Coronary Stent - Re-occlusion

Re-occlusion

Coronary artery stents, typically a metal framework, can be placed inside the artery to help keep it open. However, as the stent is a foreign object (not native to the body), it incites an immune response. This may cause scar tissue (cell proliferation) to rapidly grow over the stent. In addition, there is a strong tendency for clots to form at the site where the stent damages the arterial wall. Since platelets are involved in the clotting process, patients must take dual antiplatelet therapy afterwards, usually clopidogrel and aspirin for one year and aspirin indefinitely. In order to reduce the treatment, new generation of stent has been developed with biodegradable polymer.

However, the dual antiplatelet therapy may be insufficient to fully prevent clots that may result in stent thrombosis; these and the cell proliferation may cause the standard (“bare-metal”) stents to become blocked (restenosis). Drug-eluting stents were designed to lessen this problem; by releasing an antiproliferative drug (drugs typically used against cancer or as immunosuppressants), they can help avoid this in-stent restenosis (re-narrowing).