Favorable early vessel healing after everolimus-eluting stent implantation: 3-, 6-, and 12-month follow-up of optical coherence tomography

Background Although a prospective randomized control study revealed that 3-month dual anti-platelet therapy (DAPT) is safe and does not compromise the efficacy of everolimus-eluting stent (EES) in selected patients, detailed vessel healing at early phase after EES implantation has yet to be investigated in Japanese patients. Methods and results A total of 27 lesions in 19 patients treated with EES were serially evaluated by using optical coherence tomography (OCT) at 3, 6, and 12 months after stent implantation. In addition to standard quantitative OCT parameters, the percentage of stents with peri-strut low-intensity area (PLIA, a region around stent struts homogenously showing lesser intensity than the surrounding tissue, suggesting fibrin deposition or impaired neointima maturation) and that with in-stent thrombi were evaluated. There was a significant, but small increase in neointimal thickness (63 ± 17 μm; 83 ± 30 μm; and 111 ± 44 μm, respectively; p = 0.006) and small decrease in average lumen area (6.80 ± 2.57 mm2, 6.62 ± 2.58 mm2, 6.33 ± 2.58 mm2, p = 0.038) from the 3- to the 12-month follow-up. The incidences of uncovered and malapposed struts were low at 3 months and did not significantly change at 6 months and 12 months (3.01 ± 4.43; 2.45 ± 3.75; and 1.47 ± 3.16, p = 0.143, and 0.75 ± 0.65; 0.63 ± 0.73; and 0.58 ± 1.42, p = 0.162, respectively). Also, frequency of struts with PLIA was already low at three months and significantly decreased during the follow-up (6.4 ± 6.5; 4.6 ± 5.4; and 2.3 ± 3.3, respectively; p = 0.001). Conclusion Favorable vessel healing was achieved at 3 months after EES implantation without neointimal hyperplasia which was persistently suppressed up to 12 months.