Page 457 - Read Online

Sengupta et al. Vessel Plus 2020;4:40 I http://dx.doi.org/10.20517/2574-1209.2020.55 Page 3 of 7

IMAGING-BASED ASSESSMENT OF THV ORIENTATION
Accurate imaging is essential for preprocedural planning. To assess the risk of commissural misalignment
and severe coronary overlap, our group pioneered the technique of determining THV orientation using
[10]
multi-detector computed tomography (MDCT)-fluoroscopy co-registration . Briefly, we begin by
measuring the en-face angle between the left main and right coronary arteries using MDCT. Next, using
the 3Mensio Valves software (Pie Medical Imaging version 9.1, Maastricht, Netherlands), we capture
the THV orientation in the three-cusp coplanar fluoroscopic view and co-register it onto our coplanar
MDCT axial images. We can then superimpose a virtual image of either the SAPIEN 3 THV (Edwards
Lifesciences LLC, Irvine, CA, USA) or the Evolut THV (Medtronic Inc., Minneapolis, MN, USA) over the
axial MDCT annular and sinus of Valsalva images derived from the 3Mensio Valves software. This allows
[11]
us to determine the degree of overlap between the neo-commissures and the coronary ostia . Note that
the use of various third-party software systems introduces the risk of operator bias that has to be taken into
consideration when performing the aforementioned analyses.

IMPACT OF THV TYPE AND CONTEMPORARY RESULTS
We have previously used the aforementioned co-registration technique to assess the relationship between
THV deployment orientation and commissural alignment as part of the ALIGN-TAVR (Alignment of
Transcatheter Aortic-Valve Neo-Commissures) study. Here, > 30%-50% of the 828 patients who underwent
TAVI from 2016-2019 (483 SAPIEN 3, 245 Evolut, and 100 ACURATE-neo) had overlap with at least
one coronary artery. More importantly, commissural alignment was unaffected by initial deployment
orientation of the SAPIEN 3 THV, but was significantly improved by specific initial orientations of the
Evolut and ACURATE THVs . The nuances between the two main types of commercially available THVs
[12]
in the context of the ALIGN-TAVR and other contemporary studies are discussed below.

SAPIEN 3
The balloon-expandable SAPIEN 3 valve can have one commissure crimped at the 3, 6, 9, or 12 o’clock
orientation relative to the delivery catheter to track the initial deployment orientation. In the ALIGN-
TAVR study, commissural alignment was not improved by crimping the SAPIEN 3 THV at each of the
[12]
aforementioned orientations . We speculated that this may be due to the flexibility of the delivery catheter
as it courses through the aorta. Fortunately, the unassuming profile of SAPIEN 3 stent frame renders
commissural alignment less pertinent for coronary reaccess as wires and catheters can engage the coronary
ostia above and through the top row of the stent frame. Coronary access can nevertheless be challenging in
certain cases where the SAPIEN 3 stent frame protrudes beyond a narrow STJ [13,14] .

[15]
Similar findings were reported by Rogers et al. in their study of 137 low surgical risk patients from
the LRT (Low Risk TAVR) trial (NCT02628899) who underwent balloon-expandable TAVI. Using post-
TAVI MDCT analysis, the authors found that 9%-13% of patients displayed high-risk alignment due to the
valve stent frame extending distal to the coronary ostia and an obstructive commissural post. Similar to
the ALIGN-TAVR study, commissural alignment was not significantly influenced by intentional crimping
of the transcatheter valve. The THV stent frame protruded beyond the STJ in 21% of patients, and the
THV-STJ margin was < 2 mm in 13% of patients. Patients with THV-STJ margin < 2 mm were deemed
[15]
anatomically unsuitable for redo-TAVI given the excessive perceived risk of coronary obstruction .
Despite limited generalizability, the findings from this anatomic simulation corroborate the results from
our pilot angiographic study that show that redo-TAVI may not be possible in > 20% of SAPIEN 3 patients
[16]
and more than half of those with unfavorable aortic root anatomy (sinus height < THV height) .
Evolut
Commissural alignment is particularly important for facilitating coronary reaccess following Evolut TAVI
since this supra-annular valve extends above the STJ and coronary ostia. The Evolut THV has a unique “Hat”