Experts say that although large-scale randomized controlled clinical trials of Absorb degradable scaffolds have not been successful, it does not mean that BVS is dead or that companies in the industry should postpone future research. But experts also reminded that the way forward for BVS is full of challenges.
After a few years of silence, Absorb’s manufacturer, Abbott, has re-launched with a new device. The thickness of the scaffold rod of the new device Esprit is only 100-120μm, which is thinner than Absorb’s 150μm.
At the CRT2020 meeting, "The Future of BVS Technology", Abbott revealed that their new product will be submitted IDE clinical trial "LIFE-BTK" application to the FDA. 225 patients with vascular lesions in the knee will be implanted with Esprit. The diameter of the diseased vessel is 2.5-3.75mm.
When the doctor asked whether the second-generation scaffold started clinical trials in the coronary arteries, Abbott replied, "If we do clinical trials in the coronary arteries, we will require imaging techniques to keep up to prevent the fault we made before. We need doctors enough understand and skilled use imaging technology, not necessarily OCT, and we have an imaging system to ensure accurate implantation of equipment, not just visual observation. " Some doctors objected, "Although imaging methods help to obtain more information about new devices, they are far from the point where imaging methods are necessary for PCI. Currently, the coverage of imaging methods in Europe is less than 20%." "We can't create a lot of things in the market, but the clinical results are only ‘non-inferior’." “Non-inferior "is only suitable when the cost does not increase."
The importance of clinical trials initiated by the investigator
The story of Absorb is well known. One-year clinical results show "non-inferior" to Xience, a permanent scaffold, but three-year results show a two-fold increase in clinical risk, especially target vascular myocardial infarction and advanced thrombosis, which eventually led to Absorb delisting.
Experts mentioned other BRS products at the meeting. So far, 6 BRS products have been approved by CE, but doctors have no enthusiasm to use these products after Absorb. The relevant new European clinical guidelines reduce the BRS to "limited to clinical trials (Recommendation III)."
Experts responsible for the development of European harmonized standards mentioned, "Why are the risks in our clinical trials not identified in pre-clinical testing? Especially the risks associated with the disassembly of the scaffold. When you look carefully at the results of the animal experiments, there are prompt messages, but these problems are difficult to solve. " The expert further emphasized, "clinical trials initiated by independent researchers are important and can provide information at the same time as clinical trials initiated by companies." "When we look back at the Absorb approval process, the curve of the target vessel failure rate is different for one year, but it is not statistically significant. But the increasing difference can be seen in the longer follow-up."
Abbott replied that doctors, researchers, and manufacturers are all trying to balance technology development costs and patient safety. Ideally, clinical trials should include thousands of patients followed up for more than five years, and mandatory imaging methods. The huge cost of such research makes such clinical trials unrealistic.
Gregg Stone (Icahn School of Medicine at Mount Sinai, New York) said, "Abbott may be upset, but BVS will never be accepted by doctors without passing large-scale clinical trials.”
He said, "You can conduct small trials of hundreds of people first, and use OCT imaging to achieve a high success rate of implantation. But large-scale clinical trials are necessary." Although BVS has various shortcomings, he still believes in the concept of degradable scaffolds. "Permanent stents are not free lunches. The incidence of adverse events of 2% per year has not been seen to be reduced in the later period. People aged 50 or 60 will still have to survive for 20-30 years after implanting scaffolds. That is a problem. We must develop degradable scaffolds. "
Some experts mentioned, "The scaffold design is improving. We have seen thinner stcaffolds, which bring hemodynamics and shear stress closer to the original physiological state. For example, Fanva Encore of Reva and Iron Bioabsorbable Scaffold of Lifetech ( Biotyx). "
Compile Author: szhotdog
Auditor: Vinjo
Source of this article: https://www.tctmd.com/news/newer-thinner-strut-abbott-scaffold-prompts-talk-bvs-comeback
