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

Intra-procedurally, failure of rapid ventricular pacing during valve deployment can lead to a sudden
[54]
subsequent migration or embolization of the THV . Therefore, stability of the pacing system should be
confirmed prior to valve crossing and deployment. Following valve deployment, caution should be taken
during retraction of the device nose-cone as well as the jailed pigtail catheter, which should be removed
with the aid of a 0.035" wire.

Management of transcatheter valve embolization
Deep ventricular embolization nearly always requires open surgical repair. Implanting a second THV to
trap the embolized valve prior to surgical conversion may limit the duration and complexity of the
subsequent surgical intervention . In contrast, aortic embolizations can be managed interventionally, with
[55]
surgery reserved for cases complicated by aortic injuries such as dissections or perforations [Figure 2]. If the
extent of aortic embolization is minimal, the first THV can be fixed by a second THV implanted in the
[56]
appropriate location .

In more extensive embolization, repositioning maneuvers using snares or an inflated valvuloplasty balloon
[57]
can be used to grasp, move, and deploy the embolized valve at an ectopic location . If embolization is
complicated with coronary obstruction, then immediate proximal retraction of the device should be
performed. Care must be taken while manipulating the THV to avoid aortic injury and dissections,
especially with certain SEV which have more prominent outflow portions [Figure 2]. During repositioning
of an embolized BEV, the ventricular guidewire should always be maintained within the valve to prevent
inversion of the valve and potential flow obstruction. The preferred location for deployment is in the
descending aorta, distal to the left subclavian artery taking care to avoid any major aortic branches.
However, in tortuous, heavily diseased or calcified aortas where the risk of aortic injury during re-
positioning maneuvers is high, deployment at a more proximal position can be considered and was found to
not be associated with an elevated stroke rate . Implantation of a covered or uncovered stent within the
[49]
embolized valve leaflets can be undertaken to fixate the valve against the aortic wall. Mid-term follow-up of
ectopically implanted THVs suggests there is a minimal risk for further migration or subsequent vascular
functional [49,56,58] .

CORONARY OBSTRUCTION
The incidence of coronary obstruction is < 1% for native valve TAVR and increases up to 3.5% for valve-in-
valve (ViV-TAVR) [59-61] . It presents acutely intra-procedurally with hypotension, ischemic electrocardiogram
(ECG) changes, and usually involves the left coronary ostium . Delayed coronary obstruction can occur up
[59]
to one-year post TAVR and is more commonly seen following ViV procedures or with use of a SEV .
[62]
Strategies for high-risk coronary obstruction
High-risk anatomical features for coronary obstruction (CO) include low coronary ostia (< 10 mm) and the
presence of narrow shallow aortic sinuses . For ViV-TAVR, additional factors include the presence of a
[59]
stentless or stented valve with externally mounted leaflets and a virtual transcatheter distance of less than
4 mm [Figure 1] [61,63] .

In patients found to be at high risk for CO, SAVR should be considered. If not feasible due to the operative
risk of the patient, then multiple strategies can be considered. Use of a partially or fully recapturable THV
(Evolut-R/PRO, Portico, LOTUS) or a THV with a favorable open-celled design (ACURATE neo,
NAVITOR) may be advantageous. Newer devices with unique leaflet grasping mechanisms (Jena and
Engager) may theoretically be advantageous in a ViV setting. Techniques to achieve commissural alignment
with the Evolut and ACURATE neo platforms have been described and can successfully reduce the