A new endovascular size reducer for large pulmonary outflow tract.

Around 75% of patients with severe pulmonary insufficiency requiring valvular replacement are excluded from percutaneous pulmonary valve implantation (PPVI) due to a large ventricular outflow tract. To extend the indication of PPVI to these patients, a new size reducer has been designed. This 35-mm size reducer was successfully deployed inside the main pulmonary artery through a 21-Fr delivery catheter in six sheep. A 20-mm pericardial valved stent was subsequently deployed inside the size reducer to restore pulmonary valve continence. We successfully verified the efficiency of the delivery catheter by controlling the deployment precisely and reversibly. In all six cases, device positioning was satisfactory. There was no post-procedural residual stenosis in the right ventricular outflow tract in haemodynamic (9.5+/-3 mm Hg), echocardiographic and angiographic studies. After 8-12 weeks of follow-up, no prosthetic migration occurred. The transprosthetic systolic gradient remained low (4+/-2.5 mm Hg) during follow-up. There was one trivial persistent paraprosthetic leak. This study confirmed the feasibility and the effectiveness of this new size reducer to reduce the size of the pulmonary artery.