Background: Lipid rich plaque (LRP) content has been shown to decrease after high-pressure balloon-expandable stent placement. LRPs are quantified by the lipid core burden index (LCBI) on near-infrared spectroscopy (NIRS). We aim to evaluate the changes in LRP content during sequential steps of non-urgent percutaneous coronary intervention (PCI) using low-pressures. Methods:A total of 10 patients with a LCBI>200 on pre-stenting NIRS and successful PCI with the self-apposing stent were included. Quantitative coronary angiography was used to assess luminal diameters. IVUS-NIRS was performed pre-stenting after initial pre-dilatation, post-stenting and after post-dilatation to assess the LCBI and the plaque burden to evaluate plaque modification. IVUS-NIRS is analyzed for all stented segments including proximal and distal stent edges using dedicated software.Results: Mean balloon pressure was 11.4±3.8 atm. Pre-stent reference vessel diameter (RVD) was 3.3±0.6 mm, Dmax was 3.9±0.9 mm. Mean LCBI of the stented segment was 160±96 pre-stenting, 32±49 post-stenting and 21±35 after post-dilatation (p=0.001). The plaque burden remained constant in the stented segment; 0.48±0.1 mm² pre-stenting vs. 0.51±0.1 mm² post-stenting vs. 0.48±0 mm² after final post-dilatation (p=0.14). Conclusions:Serial IVUS-NIRS demonstrated a significant decrease of LCBI in the stented segment from pre-stenting to post-stenting and after post-dilatations, while plaque burden remained unaltered throughout PCI in relatively large RVDs. This discrepancy might possible explained by the fact that NIRS might be not detecting the lipid in larger RVDs since it is only validated in small RVDs. Research including larger numbers of patients are warranted to confirm this concept.