Tuesday, August 3rd, 2010

Bioplastics: Absorbable Stent Saves Your Life, then Disappears!

Heart stents, a common medical tool used to open clogged arteries and improve blood flow, have traditionally been made of metal and remain in place in the patient permanently. While usually effective, metal stents are not perfect and can sometimes cause problems – including thrombosis or clotting – and are not always the answer for patients with advanced coronary artery disease.

But now Abbott Laboratories – which leads the metal stent market – has developed a new stent they call “Absorb” which is made of a corn-based bioplastic called polylactic acid (PLA). This same material is being used in a number of  other ways, including food packaging, textile fibers and even gift cards.

The stent, coated with a drug called everolimus, is named “Absorb” because, unlike metallic stents, once the vessel can remain open without extra support, the stent is slowly metabolized by the body until it is completely dissolved. Since a permanent implant is not left behind, the vessel ultimately can move, flex and pulsate in a manner similar to an untreated vessel. Officially called “bioresorbable vascular scaffold (BVS),” the stent takes about 18 months to fully dissolve. According to a Fast Company article, unlike metal stents, “Abbott’s Absorb would… also let cardiologists use noninvasive heart imaging for follow-up care.” 

A March 2010 Abbott press release announced positive news concerning the 101 patients enrolled in the second phase of an Absorb trial. “Patients treated with Abbott’s bioresorbable vascular scaffold (BVS), under clinical investigation in Europe, demonstrated no cases of blood clots (thrombosis), no need for repeat procedures (ischemia-driven target lesion revascularization) and a very low rate of major adverse cardiac events…These results build on the long-term success Abbott has seen with the BVS technology in the first phase of the Absorb trial, which has generated positive data on 30 patients out to three years.”  Results of the study were also published in The Lancet.

While more trials with larger patient populations will be conducted over the next three years before the new stent can win government approval in Europe or the United States, Dr. Patrick Serruys, professor of interventional cardiology at the Thoraxcentre, Erasmus University Hospital, Rotterdam, the Netherlands, and principal investigator for the Absorb trial states:

“The continuing positive results of the Absorb trial and the clinical benefits demonstrated to date by Abbott’s bioresorbable technology show promise that a bioresorbable scaffold is on its way to becoming a clinical reality and will be the next revolution in interventional cardiology.”

A revolution in cardiology made possible by a corn-based bioplastic.


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