2.4.3 Valvular changes
The aetiology and pathophysiology of valvular disease in the horse is very poorly understood. Myxomatous change is seen in degenerative valvular disease. It is a relatively common finding, but is not usually as extensive as in the dog. Inflamchange, with a lymphocytic and or neutrophilic infiltrate has been reported. This suggests that a form of valvulitis may be responsible for the development of valvular incompetence in some cases. Confirmation of this disease process requires further research.
If vegetative endocarditis is present, the endothelium will be broken, with extensive areas of fibrin and thrombus. Inflammatory cells, and in some cases bacteria, may also be seen. Usually endocarditis is obvious on gross examination of the valve. (See section 6.6.)