Preclinical evaluation of a transcatheter aortic valve replacement system for patients with rheumatic heart disease

Abstract

Aims: Cardiac surgery in middle-income countries differs significantly from that in high-income countries regarding prevailing heart valve pathologies and access to cardiac surgery. Typically, rheumatic aortic regurgitation in the absence of calcification by far outweighs stenosis. As such, entirely different transcatheter aortic valve implantation (TAVI) concepts are required for these regions. The aim of the study was to evaluate the five-month performance of the SAT (Strait Access Technologies, Cape Town, South Africa) pericardial TAVI system in the orthotopic aortic position of juvenile sheep.Methods and results: A self-homing, non-occlusive balloon-expandable TAVI system comprising a hollow balloon, stabilising locator trunks, a scalloped CoCr stent with elevating anchorage arms and decellularised, sandwich-crosslinked pericardium was compared with control surgical valves (Edwards PERIMOUNT) in sheep. The implantation period was five months. The tactile placement of the TAVI valves was accomplished without the need for rapid pacing. At termination, no structural degeneration was observed in either group. The TAVIs were well healed with the stent struts largely embedded in tissue. Correlating with sheep growth (weight gain of 40.4±13.0%) during the implantation period, mean transvalvular gradients increased from 3.08±1.95 mmHg to 8.50±5.38 mmHg (p=0.044) after five months.Conclusions: A single-stage, balloon-expandable, easy to place TAVI system with antigen-depleted and antigen-masked bioprosthetic leaflets promises to address the distinct needs of low-and middle-income countries with regard to TAVI better than conventional systems.

Progressive Reinvention or Destination Lost? Half a Century of Cardiovascular Tissue Engineering

“…As trans-catheter valves are being crimped to small diameters for implantation they depend on crimpable soft-leaflets. Presently, these leaflets are made of bioprosthetic tissue but polymers or other foldable materials that can withstand the mechanical forces during the cardiac cycle are on the horizon (61). As contemporary bioprosthetic leaflets degenerate fast in younger patients (49), TAVIs are currently restricted to patients older than 70 years of age.…”

The use of semi‐compliant versus non‐compliant balloon systems for predilatation during the implantation of self‐expandable transcatheter aortic valves

“…Its cylindrical hollow shape ensures a continuous blood flow during the balloon expansion and entirely eliminates the need for rapid pacing. 31 This might lead to improved perioperative hemodynamic stability and a better outcome after TAVR.…”

The “Cairo Accord”- Towards the Eradication of RHD: An Update

“…Parallel progress in the design of affordable percutaneous tools for insertion of these valves is being made (109)(110)(111).…”