TAV-in-SAV: transcatheter heart valve (THV) positioning
Accurate positioning of the prosthetic valve during transcatheter aortic valve implantation (TAVI) is essential for achieving good procedural results. As with TAVI for native aortic stenosis, the optimal fluoroscopic angle for implantation should be chosen. This section explores the different THVs involved and examines how to best position them for optimal results within a failed surgically implanted bioprosthetic valve…
This is achieved by lining up the fluoroscopic markers, particularly the sewing ring, along a single plane. Understanding the construction of the surgical bioprosthesis is axiomatic10. The recently developed Aortic VIV Application Aortic valve in valve app provides a very useful guide for THV positioning in available bioprostheses. In stented bioprostheses, the sewing ring is the most rigid structure and provides the anchor for THV implantation. For supra-annular bioprostheses, the Edwards SAPIEN and the CoreValve should be positioned 15-20% and 4 mm below the lowest fluoroscopic part of the stent, respectively (Figure 5) (Movie 55). For intra-annular bioprostheses, the Edwards SAPIEN and the CoreValve should be positioned 15-20% and 4 mm below the sewing ring, respectively (Figure 5) (Movie 56). Intraprocedural transoesophageal echocardiography is strongly recommended to aid positioning in cases with stentless valves or for stented valves with radiolucent sewing rings or when the leaflets are non-calcified or regurgitant. Stable guidewire position and coaxial implantation of the THV are essential for accurate positioning. Ventricular pacing should be considered for patients with greater than mild bioprosthetic regurgitation. The Edwards SAPIEN valve is probably best inflated gradually and slowly, as small adjustments can be made during deployment to optimise positioning. Cautious initial deployment of the CoreValve is essential as further positioning of the THV is extremely difficult or even impossible once firm contact has been made with the frame of the surgical valve. Ventricular pacing or breath-hold may also facilitate deployment. Second-generation TAVI systems that are recapturable and repositionable will hopefully reduce the incidence of THV malposition34.
Figure 5. Intra- and supra-annular bioprostheses