Bioabsorbable polymer drug-eluting stents (BVS) are safe and effective in patients with single coronary artery lesions after two years, with no cardiac deaths, retreatment of diseased lesions or stent thromboses reported, according to the outcomes of the ABSORB trial published in the March 12 issue of the Lancet to be presented at the American College of Cardiology (ACC) conference this month in Orlando, Fla.
The BVS stent from Abbott Vascular has a bioabsorbable structure made from polylactic acid and a coating that controls the release of a drug to prevent scar tissue formation, the researchers said. The BVS stent is designed to restore blood flow and be fully absorbed once the blood vessel has healed.
In 2008, the first clinical trial of the BVS for the treatment of coronary artery disease, the ABSORB trial, showed some promising results. At six months, the device was shown to be safe and effective with no recorded stent thrombosis and a low (3.3 percent) rate of MACE. However, the ABSORB authors noted that whether these benefits would persist over time was unknown.
In this study, Patrick Serruys, MD, PhD, from the Thorax Center in Rotterdam, Netherlands, and colleagues reported the two-year outcomes of the 30 patients involved in the original ABSORB trial 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 two years. Follow-up was done with various imaging methods, including optical coherence tomography (OCT) and multidetector CT.
At two years, the investigators said that the device was safe with only one major adverse event recorded (heart attack) and no new adverse events occurred between six months and two years.
The authors also noted the biodegradable stent had been bioabsorbed, which should reduce the chance of restenosis. The authors also recorded a significant decrease in plaque area without a change in the blood vessel size, which resulted in no additional restenosis.
Serruys and colleagues conclude that "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 commentary, Antonio Colombo, MD, from the San Raffaele Scientfic Institute in Milan, Italy, and Andrew Sharp, MD, from the Centro Cuore Columbus Hospital in Milan, Italy, wrote: "We may indeed be looking at a major step forward in coronary stenting."
However, Colombo and Sharp argued that 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."