Stent design and its impact on healing

Experts at a Biotronik-sponsored symposium gathered on day 2 of EuroPCR to discuss how bioabsorbable polymer and ultra-thin stent design impacts on healing and to present new data on Orsiro, the industry’s first hybrid drug eluting stent (DES).

Launched in 2011, Osirio combines passive and active components. PROBIO passive coating encapsulates the stent and minimizes interaction between the metal stent and the surrounding tissue. BIOlute active coating contains a highly biocompatible polymer that delivers a limus drug via a bioabsorbable matrix. This hybrid coating is layered on the high performance PRO-Kinetic Energy stent platform, renowned for its advanced thin-strut stent design and outstanding deliverability.

Stephen Windecker, Department of Cardiology, Swiss Cardiovascular Center and Clinical Trials Unit, Bern University Hospital, Switzerland, in an overview progress with metallic drug-eluting stents (DES) said: “Strut thickness, stent design and geometry as well as abluminal vs. circumferential coating of polymer all play an important role in the determination of acute thrombogenicity. Preclinical and autopsy studies point to a benefit of biodegradable polymer DES with respect to chronic inflammatory reactions and the Orsiro PLLA-based Sirolimus eluting stent shows very low inflammatory response secondary to its slow-degrading polymer. However, only long-term clinical studies will be able to reveal the relative merits of stent design on patient outcome.”

Orsiro results

The next speaker Dr. Juan F. Iglesias, Lausanne University Hospital (CHUV), Switzerland, opened by acknowledging that PCI with durable polymer DES in high risk patients has been associated with higher rates of stent failure, including increased risk of ISR, TVR and late/very late ST. He added: “Biodegradable-polymer DES have been recently developed to overcome this limitation, with the advantage to potentially reduce the risk of late adverse clinical events including very late ST and shorten the duration of dual anti-platelet therapy (DAPT).”

Dr Iglesias also discussed promising results from an ad hoc analysis of the BIOSCIENCE trial, the largest published investigator-initiated trial evaluating the safety and efficacy of Orsiro to date; the results of the multi-center, randomized, controlled all-comers non-inferiority study were first published in The Lancet.

A sub-group of 407 patients suffering from acute ST-segment election myocardial infarction (STEMI) revealed that patients with this potentially fatal condition benefited from treatment with Orsiro, a sirolimus-eluting stent with a bioabsorbable polymer, in comparison to an everolimus-eluting stent with a durable polymer (DP-EES). At one year, the primary endpoint Target Lesion Failure (TLF) occurred in seven (3.4 percent) patients treated with Orsiro and 17 (8.8 percent) patients treated              with DP-EES.

Additionally, new three-year data from the BIOFLOW-II randomized controlled trial was presented. BIOFLOW-II was a prospective, international, multi-center, randomized trial evaluating the safety and efficacy of Orsiro compared with Xience Prime. These positive long-term results demonstrated Orsiro’s long-term healing properties following treatment of patients with coronary artery disease or high risk disease.

“Further analysis of the high-risk subgroups in the BIOFLOW and BIOSCIENCE trials reveals Orsiro’s effectiveness in treating challenging cases,” stated lead investigator of the BIOSCIENCE trial Dr. Thomas Pilgrim, University of Bern, Switzerland. “Orsiro’s noted benefit for STEMI patients in particular is worth further examination in a randomized trial.”

In addition to Dr. Iglesias’s presentation on Orsiro, the BIOTRONIK symposium also focused on current and future developments in coronary intervention. Dr Michael Joner, CVPath, Washington DC, USA, described preclinical work comparing bioabsorbable to permanent polymer DES, addressing the biocompatibility and healing aspects of these technologies. Dr. Pilgrim examined the current controversy regarding dual antiplatelet therapy (DAPT) in combination with bioabsorbable polymer DES implantation. Finally, Dr. Michael Haude, Lukaskrankenhaus, Neuss, Germany, discussed the ongoing BIOSOLVE-II clinical trial, which will establish the safety and performance of BIOTRONIK’s drug-eluting absorbable magnesium-based scaffold.