Hungarian Radiology

[The force transmission of the distal endings of stent delivery systems]

SZIKRA Péter, VÖRÖS Erika, SZTRIHA László, SZÓLICS Alex, CSIKÁSZ Tamás

OCTOBER 10, 2005

Hungarian Radiology - 2005;79(05)

[INTRODUCTION - In cases of endovascular treatment of internal carotid artery stenosis, one of the most important aspects is to minimise embolic complications. Dislodging emboli may be influenced by the shape and size of tapered endings of stent delivery systems. Our team performed measurements and calculations on the emergence of force of the various tapered endings. MATERIAL AND METHOD - Five different commercially available stent dilivery systems were investigated. The thickness of the devices were measured and taking 5 mm normal artery diameter, the lumen size was calculated, above which the delivery system should dilate the lumen mechanically. By means of geometrical computer-constructions and measurements, we analysed the forces directed ahead and laterally, emerging on the surface of tapered endings during the passing through the stenosis. RESULTS - The stent delivery systems were between 5.0 and 5.9 F in diameter, and even the stent delivery system of lowest profile would dilate a stenosis of over 89%. The different endings are tapered with variable lengths. The force transmission on the vessel wall of different directions was distinct at the various points of the cone surfaces. The forces directed ahead were less than those directed laterally on the larger part of a cone surface. Irregularity of the cone surfaces distributed the forces unfavorably. Considering the features of tapered endings, the atraumatic introduction of the devices required a range of upper limits of stenoses between 89.76-98.04%, which are more feasible values than those deternined by shaft sizes. CONCLUSIONS - Our experimental work suggests, that the shape and size of the endings of stent delivery systems influence the forces affecting vessel wall plaques, and in this manner, embolic complications, during carotid stenting. The lowest risk of embolisation could be induced by using the longest and smoothest tapered endings.]

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