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Khokhar et al. Mini-invasive Surg 2022;6:2 https://dx.doi.org/10.20517/2574-1225.2021.97 Page 7 of 19

Figure 2. Transcatheter valve embolization complicated by aortic dissection. (A) Aortic embolization of an ACURATE neo transcatheter
valve was managed by using an inflated balloon to retract the device into the aortic arch. (B) The re-positioning maneuver caused an
infolding of one of the upper stabilizing arches of the valve frame (red arrow). (C) This resulted in a type B aortic dissection (blue star),
which was conservatively managed.

incidence of severe coronary overlap [64-67] . However, the impact of commissural alignment on the
subsequent risk for coronary obstruction remains to be evaluated.

Prior to valve deployment, prophylactic placement of a coronary guidewire with or without an undeployed
stent can be considered [68,69] . Following valve deployment, if coronary obstruction ensues or coronary flow is
reduced, then the stent can be retracted and implanted halfway between the proximal coronary artery and
THV as per the “chimney” or “snorkel” technique [Figure 3] . To avoid stent under-expansion or
[70]
deformation, a stent with a high radial strength should be used followed by high-pressure post-dilatation,
with intravascular ultrasound (IVUS) used to evaluate for adequate stent expansion. If post-dilatation of the
THV is required, then a simultaneous kissing balloon inflation of the THV and coronary stent can be
performed. During ViV-TAVI, angiographic assessment may not be sufficient to decide whether stent
implantation is required. In this setting, IVUS can be used to guide decision making by identifying specific
markers of CO .
[71]

When utilized, the chimney technique is associated with good mid-term follow-up and a low incidence of
stent thrombosis of < 1% [68,69] . Given that a portion of the stent protrudes into the aorta and is unlikely to
undergo reendothelialization, prolonged dual anti-platelet therapy (DAPT) therapy should be considered.

An alternative to chimney stenting is the bioprosthetic aortic scallop intentional laceration to prevent
iatrogenic coronary artery obstruction (BASILICA) technique to split either native or bioprosthetic aortic
valve leaflets prior to TAVR implantation in order to maintain blood flow into the coronary sinus [72,73] . The
procedure involves intentional laceration of the leaflets using radiofrequency energy delivered to a
[74]
guidewire suspended between two guiding catheters . The procedure requires specific devices and
equipment with in-depth pre-procedural MSCT analysis to identify the optimal candidates for
BASILICA [73,75-77] . The recently reported results of 214 patients from the BASILICA registry are promising
with procedural success, defined as successful BASILICA traversal and leaflet laceration without mortality,
coronary obstruction, or emergency intervention, achieved in 86.9% of patients . Similar favorable results
[78]