US Patent 11173279 Microcatheter

A microcatheter is characterized as having a hardness-transition section along an entire or partial length an outer layer, hardness of the outer layer varying in the hardness-transition section so as to increase from the distal tip to the proximal tip along the lengthwise direction, due to arrangement of a second forming material in a stripe pattern extending in the lengthwise direction of the outer layer in the first forming material including a forming material formable into the outer layer so that a surface area ratio of the two forming materials in a circumferential direction of a cross section varies along the lengthwise direction for the first forming material and the second forming material.