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Mauri et al. Mini-invasive Surg 2022;6:49 https://dx.doi.org/10.20517/2574-1225.2022.34 Page 9 of 13

[36]
one year compared to VKA .

Therefore, evidence supporting DOAC over VKA in AF patients undergoing TAVR is still lacking. As
expected, in patients with AF and recent PCI undergoing TAVI, the choice of optimal antithrombotic
regimen is even more complex. In the absence of direct evidence, the duration of dual therapy should follow
post-PCI recommendations. Based on individual thrombotic and bleeding risk, current guidelines
recommend the combination of DOAC plus clopidogrel with a very short period of aspirin (maximum six
months, only in patients with high thrombotic risk) .
[37]

The evidence of the best antithrombotic regimen in patients with or without indication for OAC is
summarized in Figure 2.

Valve deterioration or leaflet thrombosis
Thrombosis contributes to the deterioration of bioprosthetic valves after both SAVR and TAVR [38,39] , with
the incidence increasing over the years.

Based on the available data, a subclinical leaflet thrombosis of the bioprosthesis was detected with CT scan
in about 20%-30% at one year from TAVR, and its association with an increase in cerebrovascular events
remains controversial [10,40] .

Even if the clinical impact of HALT and RLM is questionable, selective use of oral anticoagulants should be
[1]
considered , as a lack of OAC prescription at hospital discharge after TAVR was an independent predictor
of bioprosthetic valve deterioration detected with echocardiogram .
[41]
In the French TAVI registry, a prescription of OAC at hospital discharge was associated with a reduction of
dysfunction of the bioprosthesis .
[42]

Although the prescription of OAC after TAVR seemed to improve the motion of the leaflets and reduce
their thrombosis, the controversial data for clinical events associated with this therapy, especially regarding
DOAC, require further investigation.

In a 4D-CT analysis of the ATLANTIS study presented at American College of Cardiology 2021, HALT and
RLM were lower with apixaban compared to with antiplatelets in patients without indication for OAC, but
this was not associated with better clinical outcomes . Low-dose rivaroxaban achieved similar results in the
[43]
GALILEO 4D substudy .
[44]
FUTURE DIRECTIONS
As yet explained, in some patient subsets, robust clinical trial evidence is still lacking and actual
recommendations are guided by expert opinion or findings derived from observational or small randomized
studies. Although it might be supposed that in some settings such as valve-in-valve an aggressive
antithrombotic therapy including OAC is required, it should be demonstrated in a specific randomized
study.

Furthermore, no evidence on different antithrombotic therapies based on the type of implanted
bioprosthesis (balloon or self-expandable) is available.