Effect of Clover versus Zipping on Annular Geometry and Dynamics in Tricuspid Edge-to-Edge Repair

Introduction: Transcatheter edge-to-edge repair effectively reduces tricuspid regurgitation (TR), with some patients showing an additional 'annuloplasty effect'. Methods: Ten adult sheep underwent pulmonary artery banding to induce right ventricular failure and functional TR. Six weeks later, sonomicrometry crystals were implanted around the tricuspid annulus (TA). Two Abbott XTW clips were then placed using either a Zipping (n=5) or Clover (n=5) configuration. Echocardiographic and sonomicrometry data were collected before and after clip implantation to assess TA geometry and function. Results: The model produced right ventricular dilation, dysfunction, and moderate-to-severe functional TR. In all animals, leaflet approximation with two clips significantly reduced TR severity (3.6+/-0.5 to 1.3+/-1.1; p=0.01) and septal-lateral annular diameter (29.2+/-2.2 to 26.7+/-2.9 mm; p=0.01). However, a significant reduction in septal-lateral annular diameter occurred only with the Clover technique (30+/-2 to 27+/-1 mm; p=0.001). Conclusions: Both techniques reduced TR, but only the Clover configuration produced an acute annuloplasty effect by selectively decreasing septal-lateral annular diameter.