Can biodegradable stents improve heart outcomes?

This trial compared outcomes for sirolimus-eluting biodegradable stents (Orsiro) to everolimus-releasing durable stents (Xience) in patients with a need for more than 1 stent. It found that for patients having several stents placed after a heart attack, biodegradable stents had better outcomes.

While all heart attacks are concerning, ST-elevation myocardial infarction (STEMI) is particularly serious. This type of heart attack involves a complete blockage of one or more of the coronary arteries. Portions of the heart muscle will stop receiving blood during a STEMI event.

One treatment to prevent future heart attacks involves placing a stent to open the affected artery. There are several types of stents. Some of them elute, or release, medications within the coronary artery. Sirolimus and everolimus both reduce inflammation and discourage the tissue of the artery from regrowing over the stent. Patients with a past STEMI heart attack may need a single stent or multiple stents in several of the coronary arteries.

Stents are typically made of a rigid material such as plastic. However, some stents are biodegradable and are broken down by the body over time. Biodegradable sirolimus stents are successful for patients with a single stent placement. It is not clear how these stents perform for patients with blockages in more than one coronary artery.

This study included 145 patients with a previous STEMI who were having two or more stents placed. 72 patients had biodegradable sirolimus stents placed (group 1). 73 patients had everolimus-releasing durable stents placed (group 2). The researchers followed how many patients experienced a vessel failure. This included another heart attack related to the clogged artery, or having another procedure to open the artery. Patients were followed for two years.

There were significantly fewer vessel failures in group 1 compared to group 2 (2.8% vs. 18.7%) after 2 years. Also, fewer patients in group 1 had a fatal heart attack compared to group 2 (2.8% vs. 7.0%). There were also significantly fewer patients who needed a second procedure after 2 years in group 1 compared to group 2 (0% vs. 12.4%).

Patients having stents placed only at specific target areas had fewer vessel failures than patients having extensive stents (6.7% vs. 10.7%). Among these patients with targeted stents, there were also fewer failures with biodegradable stents than with durable stents (5.3% vs. 8.2%).

This study found that biodegradable sirolimus-eluting stents had better outcomes than durable stents for STEMI patients with stents placed in multiple blood vessels.

This research was funded by Biotronik AG, the manufacturer of Orsiro. The number of patients and follow-up period were small. Further studies are needed to confirm these results and evaluated the outcomes of these patients in the longer term.