Non-Polymer-Based, Rapamycin-Eluting Stents to Prevent Restenosis

• Binary angiographic restenosis at follow-up angiogram
  

• Target vessel failure (all-cause death, myocardial infarction, or revascularization of the target lesion)
  

In-stent restenosis remains the major problem limiting the efficacy of coronary stenting. Either sirolimus or paclitaxel drug-eluting stents have been demonstrated to decrease neointima proliferation resulting in a remarkable reduction of restenosis rate. However, despite the outstanding results achieved with this novel approach to restenosis, some caveats still remain. Although sirolimus markedly decreased the restenosis rate among diabetic patients in SIRIUS trial, the benefit of treatment was modest in those diabetics treated with insulin as well as with lesions longer than 15 mm located in vessels smaller than 2.5 mm. Additionally, in a recent study it was reported that the restenosis rate in high-risk lesions such as coronary bifurcations still remains a problem Data from patient populations other than those enrolled in randomized trials suggest even more caution in the evaluation of the impact of DES on restenosis in the “real world”, where the operator must deal with in-stent restenosis, bifurcation lesions, chronic total occlusions, small vessels, and long lesions. The identification of some of the traditional risk factors for restenosis as important predictors for in-DES restenosis could be explained as an insufficient inhibition of tissue reaction and neointimal growth by the antiproliferative action of the specific drug or dose used. This leads to the inference that an individualized approach should be adopted by tailoring the choice and the dosing of eluting drug(s) according to the specific lesion or patient characteristics. On the other hand, although drug-eluting stents are currently considered as the most effective way to reduce in-stent restenosis, their widespread use is hampered by the high costs. Therefore, it is important to develop new methods and techniques that would result in a more effective prevention of in-stent restenosis while being available for a larger number of patients. These considerations as well as the proven efficacy of rapamycin in lowering the rate of coronary restenosis, support the rationality of the concept of on-site coating of stents in the catheterization laboratory with individualized doses of rapamycin after the clinical and the angiographic profiles of the patient scheduled to coronary stenting have been determined