Optical coherence tomography (OCT) measurements at 9-months’ follow-up
| Tomography measurements | ZES (n = 32) | SES (n = 36) | p Value |
| Cross sections (n) | 696 | 777 | – |
| Mean stent area (mm2) | 7.8 (1.7) | 6.6 (1.6) | 0.006 |
| Mean lumen area (mm2) | 5.6 (1.5) | 6.1 (1.7) | 0.35 |
| Mean NIH thickness (μm) | 251.2 (110.0) | 85.5 (53.4) | <0.001 |
| Mean NIH area (mm2) | 2.2 (0.8) | 0.7 (0.4) | <0.001 |
| Percentage of NIH | 27.9 (9.1) | 11.2 (7.1) | <0.001 |
| Heterogeneity score | 0.9 (0.8) | 1.1 (0.7) | <0.001 |
| Cross section with uncovered strut(s), n (%) | 18 (2.6) | 308 (39.6) | <0.001 |
| Cross section with uncovered strut ratio >0.3, n (%) | 0 (0.0) | 140 (18.0) | <0.001 |
| Presence of thrombi, n (%) | 0 (0.0) | 10 (27.8) | 0.001 |
Values are presented as mean (SD), unless stated otherwise.
Heterogeneity score was defined as the difference between maximal and minimal neointimal grade. (The status of NIH thickness at each cross section was divided into four grades; grade 0, uncovered strut to total stent struts; grade 1, NIH thickness <100 μm, which was not detected with intravascular ultrasound; grade 2, NIH thickness between 100 and 200 μm, which was between minimal thickness detectable using OCT and minimal mean thickness in bare metal stents; grade 3, NIH thickness over 200 μm.11 The grade was determined as minimal grade including ⩾10% of stent struts at each cross section.)
NIH, neointima hyperplasia; SES, sirolimus-eluting stent; ZES, zotarolimus-eluting stent.