Dynamic natural morphologies and component changes in nonculprit subclinical atherosclerosis in patients with acute coronary syndrome at 1-year follow-up and clinical significance at 3-year follow-up

Background and aims: We aimed to explore the dynamic natural morphologies and main components of nonculprit subclinical atherosclerotic changes underlying lesion regression (LR) or lesion progression (LP) in patients with acute coronary syndrome.Methods: The primary endpoints were changes in percent atheroma volume (Delta PAV), normalized total atheroma volume (Delta TAVn) and each component in nonculprit subclinical atherosclerosis from baseline to 1 year measured by optical flow ratio (OFR) software. LR or LP was defined by an increase or decrease in PAV. Secondary endpoints included the correlation between changes in the lipid profile and Delta PAV/Delta TAVn and major adverse cardiac events (MACEs) related to nonculprit subclinical atherosclerosis at 3 years.Results: This was a subgroup analysis of our previous randomized trial with a total of 161 nonculprit lesions analysed. In the LR (approximately 55.3% of the lesions) group, Delta TAVn was positively correlated only with lipid Delta TAVn (r = 0.482, p < 0.001) but not fibrous and calcium Delta TAVn, and Delta PAV was positively correlated with lipid Delta PAV (r = 0.315, p = 0.003) but not fibrous and calcium Delta PAV. The percent reduction in low-density lipoprotein cholesterol (LDL-C) was an independent predictor of LR in multivariate logistic regression analysis (OR = 3.574, 95% CI: 1.125-11.347, p = 0.031). The incidence of MACEs related to nonculprit lesions at 3 years was higher in the LP group than the LR group (9.9% vs. 2.2%, p = 0.040).Conclusions: LR of nonculprit subclinical atherosclerosis at 1-year follow-up was mainly caused by regression of the lipid component, which was correlated with the degree of LDL-C reduction and fewer MACEs at 3-year follow-up.