Secondary Hemostasis (Coagulation Cascade)

Name the INTRINSIC, EXTRINSIC, and COMMON coagulation factors in order of how they appear.

Intrinsic: XII, XI, IX, VIII

Extrinsic: VII

Common: X, V, II

If we are thinking about the coagulation cascade diagram, the left side represents the —- pathway and is composed of —- factor(s). The right side represents the —- pathway and is composed of —- factor(s). They meet and continue down the —- pathway, which has —- factor (s). At the end of this pathway, factor(s) —— mediate fibrinogen's transfer to fibrin.

Intrinsic

4

Extrinsic

1

Common

3

I (One)

What is the ONLY extrinsic clotting factor?

Factor VII

What is the ultimate goal of the coagulation cascade?

Turn fibrinogen to fibrin to hold platelet plug in place

True or False: All of the coagulation factors are enzymes that are not consumed.

False! Factor V, VIII, and I/Ia (Fibrinogen) are consumed, but the others are NOT consumed.

Name the vitamin K-dependent coagulation factors.

Factors II, VII, IX, and X

Vitamin K-dependent coagulation factors are important in —- poisoning.

Rodenticide (Warfarin)

True or False: The half-life of the coagulation factors is variable, depending on the specific factor.

True!

What THREE evaluations on bloodwork directly provide information about platelets?

PLT (platelet count)

MPV (mean platelet volume)

BMBT (buccal mucosal bleeding time)

What lab evaluation(s) provides information on the extrinsic AND common pathways?

PT (prothrombin time)

What lab evaluation(s) provide information on the intrinsic AND common pathways?

PTT (partial thromboplastin time)

ACT (activated clotting time)

Which coagulation lab evaluation is not used often, as it requires a special tube AND platelets?

What kind of tube is required?

ACT

Grey top (diatomaceous earth)

What lab evaluation(s) provide information on SOLELY the common pathway?

Thrombin time (TT)

All coagulation evaluations should be sample and placed in a —- tube, except for —-, which is placed in a —- tube.

Blue (citrate)

ACT

Grey (diatomaceous earth)

Match the level of factor activity to the coagulation lab evaluation type:

<30%

<5%

<30%

ACT

PTT

PT

PT: <30%

PTT:<30%

ACT:<5%

What is the first coagulation lab evaluation that is the first to be prolonged with vitamin K deficiency/rodenticide?

PT (prothrombin time)

Why can a purple top not be used for coagulation tests?

EDTA binds Ca2+ irreversibly and removes it from the sample, while citrate reversibly binds Ca2+ and can be added back to the sample to make the blood clot.

What is the precise ratio of blood:citrate in a blue top tube that is crucial for the clotting to occur appropriately?

9:1

True or False: ACT is the only coagulation test that requires platelets.

True!

When is TT (thrombin time) prolonged?

Decreased fibrinogen (not enough "ingredients" based on blood:citrate ratio)

What are the TWO specialized coagulation tests that can be performed?

Thromboelastography/thromboelastometry- efficiency of clot formation

Sonoclot- idk man i can't see it.. something about strength lol

If you have a patient with normal PLT and PT but prolonged PTT and ACT, what pathway is most likely affected?

Intrinsic pathway

If you have a patient with normal PLT, PTT, and ACT but a prolonged PT, what pathway is most likely affected?

Extrinsic pathway

What process keeps everything from clotting?

Fibrinolysis

Placeholder for slide 23 plasminogen,etc about how fibrinolysis works

K

What THREE values can be obtained during a laboratory evalutation of fibrinolysis?

Fibrin degradation products (FDPs)

D-dimers

Protein C

True or False: All of the fibrinolysis evaluation tests should be sampled using a blue top.

True!

What do FDPs measure?

How are the results reported?

Breakdown products of fibrin

Dilutions

True or False: FDPs are nonspecific- they can be increased with bleeding or inflammation.

True!

True or False: Fibrin must have been previously cross-linked in order for an FDP to be interpreted correctly.

False! Fibrin does NOT have to be previously cross-linked (doesn't tell that fibrin pieces came out of a clot since nonspecific)

What do D-dimers measure?

When might you see increased levels of this?

Breakdown products of CROSS-LINKED fibrin (previously in blood clot; specific)

Abnormal thrombosis

What laboratory test is a "physiological anticoagulant," meaning it constantly circulates in the body?

Protein C

What does Protein C cause proteolysis of?

What pathways are impacted then?

Factors Va and VIIIa

Common (V) and intrinsic (VIII)

When might you get decreased levels of Protein C?

Hypercoagulable states (blood clots inappropriately)

What does a lowercase "a" indicate on the end of a coagulation factor?

It has been activated

True or False: Protein C prevents excessive clotting.

True!

What are the THREE major types of anticoagulants? Give examples of each.

Calcium binders (citrate; EDTA)

Enzyme inhibitors (heparin)

Vitamin K inhibitors (coumarin)

What does PIVKA stand for?

Proteins Induced by Vitamin K Absence or Antagonism

When do vitamin K epoxide levels increase?

Inhibition of vitamin K reductase

True or False: PIVKA are inactive proteins that are similar to Factors II, VII, IX, and X.

True!

What will you see an increase in PIVKA levels prior to?

Prolonged PT and PTT

What is the most common inherited coagulation defect in the extrinsic pathway?

What is it commonly associated with?

Factor VII deficiency

Demodex

True or False: There are minimal bleeding problems with extrinsic pathway defects since there is only one factor associated with that pathway.

True!

There are inherited coagulation defects in all of the intrinsic pathways, but there are TWO that are the most common. Name them and provide their unique names.

Factor VIII (Hemophilia A)

Factor IX (hemophilia B)

Are there usually issues in the common pathway with inherited coagulation defects?

No, they are rare

Name the THREE major acquired coagulation defects.

Vitamin K deficiency

Severe liver disease

Disseminated intravascular coagulation (DIC)

What factors will be decreased with Vitamin K deficiency?

What is this most commonly seen with?

II, VII, IX, X

Warfarin poisoning (rodenticide)

Acquired coagulation defects can be due to severe liver disease because all factors except —- are formed in the liver. Bleeding is —- and usually —- in the disease progression.

VIII

Minimal

Late

DIC has many mechanisms. What overall happens in DIC?

What does it activate?

What is the ultimate result in untreated DIC?

Widespread activation of clotting

Clotting and fibrinolytic cascades

Microthrombi -> organ failure

In inherited coagulation defects, there is/are usually —- defective factor(s), but there is/are —- in acquired defects.

One

Multiple

You have a patient with a normal PLT, TT, and FDPs. ACT, PTT, and PT are prolonged. Where is the problem?

Is this most likely an inherited or acquired defect?

In all three pathways

Acquired