ReviewAbsorb bioresorbable vascular scaffold: What have we learned after 5 years of clinical experience?
Introduction
Several bioresorbable scaffolds have been proposed and have now reached clinical testing but only for the Absorb (Abbott Vascular, Santa Clara, CA, USA) bioresorbable vascular scaffold (BVS) a considerable amount of clinical data is available to date [1], [2]. First-in-man studies on small and highly selected cohorts, using multimodality intracoronary imaging, have confirmed the timing of the reabsorption process and suggested good safety and efficacy [3], [4]. These initial favorable results have been challenged by “real world” registries showing high Scaffold Thrombosis (ST) rates [5], [6], [7], [8]. With the fast approaching milestone of 100.000 implanted Absorb BVS and the prediction that more than 50% stents will be BVS by 2017, it is essential to learn from critically reviewing the many studies and registries and the only one randomized trial available to possibly correct current pitfalls in the implantation technique of such devices [9].
Section snippets
The device
The ABSORB BVS is constituted by a poly-l-lactide (PLLA) backbone covered by a 1:1 mixture of an amorphous matrix of poly-d,l-lactide (PDLLA) and the anti-proliferative drug everolimus (100 μl/cm2) [2]. The first proof of concept study (ABSORB cohort A) used a prototype soon replaced by the 1.1 version, storable at room temperature, with the same high strut thickness of 150 μm but greater resistance to acute and early recoil [10], [11], [12] and greater conformability and flexibility provided by
Future perspectives
As always for novel technologies, the first device introduced into the market has many aspects that can be improved. The Absorb strut thickness (150 μm, similar to the first-generation metal DES) has been claimed to be potentially responsible for higher rates of adverse events. The next generation scaffolds, as the DESsolve C, the MeRes and the Biolute BRS have a strut thickness of 100 μm, 100 μm and 108 μm, respectively. This will represent a major improvement, if they maintain an adequate radial
Conclusions
Recent registries have challenged the initial claim that BVSs are immune from Scaffold Thrombosis. Although prudence and careful monitoring are essential in the adoption of a potentially revolutionary technique and further large randomized studies are warranted to support the widespread use of BVS in clinical practice, more favorable results have been obtained with the optimization of the implantation technique and wider use of intracoronary imaging tools.
The following are the supplementary
Conflict of interest
The authors report no relationships that could be construed as a conflict of interest.
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