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Annibali et al. Mini-invasive Surg 2022;6:12 https://dx.doi.org/10.20517/2574-1225.2021.101 Page 5 of 16

[13]
stents .

Another technique developed to prevent coronary obstruction is the Bioprosthetic Aortic Scallop
[29]
Intentional Laceration to prevent Iatrogenic Coronary Artery obstruction (BASILICA) procedure . Since
the first one in 2017, dozens of procedures have been performed worldwide with satisfactory results. The
valve leaflets are lacerated via an electrified guidewire, thereby facilitating blood flow to the coronary artery.
Pending data regarding the BASILICA procedure in TAVR ViV, those currently available in the literature
demonstrate excellent success rates and low mortality rates in high-risk patients for coronary obstruction
undergoing TAVR over native valve [30-32] .

After THV implantation, the leaflets of the degenerated surgical prosthesis will be tilted up, thus creating a
covered cylindrical stent through which it will be impossible to pass a coronary catheter. The height of this
barrier, previously called neoskirt [33-36] , will be determined by the length of the degenerated surgical
prosthesis leaflets. Several factors must be considered when assessing the risk of coronary artery re-access:
[12]
the size of the STJ, the location of the coronary ostia in relation to the neoskirt and the type of the THV .
A coronary artery obstruction risk classification was created in 2019 from the VIVID registry. Through an
anatomical classification of the aortic root and valve leaflet location to determine the possible need for the
BASILICA procedure, three types of patients were identified: Type I with aortic valve leaflets below the
coronary ostium; Type II with leaflets above the ostium in the presence of wide (IIA) or effaced sinuses
(IIb); and Type III leaflets above or very close to the STJ with wide STJ/sinuses (IIIA), with effaced sinuses
(IIIB), and with narrow STJ (IIIC). According to this algorithm, the BASILICA procedure should be
[37]
considered in case of a VTC < 4 mm as in Types IIB, IIIB, and IIIC .
Regarding TAVR-in-TAVR procedures, Tarantini et al. proposed an algorithm based on the anatomy of
[33]
the aortic root and its interaction with the different THVs to predict the risk of acute coronary occlusion
and feasibility of future coronary access after TAVR-in-TAVR. Through a combined CT and coronary
angiography analysis, they identified the risk plane (RP) as the level below which the passage of a coronary
catheter will be impossible after the second THV and identified different types of scenarios based on the
patient’s anatomy and the first THV implanted. Coronary artery re-access will be possible in Type 1, with
coronary ostia below the RP, and Type 2a, with coronary ostia below the RP but with the valve-to-aorta
distance (VTA) > 2 mm, particularly if the THV type used for ViV TAVR has an open-cell design .
[38]
Instead, Type 2b, with coronary ostia below the RP and VTA < 2 mm, is associated with a high risk of
coronary obstruction . The use of a THV with a low frame is certainly an advantage over supra-annular
[33]
THVs with higher frames and higher asymmetric commissures. During implantation, proper commissure
alignment, possible with some partially orientable devices as Evolut (Medtronic, Minneapolis, MN, USA)
and ACURATE (Boston Scientific, Marlborough, MA, USA), with the surgical bioprosthesis or the first
THV will be critical because misalignment could make re-access to the coronary ostia impossible [12,39] . All
factors related to coronary obstruction are resumed in Figure 1.

PROSTHESIS-PATIENT MISMATCH AFTER VIV TAVR
Prosthesis-patient mismatch (PPM) occurs when the EOA of a normally functioning prosthesis is too small
in relation to the patient’s body size, causing abnormally high postoperative gradients. Severe PPM is
2
defined as an indexed effective orifice area (iEOA) < 0.65 cm /m following aortic valve replacement . The
[40]
2
PPM is relatively frequent following SAVR in patients with small anatomies and becomes a problem to
consider during the planning process of patients with degenerated small aortic bioprosthesis. Female sex is a
strong clinical predictor of PPM after SAVR. In addition, older age, hypertension, diabetes, renal failure,