Third-generation drug-eluting stents (DES) have thinner struts than their older counterparts, yet results so far show that the newer devices have comparable strength and visibility on angiography, presenters said Saturday during a CRT 2021 Virtual session.
Sripal Bangalore, MD, of the New York University School of Medicine, presented on the efficacy of ultrathin-strut DES.
Thick-strut stents are commonly known to increase the chance of thrombogenicity. The success of thinner, second-generation DES, whose struts measure between 70 and 100 microns, in the last decade is well-documented.
Bangalore wondered whether ultrathin stents, with struts measuring less than 70 microns, provide significantly better patient outcomes.
While Bangalore mentioned that radial strength is a concern in these ultrathin stents, he noted that Biotronik’s Orsiro stent, the only ultrathin-strut stent available in the U.S., has not been shown to be angiographically inferior to thicker second-generation DES. He gave Orsiro’s performance in the BIOFLOW II clinical trial as an example. The Orsiro stent has a strut size of 60 microns for stent sizes measuring 3.0 mm or less.
Besides being angiographically similar to second-generation DES, Bangalore said he wanted to see whether these newer ultrathin-strut stents were “clinically superior.”
In 2018, Bangalore led a meta-analysis of 10 randomized clinical trials of 11,658 patients and compared three ultrathin-strut DES (Orsiro, MiStent, and BioMime) to thicker-strut second-generation DES.
He found that when compared to the older generation of DES, the ultrathin-strut DES produced a 16% reduction in target lesion failure (TLF), a 20% reduction in myocardial infarction and improved 1-year clinical outcomes.
Since then, other meta-analyses and 3-year data from clinical trials, including BIOFLOW-V, have shown that ultrathin-strut DES enable “a significant reduction in cardiovascular events even beyond the one-year time point,” Bangalore said.
But thinner might not always mean better.
“I would say there is a line beyond which there may not be any incremental benefit,” Bangalore said, and future studies will have to explore whether “that line is 60 microns, 50 microns, etc.”
In his presentation, Michael Haude, MD, PhD, of Städtische Kliniken Neuss Lukaskrankenhaus GmbH, Germany, gave an update on the status of the drug-eluting magnesium bioresorbable scaffold device market.
The leader in the market is Biotronik’s Magmaris. According to Haude, the device, approved in 2016, has been implanted in “more than 3,500 patients” across clinical trials and registries.
Data from BIOSOLVE-II (n=117), the combined cohort of BIOSOLVE-II/III (n=174) and BIOSOLVE-IV (n=1,071) which all studied the device, outline a “very favorable data set” for the Magmaris, Haude said.
Importantly, the data confirm the device’s prolonged safety and efficacy.
At the 5-month follow up for BIOSOLVE-II, there was a TLF rate of 8.0% and a 0.0% rate of definite or probable scaffold thrombosis. In the much larger BIOSOLVE-IV group, there was a TLF rate of 4.3% and a 0.5% rate of definite or probable scaffold thrombosis at 12 months.
In recent years, Biotronik has developed BIOmag, a modified alloy that has a higher tensile strength and a better fracture density score than the alloy used in the Magmaris device.
According to data from Biotronik, the BIOmag registered an 80% reduction in fracture density in tests.
Biotronik uses this alloy in its latest-generation scaffold, DREAMS 3G. The device ranges in size from 2.5 to 4.0 mm, and offers reduced strut thickness for each.
Importantly, the device’s radial force was not compromised in the process of technological advancement.
Using data from Biotronik, Haude noted that the device’s “radial force was significantly improved throughout the whole range of diameters” and is now on a “comparable level” to the Orsiro DES. Visibility of the device has also improved.
While physicians are still waiting for clinical data to be published, the DREAMS 3G device is currently being studied in the BIOMAG-1 pivotal trial for CE Mark approval. The prospective, multi-center, single-arm trial is currently recruiting up to 115 patients.
Bernardo Cortese, MD, of San Carlo Clinic Milano, Italy, thanked Haude for “keeping the dream of bioabsorbable scaffolds” alive and well.