Operative procedures and strategy
We previously reported our standard operative procedure and strategy for
mitral valve surgery with reduced left ventricular
function10. Briefly, the procedures were performed
through the median sternotomy approach, and cardiopulmonary bypass was
established with ascending aortic and bicaval cannulations. In the re-do
cases, cardiopulmonary bypass was established with peripheral
cannulations as needed. Concomitant coronary artery bypass grafting was
performed in an on-pump beating fashion where possible with the aim of
reducing cross-clamp time. Other procedures were performed under cardiac
arrest with antegrade, intermittent, cold-blood cardioplegia.
Our strategy for selecting repair
or replacement was changed at the beginning of 2014, based on the
results of a randomized, controlled study and the good results obtained
with chordal-sparing mitral valve replacement.11,12Before 2014, our first choice of mitral procedure was mitral plasty even
in cases with reduced cardiac function. Mitral valve replacement was
chosen when left ventricular diastolic diameter was >70 mm,
in re-do cases or in hemodialysis cases for which reverse remodeling was
not expected. Since 2014, we have selected chordal-sparing mitral valve
replacement as the first-line procedure in secondary mitral
regurgitation with reduced cardiac function. Mitral plasty was performed
for younger patients (early 60s or younger), and when left ventricular
diastolic diameter was <60 mm.
Apart from this strategy, we have chosen mitral valve replacement for
patients for whom a poor prognosis was anticipated, as in patients with
advanced age, high frailty, or other critical conditions.
In mitral valve plasty, an undersized annuloplasty ring was used, and
whether the mitral sub-valvular apparatus procedure was performed was
determined by the surgeon based on the echocardiographic findings,
including tethering height >10 mm13 or
the location of papillary muscles. Our sub-apparatus procedures consist
of papillary muscle re-suspension to the mitral anterior annulus with
CV3 or CV4. When papillary muscle heads were separated, the anterior and
posterior heads were combined together with the re-suspension stitch,
then re-suspended toward the saddle horn, as previously
reported.14
In mitral valve replacement, valve leaflets were tucked in the annulus
with stitches securing the prosthetic valve, sparing all chordae.
This study was approved (Approval No: NHC2021-0330-11) by the
institutional ethics committee on March 30th, 2021,
and the need to obtain written consent from patients was waived because
of the retrospective study design.