Apparatus for securing a device in a vascular lumen

A method comprising:

• partially deploying a first part of an anchor from a catheter in a vascular lumen, wherein the first part is a loop and is configured to expand as it is deployed;
• identifying, based on a two dimensional image of the expanded first part in the lumen, at least one of:
• (i) a roll angle of the anchor about a longitudinal axis of the lumen;
• and
• (ii) a longitudinal position of the anchor along the lumen;
• at least partially undeploying the first part of the anchor to collapse it back into the catheter;
• adjusting the roll angle based on said identifying to select the position of a second part of the anchor such that a device supported by the second part of the anchor is positioned against an interior wall of the lumen when the anchor is deployed;
• and
• deploying the anchor into the lumen for positioning a device in the lumen;
• wherein identifying comprises:
• allowing three radio opaque orientation markers carried on the first part to spread out during partial deployment of the loop from the catheter;
• and
• rotating the loop to determine its rotational alignment in the lumen;
• wherein the rotational alignment of the loop is determined by monitoring, using a radiography technique, for an increase or decrease in the spacing between a first centrally-located marker of the three markers and at least one or both of the two further markers provided on opposing sides of the loop as it is rotated.