Aortic valve stenosis associated with valvular heterotopic ossification with extramedullary haematopoiesis in a horse

Abstract

SummaryThis report describes a case of functional aortic stenosis with heterotopic ossification in the aortic valve of a 20‐year‐old Thoroughbred mare. The aortic valve pathology was associated with aortic outflow obstruction, dilation of the left ventricle and left atrial enlargement ultimately leading to pulmonary hypertension and clinical signs of right‐sided heart failure. Histopathological examination demonstrated the presence of haemopoietic cells within the calcified aortic valve leaflets, which is a rare finding, and revealed myxomatous degenerative changes in the mitral valve and multifocal areas of fibrous tissue within the myocardium. There is marked similarity between this case and the human condition of calcific aortic valvular disease (CAVD), which is the most common reason for valve replacement surgery. In this case, we report the clinical and pathological features in this first reported case of equine aortic valve stenosis.