Transcatheter implantation of self-expandable valved prosthesis in outlet right ventricle an experimental study in pigs.

INTRODUCTION: Patients with congenital heart disease who underwent pulmonary valvotomy or surgery to open the pulmonary valve ring are prone to develop residual pulmonary insufficiency or stenosis that may lead to right heart failure with clinical deterioration. These children require multiple interventions throughout their lives, which impose a high rate of morbidity and mortality. OBJECTIVE: To develop a less invasive technique for implantation of a valved prosthesis through the right ventricle. METHODS: The valved prosthesis consists of an auto expanding metal stent built with nitinol, surrounded with polyester, where the three leaflets of bovine pericardium were mounted. Twelve pigs were used to perform the implants. Echocardiographic control was performed immediately after implantation and one, four, eight and 12 weeks. RESULTS: One animal showed reflux of moderate to severe and three mild reflux. Transvalvular gradients measured before implantation ranged from 3 to 6 mmHg and that soon after the implant was increased, ranging from 7 to 45 mmHg. There was a decrease in these gradients during follow up and in only four of the twelve animals the gradients were above 20 mmHg. Thrombus formation occurred in the prosthesis of six animals, and this was the most frequent complication. CONCLUSION: These findings highlight the need for studies with the use of anticoagulants and antiplatelet, an attempt to reduce this event. The study aims to contribute for the start of the use of prosthetic heart valves that could be implanted through minimally invasive techniques without the use of cardiopulmonary bypass.