Bioabsorbable polymer drug-eluting stents (BVS)* are safe and effective in patients with single coronary artery lesions after 2 years, with no cardiac deaths, retreatment of diseased lesions, or stent thromboses (blockages) reported. These are the conclusions of the two year outcomes of the ABSORB trial** published in an Article in this week's issue of The Lancet. The Article is one of four cardiology papers published in this edition, ahead of the American College of Cardiology meeting at the end of March.
The metallic stents used at the moment have a number of complications. There is a tendency for restenosis (re-blocking) of the blood vessels a number of months after implantation and it is not easy to resolve these secondary blockages. They also interfere with methods (such as magnetic resonance imaging and computed tomography) used to monitor the patency of the vessels. The new type of stent (BVS) was designed to avoid many of these problems.
In 2008, the first clinical trial of the BVS for the treatment of coronary atery disease, the ABSORB trial, showed some promising results. At 6 months, the device was shown to be safe and effective with no recorded stent thrombosis and a low (3.3%) rate of major adverse cardiac events (MACE). However, whether these benefits would persist over time was unknown.
In this study, Professor Patrick Serruys from the Thorax Center in Rotterdam, Netherlands and colleagues report the 2 year outcomes of the 30 patients involved in the original ABSORB trial and the results of their follow-up with various imaging methods including optical coherence tomography (OCT) and multislice CT.
Findings showed that at 2 years, the device was safe with only one major adverse event recorded, a heart attack, and no new adverse events occurred between 6 months and 2 years.
The authors also noted that by 2 years the biodegradable stent had been bioabsorbed, this should reduce the chance of restenosis. Indeed, the authors recorded a significant decrease in plaque area without a change in the blood vessel size (vessel area), which resulted in no additional restenosis (narrowing of the blood vessel).
The authors conclude: "All these findings need to be confirmed in larger studies, but this or similar devices could become of paramount importance for the restoration of vascular integrity in the treatment of flow-limiting plaque."
In an accompanying Comment, Antonio Colombo from the San Raffaele Scientfic Institute in Milan, Italy and Andrew Sharp from the Centro Cuore Columbus Hospital in Milan, Italy, say that: "We may indeed be looking at a major step forward in coronary stenting." But, they argue, larger trials in more complex patients are needed to show equivalent performance to the traditional drug-eluting stent, before these findings can be called a "breakthrough".
Professor Patrick Serruys, Thorax Center, Rotterdam, Netherlands.
T) +31 06 5367 1774 (Please note Professor Serruys is in Colorado this week, 6 hours behind UK time)
E) p.w.j.c.serruys@erasmusmc.nl
Dr Antonio Colombo, San Raffaele Scientfic Institute, Milan, Italy.
T) +39 02 481 2920
E) columbo@emocolumbus.it
For full Article and Comment see: http://press.thelancet.com/bioabsorbablestents.pdf
Notes to Editors:
*The BVS stent has a bioabsorbable structure made from polylactic acid and a coating that controls the release of a drug to prevent scar tissue formation. The BVS stent is designed to restore blood flow and be fully absorbed once the blood vessel has healed.
**The ABSORB trial involved 30 patients from four sites in Europe and New Zealand, who had one coronary artery lesion and were treated with the BVS stent. The trial investigated the efficacy, safety, major adverse cardiac events (MACE), and stent thrombosis at 2 years.
There are two other Articles in this week's edition, the links to which can be found below, along with their accompanying Comments.
For: Percutaneous coronary interventions for non-acute coronary artery disease: a quantitative 20-year synopsis and a network meta-analysis, plus accompanying Comment, see: http://press.thelancet.com/percutaneous20yearsynopsis.pdf
For: Safety and tolerability of SCH 530348 in patients undergoing non-urgent percutaneous coronary intervention: a randomised, double-blind, placebo-controlled phase II study, plus accompanying Comment, see: http://press.thelancet.com/sch530348.pdf
Journal
The Lancet