Patent ID: 8172895

Claim:
A method of pre-operative sizing of a stent graft with at least two fenestrations for placement into a body vessel having an inner wall with side branch vessels and the stent graft intended for access to the side branch vessels through the fenestrations, the method comprising the steps of; a) determining the internal diameter of the body vessel at the level of the side branch vessels, b) assessing the angular position of the of each of the side branch vessels from a selected datum position on the vessel, c) converting the angular position to a circumferential distance along the inner wall of the vessel from the selected vessel datum to each side branch vessel for each of the branch vessels, d) selecting a diameter of stent graft which is 10% to 20% greater than the determined diameter of the vessel, e) defining a stent graft datum position on the stent graft, f) positioning fenestrations on the stent graft such that each is the converted distance calculated in step c) from the stent graft datum position on the stent graft; g) temporarily reducing the diameter of the stent graft at least at the level of the fenestrations at a position substantially diametrically opposite to the stent graft datum position and (h) the step of temporarily reducing the diameter comprising applying diameter reducing ties at a position diametrically opposed to the two fenestrations to give a diameter reduced portion and the diameter reduction not being applied in the region of the fenestrations; whereby the diameter reduced portion of the stent graft, when deployed, is as far around from the side branch vessels as possible.