Late complication of stent fragmentation related to the "lever-arm effect".

PURPOSE: To report an unusual case of dramatic nitinol stent strut fractures with resultant complete loss of stent integrity in a cadaveric lower limb graft. CASE REPORT: A 73-year-old man had the clinical stigmata of graft versus host response to a cadaveric femoral-tibioperoneal graft and suspected inflammation-induced stent corrosion culminating in fracture. The long continuous stented segment and station of the distal anastomosis below the knee resulted in preferential displacement of force to the proximal stent edge as the knee bends, making mechanical stress the most likely primary cause for these findings.
CONCLUSION: This case provides insight into some of the unique mechanical issues in vessels traversing the knee joint and how the problem is amplified by increasing the distance between the knee (fulcrum) and the stented vessel (lever arm). This lever-arm effect would also apply to the native superficial femoral artery when vessel compliance is changed by multiple stents.