LAUSR

Introduction: The smaller size of LDL particle has suggested the development of endothelial dysfunction, atherosclerosis and in-stent restenosis (ISR), but little is known regarding the impact of LDL particle size on neointimal formation leading to ISR. Hypothesis: The LDL-C/Apolipoprotein B (Apo B) ratio < 1.2 has been reported to indirectly represent a high proportion of sdLDL. It was hypothesized that in-stent neointimal proliferation in LDL/ApoB < 1.2 patients may be excessive and unstable. Methods: In 135 patients, we investigated the relationship between the LDL particle size and neointimal characteristics using optical coherence tomography (OCT) and coronary angioscopy (CAS) during follow-up angiography after stent implantation. Results: ISR was identified in 35 patients, who had a significantly lower LDL/ApoB ratio (0.99±0.25 vs. 1.17±0.25; p < 0.01) and higher proportion of yellow grade 2 and 3 by CAS than non-ISR group (n=100). Among the non-ISR group, LDL/ApoB < 1.2 group (n=59) had a significantly larger neointimal volume by OCT, and higher proportion of yellow grade 2 and 3 by CAS compared with LDL/ApoB > 1.2 group (n=41) (Figure). Conclusions: Smaller size of LDL strongly associated with the neointimal proliferation, the neointimal instability and ISR evidenced by multimodalities, suggesting that smaller ratio of LDL/ApoB could be a surrogate marker for the neointimal characteristics after stent implantation.