Qualitative assessment of neointimal tissue after drug-eluting stent implantation: Comparison between follow-up optical coherence tomography and intravascular ultrasound

Background: Characterization of neointimal tissue is essential to understand the pathophysiology of in-stent restenosis after drug-eluting stent (DES) implantation. We compared the morphological characteristics of neointimal tissue as assessed by optical coherence tomography (OCT) and intravascular ultrasound (IVUS) in patients treated with DES. Methods: A total of 243 patients (250 lesions) underwent follow-up OCT and IVUS after DES implantation. Results: Mean time interval from DES implantation to follow-up OCT/IVUS was 12.0 ± 9.3 (range 2.8-68.5) months. Percent neointimal hyperplasia (NIH) cross-sectional area (CSA) was calculated as (NIH CSA/stent CSA) × 100 for receiver-operating characteristic analysis of NIH detection by IVUS; the optimal cutoff value of percent NIH CSA was 14.7%, as determined by OCT (sensitivity 0.887, specificity 0.790). Neointimal hyperplasia was detected by both OCT and IVUS in 121 of 250 lesions and categorized as homogenous (OCT n = 74, IVUS n = 107), heterogeneous (OCT n = 34, IVUS n = 4), or layered (OCT n = 13, IVUS n = 10). Of the 121 NIH lesions, nonhomogenous NIH was detected in 14 (11.6%) by IVUS and 47 (38.8%) by OCT. Optical coherence tomography and IVUS assessments of NIH morphology showed a moderate correlation (P < .001, r = 0.455); however, assessments differed in 37 (30.6%) of 121 lesions. Conclusion: Optical coherence tomography-assessed NIH morphology might be different from that by IVUS in about 30% of the lesions that were treated with DES implantation.