there are two basic types of stents that cardiologists use to treat blockages in coronary arteries. both are made of metal but one type is coated with a polymer that has drugs embedded in it that can help prevent the re-narrowing of the blockage that occurs in 20-30% of the blockages treated with the "bare metal" stents. these "drug-eluting" stents were a major step forward in the technology used to treat blockages. but they also carry with them a need for longer periods of antiplatelet therapy (aspirin plus clopidogrel) than was required with the bare metal ones. it's these two characteristcs (reducing the risk of re-narrowing balanced against the need for long-term antiplatelet treatment) that influence which stent a cardiologist might use to treat blockages. for example blockages with a greater likelihood for re-narrowing include very long blockages in smaller arteries. cardiologists might more likely use a drug-eluting stent for these while using bare-metal ones for more discrete blockages in large arteries. this is just one example. cardiologists consider many patient factors (for example is someone willing to take clopidogrel for a year) as well as technical factors when making these decisions. if you find out that you need a stent ask your cardiologist how and why he/she will make these decisions.
how does a doctor choose the kind of stent needed to treat heart blockages?