The TriCinch System (4TECH Cardio Ltd, Galway, Ireland) is a percutaneous device designed for TV remodeling, by means of a transfemoral implantation of a stainless steel corkscrew into the TV annulus at the level of the antero-posterior commissure. The corkscrew is connected through a Dacron band to a self-expanding nitinol stent. By pulling the system towards the inferior vena cava (IVC), the anchoring corkscrew remodels the antero-posterior annulus, adjustments on a beating heart under live echo guidance are possible, and when the correct level of tension is achieved, the tension is maintained by implantation of the stent in the IVC (Fig. 24.2). The stent is available in different sizes (27–43 mm in diameter, 60 mm in length) to guarantee oversizing in the hepatic region of the IVC and prevent stent migration. Extensive preclinical testing was performed with the TriCinch System in animal models, to prove the safety, technical feasibility and performance. More than 60 adult swines (40 acute and 24 chronic up to 90-days) were treated with the device through a transfemoral venous access [12]. All animals survived the acute implant, showing the feasibility and the efficacy evaluation (30 % reduction in septo-lateral TV annular dimension, significant increase in trans-tricuspid peak velocity and coaptation length). Furthermore, all the chronic animals correctly completed the follow-up period, demonstrating the safety of this type of technology in terms of stable implant into the TV annulus. The TriCinch System is currently under evaluation in the multicenter European First-in-Man PREVENT Study (Percutaneous Treatment of Tricuspid Valve Regurgitation With the TriCinch System; ClinicalTrials.gov identifier: NCT02098200), which is enrolling patients with functional TR that are suitable for transcatheter treatment. Preliminary results obtained in the first 3 successfully implanted patients showed reduction of the septolateral annular dimension that remained stable at 6-months after implantation, with sustained clinical and functional improvement [13, 14].

The Mitralign device (Mitralign, Inc. Tewksbury, USA), which was originally designed for the treatment of functional mitral regurgitation [15], has recently been used to treat functional TR by performing a transcatheter bicuspidization of the TV though the transvenous jugular approach [16]. A steerable catheter is advanced in the right ventricle across the tricuspid valve and positioned under echocardiographic guidance. An insulated radiofrequency wire is then advanced from the base of the leaflet and within the annulus, toward the right atrium in the desired position, near the anteroposterior commissure. Once the wire is through the annulus, a pledget delivery catheter is advanced over the wire from the right atrium across the annulus to the right ventricle. The steps are then repeated on the opposite anatomic site of the posterior commissure (Fig. 24.3). A dedicated plication lock device brings the 2 pledgeted sutures together, plicating the annulus and bicuspidizing the TV. Preliminary results obtained in 7 high-risk patients with symptomatic FTR have been reported. Implantion was feasible in 5/7 patients with no reported adverse events, demonstrating its safety. Tricuspid annular dimension were acutely reduced in 4/5 patients [16, 17].

The FORMA Repair System (Edwards Lifescience, Irvine, US) is a valve spacer, which is positioned into the tricuspid regurgitant orifice in order to create a platform for native leaflet coaptation. The device is delivered through subclavian venous access and is distally anchored to the RV apex. Proximal fixation is performed in a small surgically prepared pocket (as done for permanent pacemaker implantation). Preliminary results in 7 high-risk patients were recently reported. In all the patients, the device was successfully implanted without major complications, obtaining a mild-to-moderate acute reduction of TR grade. Thirty-day results, showed for 4 patients, reported clinical improvements and stable TR reduction [18].

The Millipede system (Millipede, LLC, Ann Arbor, Michigan) involves the placement of a tricuspid annular ring with an attachment system via either minimally invasive surgical or percutaneous access to remodel the native tricuspid annular shape and diameter. It is repositionable and retrievable before deployment [10]. No updated preclinical feasibility or safety data are currently available and the company has changed its focus to concentrate on the mitral valve.

Since the surgical edge-to-edge repair for the tricuspid valve, the clover technique, was associated with satisfactory results at mid-term follow-up [19], the implantation of the MitraClip device (Abbott, Abbott Park, Illinois) in the tricuspid position is currently under investigation. First-in-man use of MitraClip to treat TR was reported in a patient with congenitally corrected transposition of the great arteries [20]. Currently, MitraClip therapy for severe TR have been performed in 8 patients, of which 6 were done with the transjugular access and the other 2 cases transfemorally (Fig. 24.4). The numerous challenges of this approach include the three-leaflet configuration of the TV, the presence of huge annular dilatation and lack of coaptation, the different tissue properties of the tricuspid leaflets and also the use of reliable echo imaging to guide the procedure, which is actually not optimal for tricuspid interventional procedures.