9:25 AM - 11:15 AM
[II-S02-01] Stent Unzipping Using Ultra High Pressure Balloon; In Vitro, and Animal Experiment
Background: As the child grows, the limitation of maximally dilatable stent diameter (MDD) may result in stenosis associated with size-mismatch. If an implanted stent can be intentionally fractured along its length called “unzipped”, it may eventually be redilated to the adult vessel diameter.
Few studies examined how smallest balloon diameter can unzip the stent using an ultra- high pressure balloon (UHB).
Methods: Several commercially available coronary (Liberte stent, LS) and peripheral vascular stents (Genesis renal and Express vascular SD stent, defined as GS and ES) were tested in vitro. Serial dilations were performed with 1 to 2 mm increments in balloon size until stent was fractured. We also investigated whether the balloon, which had unzipped the stent in vitro, would work similarly in the vessel of pig and the histological influence of the unzipped stent on the surrounding tissue.
Results: A total of 16 stents of diameters ranging from 4mm–6 mm (median 4mm) were tested. LS, GS and ES were unzipped predictably with the balloon of 1.5, 1.81 and 1.66 times of MDD, respectively. After unzipping, there was no histological damage on the surrounding tissue by unzipped strut.
Conclusion: Use of UHB enabled unzipping of the stent by balloon diameter smaller than 2 times of MDD. The ratio of smallest balloon diameter/MDD, which could unzip the stent varied by the type of stent. This technique may make it possible to put in a larger stent in the unzipped small stent by incremental steps.
Few studies examined how smallest balloon diameter can unzip the stent using an ultra- high pressure balloon (UHB).
Methods: Several commercially available coronary (Liberte stent, LS) and peripheral vascular stents (Genesis renal and Express vascular SD stent, defined as GS and ES) were tested in vitro. Serial dilations were performed with 1 to 2 mm increments in balloon size until stent was fractured. We also investigated whether the balloon, which had unzipped the stent in vitro, would work similarly in the vessel of pig and the histological influence of the unzipped stent on the surrounding tissue.
Results: A total of 16 stents of diameters ranging from 4mm–6 mm (median 4mm) were tested. LS, GS and ES were unzipped predictably with the balloon of 1.5, 1.81 and 1.66 times of MDD, respectively. After unzipping, there was no histological damage on the surrounding tissue by unzipped strut.
Conclusion: Use of UHB enabled unzipping of the stent by balloon diameter smaller than 2 times of MDD. The ratio of smallest balloon diameter/MDD, which could unzip the stent varied by the type of stent. This technique may make it possible to put in a larger stent in the unzipped small stent by incremental steps.