Bioresorbable Stents

Usually elegant and sometimes ingenious, most innovations in interventional cardiology represent incremental advances. Quantum leaps are rare. A major transformation in practice occurred when bare metal stents (BMS) replaced balloon angioplasty, because stenting could scaffold intimal tears, reduce elastic recoil, and prevent negative remodeling.1 Another breakthrough occurred when antiproliferative drugs eluted from stents nearly eliminated the neointimal growth response to stent implantation.2 A negative consequence of drug-eluting stents has been a low incidence of late stent thrombosis3 caused by incomplete arterial healing and exposed metal struts left in contact with circulating blood.4 Because the need for vessel-wall support after coronary intervention may be temporary, bioresorbable coronary stents might represent a solution to prevent late stent thrombosis. Bioresorbable drug-eluting stents could provide temporary scaffolding when it is needed after coronary intervention, reduce the risk of restenosis, and completely disappear without leaving thrombogenic residua. If the devices are user-friendly and regulatory requirements are satisfied, bioresorbable stents could revolutionize the practice of interventional cardiology.Article see p 2301Bioresorbable stents were first implanted in animals in 1980. The first bioresorbable stent implanted in man was the Igaki-Tamai stent, a non-drug-eluting stent made of poly-L-lactide with a strut thickness of 170 μm that required a combination thermal self-expansion and balloon expansion for deployment. In the initial study of 15 patients with 19 lesions, there were no cases of stent thrombosis.5 In the second cohort of 50 patients, however, there were 3 cases of stent thrombosis, with 1 subacute event occurring at 5 days, 1 late event occurring after 30 days, and 1 very late event occurring after 1 year.6 Despite the pioneering efforts, concerns arose about the use of heat to expand the stent and possible thermal injury to the arterial wall.6The bioresorbable vascular scaffold (BVS) …