If narrowed or blocked coronary vessels have to be widened or opened, a vascular support (stent) is usually inserted. Drug-coated stents are preferred for patients at high risk of renewed narrowing of vessels (restenosis). However, the use of antibody-coated stents has been increasing in recent years. Current studies provide indications that these new antibody-coated stents more frequently lead to myocardial infarction and make re-operation necessary. This is the conclusion reached in the rapid report of the German Institute for Quality and Efficiency in Health Care (IQWiG), as published on 12 October 2012.
Focus on patients with a high risk of restenosis
The Federal Joint Committee (G-BA) had commissioned IQWiG to investigate the advantages and disadvantages of antibody-coated stents in comparison to alternative measures, focussing on patients with coronary heart disease (CHD) at high risk of restenosis. This depends on factors including the duration and degree of the narrowing as well as its precise localization. The curvature of the affected vessels can also play a role.
Even stented vessels may become blocked again
Narrowed coronary vessels are generally expanded by surgery and stabilized with stents (tubes of wire mesh). But even vessels supported by stents can become blocked again, if there is excessive tissue growth. Re-operation is then necessary (revascularization). Moreover, stents are foreign bodies. If they are not fully covered with a smooth cell layer (epithelium), platelets are more likely to stick to them and blood clots (thromboses) are more likely to form on them. It is attempted to counteract these two main risks (thrombosis formation and tissue proliferation) by specifically coating the stent and by treating the patient with anticoagulants.
Risk of thrombosis increases
The first generation of stents consisted of pure metal (bare-metal stents, BMS) and are now rar
|Contact: Anna-Sabine Ernst|
Institute for Quality and Efficiency in Health Care