Tissue treatment devices, systems, and methods

A device for performing a medical procedure in the intestine of a patient comprising:

• a guidewire;
• an elongate shaft assembly comprising:
• a shaft assembly first section comprising a distal section of the shaft assembly;
• a shaft assembly second section proximal to the shaft assembly first section;
• a shaft assembly third section proximal to the shaft assembly second section;
• and
• a shaft assembly fourth section comprising a distal tip;
• a functional assembly positioned on the shaft assembly first section, the functional assembly comprising an expandable element configured to expand to a diameter of at least 18 mm;
• and
• a guidewire lumen configured to slidingly receive the guidewire,
• wherein the shaft assembly first section terminates at a distal end of the functional assembly,
• wherein the distal tip comprises a tapered portion of the shaft assembly extending beyond the distal end of the functional assembly,
• wherein the distal tip comprises a proximal tip segment and a distal tip segment,
• wherein the distal tip segment comprises a smaller diameter than the proximal tip segment,
• wherein a taper and/or a wall thickness variation of the distal tip configures the proximal tip segment to have a stiffness greater than a stiffness of the guidewire and the distal tip segment to have a stiffness less than the stiffness of the guidewire, and
• wherein a proximal end of the distal tip has a stiffness approximately equal to a stiffness of a distal end of the shaft assembly first section.