Feasibility Study of a Novel Transcatheter Tricuspid Annuloplasty System in a Porcine Model

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SUMMARY
Gradually, more attention has been paid to tricuspid regurgitation. Formerly the "forgotten valvular heart disease," it has been recognized as having high incidence and adverse prognosis if untreated. However, isolated tricuspid valve surgery carries substantial risk and is thus not recommended. The K-Clip transcatheter tricuspid annuloplasty system has recently emerged as a minimally invasive therapeutic option that may help address these unmet clinical needs. The K-Clip technology simulates the Kay's procedure, which reduces the dimensions of the tricuspid annulus by folding and clamping the tricuspid annulus issue with a rigid clamping device. The feasibility of the K-Clip technology was investigated in this study, and annulus area reduction and declining tricuspid regurgitation grades were noted following the procedure. The findings of this study suggest that the K-Clip system may potentially be applicable as a novel transcatheter tricuspid annuloplasty device for the G radually more attention has been paid to tricuspid regurgitation. Formerly the "forgotten valvular heart disease," it has been recognized as having high incidence and adverse prognosis if untreated. 1,2 Moreover, the majority of all tricuspid regurgitations are secondary or functional, which are mainly related to significant tricuspid annular dilatation. 1 Surgical ring annuloplasty is the preferred treatment of secondary tricuspid regurgitation, 3  well as detaching, is promoted by mechanical transmission, and the control system is loaded on the delivery system. The delivery system is composed of 2   thrombosis. In addition, the heart, liver, spleen, lung, kidney, and brain of the animal were removed for gross observation, and pathological sections were used to observe thromboembolism and tissue change.   Table 1).  EXPLANTATION RESULTS. In total, 6 pigs were explanted immediately after the procedure, 6 pigs were explanted at the 28th day after the procedure, and the other 6 pigs lived to the endpoint and were then sacrificed.
In the acute test, the gross observation showed that the clip device was securely attached to the tricuspid annulus tissue with annulus tissue in between the clip arms ( Figure 5A). In the subacute test and endpoint explantation, gross observation showed that the clip device had been completely endothelialized ( Figures 5B and 5C). There was no cardiac perforation and no impairment of the tricuspid valve complex. None of the 12 pigs developed infective endocarditis. The heart, liver, spleen, kidneys, and brain were unremarkable in terms of thrombosis, thromboembolism, and infarcts in all animals.

DISCUSSION
The K-Clip system is a novel transcatheter tricuspid annuloplasty system, and this short-term follow-up animal study demonstrated that it was feasible and safe to use this system to perform a catheter-  leaflet, shortening the distance between anterior leaflet and posterior-septal leaflets, and resulting in a functionally bicuspid valve. 11 The Trialign system (Mitralign, Inc) is another transcatheter annuloplasty system that mimics the Kay surgical procedure, which has finished a small amount of clinical application. 8,12 According to the early feasibility study of the Trialign system, a 6.5% reduction of tricuspid annulus area has proven to be effective in tricuspid regurgitation correction. 12 An 11.7% reduction of tricuspid annulus area has been evaluated in this study; therefore, the principle of the K-Clip may potentially be applicable in the treatment of severe tricuspid regurgitation in humans. Both systems are delivered via percutaneous jugular vein access, and the route is short and straight for the convenience of manipulation. However, compared with Trialign, the K-Clip has its theoretical advantages.
First, the K-clip procedure may be technically easier than that of Trialign. The Trialign system needs to fasten 2 pledgets on the annulus, which need to manipulate the delivery catheter advance across the tricuspid valve, and penetrates the leaflet tissue using a wire from right ventricle to right atrium; afterwards, the wire needs to be snared from the jugular vein using the second sheath and externalized. Catheter navigation in the enlarged right heart chambers can be challenging, and this process needs to be repeated at least twice. [12][13][14] The K-Clip system, however, is Second, the K-clip procedure may have a higher safety coefficient than that of Trialign. In the K-clip procedure, anchoring on the annulus using the corkscrew rather than puncturing the leaflet tissue can effectively avoid procedure-related risks, such as pledget detachment, leaflet impairment, coronary artery rupture, cardiac perforation, and the like. 12,14 Also, anchoring with the corkscrew is very reliable, and no device detachment has been noted in this study. Moreover, the depth of the corkscrew is limited to 4 mm to reduce the risk of cardiac perforation.
Finally, the K-clip procedure may have higher flexibility than that of Trialign. In the K-clip procedure, if the site of the anchor on the annulus is not satisfactory, the corkscrew can be withdrawn easily; afterward, the position of the corkscrew can be readjusted. However, in the Trialign procedure, after the wire passes through the leaflet tissue, changing the position of the pledget cannot be that easy.
The first-in-man studies of K-Clip system are now underway in China.
STUDY LIMITATIONS. First, the study follow-up was only 90 days, and no long-term follow-up results   The K-Clip Transcatheter Tricuspid Annuloplasty System J U N E 2 0 2 2 : 6 0 0 -6 0 7