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Response of Wallstents to dilation: therapeutic implications
Z J Haskal1, J M LaBerge, R L Gordon
1Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia 19104.
Purpose:
The authors document the degree of in vitro shortening of the Wallstent when expanded to different diameters and demonstrate the clinical importance of this property.
Materials And Methods:
Forty-two-, 68- and 94-mm size Wallstents were expanded within cylinders that were 6, 8, 10, and 12 mm in diameter, and their lengths were measured.
Results:
Progressive stent shortening occurred between diameters of 6 and 10 mm. Extreme shortening occurred at overdilation to 12 mm: At this diameter a 42-mm stent is 24.5 mm long (vs 46 mm at a 10-mm diameter), a 68-mm stent is 40 mm (vs 65 mm), and a 94-mm stent is 64 mm (vs 95 mm).
Conclusions:
Specific knowledge of stent lengths at different diameters is required for proper stent choice and accurate deployment. Over-dilation to a 12-mm diameter is useful in correcting excessive stenting and resistant stent narrowings, but it can result in excessive shortening requiring additional stent placement.