Đang chuẩn bị liên kết để tải về tài liệu:
Endovascular Aneurysm Repair - part 3

Hình. 6. Việc mở rộng của bóng bay, stent trần Đó là Bao và bóng bay gắn kết và mở rộng bởi các IS Thể hiện tại áp lực lạm phát khác nhau. Việc mở rộng của ống đỡ động mạch trần và Bao IS tương tự như mỗi khác Trong phạm vi áp lực của lò nướng đến sáu quán bar | Latex covering of Palmaz stents and its effect on stent expansion I 23 Fig. 6. The expansion of balloons bare and covered stents that are mounted and expanded by the balloons is shown at different inflation pressures. The expansion of bare and covered stents is similar to each other within the pressure range of four to six bars Fig. 7. Stent recoil is minimal for both bare and covered stents The bare and covered stents showed a 7 to 9 stent recoil that means they slightly collapsed following removal of the balloons Fig. 7 . Recoil was observed following stent expansion by both a six and a ten millimeter balloon. Divergence from the ideal cylindrical form was observed in both types of stents following removal of the balloon Fig. 8 . The configuration of an ideal cylinder corresponds to 0 on the chart. The bare stents showed a minimal constriction of 3 in their central part indicated by a negative value. Contrarily the covered stents had a slight bulge of 3.5 in the central part with a corresponding positive value. 24 I Experimental studies Fig. 8. Divergence from the cylindrical stent configuration was observed following removal of the balloons. Bare stents showed a slight central constriction and contrarily covered stents a central bulge Discussion The present experiment demonstrates that latex covering of stents is feasible and does not substantially alter the characteristics of the stents. We chose the Palmaz stent because of its rigidity probably resisting to the elastic recoil of a covering and the preservation of length during expansion. The final stent diameter is predictable because stent expansion is defined by the diameter of the balloon. For these reasons measurements are easy to perform. We selected latex for the production of covered stents because of its high elasticity and imperviousness. Yet the tissue reaction towards latex was inflammatory and extensive jeopardizing probably the biocompatibility of latex covered stents and making them unsuitable .