The DynamX bioadaptor represents a breakthrough in coronary stent implant technology. In this interview, Callan Emery speaks to Dr Mirvat Alasnag, MD, Head of the Catheterization Laboratory, King Fahd Armed Forces Hospital, KSA about this innovative device, which differs from traditional stents by “uncaging” the treated vessel after an initial healing period. The interview explores the DynamX bioadaptor’s unique design, mechanism of action, clinical data, and potential to improve long-term outcomes for patients with coronary artery disease.
Callan Emery: Can you briefly explain what the DynamX bioadaptor is and how the stent’s design and mechanism of action differ from traditional drug-eluting stents or bare-metal stents?
Dr Mirvat Alasnag: The DynamX™ bioadaptor is the first coronary implant technology with a unique mechanism of unlocking the bioadaptor frame after polymer resorption over 6 months, uncaging the vessel while maintaining dynamic support to the vessel. It aims to achieve the acute performance of drug-eluting stents (DES) with the advantages of restoration of vessel function.
It consists of three thin metal alloy helical strands held together temporarily by a bioabsorbable coating to provide strength when opening an artery blockage. Unlike traditional stents, after the period of healing and coating resorption in the first six months, the bioadaptor unlocks and the helical strands separate, thereby restoring hemodynamic modulation of the vessel and establishing more natural and dynamic support of artery motion and function.
The bioadaptor can also expand slowly over time along with the artery in order to maintain good blood flow.1 Recent findings also show stabilization and even shrinking of plaque volume in arteries treated with the bioadaptor.2
Callan Emery: How many of these stents have you implanted and are you involved in any clinical study of this stent?
Dr Mirvat Alasnag: So far, we have used it in a dozen patients with varying pathologies and presentations including ACS [acute coronary syndrome], STEMI [ST-elevation myocardial infarction], and CCS [chronic coronary syndrome or stable ischemic heart disease]. We are currently recruiting for the BioRestore trial.
Callan Emery: Can you explain how the unique “uncaging” mechanism of the DynamX device works after the polymer resorbs over 6 months? What are the potential advantages of this “uncaging” mechanism?
Dr Mirvat Alasnag: The DynamX bioadaptor is a metal (cobalt-chromium) implant with a drug-eluting bioresorbable polymer that supports the coronary artery during healing, with radial strength similar to drug-eluting stents. Though it initially functions like a traditional drug-eluting stent while the coronary artery heals (~3 months). Resorption of the basecoat polymer (similar to dissolving sutures) on the DynamX bioadaptor is designed to naturally resorb over 6 months. This enables the helical strands to unlock and separate while maintaining the established blood flow lumen, and growth of functional muscle cells around the struts. This allows the bioadaptor to unlock and the vessel to uncage, thus permitting the artery to move and function more naturally in response to the heart’s hemodynamic needs (such as during exercise). This unique mechanism of action has also been shown to restore (a) the ability for positive adaptive remodelling, (b) vessel function such as pulsatility and vasomotion, and (c) allow for the vessel’s return towards baseline angulation.
Results of a randomized controlled trial also showed significant reduction in target lesion failure and target vessel failure compared to a third generation DES out to 2 years. The patency of treated vessels were also significantly greater for DynamX bioadaptor with the difference in late lumen loss and percentage diameter stenosis reaching statistical significance.
Drug-eluting stents cage the coronary arteries and prevent a return to more natural motion and function, precluding natural hemodynamic modulation.
Callan Emery: Are there any specific patient populations that may particularly benefit from this stent technology? Are there any contraindications?
Dr Mirvat Alasnag: This is a very good question. While the clinical data shows effectiveness and safety across the patient population and vessel types, the data shows particularly differentiated superiority for the LAD [left anterior descending artery]. It is not too surprising considering that the LAD is a very long vessel that experiences a lot of motion with every heartbeat. In fact, a study by a team at the University of Chicago, Illinois showed that the proximal and distal ends of the LAD often rotate in different directions.
Another patient population that could benefit greatly are younger patients. The idea with restoration of more natural artery motion, function, and ultimately blood flow, is to flatten the major adverse cardiac event (MACE) curve. With the stent-related MACE rate well documented at 2-3% growth annually without plateau, you can imagine the tremendous risk these patients face in their lifetimes for revascularization, hospitalization, and even cardiac-related death.
