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Coag Made EasyCoag Made Easy

Alice Ma, M.D.Alice Ma, M.D.

University of North Carolina-Chapel HillUniversity of North Carolina-Chapel Hill

Division of HematologyDivision of Hematology

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Disclosures

• Nothing to disclose

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Coagulation made easyCoagulation made easy

The PTT Pathway The PT Pathway

Rather than thinking about the intrinsic and theextrinsic pathways,

 think about the PTT and the PTpathwways

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Coagulation made easyCoagulation made easy

X

The PTT Pathway The PT Pathway

The PT and the PTTpathway meet at factor X,because “X” marks thespot

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Coagulation made easyCoagulation made easy

V

X

The PTT Pathway The PT Pathway

Factor V is a cofactor forfactor X, and you canremember this because Vfits into the notch of the X

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Coagulation made easyCoagulation made easy

V

X

Prothrombin Thrombin

The PTT Pathway The PT Pathway

Factor Xa conerts prothrombin !Factor ""# intothrombin, the most important en$yme on the p%anet

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Coagulation made easyCoagulation made easy

V

X

Prothrombin Thrombin

Fibrinogen Fibrin

The PTT Pathway The PT Pathway

Thrombin, among other

things, conerts the so%umo%ecu%e fibrinogen intoso%id fibrin c%ot

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The Common Pathway = Small Bills

V + X

II = prothrombin

I = fibrinogen

&ou can remember the factors in the common pathway by remembering thebi%%s in your wa%%et sma%%er than a '()* +ont forget the '( bi%% --

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Coagulation made easy - the PTCoagulation made easy - the PT

Prothrombin Thrombin

Fibrinogen Fibrin

.

V

X

The PT PathwayPT has one %ess %etter than PTT,and PT a%ues are shorter thanPTT a%ues, because thepathway is shorter* "t meansthat the PT pathway is a%soshorter* This means that theresfewer steps to remember, andthis is %ucky, so the %ucky PTpathway uses %ucky factor . toactiate factor X

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Coagulation made easy - the aPTTCoagulation made easy - the aPTT

Prothrombin Thrombin

Fibrinogen Fibrin

V

X

X""X"

"X

V"""

The PTT pathway has a%% thosehideous roman numera%s* * */ow are we going to rememberthem0 /mmmmm* * * * * * *

The PTT Pathway

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Coagulation made easy - the aPTTCoagulation made easy - the aPTT

Prothrombin Thrombin

Fibrinogen Fibrin

T

NE

T  V

X

E

The PTT Pathway

1e%%, 2ust remember that thePTT is a basic T343T ofhemato%ogy*T343T stands for* * * * * *

C l i d h PTT

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Coagulation made easy - the aPTTCoagulation made easy - the aPTT

Prothrombin Thrombin

Fibrinogen Fibrin

Twelve

Nine

EightTenV

X

Eleven

The PTT Pathway

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Coag Made Easy: PT and PTT both Prolonge

V

X

Prothrombin (II)

Fibrinogen

The PTT Pathway The PT Pathway

These factors are in the

common pathway

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Coag Made Easy: Only PT Prolonged

.

+eficiency of Factor V"" wi%% pro%ong the PT but not the PTT

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Coag Made Easy: Only PTT Prolonged

Twelve

Nine

Eight

Ten

Eleven

+eficiencies of Factors 5(, 55, 6and 7 wi%% pro%ong the PTT and

not the PT* Remember thatfactor 5) is in the common

pathway, and affects 89T/ the

PT and the PTT

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• Deficiencies of factor XI,Deficiencies of factor XI,IX, VIII, VII. X, V,IX, VIII, VII. X, V,

prothrombin andprothrombin and

fibrinogen are clinicallyfibrinogen are clinically

significant.significant.

• Inhibitors of these factorsInhibitors of these factors

are clinically significantare clinically significant

for bleeding.for bleeding.

• Deficiency of Factor XII,Deficiency of Factor XII,and the presence of theand the presence of the

lupus anticoagulant arelupus anticoagulant are

not.not.

XII

XIIX

X

VIII VII

Thrombin

V

Fibrinogen Fibrin

What matters clinically

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Coagulation Made Easy- The Mixing StudyCoagulation Made Easy- The Mixing Study

• Useful to differentiate etiologies of prolonged clotting in aUseful to differentiate etiologies of prolonged clotting in acoagulation assay.coagulation assay.

• PatientPatient’s plasma is mixed 50:50 with normal plasma.’s plasma is mixed 50:50 with normal plasma.

Coagulation assay is repeated.Coagulation assay is repeated.

• IfIf “substantial” correction is noted after mix, suspect“substantial” correction is noted after mix, suspect clottingclotting

factor deficiencyfactor deficiency. ‘cause you replaced deficient factors in the. ‘cause you replaced deficient factors in the

patient plasma with normal factors from the normal plasmapatient plasma with normal factors from the normal plasma

• If no or not full correction seen, suspectIf no or not full correction seen, suspect inhibitorinhibitor. ‘cause you. ‘cause you

added the inhibitor (think of this as an anticoagulant) in theadded the inhibitor (think of this as an anticoagulant) in the

patient plasma which inhibits clotting in the normal plasmapatient plasma which inhibits clotting in the normal plasma