Stents are used to open the narrowed heart vessels (coronary arteries) without the need to open the chest.
For further knowledge about history, uses and types of stents, and their use in emergency or planned procedures to open diseased coronary arteries, please have a look at these articles (1-3):
1. Article Coronary stents: Historical development, current status and ...
2. Article Cardiovascular Stents: A Review of Past, Current, and Emerging Devices
3. Chapter Advanced Stents for Cardiovascular Applications