Polymer-free drug releasing stent for patients with bleeding risk

This paper studied the safety and effectiveness of polymer-free and carrier-free drug-coated stent that releases umirolimus (Biolimus A9) in patients at high risk of bleeding. 

Stents are small devices placed in blood vessels to prevent obstruction of blood flow. They can be bare metal stents (mesh stent) or drug-eluting stents (stent that releases drug to stop blood from clotting and reblocking the vessel). Some patients undergoing percutaneous coronary intervention (procedure to insert stents) are at high risk for bleeding. Thus, these patients receive either a drug-eluting stent with shorter medication period or bare-metal stent followed by medication treatment. The substance that holds and releases the drug (polymer), however, can cause reactions such as inflammation in some patients.

A polymer-free drug coated stent that delivers umirolimus has been developed for patients at increased risk of bleeding. Polymer-free stents are suggested to be better for healing and associated with less side effects. 

1239 patients were randomly assigned to receive a umirolimus-coated stent. 1227 patients were randomly assigned to receive a similar bare-metal stent. All patients received dual antiplatelet therapy (medication to prevent blood clots) for 1 month.

After 390 days, 9.4% of patients who received the umirolimus stent had a heart attack, blood clot from stent, or death from heart related causes. 12.9% of patients who received the bare-metal stent had a heart attack, blood clot from stent, or death from heart related causes. Patients who received the umirolimus stent were 29% less at risk of heart attack, blood clot from stent, or death from heart related causes than patients who received the bare-metal stent.

5.1% of patients who received the umirolimus stent required revascularization (surgery to repair a blocked vessel) within 390 days. 9.8% of patients who received the bare-metal stent required revascularization. Patients who received the umirolimus stent were 50% less likely to require revascularization. 

The authors concluded that the new umirolimus stent was safer than the bare-metal stent in patients at high risk of bleeding.