Feline aortic thromboembolism: sudden deterioration on day two
7-year-old Maine Coon with hypertrophic cardiomyopathy, hospitalised 20 hours ago with bilateral aortic thromboembolism. He is receiving methadone, clopidogrel and low-molecular-weight heparin; there is no pulmonary oedema. Over the last hour the hind limbs have warmed slightly, but the cat is now very dull and bradycardic.
| Parameter | Result | Reference |
|---|---|---|
| Heart rate | 110 bpm | 140–220 |
| Potassium | 8.9 mmol/L | 3.5–5.1 |
| ECG | Tall peaked T, no P waves, wide QRS | — |
| Lactate | 6.8 mmol/L | < 2.5 |
| Creatine kinase | 85,000 U/L | 50–450 |
Which treatment takes priority?
chevron_right Show answer and explanation
A. IV atropine to correct the bradycardia and improve perfusion
The bradycardia results from hyperkalaemia depressing conduction; atropine does not correct that mechanism and delays effective treatment.
B. IV furosemide bolus to increase renal potassium excretion
Kaliuresis is slow and insufficient for life-threatening hyperkalaemia, does not protect the myocardium and, in a cat without oedema, may cause hypovolaemia.
C. High-dose unfractionated heparin for a probable new thrombus
The picture does not indicate a new thrombus but reperfusion of ischaemic muscle, which releases potassium, lactate and creatine kinase into the circulation. More anticoagulation will not correct it.
D. IV calcium gluconate with continuous ECG, then insulin with glucose
Correct. This is reperfusion injury with severe hyperkalaemia. Calcium immediately antagonises the effect of potassium on the myocardial membrane, and insulin with glucose shifts it into cells. Recheck potassium and glucose every few hours.
lightbulb Key takeaway
Reperfusion injury is a major cause of death in the first days of feline thromboembolism, especially as the limbs begin to recover. Because of this risk, routine thrombolysis (alteplase, streptokinase) is not recommended. Measure potassium serially over the first 24–48 hours and avoid potassium-supplemented fluids.
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Updated: November 1, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.