Implantation of drug-eluting stents
Since the turn of the century, we have had metal stent platforms coated with a polymer containing an antiproliferative drug that is slowly released after implantation, for an average of 20-30 days. This slow release inhibits the proliferative process associated to scarring after implantation, drastically reducing the incidence of re-stenosis after treating coronary lesions with stents to 2-10%, depending on the type of treated lesion.
Everything learnt with inert metal stents was applicable to DES, as the platform remained unchanged, and navigability and production were better. The number of coronary patients treated with DES increased sharply in all clinical circumstances (stable and unstable angina, silent angina, myocardial infarction, etc.). However, a concern arose at the famous European cardiology congress in 2004 in Barcelona, which was the possibility of increasing the incidence of tardive thrombotic occlusions secondary to excessive proliferative inhibition, which would leave the metal stent without a neointimal coating and in contact with blood, and could favour thrombosis. The process was studied in depth and new antiplatelet and antithrombotic drugs designed new strategies for preventing tardive complications.
The current incidence of tardive thrombosis is similar for both DES and inert stents, around 1-2%. Another improved aspect is the chosen drug. Sirolimus was initially found to be more effective than Plaquitaxel. The “Limus” family, primarily Everolimus, is now preferred. The release system has also been improved, and in some cases takes place without polymers, which could also help to favour thrombosis. This release system is abluminal, towards and in contact with the arterial wall. The diversity of DES diameters and lengths has also progressed, and DES is now the best cardiological instrument for treating coronary disease.