Guidance on the use of coronary artery stents

Ongoing trials for paclitaxel-eluting stents include TAXUS I (follow-up of a small initial study of slow-release formulation versus BMS in patients with either previously untreated lesions or restenosis), TAXUS II (follow-up of a larger study of both slow- and moderate-release formulations versus BMS in patients with previously untreated lesions), TAXUS IV (a large trial of slow-release formulation versus BMS stratified by presence or absence of diabetes and by vessel diameter), TAXUS V (focussing on small vessels, long lesions, bifurcations and in-stent restenosis) and TAXUS VI (moderate release for long lesions). For sirolimus-eluting stents, ongoing trials include RAVEL (small-diameter vessels), SIRIUS (high risk for cardiovascular disease progression and restenosis due to the diabetes, exposure to multiple stent implantation and use of overlapping stents) and E-SIRIUS (previously untreated single vessels of diameter 2.5 to 3 mm and for lesions between 15 and 32 mm in length); and FUTURE (previously untreated vessels between 2.75 and 4 mm, less than 28 mm long) for everolimus-eluting stents. REALITY, a head-to-head trial of the Cypher sirolimus DES and Taxus paclitaxel DES, is under way.

Until now, trials have been restricted to single-artery studies for the sake of simplicity and ease of interpretation. Extrapolation of results to more than 1 artery critically depends on untested assumptions. Randomised controlled trials (RCTs) of the use of DES in more than 1 artery concurrently are therefore required, in order to confirm or refute the appropriateness of the extrapolations used in the modelling.

To compare long-term outcomes, particularly with respect to stents against CABG, much longer trial follow-ups are required.

New BMS designs should be tested against current BMS and DES designs.

Head-to-head RCTs of those DES that have been CE marked and have been shown to be clinically superior to the corresponding BMS are required.

Studies to determine whether diabetes is a risk factor for increased rate of restenosis following PCI, independent of lesion length and artery calibre, are required. Much of this work could be performed by an analysis of patient-level data taken from trials already conducted.