Mitral regurgitation means that the mitral valve is leaking. Mild tricuspid insufficiency means that the tricuspid valve is leaking, but just a very small amount.
Regurgitation: the valve does not close tightly. Therefore, as the blood flows normally from the left atrium into the left ventricle, on the systole or squeeze part of the heart beat, a portion of blood is "Regurgitated" back into the atrium.
Insufficiency in the Tricuspid valve means a leak in the valve. When they refer to my tricuspid leak, a +1-2 leak, it is because the valve is not closing tightly.
Generally you will find patients who have Mitral leaks also have some Tricuspid involvment due to equaliztion activity to offset pressures within the heart; distortions from LV hypertrophy or enlargement can also create regurgitant leaks.
Depending on age, length of time and severity, curing one problem may solve others. It is not unusual for a Tricuspid regurgitant leak to disappear after the Mitral regurgitant leak is cured. And a mitral leak can disappear or significantly be reduced if the Aortic valve regurgitant leak is fixed. Hope this helps.