For many years, cardiovascular diseases have been the number one cause of death in Germany. To re-open the morbid narrowed coronary vessels for a sufficient blood circulation, an interventional treatment is possible. In this case the vessel gets expanded and is additionally supported by an endoluminal vascular implant, a so called stent. Coronary stents are commercially available in many different types and are already successfully used, but in the case of a stenosis in a bifurcated coronary region, the otherwise uncomplicated and safe treatment still causes some problems.
The commercially available stents for coronary bifurcations are usually laser cut two stent systems. In this case a first stent is placed and expanded in the main vessel and in a second step manually cracked in the position of the side vessel. Through the generated hole a second stent can be placed and inflated. With this procedure the critical region is the cross section, in which the two stents are not securely connected, to guarantee a plaque shift free and fully covered and supported transition area. Additional the flexibility of laser cut systems is limited.
The aim of the here introduced invention is to generate a product which is on one hand as flexible and compressible as possible and on the other hand ensures a proper dilation and support of the main and side vessel. To realize extreme compressibility and flexibility, a newly invented variation braiding technology has been chosen. With this technique it is able to write a program to produce a customized bifurcated y-shaped braid in one single fully automated braiding step.
As a material the shape memory alloy nickel/titanium has been selected, which, in combination with the used braiding technology, is able to generate the striven flexibility and at the same time enables the stent to radially expand independently when placed in the correct position in the vessel.
To create the “door” to the side vessel, one of the manufactured arms is shortened, and similar to a bud, pulled into the other arm. Following, the stent is compressed and implanted into the constricted area in the vessel. There the stent expands and opens the main vessel. Finally the pulled-in side arm gets released to open and support the crossover to the side vessel. To support the side vessel a second simple tube stent gets implanted through the “opened and secured door.”
Compared to the commonly used stent systems, the invention is more flexible and has a higher level of compressibility. As soon as the compressed stent has been placed in the right position, the door opener can be released so it deploys into the side vessel independently and dilates the critical crossover without plaque shift. If necessary a second stent can be placed in the side vessel. The crossover is securely coved and injuries and restenosis can be avoided. To avoid injuries all wire ends need to be secured. First prototypes have been produced.