Aneurysm of the ductus arteriosus in a heifer

The paper describes clinical, radiological, ultrasonographic and pathological findings of an aneurysm of the ductus arteriosus in a heifer. The pathogenesis of the present ductus arteriosus aneurysm, unusually characterised by a thick internal, multiple layer of blood embedded in fibrin and fibrotic organisation, is unclear. It is possible that the aneurysm developed at birth or shortly after and increased in size with time without compromising the general condition of the animal. Although the origin of the thick internal layer is unclear, stagnant blood may have led to fibrin deposition, which was subsequently organised into fibrotic tissue. A solid mass derived through fibrin organisation can compress the mediastinic vessels and block the venous return, causing oedema and alterations of the cardiorespiratory physiology.