STENT registry: Real-world US stent data

Sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES) have each shown promising results in reducing late target lesion and target vessel revascularization (TVR) rates when compared to bare metal stents in a variety of clinical and angiographic subsets of patients with coronary artery disease. This includes many set- tings not evaluated in the original pivotal trials that led to Food and Drug Administration approval. For example, both small vessels (< 2.75 mm) and long lesions (> 18 mm) have been included in the C-SIRIUS' and E-SIRIUS(2) trials. Other important patient subsets are entered into prospective registries and compared retrospectively, including those with acute coronary syndromes, ST-elevation myocardial infarction (MI), chronic total occlusions (CTOs), saphenous vein graft (SVG) lesions, and instent restenosis (ISR). While PES and SES are being implanted widely in very similar settings, these stents differ in metallic geometry and polymer coatings as well as in terms of the drug being eluted. Both stents elute compounds that inhibit the cell cycle, but at different stages: The Cypher stents elute sirolimus, which induces G, cell cycle inhibition, while TAXUS stents release paclitaxel, which predominantly leads to M-phase arrest. Thus, the properties of these compounds have distinct effects on critical molecular and cellular events associated with the pathophysiology of restenosis.(3) Such differences in geometry, coatings, and pleiotropic anti-restenotic effects may be responsible for the varying results observed in recent head-to-head trials and registries comparing different stent systems. These include the REALITY,(4) ISAR-DESIRE,(5) SIRTAX,(6) and TAXi(7) trials and the LONG-DES,(8) COLUMBO, and RESEARCH/T-SEARCH(9) registries. According to Charles A. Simonton, MID, FACC, there are a number of problems with the available head-to-head trials of drug-eluting stents (DES): small sample size, powered for angiographic but not clinical endpoints, single- or dual-center experiences, and clinical heterogeneity (e.g., patients with diabetes, ISR, or small vessels). Clearly, the data from such comparisons may not be generalizable. A meta-analysis of single-center trials favored SES, but the studies were conducted without an independent core lab (Slide 1).(10) However, the reduction in restenosis with SES was not associated with a similar reduction in mortality or MI rate. The authors acknowledged that the low event rate and limited length of follow-up would limit the ability to detect potential differences in the incidences of death or MI. Thus, despite what appears to be an abundance of data, comparative safety and clinical efficacy outcomes are needed for the complex patients, procedures, and lesions being treated with these devices in "real-world" clinical practice.