Currently coronary stents are used in more than 90% of PCI procedures world wide for treatment of Coronary artery disease.
The dramatic increase in the use of Bare Metal Stents identified a new problem, restenosis occurring within the stent, In-stent restenosis(ISR). ISR is clearly correlated with the degree of stent-induced injury to the vessel wall, strut thickness, patient factors (diabetes, acute coronary syndromes, etc.), and lesion characteristics (small luminal diameter vessel, bifurcation, ostial, restenotic as well as venous graft lesions). In addition, chronic foreign-body inflammatory response as well as gradual long-term corrosion of the metallic stent may have roles in the process of ISR. Drug eluting stents (DES) have reduced ISR and target lesion revascularization (TLR) compared with BMS and launched a revolution in the interventional treatment of symptomatic CAD. However, enthusiasm for this technology has recently been dampened by concerns about late stent thrombosis (LST), incomplete endo- thelialization, coronary artery spasm, and abnormal vasomotor function. Thus, focus has been brought onto the structure and composition of stents and stent coatings with particular interest in how the vessel responds to the foreign device and development of devices with improved biocompatibility and long-term patient outcomes.
