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Page 10 of 12 Verolino et al. Vessel Plus 2018;2:17 I http://dx.doi.org/10.20517/2574-1209.2018.32

device technology are needed before considering TAVI as a reasonable treatment option for pure AR.

PATIENTS WITH DEGENERATIVE BIOPROSTHETIC SURGICAL VALVES: THE VALVE IN VALVE
STRATEGY
As previously reported, TAVI is a useful procedure for the treatment of patients with native AS judged to
have high/intermediate surgical risk [20,45,46] . However, over the last years, another “off-label” use of TAVI is
also emerging in practice: the so-called “valve in valve” (VIV) [47,48] . Bioprostheses are known to have a lim-
[49]
ited durability, degenerating in a period of about 10-20 years . Although reoperation (“redo” surgery”) is
considered the gold standard treatment for this population, it represents a procedure associated with high
[50]
risk of morbidity and mortality. Maganti et al. observed a poor 5-year survival (67% ± 5%) in a cohort of
patients aged 75 years or older who underwent redo valve surgery. According to these findings, transcatheter
aortic VIV implantation has emerged as a viable and less-invasive technique to be used in this setting and to
obviate the need for reoperation. Despite being a technique still in progress, performed especially in special-
[51]
ized centers, a worldwide register is now available (Global Valve-in-Valve Registry) , aiming to evaluate
the effectiveness and clinical results of this technique in a wide cohort of patients. Before the creation of this
register, previous studies investigating the VIV technique included only a small number of cases and were
therefore limited in providing conclusive results. Several technical aspects have to be considered in VIV-
TAVI for a failing surgical bioprosthesis such as different radiopaque markers and different implantation
techniques. Moreover, some complications, also potentially life threatening and dangerous, such as elevated
postprocedural gradients and ostial coronary obstruction, have been reported anecdotally and sporadically,
during this type of procedure [52,53] . This registry started in December 2010, with a total of 38 participating
centers (Europe, North America, Australia etc.). The register contains data and procedural results from the
mentioned centres that have experience of TAVI with the use of both balloon and self-expandable devices.
Preliminary results were reported including 202 patients with degenerated bioprosthetic valves (aged 77.7
[51]
± 10.4 years; 52.5% men) . Bioprosthesis mode of failure was stenosis (n = 85; 42%), regurgitation (n = 68;
34%), or both (n = 49; 24%). Two devices have been implanted: Medtronic CoreValve® (n = 124) and Edwards
SAPIEN® (n = 78). Procedural success was achieved in 93.1% of patients. Device malposition occurred in
15.3% of cases whereas ostial coronary obstruction was observed in 3.5% of patients. Post-procedural valve
maximum and mean gradient were 28.4 ± 14.1 mmHg and 15.9 ± 8.6 mmHg respectively; about 95% of pa-
tients developed ≤ +1 degree AR. All-cause 30-day mortality was 8.4%, whereas, 1-year follow-up showed a
survival rate of 85.8%.

These preliminary data emerging from the Global Valve-in-Valve Registry allows us to consider the VIV
strategy a possible alternative to conventional redo surgery in patients with degenerated bioprosthetic valves.
Device malposition, ostial coronary obstruction, and post-procedural aortic stenosis remain important con-
cerns against the routine application of this procedure. Thus, other studies and longer follow-up are needed
to confirm its safety and efficacy in clinical practice.

CONCLUSION
TAVI may be considered as “first choice” and not as last chance in many patients with AS. TAVI has
emerged as the standard of care in inoperable/high risk patients whereas several randomized trials have
demonstrated similar results of TAVI compared with SAVR also in the intermediate/low risk subset. More-
over, the feasibility and safety of TAVI has been suggested also in patients with aortic bicuspid valve, pure
AR and degenerative bioprosthetic surgical valves. Importantly, a careful risk assessment through surgical
scores (STS, EuroSCORE etc.) is crucial, but other variables need to be considered such as frailty profile and
specific anatomical elements (hostile chest, porcelain aorta). These factors are relevant for procedural success
and long-term survival, but not included in the conventional scores possibly leading to underestimated risk
classification. Surely improved procedural and technical experience, associated with an enhanced healthcare