Bioresorbable vascular scaffold: a step back thinking of the future

The introduction of coronary stents in 1986 revolutionized interventional cardiology. First introduced to address issues of acute recoil and coronary artery dissections, bare metal stents (BMS) soon proved superior to balloon-only angioplasty in randomized controlled trials [1, 2]. Later, the introduction of stents eluting cytotoxic/cytostatic drugs addressed the incidence of late restenosis [3] and, after another 10 years, a number of modifications to the design, polymer, eluted drug, and stent struts’ geometry led to devices with improved biocompatibility, radio-opacity, radial strength, and deliverability. Despite all these improvements over the years, both BMS and drug-eluting stents (DES) have some limitations. In fact, their permanent structure hinders surgical myocardial revascularization and physiological vessel remodeling and represents a permanent possible source of inflammation, which in turn is felt to expose patients to the risk of late stent thrombosis (a non-negligible hazard with an incidence up to 1–2% annually with first-generation DES and a mortality that may reach up to 30%) [3]. In an attempt to minimize the long-term mechanical and biological stress caused by a permanent implant, fully bioresorbable stents (BRS) were introduced in 2012 as a novel promising approach. The aim of this new technology was to treat coronary stenosis by providing transient vessel support with drug delivery capability without the long-term limitations associated with vessel caging.
In this issue of the journal, Orlik et al. [4] report 1-year clinical outcomes with the ABSORB BRS (Abbott, Santa Clara, USA) in 138 patients with coronary artery disease. The study design is observational, comparing clinical outcomes with everolimus-eluting bioresorbable scaffolds against those with everolimus-eluting metallic DES. Propensity-score matching was used in an attempt to adjust for differences in baseline patient risk between the treatment groups. Their main finding was that, in terms of major adverse composite endpoints, comparable results were found between bioresorbable vascular scaffolds and DES (7.2% vs. 11.15%; p = 0.17). The target vessel revascularization rate was 2.9% in both groups. Except for the periprocedural period, there were no deaths or myocardial infarctions in the BRS group. There was no stent thrombosis in either group.
In interpreting the data, a number of limitations must be considered. First, although propensity score matching by...


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