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Annibali et al. Mini-invasive Surg 2022;6:12 https://dx.doi.org/10.20517/2574-1225.2021.101 Page 7 of 16

[51]
An increased risk of embolization has been documented by placing a larger prosthesis in an Epic Supra .
[53]
In addition, SVD is more rapid if the THV is not fully expanded .
Furthermore, the VIVID registry has developed a TAVR ViV calculator that can calculate the expected
[14]
PPM at the end of the procedure, available at http://valveinvalve.org .

All of the factors that jointly result in a high post-procedural gradient are summarized in Table 1.

BIOPROSTHETIC VALVE FRACTURE
In addition to the higher THV implantation techniques, another technique that can be used in the case of
high post-procedural gradient is the bioprosthetic valve fracture (BVF). BVF has been proposed as a
technique to increase the true ID of the THV to allow either a larger THV or a better expanded THV to be
[12]
implanted in order to optimize hemodynamic performance . However, not all stented valves are prone to
fracture. As demonstrated by bench tests, Abbott Trifecta and Medtronic Hancock II valves cannot be
fractured [54,55] [Figure 2]. Sutureless and stentless valves are also not eligible for BVF but can be subjected to
balloon valve remodeling (BVR) by overexpansion . BVF is performed using a high-pressure,
[12]
noncompliant balloon, such as the Atlas Gold (BARD Peripheral Vascular, Tempe, Arizona, USA) and
[56]
TRUE balloon (BARD Peripheral Vascular), that is chosen 1 mm smaller than the size of the prosthesis .
Using a 60 mL syringe plus an indeflator assembly connected with a high-pressure three-way stopcock,
under rapid ventricular pacing, the syringe is quickly emptied to inflate the balloon, then switched to
cranking the indeflator to achieve high-pressure inflation .
[57]
Although BVF can be performed before or after TAVR ViV, most are performed after TAVR. While BVF
prior to TAVR facilitates implantation of a SE valve with less sizing mismatch and confirms successful
fracture prior to implantation, it may also cause hemodynamic instability due to severe acute aortic
regurgitation and the need for post-dilation to optimize hemodynamics . BVF after TAVR ViV, instead,
[12]
may ensure greater THV expansion and reduce the risk of hemodynamic instability due to acute severe
aortic regurgitation after fracture with the risk of possible injury to the prosthesis leaflets e with unknown
long-term effect on THV durability [12,58,59] . Possible complications of BVF include hemodynamic instability,
THV migration, coronary artery obstruction, annular rupture, THV damage, leaflet tearing, accelerated
degeneration, and debris displacement .
[54]

The pros and cons of performing BVF before or after transcatheter valve implantation are resumed in
Table 2.

To address the problem of annular fracture, a new surgical bioprosthesis (Inspiris Resilia, Edwards
Lifesciences, Irvine, CA) was made with a peculiar zone in its frame which allows expansion via a BVR
mechanism. A cobalt-chromium alloy wire makes the valve able to expand more during ViV TAVR with
[60]
the possibility of being able to implant a larger TAVR . Despite everything, however, some patients may
benefit more from a surgical reintervention with annular enlargement or replacement techniques; the main
factor to consider being the patient’s life expectancy .
[61]
TAVR-IN-TAVR AND FUTURE PERSPECTIVES IN YOUNG PATIENTS
With the release of the PARTNER (Placement of AoRtic TraNscathetER Valves) 3 and Evolut Low Risk
trials, TAVR procedures will increasingly include younger and low-risk patients, and this could lead to an
issue regarding the future management pathway for patients with aortic stenosis [62,63] .