Results from the LESSON I trial presented today provide preliminary evidence for the therapeutic benefit of the newer generation everolimus-eluting stent over the previous gold standard, the early generation sirolimus-eluting stent. Moreover, LESSON I provides evidence that the formation of blood clots (stent thrombosis) - the principal shortcoming of early generation drug-eluting stents - may be diminished with the newer generation everolimus-eluting stent.
"The latter observation," said principal investigator Professor Stephan Windecker from Bern University Hospital, Switzerland, "may have important implications for ongoing studies on prolonged duration of dual antiplatelet therapy after DES implantation, but will require confirmation in randomised clinical trials."
Drug-eluting stents (DES) are designed to scaffold narrowed coronary arteries resulting from coronary artery disease. By means of the radial strength of the cylindrical mesh, DES keep the artery open, maintain blood flow, and gradually release an anti-proliferative drug into the surrounding tissue. The role of the drug is to prevent re-narrowing of the artery within the stented segment by scar tissue.
The first generation of DES effectively prevented re-narrowing of the artery but were associated with a small risk of stent thrombosis late after stent implantation. Newer generation DES have been developed using modified polymers and thinner metal struts, whose aim is to further improve upon the results of early generation DES.
The LESSON I (Long-term comparison of Everolimus-eluting and Sirolimus-eluting Stents for cOronary revascularizatioN) study compared 1601 patients undergoing treatment with everolimus-eluting stents with 1532 patients having treatment with sirolimus-eluting stents in a propensity-score matched analysis. The study involved all patients having percutaneous coronary intervention (PCI) with either everolimus-eluting or sirolimus-eluting stents at Bern University Hospital between 2004 and 2009.