Balloon expandable transcatheter aortic valve replacement

Introduction

The only balloon-expandable valve currently on the market is the Edward Sapien Heart valve manufactured by Edwards Life Sciences. This chapter will focus on the procedural techniques involved in the use of this balloon-expandable prosthesis.

Edwards sapien balloon-expandable heart valve prosthesis

The Edwards Sapien heart valve system is made up of a cobalt–chromium frame with three bovine pericardial leaflets. The frame has open upper and closed lower cells to enhance geometry and ensure an ultra-low-profile delivery, and also has a skirt incorporated at its inflow portion and outer sealing skirt to reduce paravalvular leaks. The current valve, Sapien 3, is delivered via the Edwards Commander delivery system for a transfemoral approach. This is a 14-16F eSheath compatible system with optimal positional control, and its dual articulation enables coaxiality and fine control of valve positioning. The transapical approach typically uses the 18F Edwards Certitude delivery system, and this has an integrated pusher to streamline the procedure and an ergonomically designed handle for ease of use ( Fig. 8.1 ).

Edwards S3 valve

The valve is simple to deploy and has shown good durability and function in both trial and real-world experience. The valve comes in four sizes: 20 mm, 23 mm, 26 mm, and 29 mm, suitable for most annular dimensions. The delivery sheath can be actively flexed, and this is beneficial, particularly in horizontal aortas.

Patient selection

There are several important considerations when choosing the balloon-expandable transcatheter aortic valve replacement (TAVR) system over a self-expanding system. First, the current S3 system requires 16F transfemoral access. Some of the self-expanding prostheses, including the Evolut R, use an in-line sheath, which requires 14F access and may be more suitable for patients with smaller iliofemoral or alternative access sites. The minimal vessel dimensions are detailed later. The sheath can be actively flexed when it is advanced, and this is particularly useful in the case of horizontal aortas.

Second, the balloon-expandable TAVR requires rapid ventricular pacing during valve deployment. A short pacing run is required and is well tolerated by the majority of patients; however, patients with very poor left ventricular (LV) function or significant pulmonary hypertension may not tolerate rapid pacing well. These patients may therefore be more suited to a self-expanding valve.

Finally, the Edwards S3 has leaflets at the annular position and so has a smaller effective orifice area than supra-annular valve designs such as the CoreValve. For larger valves, this is less important, as postoperative gradients will be low, but in patients with small annular dimensions, particularly in the case of valve-in-valve TAVR, a supra-annular valve may be more suitable. In practice, postprocedure transaortic gradients using the Edwards S3 valve are low, so this is more of a theoretic than a practical concern in the vast majority of patients.