Stent, microcatheter, braiding apparatus for continuous hoselike body, and process for manufacturing stent

A stent provided with superelasticity and having a plurality of thin wires which are composed of shape memory material, of which, alternately, one-half are wound in a shape of helices in one direction around a cylinder, and the other half are wound in a shape of helices in the other direction, with the thin wires in the one direction and the thin wires in the other direction obliquely intersecting like a plain weave, and which are braided into a hoselike body in a longitudinal direction with formation of reticulated gaps in the shape of diamonds, and which is provided with superelasticity, the stent comprising:

• thin wire coarsely braided hose portions in which the reticulated gaps having large opening areas are formed with coarse braiding along the longitudinal direction of the hoselike body, and
• a thin wire densely braided hose portion in which the reticulated gaps having smaller opening areas are formed with denser braiding than those of the thin wire coarsely braided hose portions with change in size of the reticulated gaps along a longitudinal direction of the hoselike body, while being constant in size thereof along a circumferential direction of the hoselike body such that the size of the reticulated gap of the thin wire coarsely braided hose portions along the circumferential direction of the hoselike body is equal to the size of the reticulated gap of the thin wire densely braided hose portions along the circumferential direction of the hoselike body, by changing intervals in a braiding direction of the plurality of thin wires being same in number as those of the thin wire densely braided hose portion, wherein
• the narrower of intervals of two intersecting axes in the diamond-shaped reticulated gaps of the thin wire densely braided hose portion is not larger than 0.1 mm.

A stent provided with superelasticity and having a plurality of thin wires which are composed of shape memory material, of which, alternately, one-half are wound in a shape of helices in one direction around a cylinder, and the other half are wound in a shape of helices in the other direction, with the thin wires in the one direction and the thin wires in the other direction obliquely intersecting like a plain weave, and which are braided into a hoselike body in a longitudinal direction with formation of reticulated gaps in the shape of diamonds and which is provided with superelasticity, the stent comprising:

• thin wire coarsely braided hose portions in which the reticulated gaps having large opening areas are formed with coarse braiding along the longitudinal direction of the hoselike body, and
• a thin wire densely braided hose portion in which the reticulated gaps having smaller opening areas are formed with denser braiding than those of the thin wire coarsely braided hose portion with change in size of the reticulated gaps along a longitudinal direction of the hoselike body, while being constant in size thereof along a circumferential direction of the hoselike body such that the size of the reticulated gap of the thin wire coarsely braided hose portions along the circumferential direction of the hoselike body is equal to the size of the reticulated gap of the thin wire densely braided hose portions along the circumferential direction of the hoselike body, by changing intervals in a braiding direction of the plurality of thin wires being same in number as those of the thin wire densely braided hose portion, wherein:
• the thin wire densely braided hose portion is placed in an intermediate position excluding end portions of an overall length L of the hoselike body in the longitudinal direction, has a length along the longitudinal direction of the hoselike body in a range from one-quarter to one-tenth of the length L, and has the reticulated gaps with the narrower of intervals of two intersecting axes in the diamond-shaped reticulated gaps of not larger than 0.1 mm, and wherein
• the thin wire coarsely braided hose portions are placed on both sides of the thin wire densely braided hose portion along the longitudinal direction of the hoselike body and have the reticulated gaps with the narrower of intervals of two intersecting axes in the diamond-shaped reticulated gaps being wider than a diameter of a catheter used for treatment of blood vessel dilation.