Question of the Day

These signs in a Friesian stallion are most consistent with aortic rupture. Large ruptures result in sudden death with no premonitory signs. More common are smaller ruptures that cause this presentation (cough, edema, low-grade fever, mild colic/anxiety) for days to weeks prior to sudden decompensation and death.

Rupture in Friesians occurs most often in thoracic aorta near the ligamentum arteriosum. There is likely a genetic factor as this location is specific to, and more common, in this breed (especially stallions, average age four years). Rupture can also lead to an aortopulmonary fistula, which can cause signs similar to pneumonia preceding death.

Aortic rupture in non-Friesians is uncommon, usually near the sinuses of Valsalva, and most common in breeding stallions.

Dx: Ruling out other causes and echocardiographic findings (difficult to see location in Friesians). There is no treatment or preventive.

Ploeg et al. cover the topic well in “Thoracic aortic rupture in horses” in Equine Vet J.2017 May;49(3):269-274.