Bioresorbable Vascular Scaffolds-Dead End or Still a Rough Diamond?

Abstract

Percutaneous coronary interventions with stent-based restorations of vessel patency have become the gold standard in the treatment of acute coronary states. Bioresorbable vascular scaffolds (BVS) have been designed to combine the efficiency of drug-eluting stents (DES) at the time of implantation and the advantages of a lack of foreign body afterwards. Complete resolution of the scaffold was intended to enable the restoration of vasomotor function and reduce the risk of device thrombosis. While early reports demonstrated superiority of BVS over DES, larger-scale application and longer observation exposed major concerns about their use, including lower radial strength and higher risk of thrombosis resulting in higher rate of major adverse cardiac events. Further focus on procedural details and research on the second generation of BVS with novel properties did not allow to unequivocally challenge position of DES. Nevertheless, BVS still have a chance to present superiority in distinctive indications. This review presents an outlook on the available first and second generation BVS and a summary of results of clinical trials on their use. It discusses explanations for unfavorable outcomes, proposed enhancement techniques and a potential niche for the use of BVS.

Keywords: acute coronary syndrome; angioplasty; bioresorbable vascular scaffold; drug-eluting stent; percutaneous coronary intervention.

Figure 1

Timeline of bioresorbable vascular scaffolds (BVS) resorption and its interactions with vessel wall [6,16]. Presented course of phases and events is a generalization for available BVS. Certain time points are specific for ABSORB BVS-see Table 1. Abbreviations: BVS, bioresorbable vascular scaffold; OCT, optical coherence tomography.

Figure 2

Comparison of incidence rate of major adverse events in randomized trials: (a) target lesion failure, (b) myocardial infarction, (c) cardiac death and (d) all device thrombosis. Figure presents data from ABSORB, AIDA, EVERBIO II and TROFI II trials. The circle diameter represents the number of patients in respective trials [17,19,66,67,68,69,70].

Figure 3

Comparison of the causes of device thrombosis in drug eluting stents (DES) and bioresorbable vascular scaffolds (BVS) [12].

Figure 4

Bubble graph showing the relationship between the mean number and length of the implanted scaffolds and the incidence of scaffold thrombosis at the 6–12 month follow-up. Only randomized controlled trials, or registries with ≥100 patients that reported the required scaffold implantation details and had a follow-up duration of 6–12 months were included. The circle diameter indicates the reported percentage of definite or probable scaffold thrombosis [19,80,81,102,107,112,113,114,117,119,120,124].