Mechanical properties of the everolimus-eluting bioresorbable vascular scaffold compared to the metallic everolimus-eluting stent
Dalos et al. BMC Cardiovascular Disorders
Mechanical properties of the everolimus- eluting bioresorbable vascular scaffold compared to the metallic everolimus- eluting stent
Daniel Dalos 0
Clemens Gangl 0
Christian Roth 0
Lisa Krenn 0
Sabine Scherzer 0
Markus Vertesich 0
Irene Lang 0
Gerald Maurer 0
Thomas Neunteufl 2
Rudolf Berger 1
Georg Delle-Karth 3
0 Department of Internal Medicine II, Division of Cardiology, Medical University of Vienna , Waehringer Guertel 18-20, 1090 Vienna , Austria
1 Department of Internal Medicine, Division of Cardiology, Barmherzige Brüder Eisenstadt , Eisenstadt , Austria
2 Department of Internal Medicine, Division of Cardiology, University Hospital Krems , Krems , Austria
3 Department of Internal Medicine, Division of Cardiology, Krankenhaus Hietzing , Vienna , Austria
Background: Everolimus-eluting bioresorbable vascular scaffolds (BVS) represent an innovative treatment option for coronary artery disease. Clinical and angiographic results seem promising, however, data on its immediate procedural performance are still scarce. The aim of our study was to assess the mechanical properties of BVS by Optical Coherence Tomography (OCT) in clinical routine. Methods: Post-implantation OCT images of 40 BVS were retrospectively compared to those of 40 metallic everolimus-eluting stents (EES). Post-procedural device related morphological features were assessed. This included incidences of gross underexpansion and the stent eccentricity index (SEI, minimum/maximum diameter) as a measure for focal radial strength. Results: Patients receiving BVS were younger than those with EES (54.0 ± 11.2 years versus 61.7 ± 11.4 years, p = 0.012), the remaining baseline, vessel and lesion characteristics were comparable between groups. Lesion pre-dilatation was more frequently performed and inflation time was longer in the BVS than in the EES group (n = 34 versus n = 23, p = 0. 006 and 44.2 ± 12.8 versus 25.6 ± 8.4 seconds, p < 0.001, respectively). There were no significant differences in maximal inflation pressures and post-dilatation frequencies with non-compliant balloons between groups. Whereas gross device underexpansion was not significantly different, SEI was significantly lower in the BVS group (n = 12 (30 %) versus n = 14 (35 %), p = 0.812 and 0.69 ± 0.08 versus 0.76 ± 0.09, p < 0.001, respectively). There was no difference in major adverse cardiac event-rate at six months. Conclusion: Our data show that focal radial expansion was significantly reduced in BVS compared to EES in a clinical routine setting using no routine post-dilatation protocol. Whether these findings have impact on scaffold mid-term results as well as on clinical outcome has to be investigated in larger, randomized trials.
Bioresorbable Scaffold; Drug-Eluting Stent; Optical Coherence Tomography
Background
Drug eluting stents (DES) have shown to be highly
effective in the treatment of patients with coronary artery
disease [
1–3
] as neointimal hyperplasia after a vascular
injury was reduced compared to when bare metal stents
were used [
2, 3
]. Nevertheless, delayed or absent strut
endothelialization, persistent or acquired malapposition
and neoatherosclerosis of DES contribute to late stent
failure rates which are in the range of 1-2 % a year
within the first three years after implantation [
4–6
]. In
addition stent fractures especially at hinge points of the
coronary vessels and the lack of adaptive remodelling
processes in the artery wall can contribute to late events.
Bioresorbable vascular scaffolds (BVS) were developed
in order to reduce those potential adverse events after a
coronary intervention. After the bioresorption process is
completed there will not be any potential triggers for
late adverse events [
7
]. In contrast to vessels caged by
metallic stents, vessels transiently scaffolded by
bioresorbable materials are able to perform vasoconstriction
and vasodilation and therefore could also contribute to
better symptom control in patients with coronary artery
disease [
8–11
]. It was also shown that BVS are
characterized by a better conformability to the vessel compared
to metallic stents [12]. On the other hand it is still
unclear if the radial strength provided by BVS is sufficient
throughout various clinical scenarios. It has been shown
that metallic stents generate a larger acute lumen gain
compared to BVS, but scaffold/stent type was not
predictive for acute recoil [
13
]. Intravascular imaging data
describing device strength and expansion are still scarce.
The aim of the present study was to assess the
mechanical properties of BVS by Optical Coherence
Tomography (OCT) in clinical routine.
Methods
Patients
Between March and June 2013, 26 consecutive patients
underwent OCT immediately after implantation of 40
BVS (Absorb, Abbott Vascular, Santa Clara, CA, USA).
Elective patients as well as patients presenting with acute
coronary syndrome (ACS) were included. The OCT data
of these patients (...truncated)