3 The technologies
3.1 The stent–graft typically comprises a self-expanding nickel–titanium (nitinol) stent attached to a woven polyester fabric graft. Bifurcated grafts are modular with multiple segments: a proximal tube, a flow divider, a full-length ipsilateral iliac limb and a short contralateral stump for attachment of the second iliac limb. The stent–grafts are attached to the aortic wall by metallic wires, hooks and anchors. Additional modular components include aortic and iliac extender cuffs, which are used for the treatment of type I endoleaks. The main types of endovascular stent–grafts are: aortic tube grafts (no longer used in the UK), aorto-uni-iliac grafts and aorto-bi-iliac (bifurcated) grafts (the latter are most commonly used in the UK).
3.2 Five stent–grafts have been included in this appraisal. These are the Talent stent–graft (Medtronic), Excluder AAA endoprosthesis (WL Gore), Aorfix AAA stent–graft (Lombard Medical), Zenith AAA endovascular graft (Cook Medical) and Endologix Powerlink Systems (Le Maitre). All have been granted Conformité Européene (CE) marking for use within European Union (EU) countries. The indications for use for each of the stent–grafts vary; these are given in the instructions for each device.
3.3 The individual endovascular stent–grafts made by different companies each have a different cost. Costs are further complicated by the fact that patients who are fitted with the same manufacturer's device may require different numbers of components. The manufacturers who produce the devices also offer different pricing structures; for example, some charge a price per patient regardless of the number of components needed, whereas others base their price on the number of parts required.
3.4 Four of the manufacturers stated that their list prices were commercial-in-confidence. Lombard Medical stated that the price of their Aorfix AAA stent–graft was £5000, which was a fixed price per patient irrespective of the number of components used. A price to the NHS of £5000 was supported by limited sample data for 2007/08 collected by the NHS Purchasing and Supply Agency from some NHS organisations in England. These data confirmed that the average price of an endovascular stent–graft, irrespective of the number of components used, was £5000.