Medical device and method for treatment

A method for treatment to remove by suction an obstruction that has occurred in a lesion part in a lumen of a living body, the method comprising:

• providing a medical device comprising an elongated shaft part, an expandable part, a covering part, and a sheath configured to house the expandable part and the covering part in a contracted state, the expandable part being an elastically deformable cylindrical body with a plurality of pores, the cylindrical body having a first end and a second end, and a proximal part connected to the elongated shaft part;
• and the covering part being flexible and deformable independent of the expandable part, the covering part having a cover proximal part connected to the proximal part of the expandable part or connected to the elongated shaft part located at a proximal side with respect to the expandable part, and the expandable part having a maximum outer diameter larger than a maximum inner diameter of the covering part, when the expandable part is not covered by the covering part and when the expandable part is in a natural state in the absence of external forces, and wherein in the expanded state, the covering part has a uniform outer diameter over a predefined range in an axial direction at a distal side end part, and the expandable part includes a portion which decreases in outer diameter toward the distal side over an extent surrounded by the covering part, whereby a gap is formed between the distal side end part of the expandable part and the expandable part;
• pushing the expandable part and the covering part out from the sheath to a downstream side beyond the lesion part in the lumen of the living body;
• allowing the expandable part to expand by its own elastic force, and causing the covering part to come into contact with the lumen of the living body, while securing a space between the end part of the distal side of the covering part and the expandable part;
• crushing or dissolving an obstruction that has occurred in the lesion part in the lumen of the living body;
• inserting a device provided with suction into the lumen of the living body, thereby suctioning the crushed or dissolved obstruction;
• and
• housing the expandable part and covering part in the sheath in a contracted state;
• and
• pulling the medical device out of the lumen of the living body.

A medical device comprising:

• an expandable part configured for elastic deformation, the expandable part having an expanded state when in a natural state in the absence of external forces;
• a covering part including a flexible and deformable tubular member surrounding an outer periphery of the expandable part;
• and
• a shaft part extending through the expandable part and the covering part;
• wherein the covering part is only fastened to the expandable part at a cover proximal part such that the covering part is configured for deformation independently from the expandable part;
• wherein the expandable part has a maximum outer diameter larger than a maximum inner diameter of the covering part, when the expandable part is not covered by the covering part and when the expandable part is in a natural state in the absence of external forces;
• and
• wherein, in the expanded state, the covering part has a uniform outer diameter over a predefined range in an axial direction at a distal side end part, and the expandable part includes a portion which decreases in outer diameter toward the distal side over an extent surrounded by the covering part, whereby a gap is formed between the distal side end part of the expandable part and the expandable part.

A medical device configured to be inserted into a lumen of a living body so as to block a flow in the lumen of the living body, the medical device comprising:

• an elongated shaft part;
• an expandable part;
• and
• a covering part,
• the expandable part being an elastically deformable cylindrical body with a plurality of pores, the cylindrical body having a first end and a second end, and a proximal part connected to the elongated shaft part, and
• the covering part being flexible and deformable independent of the expandable part, the covering part having a cover proximal part connected to the proximal part of the expandable part or connected to the elongated shaft part located at a proximal side with respect to the expandable part,
• wherein the expandable part is configured to obtain an expanded shape in which a central part of the cylindrical body has a larger outer diameter than an outer diameter of both the first end and the second end of the cylindrical body, when the expandable part is in a natural state in the absence of external forces,
• wherein the covering part is configured to have a cylindrical shape surrounding an outer periphery of the expandable part such that a space is defined in a radial direction between a distal side end part of the cylindrical shape and the expandable part, and
• wherein the expandable part has a maximum outer diameter larger than a maximum inner diameter of the covering part, when the expandable part is not covered by the covering part and when the expandable part is in a natural state in the absence of external forces.