Not until 1990 did the FDA approve the Palmaz stent for use in the iliac arteries. The Palmaz stent with its tubular design with staggered rectangular slots allows for expansion during deployment by balloon expansion. It is crimped onto the balloon before introduction through the protective sheath. Longitudinal flexibility refers to the ability to pass through vascular bends or tortuous vessels. The reported advantages of the self-expandable stents are high expansion ratio, smaller introducer profile, and high longitudinal flexibility.
Intimal hyperplasia is the result of a healing or adaptation process that has grown out of control.
Under normal conditions, vascular healing should be self-limiting and not lead to a significant obstruction of the lumen, as long as adequate flow is maintained. Intimal hyperplasia occurs when the injury is excessive, when too much necrotic debris is represent, when the wound edges are not properly adapted, or when irritating local stimuli persist, as is the case with stents. The Gianturco stent consists of a wire bent into a zigzag pattern with ends connected to form a cylinder. To date, the perfect stent does not exist. This tubular, flexible, woven wire braided into self-expanding configurations is probably the easiest and most widely used stent in the world.