A Design Feasibility Investigation for a Pulmonary ePTFE Transcatheter Pediatric Heart Valve

The most replaced valve in the congenital heart defects population is the pulmonary valve. Current treatments require multiple invasive, open-heart surgeries to replace the pulmonary valve as the patient grows. Minimally-invasive procedures, such as transcatheter pulmonary valve replacement, circumvent open heart surgery, which benefits patients and physicians. ePTFE valves have gained prominence recently because they allow cardiothoracic pediatric surgeons to tailor the valve size to the patient. Clinical studies point to the high patency of ePTFE valves. Currently, there are no FDA-approved transcatheter valves made with ePTFE. The purpose of this paper is to offer a preliminary design feasibility investigation of developing a transcatheter ePTFE pulmonary valve. We used an existing FDA-approved Medtronic Ensemble II delivery system to test and evaluate the feasibility of fitting an ePTFE pediatric valve to this existing deployment system. The prototyping and testing goals were: (1) to evaluate stent expansion, (2) to explore anchoring mechanisms, (3) to collapse the stent with the ePTFE conduit down to a size that would fit into a catheter, and (4) to expand and deploy the ePTFE stent-conduit pulmonary valve. Testing revealed that ePTFE conduits with wall thicknesses of 1 mm and 0.5 mm did not collapse to a small enough diameter to fit in the sheath of the Medtronic Ensemble II delivery system. However, expansion of anchored stents showed that valves upheld circular cross-sections when deployed. For the valve to be widely distributed, the product must follow FDA and ISO 5840 standards to ensure appropriate performance. There remains considerable future work to deliver a well-functioning ePTFE transcatheter pulmonary heart valve solution for pediatric patients.