The microcatheter comprises a
catheter body, the
catheter body is of a multi-layer
composite structure, and the
catheter body sequentially comprises an outer layer, a middle layer and an inner layer from outside to inside; a first conical section and a second conical section are arranged on the two sides of the outer layer respectively, and the first conical section and the second conical section are symmetrical about the central axis of the catheter; an inclined plane is formed at the joint of the first conical section and the outer layer part as well as the joint of the second conical section and the outer layer part, and the included
angle alpha between the inclined plane and the axis of the outer layer is 5-30 degrees; the maximum outer
diameter of the first conical section and the maximum outer
diameter of the second conical section are larger than the outer
diameter of the catheter body. The outer diameter of the expandable cavity in the unexpanded state is the same as that of the catheter body, the maximum outer diameter of the expandable cavity in the expanded state is 1.5-3 times of the outer diameter of the catheter body, and the expandable cavity is located on the first conical section. Gradient distribution of mechanical properties is achieved through a multi-layer
composite structure, the middle layer and the inner layer provide balance of support and flexibility, the outer layer forms a fluid resistance structure through the conical sections which are symmetrically arranged, geometric parameters of the conical sections of the outer layer are cooperatively controlled, a structural anti-
reflux barrier is established on the premise that the overall
trafficability of the guide
pipe is kept, and the service life of the guide
pipe is prolonged. Meanwhile, the
size change design of the conical section can adapt to
dissection environments with different
blood vessel diameters.