Catheter

A method comprising:

• inserting a catheter into a radial artery of a living body, the catheter comprising:
• an inner layer forming an inner surface of a tubular catheter main body having a lumen, an outer layer forming an outer surface of the catheter main body, the catheter main body possessing an inner diameter, an outer diameter, a distal end, and a wall thickness, multiple reinforcements between the inner surface and the outer surface of the catheter main body, and the catheter satisfying Expressions (1), (2), and (3) below:
• 0.050 mm≤T1≤0.100 mm Expression (1)
• T2/T1≥0.25 Expression (2)
• 60,000≤(D1×D2×W×N)/(T12×T2)<1,000,000 Expression (3),
• wherein the inner diameter of the catheter main body is D1, the outer diameter of the catheter main body is D2, the wall thickness of the catheter main body is T1, a thickness of each reinforcement along a radial direction of the catheter main body is T2, an effective width of each reinforcement along the circumferential direction of the catheter main body in a cross section orthogonal to an axial direction of the catheter main body is W, and a total number of the multiple reinforcements is N;
• advancing the catheter from the radial artery toward a blood vessel in a lower extremity of the living body;
• positioning the distal end of the catheter at a target site in the blood vessel in the lower extremity of the living body;
• and
• determining a kink exists along the catheter while the distal end of the catheter is in the blood vessel in the lower extremity of the living body;
• and
• introducing a guide wire into the catheter when a kink is determined to exist along the catheter and advancing the guide wire through the kink.