The Safety and Efficacy Profile of Magnesium-Based Bioresorbable Coronary Stents as Compared to Poly-L-Lactic Acid-Based Bioresorbable and Contemporary Drug-Eluting Coronary Stents-A Systematic Review.

Background: Bioresorbable coronary stents (BRS) were designed with the aim of reducing the risk of late adverse events of permanent drug-eluting stents (DES) by dissolving once vessel patency had been restored and the requirement for acute mechanical support resolved. Bioresorbable poly-L-lactic acid (PLLA) scaffold designs, while initially appearing as promising technology, were unsuccessful in widespread clinical use due to an observed high rate of late stent thrombosis. Magnesium-based BRS (MgBRS) have provided an alternative to this original design and have shown promise in early-phase clinical trials. This review aims to address the clinical question: How does the current safety and efficacy evidence for MgBRS in all patients requiring percutaneous coronary intervention compare with the randomised data assessing PLLA-BRS and contemporary DES? Methods: Two parallel systematic reviews were performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, utilising MEDLINE, EMBASE and Web of Science: the first assessing clinical outcomes of all observational and randomised MgBRS trials, the second assessing clinical outcomes of PLLA-BRS versus DES in randomised clinical trials. The primary safety and efficacy outcomes collected were cardiac death, target vessel failure (TVF) and stent thrombosis. Results: A total of 3582 MgBRS patients (24 trials), 6370 PLLA-BRS and 5413 DES patients (16 trials) were included for analysis. Cardiac death was similar across all three stent designs in all time intervals. MgBRS performed similarly to contemporary DES and superiorly to PLLA-BRS at 12- and 24-month intervals with regard to TVF and stent thrombosis. Longer follow-up was suggestive of a poorer performance of MgBRS relative to DES, although with limited patient numbers. Conclusion: MgBRS appear to perform similarly to DES and superiorly to PLLA-BRS at 12 and 24 months in regard to key clinical safety and efficacy measures. Further randomised studies are required before recommending this technology for widespread clinical use over DES.