Major stent deformation/pseudofracture of 7 Crown Endeavor/Micro Driver stent platform: incidence and causative factors

Aims: This is the initial report of stent deformation / pseudofracture of the 7 crown Endeavor / Micro Driver stent platform (2.25-2.75 mm), whereby the post-dilation balloon catches and causes major stent deformation angiographically appearing as a large stent fracture. We sought to determine frequency and cause. Methods and results: Analysis of 1,000 consecutive Endeavor/Micro Driver stents (7 crown) deployed at our institution. Bench testing was also performed by deploying 10 stents in 2.5 mm tubing and then attempting re-crossing with non-compliant balloons. Clinical results: There were 14 cases of major stent deformation/pseudofracture representing an incidence of 1.4% or 1.8% of 775 stents that were post-dilated. Of the 14 deformed stents, re-stenting was required in nine and MACE occurred in five (36%.). Benchtop results: Balloon "catch" was reproducible at an initial frequency of 9% and affected three of the 10 stents. With the use of provocative measures stent deformation occurred in 50% of test stents. Conclusions: Stent deformation/pseudofracture of the 7 crown Endeavor/Micro Driver platform occurred in 1.8% of cases that were post-dilated. Of these, 36% experience MACE. Deformation can be reproduced on the benchtop. Operators should be aware of the complication, and develop strategies to deal with it.