A Surgical Perspective of Coagulation

Question 1

The aPTT test is used to measure the effectiveness of the ___ and ___ pathway. It is used to monitor the patient’s response to ____ therapy.

Answer 1

intrinsic; common; heparin

Question 2

Some examples of acquired bleeding disorders are caused by:

Answer 2

cirrhosis, medications, liver diseases, blood thinning drugs, patients on chemotherapy, kidney failure, acquired platelet function defect

Question 3

Management of patients receiving anti-platelet and anticoagulant therapy requires _____ education as new medications become available.

Answer 3

continual

Question 4

Are acquired or congenital bleeding disorders more common and seen in everyday practice?

Answer 4

acquired

Question 5

A local ____ measure can stabilize a blood clot (e.g. gel foam, absorbable hemostat)

Answer 5

hemostatic

Question 6

What organ makes most of the clotting factors?

Answer 6

liver

Question 7

How to manage patients with bleeding disorders:

Answer 7

medical consultation
assessment of lab results
referral to OMFS
determine withdrawal of anticoagulant/anti-platelet meds
bridging therapy
local measures to control bleeding (GelFoam etc.)

Question 8

What is an normal aPTT value?

Answer 8

30-40 seconds

Question 9

Normal hemostasis is dependent upon ___.

Answer 9

vessel wall integrity
adequate number of platelets
platelets that function properly
adequate levels of clotting factors
proper function of fibrinolytic pathway

Question 10

The INR target range is 2.5 (2.0-3.0) in which circumstances?

Answer 10

atrial fibrillation
ischemic stroke, transient ischemic attack, embolism
mitral stenosis
planned cardioversion
after open heart surgery

Question 11

What are some common causes of a prolonged aPTT?

Answer 11

hemophilia, von Willebrand disease, liver cirrhosis, vitamin K deficiency, heparin therapy, warfarin therapy

Question 12

What bleeding time would signify platelet dysfunction?

Answer 12

9-15 minutes

Question 13

This injectable medication causes a three to four fold increase in the factor VIII coagulant activity.

Answer 13

desmopressin

Question 14

What are common causes of prolonged prothrombin time?

Answer 14

Warfarin use, vitamin K deficiency, liver disease (diminished synthesis of clotting factors)

Question 15

Patients on oral anticoagulant treatment are currently _____ to discontinue their medication prior to minor dental surgery because this increases their risk of developing a ______ episode.

Answer 15

NOT recommended; thromboembolic

Question 16

The decision for the patient to come off of blood thinners ___ be made by the practicing dentist.

Answer 16

CANNOT

Question 17

___ clot formation is impaired in patients with decreased levels of factors VIII and IX.

Answer 17

Fibrin

Question 18

The prothrombin time (PT) tests the rate of conversion of ___ to ___ in the extrinsic pathway.

Answer 18

VII; VIIa

Question 19

What is a normal bleeding time for a precise nick?

Answer 19

2-9 minutes

Question 20

Which injectable medications inhibit fibrinolysis and allow teeth to be extracted under their cover?

Answer 20

aminocaproic acid and tranexamic acid

Question 21

What are pre- and postoperative therapy options for patients who have hemophilia?

Answer 21

giving cryoprecipitate before treatment; avoidance of block local anesthetic; use of splints to retain tenous blood clots in sockets, etc.

Question 22

Desmopressin ____ the production of von Willebrand factor.

Answer 22

increases

Question 23

What happens during the vascular phase of hemostasis?

Answer 23

constriction of the injured blood vessel to diminish blood flow

Question 24

What is a normal PT value?

Answer 24

12-13 seconds

Question 25

An elevated aPTT is seen when factor VIII or IX levels fall below ___ to ___.

Answer 25

30% to 50%

Question 26

A defective von Willebrand factor interaction between platelets and the vessel wall impairs ____ hemostasis.

Answer 26

primary

Question 27

An elevated bleeding time, normal platelet count, and no history of aspirin/NSAID use should prompt the dentist to consider ____.

Answer 27

von Willebrand disease

Question 28

Thrombocytopenia is a ____ platelet count and ____ bleeding time.

Answer 28

decreased; elevated

Question 29

What can a platelet count or complete blood count tell clinicians?

Answer 29

if patients are likely to clot or suffer from thrombocytopenia or spontaneous bleeding

Question 30

Patients who discontinue warfarin for a few days prior to surgery and are treated with heparin are said to be on a _____ treatment.

Answer 30

bridging

Question 31

A critical blood clotting gene is carried on the __ chromosome.

Answer 31

X

Question 32

What happens during the coagulation phase of hemostasis?

Answer 32

fibrinogen gets converted to fibrin; fibrin tightly binds the platelets to form a clot; gives rise to a more stable clot

Question 33

_____ activates fibrin, but also activates plasmin during fibrinolysis (clot dissolution).

Answer 33

Thrombin

Question 34

What happens during the platelet phase of hemostasis?

Answer 34

formation of a loose and temporary platelet plug; platelets bind to collagen; platelets aggregate to form the hemostatic primary plug in the presence of fibrinogen

Question 35

The liver produces all coagulation factors except ____.

Answer 35

factor VIII (also potentially factor XIII)