Drug eluting stents have reduced restenosis rates, and the need for further revascularisation after stenting, despite initial concerns over late stent thrombosis. This complication has been attributed to chronic inflammation and neoatherosclerosis induced by the durable polymers used in these stents. Biodegradable stents have been hypothesised to reduce this inflammatory burden, by degrading to leave a polymer/drug-free stent thereby removing the late risk of stent thrombosis.

The LEADERS  (Limus Eluted from A Durable versus ERodable Stent coating)  trial was a multicentre non-inferiority trial looking at the long-term clinical outcomes of biodegradeable polymer biolimus-eluting stents (BES) versus durable polymer sirolimus-eluting stents (SES) in adults with coronary artery disease. 1707 patients were randomly allocated to either the BES or SES arm, and the assessors were masked to this allocation.  At 4 year follow-up, there was non-inferiority in the composite primary end-point of cardiac death, myocardial infarction, or target-vessel revascularisation between the two groups (BES: 18.7% vs SES: 22.6%). There was also a relative risk of 0.62 of stent thrombosis in the BES group compared to the SES arm, which was due to a lower risk of stent thrombosis between years 1 and 4 of follow up (RR: 0.20, p<0.004).

This trial suggests overall non-inferiority of biodegradeable polymer BES compared with durable polymer SES over 4 years of follow-up and an 80% RR reduction when looking at very late definite stent thrombosis occurring 12 months following insertion. This suggests that clinical differences will only be appreciated between these two interventions at four years, and any subsequent superiority trial should have follow-up for at least this length of time.

Conclusions:

Four-year follow-up outcomes of the LEADERS trial suggest non-inferiority of the biodegradable biolimus-eluting stent.

• Giulio G Stefanini, Bindu Kalesan, Patrick W Serruys, et al. Long-termn clinical outcomes of biodegradable polymer biolimus-eluting stents versus durable polymer sirolimus-eluting stents in patients with coronary artery disease (LEADERS): 4 year follow-up of a randomised non-inferiority trial.  Lancet. Volume 378, Issue 9807, 3–9 December 2011, Pages 1940-1948