Can you tell us about fluoroscopic “lucent line” deployment?

Gilbert Tang, MD: It’s a great topic and is actually quite controversial. “Lucent line” refers to a radiolucent (“lucent”) line on the Sapien 3 valve (Edwards Lifesciences). Someone posted on Twitter that they saw a space on the bottom part of the Sapien 3, used it as a reference to deploy the valve, and found that it can help achieve a higher implant to avoid a pacemaker. I did not know what the lucent line was all about until this discussion on Twitter, and people started asking, "Do you see it every time? Is it reproducible?" No one seemed to be able to give a clear answer.

Subsequently, there were two papers published, one by Cleveland Clinic, using lucent lines of reference in a right anterior oblique (RAO) caudal projection to demonstrate that the pacemaker rate is lower using that technique. Then, the Vancouver group with Janar Sathananthan also showed that with the cusp overlap view, you could achieve a higher implant and reduce the pacemaker rate. However, Edwards recommends that the Sapien 3 be deployed in a coplanar view or a three-cusp view, not in a cusp overlap view or an RAO caudal view.

We wanted to determine the percentage of time that the lucent line is actually visible when using the manufacturer-recommended view because no one had yet looked into that. Also, if you do see the lucent line, what is the percentage of time that there is actually a coaxial deployment of the Sapien 3, meaning that you see the lucent line because there is no parallax on the valve and you don't see any parallax on the valve either after deployment. 

In our study looking at over 1100 cases, we found that the lucent line was only visible about 64% of the time. Among those cases where the lucent line was visible, only in slightly over two-thirds was a coaxial deployment actually achieved. In the remaining one-third, a noncoaxial deployment was achieved. For those cases where the lucent line was not visible, almost 99% of the time, there was not a coaxial deployment.

Our conclusion was that first, the lucent line is not visible 100% of the time when the Sapien 3 is deployed in a coplanar manufacturer-recommended view. Second, we looked at the implant depth of the 3 most common groups we found (lucent line visible + coaxial implant; lucent line visible + noncoaxial implant, and no lucent line visibility + noncoaxial implant). If you have a visible lucent line and a coaxial implant, the implant depth ended up statistically deeper than the other two scenarios. We weren't doing lucent line-based deployment at the time; in this study, we were only looking at whether the lucent line was visible or not during valve deployment. The lucent line doesn't really help, because it is not always visible during valve deployment — almost 35% of the time, you have to use another method to visualize and plan for the implant depth. We also found that whether the Sapien 3 valve is coaxial or noncoaxial after deployment made no difference, at least for the in-hospital rate, for paravalvular leak, pacemaker, or vascular complications. There is no difference in hemodynamic performance whether or not the valve is coaxial after deployment.

Our message is that visualizing the lucent line is not necessary to achieve a high Sapien 3 implantation because, number one, it is not always visible and, number two, there are other factors involved that affect the final implant depth. The good thing is that there is no impact on procedural outcome or in-hospital outcomes.

Find more: TVT Newsroom (With a Special Focus on TAVR)

Find Dr. Tang’s presentation slides here.