. Author manuscript; available in PMC: 2013 Mar 1.

Published in final edited form as: J Vet Cardiol. 2012 Feb 24;14(1):31–45. doi: 10.1016/j.jvc.2011.11.003

Table 1.

The principal criteria for the classification of myxomatous mitral valve lesions.^57,78

Lesion Grade	Nodules (Location)	Leaflets (Location)	Chordae	Valvular Competence
1	Few, small oedamatous (apposition)	Areas of diffuse opacity (basal)	Unchanged	Maintained
2	Multiple, grayish-white, coalesce (apposition)	Areas of diffuse opacity (throughout)	Unchanged	Maintained
3	Increased size, plaque- like (apposition)	Defined areas of opacity (basal)	Thickened at junction with leaflets	Some incompetent
4	Greyish white, plaque- like elevations (apposition)	Grossly distorted; ballooning overgrowth (closure line)	Thickened, can be stretched/ruptured	Majority incompetent