If you’ve been diagnosed with an ST-elevation heart attack, or STEMI, experts recommend that you receive clot-busting drugs within 30 minutes of arrival at the hospital, or, even better, that you undergo angioplasty with stent (a tiny mesh tube inserted during angioplasty to hold the artery open) within 90 minutes. In people diagnosed with non-STEMI or angina, the situation is not quite so urgent in the short term, and you may be monitored for a longer period before your doctors recommend a particular treatment.
There are four primary reasons for doing angioplasty and stent placement:
1) When medicines and lifestyle changes are not providing sufficient relief from angina symptoms;
2) When tests show that you are at high risk for having a heart attack because you have severe disease of the coronary arteries;
3) If you have a sudden worsening of angina that signals an impending heart attack (a condition called acute coronary syndrome);
4) If you are having a heart attack. The choice of angioplasty and stent placement versus bypass surgery depends on the location and severity of your artery blockages and your general health. For example, people with diabetes may get better relief of their angina from bypass surgery than from angioplasty.
Most of the time, angioplasty and stent placement is successful in opening a blocked artery and relieving symptoms. Sometimes, though, the blockage can grow back, even through the holes in the stent. This new blockage is called restenosis. It happens up to 20% of the time, usually between 3 and 12 months after the angioplasty and stent placement. Restenosis occurs less often with drug-eluting stents than with bare-metal stents.
A blood clot sometimes forms inside a stent. This is called stent thrombosis. It can occur immediately after the procedure, or as long as a year afterward. When it occurs, it can cause a heart attack. Drug-eluting stents are somewhat more likely to be followed by stent thrombosis than bare metal stents. Stent thromboses fortunately are rare, particularly if people take medicines to reduce the risk of blood clots.