Inhibition of Neointima Formation by a Novel Drug-Eluting Stent System That Allows for Dose-Adjustable, Multiple, and On-Site Stent Coating

A novel paclitaxel-eluting porous carbon–carbon nanoparticle coated, nonpolymeric cobalt–chromium stent: Evaluation in a porcine model

OBJECTIVES

We aimed to evaluate the response of porcine coronary arteries to a novel paclitaxel-eluting porous carbon-carbon nanoparticle coated, nonpolymeric cobalt chromium stent.

BACKGROUND

Polymer based drug-eluting stents significantly reduce restenosis. However, the indefinite presence of polymer is thought to initiate and sustain inflammation and contribute to the occurrence of late complications.

METHODS

Sixteen carbon-carbon coated, nonpolymeric cobalt chromium stents with two different doses of paclitaxel (eight of each) were implanted in porcine coronary arteries. In addition, eight cobalt chromium stents coated with a biodegradable polymer were also studied. Animals were sacrificed 6 weeks after stent implantation and histomorphometric analysis was performed. Results were compared among the three groups of stents.

RESULTS

The cobalt chromium stents coated with carbon-carbon with low and medium doses of paclitaxel both showed acceptable performance characteristics, with respect to endothelialization, neointimal hyperplasia, percentage diameter stenosis, inflammatory response, and tendency to fibrin deposition, when compared to historical data with the Cypher stent. On the other hand, the stents coated with poly(lactide) and poly(lactide-co-glycolide) biodegradable polymers and 0.7 microg/mm2 paclitaxel showed poor performance. There was a significant tendency to poor endothelialization, greater neointimal hyperplasia, percentage diameter stenosis, greater inflammatory response, and tendency to fibrin deposition (P < 0.01 for all parameters).

CONCLUSIONS

This preclinical evaluation demonstrates the safety and efficacy of a novel cobalt chromium stent with a carbon-carbon coating and low and medium doses of paclitaxel.

Prevention of restenosis by a novel drug-eluting stent system with a dose-adjustable, polymer-free, on-site stent coating

AIMS

Drug-eluting stents (DES) represent a major advance in interventional cardiology. Along with the success shown, current DES also present limitations related to the presence of polymer-coating, fixed drug, and dose used. With the ISAR (Individualized Drug-Eluting Stent System to Abrogate Restenosis) project, a DES system has been developed that permits individualized choice of the drug and dose to use for the given patient. The objective of this prospective dose finding study was to assess the feasibility, safety, and efficacy of a polymer-free on-site stent coating with increasing rapamycin doses.

METHODS AND RESULTS

In this dose finding study, 602 patients were sequentially enrolled in four groups: microporous bare metal stent (BMS), DES stents coated with a 0.5, 1.0, and 2.0% rapamycin solution. The angiographic in-segment restenosis rate at follow-up angiography was the primary study endpoint. In-segment restenosis was significantly reduced from 25.9% with BMS to 18.9, 17.2, and 14.7% with 0.5, 1.0, and 2.0% rapamycin-eluting stents, respectively (P=0.024). Similarly, the need for target lesion revascularization at 1 year follow-up was reduced from 21.5% with BMS to 16.4, 12.6, and 8.8% with 0.5, 1.0, and 2.0% rapamycin-eluting stents, respectively (P=0.006).

CONCLUSION

The placement of polymer-free stents coated on-site with rapamycin is feasible and safe. Furthermore, a dose-dependent efficacy in restenosis prevention is achievable with this new DES concept.