Stent-Like Hybrid on Track for Lofty Long-Term Goals in PCI

For percutaneous coronary intervention (PCI) on de novo lesions, the DynamX bioadaptor not only matched drug-eluting stents (DES) in early performance but seemed to keep stent-related events from accruing after 6 months, according to an interim analysis from INFINITY-SWEDEHEART.

In this randomized trial, the novel bioadaptor met criteria for noninferiority in terms of target lesion failure (TLF) at 1 year, a composite endpoint counting cardiovascular death, target vessel myocardial infarction, and ischemia-driven target lesion revascularization (2.35% vs 2.77% with DES, P<0.0001 for noninferiority), reported David Erlinge, MD, PhD, of Sweden’s Lund University and Skåne University Hospital.

Notably, a signal of superiority emerged between 6 and 12 months: prespecified landmark analyses suggested the device’s improvements over DES during this later window in both TLF (0.3% vs 1.7%, HR 0.19, 95% CI 0.06-0.65) and target vessel failure (TVF; 0.8% vs 2.5%, HR 0.35, 95% CI 0.16-0.79), Erlinge told the audience at the Transcatheter Cardiovascular Therapeutics (TCT) meeting. A full trial report was simultaneously published in The Lancet.

“Evidence from the large-scale INFINITY-SWEDEHEART RCT [randomized controlled trial] confirms the results from the BIOADAPTOR RCT trial and suggests bioadaptors may represent the long-awaited solution to flatten the event curve following PCI, marking a significant advancement in coronary interventions,” Erlinge concluded.

However, the value proposition of bioadaptor technology — that it can resolve the issue of stent-related adverse events that have persisted despite decades of innovation — will take long-term data to confirm. Erlinge said his team is planning to follow the INFINITY-SWEDEHEART cohort regularly until they reach the 5-year results.

TCT discussant Joanna Wykrzykowska, MD, PhD, of University Medical Center Groningen in the Netherlands, said she was “very interested in what the real long-term outcomes are at 5, 10 years. If this shows superiority, then I think we have a new contender.”

The DynamX bioadaptor is a stent-like coronary implant, comprising chained helical strands on a bioresorbable polymer coating. After the first 6 months, the metallic strands are unlocked from the lost coating and the separated strands intended to maintain vessel support while restoring hemodynamic modulation — which is backed by the 6-12 month “significant flattening” of event curves in the present report.

Earlier, the smaller BIOADAPTOR RCT had shown that the DynamX performed just as well as the Resolute Onyx DES in terms of TLF and even resulted in plaque stabilization and regression.

“[T]he bioadaptor seems to achieve the aim of addressing key deficiencies of contemporary PCI technologies. Specifically, addressing the shortcomings of stents and leave-nothing-behind technologies, the bioadaptor differs from both technologies through dynamic radial support of the vessel, improving vasomotion, adaptive remodelling, and vessel function after the bioadaptor is unlocked,” Erlinge’s group explained.

Erlinge reported that in INFINITY-SWEDEHEART, the DynamX was also found to reduce TLF in the acute coronary syndrome (ACS) group after 6 months (0.3% vs 1.8%, HR 0.17, 95% CI 0.04-0.74). In fact, the event reduction appeared consistent across prespecified subgroups, including complex lesion subsets (e.g., left anterior descending [LAD] artery, small vessels, long lesions) known to be associated with more restenosis and complications over time.

“These results could suggest a benefit of the bioadaptor in high-risk subgroups that might particularly benefit from bioadaptive PCI, such as patients with acute coronary syndrome, with LAD lesions that are susceptible to pulsatility and torsion, and with lesions in smaller reference vessel diameter that might benefit from vessel adaptive remodelling to offset late lumen loss,” the investigators wrote.

Wykrzykowska cautioned that the trial still excluded important subgroups, such as left main disease, bypass grafts, and chronic total occlusions.

INFINITY-SWEDEHEART was a single-blind trial that included adults up to 85 years of age who were indicated for PCI and had up to three de novo coronary lesions based on a Swedish registry. Investigators recruited 2,400 people from 20 Swedish sites.

Participants were randomized 1:1 to either the DynamX bioadaptor or a zotarolimus-eluting DES (Resolute Onyx and Onyx Trustar).

Baseline and lesion characteristics were similar between groups. The overall cohort was a median 69.5 years old and 24% were women. Over three-quarters of participants presented with acute coronary syndrome, and around 14% had a previous PCI.

The LAD was the target vessel in about half of cases. Just over 10% of people had two or more target vessels. Lesions were largely either class B1 or B2/C. Diameter stenosis averaged just over 87%.

Erlinge’s team reported that device safety was favorable in the trial, given low device thrombosis rates in both bioadaptor and DES arms (0.7% vs 0.5%).

Study authors did note that their observed event rates were lower than expected in both groups. They also acknowledged that they did not collect data on race and ethnicity for the trial.