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Page 2 of 13 Mauri et al. Mini-invasive Surg 2022;6:49 https://dx.doi.org/10.20517/2574-1225.2022.34

INTRODUCTION
Transcatheter aortic valve replacement (TAVR) can be considered as the treatment of choice in patients
with severe symptomatic aortic stenosis (AS) at prohibitive or high surgical risk and as an alternative to
surgical valve replacement (SAVR) in patients at lower risk .
[1]

The growing of elderly population in Europe and US has increased the prevalence of AS over the last
[2]
decades ; furthermore, positive results of clinical trials in patients at intermediate/low risk and the
[1]
evolution of device technologies are expected to lead to treating a larger number of patients both young and
elderly with more comorbidities [Figure 1].
Patients undergoing TAVR can be considered by themselves at higher risk of thrombotic events for
advanced age and comorbidities.

The currently available transcatheter aortic bioprostheses include different types of stents that work as a
support for a xenograft tissue with three leaflets of porcine or bovine pericardium.

As for coronary stents, an endothelization of the struts usually occurs within one month; however, this
process is not present at the level of struts far from the aortic vessel wall, with a potential increased risk of
embolic events related to this “incomplete endothelization”. Furthermore, thrombosis can occur at the level
of the leaflets .
[3]

Therefore, peri- and post-procedural antithrombotic therapy is mandatory to prevent ischemic events, but
its optimal regimen is still a matter of debate.

Table 1 reports the current recommendation of European and American guidelines for antithrombotic
therapy after TAVR.

Briefly, based on a recent European position paper and the 2021 European guidelines, patients not requiring
long-term oral anticoagulant therapy (OAC) and without recent coronary stent implantation (< 3 months)
should be treated with single antiplatelet therapy (SAPT), aspirin (ASA), or clopidogrel; if there is an
indication for OAC, a vitamin K antagonist (VKA) or a direct oral anticoagulant (DOAC) should be
continued with no addition of single antiplatelet therapy (SAPT) .
[1-4]
The American guidelines consider ASA 75-100 mg/daily as a reasonable treatment after TAVR without an
indication for OAC (Class IIa); however, in patients at low risk of bleeding, dual antiplatelet therapy
(DAPT) (ASA 75-100 mg/daily plus clopidogrel 75 mg/daily for 3-6 months) or a VKA with a target
international normalized ratio (INR) of 2.5 for at least three months may both be considered after the
[5]
procedure (Class IIb) .

THROMBOTIC AND BLEEDING RISK AFTER TAVR
The main adverse thrombotic events occurring in patients undergoing TAVR are stroke, myocardial
infarction (MI), and bioprosthesis valve thrombosis.

The incidence of cerebrovascular accidents ranges in different studies from 0% to 5% , with a higher rate
[6]
reported within the first months after the procedure . Early events (< 1 month after procedure) are usually
[7]
related to the embolization of debris from the aortic valve or the aortic wall . Later events are more likely
[8]