Abstract: A microcatheter includes an inner polymeric tube defining an inner lumen. It includes a proximal section with an inner wire layer helically wound in a constricted state over the inner polymeric tube and includes an outer wire layer helically wound over the inner wire layer in a constricted state within the proximal section. It includes a distal section with a distal wire layer helically wound in a constricted state and having an outer diameter. The proximal and distal sections are joined. The outer diameter of the outer wire layer is substantially the same as the outer diameter of distal wire layer at the location where the proximal and distal sections are joined.

Abstract: A microcatheter includes an inner polymeric tube defining an inner lumen. It includes a proximal section with an inner wire layer helically wound in a constricted state over the inner polymeric tube and includes an outer wire layer helically wound over the inner wire layer in a constricted state within the proximal section. It includes a distal section with a distal wire layer helically wound in a constricted state and having an outer diameter. The proximal and distal sections are joined. The outer diameter of the outer wire layer is substantially the same as the outer diameter of distal wire layer at the location where the proximal and distal sections are joined.