Page 18 - Journal of Structural Heart Disease Volume 3, Issue 6

Original Research Article
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fracture pattern [11]. In our experience, pre-stenting at the time of intentional stent fracture caused no further injury to the vessel wall, and injury scores im- proved at mid-term evaluation.
Macroscopic examination of stented vessels pro- vided no evidence of damage to the surrounding tissue or transmural vessel injury. This is important because in vitro testing of stents with intentional fracture produces an irregular fracture pattern, with many stent struts protruding tangentially [13]. These externally protruding stent fragments can penetrate through blood vessels and damage adjacent soft tis- sue, including arteriovenous malformations [11, 18, 19]. However, pre-stenting allows realignment of the struts of intentionally broken stents, which remain embedded in the vessel wall, in a more ideal circular fashion.
Our study has some limitations. The experiments were performed in a growing piglet model that has di erent growth velocity characteristics than hu- mans. Nevertheless, this model has been employed in similar studies to mimic the growth of infants and small children [6]. Although the number of stents and animals were small, they were adequate to achieve statistical signi cance in the areas demonstrated. We assessed only one type of stent in this in vivo study, which was selected based on its superior character- istics in our in vitro bench testing [4]. Pressure gra- dients across the stents were not measured in all animals because we found only very small (2–5 mm Hg) gradients across stented segments in the few we measured. Moreover, our model was not intended to
create signi cant coarctation with pressure gradients; rather, it was designed to evaluate the feasibility and characteristics of the pre-stenting technique.
In conclusion, our study shows that pre-stenting at the time of intentional pre-existing stent frac- ture provides advantages over simple stent fracture. Pre-stented vessels had larger vessel diameters, main- tained better vessel patency, had more complete en- dothelialization, and showed no protrusion of stent struts into vessel lumens. These ndings should be considered in small children requiring vessel angio- plasty or stenting.
Acknowledgements
We deeply appreciate and thank the Foroni Family of Madrid, Spain for their generous contributions sup- porting this work and related stent studies. We thank William Schoenlein, Melissa Bible, Tracy Moller, Gena Brock, and Richard Sieber for their contributions and assistance with animal experiments. We also thank Omar El-Sabrout for his input in the study and review of the manuscript.
Con ict of Interest
The authors have no con ict of interest relevant to this publication.
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Journal of Structural Heart Disease, December 2017
Volume 3, Issue 6:165-175