Off-Pump Replacement of the Pulmonary Valve in Large Right Ventricular Outflow Tracts: A Transcatheter Approach Using an Intravascular Infundibulum Reducer

Abstract

We report our experience of pulmonary valve replacement in animals with large right ventricular outflow tracts (RVOTs) using a percutaneous approach. We intended to implant a device to percutaneously reduce the diameter of the pulmonary artery (PA). Following its insertion, we intended to implant a valved stent inside the restriction. Animals were killed acutely (group 1, n=6) and after a mean follow-up of 1 (group 2, n=3) and 2 mo (group 3, n=9). In group 1, all reducers were successfully deployed and allowed the reduction of the PA to a diameter of 12-mm. In one animal, the proximal part of the reducer did not reach its final configuration. Another reducer embolized when manipulating the stiff wire. The insertion of valves was therefore possible in 17/18 animals. One animal died from an arrhythmia during positioning of the valve. Angiographic evaluations showed no leak between devices and the pulmonary wall. During the follow-up, there was no device migration. At autopsy, reducers were fixed to the pulmonary wall and completely covered by a fibrous tissue. In conclusion, with the use of an intravascular reducer, implantation of a pulmonary valve is possible in sheep through a transcatheter approach when the RVOT exceeds 22-mm in diameter.