The study, which is being presented at the European Society of Cardiology (ESC) 2012 Annual Congress, examined the effects in the patient of two drug-eluting stents with different healing characteristics (the Endeavor™ zotarolimus-eluting stent, E-ZES, and the Cypher™ sirolimus-eluting stent, C-SES). These scaffold-like medical devices are placed into narrowed arteries to prevent the artery from becoming blocked, and, unlike earlier devices (so-called bare metal stents) which provided purely structural support, are able to slowly release a drug that reduces the cell proliferation, which may otherwise lead to an exuberant scar formation at the site of the stent and narrowing or even occlusion of the vessel.
While drug-eluting stents have been used successfully in millions of patients, evidence suggests that the body sometimes reacts to the stent with local inflammation that increases the risks of delayed healing and the formation of blood clots, a process known as stent thrombosis, which can lead to dangerous adverse events such as myocardial infarction (heart attack).
A team of scientists led by Dr Edoardo Camenzind of the University of Geneva in Switzerland compared the long-term safety of two different types of drug-eluting stent, with different potencies and healing characteristics, the response to the E-ZES being similar to the vascular healing response after bare metal stent implantation. They examined a group of nearly 9000 patients over three years, to determine whether there was any difference in the likelihood of clot formation between the two different types of stent.
According to Dr Camenzind, "Over three years, there seems to be no significant difference in the observed levels of definite or probable stent thrombosis between the two types of stent we tested. However, when we performed a time analysis, this suggested that a difference is emerging over time. Our results seem to suggest that differences are most prominent when use of dual antiplatelet therapy is low, which leads us to postulate that it may prove important for clinicians to ensure that patients who receive stent implants strongly inhibiting cell proliferation also receive an appropriate duration of dual antiplatelet therapy."*
In a linked Comment published alongside the research, Prof. Dr. Jörg Hausleiter and colleagues of the Deutsches Herzzentrum in Munich, add that "Since the study began in 2007, there has been a significant shift in interventional cardiology practice such that both study devices have largely fallen out of use worldwide, being superseded by newer devices with higher efficacy and lower rates of stent thrombosis. Nevertheless, the data remains of interest to physicians caring for the millions of patients already treated with these stents. In addition, the authors have dispelled the misconception that the in-stent tissue growth (thickening of the arteries) associated with less effective drug eluting stents confers lower risk for stent thrombosis."
NOTES TO EDITORS
* Quotes direct from authors and cannot be found in text of Article / Comment.
Dr Edoardo Camenzind, University of Geneva, Switzerland
T) +41 79 207 9879 E) email@example.com
Prof. Dr. Jörg Hausleiter, Deutsches Herzzentrum München, Klinik an der Technischen Universität, Munich, Germany
T) +49 89 1218 4018 E) firstname.lastname@example.org