulation factors

(i.e. FFP)? a. R

b. Angle ()

c. MA

d. LY30

e. CI

Answer Next


Clot strength is dependent on which of the

hemostatic components? a. 100% platelets

b. 80% platelets, 20% fibrinogen

c. 50% platelets, 50% fibrinogen

d. 20% platelets, 80% fibrinogen

e. 100% fibrinogen

Answer Next


Which of the following TEG parameters

demonstrate a structural property of the clot? (select all that apply)

a. R

b. Angle ()

c. MA

d. LY30

e. CI

NextAnswer


Because the TEG is a whole blood hemostasis

monitor, a low MA demonstrating low platelet

function may also influence which of the

following TEG parameters?a. R

b. Angle ()

c. LY30

d. CI

e. None of the above

NextAnswer


Clot stability is determined by which of the following

TEG parameters?

a. R

b. Angle ()

c. MA

d. LY30

e. CI

NextAnswer


Which of the following conditions will provide the

information necessary to determine if heparin is the

cause of bleeding in a patient?

a. R value: Kaolin with heparinase

b. R value: Kaolin vs. Kaolin with heparinase

c. MA value: Kaolin with heparinase

d. MA value: Kaolin vs. kaolin with heparinase

NextAnswer


Which of the following parameters provides an indication

of the global coagulation status of a patient?

a. R

b. Angle ()

c. MA

d. LY30

e. CI

NextAnswer

Exercise 11: Hemostasis monitoring

Which of the following statements are true regarding the

PT and aPTT tests? (select all that apply)

a. Measure coagulation factor interaction in solution

b. Measure platelet contribution to thrombin generation

c. Measure influence of thrombin generation on platelet function

d. Use fibrin formation as an end point

NextAnswer


The TEG analyzer can monitor all phases of hemostasis

except which of the following? (select all that apply)

a. Initial fibrin formation

b. Fibrin-platelet plug construction

c. Platelet adhesion

d. Clot lysis

NextAnswer

Exercise1: TEG parameters

The R value represents which of the following

phases of hemostasis?a. Platelet adhesion

b. Activation of coagulation pathways and initial fibrin formation

c. Buildup of platelet-fibrin interactions

d. Completion of platelet-fibrin buildup

e. Clot lysis

Next

R


Select the TEG parameters that demonstrate

kinetic properties of clot formation. (select all that

apply)

a. R

b. Angle ()

c. MA

d. LY30

e. CI

Next


The rate of clot strength buildup is demonstrated

by which of the following TEG parameters?a. R

b. Angle ()

c. MA

d. LY30

e. CI

Next


Which of the following TEG parameters will best

demonstrate the need for coagulation factors

(i.e. FFP)? a. R

b. Angle ()

c. MA

d. LY30

e. CI

Next


Clot strength is dependent on which of the

hemostatic components? a. 100% platelets

b. 80% platelets, 20% fibrinogen

c. 50% platelets, 50% fibrinogen

d. 20% platelets, 80% fibrinogen

e. 100% fibrinogen

Next


Which of the following TEG parameters

demonstrate a structural property of the clot? (select all that apply)

a. R

b. Angle ()

c. MA (demonstrates maximum clot strength)

d. LY30 (demonstrates clot breakdown or the structural

stability of the clot)

e. CI

Next


Because the TEG is a whole blood hemostasismonitor, a low MA demonstrating low platelet function may also influence which of thefollowing TEG parameters?

a. R – thrombin generation occurs mainly on the surface of platelets, thus a defect in platelet function may slow the rate of thrombin and fibrin formation.

b. Angle () – a defect in platelet function may slow the rate of formation of platelet-fibrin interactions, thus slowing the rate of clot buildup.

c. LY30

d. CI

e. None of the aboveNext


Clot stability is determined by which of the following

TEG parameters?

a. R

b. Angle ()

c. MA

d. LY30

e. CI

Next


Which of the following conditions will provide the

information necessary to determine if heparin is the

cause of bleeding in a patient?

a. R value: Kaolin with heparinase

b. R value: Kaolin vs. Kaolin with heparinase

c. MA value: Kaolin with heparinase

d. MA value: Kaolin vs. kaolin with heparinase

Next


Which of the following parameters provides an indication

of the global coagulation status of a patient?

a. R

b. Angle ()

c. MA

d. LY30

e. CI (Coagulation index: a linear combination of the R, K, angle, and MA)

Next


Which of the following statements are true regarding the

PT and aPTT tests? (select all that apply)

a. Measure coagulation factor interaction in solution

b. Measure platelet contribution to thrombin generation

c. Measure influence of thrombin generation on platelet function

d. Use fibrin formation as an end point

Next


The TEG analyzer can monitor all phases of hemostasis

except which of the following? (select all that apply)

a. Initial fibrin formation

b. Fibrin-platelet plug construction

c. Platelet adhesion (vascular mediated event that occurs in vivo, but not in vitro)

d. Clot lysis

Next

End of Module 2

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Basic Clinician Training Module 2 TEG ® Technology