Optical coherence evaluation of everolimus-eluting stents 8 months after implantation

The aim of this study was to evaluate detailed vessel response after everolimus-eluting stents (EES) implantation in human de novo coronary lesions by optical coherence tomography (OCT).

Between November 2008 and October 2009, 25 patients (14 men, 65.5±8.6 years) with de novo native coronary artery lesions were implanted with 30 EES, and OCT was performed at 8 months post-implantation.

Neointimal thickness (NIT) on each strut, strut apposition to the vessel wall, the frequency of struts surrounded by low intensity area and the incidence of intra-stent thrombus were analysed. To evaluate the radial unevenness of NIT, the difference between the maximum and minimum NIT (dNT) was calculated for each cross-section.

At 236±39 days after implantation, there were no major adverse cardiac events, nor target vessel revascularisation. A total of 5,931 struts was evaluated by OCT. The median NIT was 80 μm (25th and 75th percentile 50 μm and 140 μm) and average NIT was 100±74 μm. The number of neointima-covered struts was 5,834 (98.4%), and 31 (0.52%) struts showed malapposition without neointimal coverage. The number of struts surrounded by low intensity area was 452 (7.62%). Eleven EES (37%) showed full neointimal coverage. No intra-stent thrombus was detected. The average dNT was 108±77 μm.

Most EES struts were covered with uniform and thin neointima. The frequency of low-intensity neointima was very low, which may be a result of promoted vessel healing. These results may support improved clinical outcomes with EES in clinical trials.