Thrombotic and Vascular Disease

Question 1

how can you confirm the presence of thrombotic disease?

Answer 1

echocardiography
ultrasound
angiography
CT imaging
MRI

Question 2

what is clopidogrel?

Answer 2

antiplatelet drug

Question 3

what is the mechanism of action of clopidogrel?

Answer 3

irreversibly block ADP binding to P2Y12 receptor on platelet surface

Question 4

what is aspirin?

Answer 4

antiplatelet drug

Question 5

what is unfractionated heparin?

Answer 5

anticoagulant drug

Question 6

what is the mechanism of action of low molecular weight heparins?

Answer 6

inactivates thrombin (mild effect)
inhibits activated factor X (factor Xa)

Question 7

what is the source of a feline aortic thromboembolism?

Answer 7

intracardiac thrombosis: often left atrial appendage

Question 8

what are the 5 P’s of aortic thromboembolism?

Answer 8

pain
paleness/pallor (rear)
pulselessness
poikilothermy (cold)
paresis or paralysis

Question 9

what are some differential diagnoses for feline aortic thromboembolism?

Answer 9

upper motor neuron disease
cardiogenic embolism
pulmonary neoplasia

Question 10

how can you treat an active arterial thromboembolism in a cat?

Answer 10

anticoagulants
analgesics
vasodilators
treat CHF if present
thrombolytics controversial
surgery uncommon

Question 11

what are the two common clinical presentations of canine aortic thrombosis?

Answer 11

acute aortic thromboembolism of cardiogenic origin
slowly growing thrombus in aorta (more common)

Question 12

what drugs can you use to treat canine aortic thrombosis?

Answer 12

coumadin
rivaroxaban
apixaban
heparins acutely
thrombolytics if acute

Question 13

what are the sources of a pulmonary embolism?

Answer 13

dirofilariasis
pulmonary thromboembolism
air embolus
fat embolus
neoplastic embolus
intravascular foreign object

Question 14

what can antithrombin deficiency be due to?

Answer 14

decreased synthesis
increased consumption
loss of antithrombin from intravascular compartment
increased protein catabolism

Question 15

what proteins are major inhibitors of the procoagulant system and are vitamin K dependent?

Answer 15

C
S

Question 16

what are D dimers?

Answer 16

fibrin degradation product seen with thrombolysis

Question 17

what monitoring should be done with clopidogrel?

Answer 17

none

Question 18

what is the mechanism of action of aspirin?

Answer 18

acetylates cyclooxygenase-1 in platelets: inhibition of thromboxane A2 synthesis

Question 19

is there routine monitoring for low molecular weight heparins?

Answer 19

no

Question 20

what is the mechanism of action of thrombolytic drugs?

Answer 20

binds to plasminogen on fibrin surface of thrombus to convert plasminogen to plasmin and then break down thrombus

Question 21

what are some physiologic alterations that predispose to thrombi?

Answer 21

alterations in blood flow
damage to vascular endothelium
hypercoagulability

Question 22

how much of a reduction in antithrombin can predispose to thrombus formation?

Answer 22

modest reduction: 60-70% of normal

Question 23

what tests can be done to increase suspicion of thrombotic disease?

Answer 23

platelet count
PT and PTT
D-dimers
TEG
antithrombin levels

Question 24

what are some thrombolytic drugs?

Answer 24

tissue plasminogen activator
streptokinase
urokinase

Question 25

what are some side effects of clopidogrel?

Answer 25

bleeding
foaming at mouth
icterus and increased bilirubin
hepatic metabolism: variable effect

Question 26

what are some side effects of aspirin?

Answer 26

GI ulceration or vomiting or anorexia
GI bleeding
kidney concerns if volume depleted

Question 27

what do you adjust the dose of unfractionated heparin based on?

Answer 27

changes in PTT

Question 28

what is the mechanism of action of warfarin?

Answer 28

inhibits vitamin K-dependent clotting factors

Question 29

what are the potential side effects of warfarin?

Answer 29

lethal bleeding and anemia

Question 30

what leads to thee thrombus forming in feline aortic thromboembolism?

Answer 30

blood stasis/abnormal flow
hyperreactivity of feline platelets
LA stretch: collagen exposure and tissue factor activation

Question 31

are antiplatelet drugs and low molecular weight heparins usually enough to resolve a canine aortic embolism?

Answer 31

no