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Page 2 of 11 Avvedimento et al. Mini-invasive Surg 2022;6:24 https://dx.doi.org/10.20517/2574-1225.2021.143

INTRODUCTION
Within the last two decades, transcatheter aortic valve implantation (TAVI) has revolutionized the
treatment strategy for symptomatic severe aortic stenosis (AS), representing a less invasive alternative to
surgery. Based on the results of several large-scale randomized clinical trials (RCTs), TAVI indications have
[1,2]
now expanded from inoperable to low surgical risk patients . As TAVI expands to younger and low-risk
patients with longer life expectancies, the need for post-TAVI coronary access and reintervention for failing
[3]
transcatheter heart valve (THV) is expected to increase . In this context, THV orientation during initial
deployment has gained importance to determine the difficulty of future coronary re-access after TAVI.
Prior to recent investigations, commissural alignment of THVs appeared to be random and not
reproducible during TAVI, contrary to surgical aortic valve replacement (SAVR), in which the resection of
native leaflets and strict commissural alignment of bioprosthetic valves with native commissures results in
no interference with coronary ostia .
[4]
Neo-commissural alignment during TAVI was first described by Dumonteil et al. in 2013. Despite its
[5]
demonstrated usefulness, then-available THVs and delivery systems did not allow interventionalists to get
consistent and precise commissural alignment. The reason to aim for commissural alignment in TAVI,
especially in younger patients where lifetime management becomes important, is that, with misalignment
and the potential presence of a THV commissural post facing a coronary ostium, coronary access would
have to be performed around the physical barrier of the commissural post. In the case of redo-TAVI
evaluation, leaflet management techniques such as BASILICA cannot be performed when a commissural
post faces a coronary ostium.

In light of these considerations, optimizing commissural alignment in TAVI should be pursued as this may
facilitate subsequent coronary access, avoiding severe overlap with the THV commissures, and potentially
redo-TAVI. This review aims to provide an overview of available evidence for neo-commissural alignment
and strategies to achieve more anatomic valve implantation further.

COMMISSURAL ALIGNMENT IN TAVI: RATIONALE AND IMPLICATIONS
In a recent analysis, Fuchs and colleagues reported that strict alignment was obtained in only about one-
fifth of patients undergoing TAVI . The degree of alignment depends on the angle between coronary
[4]
orifices and bioprosthetic commissures, aiming to obtain an angle between 0° and 15°. Misalignment,
instead, is graded according to deviations from the native commissures in mild (from 15° to 30°), moderate
(from 30° to 45°), and severe (from 45° to 60°), with coronary overlap defined as an angular distance from
one of the commissural posts to a coronary ostium below 20°. The degree of misalignment is defined by the
risk of overlap between neo-commissures of the THV and native coronary ostia [Figure 1]. Furthermore,
despite a lack of correlation with the difference in transvalvular gradient or coronary filling, a moderate or
greater commissural misalignment has been associated with a significantly higher rate of mild central aortic
[4]
regurgitation .

RCTs comparing TAVI vs. SAVR have not reported rates of neo-commissural alignment, and available
TAVI devices do not contain specific instructions. Moreover, given that aortic root and coronary anatomy
differ in each patient, the development of algorithms and patient-specific implantation technique to obtain
commissural alignment during TAVI would be important to improve reproducibility and ease of use.

Commissural alignment during TAVI should be achieved to facilitate future coronary access and redo-
TAVI. As recently reported by Tarantini et al. , commissural alignment increases the feasibility of selective
[6]
coronary angiography after TAVI with supra-annular devices. Furthermore, recent evidence suggests that