Which valve is least affected in Rheumatic fever?(

Ref: R Alagappan - Manual of Practical Medicine 4th Edition.pg no:147 Valve Involvement in Rheumatic Hea Disease Mitral valve alone 50% Aoic valve alone 15-20% Mitral and Aoic valves together 35-40% Mitral, Aoic and Tricuspid valves 2-3% Pulmonary valve is viually never involved. In RHD, mitral valve is most commonly involved followed by involvement of the aoic valve as the pressure gradient across the mitral valve is the greatest, followed by that across the aoic valve. So, the mitral valve is more susceptible to develop pathological changes than the aoic valve