If you have had a metal stent (whether it be bare metal or drug eluting) implanted in a blood vessel, it is very unlikely that the stent will set off the metal detector at airport security.
The Transportation Security Administration (TSA) has guidelines on implanted medical devices. Your stent should not present any problems with an airport metal detector, but visiting the TSA website before you travel can keep you up-to-date on any guideline changes and give you further peace of mind. If you do have implanted medical devices (such as a pacemaker) that could present a problem with the metal detector alarm at security, let a TSA security officer know and request a private screening if necessary. This will normally consist of a clothed pat-down.
In addition, in some instances, you may receive a stent card when you are discharged from the hospital after receiving your stent. A stent card provides information about the stent that was placed in your heart artery. Carry this stent card in your wallet or purse so that if you are asked for medical health information this can be presented.