Method and apparatus for using an expandable element to ascertain vessel diameter

An apparatus for determining an effective diameter of a vessel, the apparatus comprising:

• an expandable element having a proximal region and a distal region, the expandable element moveable between a collapsed configuration in which the expandable element has a collapsed length and a collapsed diameter and an expanded configuration in which the expandable element has a decreased length and an increased diameter;
• an outer elongate member having a distal region secured relative to the proximal region of the expandable element, the outer elongate member defining a lumen extending therewithin;
• and
• an inner elongate member having a distal region secured relative to the distal region of the expandable element, the inner elongate member extending through the lumen;
• wherein proximal movement of the inner elongate member relative to the outer elongate member causes the expandable element to decrease in length and thus increase in diameter until the braid urges the vessel into a more uniform cross-sectional shape;
• and
• wherein the expandable element is adapted to be visible under an imaging technique such that one or more dimensions of the expandable element are measurable.

An apparatus for determining an effective diameter of a vessel at a deployment site, the vessel including vessel walls, the apparatus comprising:

• a braid having a proximal region and a distal region, the braid moveable between a collapsed configuration and an expanded configuration, the braid adapted to be visible under fluoroscopy;
• an outer sheath overlying the braid, the outer sheath constraining the braid in its collapsed configuration while the outer sheath overlies the braid;
• wherein the outer sheath is adapted to be withdrawn proximally to expose the braid, thereby allowing the braid to expand towards its expanded configuration until braid apposes the vessel walls, the braid expansion limited by interaction with the vessel walls;
• and
• wherein fluoroscopy may be used to ascertain one or more dimensions of the braid.