Original Title: Polymer-free Drug-Coated Coronary Stents in Patients at High Bleeding Risk
Reference: Philip Urban et al. N Engl J Med. 2015 Oct 14. [Epub ahead of print].

High bleeding risk patients undergoing PCI usually receive conventional bare metal stents (BMS) to allow the shortest possible DAPT (dual antiplatelet therapy), usually a month long. This study assessed the biolimus A9 polymer-free coated stent (BioFreedom stent, Biosensors, Europe). The biolimus A9 (also known as umirolimus) is a highly lipophilic sirolimus analogue that is released in a month.

The double blind trial randomized high bleeding risk patients to the coated polymer free stent vs. a very similar conventional stent. All patients received only one month DAPT.

Primary safety end point (tested for non-inferiority and superiority) was a composite of cardiac death, acute myocardial infarction and in-stent thrombosis. Primary efficacy end point was clinically driven target vessel revascularization.

It included 2466 patients with more than one year follow up. In this period, 112 polymer-free DES patients (9.4%) vs. 154 (12.9%) BMS patients presented the safety end point (HR 0.71; CI 95% 0.56 to 0.91; p<0.001 for non-inferiority and p=0.005 for superiority).

During the same period, 59 patients (5.1%) in the polymer-free DES group vs. 113 (9.8%) in the BMS group underwent clinically driven target vessel revascularization (HR 0.5, CI 95% 0.37 to 0.69; p<0.001).

Conclusion
In those patients with high bleeding risk the biolimus polymer free A9 resulted superior to the conventional bare metal stent in terms of safety and efficacy with only one month of DAPT.

Editorial Comment
This study was designed to enroll high bleeding risk patients or patients that for any reason were no good candidates for prolonged DAPT. This high risk was reflected in a 7.2% bleeding rate (BARC 3 to 5) in both group, despite they only received one month DAPT. As a reference, the annual rate of bleeding in a standard population undergoing PCI is between 0,6 and 2,8%.
This new polymer free device is presented as a very good option for this group of patients that would have normally received conventional bare metal stents.