Tricuspid valved stent implantation: novel stent with a self-expandable super-absorbent polymer.

OBJECTIVE Trans-catheter aortic and pulmonary valve replacement procedures can result in favorable outcomes in selected patients. The aim of this study was to investigate the functioning of a novel self-expanding valved stent with super-absorbent polymer (SAP) for minimally invasive replacement of the tricuspid valve. METHODS A newly designed nitinol stent with SAP was specially designed for the tricuspid annulus. This device was composed of right atrial anchoring elements, a left ventricular tubular stent, and a trileaflet bovine pericardial valve. The stent was coated with a waterproof material, and a pouch containing SAP for minimizing paravalvular leakage was placed beneath the atrial element. Seven pigs underwent minimally invasive off-pump tricuspid valved stent implantation. This was performed through a lower ministernotomy using a transventricular approach under transesophageal echocardiographic guidance. After 1 and 6h, a complete echocardiographic evaluation and hemodynamics (Swan-Ganz catheter) were performed. RESULTS Six of seven pigs exhibited normal hemodynamics immediately after tricuspid valved stent implantation and maintained stability for the entire period of monitoring. In one pig, a part of the atrial stent elements was deployed into the right ventricle, leading to significant paravalvular leakage, and died very soon. All subsequent animals survived with good results in the observation period. Accurate positioning of the valved stent was documented in six of seven pigs. SAP expanded and filled the gap between the stent and the native annulus in all animals. Mild paravalvular leakage was found in two of the six animals. Nevertheless, the observed leakage decreased to trace levels 6h after implantation. In the additional four pigs, only trace tricuspid regurgitation was revealed. No right ventricular outflow tract obstruction was detected. CONCLUSIONS Trans-apical off-pump tricuspid valved stent implantation is feasible in an acute experimental setting, and SAP may help to reduce paravalvular leakages.