When someone experiences an acute myocardial infarction, it is literally vital for doctors to open up the blocked artery. A coronary stent does just that. Implanted in a procedure called percutaneous coronary intervention, a coronary stent is a metal tube, typically coated with anti-hyperplasia medication that is released over time, implanted in the coronary artery to ensure that blood flow is not blocked. A stent is a long-term device, interned to shore up the arterial wall and keep it from collapsing for years. Stents are also implanted preventatively in arteries that have not become blocked if doctors feel there is a significant danger of blockage.
Another name for the percutaneous coronary intervention procedure is angioplasty. In an angioplasty, the artery is first unblocked and enlarged using a small balloon, which is inserted through a small incision in the arm or leg and then inflated near the location where the artery is blocked. Once the blockage is cleared, a stent is placed to hold the artery open. The procedure needs to be performed quickly, because the balloon itself blocks blood flow, and needs to be removed as soon as feasible. Angioplasty usually does not require general anesthesia.
The stent is a foreign object and its placement involves injury to the body, which means that the surgery itself triggers clotting and the stent elicits an immune response. That is why modern stents are coated with medication. Unfortunately, the medication in the coating can, in some patients, actually encourage the clotting it is supposed to prevent. Medical researchers have proposed using vitamin C, which is as effective as the medications currently used at stopping growth, because vitamin C also helps avoid the problem of clotting.
In addition to the drugs on the stent itself, angioplasty patients are typically prescribed anti-coagulants—blood thinners—after the procedure. However, almost a third of patients never fill these prescriptions, creating a dangerous situation. Patients who delay taking medication have the highest risk of death in the month following surgery. In one study, delaying medication meant patients were five times as likely to die within 30 days of the procedure, as well as three times as likely to have a heart attack.