Balloon catheters and methods of manufacture and use

A balloon catheter, comprising:

• an outer elongate shaft having a wall thickness that is less than 0.0035 inches;
• an inner elongate shaft with a delivery lumen therein, the inner elongate shaft within the outer elongate shaft having a section that extends distally beyond the outer elongate shaft, the inner elongate shaft having a wall thickness that is less than 0.0035 inches;
• an adapter secured to a distal region of the outer elongate shaft, the adapter having a stepped down distal region extending distally beyond the outer elongate shaft, the distal region of the adapter having an outer surface disposed radially inward relative to an outer surface of a distal end of the outer elongate shaft, the adapter having a proximal region having an inner surface disposed radially outward relative to the outer surface of the distal end of the outer elongate shaft, wherein the adapter has a length from 2 mm to 25 mm;
• an inflatable balloon with a proximal end;
• a proximal collar radially outside of the proximal end of the inflatable balloon, the proximal collar compressing the proximal end of the inflatable balloon between the proximal collar and the outer surface of the distal region of the adapter, wherein an inner surface of the proximal end of the inflatable balloon is disposed radially inward relative to the outer surface of the distal end of the outer elongate shaft,
• wherein the outer elongate shaft does not include a step-down in a region proximal to the proximal end of the inflatable balloon to the distal end of the outer elongate shaft;
• the inflatable balloon having a distal end stabilized relative to the section of the inner elongate shaft that extends distally beyond the outer elongate shaft, the distal end of the inflatable balloon having the inner surface that is disposed radially inward relative to the outer surface of the distal end of the outer elongate shaft,
• the outer elongate shaft and the inner elongate shaft forming an inflation lumen that is in communication with the inflatable balloon to allow fluid to be advanced through the inflation lumen and into an internal volume of the inflatable balloon to inflate the inflatable balloon,
• wherein the inflatable balloon along an entirety of its length is disposed substantially at or below an outer diameter of the outer elongate shaft when in an unexpanded configuration.