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Questions and Answers
What is a characteristic of direct Xa inhibitors like Rivaroxaban and Apixaban?
What is a characteristic of direct Xa inhibitors like Rivaroxaban and Apixaban?
Which anticoagulant has been recommended for cats to prevent ATE?
Which anticoagulant has been recommended for cats to prevent ATE?
What is a potential drawback of using direct Factor Xa inhibitors?
What is a potential drawback of using direct Factor Xa inhibitors?
In the context of ATE recurrence in cats, what was the median time with clopidogrel in the FATCAT study?
In the context of ATE recurrence in cats, what was the median time with clopidogrel in the FATCAT study?
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Which combination therapy case report showed a specific median time to ATE recurrence?
Which combination therapy case report showed a specific median time to ATE recurrence?
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What condition is NOT associated with an increased risk of thrombosis in animals?
What condition is NOT associated with an increased risk of thrombosis in animals?
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What factor worsens the prognosis in cases of sepsis?
What factor worsens the prognosis in cases of sepsis?
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Which condition is a known risk factor for jugular thrombophlebitis in horses?
Which condition is a known risk factor for jugular thrombophlebitis in horses?
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Which scenario is a primary indication for anticoagulant drugs?
Which scenario is a primary indication for anticoagulant drugs?
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Which of the following is NOT typically a risk factor for thrombosis related to catheter use?
Which of the following is NOT typically a risk factor for thrombosis related to catheter use?
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In which animal condition is anticoagulation always indicated?
In which animal condition is anticoagulation always indicated?
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Which gastrointestinal disease is associated with an increased risk of thrombosis in horses?
Which gastrointestinal disease is associated with an increased risk of thrombosis in horses?
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What is a common cause of cerebrovascular disease?
What is a common cause of cerebrovascular disease?
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Which of the following is NOT a characteristic sign of thrombosis during a physical exam?
Which of the following is NOT a characteristic sign of thrombosis during a physical exam?
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What is a major consequence of thrombosis that may lead to sudden death?
What is a major consequence of thrombosis that may lead to sudden death?
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Which diagnosis method is used to identify thrombi in situ?
Which diagnosis method is used to identify thrombi in situ?
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What causes pulmonary thromboembolism?
What causes pulmonary thromboembolism?
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Which of the following factors is NOT part of Virchow's theory of hypercoagulability?
Which of the following factors is NOT part of Virchow's theory of hypercoagulability?
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Which condition is indicated by thrombophlebitis?
Which condition is indicated by thrombophlebitis?
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What is a consequence of endothelial dysfunction related to thrombosis?
What is a consequence of endothelial dysfunction related to thrombosis?
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Which organ dysfunction is primarily linked with microthrombosis?
Which organ dysfunction is primarily linked with microthrombosis?
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What condition can lead to an increased risk of thrombosis due to elevated procoagulant proteins?
What condition can lead to an increased risk of thrombosis due to elevated procoagulant proteins?
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Which of the following is a characteristic of arterial clots?
Which of the following is a characteristic of arterial clots?
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What contributes to the hypercoagulable state by decreasing anticoagulant proteins?
What contributes to the hypercoagulable state by decreasing anticoagulant proteins?
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What is the effect of blood stasis on the coagulation pathway?
What is the effect of blood stasis on the coagulation pathway?
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Which type of clots are typically formed in low-pressure environments and are rich in fibrin?
Which type of clots are typically formed in low-pressure environments and are rich in fibrin?
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In feline cardiac disease, which factor is a significant risk for thrombosis?
In feline cardiac disease, which factor is a significant risk for thrombosis?
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Which of the following factors is likely to activate intrinsic pathway thrombosis?
Which of the following factors is likely to activate intrinsic pathway thrombosis?
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Antiplatelet agents are primarily used for which type of clots?
Antiplatelet agents are primarily used for which type of clots?
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Which condition has a strong risk of thrombosis that warrants anticoagulant consideration?
Which condition has a strong risk of thrombosis that warrants anticoagulant consideration?
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Which condition has an insufficient risk of thrombosis according to the data provided?
Which condition has an insufficient risk of thrombosis according to the data provided?
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For which condition is it recommended to use antithrombotic agents despite having a weak risk factor for thrombosis?
For which condition is it recommended to use antithrombotic agents despite having a weak risk factor for thrombosis?
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What is a common feature of both pancreatitis and hyperadrenocorticism in relation to thrombosis risk?
What is a common feature of both pancreatitis and hyperadrenocorticism in relation to thrombosis risk?
