SVD in last generation TAVR

Are devices improving?

As we have been talking about in several publications here on thevalveclub, the indication for TAVR has been undergoing great expansion after publications about its use in patients at low surgical risk. Therefore, questioning the durability of prostheses is essential to understand the age group that can benefit from the implant.

It is current in the literature that, with the technological gain, bioprostheses could reach a much higher durability than what we see today, further expanding its use and indication.

Is this happening though?

Recent cohorts are being studied for both SVD (Structural Valve Degeneration) and thrombosis. What we see is that there is still a relative limitation of durability in small prostheses (<20mm) and in cases of use of TAVR prostheses such as Valve-in-Valve. The reason for this is that these cases develop greater hemodynamic stress than the others do, leading to inexorable wear of the leaflets and accelerated bioprotective degeneration.

According to the most recent definition of SVD, in addition to the traditional degeneration with calcification, we can find an episode of thrombosis that by itself does not configure SVD, but can provide an increased calcium deposit, therefore, lead to the permanent immobility of leaflets, with configuration of SVD. Thus, thrombosis research could show us which cases would have a greater chance of progressing with degeneration.

Even with the information that the use of oral anticoagulants reduces the risk of thrombosis and prosthesis dysfunction, the incidence of this event is still low in patients who have implanted TAVR and are using dual antiplatelet therapy (DAPT). At this point, putting the risk and benefit of bleeding and thrombosis in the balance is crucial to choose properly the treatment to be instituted. It is worth remembering here that the use of oral anticoagulants in TAVR has been shown to increase mortality when compared to DAPT. This is another detail for the cardiologist to put on this delicate scale.

Currently, the recommendation for the use of oral anticoagulants in TAVR is limited to cases of proven thrombosis, even if subclinical and its use leads to a reduction in gradients, with significant improvement in hemodynamic parameters. Here we require your attention to the cases of infra-annular prostheses that present greater gradients than the supra-annular ones. Being aware of this can prevent an inadequate diagnosis of subclinical thrombosis and inadvertently start an oral anticoagulant.

In summary, so far we do not have this technological upgrade to be calm about SVD and thrombosis, especially in cases of small prostheses or Valve-in-Valve.

Suggested literature:

1 – Rheude T, Pellegrini C, Cassese S, et al. Predictors of haemodynamic structural valve deterioration following transcatheter aortic valve implantation with latest-generation balloon-expandable valves. EuroIntervention. 2020 Feb 20;15(14):1233-1239.

 

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