medwireNews: Results of the large-scale INFINITY-SWEDEHEART trial provide further evidence that a bioadaptor implant is at least as good as a drug-eluting stent (DES) for managing people with coronary artery disease who need percutaneous coronary intervention (PCI).
The primary endpoint of target lesion failure at 12 months – a composite of cardiovascular death, target vessel myocardial infarction, and ischemia-driven target lesion revascularization – occurred in 2.4% of 1189 participants randomly assigned to receive a bioadaptor implant and 2.8% of 1192 assigned to a DES.
The difference in risk was 0.41 percentage points, which was below the noninferiority margin of 4.2 percentage points for demonstrating an absolute risk difference.
Noninferiority of the bioadaptor to the zotarolimus-eluting stent used in the trial was shown at 12 months, but there were also signs of a “potential superior clinical benefit after 6 months,” for the bioadaptor, write David Erlinge (Skåne University Hospital, Lund, Sweden) and co-investigators in The Lancet.
This timepoint is when the bioadaptor “unlocks,” they say, explaining that the device consists of three thin cobalt-chromium helical strands that are coated with a bioresorbable polymer. The latter contains an antiproliferative drug that is eluted as the polymer is resorbed over a period of 6 months. Once resorbed, the three helical strands are unlocked to enable vessel motion to be restored and provide dynamic support to the artery.
INFINITY-SWEDEHEART follows on from the BIOADAPTOR-RCT trial, which was conducted in 445 individuals with new coronary lesions warranting PCI and also showed noninferiority for the bioadaptor at 12 months versus a zotarolimus-eluting stent.
The aim of the present trial was thus to compare the two devices in a much larger and more representative population of people undergoing PCI, the researchers explain. Over a 3-year period, starting in September 2020, 2399 adults with CAD and an indication for PCI were prospectively recruited at 20 Swedish Centers.
The median age of the participants was 69.5 years, 76% were men, and around three quarters needed PCI for an acute coronary syndrome (ACS). They had up to three de novo lesions suitable for implantation with one device implanted per lesion, and all had received successful predilation.
“The trial had prespecified powered secondary endpoints to evaluate the bioadaptor’s effects on restoring haemodynamic modulation through provision of dynamic support to the diseased artery after unlocking at 6 months,” the researchers explain.
They add: “We found substantial clinical benefit for the bioadaptor group compared with the DES group in terms of target lesion failure, target vessel failure, target vessel myocardial infarction, ischaemia-driven target lesion revascularisation, and ischaemia-driven target vessel revascularisation in these 6-month landmark analyses.”
Indeed, considering the 6–12-month period, target lesion failure occurred in 0.3% of individuals in the bioadaptor group versus 1.7% of those in the DES group. Respective results for target vessel failure, target vessel myocardial infarction, ischemia-driven target lesion revascularization, and ischemia-driven target vessel revascularization were: 0.8% versus 2.5%, 0.1% versus 0.8%, 0.3% and 1.4%, and 0.8% versus 2.2%. The differences for all of these comparisons were significant in favor of the bioadaptor
Moreover, there were significantly fewer cases of definite or probable stent thrombosis (0.1 vs 0.3%), and target lesion failure only in people with ACS (0.3 vs 1.8%).
Commenting on the findings in a related editorial, Davide Capodanno (University of Catania, Italy) says that the results are promising and “hint at potential long-term advantages.” However, he also points out that the study had a few limitations.
“The event rate in the DES group was approximately a third of the expected rate (2.8% vs 7.5%), which complicates non-inferiority testing,” Capodanno points out.
He adds: “The investigators noted that a stricter non-inferiority margin, recalculated on the relative scale in response to the observed rate, would still support the trial’s hypothesis; however, a more realistic estimate would have required a larger sample size from the outset.”
Furthermore, “[a]lthough the separation of event curves between 6 months and 12 months is promising, the absolute difference in the event rate of target lesion failure remains small (at approximately 1%) and will require longer follow-up to confirm these findings.”
The findings are interim, the study’s investigators acknowledge, and further follow-up to 5 years is planned.
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