Thrombotic and Vascular Disease Flashcards
how can you confirm the presence of thrombotic disease?
echocardiography
ultrasound
angiography
CT imaging
MRI
what is clopidogrel?
antiplatelet drug
what is the mechanism of action of clopidogrel?
irreversibly block ADP binding to P2Y12 receptor on platelet surface
what is aspirin?
antiplatelet drug
what is unfractionated heparin?
anticoagulant drug
what is the mechanism of action of low molecular weight heparins?
inactivates thrombin (mild effect)
inhibits activated factor X (factor Xa)
what is the source of a feline aortic thromboembolism?
intracardiac thrombosis: often left atrial appendage
what are the 5 P’s of aortic thromboembolism?
pain
paleness/pallor (rear)
pulselessness
poikilothermy (cold)
paresis or paralysis
what are some differential diagnoses for feline aortic thromboembolism?
upper motor neuron disease
cardiogenic embolism
pulmonary neoplasia
how can you treat an active arterial thromboembolism in a cat?
anticoagulants
analgesics
vasodilators
treat CHF if present
thrombolytics controversial
surgery uncommon
what are the two common clinical presentations of canine aortic thrombosis?
acute aortic thromboembolism of cardiogenic origin
slowly growing thrombus in aorta (more common)
what drugs can you use to treat canine aortic thrombosis?
coumadin
rivaroxaban
apixaban
heparins acutely
thrombolytics if acute
what are the sources of a pulmonary embolism?
dirofilariasis
pulmonary thromboembolism
air embolus
fat embolus
neoplastic embolus
intravascular foreign object
what can antithrombin deficiency be due to?
decreased synthesis
increased consumption
loss of antithrombin from intravascular compartment
increased protein catabolism
what proteins are major inhibitors of the procoagulant system and are vitamin K dependent?
C
S
what are D dimers?
fibrin degradation product seen with thrombolysis
what monitoring should be done with clopidogrel?
none
what is the mechanism of action of aspirin?
acetylates cyclooxygenase-1 in platelets: inhibition of thromboxane A2 synthesis
is there routine monitoring for low molecular weight heparins?
no
what is the mechanism of action of thrombolytic drugs?
binds to plasminogen on fibrin surface of thrombus to convert plasminogen to plasmin and then break down thrombus
what are some physiologic alterations that predispose to thrombi?
alterations in blood flow
damage to vascular endothelium
hypercoagulability
how much of a reduction in antithrombin can predispose to thrombus formation?
modest reduction: 60-70% of normal
what tests can be done to increase suspicion of thrombotic disease?
platelet count
PT and PTT
D-dimers
TEG
antithrombin levels
what are some thrombolytic drugs?
tissue plasminogen activator
streptokinase
urokinase
what are some side effects of clopidogrel?
bleeding
foaming at mouth
icterus and increased bilirubin
hepatic metabolism: variable effect
what are some side effects of aspirin?
GI ulceration or vomiting or anorexia
GI bleeding
kidney concerns if volume depleted
what do you adjust the dose of unfractionated heparin based on?
changes in PTT
what is the mechanism of action of warfarin?
inhibits vitamin K-dependent clotting factors
what are the potential side effects of warfarin?
lethal bleeding and anemia
what leads to thee thrombus forming in feline aortic thromboembolism?
blood stasis/abnormal flow
hyperreactivity of feline platelets
LA stretch: collagen exposure and tissue factor activation
are antiplatelet drugs and low molecular weight heparins usually enough to resolve a canine aortic embolism?
no
