michael s
(Michael S)
#1
42 When to repair the mitral valve?
Robin Kanagasabay
Mitral valve repair has been popularised by Carpentier and
others and now represents a recognised option in the treatment of
mitral valve disease. Advocates argue that all mitral valves should
be considered for repair first, and only those that are not suitable
should be replaced. Mitral valve repair offers real advantages over
replacement, chiefly low operative risk (around 2%1,2), avoidance
of the risks of long term anticoagulation (in patients who are in
sinus rhythm), very low risk of endocarditis, and probably better
long term preservation of left ventricular function. The last aspect
may not be as clear cut as once thought as techniques to replace
the mitral valve while still preserving the sub-valvular chordal
apparatus, which is so important in regulating ventricular
geometry, may offer many of the advantages once held to be the
sole preserve of repair techniques.^3 A potential disadvantage of
mitral valve repair is the less certain surgical outcome of the tech-
nique which relies on a greater degree of judgement, and the
possible need for future redo surgery in around 10% of cases.^4
The standard use of annuloplasty rings has improved results and
reduced the need for redo surgery, but not to zero, and this point
needs to be discussed with patients prior to choosing an
approach.
Different valvular lesions are more or less amenable to mitral
valve repair, and require that different techniques be employed:^5
Increased leaflet motion (Carpentier type II)
The patient with pure mitral regurgitation due to either a floppy
myxomatous valve, or posterior leaflet chordal rupture represents
the easiest and most successful case and the valve can be repaired
by quadrangular resection of the posterior leaflet. Repair of
anterior leaflet prolapse is a more complex undertaking and
requires either a transfer of chordae from the posterior to the
anterior leaflet, or the use of synthetic chordae. An alternative is
to suture the free edges of the two leaflets together at their
mid-points creating a double orifice valve, the so called Alfieri
bow-tie repair.
