Transcatheter aortic valve implantation is an
increasingly widespread method in the treatment
of severe aortic stenosis.[
8] However, the primary
uncertainty regarding the long-term follow-up of
TAVI is its durability. Advancements in TAVI
valve design and deployment methods may enhance
long-term durability.[
9] With the increase in longterm
durability, we expect an increase in redo-TAVI
procedures in the near future.
The Valve Academic Research Consortium-3
identifies four primary mechanisms which contribute to the dysfunction of bioprosthetic valves for TAVI:
(i) endocarditis; (ii) structural valve deterioration
(SVD); (iii) valve thrombosis; and (iv) non-SVD.[10]
The recommendation for redo-TAVI versus
surgical aortic valve replacement (SAVR) in patients
with SVD and non-SVD depends on multiple criteria.
Recent data from the United States indicate that the
30-day mortality rate for redo-TAVR is lower than
that of SAVR.[11,12]
In their study, Şentürk et al.[7] showed that the
number of true SVD was low in patients who underwent
TAVI, confirming that the durability of TAVI valves
was high. In our study, the indications for redo-TAVI
were mainly due to paravalvular leak rather than
SVD. In patients with paravalvular leak compared to
those with SVD, the need for redo-TAVI has occurred
earlier. This also highlights the necessity for the first
TAVI procedure to be optimal for durability.
While preparing for a redo-TAVR procedure,
it is essential to take into careful consideration the
structure of the dysfunctional first TAVI valves.
These TAVI valves differ in terms of the form and
size of the metal stent frame, as well as the location
of the leaflets inside the frame.[13]
Inserting a new TAVI valve into a defective
TAVI valve leads the leaflets of the first valve to remain in the open position. This basically
transforms a portion of the initial valve into an
enclosed cylindrical conduit. The vertical dimension
of the enclosed cylinder is usually known as the
neoskirt height. The neoskirt height is strongly
influenced by the particular stent frame type and
the precise positioning of the leaflets. The height of
a neoskirt has a direct influence on the likelihood of
possible coronary blockage.[14-17] Several parameters,
including as TAVI valves design, implant depth,
and TAVI valve choice for redo-TAVR, increase
the possibility of coronary blockage. Performing
cardiac CT is a standard procedure to assess the
risk of coronary occlusion while managing a failing
bioprosthetic valve with TAVI.
Currently, there is insufficient evidence to inform
TAVI valve selection for redo-TAVR. The choice of
TAVI valve device for redo-TAVR depends on the
characteristics and location of the first TAVI valve,
the underlying reason of failure, and its surrounding
anatomical structure.[18-20]
There is a limited number of empirical evidence
available on the practice of redo-TAVI in real-life
scenarios. TAVI accounted for 0.46% of the 133,250
TAVI operations in the Medicare database from
2012 to 2017. In addition, it included 0.33% of the
63,876 procedures in the redo-TAVI worldwide
registry, which are the two largest published series.
In selected patients, redo-TAVI is usually safe and
successful, with minimal procedural complications
and significant relief in symptoms. Survival
rates at 30 days are similar to those reported
in other valve-in-valve transcatheter aortic valve
replacements (TAVRs) performed in patients with
intermediate-to-high surgical risk. The mortality
rate ranges from 2.9 to 6.0%, the stroke rate ranges
from 1.4 to 1.8%, and the pacemaker rate ranges
from 4.2 to 9.6%.[13] However, the survival rate
at one year is lower, ranging from 13.5 to 22%.[13]
This could be due to the higher risk of mortality in
this particular population, which affects the overall
outcomes.[11-14,19]
Although TAVI can be performed in degeneration
of surgical aortic valves, initial TAVI preserves
the patient's surgical chances and provides the
opportunity to perform percutaneous procedures
in the future.[21] Younger patients undergoing open
SAVR may be encouraged to start using bioprostheses
more, instead of mechanical valves in the near future, given the availability of this effective technique for
replacing a malfunctioning surgical bioprosthesis. It
is well-known that the mortality of redo surgery is
high compared to redo-TAVI.[22,23]
The main limitation to this study is that it has a
single-center and retrospective design with a relatively
small sample size. Of note, although different surgeons
performed the first and second TAVI procedures, all
were experienced in TAVI.
In conclusion, with the widespread use of
TAVI procedures and increased valve durability,
patients are followed for longer periods of time
currently. Some patients require reintervention due
to valve degeneration or severe aortic regurgitation.
Redo-TAVI can be performed in these patients.
Redo-TAVI procedure is feasible and successful.
However, further large-scale, long-term, prospective
studies are required to further assess its effectiveness
and safety.
Data Sharing Statement: The data that support the
findings of this study are available from the corresponding
author upon reasonable request.
Author Contributions: Idea, critical review: K.D.;
Design, writing the article: A.A.B.; Control/supervision:
H.D., D.K.; Data collection: S.K., O.Ç., H.O.; Analysis
and/or interpretation: O.Ç., H.O.; Literature review: H.D.,
A.A.B.
Conflict of Interest: The authors declared no conflicts
of interest with respect to the authorship and/or publication
of this article.
Funding: The authors received no financial support for
the research and/or authorship of this article.
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