A tie layer insert is disclosed to aid in bond formation between an expandable balloon and a distal portion of a catheter shaft. The tie layer insert can be a single layer applied directly to the structural surfaces, or alternatively, the tie layer may be incorporated into a preformed polymeric insert. In the latter embodiment, the polymeric insert may include several layers of polymeric material. During the manufacturing process, the preformed polymeric insert is positioned between the distal portion of the expandable balloon and the catheter shaft. The entire distal region is then processed to form a sealably bonded expandable balloon to the distal end of the catheter shaft.
