Treatment of in-stent restenosis. Actual status and future perspectives

In-stent restenosis is an increasing problem due to the frequent use of cor onary stent as a form of percutaneous revascularization. The global inciden ce is near to 28%, and it is well document that a neointimal hyperplasia is its principal mechanism. The most commonly related factors for its appeara nce are diabetes mellitus, a longer length of the original lesion, a smalle r diameter of the reference vessel, the left anterior descending artery loc ation and a smaller luminal diameter at the end of the procedure. Due to a different long term evolution in-stent-restenosis has been classified as fo cal or diffuse, according to the length of the restenotic lesion (focal < 1 0 mm and diffuse greater than or equal to 10 mm). Some strategies have been proven for its treatment, but no randomized-contr olled trials have been published comparing these different treatments. In f ocal in-stent-restenosis the practice of a conventional balloon angioplasty is associated with high initial clinical success with a favourable long te rm evolution (target lesion revascularization between 11-15%). But on the c ontrary, in diffuse in-stent-restenosis, in spite of a high initial success rate, an elevated target lesion revascularization has been detected at the follow-up (up to 43%). Other proved such as aterectomy or excimer laser ar e associated with a significant procedural non-Q-wave infarction (near to 9 %) and a long term target lesion revascularization during follow-up (23-31% ). The implantation of an additional stent has been performed with low proc edural complications and with a long term target lesion revascularization n ear to 27%. Patients treated with intracoronary radiation as a complementar y technique seem to have a better long term evolution than those having had the other strategies alone. In conclusion, in-stent-restenosis is a new and progressively more frequent problem, requiring complex treatment and of which as been established. Com parative controlled studies need to be performed in order to determine the best treatment for this new entity.