Ultrathin coronary stent with biodegradable coating shows promise
9 September 2014
A new generation of coronary artery stent that combines a
biodegradable component with an ultrathin metal scaffold showed
promising results compared with the current gold standard stent in a
large clinical trial.
The BIOSCIENCE trial was presented at the ESC Congress 2014, and
published simultaneously in The Lancet.
The experimental stent “represents the next logical step in stent
refinement by combining an ultrathin platform with a polymer that
completely degrades,” said BIOSCIENCE investigator Thomas Pilgrim,
MD, from the Swiss Cardiovascular Center at University Hospital, in
Coronary artery stents are metal scaffolds that are inserted to
unblock the small arteries supplying the heart. For well over a
decade, stents have been drug-eluting, meaning coated with
medication to prevent re-blockage of the artery. Earlier
drug-eluting stents were coated with non-biodegradable polymers and
had thick stainless steel struts, both features that have been
linked with an increased rate of complications.
In contrast, the experimental stent combines both a biodegradable
polymer and an ultrathin cobalt-chromium strut, the thinnest strut
Subjects in the trial had coronary artery disease and were
randomly assigned to receive either the experimental stent (n=1063)
or the standard stent (n=1056) during percutaneous coronary
They were then followed for 12 months, with the primary endpoint
of the study being a composite of cardiac death, heart attack caused
by a re-blockage in the treated artery, and the need for
revascularisation of the treated artery within the study period.
The trial was designed to show non-inferiority of the
experimental stent compared to the standard stent and indeed, the
composite endpoint occurred in 6.5% versus 6.6% of subjects
The non-inferiority for the experimental stent is noteworthy, in
that “it matched the outcomes of one of the safest and most
effective new generation drug-eluting stents,” explained Dr.
Pilgrim. “Because of the low event rates of contemporary stents it
is becoming increasingly difficult to establish superiority of newer
stents in clinical trials,” he added.
However, in a subgroup of patients presenting heart attack, the
experimental stent showed superiority over the standard stent, with
the primary endpoint occurring in only 3.3% versus 8.7% respectively
(relative risk [RR] 0.38, p=0•024).
The study was not powered to assess differences in this subgroup,
“therefore we cannot exclude that these findings are due to chance
alone,” he said. “But future studies will need to explore whether
such differences can be reproduced in this patient population, which
is at highest risk for ischemic adverse events.”
The study was supported by Biotronik and the Swiss National