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What can we learn from explanted endovascular devices?
1Department of General, Vascular and Thoracic Surgery, General Hospital of Hamburg-Harburg, Eissendorfer Pferdeweg 52, D-21149 Hamburg, Germany.
Objective:
To examine the durability of the Stentor and Vanguard endovascular devices in human implants.
Methods:
The textile covering, the polypropylene ligatures and the stent metal of 34 devices (25 Stentor, 9 Vanguard) with a mean duration of implantation of 28.8 +/- 16 months was examined by means of stereomicroscopy and scanning electron microscopy.
Results:
The polyester textile covering showed gaps along the sutured seam and isolated holes in the fabric. All of the examined polypropylene ligatures were worn, some ruptured. Four different types of stent corrosion were classified--pits (100%), bizarre craters (68%), large deficiencies (14%) and fractures (32%).
Conclusion:
Holes in the polyester fabric and frame dislocations are specific for the design of Stentor and Vanguard grafts. The early corrosion of the stent metal Nitinol in these devices is surprising. Until more experience is gained with other devices, we have to be reminded, that the "gold standard" for the long-term durability of artificial vascular grafts is still "today's" conventional graft.