Background: Drug-eluting stents (DES) have been shown to significantly reduce clinical events and angiographic restenosis in the treatment of coronary artery disease (CAD). This study was conducted to assess the long-term efficacy and safety of the polymer-based sirolimus-eluting cobalt-chromium Firebird 2 stents in the treatment of patients with CAD.
Methods: This first-in-man study using the Firebird 2 stent is a prospective, historically-controlled multicenter clinical study, which enrolled 67 patients with CAD who were treated with the sirolimus-eluting cobalt-chromium stent (Firebird 2, Microport Shanghai, Firebird 2 group), compared to another 49 patients treated with a bare cobalt alloy stent (Driver, Medtronic, control group). Continued 2-year clinical follow-up was performed after getting the initial 6-month angiographic and 1-year clinical follow-up. The incidence of major adverse cardiac events (MACE) including cardiac death, reinfarction and target lesion revascularization (TLR) and stent thrombosis were compared between the two groups.
Results: All patients in the Firebird 2 group (100.0%) and 48 patients in the control group (98.0%) completed the 2-year clinical follow-up. At the 1-year follow-up the use of the Firebird 2 stent was highly effective, resulting in a significant 94% decrease of TLR (26.5% in the control group and 1.5% in the Firebird 2 group, P<0.0001). A significant difference in TLR was maintained at 2-year follow-up, Firebird 2 group 1.5% and the control group 31.3% (P<0.0001). Between 1- and 2-year post-stenting, no more TLR occurred in the Firebird 2 group compared with two cases in the control group (P>0.05). There was a 1.5% incidence of MACE at 1- and 2-year follow-up in the Firebird 2 group, compared with 26.5% and 33.3% in the control group, respectively (all P<0.0001). The cumulative 1- and 2-year MACE free survival rates were 98.5% in the Firebird 2 group vs 73.5% and 66.7% in the control group (log rank P<0.0001). No case of stent thrombosis occurred during 2-year follow-up in the Firebird 2 group, compared with one case that suffered a definite stent thrombosis in the control group at 19-month post-stenting: this patient presented with unstable angina pectoris and was treated by balloon angioplasty.
Conclusions: Compared with the bare cobalt alloy stent, the Firebird 2 sirolimus-eluting cobalt-chromium stent is safe and effective in treating patients with CAD. The use of this stent was associated with a sustained clinical benefit and significantly lower rate of TLR and MACE up to 2 years post-stenting.