Conditions or ailments that are the cause of a problem that you see - your observation.

Your vet may diagnose

Ruptured Aorta, Ruptured Aortic Aneurysm

Synonyms: Aortic Root or Aortic Ring Rupture


Ruptured aortic aneurysm is a cause of sudden death that is more common in older male horses, especially breeding stallions. It usually occurs after breeding or following intense exercise. It is most commonly caused by a congenital aneurysm of the aortic root. The rupture results in massive bleeding into the chest or abdomen.

Collapse and death usually quickly follows rupture of an aortic aneurysm or ruptured aorta, usually within a few moments. But in some cases, it may not kill the horse immediately.

What follows can look similar to any other condition that results in signs of colic, along with signs of worsening heart failure. Other vessel ruptures can also cause massive bleeding into the abdomen or chest.

All of these occur without any external bleeding.

Diagnosis is usually done at post-mortem exam. In the standing horse, diagnosis requires ultrasound echocardiography. It may be possible to use echocardiography to visualize early development of aneurysm.

There is no practical treatment for this condition at this time.

my vet's role


For the rare case that is diagnosed prior to death, heart medications may somewhat prolong life. However, the long term prognosis is poor, and these horses are a danger to handlers because of the potential for sudden collapse.

There is a variation on this condition in Friesian and Friesian cross horses in which they experience a more of a chronic state of this condition. There is likely a congenital predisposition in this breed.

my role


I might observe

You might make these observations when a horse has this condition.

Very Common
Less Common
more observations

Questions To Ask Your Vet:
  • If the horse survives, what will their quality of life be like?
  • What precautions can I take given that the horse could suddenly collapse?
  • Is there a congenital basis for this?

None known at this time. Do not breed lines of horses in which this condition has been diagnosed.

Related References:

Lavoie JP, Hinchcliff KW eds. Blackwell's 5 Minute Vet Consult: Equine. 2nd Ed. Ames: Wiley Blackwell 2008.

Higgins AJ, Snyder JR eds. The Equine Manual. 2nd Ed. Edinburgh: Elsevier Saunders 2006.

M. PLOEG, V. SAEY C. M. de BRUIJN A. GR?NE K. CHIERS et.al. Aortic rupture and aorto-pulmonary fistulation in the Friesian horse
Characterization of the clinical and gross post mortem findings in
24 cases. Equine Veterinary Journal ISSN 0425-1644
DOI: 10.1111/j.2042-3306.2012.00580.

Author: Doug Thal DVM Dipl. ABVP