High flexibility, kink resistant catheter shaft

A method of accessing a tortuous vascular anatomy with a flexible, kink resistant endovascular catheter, the catheter comprising a proximal end section, a proximal mid-section, and a distal section including a distal tubular body defining a central lumen;

• the distal tubular body including an inner tubular layer surrounding the central lumen, an outer tubular layer, a helical support having adjacent loops spaced axially apart, disposed concentrically over the inner tubular layer and being within the outer tubular layer;
• wherein the inner tubular layer and the outer tubular layer are bonded together between the adjacent loops of the helical support and a distance between adjacent loops is greater at the distal section than the proximal mid-section;
• the distal section is more flexible than the proximal mid-section;
• the catheter is about 8 F in outer diameter, the method comprising:
• accessing the tortuous vascular anatomy by advancing the catheter with the distal tubular body to bend from a straight configuration to a bent configuration through the tortuous vascular anatomy;
• wherein the distal tubular body is bent, such that the distal tubular body provides controlled hinging to reduce a tendency for the distal tubular body to kink at a bending point, wherein the controlled hinging is in the form of corrugations in the distal tubular body on an inside bend of the distal tubular body;
• and
• wherein the distal tubular body does not kink when bent to form an arcuate portion having a radius measured from an inner curvature of no more than about 0.4 inches.

A method of accessing a tortuous vascular anatomy with a catheter, the catheter comprising a proximal end section comprising a polyether-block-amide material, a proximal mid-section comprising a polyether-block-amide material with a first stiffness, and a distal section comprising a material that has a second stiffness less than the first stiffness of the proximal mid-section to provide for a soft catheter tip with increased flexibility compared to the proximal mid-section;

• the distal section including a distal tubular body defining a central lumen;
• the distal tubular body including an inner tubular layer surrounding the central lumen, an outer tubular layer, a helical support having adjacent loops spaced axially apart, disposed concentrically over the inner tubular layer and being within the outer tubular layer, and extending through the proximal end section, the proximal mid-section, and the distal section;
• the inner tubular layer and the outer tubular layer are bonded together between the adjacent loops of the helical support, and a distance between the adjacent loops is greater at the distal section than at the proximal mid-section;
• and the distal section is more flexible than the proximal mid-section and provides sufficient flexibility and stiffness to traverse through a tortuous vascular anatomy;
• and the catheter is about 8 F in outer diameter, the method comprising:
• accessing the tortuous vascular anatomy by advancing the catheter through the tortuous vascular anatomy such that the distal section is more flexible than the proximal mid-section and the proximal mid-section is more flexible than the proximal end section;
• and
• navigating the catheter by causing the distal tubular body to bend from a straight configuration to a bent configuration;
• wherein the distal tubular body is bent, such that, when the distal tubular body is in the bent configuration, the distal tubular body includes corrugations on an inside bend of the distal tubular body to reduce a tendency for the distal tubular body to kink at a bending point, the corrugations form an organized corrugated surface along an inside curve of the distal tubular body when the catheter is in the bent configuration;
• wherein the helical support comprises nitinol and has a cross sectional dimension of no more than about 0.006 inches and, when the distal tubular body is in the bent configuration, a wavelength λ1 of an axial space between the adjacent loops on the inside bend is less than a wavelength λ2 of an axial space between the adjacent loops on an outside bend and the organized corrugated surface includes the corrugations on an outside surface of the distal tubular body and includes the corrugations which define part of the central lumen of the distal tubular body;
• wherein the distance between the adjacent loops of the helical support provides the corrugations at the inside bend of the distal tubular body when the distal tubular body is in the bent configuration and wherein the corrugations at the inside bend of the distal tubular body are disposed on both an inner surface defining the central lumen and the outside surface of the distal tubular body;
• and
• wherein the distal tubular body does not kink when bent to form an arcuate portion having a radius measured from an inner curvature of no more than 0.4 inches.