Long-term clinical outcomes after bioabsorbable polymer- and durable polymer-based sirolimus-eluting stents implantation： two-year follow-up results from a large single-center database

Background Several clinical trials have shown that sirolimus-eluting stents significantly reduce the risk of restenosis after percutaneous coronary intervention （PCI）. The FIREBIRD stent （coated with durable polymer） and the EXCEL stent （coated with bioabsorbable polymer） are two different types of sirolimus-eluting stents made in China; both have been approved for clinical use in China by the State Food and Drug Administration. The mid-term （6-month） angiographic and clinical results of both stents have been confirmed exciting perspective outcomes. However, it is unclear whether there are differences in the long-term safety and efficacy between the two types of stents in daily practice. Methods All consecutive patients undergoing elective PCI with EXCEL or FIREBIRD stents between June 1,2006 and December 31, 2006 at Fu Wai Hospital in Beijing were included. Patients were classified from the index admission according to stent types （EXCEL or FIREBIRD） used. Clinical and procedural risk factors were collected prospectively. With propensity score matching without replacement, the frequency of major adverse cardiac events （MACE, a composite of death, myocardial infarction or target vessel revascularization） and stent thrombosis during a 2-year follow-up period were compared between the two groups. Results A total of 474 patients were treated with EXCEL, and 640 were treated with FIREBIRD. Three hundred and ninety-seven EXCEL patients were matched to 397 FIREBIRD patients, 2-year risk-adjusted MACE rates were 6.1% in EXCEL group and 7.6% in FIREBIRD group （HR 0.84, 95%CI0.50-1.43）, whereas the respective rates for mortality, myocardial infarction and target-vessel revascularization were 2.3% vs 2.8% （HR 0.74, 95%CI0.30-0.85）, 1.8% vs 1.3% （HR 1.41,95%CI 0.45-4.43） and 2.5% vs 4.0% （HR 0.62, 95%CI0.28-0.37）, respectively. Cumulative incidence of stent thrombosis at 2 years was 1.8% in the EXCEL group vs 1.3% in the FIREBIRD group （P=0.5610）, whereas the rate of very late stent thrombosis was 0.5% vs 1.3% （P=0.2550）. Conclusions Results from this long-term, relatively large size, single-center study showed that both of the EXCEL and the FIREBIRD sirolimus-eluting stent had similar and lower incidence of MACE after PCI in daily practice.