Drug-Eluting Stents: device without polymers overcomes limitations of first generations stents

The NEXT randomized trial showed the superiority of a polymer-free amphilimus-eluting stent compared to paclitaxel-eluting stents with permanent polymers

The NEXT clinical trial (International Randomized Comparison Between DES Limus Carbostent and Taxus Drug-Eluting Stents in the Treatment of De Novo Coronary Lesions), is a multicenter randomized trial (n=296) comparing coronary amphilimus eluting stent Cre8 (CID, Saluggia, Italy), versus permanent-polymer paclitaxel-eluting stents (Taxus Liberté, Boston Scientific, Natick, Massachusetts). This new stent has a carbon coating (i-Carbonfilm) with small reservoirs holding an antiproliferative amphilimus (a formulation of Sirolimus). Previous Cre8 stent insertion in experimental animals has proved optimal re-endothelialization, low rates of neointimal proliferation and a significative absence of inflammatory processes. The NEXT trial showed superiority of the new device compared to the permanent polymer eluting stents, for the study’s primary outcome (6 month follow up angiographic in-stent loss). A sub analysis in 48 patients undergoing intravascular ultrasound (27 Cre8, Taxus 21) confirmed its superiority. After a 12 month follow up, the re-intervention rate of lesions treated with the new device was 4,7%, compared to a 6,1% of the control [group] (p=NS). Only 2 definitive in-stent thrombosis cases were confirmed, one in each group. No significant differences were observed in major cardiac events rates (cardiac death, infarction, and re-intervention).

Commentary

First generation DES (permanent polymers eluting stents) have shown significant benefits in terms of need for re-intervention, especially for patients with high risk of restenosis. Yet, they presented no minor rates of late thrombotic events1. These events have been detected in the context of a chronic local inflammatory process and an incomplete reendothelization2,3, often associated to the presence of permanent polymers. Design improvement of new-generation stents has been impressive, introducing changes in platform, polymers and drugs. New prototypes of DES with neutral or bioabsorbable polymers, or without polymers at all, result in less local inflammatory processes and a reduced rate of late thrombosis. Cre8 is a third generation stent that sustains drug elution a long time, completing drug release after 90 days from implant. Its prolonged elution translates into a powerful antiproliferative effect. At the same time, absence of inflammation (due to its passive carbon coating and the polymer-free formulation) is a predictor of low risk of late thrombosis. Studies with a larger number of patients and a more extensive follow up will reveal its role in the big family of available DES in the percutaneous intervention of coronary lesions.

1.McFadden EP, Stabile E, Regar E, et al. Late thrombosis in drug-eluting coronary stents after discontinuation of antiplatelet therapy. Lancet 2004;364:1519-21.

2.Finn AV, Joner M, Nakazawa G, et al. Pathological correlates of late drug-eluting stent thrombosis: strut coverage as a marker of endothelialization. Circulation 2007;115:2435-41.

3.Finn AV, Nakazawa G, Joner M, et al. Vascular responses to drug eluting stents: importance of delayed healing. Arterioscler Thromb Vasc Biol 2007;27:1500-10.

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