New Expandable Polyurethane Stent valve, Implanted by Catheter, in Pediatric and Adults Patients. Analysis of Perfomance Testes

OBJECTIVE: Manufacture of an Expandable Polyurethane Stent Valve®, may reduce the repeated operations of valve replacement, during the growth phase of the patient, with heart valve disease
METHODS: 1- In vitro testing: I- Physical testing. Prostheses were submitted to universal testing to generate force versus deformation (stretching), for each test. II- Hydrodynamic testing. Were performed in duplicate pulses. Prostheses with diameters from 12 to 22 mm, were submitted to pulsatile physiological flow and stress conditions. All testing was certified by a Professional Engineer, using design required by ISO 5840-3-2015. 2- In vivo testing: III- Experimental implants in sheep. Ten sheep was submitted to prosthesis implant, by hybrid trans catheter technique in pulmonary position. In Group A: Four sheep w/ 20 kg, expanded up to 22mm. There was 2 dead, at early follow-up. Three sheep of Group A, were undergo balloon expansion, up to 22 mm, in the 12th month of follow-up. Three sheep were submitted to prosthesis explant, with six, nine and ten months of follow-up.
RESULTS: Physical and Hydrodynamic testing of Polyurethane sample removal of stent valve, before and after undergoing to 30 minutes crimping, showed preservation of properties of resistance and elasticity elongation. In vitro durability was proven for >15 years. The histologic, radiologic and electron microscopic examination of these four prosthesis shows: integrity of structure and free of calcification. Seven survival sheep was submitted to programmed prosthesis explant, from 6th and 24th months of follow-up. No prosthesis presented structural alterations or calcification.
CONCLUSIONS: Expandable polyurethane stent valve, with special design for implant and expansion in growing children, has experimental satisfactory hemodynamic performance and durability in vitro and in vivo tests. Calcification and structural changes were not observed. In the next step, clinical studies are be planned, in 2019.

Team: Miguel Maluf, Mariana Gurgel, Andre Gimenes, Fernando Zanoni, Ovandir Bazan, Jayme Ortiz