Two-year clinical, angiographic, and serial optical coherence tomographic follow-up after implantation of an everolimus-eluting bioresorbable scaffold and an everolimus-eluting metallic stent: insights from the randomised ABSORB Japan trial
Selected in EuroIntervention by S. Brugaletta
Onuma Y, Sotomi Y, Shiomi H, Ozaki Y, Namiki A, Yasuda S, Ueno T, Ando K, Furuya J, Igarashi K, Kozuma K, Tanabe K, Kusano H, Rapoza R, Popma JJ, Stone GW, Simonton C, Serruys PW, Kimura T
EuroIntervention. 2016 Oct 20;12(9):1090-1101
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What is known
The fully bioresorbable coronary scaffold is a new device treatment for coronary artery stenosis which provides temporary mechanical support with drug elution, potentially without the limitations of permanent metallic implants. A recent meta-analysis of the four randomised trials (ABSORB II, III, Japan and China) comparing an everolimus-eluting polylactide bioresorbable vascular scaffold (BVS) and a cobalt-chromium everolimus-eluting metallic stent (CoCr-EES) demonstrated non-inferiority of BVS to CoCr-EES in terms of target lesion failure at one year, with a trend towards a higher incidence of very late events beyond one year. The present paper reports the 2-year OCT findings of the ABSORB Japan trial.
- In the ABSORB Japan trial, 400 patients were randomised in a 2:1 ratio to BVS (N=266) or CoCr-EES (N=134). A pre-specified OCT subgroup (N=125, OCT-1 group) underwent angiography and OCT post procedure and at two years.
- Overall, the two-year TLF rates were 7.3% and 3.8% in the BVS and CoCr-EES arms (p=0.18), respectively.
- Very late scaffold thrombosis (VLST) beyond one year was observed in 1.6% (four cases: all in non-OCT-1 subgroups) of the BVS arm, while there was no VLST in the CoCr-EES arm. In three cases, OCT at the time of or shortly after VLST demonstrated strut discontinuities, malapposition and/or uncovered struts. However, the vessel healing by two-year OCT was nearly complete in both BVS and CoCr-EES arms with almost fully covered struts, and minimal malapposition.
- The flow area by two-year OCT was smaller in the BVS arm than in the CoCr-EES arm, mainly due to tissue growth inside the device.
After the recent publication of the ABSORB II final data, much attention is on the performance of BVS. The present study gives in this regard important insights. First of all and taking into account that there was no statistical power for these endpoints, it is interesting to see that like the ABSORB II, the present study reports a numerically higher rate of TLF and VLST in the BVS than in the EES arms. However, OCT data showed that healing is not different between the two technologies with an overall low rate of malapposition and uncovered struts, with on the contrary strut discontinuity, malapposition and/or uncovered struts seen in three case of BVS VLST. These findings may suggest that BVS technology does not forgive any malapposed or uncovered strut and may reinforce the attention of the operator on the PSP steps (pre-dilatation, sizing and post-dilatation). Many data and many discussions will be on this topic to understand what was wrong and how to improve it. What is your opinion on this?