Temporal Course of Neointimal Hyperplasia Following Drug-eluting Stent Implantation: a Serial Follow-up Optical Coherence Tomography Analysis

We sought to evaluate the temporal course of neointimal hyperplasia (NIH) after drug-eluting stent (DES) implantation, using serial optical coherence tomography (OCT). We identified 89 DES (82 patients) that had at least three consecutive cross-sections with a mean NIH thickness >100 µm on first follow-up OCT. Qualitative and quantitative changes in NIH were then assessed at a second follow-up OCT. NIH regression and progression were defined as a decrease or increase in mean NIH cross-sectional area >0.2 mm2, respectively, between the two studies. Between the first and second OCT there was a decrease in NIH in 29 lesions (32.6%), and an increase in NIH in 37 lesions (41.6%). Compared to patients with neointimal progression, those with regression showed lower levels of high sensitivity C-reactive protein (hsCRP) (p = 0.036) and higher levels of high-density lipoprotein (p = 0.012). Between the first and the second OCT, there were no significant changes in NIH morphologic patterns in 67 (75.3%) of 89 DES. In lesions with NIH regression, the evolution of heterogeneous to homogeneous neointima was observed, while the evolution of heterogeneous or homogeneous to layered neointima or the evolution of heterogeneous, homogeneous, or layered neointima to neoatherosclerosis was detected in lesions with NIH progression (p < 0.001). The hsCRP level at index procedure was significantly associated with neointimal regression in multivariate model (odds ratio 0.891, 95% confidence interval 0.796-0.999, p = 0.048). During late follow-up, OCT shows both NIH progression and regression that are paralleled by qualitative changes indicating increasing stability (in regression) and increasing instability (in progression).