Hiroki Katoh

Delayed Neointimalization on Sirolimus-Eluting Stents : 6-Month and 12-Month Follow up by Optical Coherence Tomography

BACKGROUND Sirolimus-eluting stents (SES) have incomplete neointimal coverage at 6-month follow up as determined with optical coherence tomography (OCT). The long-term detailed changes of neointima in SES remains to be clarified. METHODS AND RESULTS Serial changes in neointimal coverage of SES from 6 months to 12 months using OCT were examined. Of 21 SES in 13 patients, OCT was used to visualize 2,321 stent struts at 6 months and 2,285 stent struts at 12 months. The frequency of struts without neointimal coverage decreased from 6 months to 12 months (from 10.4 to 5.7%). The frequency of malapposed struts decreased from 6 months to 12 months (from 1.7 to 0.2%). The average thickness of the neointima increased (from 112 +/-123 to 120 +/-130 microm). The frequency of struts located at the side branch orifice without neointima decreased (from 4 out of 17 (24%) to 0 out of 17 (0%)). Complete coverage with neointima was observed in 14% (3 of 21 SES) at 6 months, and 24% (5 of 21 SES) at 12 months. CONCLUSIONS Additional neointimal coverage was observed between 6 and 12 months, with a small increase in the neointimal thickness. The incidence of complete coverage, however, was still low at 12 months. These findings suggest delayed neointimalization on SES.

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

Objective 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). Design, setting and patients 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. Main outcome measures 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. Results At 236±39 days after implantation, there were no major adverse cardiac events, nor target vessel revascularisation. A total of 5931 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 5834 (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. Conclusions 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.