Another advantage is that they don’t show up on MRI or CT scans and nor do they cause problems for surgeons trying to find a metalfree segment to work on if patients require traditional re-interventional techniques.
However, Ron Waksman, associate director at Washington Hospital Center, USA, says: “I don’t think we have to convince doctors to use them. The issue would be to show that overall results in terms of performance are as good, or not inferior to, BMS or DES.”
Biodegradable polymer-coated stents.
The coating degrades shortly
after completion of drug elution
Two types of bioabsorbable stents exist – polymer and metal-based. Both must be capable of being safely absorbed by the body, without causing harm to the surrounding tissues.
A group from Poland presented nine- (angiographic) and 12-month (clinical) follow-up findings from fitting LUCChopin2, paclitaxel-eluting biodegradable polymer-coated stents into 115 patients.
One of the group, Dr Krzysztof Milewski, director of Animal Cath Lab, Upper-Silesian Heart Centre, Poland, told ESC Congress News: “Safety profile appeared excellent and we did not observe incidents of late stent thrombosis between 30 and 365 days of follow-up. The results were comparable to other commercially available stents.” The coating degrades shortly after completion of drug elution, leaving a metal stent covered with endothelium that does not irritate tissues.
The plan of Waksman and colleagues is to eliminate the entire metallic stent. In the Progress study, 61 patients were fitted with an AMS (Absorbable Metallic Stent), using magnesium in the alloy. All were tracked for 12 months, with nine patients followed for up to 28 months. The team found complete degradation of the stents and durability of the results at longer time points. This included restoration of the vaso-reactivity function of the vessel of the stented segment once the stent was absorbed.
“The artery had regained its capability to restrict and dilate,” says Waksman. “One of the promises of these stents is that once their job is done, they disappear and the artery regains its capabilities and, in these nine patients, this was the case.” He sees bioabsorbable stents as “the next frontier of stenting”, but emphasises the need to wait for better data before cardiologists can fully embrace this latest technological development.