Discussion.
Reoperation for mitral bioprosthesis failure is associated with
increased mortality and morbidity.1 According to the
recent data from the Society of Thoracic Surgeon (STS), American College
of Cardiology and Transcatheter Valve Therapy Registry including 1529
patients with a mean STS score of 11.1% and a mean age of 73 years,
TMViV for mitral bioprosthesis failure is an attractive
alternative2. Indeed, procedural success (96.8%) was
high and all-cause mortality at 30 days was 5.4%. The transseptal
approach became more and more dominant during the inclusion period
compared to transapical approach (overall 86.7% of transseptal
approach) and is associated with a lower 1-year mortality rate (15.8%
versus 21.7%, p=0.03). Table 1 summarizes the largest series reporting
TMViV for degenerated bioprosthesis2–9 considering
procedural success, rate of transseptal approach, Edwards THV sizes,
post procedural mean gradient, rate of LV outflow tract obstruction and
all-cause mortality.
With respect to our case, we clearly favored the transseptal over
transapical approach considering the reduced LVEF. Technically, the use
of the Agilis steerable transseptal sheath is recommended to provide
enough support to advance the stiff guidewire into the LV. When using
the usual SL0 transseptal sheath (Abbott Vasc), the pigtail repeatedly
moved out from the LV while advancing the stiff Safari guidewire.
In the largest registry from Whisenant et al, a mean gradient of 6.9
mmHg was found at one year for valve sizes of 26 and 29 mm, which is
similar to our patient, but superior to what we can expect after
conventional surgery. The SAPIEN S3 THV is FDA approved for TMViV for
mitral bioprosthesis since June 2017. However, unanswered questions
remain with respect to the elevated residual mean gradient and its
effect on valve durability and potential valve
thrombosis10. Additional studies are required to
define the optimal anticoagulant therapy in the absence of atrial
fibrillation as well as long term outcomes.