Paclitaxel-Eluting Stents: Are They All Equal? An Analysis of Six Randomized Controlled Trials in De Novo Lesions of 3,319 Patients

Abstract

In Germany, four different drug eluting stents (DES) systems are currently commercially available. Whereas sirolimus has been clinically tested in only a single type of stent with a single type of coating in only a single dose, paclitaxel has been tested on various stent designs, in various dose densities, and in various relase formulations with or without a polymer carrier. Therefore, the question arises: are all paclitaxel stents equally safe and effective? Six clinical randomized trials investigated the safety and efficacy of paclitaxel-eluting stents in patients with de-novo lesions: TAXUS-I (61 pats), TAXUS-II (536 pats), ASPECT (177 pats), ELUTES (190 pats), DELIVER-I (1041 pats) and TAXUS-IV (1314 pats). In the TAXUS-series, paclitaxel released from the stent was controlled by the Translute™ polymer. In the other studies, however, no polymer carrier was used. In TAXUS-I, II & IV, the dose density of 1 μg/mm2 significantly reduced angiographic parameters of restenosis and improved clinical outcomes. In ASPECT and ELUTES there was a dose-dependent effect on angiographic parameters of restenosis with the best results for a paclitaxel dose density of apprimately 3.0 μg/mm2. Clinical outcomes at 6 and 12 months, however, were not improved in these studies without coating. The studies unanimously show that the paclitaxel-eluting stents are safe, if clopidogrel is added to ASA for 3 to 6 months. The safety of paclitaxel-eluting stents is independent of the stent design, the dose density and the presence or absence of a polymer carrier system. For paclitaxel-eluting stents using a polymer carrier, the dose density of 1 μg/mm2 is highly effective, whereas for paclitaxel-eluting stents without a polymer carrier, the minimal effective dose density is much higher (3 μg/mm2). Despite their improvement of angiographic parameters, paclitaxel-eluting stents without a polymer carrier did not demonstrate a positive effect on clinical outcome. In contrast, polymer-based paclitaxel elution produced significant clinical benefit.