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Which condition poses a moderate to strong risk of thrombosis according to available evidence?
Which condition poses a moderate to strong risk of thrombosis according to available evidence?
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What is stated about the superiority of anticoagulant drugs in veterinary medicine?
What is stated about the superiority of anticoagulant drugs in veterinary medicine?
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Which condition is associated with an individual variable risk of thrombosis?
Which condition is associated with an individual variable risk of thrombosis?
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Which of the following correctly identifies a condition where antithrombotics are not recommended?
Which of the following correctly identifies a condition where antithrombotics are not recommended?
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What is a potential complication of using unfractionated heparin (UFH) in horses?
What is a potential complication of using unfractionated heparin (UFH) in horses?
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Which of the following is NOT a characteristic of Low Molecular Weight Heparin (LMWH)?
Which of the following is NOT a characteristic of Low Molecular Weight Heparin (LMWH)?
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How does heparin affect hyperlipidemia?
How does heparin affect hyperlipidemia?
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Which of the following is a potential use of LMWH in horses?
Which of the following is a potential use of LMWH in horses?
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What is a significant advantage of LMWH over UFH in treating thrombosis?
What is a significant advantage of LMWH over UFH in treating thrombosis?
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What is the primary mechanism by which heparin exerts its antithrombotic effect?
What is the primary mechanism by which heparin exerts its antithrombotic effect?
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What does the phrase "individual variation in optimal UFH dose likely" mean?
What does the phrase "individual variation in optimal UFH dose likely" mean?
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How can the effectiveness of LMWH be measured?
How can the effectiveness of LMWH be measured?
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Flashcards
Thrombosis Risk in IMHA
Thrombosis Risk in IMHA
IMHA (Immune-Mediated Hemolytic Anemia) has a strong risk of thrombosis.
Thrombosis Risk in PLN (Dogs)
Thrombosis Risk in PLN (Dogs)
Dogs with PLN (Protein-Losing Nephropathy) have a yes risk for thrombus formation.
Thrombosis Risk in Pancreatitis
Thrombosis Risk in Pancreatitis
Pancreatitis presents a yes risk for thrombosis in affected animals.
Thrombosis in Neoplasia
Thrombosis in Neoplasia
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Thrombosis Risk in Feline Heart Disease
Thrombosis Risk in Feline Heart Disease
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Antithrombotics Recommendation for Heartworm
Antithrombotics Recommendation for Heartworm
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Anticipating Thrombosis in IMHA (Cats)
Anticipating Thrombosis in IMHA (Cats)
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Antithrombotic Classes
Antithrombotic Classes
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Direct Xa inhibitors
Direct Xa inhibitors
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Predictable pharmacokinetics
Predictable pharmacokinetics
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Irreversible inhibition
Irreversible inhibition
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Clopidogrel in cats
Clopidogrel in cats
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Combination therapy in cats
Combination therapy in cats
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Hypercoagulable state
Hypercoagulable state
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Procoagulant proteins
Procoagulant proteins
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Anticoagulant proteins
Anticoagulant proteins
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Blood stasis
Blood stasis
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Intrinsic pathway
Intrinsic pathway
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Arterial clots
Arterial clots
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Venous clots
Venous clots
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Feline cardiac disease
Feline cardiac disease
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Septic peritonitis risk
Septic peritonitis risk
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Neonatal sepsis
Neonatal sepsis
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Jugular thrombophlebitis
Jugular thrombophlebitis
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Cancer and thrombosis
Cancer and thrombosis
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Indications for anticoagulants
Indications for anticoagulants
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Cerebrovascular disease
Cerebrovascular disease
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Extracorporeal circuits risk
Extracorporeal circuits risk
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Antithrombotics guideline
Antithrombotics guideline
