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Page 8 of 12 Verolino et al. Vessel Plus 2018;2:17 I http://dx.doi.org/10.20517/2574-1209.2018.32

major complications associated with TAVI should be considered such as the need for permanent pacemaker
(PMK) (25.9% at 30 days in the SURTAVI trial and 18.5% at 1 year in the OBSERVANT trial) and the devel-
[34]
opment of paravalvular leaks, with an incidence of about 1% according to the recent literature findings .
Probably with increased operators’ experience, longer learning curve and newer generation devices, these
complications could be reduced. However, rehospitalization and mortality rates of patients undergoing PMK
after TAVI were not higher compared with those who did not develop this complication. Moreover, only a
small percentage of patients treated with TAVI has undergone a new procedure (valve-in-valve) or shifted
[35]
to open surgery due to the development of large paravalvular leaks . On the other side, two important
elements arise from all these studies in favor of TAVI: reduced hospitalization time (in days) and lower inci-
dence of new onset atrial fibrillation (AF). Length to stay in hospital is significantly shorter for TAVI patients
[36]
than SAVR: in particular, 4 vs. 10 days was reported by Garcia et al. and 8.9 vs. 12.9 days in the NOTION
[31]
[33]
trial . Similar results were observed also in the OBSERVANT registry (8.8 vs. 12.6 days, P < 0.001) . In this
century where spending review is a real concern, reduction of average length of stay in hospital is an impor-
tant issue; obviously, no less important is an earlier patient’s return to home with an overall positive advan-
tage for public health (healthcare infection, lodging). On other hand, AF is the most frequent rhythm dis-
ease with several aspects that significantly deteriorate patient quality of life and long-term prognosis. Several
studies showed that SAVR is burdened with a higher incidence of AF compared with TAVI; in the NOTION
study, about 59.4% of patients developed AF after 1 year from surgery compared with only 21.2% of patients
[31]
[28]
undergoing TAVI (P < 0.001) . Leon et al. confirmed these findings in the PARTNER 2 trial reporting an
incidence of new onset AF of 11.3% and 27.3% in the TAVI and SAVR groups, respectively. In the SURTAVI
[29]
trial, the incidence of AF was higher after SAVR (43% after 30 days) than in the TAVI group .
Finally, another important issue that should be considered for TAVI as a routinely procedure especially in
low-risk population is valvular degeneration. Actually, poor data are available to define the durability of
prostheses in young patients with life expectancy > 20 years. Otherwise, there is not yet a clear definition
of “prothesis degeneration”. One of those currently used, according to Valve Academic Research Consor-
tium (VARC 2) definition, is based on specified echocardiographic criteria: mean aortic valve gradient
≥ 20 mmHg, EOA (effective orifice area) ≤ 0.9-1.1 cm , DVI (Doppler velocity Index) < 0.35 m/s, and/or mod-
2
[34]
erate or severe prosthetic valve regurgitation . Thus, a specific trial is needed to evaluate long-term out-
comes in a selected population with low-risk profile. Surely TAVI may be considered even as first option in a
population with intermediate-risk and, where patient agrees, also in a low risk profile.

PATIENTS WITH BICUSPID AORTIC VALVE
Bicuspid aortic valve (BAV) is one of the most common congenital valve abnormalities, occurring in 0.7%-
2% of the general population. BAV is related to a higher valve shear stress, favouring leaflet calcification and
[37]
degeneration and AS and/or aortic regurgitation (AR) development . BAV has been considered for a long
time as a relative contraindication to TAVI, first of all for the higher expected risk for relevant AR. Further-
more, the unfavorable anatomy of BAV may interfere with the appropriate positioning and expansion of the
prosthetic valve, theoretically increasing the incidence of procedural complications as well as decreasing the
efficacy and durability of the prosthetic valve [8,20] .

[38]
Different studies were conducted to evaluate the relative benefits of TAVI in patients with BAV. Bauer et al. ,
within the German TAVI Registry, prospectively enrolled 1424 patients with severe AS undergoing TAVI
from January 2009 to June 2010. They compared TAVI outcomes in patients with BAV (n = 38, 3%) and those
with tricuspid aortic valve (TAV) (TAV; n = 1357, 97%). They observed that PMK implantation occurred
more frequently in patients with TAV (17% vs. 35%, P = 0.02), whereas a greater rate of relevant AR was ob-
served among patients with BAV after the transcatheter procedure (25% vs. 15%, P = 0.05). Of note, despite
the higher risk for relevant AR among patients with BAV compared with those with TAV, 30-day and 1-year
[38]
mortality rates were similar in both subsets of patients . A systematic review and meta-analysis conducted