Cusp overlay implantation technique – planning step-by-step

The cusp-overlay method aims to implant the self-expandable device higher than in former ways without device pop-out upon release and it reduces pacemaker rates significantly.

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Summary

Unlike balloon-expandable valves which require a coplanar projection with 3 cusps, additional steps are taken when implanting a self-expandable valve, for example, Corevalve/Evolut-R/Pro-Platforms. A coplanar projection by overlapping the right coronary cusp (RCC) and left coronary cusp (LCC) offers several potential advantages.
Finally, the cusp-overlay method aims to implant the self-expandable device higher than in former ways without device « pop-out upon release and it reduces pacemaker rates significantly.

In cusp-overlay view you can:

eliminate the parallax of the delivery catheter
observe the deployment in true coplanar view
work with a shorter visual distance for Corevalve/Evolut-Platforms to engage the non-coronary cusp (NCC) and LCC

The problem

Various methods have been suggested for determination of the optimal projection for transcatheter aortic valve replacement (TAVR). Balloon-expandable transcatheter heart valves (THVs) are commonly centred and deployed in a perpendicular view of the aortic valve annulus, with the RCC projected between NCC and LCC.
Self-expanding THVs, however, engage the aortic valve from the outer aortic curvature and are deployed from the NCC toward the LCC.
Even with new generation self-expandable THV-Devices such as Corevalve/Evolut-Platforms, the occurrence of conduction disturbances requiring pacemaker implantation is a significant concern. In contrast to classical implant-views (3 cusps), cusp-overlay technique promises the visualization of the real implantation depth.

Principal idea

The cusp-overlay method aims to define optimal fluoroscopic projections for TAVR with a self-expandable device. Optimal projection is generated by overlapping the RCC to the LCC. The non-right commissure is displayed in the centre of the fluoroscopic image, allowing the interventionalists to deploy the device relative to the membraneous septum and hence the conduction system below the atrioventricular node.

Almost always cusp overlay view results in right anterior oblique (RAO) and caudal (CAU). The view isolates the NCC to provide accurate assessment of deployment depth and elongates the view of the left ventricular outflow tract (LVOT).

At the level of NCC, the correct implantation plane for deployment of TAVI achieves higher implants with more control and lower pacemaker rates by less interaction with conduction system. The NCC nadir is better visualized, allowing higher valve deployment with a lower risk of « pop-out ».

In patients with challenging body habitus such as obesity, an RAO, caudal view may reduce fluoroscopic image quality, and certain extreme RAO, caudal angles may not be possible to create the cusp-overlap view.
In those instances, we perform e.g. Evolut - TAVI using a 3-cusp view or overlapping the NCC and the RCC in an LAO cranial view. Contemporary implant techniques of modern self-expandable TAVI-platforms (e.g. Evolut/Acurate/Navitor) using cusp-overlay technique also for commissural alignment aspects for coronary artery cannulation after TAVI.

Material needed

Planning of the mentioned cusp-overlay technique is possible with dedicated software tools like 3mensio valves software (Pie Medical Imaging; Maastricht, the Netherlands) using multi-detector computed tomography (MDCT) data set.

Method step-by-step

Step 1 - Preprocedural Evaluation and assessment of MDCT Scan

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Step 2 - Implantation technique in RCC/LCC cusp overlay technique

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Video 7 - Control in 3 cusp view before final release

Points of specific attention

obligatory is a cross-check in 3cusp (true coplanar) view for implantation depth in LCC area before final release
in 3 cusp-view, eliminate the parallax of the delivery catheter
keep the calcium burden and its distribution (known from the MDCT reconstruction) in every TAVI – step in mind
assessment of aortic delivery catheter positioning in LAO

A word from the reviewer - Alexander Wolf

The cusp overlay technique is helpful not only in achieving a higher implant with the Corevalve Evolut platform - and therefore it can help to reduce pacemaker rate post-TAVI, but it also plays a role in commissural alignment with various self-expandable transcatheter aortic valve systems.