How Controlled is the Expansion of VIATORR CX?

PurposeTo investigate and compare the physical properties of the new generation Gore VIATORR-Controlled Expansion Endoprosthesis (VCX) to those of the predecessor VIATORR stent in an in vitro experimental setup.Materials and MethodsA total of 12 stents (8 VCX; 4 VIATORR; GORE, USA) were examined. Radial resistive force (RRF) and chronic outward force (COF) were assessed using a radial force testing machine (RX-650, Machine Solutions Inc., USA). To assess the radial forces of the VCX above 8 mm, balloon expansion was performed between cycles.ResultsAll VCX stents show an abrupt decrease in COF at an external diameter of 8.3 mm; RRF decreases likewise at an external diameter of 8.5 mm. The predecessor VIATORR stent without the controlled expansion feature shows linear radial force reduction until full expansion at a diameter of 10 mm.The physical properties of the VCX can be altered by balloon modulation. Point of COF (RRF) reduction shifts to 8.5 mm (8.6 mm), 8.6 mm (8.8 mm) and 9.3 mm (9.6 mm) following modulation with a 8 mm, 9 mm and 10 mm balloon.ConclusionsThe VCX shows an abrupt and disproportionate decrease in COF and RRF at an external diameter of 8.3 mm, thus passive expansion to its nominal diameter of 10 mm is not to be expected. By means of balloon dilatation the physical properties of the stent can be altered, enabling customized TIPS creation. The previous VIATORR stent shows continuous COF and RRF until total expansion.

Automated summary

The study investigated and compared the physical properties of the new generation VCX stent with the predecessor VIATORR stent. Results showed that the VCX stent had an abrupt decrease in COF and RRF at an external diameter of 8.3 mm and 8.5 mm respectively, while the VIATORR stent only fully expanded at a diameter of 10 mm. Balloon dilatation could alter the physical properties of the VCX stent, allowing customized TIPS creation, while the VIATORR stent maintained continuous COF and RRF until total expansion.