Page 39 - Journal of Structural Heart Disease Volume 1, Issue 3

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Original Scientific Article
implanted during rapid right ventricular pacing with- in the 28-mm Physio® mitral annuloplasty ring with equal proportions within the left ventricle and the left atrium, using fluoroscopy and transesophageal echocardiography guidance.
The first transcatheter tricuspid valve-in-ring im- plantation was described by Mazzitelli et al. [31]. They reported the case a of a combined off-pump ante grade trans-atrial implantation of a 26-mm Sapien® valve within mitral and tricuspid annuloplasty rings (Physio® 28-mm and 26-mm respectively) through an anterolateral minithoracotomy in a 61-year-old wom- an. The direct trans-atrial approach was considered to be ideal to treat both valves at the same time. The pa- tient was extubated after 24 hours and discharged on the ninth postoperative day with satisfactory valvular function (minor paravalvular tricuspid regurgitation). Shuto et al. [32, 33] described the first completely percutaneous valve-in-ring implantation using the Melody® device in a mitral ring. Via standard vascular access and transseptal techniques, they successfully deployed the Melody® valve into the mitral position from the venous circulation in five sheep, without complication. Although there was a conformational change noted in the implanted Melody® valves from “round” to “oval”, there was no perivalvular leakage and only trivial to mild central regurgitation was ob- served. These results were confirmed in another ani- mal study using 4 distinct types of annuloplasty ring.
The complete percutaneous approach was recent- ly used to perform a tricuspid VIR implantation in a 64-year-old female who underwent placement of a mitral valve homograft with a #34 Physio® ring (Ed- wards Lifesciences, Irvine CA, USA) in the tricuspid position in whom echocardiography revealed severe tricuspid stenosis with a mean gradient of 16 mm Hg with mild tricuspid regurgitation [34]. A transcathe- ter 26 mm Edwards SAPIEN® valve was placed in the tricuspid position through a femoral vein approach, resulting in near normalisation of tricuspid valve gra- dient. Prosthesis size was estimated by computed to- mography, intracardiac echocardiography, and finally by balloon sizing during the procedure. Furthermore, a pre-stenting technique was used to ensure appro- priate coverage of the valvular orifice and make valve positioning easier although the presence of a com- plete rigid Physio® ring may theoretically facilitate
prosthesis apposition, and reduce the risk of device embolization or paravalvular leak. A similar case was recently reported using the same approach and the same transcatheter 26 mm Edwards SAPIEN® pros- thesis [35].
For transcatheter VIR implantations, the dimen- sions of the tricuspid valve annulus are better approximated by the commercially available SAPI- EN® valves (up to 26 mm in diameter) than the Mel- ody valves (maximum expandable diameter 22 mm). However, because of the conception of the Edwards valve (made of manufactured three equal pericardial leaflets), the device should be open as close as possi- ble to its nominal diameter and as round as possible to allow enough flow and closing volume and thus avoid functional stenosis or leak. Melody valve is more versatile and can be open to various diameters and configuration without impinging the valvar func- tion. However expansion of Melody valves to diame- ters larger or equal to 25-mm has been associated in with valvular incompetence and device embolization when implanted in mitral rings[33]. Nevertheless, the valve-in-ring approach for atrioventricular valves may extend the functional life of the surgical substrates in a manner analogous to Melody® and Sapien® valve treatment for dysfunctional surgical conduits in the pulmonary position.
Percutaneous Treatment of Native Tricuspid Valves
In native tricuspid valves, implanting a trancath- eter prosthesis remains challenging because of the absence of a stiff region to anchor the valve, and the lack of fluoroscopic markers and the difficulties to precisely assess annulus measurements (due to the absence of tricuspid surgical markers such as ring or bioprosthesis). However, strategies have been de- veloped to perform not only percutaneous tricuspid valve replacement whether in orthotopic or hetero- topic position, but also a conservative transcatheter tricuspid valvuloplasty.
Transcatheter Orthotopic TV Replacement
In 2005, Boudjemline et al. [36] designed a new device intended to be implanted percutaneously in native tricuspid valves and published the first study
Jalal, Z. et al.
Transcatheter Tricuspid Valve Therapies