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Heparin
Heparin
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Unfractionated Heparin (UFH)
Unfractionated Heparin (UFH)
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Low-Molecular Weight Heparin (LMWH)
Low-Molecular Weight Heparin (LMWH)
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Dalteparin
Dalteparin
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Enoxaparin
Enoxaparin
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Anti-Xa activity
Anti-Xa activity
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Erythrocyte agglutination
Erythrocyte agglutination
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Hyperlipemia treatment
Hyperlipemia treatment
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Thrombosis
Thrombosis
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Thromboembolism
Thromboembolism
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Obstructive shock
Obstructive shock
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Microthrombosis
Microthrombosis
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Ischemic myopathy
Ischemic myopathy
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Thrombophlebitis
Thrombophlebitis
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Pulmonary thromboembolism
Pulmonary thromboembolism
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Hypercoagulability
Hypercoagulability
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Study Notes
Thrombosis in Veterinary Medicine
- Thrombosis and thromboembolism
- Obstructive shock
- Impaired regional oxygen delivery
- Impaired blood flow
- Organ dysfunction/failure
- Primarily microthrombosis
- Complications of therapy, e.g., catheter associated thrombosis
Diagnosis of Thrombosis
- Physical exam
- Affected extremity is often colder than others
- Ischemic muscles are painful and hard (ischemic myopathy)
- Thrombophlebitis (warmth and swelling over a vein, usually at site of prior venipuncture or catheter)
- Signs of organ failure
- Pulmonary thromboembolism (characterized by acute dyspnea)
- Acute kidney injury
- Hepatic injury
- Stroke or other acute neurologic decline
- Sudden death may occur from massive thrombosis
- Ultrasound or other imaging (e.g. CT) may identify thrombi in situ
Hypercoagulability: Theory
- Virchow (circa 1845)
- Endothelial damage
- Hypercoagulable state
- Blood stasis/ alterations in blood flow
Endothelial Dysfunction
- Alterations of glycocalyx exposing procoagulant triggers
- Inflammation
- Fluid therapy
- Direct injury
- Release of von Willebrand factor (vWF)
- Activated endothelial cell
Hypercoagulable State
- Increased procoagulant proteins
- Sepsis
- Inflammation
- Surgery, including surgery for fibrinogen
- Hyperadrenocorticism (heredity may be a factor)
- Increased heritability
- Decreased anticoagulant proteins
- Sepsis
- Inflammation
- Gastrointestinal (GI) disease
- Renal disease
Blood Stasis
- Activation of intrinsic pathway
- Decreased blood flow
- Abnormal blood flow
- Intravascular foreign material
- Negative charge
- Biofilm production
Arterial vs Venous Thrombosis
- Arterial clots ("white clots")
- Predominantly platelets
- Activated with high shear blood flow
- Antiplatelet agents are the primary therapy
- Venous clots ("red clots")
- Low pressure/venous stasis
- Rich in fibrin, erythrocytes
- Anticoagulant agents are the primary therapy
Cardiac Disease
- Feline cardiac disease
- Left atrial dilation
- Spontaneous echocontrast
- Reduced left atrial appendage flow velocity
- Thromboembolic sequelae (primarily arterial thromboembolism (ATE)).
- Heartworm (pulmonary artery thrombosis)
- Worm thrombus vs. clot
- Transvenous pacemakers
- Uncommon clot formation on leads
Immune-mediated Hemolytic Anemia (IMHA)
- Strongly associated with thrombosis in dogs
- Anticoagulation is standard therapy component
- Risk factors include:
- Severe inflammatory response
- High fibrinogen, decreased antithrombin
- RBC membranes in the circulation
- Corticosteroid therapy
- IV access, sometimes multiple
- Multiple blood transfusions
Protein Losing Conditions
- Protein losing nephropathy (PLN)
- Associated with thrombosis
- Possibly due to loss of antithrombin
- Protein losing enteropathy (PLE)
- Loss of proteins including antithrombin
- Small and large animals
Glucocorticoids, Hyperadrenocorticism
- Treatment with corticosteroids is associated with a hypercoagulable state
- Risk of thrombosis with hyperadrenocorticism (dogs)
Infectious Disease
- Dogs with sepsis (especially endocarditis, septic peritonitis, aspiration pneumonia) without coagulopathy are at risk of thrombosis
- Does not support routine anticoagulation in septic dogs
- Neonatal sepsis (foals)
- Presence of coagulopathy worsens prognosis
- EHV-1 infection (adult horses)
- Vasculitis, thrombosis → myeloencephalopathy
Equine Gastrointestinal Disease
- Jugular thrombophlebitis or other thrombosis
- Ischemic/strangulating Gl lesions
- Colitis
- Duodenitis/proximal jejunitis
- Right dorsal colitis
- Jugular thrombophlebitis is more likely in horses with surgically treated colic that develop fever or diarrhea.
- Salmonellosis (also a risk factor)
- Thrombosis may initiate at venipuncture site or on catheter
Other Conditions
- Neoplasia
- Carcinomas in dogs are associated with a risk of thrombosis.
- Overall prevalence is unknown.
- Cerebrovascular disease
- May result from a thrombotic event (rather than cause).
