When should we operate to relieve mitral regurgitation?

There are three circumstances when surgery is required for mitral regurgitation:

1. To save life in the acute case
   Sudden mitral regurgitation following rupture of degenerative chordae tendineae, papillary muscle rupture, or endocarditis may be very poorly tolerated. The surgeon may be presented with a patient in pulmonary oedema, even ventilated, and then an operation may be the only way to save life.
2. The symptomatic patient with chronic mitral regurgitation
   Surgical relief of regurgitant valve lesions can bring dramatic relief. The decision is not always easy but a sensible appraisal of the risks and benefits is what is needed. If there is a tolerably good ventricle, and substantial regurgitation to correct, then the benefits are likely to outweigh the risks. The degree of left venticular dilatation to be tolerated before surgery is required has reduced. In general, it is now suggested that a left ventricular end-systolic dimension (LVESD) of 4.5cm is a sensible threshold for “perhaps not waiting any longer”.
3. Mitral regurgitation and the dilated ventricle
   The third scenario is the most difficult. Some patients seem to tolerate mitral regurgitation quite well with a large ventricle ejecting partly into a large, relatively low pressure left atrium. The left ventricle may ot be as good as it appears because the high ejection fraction is into low afterload. If you continue to wait the risks only get higher. Any increasing tendency in LVESD is ominous and the onset or progression of symptoms should prompt operation to protect the future.