Fenestration of aortic stent grafts-in vitro tests using various device combinations

To evaluate the response of various stent grafts after needle fenestration and sequential dilation with standard percutaneous transluminal angioplasty (PTA) and cutting balloons and sealing of the fenestration with a side branch stent graft.

Five commercially available aortic stent grafts (Endurant, Gore TAG, Talent, Valiant, and Zenith) were fenestrated with a needle. The fenestrations were sequentially dilated up to 10 mm with PTA balloons or cutting balloons. The residual diameter stenosis and visual appearance of the fenestration was estimated after each dilation. The joint between the main prosthesis and a side branch stent graft, placed through the fenestration, was visually assessed.

Stent grafts responded variably after fenestration and balloon dilation; the holes were round or oval with smooth, fringed, frayed, or torn edges. Talent and Valiant fabrics were easiest to dilate, whereas Zenith was the most resilient. Dilation with a cutting balloon led to fully open fenestrations in all stent grafts. Good apposition of the side branch stent graft to the main prosthesis was achieved unless fenestration was located in close proximity to a stent strut.

The balloon-based technique, especially the cutting balloon, fully opened the fenestrations up to 10 mm, and the fenestrations could be successfully covered with side branch stent grafts. Various graft fabrics responded variably to balloon dilation, however, which may have significant impact on the clinical in situ fenestration of individual aortic stent grafts.