Treatment of feline aortic thromboembolism  (F.A.T.E.)

Note: Over 90% of cases are associated with underlying heart disease.

1. Caged rest

• Warm comfortable bed – without hot external heat source

2. Analgesia
The pain of this condition should not be underestimated and analgesia is of paramount importance.

• Morphine (0.1mg/kg q6-12hrs), oxymorphine, fentanyl, pethidine or butorphanol.

3. Anticoagulation with heparin

• Heparin primarily prevents further thrombus formation
• A suggested dose of heparin in cats is 250iu/kg i/v every 8 hours. The dose should be adjusted to maintain the activated partial thromboplastin time (aPPT) at the top end of the normal range or at least 1.5 times the baseline level.  [Protamine sulphate can be administered to counteract haemorrhage due to heparin overdose (dose at 0.25 mg protamine per 100 iu of heparin). Overdosage with protamine will cause an irreversible haemorrhagic condition.]

4. Management of congestive heart failure

• Usually requires chest radiography to diagnose.
• Oxygen supplementation – without manual restraint or stress
• Thoracocentesis to relieve dyspnoea due to pleural effusion, if present
• Low-dose frusemide (1mg/kg q8-12 hr) - if there is pulmonary oedema.

5. Treatment of systemic signs of hypoperfusion (hypothermia)

• Fluid therapy (eg. 2 - 4 mls/kg/hr) for dehydrated cats  – that are not in congestive failure.
• Nutritional support if anorexic

6. Thrombolytic therapy

• As yet, of unproven value in feline aortic thromboembolism and complications include: reperfusion injury, hyperkalaemia, haemorrhage, metabolic acidosis.
• Streptokinase (90,000 iu over 30 minutes, then 45,000 iu/hr for 3 to 6 hours) and urokinase, but these drugs must be used within 2 or 3 hours following an embolic event (if you use these drugs, I would be very interested in your experience)

Not recommended

• Acepromazine – may exacerbate hypotension
• Beta blockers – may enhance peripheral vasoconstriction

Prophylaxis

• Aspirin 5 –  30mg twice a week (eg. ¼ to ½ of a 75mg tablet twice a week)
• Low molecular weight heparins - need to be injected twice daily
• Plavix (clopidogrel 75 mg)- ¼ tablet daily. This may be combined with twice weekly aspirin. This is available from pharmacies or most veterinary drug companies.  

Prognosis

• As a guideline: 1/3rd will die, 1/3rd will be euthanased and 1/3rd will survive to discharge – of these the recurrence rate is very high.
• Poor prognostic indicators are: hypothermia and bradycardia (<140/min)