Polymer-free versus permanent polymer drug eluting stents in coronary artery disease: A meta-analysis of 10 RCTs with 6575 patients

BACKGROUND Permanent polymer drug eluting stents (PP-DES) may induce inflammation of the vessel wall due to the existence of the polymer, which may delay intimal healing. Polymer-free DES (PF-DES) that eliminate the polymeric carrier may potentially lead to safer DES. However, the safety and efficacy of PF-DES remains controversial. METHODS Randomized controlled trials comparing PF-DES with PP-DES were searched in online database including MEDLINE, Excerpta Medica Database (EMBASE) and Cochrane Library. Studies reporting late lumen loss (LLL), all-cause death, myocardial infarction (MI), target lesion revascularization (TLR) and late stent thrombosis (LST) were enrolled and quantitatively analyzed. RESULTS Ten studies enrolling 6575 patients were included in this meta-analysis. The PF-DES showed a benefit in reducing all-cause death (OR = 0.77, 95% CI: 0.61 to 0.98, P = 0.03) and long-term LLL (weighted mean difference (WMD) -0.16 mm, 95% CI: -0.22 to -0.11 mm, P < 0.001), while no superiority was found in reducing short-term LLL (WMD 0.03 mm, 95% CI: -0.07-0.13 mm, P = 0.57), MI (OR = 1.12, 95% CI: 0.19 to 23.18, P = 0.39), TLR (OR = 1.19, 95% CI: 0.42 to 3.38, P = 0.83) and LST (OR = 0.92, 95% CI: 0.05 to 5.71, P = 0.74). CONCLUSION PF-DES showed benefits in reducing long-term LLL and mortality compared with PP-DES, but no superiority was found in short-term LLL, MI, TLR and LST. These findings provide a sound basis for the wide application of PF-DES in the future.