1 | INTRODUCTION
Open heart surgical use of a transcatheter aortic valve implantation
(TAVI) prosthesis for mitral stenosis (MS) with severe MAC appears to
decrease the risk of atrio-ventricular disruption following
decalcification and circumflex artery injury, and simplifies the
procedure1,2. And this procedure has no risk of
systolic anterior motion of the anterior mitral valve leaflet (AML)
compared to percutaneous transcatheter mitral valve implantation (TMVI)
, because we can resect the AML in open surgery. A potential problem
with this procedure that should be addressed is a left ventricular
outflow tract (LVOT) obstruction by the prosthesis, especially by the
felt strip at the prosthesis1. This problem may
especially occur when pre-operative LVOT is reduced by myocardial
hypertrophy, which is usually observed when an associated aortic
stenosis (AS) is present.
2 | CASE DESCRIPTION
A 74-year-old man presented with New York Heart Association class Ⅱ due
to AS and MS.
Echocardiography showed severe MS with a mean pressure gradient (PG) of
12 mmHg and a mitral valve (MV) area of 0.99 cm2(Figure. 1A). The left ventricle (LV) was hypertrophic and the LV
ejection fraction was 70%. AS was also severe and the aortic valve (AV)
area was 0.74 cm2. MAC was severe as shown on computed
tomography (CT) (Figure. 1B). The pre-operative aortomitral angle was
110゜(Figure. 1C), so the risk of LVOT obstruction was
high3. The width of the pre-operative LVOT in the
direction of placing the TAVI prosthesis was 20.3 mm (Figure. 1D). The
extra space after performing TMVI becomes neo-LVOT. We can estimate
post-procedural LVOT obstruction taking measurement of neo-LVOT at the
baseline CT scan.
After a median sternotomy on cardiopulmonary bypass with cardioplegic
cardiac arrest, the calcified AV was resected through an aortotomy. The
aortic annulus was small and a 19-mm AVALUS valve sizer (Medtronic,
Minneapolis, MN, USA) was suitable. The left atrium was opened parallel
to the interatrial groove. We resected the A2 valve to prevent anterior
MV protrusion in the LVOT and secondary LVOT obstruction. We sewed
anchor sutures around the mitral annulus (2-0 coated braided polyester
sutures with pledgets) in places where needles exhibited no resistance
around or across calcifications. These sutures were used to fix the
final position of the TAVI prosthesis once inflated. We measured the
mitral annulus using valve sizers of mitral mechanical valve and we
chose a valve that was exactly the same size as the annulus. As
previously described2, after washing a 26-mm
Sapien-Edwards AV (Edwards Lifesciences, Inc., Irvine, CA, USA), felt
strip sewn to the Sapien to cover the polyethylene terephthalate portion
(Figure. 2A). The prosthesis was mounted upside down on the short
delivery catheter. A Safari XS (Boston Scientific, Natick, MA, USA) was
passed into the catheter to avoid injury of the LV. The balloon was
inflated, the valve was deployed under direct visualization (Figure.
2B). During that step, it was necessary to assess the position of the A1
and A2 parts of the mitral annulus on the felt strip to reduce the
amount of covered stent into the LVOT. Usually the width of the felt
strip is approximately 1 cm and a residual 5-6 mm width in the atrial
side is likely to avoid LVOT obstruction. Then, the valve was fixed in
its position by passing the previous anchor sutures across the bottom of
the Sapien and tied with the Corknot device (LSI Solutions, Victor, NY,
USA) to prevent valve migration. These sutures, in our opinion, also
reduced paravalvular leaks (PVL) (Figure. 2C). After we closed the left
atrium, we replaced the AV with a 19-mm AVALUS (Medtronic).
Visualization through the aortic annulus confirmed that only a limited
part of the felt strip was positioned into the LVOT, thus obstruction of
the LVOT was not likely to occur (Figure. 2D). After we closed the
aorta, the cross-clamp was removed after 96 min. While weaning from
cardiopulmonary bypass, we temporarily stopped the bypass flow and
checked the PG between the LV (109/12 mmHg) (needle through the
ventricular wall) and the ascending aorta (94/56 mmHg). Because the
direct pressure is higher than the pressure measured by
echocardiography, and the mean gradient measured by echocardiography
after AV replacement using AVALUS is between 10 and 15 mmHg, this
maximum PG was acceptable4. Transthoracic
echocardiography 3 month post-operatively showed no PVL at the mitral
prosthesis and confirmed no significant LVOT obstruction.
3 | DISCUSSION
Mayra et al.1reported a multicenter global registry involving the acceptable outcomes
of early experience with TMVI in patients with MAC1.
However, the 30-day and 1-year all-cause mortality rates were 25% and
53.7%, respectively. It was concluded that LVOT obstruction is the most
important and independent predictor of 30-day and 1-year
mortality5.
Although cross-clamping and cardioplegia were required, this technique
allows precise assessment of positioning along A1 and A2 of the covered
part of the TAVI and resection of A2. Indeed, these two points are
advantages in avoiding LVOT obstruction compared to percutaneous TMVI.
John-Peder et al.6 reported a case of LVOT obstruction
after trans-apical TMVI, and the patient needed for secondary surgery to
resect the A1-A2-A3 parts of the MV.
In percutaneous TMVI, a laceration of the AML may be performed to
prevent LVOT obstruction (LAMPOON procedure). Vasilis et
al.7 reported five successful cases of patients at
risk for LVOT obstruction who underwent the LAMPOON procedure and
percutaneous TMVI using the Sapien 3; however this technique does not
appear to be appropriate for calcified AML.
Patients with AS and mitral disease associated with MAC can be treated
with associated classical AV replacement and trans-atrial open heart
TMVI. During balloon inflation, this approach allows a very good
assessment of the width of the covered TAVI prosthesis positioning into
the LVOT and might play a major role in reducing the risk of LVOT
obstruction; however, more experience is needed to confirm this
preliminary result.
3 | CONCLUSION
Open heart mitral valve replacement using the Edwards-Sapien 3 for
severe mitral annular calcification (MAC) is a safe procedure, because
we don’t need to decalcify the MAC. And also, we can resect the anterior
leaflet to prevent left ventricular outflow tract obstruction and we can
deploy it under direct visualization.
Conflicts of interest
Dr L. Leroux is a proctor for Edwards Lifescience.
The other authors declare that there are no conflicts of interest.
Acknowledgments
None
Ethics statement
The authors confirm that written consent for submission and publication
of this case report.
Author contribution
SM, ST, MP, LL and LL: made major contributions to the writing of this
manuscript. All authors read and approved the final manuscript.
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Legends
FIGURE 1 A, Pre-operative transesophageal echocardiography showed
calcified MV and MAC with turbulent flow at the MV in systole. B,
Pre-operative CT showed MAC. C, Aortomitral angle was 110゜. D,
Pre-operative LVOT. The measurement is parallel to the TAVI prosthesis.
FIGURE 2 A, Felt strip sewn to the Sapien to cover the polyethylene
terephthalate portion. B, Valve implantation. C, After the valve
implantation, anchor sutures were sewn to the felt strip and tied
thereafter. D, Visualization via the aortotomy enabled us to view the
Sapien at the mitral position and there was no obstruction at the LVOT.