- Pancreatitis (dogs)
- Extracorporeal circuits (e.g., dialysis)
- Activates coagulation during treatment
Vascular Access/Devices
- Transvenous pacemaker leads
- IV catheters
- Central lines
- Catheter-associated thrombi are common in patients with severe inflammation.
- Consideration of the number and type of venous catheter is important
- Catheter alone is not usually a risk factor.
When are Anticoagulant Drugs Indicated?
- Animals with existing thrombi/thromboembolism
- Animals with a single strong risk factor
- Animals with multiple moderate risk factors
- Always indicated for dogs with IMHA, cats with heart disease
Disease Risk Factor Summary
- Table summarizes conditions, thrombosis risk levels, and recommended anticoagulation use.
Anticoagulant Drugs
- Absence of clear evidence for any single drug/class superiority
- Specific mechanisms (e.g., platelet vs factor)
- Ease of administration; cost
Acetylsalicylic Acid (ASA; Aspirin)
- Inhibits cyclooxygenase (COX)
- Prevents production of AA metabolite thromboxane (TXA2)
- Thromboxane is a potent platelet agonist, vasoconstrictor
- Irreversible COX inhibition
- Decreases platelet aggregation in dogs
- Does reliably impact platelet aggregation in cats or horses
FAT-CAT: Aspirin vs Clopidogrel
- Prevention of recurrent ATE in cats
- 42 dogs, 18.75 mg po q24
- 43 ASA, 81mg po q72h
- Recurrent TE in:
- 19/39 clopidogrel (49%)
- 27/36 ASA (75%)
- Median time to recurrence
- 443 days, (7-990 days) clopidogrel
- 192 days, (6-883 days) ASA
Heparin
- Potentiates AT inhibition (unfractionated heparin (UFH))
- Binds antithrombin (AT) and Flla, FXa
- Low-Molecular weight heparin (LMWH)
- Binds Xa
- Dalteparin
- Enoxaparin
- Binds Xa
- Can measure anti-Xa activity to dose either directly
- Directly correlated to drug
Types of Heparins
- Unfractionated Heparin (UFH)
- In dogs/cats/horses with risk of thrombosis
- Variability in optimal UFH dose
- Interactions with plasma proteins, endothelial cells, macrophages
- Bleeding - less specific binding to clotting factors (esp. lla)
- Erythrocyte agglutination and thrombocytopenia (horses)
- Low molecular weight heparin (LMWH)
- Used in dogs, cats, and horses with variable dosing regimens
- More frequent dosing is often needed to achieve similar efficacy compared to humans
- More predictable PK/PD
- Not associated with RBC agglutination in horses
Other Uses for Heparin in Horses
- Hyperlipemia
- Increased release of lipoprotein lipase
- Increased release of hepatic lipase
- LMWH may prevent platelet activation from EHV-1
- Adhesion prevention: effective
Direct Xa Inhibitors
- Rivaroxaban (Xarelto); apixaban (Elliquis)
- Inhibit Factor Xa directly
- No need for antithrombin
- Predictable pharmacokinetics
- Irreversible inhibition of Factor Xa
- Well-tolerated in dogs and cats
Antiplatelet Agents vs Anticoagulants for ATE
- Dogs
- Antiplatelet agents may be more effective
- Anticoagulants also effective
- Cats
- Clopidogrel recommended for ATE prevention.
Combination Therapy
- Combination associated with high incidence of bleeding complications
- Especially GI (PPI is recommended)
- Clopidogrel preferred over ASA
- Deescalate therapy (often antiplatelet drug) after acute need, based on risk
- Coadministration of rivaroxaban/clopidogrel (rare)
- Bleeding in one dog (0.8mg/kg RVX, 4mg/kg clopid)
- 0.5 mg/kg RVX, 2mg/kg clopidogrel is successful treatment
- Coadministration of apixaban/clopidogrel
- Apixaban up to 1 mg/kg PO q12h; clopidogrel 1.875 mg/kg PO q24h
- Appears safe in healthy dogs
Fibrinolytic Drugs
- Tissue plasminogen activator (tPA)
- Injectable activator of plasmin
- Rapid effect: may cause reperfusion injury
- Breaks down all clots
- Catheter-delivered
- May be superior
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Description
Explore the critical concepts of thrombosis and thromboembolism in veterinary medicine. This quiz covers diagnosis, symptoms, and the implications of thrombosis in animals. Test your knowledge on conditions such as obstructive shock and associated organ dysfunction.