The influence of lipid-containing plaque composition assessed by near-infrared spectroscopy on coronary lesion remodelling

AIMS: Vessel remodelling is commonly observed in coronary atherosclerosis, but factors influencing remodelling, such as plaque lipid content, remain poorly described. METHODS AND RESULTS: Remodelling index (RI) was calculated as the ratio of lesion to proximal and distal references external membrane area and was categorized as follows: positive (PR; RI > 1.05), intermediate (IR; RI 0.95-1.05), and negative remodelling (NR; RI < 0.95). RI was studied by near-infrared spectroscopy (NIRS) as a function of lipid content metrics, including the maximal 4 mm lipid core burden index of the segment (maxLCBI4 mm) and intravascular ultrasound (IVUS) lesion plaque burden (PB). The authors further stratified the analysis according to obstructive (≥50%) and non-obstructive (<50%) lesions using quantitative coronary angiography. Receiver-operating characteristic curves were performed to describe the maxLCBI4 mm level associated with PR. From May 2012 to November 2014, 100 de novo lesions from 67 patients underwent simultaneous NIRS-IVUS. PR was found in 28% of the lesions. There was a positive linear correlation between RI and maxLCBI4 mm (ρ = 0.58; P < 0.001). Although PR lesions had a larger PB than NR or IR (P < 0.001), the correlation of RI with maxLCBI4 mm was stronger compared with plaque volume (ρ = 0.18; P = 0.07) and with per cent PB (ρ = 0.41; P < 0.001). This relationship remained significant for obstructive (ρ = 0.72; P < 0.001) and non-obstructive lesions (ρ = 0.48; P < 0.001). By receiver-operating characteristic curve analysis, values of maxLCBI4 mm ≥ 439 were predictive for PR (area under the curve = 0.79, 95% confidence interval: 0.69-0.89). CONCLUSION: In vivo coronary lesion remodelling is positively correlated with lipid plaque content assessed by NIRS rather than simply PB. Thus, the use of NIRS can potentially aid in further stratifying vulnerable lesions.