Calcified plaque harboring lipidic materials associates with no-reflow phenomenon after PCI in stable CAD.

Calcified atheroma has been viewed conventionally as stable lesion which less likely increases no-reflow phenomenon. Given that lipidic materials triggers the formation of calcification, lipidic materials could exist within calcified lesion, which may cause no-reflow phenomenon after PCI. The REASSURE-NIRS registry (NCT04864171) employed near-infrared spectroscopy and intravascular ultrasound imaging to evaluate maximum 4-mm lipid-core burden index (maxLCBI) at target lesions containing small (maximum calcification arc < 180°: n = 272) and large calcification (maximum calcification arc ≥ 180°: n = 189) in stable CAD patients. The associations of maxLCBI with corrected TIMI frame count (CTFC) and no-reflow phenomenon after PCI were analyzed in patients with target lesions containing small and large calcification, respectively. No-reflow phenomenon occurred in 8.0% of study population. Receiver-operating characteristics curve analyses revealed that optimal cut-off values of maxLCBI for predicting no-reflow phenomenon were 585 at small calcification (AUC = 0.72, p < 0.001) and 679 at large calcification (AUC = 0.76, p = 0.001). Target lesions containing small calcification with maxLCBI ≥ 585 more likely exhibited a greater CTFC (p < 0.001). In those with large calcification, 55.6% of them had maxLCBI ≥ 400 [vs. 56.2% (small calcification), p = 0.82]. Furthermore, a higher CTFC (p < 0.001) was observed in association with maxLCBI ≥ 679 at large calcification. On multivariable analysis, maxLCBI at large calcification still independently predicted no-reflow phenomenon (OR = 1.60, 95%CI = 1.32-1.94, p < 0.001). MaxLCBI at target lesions exhibiting large calcification elevated a risk of no-reflow phenomenon after PCI. Calcified plaque containing lipidic materials is not necessarily stable lesion, but could be active and high-risk one causing no-reflow phenomenon.