Aortic Thrombosis in dogs. Williams et al. 2017. JVECC

Question 1

Is aortic thromboembolism or arotic thrombosis more common in dogs?

Answer 1

Aortic thrombosis

Question 2

Was is the most common underlying etiology of aortic thrombosis in dogs?

Answer 2

Kidney disease, i.e., protein-losing nephropathy

Question 3

Which dogs have a better prognosis, dogs with acute versus chronic onset aortic thrombosis?

Answer 3

chronic onset aortic thrombosis

Question 4

Under what shear conditions do “white” clots forms?

Answer 4

high shear condition (>10,000/s)
aortic thrombosis

Question 5

What cells are aortic thrombi mostly made of?

Answer 5

platelets

Question 6

What predominates the platelet adhesion in aortic thrombosis?

Answer 6

von Willebrands factor

Question 7

What shear conditions are “red” clots formed under?

Answer 7

low shear condition (<1,000)
form in venous circulation

Question 8

What cells are venous thrombi mostly made of?

Answer 8

larger amount of red blood cells, WBCs and fibrin
small number of platelets

Question 9

what predominates the platelet adhesion in venous thrombosis?

Answer 9

fibrinogen

Question 10

What is the main mechanism by which PLN leads to hypercoagulable state?

Answer 10

antithrombin loss

others:
* increased platelet reactivity
* increaed activity of FV FVII, FVIII FX
* increased vWF and fibrinogen cc
* reduced plasminogen cc

Question 11

What is the suspected main contributor of arterial thrombosis in dogs with hypothyroidism?

Answer 11

systemic atherosclerosis

Question 12

At what platelet count have dogs with ITP shown to turn from hypocoagulable to hypercoagulable?

Answer 12

TEG tracing showed hypocoagulable state until platelet counts exceeded 40k -> above this hypercoagulable

Question 13

What is the rule of P’s?

Answer 13

Clinical signs of arterial thrombosis or thromboembolism:
* Pain
* Paleness
* Paresthesia
* Pulselessness
* Paresis/Paralysis
* Prostration

Question 14

Of the rule of P’s, what is the most common CS in dogs with arterial thrombosis?

Answer 14

paresis/paralysis

Question 15

Why is recombinant tissue plasminogen activator safer than streptokinase or urokinase?

Answer 15

• rTPA has a high affinity to fibrin-bound plasminogen compared to free plasminogen
• activates the plasminogen on thrombus but not circulating plasminogen -> avoids systemic thrombolytic state -> safer

Question 16

How may aspirin prevent thrombosis?

Answer 16

• inhibits cyclooxygenase -> reduced thromboxane A2 production
• thromboxan A2 = potent platelet agonist

limited evidence of its efficacy

Question 17

How does Clopidogrel prevent thrombosis?

Answer 17

platelet P2Y12 ADP receptor antagonist -> modifies platelet receptor -> prevents platelet activation and aggregation stimulated by ADP

2-4 mg/kg/day

Question 18

How do you monitor efficacy of unfractionated heparin?

Answer 18

aPTT -> target 1.5-2.5 times normal aPTT

Question 19

Why could heparin carry lower efficacy in dogs with PLN?

Answer 19

heparin works via AT enhancement
PLN -> if low AT -> less response to heparin

Question 20

Which LMWH has a higher effect on FXa inhibition, deltaparin or enoxaparin?

Answer 20

Enoxaparin

Question 21

What is the MOA of vitamin K antagonists?

Answer 21

vitamin K epoxide reductase inhibition

Question 22

What is IRN?

Answer 22

internation normalized ratio
used to monitor response to thromboplastin

Question 23

What is the mechanism of Rivaroxaban?

Answer 23

factor Xa inhibition