Balloon catheter and method for manufacturing balloon

A method for manufacturing a balloon catheter balloon, the method comprising:

• molding a material into a balloon possessing a predetermined shape and extending in an axial direction;
• protruding a part of the balloon outward in a radial direction such that inner surfaces of the part of the balloon face one another;
• and
• welding at least part of the inner surfaces of the part of the balloon to each other to form a projection portion, the projection portion extending for a predetermined length in the axial direction of the balloon.

A balloon catheter comprising:

• a flexible elongated shaft which possesses a distal portion;
• a balloon fixed to the distal portion of the elongated shaft, the balloon configured to expand outward in a radial direction and contract inward in the radial direction, the balloon possessing an outer surface;
• the balloon comprising an effective expansion portion which is cylindrically shaped when the balloon is expanded;
• the balloon comprising at least one projection portion protruding radially outward, the at least one projection portion extending radially outward beyond the effective expansion portion when the balloon is expanded;
• the at least one projection portion comprising inner surfaces that face one another, the inner surfaces of the projection portion that face one another being at least partially welded together;
• and
• the entire balloon being integrally formed in one piece at the same time such that the effective expansion portion and the at least one projection portion of the balloon are a unitary structure.