Advances in coronary stent technology have revolutionised the treatment of coronary artery disease (CAD) in current clinical practice. Novel stent platforms, such as biodegradable polymer drug-eluting stents (BP-DES) and polymer-free drug-eluting stents (PF-DES), have been developed in recent years to improve on patient outcomes of preceding generations of devices. These new-generation drug-eluting stents (DES) utilise a biocompatible or bioresorbable polymer coating to theoretically eliminate the risk of very late stent thrombosis (ST) associated with the current gold standard durable polymer drug-eluting stents (DP-DES). The permanent polymer coating of DP-DES has been shown to induce a chronic inflammatory response in the vessel wall leading to ST.
The performance of new-generation DES compared with DP-DES has not been well appraised in the literature. To summarise the latest clinical evidence, the present thesis included meta-analyses of randomised controlled trials (RCTs) comparing the safety and efficacy profiles of new-generation DES, namely BP-DES and PF-DES, with DP-DES. Subgroup analyses based on anti-proliferative drug, duration of dual antiplatelet therapy (DAPT), and length of follow-up were performed to ascertain if these variables might affect patient outcomes. Landmark analyses were also performed to evaluate late outcomes beyond 1 year. The overall rationale for the present thesis was to provide both qualitative and quantitative assessments of the clinical outcomes of new-generation DES to better inform the ongoing development of clinical practice guidelines for the use of coronary stents in patients with CAD.
In summary, new-generation DES and DP-DES conferred equivocal safety and efficacy profiles, with comparable risks of definite or probable ST, myocardial infarction (MI), cardiac death, all-cause death, target lesion revascularisation (TLR), and target vessel revascularisation (TVR). The theoretical advantages of BP-DES and PF-DES over DP-DES were not realised in the meta-analyses. Further RCTs with greater length of follow-up and larger patient population are warranted to determine the purported benefits of these novel stent platforms.