Mind The Gap: New Study Suggests Self-Apposing® Stents Completely Prevent Malapposition

In short

We’ve covered Stentys and its self-expanding, Self-Apposing® coronary stent on a number of occasions, the general sentiment of our pieces being that adapting to a vessel’s size seems to confer some benefits compared with conventional stent insertion. Now Stentys is trumpeting results from the foundational APPOSITION II clinical trial, which were published in the December issue of the American College of Cardiology’s journal, JACC Cardiovascular Interventions. And why wouldn’t the company make some noise when the results suggest their device completely prevents gapping between stent and vessel wall.


Stentys says its Self-Apposing® Stent addresses the stent-sizing dilemma that cardiologists are confronted with when treating heart attack patients. It fits into the contour of a blood vessel, and its shape and diameter adapt as the vessel dilates and the initial clot dissolves during the post-AMI phase, thus reducing the risk of malapposition and complications associated with conventional stents in this setting.

The newly published study, conducted between December 2009 and June 2010, compared the accurate implantation of the Stentys Self-Apposing stent vs. a conventional balloon-expandable stent in 80 patients treated for  ST-segment elevation myocardial infarction (STEMI). Placement accuracy was measured by high-definition imaging inside the artery (OCT) three days after treatment. The study results showed that 28% of the patients treated with conventional stents had a gap between the stent mesh and the artery wall (also called malapposition) whereas 0% of the patients with Stentys stents had malapposed stents. This result was statistically significant (p<0.001).

The manuscript, also available online is titled, “Self-Expanding Versus Balloon-Expandable Stents in Acute Myocardial Infarction: Results from the APPOSITION II Study”.

So does malapposition translate into a worse clinical outcome? Well, yes and no. Gapping is a known risk factor, but in this study Major Adverse Cardiac  Event (MACE) incidence at 6 months were not statistically significantly different between the two groups. Bigger numbers may ultimately change that, the Stentys group having 0% incidence vs 2.3% for the conventional stent group in this dataset.

Physician comments

“The results of this study remind us that malapposition, which increases the risk of heart attack recurrence, is very common when treating AMI with conventional stents. They also demonstrate that malapposition can be eliminated with the use of a STENTYS stent,” said Robert-Jan van Geuns, MD, PhD of Erasmus Hospital, Rotterdam, the Netherlands, investigator of the study and lead author of the publication. “This successful study was an important building block for the on-going APPOSITION clinical program designed to demonstrate optimal clinical outcomes with the Self-Apposing stent technology.”

Regulatory status

The STENTYS Self-Apposing Stent has been marketed in Europe since receiving CE Mark in 2010. It is not approved for marketing in the United States; however, the U.S. Food and Drug Administration recently approved an Investigational Device Exemption (IDE) to conduct a pivotal clinical study that will enroll up to 880 heart attack patients at 50 sites in the U.S. and worldwide.

Source: Stentys, Business Wire