Comparison of a Novel Biodegradable Polymer Sirolimus-Eluting Stent With a Durable Polymer Everolimus-Eluting Stent: 5-Year Outcomes of the Randomized BIOFLOW-II Trial.

Objectives: The authors aimed to compare long-term data of an ultrathin cobalt-chromium stent with passive silicon carbide coating and an active biodegradable polymer that releases sirolimus (O-SES) (Orsiro, BIOTRONIK, Bülach, Switzerland) with the durable polymer-based Xience Prime everolimus-eluting stent (X-EES) (Abbott Vascular, Santa Clara, California).

Background: Biodegradable polymer stents have been developed aiming to overcome long-term detrimental effects of durable polymer stents, ultimately leaving a bare-metal stent in the vessel.

Methods: This multicenter, assessor-blinded trial randomized 452 patients with 505 lesions to either O-SES or X-EES in a 2:1 fashion. Endpoints at 5 years were target lesion failure (TLF), its components, and stent thrombosis.

Results: TLF occurred in 10.4% (n = 30) of O-SES patients versus 12.7% (n = 19) of X-EES patients (p = 0.473), overall stent thrombosis occurred in 0.7% (n = 2) versus 2.8% (n = 4) (p = 0.088), and definite stent thrombosis in 0% versus 0.7% (n = 1) (p = 0.341). Post hoc analysis was performed in diabetic patients (n = 128) and vessels ≤2.75 mm (n = 259). In diabetic patients, the O-SES group had numerically more target lesion revascularizations (13.5% vs. 4.5%; p = 0.138), but fewer cardiac deaths (1.3% vs. 6.9%; p = 0.089) and stent thrombosis (0% vs. 6.9%; p = 0.039). In small vessels, the O-SES group had a significantly lower 5-year mortality (3.7% vs. 11.3%; p = 0.022).

Conclusions: At 5 years, the biodegradable polymer O-SES demonstrated low TLF rates comparable to the durable polymer X-EES, confirming its long-term safety and performance. Particularly encouraging is the absence of definite stent thrombosis.