Guide extension catheter

A medical treatment delivery system, the system comprising:

• a delivery device comprising a nose extending proximally from a distal end of the delivery device and a medical device location extending proximal from a proximal end of the nose, wherein the nose has a distal end with a length extending between the proximal end and the distal end of the nose;
• a guide extension catheter comprising:
• a proximal member having a proximal outer diameter, a proximal portion, and an extension portion extending from a distal end of the proximal portion to a distal end of the proximal member;
• and
• a distal sheath member axially fixed with respect to the proximal member and extending distally of the proximal member, the distal sheath member having a lumen and a distal outer diameter larger than the proximal outer diameter;
• and
• wherein the nose:
• has a distal taper that extends a greater distance than a length of the extension portion from the distal end of the proximal portion to the distal end of the proximal member;
• and
• is configured to track a guide wire extending through the lumen of the distal sheath member and align the medical device location of the delivery device with the lumen of the distal sheath member prior to the medical device location of the delivery device advancing to the extension portion of the proximal member.