Apparatus and methods for sealing a vascular puncture

An apparatus for sealing a puncture extending through tissue, comprising:

• an outer member comprising proximal and distal ends defining a longitudinal axis therebetween, and a lumen extending between the proximal and distal ends;
• an expandable member comprising proximal and distal ends, the proximal end of the expandable member being coupled to the distal end of the outer member such that an interior of the expandable member communicates with the lumen, the expandable member being expandable from a collapsed state to an expanded state when fluid is introduced into the interior;
• an inner member slidably coupled to the outer member and comprising proximal and distal ends, the distal end being coupled to the distal end of the expandable member, the inner member being biased to move distally relative to the outer member for moving the distal end of the expandable member away from the proximal end of the expandable member to at least partially collapse the expandable member;
• and
• an element coupled to the inner member and comprising a surface exposed to the lumen such that, when fluid is introduced into the lumen, fluid pressure from the fluid pushes against the surface, causing the inner member to move proximally relative to the outer member for moving the distal end of the expandable member towards the proximal end of the expandable member a cylinder extending from the proximal end of the outer member, the element coupled to the inner member comprising a piston slidable within the cylinder and coupled to the proximal end of the inner member.