Finally, patients who seek to reclaim an active lifestyle may also benefit from the restoration of vessel pulsatility and hemodynamic modulation that results from the device’s unique unlocking mechanism of action.
Callan Emery: How does the deployment procedure for the DynamX stent differ, if at all, from implanting a traditional stent?
Dr Mirvat Alasnag: The deployment procedure for the DynamX bioadaptor is no different from that of a traditional drug-eluting stent.
Callan Emery: What clinical data or trials have evaluated the performance and efficacy of the DynamX stent so far? How does it compare to current gold-standard stents?
Dr Mirvat Alasnag: The latest data on DynamX was presented at a late-breaking clinical session during the EuroPCR 2024 conference in Paris. This was based on the two-year results from the BIOADAPTOR Randomized Controlled (1:1) Trial (RCT), comparing the DynamX bioadaptor system to standard of care Resolute OnyxTM Drug-Eluting Stent from 34 centres in Japan, Europe, and New Zealand. The results, for the first time, demonstrate significant reduction in adverse events and clinical advantage of the DynamX bioadaptor in target lesion failure (TLF) and secondary endpoint of target vessel failure (TVF) driven by sustained low event rates with DynamX compared to a two-fold increase in DES.
An earlier, single-arm, open-label mechanistic study included imaging analysis and first confirmed restoration of vessel function and motion. It is notable that there were zero deaths attributed to the device or procedure and zero definite/probable stent thrombosis out to the final 3-year follow up period.
Callan Emery: What are the potential risks or complications associated with the use of this stent, and how do they compare to the risks of other stent types?
Dr Mirvat Alasnag: The potential peri-procedural risks at first seem similar to drug-eluting stents, but as I mentioned earlier, the clinical outcomes are different between the technologies. The outcomes of the randomized controlled trial already show a flattening of the TLF curve for DynamX from 1 year to 2 years (1.8% to 2.3%) while it continues to rise linearly as expected for the comparative drug-eluting stent (2.8% to 5.5%).
Callan Emery: How does the DynamX bioadaptor stent’s design address the issue of late stent thrombosis, which can be a concern with some stent types?
Dr Mirvat Alasnag: The unique design of the DynamX bioadaptor allows for restoration of more natural vessel motion and function as observed in the restoration of arterial pulsatility and motion. This allows for more natural blood flow in the uncaged artery, not only in the treated segment but also proximal and distal to it, and decreased risk of the factors that can lead to late thrombotic events.
I also want to clarify that this device, the DynamX bioadaptor, is very different from bio-resorbable scaffold (BRS) devices. BRS were plagued by late stent thrombosis rates that were significantly worse than for DES. This was driven by several factors including thick struts, malapposition, and long resorption times. The DynamX bioadaptor is comprised of thin (71µm) struts that are implanted similarly to DES. The helical strands unlock and separate at 6 months and are safely embedded in healthy, functioning neointima just like DES (98% strut coverage at 12 months).
Callan Emery: What kind of long-term follow-up or monitoring is recommended for patients receiving this type of dynamic stent?
Dr Mirvat Alasnag: The follow up is per our standard protocol for all patients with CAD to optimize ASCVD risk factors and determine duration of DAPT [dual-antiplatelet therapy]. Those enrolled in the BioRestore trial obviously have the follow up per protocol for a total of 12 months and assessing clinical endpoints of TLF; cardiovascular death, target vessel myocardial infarction, clinically indicated target lesion revascularization (CITLR), per ARC-2.
Callan Emery: What are the potential implications of this technology for improving long-term outcomes and quality of life for patients undergoing coronary stenting procedures?
Dr Mirvat Alasnag: The great long-term potential of the DynamX bioadaptor is to flatten and lower the MACE curve over the patient’s lifetime. The unique restoration of vessel motion and function also allows for improved blood flow in response to cardiac exertion, so patients may experience less symptoms of their cardiac disease, engage in more of the activities they enjoy and carry less of their constant anxiety burden.
References:
- Verheye, S. et al. Twelve-month clinical and imaging outcomes of the uncaging coronary DynamX bioadaptor system. EuroIntervention 2020;16:e974-e981.
- Saito, S, et al. First randomised controlled trial comparing the sirolimus-eluting bioadaptor with the zotarolimus-eluting drug-eluting stent in patients with de novo coronary arty lesions: 12-month clinical and imaging data from the multi-centre, international, BIOADAPTOR- RCT. The Lancet Nov 2023; 1-13.
