Drug-eluting stents are primarily used in patients with atherosclerosis, to open up narrowed and obstructed coronary arteries.
Some examples of clinical situations that require the use of a stents are described below:
Patients who have suffered a cardiac event such as a heart attack due to narrowed coronary arteries may be advised to undergo coronary angioplasty. The vascular narrowing is caused by the formation of an atherosclerotic plaque that decreases the size of the vascular lumen, the space inside the vessel that blood flows through.
A coronary angioplasty involves the use of an inflated balloon to stretch the blocked artery open and, today, the procedure usually includes the insertion of a stent. The stent is coated in an anti-proliferative or anti-inflammatory drug that is eluted to help prevent further blockage and narrowing of the vessel.
Several large clinical trials have demonstrated that coronary angioplasty using bare metal stents that are not coated in medication is a superior procedure to simple balloon angioplasty, where the arteries are simply opened up but not supported by an inserted scaffold.
However, several clinical trials have also shown that drug-eluting stents are superior to bare-metal stents in preventing coronary artery narrowing. The drug-eluting stents were associated with lower rates of adverse cardiac events such as heart attack and repeat intervention due to re-narrowing or restenosis of the artery.
Stents may be used in cases of atherosclerosis, before the patient has reached the stage of having a heart attack. The stent is used to dilate and keep open narrowed coronary arteries that would otherwise cause a reduced blood supply to regions of the heart and heart muscles. This condition is called ischemia and may lead to chest pain, angina or myocardial infarction.
Coronary Artery Bypass Procedure
Drug-eluting stents are also used on an off-label basis to reduce complications following a coronary artery bypass procedure. Here, the blockage in the coronary artery is bypassed using the saphenous vein from the leg. One end of the vein graft is sewn into the aorta and the other end is stitched to a part of the coronary artery that is beyond the obstructed point.
Sometimes, the graft from the leg vein also becomes narrow and blocked again at some point after surgery and drug-eluting stents have been used successfully to prevent this. However, “off-label” use means the stents have not yet been approved for use in this context by the Food and Drug Administration.
Reviewed by Sally Robertson, BSc