Ring Fracture of Brazilian Aortic Valve Bioprostheses Using Non-Compliant High-Pressure Transcatheter Balloon, an Ex Vivo Test.

Introduction: Aortic valve bioprostheses ring fracture in valve-in-valve procedures has shown low complication rates and presents as an option in the treatment of patients at high risk for conventional surgery, avoiding high transvalvular gradients, which are associated with increased mortality. Some prostheses available in the market cannot be fractured. In an ex vivo test, the possibility of ring fracture of aortic valve bioprostheses produced in Brazil when submitted to radial force application using a high-pressure non-compliant balloon was evaluated.

Methods: One unit of each aortic valve bioprosthesis model, sizes 19 and 21 mm, produced by Brazilian companies (Braile Biomédica, Cardioprótese, and Labcor), was used. In the experiment, a non-compliant high-pressure balloon (Atlas®-Gold), 1 mm larger than the external diameter of the prosthesis, was positioned inside the valve annulus and inflated gradually aiming to fracture the prosthesis. Fracture pressures and photographic and radiological images of the prostheses before and after test were recorded.

Results: All prostheses were fractured. In the models with metal ring, the fracture pressures were between 23 and 25 atm. In the other prostheses, the rupture occurred between 10 and 13 atm. No deformations in the structure were observed, which could potentially damage the aortic root.

Conclusion: All the Brazilian prostheses evaluated were fractured, although the presence of a metal ring in the prosthesis framework increases the pressure required for fracture. The information obtained helps in the planning of valve-in-valve procedures in patients with aortic valve bioprostheses.