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Khokhar et al. Mini-invasive Surg 2022;6:2 https://dx.doi.org/10.20517/2574-1225.2021.97 Page 9 of 19

facilitate an interventional solution to the CO. If, however, the situation cannot be resolved percutaneously,
[50]
then emergent open-heart bypass remains the mainstay of treatment .
PARAVALVULAR LEAK
Post-TAVR paravalvular leak (PVL) arises due to incomplete device apposition against the native aortic
[1-3]
annulus. Residual moderate-severe PVL is a strong independent predictor for mortality . Even mild PVL,
[6]
which was observed in 29.4% and 33.9% of subjects at one year post-TAVR in the PARTNER3 and
[7]
Evolut low-risk trials, respectively, was associated with elevated mortality at two and five years post
TAVR [81,82] . Therefore, particularly for younger patients undergoing TAVR, the aim should be to achieve
minimal to no residual leak.

Minimizing risk of paravalvular leak
Accurate pre-procedural CT analysis should prevent valve under-expansion and can also be used to identify
high-risk features such as heavy annular and/or leaflet calcification, which may lead to valve under-
expansion or malpositioning [Figure 1] . In subjects where heavy calcification is expected to increase the
[83]
risk of significant paravalvular leak, newer generation valves should be considered. The Sapien 3 ultra
(Edwards LifeSciences), Evolut Plus (Medtronic), and ACURATE neo 2 (Boston Scientific) valves all have
an additional sealing skirt and the NAVITOR (Abbott) valve has a dynamic sealing skirt added to minimize
PVL. Therefore, detailed pre-procedural CT evaluation combined with appropriate device selection plays a
key role in minimizing PVL .
[84]

Management of paravalvular leak
When faced with post-implant aortic regurgitation in the catheterization laboratory, it is important to
differentiate between PVL and guide wire-induced central aortic regurgitation. Retraction of the guide wire
or exchanging the stiff wire for a softer pigtail catheter may clarify the diagnosis. Currently, the gold-
standard for evaluation of PVL remains echocardiography , however transthoracic visualization may be
[85]
sub-optimal and the use of intra-procedural transesophageal echocardiography is diminishing as minimalist
TAVR procedures with conscious sedation are being widely adopted [20,86] .

Conventional aortography, although convenient, is only helpful at the extremes of AR severity .
[85]
Quantitative video densitometry may provide a better evaluation of AR severity, but as with simple
aortography it is limited in its ability to distinguish between central or paravalvular regurgitation. Several
hemodynamic indices have been proposed [Table 1], with the AR index (calculated as LVEDP-DPB/SBP)
[87]
being the most widely adopted . However, hemodynamic indices may be limited by heart-rate variations,
[88]
atrial fibrillation, and altered hemodynamic conditions due to sedation and/or anesthesia. Therefore, in
cases of doubt, intra-procedural echocardiography with color and doppler evaluation is still
recommended .
[85]
Treatment of PVL
Balloon post-dilatation represents the main stay of treatment with balloon sizing based on pre-procedural
CT measurements of the annulus. The use of repeated aggressive balloon dilatation to correct PVL must be
balanced against the risk of subsequent aortic injury, annular rupture, or stroke, especially in patients with
heavy or nodular calcification. When faced with this scenario, the degree of pre-TAVR AR can be a useful
guide as to how aggressively post-dilatation should be performed. Patients with mixed aortic valve disease
have more compliant ventricles and can tolerate post-procedural AR better than those with smaller, stiffer
ventricles .
[89]