Time dependent vascular and myocardial responses of a second generation, small vessel, paclitaxel-eluting stent platform.

OBJECTIVES

The purpose of this study was to evaluate the time-dependent vascular and myocardial responses to a second-generation, small vessel (< or =2.5 mm) paclitaxel-eluting stent (PES) platform.

BACKGROUND

Small caliber coronary vessels present complex challenges for percutaneous coronary intervention (PCI) and are associated with lower technical success and inferior long-term efficacy. A next-generation, highly deliverable PES may improve clinical outcomes in small vessels.

METHODS

Sixty single stents were implanted in noninjured coronary arteries in 30 domestic swine (one TAXUS Liberté small vessel PES (svPES) and one Liberté small vessel bare metal stent (svBMS) in each animal). Ten animals each were allocated to 30-, 90-, and 180-day follow-up groups; final quantitative angiography and necropsy were performed. Samples of myocardium, liver, and kidney were processed and evaluated for pathology. Radiography and either histopathology or scanning electron microscopy were performed on all the explanted stented vessels.

RESULTS

There were no stent-related deaths or downstream myocardial pathology. Both the svPES stent and its svBMS control demonstrated complete strut tissue coverage and complete endothelialization at all timepoints, and there was no evidence of macro- or microscopic thrombus or stent fracture. Medial smooth muscle cell content was markedly reduced in all the svPES groups compared with that in the svBMS controls.

CONCLUSIONS

The small diameter paclitaxel-eluting TAXUS Liberté stent has a safe and predictable biologic vascular response in the noninjured swine model. This device warrants further investigation targeting the currently poorly met clinical need for small vessel PCI.